:of '.? ttt&r .^^ ^T-V . . mj| JSp" ' . MEASUREMENT OF GAS AND LIQUIDS BY ORIFICE METER BY HENRY P. WESTCOTT I, Author of "" Hand Book of Natural Gas," "Hand Book of Casmgnead Gas, "Measurement of Gases \Vnere Density Changes," and ""Pressure Extensions." ASSISTED BY JOHN C. DIEHL SECOND EDITION 1922 PUBLISHED BY METRIC METAL WORKS ERIE, PENNSYLVANIA COPYRIGHTED 1922 BY METRIC METAL WORKS MINING PRESS OF ASHBY PRINTING CO ERIE PITTSBURGH PREFACE The first edition of "Measurement of Gas by Orifice Meter" published in 1918 was the first instance that we know of where the complete data pertaining to the orifice meter and orifice measurement was presented in book form, and it is gratifying to both the author and the publisher to know that the book was received with such favor as to have exhausted the edition in a comparatively short time. Due to the universal need that the first edition has met, and our desire to continue to publish authoritative infor- mation regarding the orifice meter and its varied uses, we are pleased to present this second edition. This edition has been thoroughly revised and enlarged giving more detailed and complete information, including data for the measure- ment of air, steam, water and oil. The tables of pressure extensions contained in the first edition are omitted in this book, and are now published by themselves in a book entitled "Pressure Extensions." It is hoped that this volume in its enlarged form may further establish the acceptance of orifice meter measure- ment as a standard method and assist both engineers and laymen to a greater extent than before. The author and publisher again gratefully acknowledge the valuable assistance rendered by the men who helped with the first edition as well as the assistance rendered by the engineers of the Bureau of Mines and business associates who have so kindly contributed to make this second edition more complete. o TABLE OF CONTENTS PAGE PREFACE - in PART ONE GENERAL Orifice Meter 1 Pitot Tube and Meter 2 Description of first Pitot Tube 2 Pitot Tube, Measurement of Open Flow of Gas Well 3 Oliphant Pitot Tube 3 Portable Pitot Tip and Box 5 Pitot Meter Installation V, 6 Pitot Meter Operation 6 Orifice Meter and Differential Gauge, History 11 Differential Gauges, Development 13 "Bomb Shell" Type 14 Adaptability of Orifice Meter 17 PART TWO PHYSICAL PROPERTIES OF FLUIDS Fluids ! ' 19 Theory of Constitution of Matter 19 States of Matter 19 Fluids, Liquids and Gases 20 Vapor 21 Vapor and Gas, Distinction between 21 Critical Temperatures and Pressures of Various Gases (Table) 21 Gravitation 22 Force of Gravity 22 Fluid Pressure 22 Compressibility and Expansibility of Gases 25 Expansive Power of Gases 26 Pascal's Law 27 Pressure and Liquid Head 28 Pressure Equivalents (Table) 31 Pressure Equivalents, Mercury, Water, Ib. per sq. in 32 Atmospheric Pressure 32 Barometer... 33 TABLE OF CONTENTS PART TWO PHYSICAL PROPERTIES OF FLUIDS Continued PAGE Absolute Pressure 34 Atmospheric Pressure of Gas Fields 35 Pressure Gauges 36 Spring Gauges 36 U Tubes or Siphon Gauges 38 Static Pressure 39 Vacuum 39 Vacuum Absolute Pressure (Table) 43 Pressure Base 44 Velocity 44 Uniform or varied motion 45 Acceleration 45 Velocity Head 46 Fluid Velocity 47 Coefficient of Velocity 50 Temperature 51 Absolute Temperature 51 Temperature Base 52 Perfect Gases " , . . _ 53 Charles' Law ( . 53 Boyle's Law 55 Absolute Temperature Absolute Pressure 57 Law of Perfect Gases 59 Pressure Due to Head of Gas ;*-' 62 Pressure and Gas Heads 63 Velocity Head of Flowing Gases. 64 PART THREE ORIFICE METER MEASUREMENT General Description 67 Orifice Meter Layout 69 Orifices 73 Orifice Constants (Table) 75 Orifice Meter Body ?M 76 Determination of Orifice Coefficients 77 Coefficients for Pipe Connections 77 Joplin Holder Tests 78 Derivation of Orifice Meter Formula for Flow of Air 79 Orifice Meter Formula for Gas 80 General Outline ,. ,i> 82 Leakage Tests Joplin Holder 83 TABLE OF CONTENTS PART THREE ORIFICE METER MEASURE- MENT Continued PAGE Change of Volume of Holder with Temperature 83 Procedure during Orifice Tests 91 Summary of Results of Tests 94 Comparison with Charlottenburg Tests 98 Summary of Charlottenburg and Joplin Tests 98 Erie Holder Tests 99 Erie Holder 100 Leakage Tests 101 Summary Erie Tests 104 Status of Coefficient 106 Comparison Joplin, Wann Line and Erie Tests 107 Values of Coefficient of Velocity (Diagram) 108-109 Measuring Flow of Fluids ' 110 Application Velocity Formula for Flow of Air Ill Application of Velocity Formula for Flow of Gas 112 Application of Velocity Formula for Flow of Water 113 Application of Velocity Formula for Flow of Oil 114 Mercury Float Type Differential Gauges 117 Sectional View of Differential Gauge 119 Temperature Effect on Differential Gauges 120 Accuracy of Orifice Meter 121 Percentage Variations 123 Differential Gauge Capacities 126 Differential Range 126 Special Types of Gauges 129 Differential Gauge, 2J/ inch Range 129 Combination 25 inch and 100 inch Differential Gauge 129 Indicating Gauge 130 Recording Differential and Static Pressure and Tem- perature Gauge 132 Relation Differential to Pressure 132 Relationship between Static Pressure and Location of Orifice 134 Hourly Coefficients for 4 inch Pipe (Diagram) 134 Pressure Connections or Taps 135 Friction Loss 136 Percentage of Friction Loss to Differential 136 Friction Loss vs. Capacity 139 Pressure Loss. . 141 TABLE OF CONTENTS PART THREE ORIFICE METER MEASURE- MENT Continued PAGE Pulsating Flow 143 Pulsation vs. Vibration 145 Vibration of Differential Pen Arm 145 Pulsation 146 Determination of Pulsating Flow 147 Instructions to Meter Attendants 152 Changing Orifice Meter Charts 152 Testing Apparatus 154 Inspectors Test Pump for Static Pressure Gauges 154 Vacuum Gauge Test Pump 155 Pocket Gauge for Testing Differential Gauges 156 Siphon or U Gauges 157 Permanent Gauges for Testing Differential Gauges 158 Portable Water Differential Test Gauges 159 PART FOUR MEASUREMENT OF GAS AND AIR General Description 161 Derivation of Coefficients 163 Coefficient of Velocity L 171 Hourly Orifice Coefficients for Gas 2^ and 8 Diameter Con- nections. 171 Atmospheric Pressure 14.4 173-180 Atmospheric Pressure 14.7 181-184 Specific Gravity 186 Multipliers for Revision of Coefficients 186 Multipliers for Change of Pressure Base 188 Multipliers for Atmospheric Pressure Changes 189 Multipliers for Base Temperature Changes 191 Multipliers for Changes of Flowing Temperature 192 Multipliers for Specific Gravity Changes 193 Pressure Base Multipliers (Tables) 195 Multipliers for Atmospheric Pressure Changes (Table) . . . 196 Base Temperature Multipliers (Table) 197 Flowing Temperature Multipliers (Table) 198 Specific Gravity Multipliers (Tables) 199-200 Specifications for Orifice Meter Computations for the Osage Nation 202 Values of Cv for 2^ and 8 Diameter Connections 208 Values of C v for Flange Connections 211 TABLE OF CONTENTS PART FOUR MEASUREMENT OK GAS AND AIR Continued PAGE Hourly Orifice Coefficients for Gas and Air, pressures taken at Flanges 213 Orifice Capacities for Air, Pipe Connections 214 Orifice Capacities for Gas, Pipe Connections 215 Orifice Capacities for Air, Flange Connections 216 Orifice Capacities for Gas, Flange Connections 217 Measurement of Gas in large volume 219 Effect of Atmospheric Pressure on Gas Measurement 221 Gas Contracts 230 Multiple Orifice Meter Installation 236 Installing Gas or Air Meters 239 Orifice Meter Installations for Measuring Gases. 241 Orifice Meter Body. 245 Orifice Meter Flanges 245 Gauge Line Connections 245 Orifice Meter for Coke Oven Gas 246 Installing Differential and Static Pressure Gauge 247 Setting up Gauge ..... ... .... ... . . . 247 Differential Pen Arm . 247 Adding Mercury 247 Static Pressure Connections 248 By-Pass 248 Turning on Gas or Air 249 Leaks 249 Orifice Capacities 249 Vibrating Differential Pen Arm 250 Diagrams Installations for Measuring Gas or Air. 251-254 Testing Differential Gauges for Measuring Gas or Air 255 Checking Gauge for Zero 255 Checking Differential Gauge on Pressure Lines 256 Checking Differential Gauge on Vacuum Lines 256 Checking Differential Gauges under Working Pressure 258 Adjustment 258 Testing Static Spring 258 Orifice Meter Test Report 259 Reading Charts 261 Orifice Meter Calculator 267 Form for Face of Envelope used for Filing Orifice Meter Charts T . . . . : . , , 270 ix TABLE OF CONTENTS PART FIVE MEASUREMENT OF STEAM PAGE General 271 Derivation of Coefficients 273 Properties of Saturated Steam (Table) 277 Hourly Orifice Coefficients 282, 287 Hourly Capacity of Orifice for Steam 291-292 Tests, Steam Measurement 294 Installing and Testing Steam Meters 296 Diagrams of Installations for Measuring Steam -. 303 PART SIX MEASUREMENT OF WATER General 307 Derivation of Coefficients 309 Hourly Orifice Coefficients for Water 312 Differential Pressure Extensions 313 Hourly Capacity of Orifices for Water 314 Water Measurement Tests 315 Installing and Testing Water Meters 316 PART SEVEN MEASUREMENT OF OIL General 319 Derivation of Coefficients ( . 322 Hourly Coefficients for Oil 330 Multipliers for Specific Gravity and Viscosity 331 Hourly Capacities of Orifice for Oil 332 Oil Measurement Tests 333 Installing and Testing Oil Meters 335 PART EIGHT ORIFICE CAPACITIES General. 341 Orifice Capacities for Gas, Pipe Connections (Tables) 344-383 Orifice Capacities for Gas, Flange Connections (Tables) . . 384-423 Orifice Capacity Diagrams 424-428 Information Required when Ordering Meters 425 PART ONE ORIFICE METER PITOT TUBE AND METER- HISTORY AND USES OF ORIFICE METERS AND DIFFERENTIAL GAUGES ORIFICE METER During the past decade no type of volume measuring apparatus has received as much attention as the simplest form of velocity meter, the orifice meter. This type of meter with the differential gauge has proven to be the most accurate and dependable apparatus designed for the measure- ment of gases and liquids flowing in pipe lines. It is being used successfully for measuring hydrogen, the lightest of commercial gases, and hot tar, one of the most viscous of liquids. The shape and design of the orifices have undergone minor changes, the main improvements have been made in the differential gauge which today will indicate and record readings within y^ of its total range under pressures from 28 inches of mercury vacuum to 500 Ib. per square inch. This type of meter has been recognized by the Courts and State commissions as an instrument for correct measure- ment. It has passed the acid test of reliability and millions of cubic feet of gas are paid for daily, according to its records. Many simple and complicated forms of velocity meters have been designed, but up to the present none have ob- tained any advantage over the orifice except at the expense of those most fundamental qualities, accuracy and depend- ability. 1 c . I '> ?4*. GENERAL PITOT TUBE AND METER The Pilot Tube was first used for measuring flowing streams of water and only in recent years has it been applied to measuring gas. As first constructed it measured the velocity or impact of the flowing water and indicated it in a bent glass tube. In its simplest form (Fig. 1) it consisted of a bent tube, the mouth of which was placed pointing upstream and measured the impact or dynamic pressure made by the flowing water. The water raised in the vertical part of the bent tube to-a height above the surface of the flowing stream and this height h was equal to the velocity-head V 2 /2g, so that the actual velocity V was practically equal to ^2gh. As constructed for use in streams, Pi tot's apparatus consisted of two tubes placed side by side with their submerged mouths at right angles so that when one is opposed to the current, the other stood normal to it. h _L Fig. 1 PITOT TUBE USED IN MEASURING FLOWING STREAMS Henri Pitot (Pe'tot) the inventor of the Pitot Tube, was a French Physicist and Engineer. He was born in 1695, and died in 1771. From the foregoing invention was evolved the method commonly used to measure the open flow of gas wells. 2 GENERAL In testing gas wells only one tube was used, as the gas flowing from a gas well had a free exit into the atmosphere, and con- sequently had no static pressure. Fig. 2PITOT TUBE MEASURING THE VOLUME OF GAS FLOWING FROM A GAS WELL Oliphant Pitot Tube A rough sketch of the Pitot Tube as used for the measurement of natural gas is shown in Fig. 3. The principles of this tube, however, are identically the same as those used in the more refined tube of to-day. A was a piece of s/g inch iron pipe, L- shaped and inserted in a 4 inch pipe so that the open end A came directly in the centre of the pipe. Another piece of straight % inch pipe B was placed one foot distant from the point C on the upstream side. On account of the gas flowing against the open end A, the static and dynamic pressures were trans- mitted to the U tube, while only the static pressure was 3 GENERAL transmitted from the point B. In the U tube between B and C the static pressure was counterbalanced by itself, therefore it was the dynamic pressure which caused the water in the U tube to rise to the height h. This h then /S///S/S//SS///S/SSS/S/SM^^^ Fig 3 OF PITOT TUBE USED IN MEASURING FLOWING GAS IN A PIPE LINE was the height of water, or pressure which would produce the velocity V of the gas flowing in the pipe line. The static, or gauge pressure p was observed by means of a large U tube filled with mercury, one column being con- , 4 SECTIONAL VIEW OF THE OLIPHANT PITOT TUBE, SHOWING SADDLE, TIP AND SECTION OF BRASS TUBE GENERAL nected to the connection at B and the other column open to the atmosphere. The Pitot Tube was then calibrated and the coefficient for it was determined by passing gas through it into a large gas holder under varying con- ditions of flow and pressure. Other tubes were then made by comparing them to these tubes, and as they proved very successful it was determined to make more refined tubes of various sizes, and again compare them with the gas holder, thus providing what are known as Standard Tubes with which all other tubes are compared and their co- efficients determined. Fig. 6 PORTABLE PITOT TIP AND BOX 5 GENERAL Portable Pitot Tip and Box In January, 1910, Mr. Oliphant found the need for a Pitot Tube that could be quickly and easily transported from place to place in the gas fields in order to keep a careful check on gas wells to determine whether their flow was diminishing or not, while under working conditions. This brought about the in- vention of the Pitot Tip and Box shown in Fig. 5. In this method, the Box was attached to the pipe line leading from the well and when not in use the tip was with- drawn and the opening plugged with a common pipe plug. Each line to the different wells was fitted with a similar Box and the gauge was carried from one location to another with little inconvenience. When measuring with this apparatus the regular pipe line was used instead of a 12 foot specially drilled brass tub- ing of the same size as the line. Although the error was greater than with the perfected Oliphant Pitot Tube, it served its purpose to a high degree of satisfaction. Pitot Meter Installation and Operation The best results with the Pitot Tube are obtained where it is especially de- signed for permanent installation, and when properly built and installed it becomes a scientific instrument of accur- ate measurement. It is constructed of a carefully made steel tip, having a hole about one-quarter inch in diameter, inserted in the exact center of a seamless drawn brass tube with interior surface polished and gauged to accurate and uniform size throughout its length. The tip is mounted in a saddle in such a manner as to be easily removed for cleaning, and easily reinserted to occupy exactly the pre- vious position. The size of the brass tube used is determined by the quantity of gas to be measured, and is chosen so as to produce a velocity much higher than that in the main pipe lines, in order to produce a high differential or impact pressure reading, thus greatly increasing the accuracy of 6 GENERAL the instrument by diminishing the error of observation. Each tube must be calibrated against a standard tube and a coefficient obtained, which, when multiplied by the square root of the product of the differential pressure and the static pressure (in absolute units), will give the flow in unit time. These high precision tubes are usually installed in bat- teries of two or more, for obtaining measurements of a wide range of flows, and must have a sufficient run of pipe of the same size as the tube, both ahead and behind them, to avoid eddies and counter currents in the flow. The polished interior surface of the tube, and the high velocity of the gas prevent the formation of deposits and the tube coefficient thus remains constant for a long period. Should any acci- dent occur whereby the tube becomes dented or injured in any way, it is necessary to have it repaired and recalibrated to obtain a new coefficient. It also should be borne in mind that Pitot Tube observa- tions must be made every fifteen minutes during the twenty- four hours. This requires the services of two men working twelve hour shifts. The ordinary commercial Pitot Tube should be used with caution, for in spite of its extreme simplicity it is a delicate instrument and should be handled as such. W ; hen used in ordinary pipe lines, the velocities encountered may produce differential pressures so small that it is impossible to read them with accuracy, and the interior surface of the pipe may be rough and uneven, a condition that seriously affects the result obtained with the instrument. The internal diameter of commercial pipe is not strictly uniform and is difficult to obtain with exactness, and as this factor enters into the Pitot Tube formula as the square of the value, any percentage of error in the measurement of the diameter is doubled in the effect upon the final result. A further difficulty is presented in the necessity of placing the tube in 7 GENERAL the cross section of the pipe at the point of average velocity, which point varies in the different sizes of pipe, and for dif- ferent conditions of interior surface. A better plan is to place the tip in the center of the pipe and use the coefficient obtained by actual calibration for each size of pipe. If this is done and care is taken to see that the interior of the pipe is free from sediment or dirt, and its diameter where the tip is inserted is accurately obtained, very satisfactory results may be obtained in the field with the Pitot Tube. In all cases, a free run of at least forty feet of pipe of the same size as that in which the tube is inserted must be installed on the inlet side of the tube, and ten feet on the outlet, and there must be no fittings or obstructions nearer to the tube than these distances. While the Pitot Tube is considered a very accurate meas- uring instrument, its high cost of installation and the inability to easily transport it from one location to another in the gas field caused it to be displaced by the smaller and more easily moved orifice meter with its self recording differential gauge. The invention of the recording differential gauge was the direct result of the objectionable high upkeep of the old Pitot Tube, and lack of ability to easily transport the large and cumbersome instrument from one place to another. The recording differential gauge now does the duty formerly re- quired of the employees working double shift, who read the water gauge every fifteen minutes throughout the twenty- four hours and made hand-written reports which had to be sent to the head office daily. GENERAL GENERAL Fig. 7 ONE OF THE EARLY DESIGNS OF THE RECORDING DIFFERENTIAL GAUGE AND ORIFICE FLANGE METER KNOWN AS THE "BOMBSHELL" TYPE 10 GENERAL HISTORY AND USES OF ORIFICE METERS AND DIFFERENTIAL GAUGES* "In 1910 the demand for a Pitot tube, or meter based on that principle, which could be quickly changed and more easily handled than the heavy, cumbersome Pitot tubes, developed. To meet this need and using the same principle as the Pitot Tube, the Orifice Meter was invented in the fall of 1911, by John G. Pew and H. C. Cooper of Pittsburgh, Pa. Mr. Walter Abbe, working under the direction of the above named parties, spent approximately six months con- ducting experiments at the Wilkinsburg Test Station of the Peoples Natural Gas Co. It was soon discovered that the theoretical formula worked out for the principle of the Pitot Tube, would apply for an Orifice, so that it was then mainly a matter of experiment to determine the shape of Orifice and the manner of making the connections, which would give the most consistent results and smallest variations between the high and low runs. These tests were completed in Novem- ber 1911, and the first Orifice meter for measuring gas was installed on the lines of the Hope Natural Gas Company, in West Virginia. The above tests were made at the reducing station of the Peoples Natural Gas Co., where its main lines entering the city of Pittsburgh were brought into one station and from which point the gas was distributed at lower pressures to the various lines feeding the city. It can thus be seen that these tests were run under actual working conditions at a point where any desired pressure from forty to one hundred and sixty pounds could be secured, and any volume up to fifty million feet a day was available for the tests. From that time on the Orifice meter gradually came into prominence, though there were other gas companies who dif- fered with the Peoples Natural Gas Co., as to the thickness of the Orifice discs and the manner of making connections. * By J. H. Satterwhite 11 GENERAL They decided to run their own experiments. One of the first of these was the United Natural Gas Co., of Oil City, Pa. Mr. Thomas Weymouth, of this company, conducted a large number of experiments and finally decided on the same con- nections as used by Messrs. Cooper and Pew, but used a thinner disc with a straight edge, instead of the beveled edge as originally used. Mr. Weymouth finished his experi- ments in the spring of 1913, and later tests and experiments have proven that his formulae and coefficients are correct. The next company to make their own tests relative to coefficients, was the Wichita Pipe Line Co., now the Empire Gas & Fuel Co. Their first tests were made at Joplin, Mo., where they had an old artificial gas holder to use as a standard basis of measurement. A very interesting article covering these tests and subsequent tests made at Wann, Okla., is to be found in the files of the American Society of Mechanical Engineers, December 1915, under the title of "The Flow of Air Through Thin Plate Orifices," by E. O. Hickstein. See Pages 78 to 98. These tests were started in August 1913, and completed in the spring of 1914. The Empire Gas & Fuel Co., differed slightly from the methods adopted by the Peoples Natural Gas Co., in that although they adopted the beveled edge disc, they also adopted the connections, now used extensively throughout the Mid-Continent field, of 2^ times thediameter of the pipe on the inlet side of the Orifice disc, and 8 times the diameter of the pipe on the outlet or downstream side of the Orifice disc. Subsequent tests at Erie, Penna., and at several places throughout the Mid-Continent field have proven conclusively that the coefficients adopted for this method of connection are absolutely correct. There have been during the past four years, quite a few tests that really have no official standing other than that they were check tests, all of which have proven that the original work along these lines was correct, and that it is now 12 GENERAL optional to the user as to whether he desires to use flange connection Orifice meters, or meters that use what is called full flow (2^2 and 8 times the diameter) connections. The main tihing to be remembered is, that when using the full flow connections the static pressure must be taken from the upstream side of the Orifice, while for flange connections it is taken from the downstream side. Differential Gauges After the Peoples Natural Gas Co. had completed their original tests and determined the ac- curacy and adaptability of the Orifice meter, it was found necessary to develop a gauge that would record the differ- ential or drop in pressure from one side of the Orifice disc to the other. It is this development of the recording differential gauge that forms one of the most interesting and important stages of Orifice meter development of later years. At the time when the original experiments covering co- efficients were completed there was no instrument on the market for recording differential pressure. It was found however, that one of the gauge manufacturers did make a recording gauge that recorded pressure in terms of inches of water. On the night of November 5th, 1911, at a private residence in Pittsburgh, a meeting of several young men interested in this work was held. At this meeting the encased type differential gauge, commonly called the "Bomb Shell" was developed. This consisted of a skeleton con- structed common recording pressure gauge, with chart graduated in inches of water pressure, encased within a heavy casting. This casting was slightly larger than the recording gauge and made to stand a high pressure. It had a cover bolted on, and through the cover were two peep holes, through which one could watch the action of the gauge within. From the spring a line leading through the casting was connected to the high or upstream side of the Orifice, which permitted the higher pressure to be exerted on the inside of the spring. 13 GENERAL From the low or downstream side of the Orifice another line was connected to the casting, filling same with gas, so that the lower pressure was exerted on the outside of the spring. The spring would then record the difference between the two pressures, which was the differential drop in pressure across the Orifice disc. This was rather a crude differential gauge, and its weight made it quite a cumbersome affair. It was however, the best that could be secured in the short time allowed, and afterwards proved to be the best gauge of its type, until the mercury float type differential gauge was developed in later years. There are still a large number of "Bomb Shells" in operation in West Virginia and Pennsylvania, and outside of the fact that the springs have to be replaced frequently, they are giving very good satisfaction. The gauge manufacturers immediately took up the work of designing a differential gauge that would give satisfactory service and eliminate the objectionable features of the "Bomb Shell." They turned out during the next few years quite a few types of differential gauge, using springs, but they all had the same trouble as the "Bomb Shell," namely that it took too many springs to keep them in operation and they were not sensitive enough. The Bristol Co., of Waterbury, Conn., was the first of the gauge manufacturers to get out a mercury float type differ- ential gauge, and there are a few of these that are now obsolete in the fields. This gauge never gave satisfaction, as it could not be kept adjusted, and besides was constantly losing mer- cury. Under these conditions it was not as good as the spiring type. However, they had the right idea, as has been proven, namely using a mercury seal instead of a spring, and it never has been thoroughly understood why their engineers dropped the gauge at this point and did not perfect it, unless as has been stated, they did not desire to go into the Orifice meter business. 14 GENERAL Fig. 8 "BOMBSHELL" TYPE DIFFERENTIAL GAUGE. COVER REMOVED. NOTE LARGE PIPE DEADENERS IN GAUGE LINES 15 GENERAL Fig. 9 ANOTHER VIEW OF "BOMBSHELL" TYPE GAUGE 16 GENERAL Natural Gas Companies Develop Proper Gauge The gas companies realized the importance of a high class differential gauge and from two entirely different sources plans were started to develop a mercury float type differ- ential gauge; one in the Mid-Continent fields, and the other in the Ohio fields. From their investigations and plans were developed the two differential gauges that are on the market today. Both of these gauges have undergone a large number of improvements since their invention in 1914 and who can say that there are not a large number of im- provements still to come. Adaptability of Orifice Meter The Orifice meter is now used for the measurement of coke oven gas, manufactured gas of all kinds, steam, water and oil. It will be seen from the above that the adaptability of this type of meter for the measurement of both gases and liquids is practically unlimited. These different uses for which the Orifice meter is adapted simplifies the work of the purchasing agent* especially the purchasing agent who would have to contend with the pur- chasing of meters for both gases and liquids. By adopting the Orifice meter, all he has to do is to watch his warehouse stock and keep same replenished. If an engineer desires a meter to measure gas, he can go to the warehouse and secure one. If another man desires a meter to measure oil he can go to the warehouse and secure the same kind of me,ter, which also applies to the man who desires to measure steam. Different coefficients are applied, according to the gas or liquid which they desire to measure, but the apparatus is the same. It is not altogether the desire for a meter which will give them correct measurement that has caused so many engineers to adopt the Orifice meter, but there is another factor entering into its use that has strongly appealed to them. That is the Orifice meter will tell them to a large extent exactly 17 GENERAL what is taking place in the lines or at their plants. For instance, the meter measuring oil at a refinery, not only tells the engineers how much oil has been used during the past twenty-four hours, but also tells them the rate per hour, also whether their pumper has been keeping his pumps going at a uniform rate of speed, or whether he pumps too much one hour and not enough another hour. It helps them greatly in smoothing out their operations, so that they can secure greater efficiency and better products at a uniform rate of operation. The same idea applies when measuring steam, as the engineer then knows exactly how to handle his boiler room under different and varying loads, and knows how these loads are pro-rated throughout the plant. Likewise, in the gas business it tells its own story, in that the superintendent will know whether his field men are drawing on his wells at a uniform rate of flow or whether they pull on one well hard for a while, and then ease up and draw on another one heavy for a while. This is especially desirous at this time, when so many of the states in the Mid- dle West have passed laws regulating the percentage of the open flow of a gas well that may be taken in twenty-four hours. It likewise helps the town superintendent in pro- viding daily records enabling him to properly take care of his varying loads. The pipe line superintendent can also tell whether his men are taking proper care of the drips along the line, because a heavy accumulation of gasoline conden- sate or water in the lines would be shown on the Orifice meter chart by a vibration of the differential pen arm. It can thus be seen that not only does the Orifice meter measure accurately the liquid or gas passing through the pipe line, but also gives its owner a definite record of what is transpiring relative to various operations." 18 PART TWO PHYSICAL PROPERTIES OF FLUIDS The flow of fluids follows the physical laws which were discovered centuries ago. These laws and the properties of fluids which are the basis of the derivation oi: the simple formula for the flow through an Orifice are explained in de- tail in the following pages. No attempt is made to explain the problems of thermodynamics, pneumatics, etc., but only to give an outline of those laws leading up to the formula universally used. Theory of the Constitution of Matter Physicists have generally adopted the following theory of the constitution of matter. Every body of matter is composed of exceedingly small particles, called molecules, in other words, every body is the sum of its molecules. No two molecules of matter in the universe are in contact with each other. Every molecule of a body is separated from its neighbors, on all sides, by inconceivably small spaces. Every molecule is in quivering motion in its little space, moving back and forth between its neighbors, and rebounding from them. When we heat a body we simply cause the molecules to move more rapidly through their spaces; so they strike harder blows on their neighbors, and usually push them away a very little; hence, the size of the body increases. This theory seems, at first, little more than an extravagant guess. But it shall be found that this theory enables us to account for most of the known phenomena of matter. States of Matter For the purposes of subdivision we may say that matter exists in three distinct states, the solid, the liquid, and the gaseous. In addition, however, to states 19 PHYSICAL PROPERTIES OF FLUIDS which fulfill the definitions of a solid, a liquid, or a gas, which we shall give later on, it will be found that there are inter- mediate states which bridge over the intervals between the solid and the liquid, and the liquid and the gas. As an ex- ample of the kind of gradation which exists, we may take the following: steel, lead, wax, cobbler's wax (which will flow like a liquid if allowed sufficient time), water, ether, steam, air, hydrogen. In addition there is the critical state when a substance is to all intents and purposes both a liquid and a gas. We may define a solid as a portion of matter which is able to support a steady longitudinal stress without lateral support. In contradistinction, a portion of matter which is unable to support a steady longitudinal stress without lateral support is called a fluid. If we take a solid body, say a lead pencil, then we may apply a deforming force, either of compression or extension, in any direction to the pencil, and there will be a certain amount of strain, either elongation, compression, or bending produced, which will call into play a stress that will be in balance with this force, and this stress will be produced without the body being supported in any way in a direction at right angles to that along which the stress acts. In the case of a fluid, such as water or air, we are unable to exert a stress on it, and hence produce a corresponding strain, unless we supply some constraining boundary which shall prevent the fluid swelling out at right angles to the line of action of the stress. Fluids, Liquids and Gases Fluids are divided into liquids and gases. A liquid is a fluid such that when a certain volume is introduced into a vessel of greater volume it only occupies a portion of the vessel equal to its own volume. A gas is a fluid such that if a certain volume is introduced into a vessel, then, whatever the volume of the vessel may be, the gas will distribute itself throughout the vessel. 20 PHYSICAL PROPERTIES OF FLUIDS Vapor Vapor is essentially the same as gas, but the word vapor is conveniently limited to the gaseous state of a body which is liquid or solid at ordinary temperatures, while the term "gas" is applied to those fluids which are in that rarified state at ordinary temperatures. Vapor and Gas A vapor is a substance in the gaseous state at any temperature below the critical point. A vapor can be reduced to a liquid by pressure alone, and may exist as a saturated vapor in the presence of its own liquid. A gas is the form which any liquid assumes above its critical temperature, and it cannot be liquefied by pressure alone, but only by combined pressure and cooling. The critical point is the lowest temperature of a gas at which it cannot be liquefied by pressure. The critical point is the line of demarcation between a vapor and a gas. The temperature of the substance at the critical point is the critical temperature. The pressure which at the critical temperature just suffices to condense the gas to the liquid form is called the critical pressure. Table 1 CRITICAL TEMPERATURES AND PRESSURES OF VARIOUS GASES Chemical Critical Critical Gases or Vapors Formula Temp. deg. Pressure, Ib. fahr. per sq. in. abs. Water H 2 689 2940 Ammonia NH 3 266 1691 Acetylene C 2 H 2 99 Carbon Dioxide C0 2 88 1103 Ethylene C 2 H 4 50 760 Methane CH 4 -115 807 Oxygen 2 -182 747 Argon A 2 -186 744 Carbon Monoxide CO -219 522 Air -220 573 Nitrogen N 2 -231 515 Hydrogen H 2 -389 294 21 PHYSICAL PROPERTIES OF FLUIDS Gravitation That attraction which is exerted on all matter, at all distances, is called gravitation. Gravitation is universal, that is, every molecule of matter attracts every other molecule of matter in the universe. The whole force with which two bodies attract one another is the sum of the attractions of their molecules, and depends upon the number of molecules the two bodies collectively contain, the mass of each molecule, and the distance between the bodies. What is understood by the weight of a body is the mutual attraction between it and the earth. The force of gravity varies with the distance from the center. Observations made in various ways show that the force of gravity varies over the surface of the earth. Now it is found that the nearer an object without the earth's sur- face is to the center of the earth, the greater is the force of gravity. The polar diameter of the earth is about 26 miles less than its equatorial diameter, and consequently, the dis- tance from the center to the surface at the poles is 13 miles less than to the surface at the equator. This considerable difference in distance from the center occasions an appreci- able difference between the weight of a body (having any considerable mass) at the equator and at the poles; and, since the distance of the surface from the center constantly in- creases as we go from the poles toward the equator, the weight of all objects transported from the poles toward the equator constantly diminishes. Fluid Pressure With the exception of the phenomena of capillarity and those occasioned by difference in compres- sibility and expansibility, liquids and gases are governed by the same laws. We are placed on the borders of two oceans. A watery ocean borders our land; an aerial ocean, which is called the atmosphere, surrounds us. Every molecule, in both the gaseous and liquid oceans, is drawn toward the earth's center 22 PHYSICAL PROPERTIES OF FLUIDS PHYSICAL PROPERTIES OF FLUIDS Fig. 11 ORIFICE METER ON LARGE GAS MAIN PHYSICAL PROPERTIES OF FLUIDS by gravity. This gives to both fluids a downward pressure upon everything upon which they rest. The gravitating power of liquids is everywhere apparent, as in the fall of drops of rain, the descent of mountain streams, the power of falling water to propel machinery, and the weight of water in a bucket. The downward pressure of air is indicated by a barometer. Compressibility and Expansibility of Gases The in- crease of pressure attending the increase in depth, in both liquids and gases, is readily explained by the fact that the lower layers of fluids sustain the weight of all the layers above. Consequently, if the body of fluid is of uniform density, as is very nearly the case in liquids, the pressure will increase in nearly the same ratio as the depth increases. But the aerial ocean is far from being of uniform density, in consequence of the extreme compressibility of gaseous matter. The contrast between water and air, in this respect, may be seen in the fact that water, subjected to a pressure of one atmosphere, contracts .0000457 of its volume; under the same circumstances, air contracts one-half. For most practical purposes, we may regard the density of water at all depths as uniform, while it is far otherwise in large masses of gases. The pressure at different depths in liquids may be illus- trated by piling several bricks one on another, when the pressure that different bricks sustain varies directly with their depths below the upper surface of the pile. On the other hand, pressure of gases at different depths may be illustrated by piling fleeces of wool one on another. Since the volume of each successive fleece varies with the weight it bears, the pressure which different fleeces sustain are not proportional to their respective depths below the upper surface of the pile. At twice the depth, there would be much more than twice the pressure, because the lower point would sustain more than twice the number of fleeces. 25 PHYSICAL PROPERTIES OF FLUIDS Closely allied to compressibility is the elasticity of gases, or their power to recover their former volume after com- pression. The elasticity of all fluids is perfect. By this is meant, that the force exerted in expansion is always equal to the force used in compression; and that, however much a fluid is compressed, it will always completely regain its former bulk when the pressure is removed. Liquids are perfectly elastic; but, inasmuch as they are perceptibly compressed only under tremendous pressure, they are re- garded as practically incompressible and so it is rarely necessary to consider their elasticity. It has already been stated that matter in a gaseous state expands indefinitely, unless restrained by external force. The atmosphere is confined to the earth by the force of gravity. Expansive Power of Gases The property of gases which distinguishes them from other fluids is that a given mass of gas, when introduced into a closed vessel, always exactly fills the vessel, whatever its volume. Thus if we have two equal closed vessels connected together by a tube which can be closed by means of a tap, and one of these vessels is filled with a gas, say air at the ordinary pressure, while the other does not contain any matter, or, in other words, has a vacuum inside, then, on opening the tap, the air immediately expands and rushes into the second vessel, till finally there is the same quantity of gas in each vessel. By again closing the tap and exhausting the air from one of the vessels by means of an air pump, and then opening the tap, the remaining gas again expands and fills the two vessels. This operation may be repeated indefinitely, and in every case the gas left in the one vessel will, when the tap is opened, expand and fill the two vessels. This experiment illustrates the expansive power of gases. Since the gas enclosed in a vessel always expands and completely fills the vessel, even if this latter is increased in volume, it follows that the gas must exert a pressure on the 26 PHYSICAL PROPERTIES OF FLUIDS inside of the containing vessel. That this is so can be shown by enclosing some air at ordinary atmospheric pressure in a thin glass flask, and then removing the air from outside the flask by placing it beneath the receiver of an air pump, when, unless the flask is fairly strong, the pressure exerted by the air inside the flask will be sufficient to burst the flask. The reason that the flask does not burst before the air surrounding it is removed, is that the air surrounding the flask presses on the outside of the flask and counteracts the effect of the pressure of the enclosed air on the inside. When the air outside is removed by means of the pump there is no pressure exerted on the outside, and the flask may not be strong enough to withstand the inside pressure. Pascal's Law An exterior pressure applied to a fluid is transmitted equally in all directions, or the pressure per unit of area exercised inward upon a mass of fluid is transmitted undiminished in all directions, and acts with the same force upon all surfaces in a direction at right angles to those sur- faces. Hence, the pressure applied to any area of a confined fluid is transmitted to every other equal area through all Fig. 12 DIAGRAM ILLUSTRATING PASCAL'S LAW the fluid to the walls of the containing chamber without diminution, as shown in the diagram above. According to this law, the gas pressures in the various parts of a "contin- uous and connected reservoir" must be equal. The total pressure acting upon any definite portion of the surface is 27 PHYSICAL PROPERTIES OF FLUIDS equal to the pressure exerted by the head of fluid itself plus the effect of the exterior pressure, which is transmitted by the fluid. PRESSURE AND LIQUID HEAD F 4 1 K L\ . =^x?^>i L^r^l^l : ! : = = = ^-=-- S -'--3 r^ A B C D m f", m 5" 1 / -I? Fig. 13 Fig. 14 The fact that the pressure of a liquid depends only upon the head may be illustrated by the above diagrams. As- suming the above vessels as one inch wide and filled with water to the elevations indicated, the total pressure acting on the surface A to D is 48 cubic inches of water or 4 cubic inches of water on each square inch. Since BC is 2 inches the total pressure acting on BC is 2X4 or 8 cubic inches. The total pressure acting on EF is equal to the pressure at BC plus the weight of the column of water BE. Column BEFC contains 32 cubic inches. Therefore the total pressure on EF equals 32+8 or 40 cubic inches. Since EF is 2 square inches in area, the pressure per square inch is 20 cubic inches of water, or a pressure equal to 20 inches head of water which is the height of the surface above EF. 28 PHYSICAL PROPERTIES OF FLUIDS In Fig. 14 the pressure acting on RS is 16 inches head of water. Since this pressure is transmitted equally in all directions the pressure acting on each square inch from Q to T is also equal to the weight of 16 cubic inches of water. If this fact is not true and the pressure near T is less than at S then the water would flow from S toward T. Since these points are on the same level and the water is not in motion the pressure at each point must be equal to the pressure at the other point. This pressure acts upward on the container from Q to R from S to T as well as downward on the liquid at this level. Therefore the total pressure from Q to T is 16X12 or a weight of 192 cubic inches of water. The total pressure on surface OP is equal to the pressure at QT plus the weight of the water between QT and OP as the sides QO and TP are vertical. This latter volume equals 4X12 or 48 cubic inches. Therefore the total pressure on OP equals 48+192 or 240 cubic inches of water on 12 square inches of surface or weight of 20 cubic inches of water per square inch. The pressure acting on this surface is 20 inches of water head. Therefore, liquid pressure depends only on the head of liquid and density and not on total area. The expression "feet head of liquid" is equivalent to a pressure per inch equal to the weight of a column of liquid; one square inch in area of a height equal to the feet head. If gasoline is used as a liquid the head in inches of gasoline on each area would be the same as for water but the pressure per square inch would be less depending on the relative densities of gasoline and water. We conclude, therefore, that the total pressure on the bottom of a vessel depends on the depth, the area of the bottom, and the density of the liquid, and is independent of the shape of the vessel and the quantity of liquid. The important fact that the pressure on the bottom does not depend on the shape of the vessel is often called the hydro- static paradox, because though true, it seems at first absurd. 29 PHYSICAL PROPERTIES OF FLUIDS The pressure due to gravity on any portion of the bottom of a vessel is equal to the weight of a column of that liquid whose base is the area of that portion of the bottom pressed upon, and whose height is the greatest depth of the liquid in the vessel. Evidently the lateral pressure at any point of the side of a vessel depends upon the depth of that point; and, as depth at different points of a side varies, hence, to find the pressure upon any portion of a side of a vessel, we find the weight of a column of water whose base is the area of that portion of the side, and whose height is the average depth of that por- tion. Thus, we compute the total pressure on the side UVRS of the vessel (Fig. 14), by multiplying the area of the side 32 square inches (dimensions, 16X2 inches), by the depth to the middle point, 8 inches. The total pressure is equal to the weight of 256 cubic inches of water. From the preceding paragraphs it is evident that the head of fluid acting on a surface may be expressed in terms of head of any other fluid or in terms of pressure per square inch, also that the pressure per square inch may be expressed in terms of liquid head. Since the weight of water is 62.355 pounds per cubic foot, a column of water one foot high and one square foot in area exerts a pressure of 62.355 pounds on the square foot of sur- face, 62.3551b. per square foot, or 0.43302 pounds per square inch. Therefore, a column of water one foot high and one square inch in area is equivalent to a pressure of .43302 pounds per square inch, and one pound per square inch equals 2.3094 feet water head, or one pound per square inch equals 27,71 inches of water. One inch of water head exerts pressure of .03609 pounds per square inch. Since the average at- mospheric pressure of the gas fields is 14.4 pounds per square inch, it maybe expressed asequal to (14.4X2,3094) or 33.3 feet water head. It also may be expressed as 399 (14.4X27.71 = 399) inches water head. In the same manner one inch of 30 PHYSICAL PROPERTIES OF FLUIDS Table 2 PRESSURE EQUIVALENTS Ounces In. Water In. Mer- cury In. Mer. cury Ounces In. Water In. Water In. Mer- cury Ounces .25 .43 .032 1. 7.85 13.60 .25 .018 .144 .50 .87 .064 1.5 11.78 20.40 .50 .037 .259 .75 1.30 .095 2. 15.71 27.20 .75 .055 .433 1. 1.73 .127 2.5 1.23 Ib. 34.00 1. .074 .577 2. 3.46 .26 3. 1.47 " 40.80 2. .147 1.15 3. 5.19 .38 3.5 1.72 " 47.60 3. .22 1.73 4. 6.92 .51 4. 1.96 " 54.40 4. .29 2.31 5. 8.65 .64 4.5 2.21 " 61.20 5. .37 2.89 6. 10.38 .77 5. 2.45 " 68.00 6. .44 3.46 7. 12.11 .89 5.5 2.74 " 74.80 7. .51 4.04 8. 13.85 1.02 6. 2.94 " 81.60 8. .59 4.62 9. 15.58 1.15 6.5 3.19 " 88.40 9. .66 5.20 10. 17.31 1.27 7. 3.44 " 95.20 10. .74 5.77 11. 19.05 1.40 7.5 3.68 " 102.00 11. .81 6.35 12. 20.78 1.53 8. 3.93 " 108.80 12. .88 6.93 13. 22.51 1.66 8.5 4.17 " 115.61 13. .96 7.51 14. 24.24 1.78 9. 4.42 " 122.41 14. 1.03 8.08 15. 25.97 1.91 9.5 4.66 " 129.21 15. 1.10 8.66 16 or 1 Ib. 27.71 2.04 10. 4.91 " 136.01 16. .18 9.24 1 Ib.loz. 29.44 2.16 10.5 5.15 " 142.81 17. .25 9.82 " 2 " 31.17 2.29 11. 5.40 " 149.61 18. .32 10 . 39 " 3 " 32.90 2.42 11.5 5 . 64 " 156.41 19. .40 10.97 " 4 " 34.63 2.55 12. 5 . 89 " 163.21 20. .47 11.55 " 5 " 36.36 2.67 12.5 6.14 " 170.01 21. .54 12.13 " 6 " 38.09 2.80 13. 6.38 " 176.81 22. .62 12.70 " 7 " 39.82 2.93 13.5 6.63 " 183.61 23. .69 13.28 g 41.56 3.06 14. 6.87 " 190.41 24. .76 13.86 " 9 " 43.29 3.18 14.5 7.12 " 197.21 25. .84 14.44 " 10 " 45.02 3.31 15. 7.36 " 204.01 26. .91 15.01 n 46.76 3.44 15.5 7 61 " 210.81 27. .99 15.59 " 12 " 48.49 3.57 16. 7.85 " 217.61 27.71 2.04 16 or 1 Ib. 13 50.22 3.69 16.5 8.10 " 224.41 29. 2.13 1.05 Ib. 14 51.95 3.82 17. 8.34 " 231.21 30. 2.21 1.08 " " 15" 53 . 68 3.95 17.5 8 . 59 " 238.01 31. 2.28 1.12 " 21b. 55.42 4.07 18. 8.83 " 244.81 32. 2.35 1.15 " 2 Ib. loz. 57.15 4.20 18.5 9.08 " 251.61 33. 2.43 1.19 " " 2 " 58.88 4.33 19. 9.33 " 258.41 34. 2.50 1.23 " 3 60.62 4.46 19.5 9.57 " 265.21 35. 2.57 1.26 " 4 62.35 4.59 20. 9.82 " 272.01 36. 2.65 1.30 " 5 64.08 4.71 20.5 10.06 " 278.81 37. 2.72 1.34 " 6 65.81 4.84 21. 10.31 " 285.61 38. 2.79 1.37 ' " 7 " 67.54 4.97 21.5 10.55 " 292.41 39. 2.87 1.41 " 8 " 69.27 5.10 22. 10.80 " 299.21 40. 2.94 1.44 " 9 " 71.01 5.22 22.5 H.04 " 306.01 41. 3.01 1.48 " 10 " 72.74 5.35 23. 11.29 " 312.81 42. 3.09 1.52 " 11 " 74.47 5.48 23.5 11.53 " 319.61 43. 3.16 1.55 " 12 " 76.20 5.60 24. 11.78 " 326.41 44. 3.24 1.59 " 13 " 77.93 5.73 24.5 12.02 " 333.21 45. 3.31 1.62 " 14 " 79.67 5.86 25. 12.27 " 340.02 46. 3.38 1.66 " 15 " 81.40 5.99 25.5 12.52 " 346.82 47. 3.46 1.70 31b. 83.13 6.11 26. 12.76 " 353.62 48. 3.53 1.73 " loz. 84.86 6.24 26.5 13.01 " 360.42 49. 3.60 1.77 " 2 " 86.59 6.37 27. 13.25 " 367 . 22 50. 3.68 1.80 3 88.33 6.50 27.5 13.50 " 374.02 51. 3.75 1.84 : 4 90.06 6.62 28. 13.74 " 380 . 82 52. 3.82 1.88 g 91.79 6.75 28.5 13.99 " 387.62 53. 3.90 1.91 " 6 " 93.52 6.88 29. 14.23 " 394.42 54. 3.97 1.95 " 7 " 95.65 7.01 29.5 14.48 " 401.22 55.42 4.07 2. Ib. " 8 " 96.98 7.13 30. 14.7^2 " 408.02 31 PHYSICAL PROPERTIES OF FLUIDS mercury is equivalent to .4908 pounds per square inch as one cubic inch of mercury weighs .4908 pounds. One inch of .4908 mercury is equal to .03609 or 13.6 inches of water. Pressure Equivalents. One inch of mercury = .4908 Ib. per square inch. One inch of mercury = 13.6 inches of water. One foot of water, 62 deg. fahr. = 62.355 Ib. per square foot. One foot of water, 62 deg. fahr. = .43302 Ib. per square inch. One inch of water, 62 deg. fahr. = .03609 Ib. per square inch. One inch of water, 62 deg. fahr. = .07353 inches of mercury. One pound per square inch = 2. 0375 inches of mercury. One pound per square inch = 27. 712 inches of water. One pound per square inch = 2. 3094 feet of water. ATMOSPHERIC PRESSURE -rA 30' Fig. 15 If the closed end of the U tube, (Fig. 15) having a bore one square inch in area, is filled with mercury, and then in- verted ; the mercury in the closed arm will sink to A, and will rise in the open arm to C. At sea level the surface A is 30 inches higher than the surface C. This can be accounted for 32 PHYSICAL PROPERTIES OF FLUIDS only by the atmospheric pressure. The column of mercury BA, containing 30 cu. inches, is an exact counterpoise for a column of air of the same area extending from C to the upper limit of the atmospheric ocean, an unknown height. The weight of the 30 cu. inches of mercury in the column BA is 14.7 lb., which is the weight of a column of air of one square inch section, extending from the surface of the sea to the upper limit of the atmosphere. But gravity causes equal pressure in all directions. At the level of the sea, all bodies are pressed upon in all directions by the atmosphere, with a force of about 14.7 lb. per square inch, over one ton per square foot. R egardless of the size of the bore of the tube the pressures per square inch would be the same, and as liquid head is independent of the shape of the container, the head would be the same for any shape of tube. -30" -20' -10" Y\ Fig. 16 Barometer Fig. 16 represents another form of apparatus which is more commonly used for ascertaining atmospheric pressure. It consists of a straight glass tube about 36 inches long, closed at one end, and filled with mercury. When this tube is inverted, the open end having been covered with a finger and plunged into an open cup of mercury, and the 33 PHYSICAL PROPERTIES OF FLUIDS finger withdrawn, the mercury in the tube will sink until it balances the atmospheric pressure. This experiment was devised by Torricelli, an Italian. The apparatus is called a barometer. The empty space above the mercury in the tube is called a Torricellian vacuum. If water is used in a very long tube instead of mercury the height XY would be about 34 feet or 13.6 times as high as for mercury at sea level. If the barometer is carried up a mountain, it is found that the mercury constantly falls as the ascent increases. This shows that the pressure is less near the top of the aerial ocean than near its bottom. It is found that the pressure increases very rapidly upon descending when near the bot- tom. The density of the air at a height of 3 miles is but little more than y% the density at the sea level; at 6 miles, J4; at 9 miles, y%', at 15 miles, j^] at 35 miles it is calculated to be only 3oooo> so that the greatest part of the atmosphere must be within that distance of the surface of the earth. On the other hand, if an opening could be made in the earth, 35 miles in depth below the sea. level, it is calculated that the density of the air at the bottom would be 1,000 times greater than at the sea level, so that water would float in it. The average height of mercury in the vacuum column above the mercury varies with the altitude of the places and in most of the gas fields is about 29.34 inches which is equal to 14.4 pounds per square inch (29.34 X. 4908 = 14.4). Absolute Pressure If several glass tubes of various areas, sealed at one end are filled with the mercury, the open ends immersed in a deep bowl of mercury (as in Fig. 16) and the sealed ends lifted above the mercury, the tubes will remain filled with mercury until the sealed ends are lifted to a certain level above the surface of the mercury, before a vacant space will be formed, after which any additional elevation of the tubes will fail to increase the height of the mercury in the tubes above the surface of the mercury in the 34 PHYSICAL PROPERTIES OF FLUIDS bowl. The elevation of the mercury in the columns then indicates the atmospheric pressure as the vacant space above the mercury is practically a vacuum. If the whole ap- paratus including the bowl is then placed in a glass container connected with a vacuum pump and the air is pumped from the container, the mercury in the columns will fall until the air in the container is exhausted when the levels of the mer- cury in the columns will nearly reach the level of the mercury in the bowl. Due to leakage etc. it will never be possible to obtain a condition when the surfaces will be on the same level. The condition when the surfaces would be level is the entire absence of pressure on the outside of the tubes, the perfect vacuum or the absolute zero of pressure. This point is called the zero of absolute pressure. See Fig. 20. The zero point of absolute pressure is a perfect vacuum. Like the zero of absolute temperature, it does not exist ex- cept theoretically. To express pressures in absolute units the gauge pressure must be added to the atmospheric pressure. The solution of all problems in gas measurement is greatly simplified by expressing all pressures in absolute units. To express pressures in absolute units the atmospheric pressure must be added to the gauge pressure. For example if the gauge pressure is 10 Ib. per square inch and the atmospheric pressure is 14.4 Ib., the absolute pressure is (10.0+14.4) or 24.4 Ib. per square inch. See Fig. 20. Likewise, a line pressure of 20 inches of mercury is equal to an absolute pressure of (20+29.34) or 49.34 inches of mercury, where the atmospheric pressure is 29.34 inches of mercury. Atmospheric Pressure of Gas Fields Some years ago Mr. F. H. Oliphant, at that time of the United States Geo- logical Survey, considered as a basis of natural gas measure- ment a pressure of 14.65 pounds per square inch absolute, and a temperature of 60 deg. fahr., and since then it has become customary for natural gas men to refer their gas measurements to this basis. A pressure of 14.65 pounds per 35 PHYSICAL PROPERTIES OF FLUIDS square inch is 4 ounces above the assumed atmospheric pressure of 14.4 pounds per square inch, the latter being the average at about the elevation of the Great Lakes, which elevation was considered as fairly representing that of most gas fields. Pressure Gauges The pressure acting upon, or exerted by fluids is expressed usually in pounds per square inch, inches of mercury, inches of water and feet head of fluid. It is indicated by spring gauges, siphon gauges or U tubes, and sometimes by ordinary vertical columns of liquids. The ordinary gauge spring is usually made of light hollow brass tubing, one end sealed, coiled in form of a horseshoe or around a circular rod, the open end being fixed to suitable appliances for connections to pipes, etc., in which is contained the fluid whose pressure is desired, the closed end being connected to an indicating pointer or pen arm either directly or by means of levers. When the pressure on the inside of the tube is the same as on the outside, the pointer will re- tain a fixed zero position but as pressure on the inside in- creases and becomes greater than the outside pressure the tube expands and tends to straighten the coil causing the arm attached to the sealed end to rotate by equal distances for equal increases in pressure. Thus a spring which is set at zero with the atmospheric pressure at sea level acting on the inside and outside will retain the same zero position on top of Pike's Peak when open to the atmosphere. If the gauge is placed in a tight container under pressure with the same pressure on the inside and outside of the spring, the pen will still retain its zero position. Therefore, a spring gauge is a differential pressure gauge, that is, it indicates a difference in pressure. This difference is usually above and sometimes below atmospheric pressure. The pressure above atmospheric pressure is generally expressed in pounds per square inch and below atmospheric pressure in inches of mercury vacuum. Gauges are marked to indicate pressures 36 PHYSICAL PROPERTIES OF FLUIDS Fig. 17 PRESSURE SPRING. STUFFING BOX OF DIFFERENTIAL GAUGE SHAFT EXTENDING THROUGH CENTER OF SPRING Fig. IS PRESSURE GAUGE USED FOR TESTING 37 PHYSICAL PROPERTIES OF FLUIDS in various units, such as pounds per square inch, ounces per square inch, inches of water, feet of water, etc. When a tap is made in a line containing liquid under pres- sure and a vertical tube is attached to the line the liquid will rise in the tube a certain height depending upon the pressure and the weight of the fluid per unit volume. The height will increase with the pressure. Thus, if the pressure in a water line is ten pounds ; that is, ten pounds per square inch greater than the atmosphere, the water will rise 277.1 inches (23.09 feet) in the tube. For small differences of pressure a glass U gauge is used. Various liquids are used depending upon the range of the gauge and character of fluid whose pressure is to be determined. The pressure difference is the difference of the surfaces of the liquids in the col- umns of the U tube. If mercury is used in the gauge and the tube C is connected to the container of fluid with D open to the atmosphere the pres- sure in the container is m inches of mercury greater than the atmosphere. If this tube is connected across an orifice in which a liquid is flowing, for example, water, and each column and connecting lines D and C are filled with water above the mercury, the difference in height of the surfaces of the mercury does not represent the true difference in pressure due to the fact that difference in levels m is partially offset by a column of water, m inches high, in the opposite leg A. Therefore, the total difference in pressure is equal to m inches of mercury minus m inches of water and since each inch of water is equal to .0735 inches of mercury, the pressure differential is m .0735 m or 0.9265 m inches of mercury. In the case of gases the fact is that the difference in liquid levels in the U tube is also offset by a column of m inches of air, but air is so light when compared with liquids that the effect is entirely disregarded. PHYSICAL PROPERTIES OF FLUIDS Static Pressure In orifice meter data the line pressure above the atmosphere is usually known as the static pressure or standing pressure, to distinguish this pressure from the differential pressure which is a pressure difference due to flow. 50 Ftg. Vacuum Ordinary use of this term means merely a partial diminution of pressure below the normal atmospheric pressure or zero gauge pressure. This is the engineering conception of the term as used in this book. The maximum degree attainable with ordinary engineering appliances is about 14 pounds below atmospheric. One of the best ex- amples of vacuum is an incandescent light bulb. In break- ing off the tip after placing under water, the bulb is nearly 39 PHYSICAL PROPERTIES OF FLUIDS filled with water because the water is under the pressure of the atmosphere, and the interior of bulb, prior to breaking, was under a minus pressure or less than atmospheric. Vacuum is usually expressed in inches of mercury. Reference to Fig. 20 shows that vacuum is indicated on a gauge in the reverse direction from the pressure. One inch mercury vacuum is equal to 0.4908 Ib. per sq. in. Therefore, the absolute pressure corresponding to mercury vacuum equals 14.4 .4908 X (inches of mercury vacuum) when the atmos- pheric pressure is 14.4 Ib. per sq. in. Table 3 Based on Atmospheric Pressure of 14.4 Ib. Gauge Pressure Absolute Pres- Vacuum Inches Absolute Pres- Ib. per sq. in. sure Ib. per sq. of mercury sure Ib. per sq. in. in. 50 64.4 1 13.91 10 24.4 5 11.95 1 15.4 10 9.49 0.25 14.65 20 4.58 Referring to Fig. 21 in which there are two U gauges, if the closed column B of gauge A is filled with mercury and the gauge is inverted, then gauge A will indicate the pressure of the atmosphere as explained on Page 32. Assume gauge C is an ordinary siphon gauge in which mercury is added until the surfaces of the mercury rest at point E, column D being open to the atmosphere, and columns F and G of the two gauges being connected to the same vacuum pump. When the line leading to the vacuum pump is open to the atmosphere the difference in height of mercury at gauge A will indicate the atmospheric pressure. The elevation of the mercury in the columns of gauge C will be the same, indicating that the pressures on columns G and D are equal. As the vacuum is being placed on the columns F and G thereby removing the air from each of these columns 40 p H Y S ICAL PROPERTIES OF FLUIDS the mercury will fall in columns B and D and rise in columns F and G, for the reason that the pressures acting on columns F and G become less than the atmospheric pressure. The difference in height m of the surfaces of the mercury in the columns of gauge A, will then indicate the absolute pres- sure in inches of mercury acting on the vacuum line. The s A F & _i D Pressure i . Fig. 26 The formula = c is applied to the above figures as follows: Fig. 24 25 26 v T 20 -5-1080 = .0185 ) 10-5- 540 = .0185 5-5- 270 = .0185 Value of c for air at 20 Ib. per j sq. in. absolute. Table 7 Table showing decrease of volume and increase of weight per cubic foot of air, at same pressure as temperature decreases. Temperature deg. fahr. Volume of one Ib. in cu. ft. Weight, Ib. per cu. ft. Absolute Ordinary 1080 540 270 620 80 -190 20 10 5 0.05 0.10 0.20 54 PHYSICAL PROPERTIES OF FLUIDS The fact that the volume divided by the absolute tem- perature is a constant for any certain gas at a certain pres- sure leads to the following statement, v n V ~T n == T ==C in which v n and T n are the conditions at any volume and temperature at the same pressure, then ..-* Let us assume that the volume of a certain weight of gas is 400 cu. ft. at 40 deg. fahr. at a certain pressure. The volume v n at 60 deg. fahr. would be Wn = !!?J! = 400X -416 cu. ft. T 500 Boyle's or Mariotte's Law The volume of a given body of gas depends upon the pressure to which it is subjected. At twice the absolute pressure there is half the volume, while the density and elastic force are doubled. At half the absolute pressure the volume is doubled, and the density and elastic force are reduced to one-half. Hence the law: the volume of a body of gas varies inversely as the pressure, density, or elastic force. This is sometimes called Mariotte's and sometimes Boyle's law, from the names of two men who discovered it at about the same time. This law is true for all gases within certain limits, but under extreme pressure the reduction in volume is greater than indicated by it. The greatest deviation from it occurs with those gases that are most easily liquefied. , The product of the absolute pressure multiplied by the volume of a given weight of gas is a constant. Pv = k where P absolute pressure in pounds per cubic foot. v = volume per pound, in cubic feet. k = a constant depending upon the temperature. 55 PHYSICAL PROPERTIES OF FLUIDS Therefore, at one pound per sq. in. absolute v = k cubic feet. See Table 8 and Figs. 27, 28 and 29. Table 8 Showing increase of volume per pound and decrease of weight per cubic foot of air as pressure decreases at same temperature (80 deg. fahr.) 540 deg. absolute. Pressure Volume in cubic Weight in Ib. Absolute, Ib. per sq. in. Gauge feet of one Ib. of air. per cubic foot. 40 25.6 Ib. persq. in. 5 .20 20 5.6 Ib. persq. in. 10 .10 10 9 in. mer. vac. 20 .05 .. W6.percu.ft. .20Lb. per it. Scvfli Fig. 27 Mume pertf /Ocuff. Fig. 28 SODegfarir per caft .OSit Vo/t/meperlt> ZOcu.fe Fig. 29 The formula Pv = k is applied to the above figures as follows : Fig. 27 28 29 P V 40 X 5 = 200 20 X 10 10 X 20 = 200 .. j deg of k for air at 540 . .. 11, ' fahr ' absolute ' 56 PHYSICAL PROPERTIES OF FLUIDS The fact that the absolute pressure multiplied by the volume of a given weight of gas is a constant, can be ex- pressed as follows : P n v n = p v = k where P n and v n are the new pressures Pv and volumes respectively then v n = ** If the absolute pressure of a certain definite weight of gas is 30 Ib. per square inch absolute and its volume is 120 cu. ft. at 60 deg. fahr. the volume at 20 Ib. per square inch absolute at 60 deg. is Wn = ^ = 30X =180cu, ft. P. 20 Relation between Absolute Temperature and Absolute Pressure As the absolute temperature decreases for a defi- nite volume of gas, the absolute pressure decreases at the same rate and vice versa. That is, the absolute pressure divided by the absolute temperature is a constant or the absolute temperature divided by the absolute pressure is a constant. This is illustrated by the table and diagram following. Table 9 Table showing decrease of pressure as temperature decreases, volume remaining constant. Absolute temp, deg. fahr. Temperature deg. fahr. Absolute Pres- sure Ib. per sq. Gauge Pressure in. 1080 620 40 25.6 Ib. per sq. in. 540 80 20 5.6 Ib. per sq. in. 270 -190 10 9 inch vacuum. 57 PHYSICAL PROPERTIES OF FLUIDS ' we. per cu fC JO It. Wvmepertii /Oct/.ft Fig. 80 ive percuft JOLt>. Vo/vmeperiti /Oct/ft Fig. 31 we per cu ft. /O it>. Vo/umeperib /Ocuft Fig. 32 lOcu. .per The above relation may be shown as follows: Fig. P T 30 40 + 1080 =.037 ' 31 .20 + 540 = .03 7 32 10 + 270=037 Since the pressure divided by the temperature for a cer- tain definite volume of gas is a constant, the relation may be expressed: P P = = a constant T n T In which P n and T n are the new pressures and tempera- tures respectively. If a certain volume of gas at a temperature of 40 deg. fahr. (500 deg. absolute) under a pressure of 30 Ib. per square inch absolute, is heated, the pressure of the same volume of gas at a temperature of 140 deg. fahr. (GOO deg. absolute) would be as follows : P T fiOO P M = " = 30X = 36 Ib. per square inch absolute. T 500 58 PHYSICAL PROPERTIES OF FLUIDS Law of Perfect Gases Let us assume the theoretical vol- ume of a pound of a certain ideal gas at one deg. fahr. absolute under a pressure of one pound per square inch absolute is Z cubic feet; then, according to Charles' Law, the volume increases as the absolute temperature increases, the volume at an absolute temperature, T degrees, will be TZ cu. ft. at one Ib. per square inch absolute pressure. But according to Boyle's Law the volume decreases pro- portionately as the absolute pressure increases, so that if the pressure is increased to a pressure P at an absolute tem- TZ perature J 1 , the volume per pound v = TZ =v P By transposing = Z where P n , v n and T n represent the pressure, volume and tem- perature of the same gas at other conditions than those represented by P, v and T, PvT therefore, v n = - P n T If the volume of a certain weight of gas is 20 cu. ft. at 10 Ib. per square inch absolute at a temperature of 40 deg. fahr., (absolute temperature 500 degrees), the volume at 60 deg. fahr. (520 deg. absolute) under a pressure of 26 Ib. per sq. inch absolute would be P n T 26X500 Therefore, for a unit weight of gas the product of the volume 59 PHYSICAL PROPERTIES OF FLUIDS v multiplied by the absolute pressure P divided by the absolute temperature T is a constant Z. The value of Z for air is 0.37 approximately. for air using one pound the expression becomes a = .37 where P = absolute pressure in pounds per square inch . v a = volume in cubic feet of one pound of air. T = absolute temperature in deg. f ahr. The specific gravity of a fluid is the ratio of the weight of a cubic foot under the same pressure and temperature conditions to the weight of a cubic foot of another fluid used as a standard or base. For gaseous fluids air is gen- erally used as a base and consequently its specific gravity is considered 1.00. For liquids water is used as a base and its specific gravity is considered 1.00 at point of maximum density. Returning to the above formula in which v a represents volume of cubic feet occupied by a pound of air, it can be readily understood that if the specific gravity of a gas is less than air, the volume of a pound is greater proportion- ately than of a pound of air. If v represents the volume of a pound of the gas ^a r- D = ~ or v a = vG G Substituting in the above expression vG for v a , we obtain - = .37 T The product of the absolute pressure in pounds, volume per pound and specific gravity of any gas divided by its absolute temperature, is equal to .37. 60 PHYSICAL PROPERTIES OF FLUIDS = .37JT PG The volume of a pound of gas, at 60 deg. fahr., specific gravity, .60 under a pressure of 14.4 absolute is .37J .37X520 00 , v = = =22.2 cubic feet. PG 14.4X.60 ~D f~* Applying the formula - - in examples given in which air was the gas under consideration, (specific gravity 1.00) the following results are obtained. Constant Pressure. Figs. 24, 25 and 26 PvG 20X20X1 20X10X1 20X5X1 T ~ 1080 540 270 = .37 Constant Temperature. Figs. 27, 28 and 29 Pi)G 40X5X1 20X10X1 10X20X1 T 540 540 540 = .37 Constant Volume per pound or Constant Weight per cubic foot. Figs. 30, 31 and 32 PvG 40X10X1 20X10X1 10X10X1 1080 540 270 =.37 It is noticed that if the value of any term in this char- acteristic equation is changed the value of one or more of the others must change. A clear understanding of this equation and its derivatives will eliminate most of the troubles now experienced in the application of the various factors used in measurement of gases. The only term in this equation which cannot be readily determined in the field is v. Its value can easily be calculated, and even so, its value is not generally required. 61 PHYSICAL PROPERTIES OF FLUIDS PRESSURE DUE TO HEAD OF GAS Due to the universal expansibility of gas, in order to keep the gas from diffusing it is necessary to confine it in an in- closed vessel. Let the vessel ABCD be filled with air at atmospheric pressure. Due to the light weight per cubic foot it is generally assumed that the weight of a cubic foot at the top of the vessel would be the same as the weight of a cubic foot at the bottom of the vessel. This statement is not strictly true for the reason that the air itself weighs something, and the weight of the upper layers tend to compress each lower layer. Assuming that the air is uniform in density, and that the pressure acting on the air by the walls of the container is equal to the atmospheric pressure, the pressure acting on the surface CD would be equal to the pressure on the surface AB which is the pressure acting on the gas at AB plus the weight of the air contained in the vessel, so that on each square inch of surface CD, the pressure is equal to the pressure per square inch acting at AB plus the weight of a column of the air one inch square AC in height. Fig. S3 Air at atmospheric pressure weighs approximately ^ of a pound at 60 deg. fahr. so that if AC is 1872 feet the pressure acting on each square foot on the surface CD is 144 pounds greater than the pressure per square foot on AB or one pound per square inch greater than on AB so that 1872 feet head of air is equal to one pound per square inch or 144 pounds per square foot. Therefore, the head of gas may also be ex- 62 PHYSICAL PROPERTIES OF FLUIDS pressed in pounds per square inch or the pressure in pounds per square inch may be expressed in feet head of gas (at a certain pressure and temperature of the gas). Pressures and Gas Heads From the preceding articles it is evident that the pressure head of any fluid may be expressed in terms of head of any other fluid or it may be expressed in terms of weight per square inch. The units of weight used throughout this vol- ume are (unless otherwise stated) 1 cubic foot of water at 62 deg. fahr. weighs 62.355 Ib. per sq. inch. 1 cubic foot of air at 60 deg. fahr. at 14.7 Ib. pressure weighs .076381 Ib. per cubic foot. Therefore, a column of water one square foot in area, one 62 355 foot high, is equal to or 816.37 feet of air at 60 deg. .076381 fahr. at 14.7 Ib. per square inch, one square foot in area. In- asmuch as air or any gas increases in volume as the absolute pressure decreases, one foot of water will equal 816.37X14.7 or 12000 feet of air at 60 deg. fahr. at one pound absolute pressure. Therefore, one inch of water is equal to 1000 feet of air at 60 deg. fahr. at one pound per square inch absolute pressure. From the laws of perfect gases, for any other pres- sure one inch of water is equal to - in which P is the ab- solute pressure in pounds per square inch. For any other temperature than 60 deg. fahr., since the volume of air in- creases as the absolute temperature increases, the head in 1 000 T feet of air would equal X in which T would be the P 520 absolute temperature in deg. fahr. and 520 the absolute temperature corresponding to 60 deg. fahr. 63 PHYSICAL PROPERTIES OF FLUIDS One inch of water = feet head of air, and since 520P the volume per pound decreases as the specific gravity G 1000 T , increases, one inch of water = - feet of any gas. 520 PG When // = differential in feet head of gas and h = differential in inches of water, 1000 hT ~ 520 PG Example, Gas. Differential, 3 inches of water. Specific Gravity, .80. Atmospheric Pressure, 14.4 Ib. Gauge Pressure, 48.1 Ib. Temp., 60 deg. fahr. Solution: P = 48.1 + 14.4 = 62.5 Ib. per sq. in. abs. T = 60+460 = 520 deg. fahr. abs. 1000 hT 1000X3X520 3 inches of water = - = - =60 ft. head 520 PG 520X62.5X.80 of gas at the temperature and pressure stated. VELOCITY HEAD OF FLOWING GASES Just as the velocity of efflux through an orifice is pro- portional to the differential pressure between the liquid pressures on the two sides of the orifice, expressed in feet head of flowing liquid, the velocity of the flow of gases obeys the same laws in that in which case H is the differential in feet head of flowing gas at the pressure and temperature existing either at the in- let side or the outlet side of the orifice. In orifice meter measurements the percentage differences between these pressures are very small. With some types of connections the upstream pressure is used and with the other types the down- stream pressure is used. 64 PHYSICAL PROPERTIES OF FLUIDS As an example of the theoretical flow of gas at 60 deg. fahr. assume a container of air, the pressure on the upstream side of the orifice as 50 Ib. per square inch absolute and the pressure on the downstream side as 49.82 Ib. per square inch. Then the difference in pressure is .18 Ib. or 5 inches of water (.18X27.71 5). One inch of water equals 1000 or 20 feet of air at 50 Ib. absolute pressure, at 60 deg. fahr. Therefore # = 20X5 inches of water or 100 feet head of air, and V= V2gX100 or 7 = 80 feet per second as the theoretical velocity of the air, each cubic foot passing the orifice at 50 Ib. absolute pressure, at 60 deg. fahr. Fig. 34 65 PHYSICAL PROPERTIES OF FLUIDS Ilk* Out CM* uated to 50 inche* of Water Differential Preure. Grad- uatioru L16 Inch which per- Tap for By-Paw and Connection with down ttream .ide of Orifice. x Double prenure hart, with Differential pre.- Graduationi printed in italic printed in black ink. Fluted iro, Nearly frictionlcw. N Two inch pipe thread for pipe standard over p,pe line. Fig. 35 SECTIONAL VIEW OF A 50 INCH DIFFERENTIAL GAUGE CONCENTRIC CHAMBERS 66 PART THREE ORIFICE METER MEASUREMENT GENERAL ORIFICES DETERMINATION O F ORIFICE COEFFICIENTS MEASURING FLOW OF FLUIDS DIFFERENTIAL GAUGES ACCURACY OF ORIFICE METER DIFFERENTIAL GAUGE CAPACITIES DIFFERENTIAL RANGE PRESSURE CONNECTIONS OR TAPS PRESSURE LOSS PULS- ATING FLOW INSTRUCTIONS FOR METER AT- TENDANTS AND TESTING APPARATUS. GENERAL In determining the flow of fluids (gases, vapors, or liquids), through pipe lines two general types of meters are used, the direct or displacement type and the indirect or velocity type. Displacement meters are installed for measuring ordi- nary rates of flow under low or high pressure, especially of gases and vapors. The velocity type is generally used for measurement in large capacity lines under high pressure. The most familiar forms of displacement meters are the domestic gas meter, the water meter and the station meter. The proportional meter also belongs to this class although it measures only a definite percentage of the flow by displace- ment. The operation of the direct type consists of auto- matically filling and emptying a space of definite volume, counting the number of times the space is filled and emptied by means of gearing, indicating the result in cubic feet, gallons, pounds, etc. The velocity type includes the Pitot Tube with all of its variations, and the Orifice Meter, in which the flow is de- termined by the simple fact that the volume flowing is equal 67 ORIFICE METER MEASUREMENT to the area of a section multiplied by the rate of flow or velocity through this section. For example, if the rate of flow of a gas or liquid through a pipe line whose area is one square foot is 3000 feet per hour the volume passing any point through the line per hour is equal to the area of the cross section of the pipe (l sq. ft.) multiplied by 3000 feet or 3000 cu. ft. per hour. Of the velocity type the Orifice Meter has become the most widely known on account of its adaptability, simplicity and accuracy. An orifice meter will measure the flow of any gas, vapor or liquid of fairly uniform gravity at high pressure or under a vacuum. In fact, they are used successfully for many kinds of gases and liquids such as Natural Gas, Casing- head Gas, Manufactured Gas, Coke Oven Gas, Pintch Gas, Compressed Air, Steam, Water and Oil. The orifice disc or meter is simply a machined circular plate one-fourth inch in thickness having an orifice or circu- lar opening in the center of the plate. For cross section see Fig. 36. *e Fig. 36 SECTIONAL VIEW OF ORIFICE DISC The meter is installed by placing the orifice disc between two flanges or in a body casting in a pipe line with the center of the orifice in the center of the pipe, and connecting the Static and Differential Pressure Gauge with quarter inch pipe to two taps in the pipe or flanges, one on each side of the orifice disc. The accuracy of the meter depends only upon the ma- chining of the orifice disc which can be done easily with extreme precision. Any small pebbles or accumulation of 68 ORIFICE METER MEASUREMENT dirt or rust in the pipe do not produce an appreciable effect on the results; whereas, in the other meters of the velocity type any obstruction equivalent to only a very small per- centage of the area of the pipe affects the accuracy to a large extent. For each installation the orifice in the orifice disc, when placed in the pipe line, forms a definite section of unchanging area, and creates a definite difference between the static pressure of the fluid on the upstream side of the orifice, and the static pressure of the fluid on the downstream side of the orifice, for each velocity or rate of flow of the fluid,* at the same density. This difference in static pressures is termed the differential pressure or the "differential." In other words the "differential," and static pressure, in cases of gases and vapors, indicate the velocity. The Differential and Static Pressure Gauge records on a chart the differential pressure existing between the pressure connections, and the static pressure at one of the connec- tions. These factors with the known area of the orifice enable the operator to determine the flow by multiplying the Pres- sure Extension by the Hourly Orifice Coefficient. The layout of an orifice meter installation may be indi- cated as in Fig 38 where M and F represent static pressure gauges attached to the upstream connection at U and down- stream at D respectively. The pressure connections are also attached to a U tube, upstream at H, and downstream at L. When there is no flow through the line the two gauges will register the same, but when a flow exists it will be observed that the gauge at M will register more than the gauge at F; also that the pressure at H being greater than at L will cause the liquid in column H to lower and in column L to raise. The difference in the level of surfaces of the liquid in the columns being the "differential" h. If the area of orifice is equal * Throughout this volume the term fluids is used to include gases, vapors and liquids and the term gas applies to any gas and air. 69 ORIFICE METER MEASUREMENT 70 ORIFICE METER MEASUREMENT to the area of the pipe, the velocity through it would be the same as in the other adjacent portions of the pipe. If discs having consecutively decreasing areas of orifices are placed in the same line, the velocity of the fluid through the orifices would be increased while the static pressure at the upstream connection would be increased and the static pressure at the downstream connection would be decreased. Downstream Downstream Static Pressure Connect/on \^ Upstream Static '/Pressure Connect ion - 2>irect/on off/ow Fig. 38 DIAGRAM OF ORIFICE METER INSTALLATION The differential pressure between the connections is the pressure creating the flow between the connections. If a series of taps were made in a line of uniform size in which a fluid is flowing, the pressures taken at each of these taps would decrease until at the outlet it would be zero; simi- larly, if two vertical pipes were attached to a line through which water is flowing, one on each side of an orifice, it would be observed that the water on the upstream side of the orifice disc would rise to a higher level than that on the downstream side of the orifice disc. This difference in levels is also the pressure differential, being the same in amount as would be measured by a differential gauge, which is a modified form of U tube using mercury as a liquid. The 71 ORIFICE METER MEASUREMENT Fig. 39 72 ORIFICE METER MEASUREMENT difference in levels between the surfaces of the mercury in the columns of the gauge is indicated on a chart by a pen arm actuated by a cast iron float moved by the rise and fall of the mercury in one of the columns. See Fig. 39. In an actual installation the differential h and static pressure, either at M or F, are usually recorded on the same gauge. Where the pressure connections are made at points 2J/2 diameters upstream and 8 diameters downstream the static pressure at M is recorded, and where the connections are made at the flanges the static pressure at F is recorded, as the published values of coefficients for these two types of connections were determined by using the values of the static pressures obtained in this manner. ORIFICES Gas is being measured by many types of orifices devel- oped by many experimenters. The types generally used are; the thin plates with the cylindrical hole which vary from 1/32 inch to y% inch in thickness; plates of varying thickness from IJ^ inch to J4 inch, drawn down by bevelling at various angles to a thin edge at the circular opening in the center of the plate. Orifice plates are made of such materials as soft iron, coated with German silver to prevent corrosion; mild steel boilerplates; case-hardened or tempered steel. The use of these materials is due to various theories as to the action of gas on the disc. The non-corrosive plating or coating is used on the theory that the principal danger is from change in area of the orifice by corrosion. The use of hardened steel is based on the theory that the principal danger is a change in area from a scouring or sand-blasting of the hole. The mild steel plates are used on the assumption that neither of the two effects mentioned above is a source of serious trouble, but that the important thing is to be able 73 OR IFICE METER MEASUREMENT Fig. 40 THIN ORIFICE USED IN ORIFICE FLANGE Fig. 41 ONE TYPE OF THIN PLATE ORIFICE USED IN ORIFICE BODY, Fig. 1,2 74 ORIFICE METER MEASUREMENT Table 10 ORIFICE CONSTANTS Diameter of Orifice Inches Square of Diameter Inches 2 Area Orifice Sq. Ft. Volume in Cu. Ft. per hour for a velocity of one foot per second 1 A f 8 n .062500 . 140625 .250000 .390625 .562500 . 765625 .000 340 886 .000 766 993 .001 363 54 .002 130 54 .003 067 97 .004 175 85 1.22719 2 . 76117 4.90875 7.66992 11.0447 15.0330 IH IX iy s 1.000000 1.265625 1 . 562500 1 . 890625 .005 454 17 .006 902 93 .008 522 14 .010 311 8 19.6350 24.8505 30.6797 37 . 1224 ix 1^8 1% 1% 2.250000 2.640625 3 . 062500 3.515625 .012 271 9 .014 402 4 .016 703 4 .019 174 8 44.1788 51.8487 60.1322 69.0293 2 2K 2 1 A 2 s /s 4.000000 4 . 515625 5 . 062500 5.640625 .021 816 7 .024 629 .027 611 7 .030 764 9 78.5400 88.6643 99.4022 110.754 m si 6.250000 6 . 890625 7 . 562500 8 265625 .034 088 6 .037 582 6 .041 247 2 .045 082 1 122.719 135.297 148.490 162.296 3 3Ji sy 2 3% 9.0000 10.5625 12.2500 14.0625 .049 087 5 .057 609 7 .066 813 6 .076 699 3 176.715 207.395 240.529 276.117 4 4K *H 4M 16.0000 18.0625 20.2500 22.5625 .087 266 7 .098 515 9 .110 447 .123 060 314.160 354.657 397.609 443.015 5 5K 5K 5% 25.0000 27.5625 30.2500 33.0625 .136 354 . 150 331 .164 989 . 180 328 490.875 541.190 593.959 649 . 182 6 6K 6H 6M 36.0000 39.0625 42.2500 45 . 5625 .196 350 .213 054: .230 439 .248 506 706.860 766.992 829 . 579 894.620 7 IK 7i^ 7M 8 49.0000 52.5625 56.2500 60.0625 64.0000 .267 254 .286 685 .306 797 .327 591 .349 067 962 . 115 1032.06 1104.47 1179.33 1256.64 8K 83^ 8% 9 68.0625 72.2500 76.5625 81.0000 .371 224 .394 064 .417 585 .441 788 1336.41 1418.63 1503.30 1590.44 75 ORIFICE METER MEASUREMENT to machine the orifice to an exact micrometer dimension -so that the capacity can be determined by measurement of the orifice and a predetermined coefficient can be used without individual calibrations for each disc. The principle is self- evident, that more accurate calibrations can be made for a determination for the purpose of establishing a standard for all meters than is possible in individual calibrations for each Fig. 42 SECTIONAL VIEW OF AN ORIFICE METER BODY individual meter. Those advocating case-hardened orifices or orifices requiring individual calibration believe that corro- sion and wear are more dangerous to accuracy than possible variations in individual calibrations. 76 ORIFICE METER MEASUREMENT DETERMINATION OF ORIFICE COEFFICIENTS For Connections 2J/ Diameters Upstream and 8 Diameters Downstream There are several methods of taking differential pressures on the two sides of the orifices, each producing different values of the coefficients. It is the intention of the author to carefully explain the complete methods used in obtaining the coefficients found on Pages 173 to 184. Due credit should be given not only to the Wichita Pipe Line Co. of Bartlesville, Okla., but to A. J. Discher, formerly General Manager, F. P. Fisher, formerly Assistant General Manager, and to E. O. Hick- stein, who carried out the actual tests. Primarily, it might be said that the work was started by the Wichita Pipe Line Co., whose permission was obtained for the publication of the coefficients in the first edition of this book. Other companies have since checked these co- efficients and very little necessity for revision has been found. While Mr. E. O. Hickstein was the engineer in charge of all tests, he was ably assisted by other engineers in the work. Every facility was given the corps of engineers in the above work. Such equipment as artificial gas holders and high pressure pipe lines of several miles in length were used. The work was not accomplished in a few weeks or months, but covered a period of several years, and not until the coefficients had been in use for two or three years were they published. Later tests were made using a 2200 cubic foot holder enclosed within a building. These were known as the Erie tests, and were made at the Plant of the Metric Metal Works. The author was present during these tests which required about one month's time. 77 ORIFICE METER MEASUREMENT The work was done in 1913 and cannot be said to be completed at this writing. However, in 1915 sufficient work had been done to warrant placing the coefficients before other gas companies for their use as well as criticism. JOPLIN HOLDER TESTS* "The discs tested by the method to be described are machined out of . quarter-inch boiler plate or tool steel. The edge of the orifice proper is flat for A in. to i in. and bev- elled at 45 deg. for the remainder of the thickness of the plate. The ordinary practice in orifice meter installations is to have the gauge line connections right at the flange, that is, the inlet and the outlet pressures are taken within an inch or two of the orifice disc, through holes drilled into the companion flanges. In this particular, the meters of the type tested by the author show a departure from the com- mon practice. In the meters tested, the high pressure con- nection was two and a half times the diameter of the pipe line ahead of the orifice disc, and the low pressure connection was eight times the diameter of the pipe line behind the disc. This means that in an orifice meter installation on a 10 in. line, for example, the high pressure connection is 25 in. in front of the disc, and the low pressure connection 80 in. behind it, regardless of the size of. the orifice in the line. It was found by experiments made at Charlottenburg some eight years ago (1907), that, for any flow through an orifice disc not giving an excessive drop in pressure, pressure connections at just the distances mentioned above would give a smaller pressure drop across the disc than would con- nections placed at any nearer position to the disc. There can hardly be any doubt but that the inserting of an orifice disc in a pipe line would cause eddies, and while there is no *Extracts from "The Flow of Air through Thin Plate Orifices," by E. O. Hick- stein, Jun. Am. Soc. M. E. Presented at the Annual Meeting of the American Society of Mechanical Engineers, Dec. 7-10, 1915. 78 ORIFICE METER MEASUREMENT evidence to show that the presence of eddies would affect the accuracy of any measurement through the disc, it was thought best to eliminate this source of possible uncertainty. Derivation of Orifice Meter Formulae for Flow of Air* The fundamental formula for flow through an orifice is r=c,v~2~Tff [i] where V = velocity of flow through the orifice, ft. per sec. C v = so-called "velocity coefficient," varying with the size and shape of the disc. This constant is also known sometimes as the "efficiency," though this term is misleading. g = acceleration due to gravity, ft. per sec., per sec. H = drop in pressure through the orifice disc, expressed in feet of head of the fluid flowing, at temperature and pressure conditions of flow. In this fundamental formula, the differential drop across the orifice is given in terms of feet head of fluid. The differ- ential pressure gauges used in commercial meter installations are nearly all graduated to read in inches of water drop in pressure. It is necessary, therefore, to derive from the funda- mental formula an expression in which the drop is in terms of inches of water. This can readily be done, as follows: Assuming air as the flowing fluid, the fundamental formula [1] can be written - ^^-..JTT*.. ..[2] where Q\= volume of fluid (air in this case) flowing per 15 min., in cubic feet at pressure and temperature P and T respectively (the conditions at inlet of orifice) d = diameter of orifice, in. C v , g and H as in the fundamental formula [1]. "The subscripts in this article have been changed by the author to conform to the remainder of the book. 79 ORIFICE METER MEASUREMENT To reduce the value Qi, which expresses volume at tem- perature and pressure conditions of flow, to Q, the volume at the standard conditions of temperature and pressure (call T b and P b the standard conditions) , it is only necessary to apply the perfect gas law. This is done by multiplying the right-hand side of equation [2] by PT b /P b T. The drop in head, H, now expressed in feet of fluid at P and T, must be reduced to inches of water, as explained above. Kent gives 1 ft. of air at 32 deg. fahr. as equal to 0.015534 in. head of water at 62 deg. From this, one foot head of air at P and T is equal to (0.015534 P 492) -r- (14.7 X T) inches head of water at 62 deg. Formula [2] can now be written : 0_c, w ~ ^ *~ r I 2gA.14.7 T 4X144 P b T ; V 0.015534 X492XP-" and then simplified to ^ ~ jPfr * \ ~~T ^ Formula [41 is the general formula for calculating the flow of air through an orifice disc. A further simplification of this formula is practicable, however, for commercial pur- poses. As the temperature of the flowing gas is not usually measured, an average value is assumed. This is taken in Oklahoma as 60 deg. fahr. The pressure and temperature standards are definite, being usually fixed by contract. All these values, together with d, the diameter of the orifice, can be assembled into one constant, which reduces formula [4] to Q = C a V h P [5] where C a is the so-called "air constant," found experimentally. Orifice Meter Formulae for Gas The orifice meter formulae for flowing gas are derived by the same steps as those for flowing air. In the reduction of H (the differential of the fundamental formula expressed 80 ORIFICE METER MEASUREMENT in feet head of the fluid) to h (the differential in inches of water) the density of the gas must be considered. If the specific gravity of the gas be taken as G, where air equals unity, the general formula for the flow of gas through an orifice meter becomes G T This formula corresponds with formula [4] for flowing air. The simplified commercial formula for a gas flow becomes e=7^VT^ rc s JTT ,...,,..[7] where C g is the so-called "gas coefficient," the meaning of which will be explained. This formula corresponds with formula [5] for flowing air. Formula [7] is the formula actually used in commercial measurement. The values of P and h are shown by the recording pressure and differential pressure gauges, and C g is mathematically derived from the constant of the disc as found by experiment. From the two readings and the gas coefficient, the delivery through the meter can be calculated. Relationship Between the Constants, C v , C a and C g As a rule, the theoretical velocity coefficient, C v , is not used in calculating deliveries through an orifice. Its useful- ness lies principally in the mathematical analysis of the formulae and for purposes of comparing experimental data of tests made under widely differing conditions. C a , the air constant, and C g , the gas coefficient, are the quantities that are used commercially. The relation be- tween these two, as can be seen by comparing formulae [5] and [7] , is expressed by the equation C g =-^=. ..[8] VG 81 ORIFICE METER MEASUREMENT C a , the air constant, is the value that is experimentally found, and does not vary for any disc, unless the assumed standards are changed. The gas coefficient, on the other hand, being a function of the gravity of the flowing gas, will vary, and the gas coefficients of identical discs would be different if the discs were passing gases of different gravities. Orifice disc calibration tests are therefore usually figured for C , the air constant, and this is the value that is recorded. Whenever a disc is put in line at a measuring station, the gravity of the gas to be measured is found by a test, and the proper gas coefficient calculated. The relation between C v and C a is found by equating the right-hand sides of formulae [4] and [5], and can be expressed as r C, = 11.55-^ [9] General Outline of the Joplin Tests The tests on orifice meter discs to be described in this paper were carried out at Joplin, Mo. The discs were cali- brated against the displacement of air from an old artificial gas holder at that place. The holder was a two-lift holder, water sealed and of 250,000 cu. ft. nominal capacity. Roughly speaking, its dimensions were 90 ft. in diameter by 40 ft. total height. The lower lift only was used in the te,sts; this lift has a capacity of 110,000 cu. ft. The reason for using only the lower lift was the change in pressure of the air in the holder, as one lift seated on the bottom. Of the several original outlets from the holder, all but one were securely blanked. The remaining 12 in. outlet was led into a long building, and connected to a straight run of some 40 ft. of pipe, near the center of which was the orifice flange. The air passing out of the holder went through the orifice disc, and discharged into the atmosphere perhaps 20 ft. beyond. A motor driven blower was used to fill the holder with air previous to each test. 82 ORIFICE METER MEASUREMENT LEAKAGE TESTS ON HOLDER. The first tests made were to determine the rate of leakage from the holder. In order to obtain a fair average, a number of such tests were run at the start, with the holder at varying heights. Leakage tests were also run at intervals throughout the whole work, to make sure that the leakage figure first obtained had not materially changed. The first leakage tests (run during August, 1913) were unsatisfactory on account of the large difference between temperature conditions at the start and finish of test. To avoid this difficulty, tests of 24 hours duration, starting at about midnight, were made, and better results obtained. The average of three long leakage tests showed 103 cu. ft. leakage per hr. The correction used in all the Joplin tests was taken as 100 cu. ft. per hr. The result of later leakage tests showed practically the same leakage as the above average, the highest value in any 24 hr. test being 115 cu. ft. per hr. CHANGES OF VOLUME IN HOLDER WITH TEMPERATURE VARIATION. During the leakage tests, it was noticed that the rise and fall of the holder with temperature changes was a greater factor than had been anticipated. A 4 ft. rise from midnight to noon was not uncommon during the hot weather. It was necessary, therefore, to ascertain very accurately the proper correction to apply for temperature changes taking place during a test. Table 11 shows observations and calculated results made in a test run for this purpose. The holder was filled to about three quarters capacity and allowed to stand, hourly read- ings being taken of all quantities involved. The so-called "top" temperature is the reading found by lowering a ther- mometer 2 ft. or so into the holder through a bolt hole on top. From the data the net change in volume due to tem- perature variation for each hourly period was calculated. It was found that the changes in volume as observed were 83 ORIFICE METER MEASUREMENT Table 11 Readings and Calculated Results of First 24 Hours Test on Gas Holder for Investigating Variation of Volume of Air in Holder with Temperature Change. Change of Volume of Air in Holder Cor- rected for Level of Calculated Same Time Temperatures Water Seal and for Leakage In. Height Calcu- lated "Com- bined" Theoret- ical Change of Volume from Values Corrected for Calculated Temp. Beginning Lag of 81 ' During From of Test % m. Atmos. "Top" Previous Beginnine at Start Hour of Test 6 p. m. 96 103 98% -8K 7 p. m. 93 97 STF &TS 94% 6% 14% 8 p. m. 90 91 -sit 17% 90% 11% 20% 9 p. m. 88 88 -4% -21% 88 15% -23% 10 p. m. 87% 86 2% 24% 87 16% -24% 11 p. m. 86 86 1% 25M 86 17% 25% 12 night 85 85 IIT -26H 85 18% 27% 1 a. m. 84 84 1M -27H 84 20% -28% 2 a. m. 82 83 1% 29^ 82% 21% 30 3 a. m. 81 82 -1% -30^ 81% 23 31M 4 a. m. 80 81 \ l /i 31r6 80% 24% -32% 5 a. m. 79% 80 -1% -32H 79% 25 33^ 6 a. m. 78% 80 - M -33^ 79 25M 34 7 a. m. 80 86 5% 27yf 82 27% 30% 8 a. m. 85% 100 7% 20]I 90% 10% 19 9 a. m. 87% 108 m 94% 5 13M 10 a. m. 92 118 7 _^ 5% 101 4% -3% lla.m. 95 122 7% 1% 104 9% % 12 noon 96 131 5% 6% 108 16% 8% 1 p. m. 98 132 2% 9M 109% 19% 10% 2 p. m. 100% 131% 1 10/4 111 21% 13% 3 p. m. 100% 129 2;nr 12re 110 20 11% 4 p. m. 98% 126 2jf 9% 107% 15% 7% 5 p. m. 97 117 2/4 6 104 9K 1M 6 p. m. 94% 109 -4ft 99% 2 _** Height of top of holder, at start, above water in seal, 421 in. Date of test, August 8-9, 1913. 84 ORIFICE METER MEASUREMENT always greater than a calculation based on the ratio of abso- lute temperatures alone would give. After some little study and debating, it was decided that this was due to the presence of aqueous vapor in the holder. This point has always appeared especially interesting, and therefore deserves fur- ther analysis here. LU.V 29.4 Z9.Z 290 28.8 28.6 28.4 28.2 28.0 278 216 27.4 27.2 27.0 268 -o-~ " -o 1 ~ Q --~, , -<^ ">, ^ \ X \ \ \ \ fapor Tension af the differen Temperatures, deducted fron Total Holder Pressure. Circles indicate Points fauna by Computation / \ 7 \ r \ \ \ \ * ""TO 30 40 50 60 70 80 90 100 110 12 Fig. Temperatura of Holder Air,Deg Fahr. 43 CALCULATED "GAS PRESSURE" IN HOLDER WITH VARYING TEMPERATURE That saturated water vapor was present in the holder air is evident. By Dalton's Law, it is correct to assume that the pressure inside the holder is made up of two distinct quantities (a) the tension of the saturated aqueous vapor, (b) the pressure of the air in the holder. The sum of these two component pressures, expressed as absolute, will be the barometer reading plus the reading of a U tube connected up to the holder pressure. Therefore, for a constant baro- 85 ORIFICE METER MEASUREMENT meter, the total pressure of the holder will not change. If, however, the temperature should rise while the barometer remains constant, the tension of the saturated vapor will increase, and the second component of the total pressure, the pressure of the air (which will be called the "gas pressure" in this connection) must be correspondingly decreased. With varying barometer readings, this change in value of each component pressure will be different. However, a very close approximation can be had by basing all corrections on the average barometric reading at Joplin, viz., 29.3 in. 1.180 1.160 1.140 1.120 I.KX) 1.080 1.060 LWO 1.020 1.000 0.980 0.960 0540 0.9ZO 0300, i / i Circles indicate Points found by Computation. Volume at 70 Deg.Fanr assumed as Unity (Line A) Volume Variation by"Boy!es"Lan shown by Curve & i 7J / / / ,-- / 5 ^ / ^^ ,** / j? ^^ / ^ r "*' A *'l r ^" ^ r ^*- / s ^^' * Lx" ys ft r 30 40 50 60 TO 80 90 100 110 12 Temperature of Air,Deg.Fahr. Fig. 44 CALCULATED VARIATION IN VOLUME OF AIR ENCLOSED IN HOLDER OVER WATER, WITH CHANGE OF TEMPERATURE For any temperature, the second component of the total holder pressure the gas pressure can be found by subtracting from the total holder pressure the vapor tension for the temperature. The total pressure is the assumed 86 ORIFICE METER MEASUREMENT barometric reading, 29.3 in., plus the observed pressure of the holder, 4.60 in. of water. The vapor tension for varying temperatures can be found in any handbook. Fig. 43 shows the variation of the gas pressure in the holder for temperature changes. The circles indicate points found by computation, and through these the curve is drawn. 15 10 5 -5 HO -20 .-25 -30 -35 Points joined by Solid Lines indicate Actual Rise and. faJf. Points joined by Dotted 'Lines indicate Theoretical Rise and fall O L- (3J O >H !H : | <3o O fe cj 5 "~* T5 *S *S a *- d D rt bfl 5n >H ^ rt a ,2 D -*- 1 -*- 1 H g 33 S, . i "^ d p t ^ GJ ^ <^ > rt as < 02.4H ^< 00 o| d | .00 OOC 3 OOO OOO OO o 1-1 r-c G 53 ^ f ! T s T i ^-< d Su 6 ^ ^^ \ ^ ^^! ^^ O C C 3 LOOLO LOOiO OO CM r}< CO 00 OS C 3 CMCOLO b-OOO CMCO H OOSOO b-CDCD LO^t* P4 C\J ^ \O^XN N^V^ ?i ' o 0*1 PH t j CO LO LO ^ <* T CO CO CO CO CO Ci < CO CO CO CO CO CO CO CO 2 CO CO CO CO CO CO CO CO s < ft .\N \N . . \cq . S H CO CO rj< CO CO -CO rH\ -\ CO CO CO CM CO CD CO CO PH S W ' t/3 \M \C^\N\N \N H i 8,496 4.41 29.2 70 iQy 2 0.532 216 8201 6 4 }/2 3,579 4.52 29.2 68 65 0.2234 217 8201 7 4^| 2,575 2.37 29.3 69 65 0.2217 218 8452 Nov. 3 2 18,989 3.37 29.4 58 55 1.387 219 8452 3 2)4 18,772 3.42 29.4 57 54 1.358 220 8452 4 2 18,970 3.44 29.5 57 52 1.372 221 8452 4 2 18,791 3.44 29.5 55 49 1.361 222 8502 5 2 23,099 2.81 29.45 57 52 1.841 223 8502 5 iy 2 23,215 2.82 29.45 56 50 1.853 224 8502 5 1 1 A 23,375 2.80 29.45 55 50 1.879 225 8201 6 5 3,641 4.52 29.3 60 59 0.2274 226 8301 11 3^ 8,166 4.33 29.35 59^ 5sy 2 0.521 227 8301 12 sy 2 8,248 4.34 29.35 64 65 0.520 228 8502 13 2 23,485 2.80 29.4 63 64^ 1.852 229 8201 14 5 3,566 4.53 29.45 64^ 64^ 0.2248 230 8201 15 4 3,560 4.585 29.3 54 49 0.2242 231 8352 Dec. 5 3 11,257 4.10 29.4 59 56 0.742 232 8601 6 \y 2 31,267 1.70 29.2 55^ 46 3.273 233 8352 5 4 11,241 4.18 29.1 55^ 48 0.746 92 ORIFICE METER MEASUREMENT Table 14 Summary of Holder Tests on 8 in. Orifice Meters Test No. No. of Meter Disc Date of Test and Duration in Hr. Avg.Corr. Rate Cu. ft. in 30 min. U-Tube Read- ing, In. Water Baro- meter In.Mer cury Observed Temp. Calc. Ca Flow "Com- bined" 234 8601 7 iy 2 30,478 1.65 29.5 51 33 3.293 235 8352 6 3 l / 2 11,310 4.09 29.2 55 46 0.762 236 8601 7 1 1 A 30,463 1.65 29.5 51 31 3.306 237 8353 5 4^ 11,161 4.08 29.4 59y 2 56 0.738 238 8502 7 1 1 A 22,758 2.90 29.5 50 30 1.866 239 8601 30 iy 2 36,548 2.355 29.3 47 3234 3.305 240 8551 30 iy 2 31,023 2.99 39.3 48 33 2.487 241 8551 31 iy 2 30,942 3.00 29.2 50^ 37 2.467 242 8571 31 iy 2 33,982 2.665 29.2 49 37 2.871 243 8571 Jan. 1 iy 2 29,408 1.965 29.0 53^ 46^ 2.865 244 8601 i iy 2 31,093 1.64 29.0 53 45 3.32,5 245 8551 1 1^2 27,337 2.30 29.0 52 4034 2.485 246 8352 2 zy 2 10,969 4.13 29.3 48^ 30 0.752 247 8352 2 zy 2 11,148 4.31 29.3 48 27^ 0.752 248 8551 3 iy 2 26,775 2.285 29.3 48^ 3134 2.468 249 8601 3 iy 2 30,503 1.615 29.3 49^ 32 3.344 250 8571 3 iy 2 28,495 1.96 29.3 48^ 28!4 2.853 251 8521 Feb. 16 iy 2 28,108 3.13 29.4 49 42 2.163 252 8251 18 3 5,684 4.62 29.1 47^2 35^ 0.3653 253 8251 19 zy 2 5,536 4.51 29.3 49 35 0.3599 254 8521 19 iy 2 28,075 3.22 29.3 47^ 35 2.162 255 8151 20 9 1,877 4.63 29.4 5234 31 0.1216 256 8151 21 5y 2 2,144 4.63 29.7 56 49 0.1338 257 8151 23 9 1,802 4.61 29.6 46 12^ 0.1196 258 8305 Mar. 4 3 8,101 4.49 29.4 5234 36 0.5275 259 8506 6 iy 2 23,425 3.00 29.5 4934 35^ 1.865 260 8506 9 iy 2 23,617 2.96 29.4 5234 44 1.867 261 8473 25 iy 2 22,375 3.30 29.35 5sy 2 64^ 1.615 262 8474 25 iy 2 21,985 3.28 29.35 59 6434 1.595 263 8473 25 iy 2 22,162 3.28 29.4 59 Q2 1 A 1.615 ORIFICE METER MEASUREMENT Table 15 Summary of Holder Tests on 8 in. Orifice Meters Test No. No. of Meter Date of Test and Duration Avg.Corr. Rate Cu. ft. U-Tube Read- ing, In. Baro- meter In.Mer Observed Temp. Calc. Disc in Hr. in 30 min. Water cury Flow "Com- Ca bined" 264 8474 Mar. 25 \Y 2 22,045 3.27 29.4 59 63 1.607 265 8251 26 5 5,655 4.51 29.4 59 59 0.3532 266 8151 27 V/2 2,048 4.59 29.35 63 59 0.1274 267 8251 30 6 5,780 4.52 29.4 62 63 0.3603 268 8151 April 1 QY 2 2,161 4.64 29.5 62 56^ 0.1339 269 8251 2 5 5,590 4.50 29.5 61 59 0.3479 270 8171 6 5 2,742 4.62 29.3 59 55^ 0.1696 271 8171 7 ey 2 2,564 4.61 29.55 54 36K 0.1644 272 8171 8 8 2,553 4.62 29.65 54 29 0.1658 273 8171 9 6 2,513 4.61 29.5 55 34^ 0.1622 274 8151 18 6y 2 2,000 4.61 29.4 59 52 0.1253 275 8151 19 6 1,866 4.60 29.45 59 44 0.1188 276 8151 20 QY 2 1,998 4.59 29.4 64 60 0.1238 This corrected value of the quantity of air discharged, reduced to standard conditions of temperature and pressure, corresponds with the value Q in formula [4] . In this formula, as all the quantities but C v are known, the latter can be calculated. The relation between C v and C a , as shown by equation [9], gives a means of obtaining this latter value. As stated earlier in the paper, the 15 min. air constant was the value calculated in all the Joplin tests. C a is expressed in thousands of feet for 15 min. Summary of Results of Tests About one hundred and sixty tests on 8 and 10 in. orifice meter discs were run at Joplin during 1913-1914. A summary of the results of these tests is included in Tables 13 to 17 inclu- sive. A note on the system used in numbering the discs will make the summary self-explanatory. The first one or two 94 ORIFICE METER MEASUREMENT Table 16 Summary of Holder Tests on 10 in. Orifice Meters Test No. No. of Meter Disc Date of Test and Duration in Hr. Avg.Corr. Rate Cu. ft. in 30 min. U-Tube Read- ing, In. Water Baro- meter In.Mer cury Observed Temp. Calc. Ca Flow "Com- bined" 401 10401 Dec. 20 3 13,978 4.345 29.4 48 32 0.9286 402 10501 20 2 23,156 3.94 29.5 47 32^ 1.611 403 10501 20 2 23,138 3.94 29.4 l&A 31 1.620 404 10801 26 1 53,855 1.38 29.4 45 2&A 6.384 405 10751 21 1 49,513 1.89 29.5 48 333^ 4.983 406 10801 21 1 53,975 1.38 29.3 50 35 6.370 407 10801 22 y 2 55,595 1.43 29.2 48 36 6.429 408 10751 22 1 50,575 1.95 29.2 49 35 5.025 409 10501 23 2 23,209 3.95 29.2 49 32^ 1.626 410 10401 23 33^ 14,189 4.38 29.2 48 33 0.9406 411 10551 22 iy 2 29,042 3.89 29.2 48 35^ 2.035 412 10551 26 iy 2 28,225 3.68 29.4 45 26K 2.055 413 10751 27 1 48,850 1.90 29.4 48 363^ 4.976 414 10801 27 % 55,220 1.39 29.4 49 37 6.450 415 10501 27 2 21,080 3.28 29.4 49 35^ 1/605 416 10701 28 1 45,038 2.41 29.5 46^ 35^ 3.986 417 10401 Jan. 5 3 13,990 4.31 29.4 4sy 2 28^ 0.9355 418 10801 5 1 53,363 1.37 29.5 47 2sy 2 6.368 419 10501 6 2 23,076 3.89 29.3 49^ 39 1.604 420 10651 6 iy 2 39,034 2.87 29.3 50 40 3.159 421 10551 7 iy 2 28,593 3.65 29.1 53^ 493^ 2.025 422 10601 7 VA 34,335 3.27 29.0 54 483^ 2.581 423 10751 7 1 50,320 1.89 29.0 55j^ 473^ 4.997 424 10551 s iy 2 28,457 3.63 29.0 52^ 46 2.035 425 10601 s iy 2 34,028 3.24 29.0 49 W 1 A 2.613 426 10601 s iy 2 34,105 3.25 29.0 51^ 43 2.592 431 10771 17 1 50,952 1.61 29.3 5iy 2 44 5.474 432 10351 1733^ 10,890 4.39 29.3 53 44^ 0.7067 433 10601 is iy 2 34,250 3.31 29.0 52 44 2.578 434 10601 20 iy 2 33,983 3.27 29.2 52 42^ 2.571 435 10451 20 2y 2 18,172 4.16 29.2 50 38^ 1.224 436 10651 20 1 38,922 2.91 29.2 49 33 3.174 437 10351 22 sy 2 11,028 4.44 29.0 57 57 0.7003 95 ORIFICE METER MEASUREMENT Table 17 Summary of Holder Tests on 10 in. Orifice Meters Test No. No. of Meter Disc Date of Test and Duration in Hr. Avg.Corr. Rate Cu. ft. in 30 min. U-Tube Read- ing, In. Water Baro- meter In.Mer cury Observed Temp. Calc. Ca Flow "Com- bined" 438 439 440 10651 10551 10551 Jan. 22 \y 22 \y 2 23 \y 2 40,104 14,412 14,713 2.92 3.68 3.69 29.0 29.0 29.0 57 55 57 56M 3.147 2.015 2.063 441 442 443 10751 10701 10701 23 1 23 1 24 1 25,288 45,510 44,938 1.91 2.39 2.35 29.0 29.0 29.2 53 52 47^ 46 40^ 34 5.001 4.061 4.076 444 449 452 10801 10351 10451 24 1 28 3 1 A 31 zy 2 53,895 11,101 18,329 1.36 4.44 4.23 29.2 29.0 29.4 46^ 60 62 36 6.432 0.7003 1.226 454 456 457 10501 10801 10351 Feb. 1 2 2 1 2 3 23,345 53,800 10,805 3.93 1.37 4.37 29.3 29.3 29.3 50 50 51 43 38 40 1.603 6.337 0.7085 458 459 460 10801 10701 10351 3 1 3 1 4 4 53,863 44,560 10,751 1.38 2.40 4.46 29.4 29.4 29.2 48 47 47 33 30 6.361 4.009 0.7074 461 462 463 10771 10771 10551 4 1 6 1 51,580 51,187 27,538 1.64 1.65 3.76 29.2 29.4 29.4 44 39 39 31M 5.590 5.695 2.054 465 466 467 10621 10621 10621 11 \y 11 iM 36,934 36,742 36,818 3.12 3.11 3.10 29.3 29.3 29.3 53 48M 46 2.825 2.818 2.836 477 478 479 10301 10301 10252 April 21 6 22 6 23 7 4,059 4,056 2,735 4.49 4.47 4.52 29.4 29.5 29.4 64 65 64 67 67 0.5019 0.5102 0.3380 480 481 482 10301 10252 10252 25 6 1 A 26 7 27 7 3,863 2,707 2,745 4.37 4.53 4.57 29.65 29.3 29.25 60 67 63 47 67 62 0.5043 0.3354 0.3409 483 484 485 10301 10301 10301 28 6 29 6 30 6 4,005 3,990 3,931 4.42 4.48 4.49 29.4 29.6 29.6 62^ 62 61 56 53 53 0.5101 0.5089 0.4986 486 10252 May 1 6 2,701 4.53 29.4 62 553^ 0.3412 96 ORIFICE METER MEASUREMENT digits indicate the size of the pipe line in which the disc is inserted; the next two digits, the size of the orifice; the re- maining digits, the serial number of the disc. For example, 8473 represents an 8 in. meter disc, 4J4 in. orifice; 104211 is a 10 in. meter disc, 4^ in. orifice, etc. It was found necessary to discard perhaps half a dozen tests, on account of their disagreeing widely from the averages of the remainder. In two or three of these discarded tests, a shower or a fall of snow during the Itest furnishes a possible explanation; in other tests, no expanation was found. It is worthy of special note that in these tests the stand- ard used is an actual measurable volume, and not a standard- ized pitot tube or other indirect method of measurement. The advantage of being able to calibrate directly against displacement is a most important feature of these holder tests. A second feature of the tests is the ability to auto- matically secure a practically constant flow, without regu- lation of any kind. Another point deserving mention is the fact that dupli- cate discs of sizes already tested at Joplin require no calibra- tion of any kind. It is merely necessary to micrometer the orifice and to correct mathematically for any small deviation from the nominal diameter. For example, if a new 8 in. by 4 in. orifice disc micrometers 4.004 in. in diameter, and the result of the Joplin tests on the master 8 in. by 4 in. orifice be 1.034, the value of C a for the slightly oversized disc would be 1.034 (4.004-^4.000) 2 or 1.036. The possibility of securing constants for duplicate discs without actual calibration is a great advantage, as will be realized. It means that sufficient time and effort can be spent in calibrating the master discs to secure the highest possible accuracy, without having the cost of an individual disc excessively high. That the method of calculating con- stants for new discs as described above is correct has been very well shown by careful checks made at Joplin. 97 ORIFICE METER MEASUREMRNT Comparison of Results with Charlottenburg Tests Indicates Coefficient Values forl Or/f/ce D/3) 1 0" b- A t i (^ f // /< ' Ir tc/tcaf&s Coeffi lues found a f larlotfenburg f if ice Oisks C'er or3 f +7_ / /- V-?- -o x^ &'' Oi ^, /?. f Cot Va 8"C 'ffH ffic 'ues rifi ks /en for ce N ^. && ^. X'V 3 ^^~ 10 20 30 40 50 60 70 80 90 100 Ratio of Pipe Diameter to Orifice Disk Diameter, PerCent. Fig. 47 COMPARISON OF VELOCITY COEFFICIENTS OF ORIFICE METER DISCS, AS FOUND IN JOPLIN TESTS FOR S IN. AND 10 IN. PIPE LINES, WITH VALUES FOUND AT CHARLOTTENBURG Table 18- -Summary of Values Plotted Joplin 8 in. Joplin 10 in. Charlottenburg 3% i n - d/D Cv d/D Cf d/D Cv 0.1875 64.9 0.15 60.1 0.25 63.5 0.219 64.2 0.175 61.1 0.30 64.0 0.25 64.7 0.25 62.8 0.40 65.5 0.3125 66.9 0.30 65.6 0.50 73.0 0.375 67.9 0.35 66.9 0.60 81.0 0.4375 71.1 0.40 67.9 0.70 96.0 0.50 75.3 0.45 70.4 0.75 106.0 0.5625 79.0 0.50 74.9 0.594 82.2 0.55 78.7 0.625 86.6 0.60 83.2 0.655 91.3 0.625 84.6 0.6875 95.3 0.65 86.6 0.7187 100.7 0.70 95.9 0.75 107.0 0.75 103.5 .... 0.80 116.6 ORIFICE METER MEASUREMENT The only published report* of tests made on orifice discs similar to those tested at Joplin gives the values of the velocity coefficient, C v (as used in the fundamental formula) for 3M m - pipe found in tests made at Charlottenburg, Germany. Fig. 47 shows graphically the values found at Charlottenburg compared with the Joplin results for 8 and 10 in. p ipe. The Joplin curves agree fairly well with the Charlottenburg values, especially if the difference in the pipe size is taken into account." ERIE HOLDER TESTS A subsequent series of calibrations was run in 1915 to supplement the large capacity meters previously developed by the addition of a series of relatively small capacity meters in 6 in. and 4 in. pipe. The reference quantity chosen for this work was a small holder located at the testing plant of the Metric Metal Works, Brie, Pa. Check tests were also taken with 8 in. and 10 in. pipe line orifices; in all about 130 determinations were made covering the following orifices. Table 19 No. Size of Pipe, In. Size of Orifices In. No. Size of Pipe, In. Size of Orifices, In. 4051 4 0.506 6204 6 2.002 4071 4 0.755 6302 6 3.003 4103 4 0.996 6401 6 4.000 4123 4 1.250 8101 8 1.010 4154 4 1.500 8205 8 2.006 4174 4 1.754 8304 8 3.006 4205 4 1.997 8451 8 4.500 4223 4 2.251 8506 8 5.005 4251 4 2.504 10151 10 1.500 4301 4 3.002 10302 10 3.007 6101 6 1.002 10451 10 4.502 6151 6 1.502 10601 10 5.999 * Zeit. des Ver. d. Ing., Feb. 23, 1908. 99 ORIFICE METER MEASUREMENT 100 ORIFICE METER MEASUREMENT Table on Page 102 gives data for determination of leak- age in the holder and lines. This gives a leakage correction factor for these tests and the dimensions of the holder. Table on Page 103 is a recapitulation of the derivation of the formula used in determining the air constant in this series of tests. The following is a key to the tabulation employed on the following pages. Column Data 1 Date of Test 2 Size of Disc 3 Barometer in inches of mercury. 4 Feet Drop of Holder, each foot drop is equiva- lent to displacement of 200 cu. ft. 5 Time in Seconds taken by stop-watch. 6 Ph Holder pressure (Ib. per sq. in., absolute). 7 T h Temperature of holder air, deg. fahr. 8 T Temperature of flowing air, deg. fahr. 9 h Differential across disc inches of water. 10 P Absolute pressure, in Ib. per sq. in. on inlet side of disc. 11 C a Fifteen-minute air constant for disc. 12 C v Velocity coefficient per cent. Tables 20 and 21 are specimen sheets showing a summary of determinations made on various orifices in 6 in. pipe. Leakage Test, August 7, 1915 The readings and cal- culated results given here show Leakage Test made to ascer- tain rate of leakage from holder, so proper allowance could be made. This test was started about noon on a Saturday and ran until early Monday morning. Time Start 11:30 a. m. Aug. 7, 1915. Finish 7:00 a. m. Aug. 9, 1915. 101 ORIFICE METER MEASUREMENT Temperature of Reading Readings Holder of deg. fahr. Tape Start 70 26.0 Finish 71 25.85 Leakage (without any allowance for change of temperature during test) : 0. 15 ft. drop in 43J/2 nr - This is equivalent to 0.0115 cu. ft. per min. Leakage (with temperature cor- rection made): 0.0130 cu. ft. per min. Calculated Volume of Holder, August 10, 1915 Measured Diameter of Holder Top (Outside). 16' 0.5"; 16'0.1"; 15'11.8"; 15'11.9"; 15 / 11.7"; 16'0.1"; 15'11.7"; and 16'0.0" Average 15'11.975" Allowance for thickness of metal 2 thickness No. 16 gauge iron 0.125" Inside Diameter or 151 1.850" 15.988 ft. Calculated area = 200. 76 sq. ft. which means that one foot drop of holder displaces 200.76 cu. ft. The nominal capacity is 200 cu. ft. per ft. drop; the actual capacity is therefore /^ of 1 per cent above the theoretical. This error of % of 1 per cent in holder capacity is ignored in the calculation of all tests given in this report. It exactly counter-balances an error of ^8 of 1 per cent in stop watch. Measured Circumference of Holder Near Top ............................ 50'3%" Near Middle ......................... 50'4" Near Bottom ........................ .50'4^/ 102 ORIFICE METER MEASUREMENT Derivation of General Formula for Calculating Holder Tests on Orifice Meter Discs. Q = quantity measured under standard conditions of pressure and temperature, i. e., 60 deg. fahr. (520 deg. absolute) and 14.41 Ib. per sq. in. Subscript h means actual conditions of air or gas in holder. This will vary from day to day, even for the same holder. Assuming Flow Temp, of 60 deg. fahr. = C fl V h P for air, = <*/ \ At any other Flow Temp. T or = <* - for gas. G h PX520 T G Furthermore 520 P L ftx 520 In this general formula derived above, there are sub- stituted special values for reducing quantity and time of test giving. C =284 6 Tape Difference (in ft) Ph l~f Number of Sec. T h \ h P 103 ORIFICE METER MEASUREMENT 10 TH Oi O .g CO CO s (1) H 00 O CM 00 CM i> J> t> co co co co co CD CD CD t> CVJ CO COCOLOOjLOCviCO^CO Oi CO LO LO >- Oi t LO i"H rH LO LO rH LO Oi Oi CO rH CO Oi CO ^ ^ ^ rH rH ,-H rH O O O O CM > I Oi CM Oi 00 CM - I inm-^m mminm in Tf CO CO co io oo Ttf Tj< CO o m t-t~00t>! I r-HCOCO'-Ht I CMOOCOCO CiCOOir^ r-(05CM'-l CM-^rHCO COCMCMCO m^'cOCAJ O5O5O5O5Oii Ir-Hr-li-H CO CO CO CO CO CO 00 in in m . l . l . ( i li l. lr-H.-HCMCMCMCM CMCM CO CO CO CO CO CO 00 CO CO 00 CO 00 00 CO in in in in in in in in in in in in in in 00 00 CO 00 CO 00 00 CO 00 00 00 00 00 CO 00 00 00 00 00 00 CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO o t- m i 1 OJ 00 CO CO lO - ^ 00 ^ O oooo minmin CO CO CO CO CO CO CD CO lO 1 1 t- i-H CVJ CO r- 1 CM CO-^mCD >OOO5O 00 104 ORIFICE METER MEASUREMENT CO CO CO CO CO r-ICOO Ol t- CO CO CO CO CO CO CO CO CD Tt< CO CO CM CO CO lOOOCOCOlOi llO CM CM rH CO >-H CO Tfr* ^ rH CO lO CO CO O O G^ 00 CO CM CM CM CO CO CO CO CO CO CO CO OOOOO OOOOOOO OOOOOOOOO rH rH rH rH OOOb-tO^C^rH ^Ht-COOiOCOiOCOiO CO CO > I O5 CDiOkOkOkOiOiO >COCDiOiOiCiOiOiO CDCDCDkO Q5 tO tO ^ rH Oi Oi O rH 00 CO CO CO tO Qi CVJ CO tO tO 00 rH CO CO tr CVJ t* rH rH O Oi 10 rt< CO CM r-i lO^^OQCOCMCM LO^CM CO 00 CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO tO tO tO tO tO tO tO tO tO tO tO tO tO tO tO tO tO tO cocococgcococg Tj< T^ Tt< Tj< Tj< Tf rf GO lO i i rH lO COCOiOC- r I i i rH lO rHC^JCO 00 CO iOkO OOOOO t- O O O O O CM 05t>0000 t> t> CO CO COCOCOCDCOCOCOCOCO COCOCOCD OiOSOiOSOi O5OiOiO5OiO5Oi C5OiO5O5OlOiCiO5O5 OiOiOiOS OOOOO rH rH rH rH rH CO CO CO CO CO (MCvi(M<>JO3 CO CO CO CO CO TfTf'^ CO CO CO 105 ORIFICE METER MEASUREMENT It will be noted that there are a few minor changes in the coefficients in the Tables in Part 4. These changes are very slight and are caused by some errors in the original work. Status of Coefficient Fig. 50 shows the degree of variation under the con- ditions of the different tests, and the solid black line is an averaging line on which coefficients for actual use at the present time are based. All the orifice calibration work, up to and including the Brie tests, has been compiled and reduced to a basis shown in Pages 108 and 109, showing the "coefficient of velocity" for all sizes of pipe plotted on a basis of the ratio of diameters of orifice to diameters of pipe. Fig. 49 ORIFICE FLANGE METER AND LIGHT PORTABLE DIFFERENTIAL GAUGE, PIPE TAP CONNECTIONS 106 ORIFICE METER MEASUREMENT TESTS Mcer*| TESTS Size OF ORIFI /NCHCS 50 107 ORIFICE METER MEASUREMENT 108 ORIFICE METER MEASUREMENT .55 fi h^4+ frrrr &SO m K m ffttt+fflfewifrp m - mm /.oso 1.000 .850 .800 .750 .70 .75" 109 ORIFICE METER MEASUREMENT It is the belief of the author that this value may be safely applied within the limits of accuracy shown by the curve to any practicable size of pipe line without further question. The number of experiments which are incor- porated in it, and the great variety of conditions under which it has been developed, have practically eliminated any per- sonal equation of observational error of any individual test or series of tests. MEASURING FLOW OF FLUIDS The relation between the differential and the velocity of the fluid through the orifice is expressed by the formula : where V = velocity of flowing fluid in feet per second. g = acceleration due to gravity in feet per sec. H = differential expressed in feet head of flowing fluid. As it is not practical to register this value directly, the differential is recorded on the chart in inches of water pres- sure. C v = Coefficient of Velocity. It is the ratio of the actual velocity to the theoretical velocity of fluid passing the orifice. Its value depends upon the ratio of the diameter of the orifice to the diameter of the pipe, and the location of pressure connections with respect to the orifice. The Coefficient of Velocity is the same for the same ratio of diameter of orifice to diameter of pipe, i. e., the value of C v for a two inch orifice in a four inch pipe* is the same as for a three inch orifice in a six inch pipe or a four inch orifice in an eight inch pipe. These coefficients do not bear a simple mathematical relation to the ratios of diameters but they in- crease as the ratio of diameter of orifice to diameter of pipe * Actual Dimension. 110 ORIFICE METER MEASU RE M E N T increases. A two inch orifice in a three inch pipe has a greater coefficient than a two inch orifice in a four inch pipe. The reason for this is that the nearer the size of the orifice approaches the size of the pipe line the more closely the flow approaches a jet effect and vice versa. With a small orifice in a large pipe the effect produced is nearer that resulting from passing the fluid through a small opening in a drum or storage tank. When the pressure connections are located at the flange the values of the "coefficient of velocity" are lower than when placed farther from the flange. The values of C v for various ratios, diameters of orifices and pipes are given on Pages 108 and 109. They apply for any fluid, whose viscosity is equal to or less than the viscosity of water. As the Hourly Orifice Coefficient varies with the "co- efficient of velocity" it is changed by any change affecting this factor. The following examples illustrate the application of the modified formula V = C v V 2 gH to the flow of various gases and liquids through a pipe line. It is not practical to use this method of computation for routine work but the solu- tion of the examples demonstrate the fundamental princi- ples of orifice meter flow. EXAMPLE Air being measured; atmospheric pressure, 14.4 lb.; line or static pressure, 28.8 lb.; temperature, GOdeg. fahr.; diameter of orifice, 2 inches; diameter of pipe, 4.026 inches; differential, 17 inches of water; pressure connections at 2 J/2 and 8 diameters from orifice. Absolute Pressure P= 14.4+28.8 = 43.2 lb. per sq. in. Absolute Temperature T = 60+460 = 520 deg. fahr. Diameter of Orifice 2.000 Ratio X = = = .497 Diameter of Pipe 4.026 111 ORIFICE METER MEASUREMENT C, for a ratio of .497 = 736 (Page 108). 1000^ T 1000X17X520 H = - = = 394 feet of air at 43.2 Ib. 520PG 520X43.2X1 absolute at 60 deg. fahr. (Page 64.) V = C V ^ 2gH=. 736 V 2X32.16X394 = 117.2 ft. per sec. Area of 2 inch Orifice = .0218 sq. ft. (Page 75) The quantity per second equals the area of the orifice in square feet multiplied by the velocity in feet per second. Quantity =.0218 XI 17.2 = 2.55 cubic feet per second at 43.2 Ib. absolute, at 60 deg. fahr. 2.55X43.2 Quantity based on 14.4 Ib. per sq. m. = 14.4 7.65 cubic feet per second. Quantity per hour = 7.65X60X60 = 27,500 cu. ft. at at- mospheric pressure. EXAMPLE Gas being measured; period, 24 hours; pipe line, 4 inches (actual inside diameter 4.026 inches) ; diameter of orifice, 2% inches; average differential pressure, 54 inches of water; atmospheric pressure, 14.5 Ib.; line pressure, 105.5 Ib.; Pressure Base, 8 oz. above atmospheric pressure ; Base and Flowing Temperature, 60 deg. fahr. Specific Gravity, 0.60; pressure connections at 2^ and 8 diameters from orifice. _, v Diameter of Orifice 2.625 Ratio X = = =.652 Diameter of Pipe 4.026 C v for a ratio of .652 = .901 Page 109. Flowing Temperature = 460 + 60 = 520 deg. fahr. absolute . Static or Line Pressure =105.5 + 14.5 = 120 Ib. per sq. in. absolute. Pressure Base = 0.5+ 14.5 = 15.0 Ib. per sq. in. absolute. 112 ORIFICE METER MEASUREMENT 1000X54X520 __ n , . , , , . H = - = - = 750 feet head of air at 120 520PG 520 X 120 X. 60 Ib. absolute at 60 deg. fahr. Page 64. .901 V 2X32.16X750- 197.9 feet per sec. Area of 2% inch Orifice = .03758 sq. ft. (Page 75) . Quantity per second equals area of orifice multiplied by the velocity =.03758X197.9 = 7.44 cubic feet of gas per second at 120 Ib. per square inch absolute. 7 44 x 120 Quantity, at 15 Ib. per square inch absolute = 15 59.5 cu. ft. per second ; for 24 hours = 24 hours X 60 minutes X 60 seconds X 59.5 cu. ft. per second = 5, 140,000 cu. ft. per day. In these examples it is noted that the differential when expressed in feet head of flowing gas or air is decreased as the pressure increases and that the volume when expressed at a Pressure Base is increased as the static pressure increases. EXAMPLE Water being measured; diameter of orifice, 2 inches; diameter of pipe, 4 inches (standard); differential, 1.84 inches of mercury (pressure connections and U gauge above mercury filled with water); pressure connections at 2J/2 and 8 diameters. 2 00 Ratio diam. of orifice to diam. of pipe, X = - = .497. 4.026 C v for ratio .497 = .736. (Page 108). Inasmuch as the gauge and gauge connections are filled with water, each inch of mercury differential is offset by an inch of water so that 1 inch of mercury indicates only 12.6 inches of water pressure differential due to flow. Therefore, the pressure differential is 1.84X12.6 = 23.2 inches of water. See Page 38. 113 ORIFICE METER MEASUREMENT 00 O = = 1.93 feet head of water. 12 = . 736V 2X32.16X1.93 F = 8.20 feet per second. Area of Orifice = .0218 (Page 75). Quantity=.0218X8.20 = .179 cu. ft. per second. Therefore, the quantity per hour =.179X7.48X3600 = 4820 gallons per hour, where one cu. ft. equals 7.48 gallons. EXAMPLE Oil being measured; diameter of orifice, 2 inches; diameter of pipe, 4.026 inches; differential, 1.84 inches of mercury, gauge lines and gauge filled with oil; Baume gravity, 30 degrees; viscosity, 25 seconds Saybolt. (in this case the viscosity of the oil is less than that of water and therefore the coefficient of velocity for the oil is the same as coefficient of velocity for air. Diameter of Orifice 2.000 Ratio X = = = .497 Diameter of Pipe 4.026 C v for .497 ratio = .736 (Page 108) As the specific gravity of this oil is .875 compared with water, each inch of mercury = 13. 6/. 875 = 15.54 inches of oil, but each inch of mercury differential is offset by a pressure equal to one inch of oil and therefore, each inch of mercury differential indicates 15.54 1.00 or 14.54 inches of oil dif- ferential. Therefore, the differential pressure = 1.84X14. 54 = 26.8 inches of oil = 2.23 ft. See Page 38. V = C V V 2gH= .736 V 2X32.16X2.23 = 8.81 feet per sec. Quantity = .0218 X 8.81 feet per second = .192 cubic feet per second = 691 cubic feet per hour = 691/5.615 or 123 barrels per hour, where 5.615 cubic feet equals one barrel. In the case of oil and water the amount measured is de- pendent only on the differential. The pressure does not pro- duce any effect on the volume or the differential. 114 ORIFICE METER MEASUREMENT To simplify all calculations for orifice meter measurement the values of H (the differential in feet head of flowing fluid) , have been expressed in terms of inches of water differential for liquids and in terms of inches of water head and pressure in pounds per square inch absolute for air, gases and vapors. The multipliers used, the area of the orifice and units of measurement are combined in one term, for the conditions of flow at any orifice. This term is known as the Hourly Orifice Coefficient C, which is used in the following simple formulae. It is the volume per hour at a one inch differential (in cases of gases at 1 Ib. per square inch absolute). For gases Q = For liquids Q = Where Q = quantity per hour expressed in weight or volume. C = Hourly Orifice Coefficient. ' This value does not change for any orifice when measuring fluids of the same specific gravity. The coefficient for an orifice of any commercial size for gas, air, steam, water, oil, etc., are contained in the tables in this volume. h = the differential pressure existing between the two pressure connections expressed in inches of water head, this value being recorded graphical- ly on the chart of the recording differential gauge. P = the static pressure expressed in absolute units, being equal to the atmospheric pressure plus the gauge pressure (which is recorded on the chart). The value of the gauge pressure is also recorded on the chart. In measuring liquids the static pressure is ignored as liquids are nearly incompressible. 115 ORIFICE METER MEASUREMENT Extensions of the value of V hP for differential pres- sures from 1 to 100 inches water head and for all static pressure ranges from 29 inches mercuiy vacuum to 500 Ib. gauge pressure are contained in the book, "Pressure Exten- sions," published by this company. For a detailed explanation of the above formulae and their application to the measurement of air, gas, steam and liquids, the reader is referred to the Parts 4, 5, 6, and 7. Fig. 53 DIFFERENTIAL GAUGE, 10 INCH DIFFERENTIAL RANGE 116 ORIFICE METER MEASUREMENT MERCURY FLOAT TYPE DIFFERENTIAL GAUGES As iron weighs approximately .26 Ib. per cubic inch, and mercury weighs approximately .49 Ib. per cubic inch iron will float in mercury. This makes a very desirable com- bination for a differential gauge, as the mercury is a very sensitive liquid and will not freeze above a temperature of 40 deg. fahr. below zero. The mercury float type differential gauge is primarily a U tube made of semi-steel and steel in which mercury is used as a seal. A cast iron or steel float which floats in the mercury is placed in either the high or low pressure column of the U tube and is connected by a lever and shaft (working through a stuffing box) with the pen arm. The pen of the pen arm records on a chart which is rotated by clock work. Some of the gauges are constructed with the one column of the U tube surrounding the other column. Fig. 35 illustrates such a gauge in which the high pressure column surrounds the low pressure column and in which the float rests in the mercury in the low pressure column. Fig. 54 illustrates a type of gauge which resembles the ordinary U tube. In this type also the float rests in the mercury in the lower pressure column. The line pressure upstream from the orifice is admitted to column H and the downstream pressure to column L, so that both columns are under line pressure. The recording parts, clock, etc., which are contained in the case, are under the atmospheric pressure. In Fig. 54 when the pen is in the zero position the float is raised about one-eighth inch above the bottom of the column L. As the pressure in column H increases over the pressure in column L, the mercury lowers in column H and rises in column L, raising the float. The rise and fall of the float is transmitted .by the lever and shaft to the pen arm which indicates on the chart the rise and fall of the mercury 117 ORIFICE METER MEASUREMENT in the column in which the float is placed. The charts used are graduated in inches of water differential to indicate the difference of pressures acting in the columns of the gauge. For each 13.6 inches of water differential the difference in the elevation of mercury in the two columns is one inch. For 27.2 inches of water the difference is 2 inches of mercury, etc., so that for each inch increase of water differential recorded on the chart the increased difference in the mer- cury levels of the two columns is .0735 inch. Therefore, for a 20 inch water differential the difference in mercury levels is 1.47 inches. At the zero position the surfaces of the mer- cury in the two columns are on the same level but due to the difference in areas of the columns, the mercury in the column H will fall more rapidly than it will rise in column L. For instance, if column L is four times the area of column H, for each inch of mercury differential the mercury will fall .8 of an inch in column H while it rises .2 of an inch in column L. This is necessarily so because the volume of mercury displaced in the one column must be equal to the volume of mercury added to the other column. In differential gauges where the chambers or columns are uniform in area through- out the column, each equal increase of differential will cause an equal increase in rise in the column L and consequently, an equal increase in rise of the float. Providing the arc over which the float joint travels is small the pen attached to the differential arm will travel over equal spaces on the chart for equal increases of mercury differential. The pressure which causes the float to rise is equal to the area of the float multiplied by the distance through which the mercury rises for each increase in differential by the weight of mercury per cubic inch, and the force which tends to overcome the friction of the shaft in the stuffing box is equal to this pressure multiplied by the length of the float lever. Therefore, it is evident that the larger the float and the longer the lever the more force there is to overcome the 118 ORIFICE METER MEASUREMENT CHECK VALVE DOWNSTREAM CONNECTION FLOAT LEVER F UPSTREAM CONNECTION CHECK VALVE PRESSURE SPRING COLUMN H DIFFERENTIAL PRESSURE PEN ARM Fig. 54 SECTIONAL VIEW OF A 100 INCH DIFFERENTIAL AND STATIC PRESSURE GAUGE THE 50 INCH GAUGE IS SIMILAR IN DESIGN 119 ORIFICE METER MEASUREMENT friction of the stuffing box, hence greater sensitiveness. There must be friction in stuffing boxes as it is the friction only which prevents leakage. The friction in the stuffing box may be reduced by using a smaller pin through the stuffing box but there is a limit to the size of this pin due to the bending effect which may be caused by the weight of the pen arm. Due to the fact that the travel of the pen is proportional to the rise of the float and the length of the float lever, if when checking a gauge against a water column, at zero check the pen is on the zero line and at 20 inches on the water column the pen rests on the 19 inch line, and when the water column indicates 40 inches, the pen is slow and rests at 38 inches, it is evident that a reduction of the effective length of the float lever will cause the pen arm to move more rapidly. If the distance between the float joint and the shaft is de- creased by one twentieth (in this case)" the pen will record correctly. The mercury will always register the proper dif- ferential, but the levers, etc., may not be in proper adjust- ment to indicate correctly in inches of water. All mercury float type gauges which are exposed to the elements, are subject to temperature variations due to the fact that the mercury expands when the temperature in- creases, and contracts when the temperature decreases. This statement also applies to steel. The cubical expansion of mercury for 1 deg. fahr., is .000099, and the cubical expansion of steel is .000017, so that the difference between cubical expansion of mercury and of steel causes a rise of the mercury for a 50 degree increase in temperature which will produce a movement on the pen arm in a 50 inch gauge, equivalent to % of 1 inch of water pressure and vice versa. If a gauge of this type is set on zero in the cool part of the day and the temperature of the mercury rises 50 degrees during the day, when the gauge is again checked for zero at the time when the temperature is the greatest the pen arm 120 ORIFICE METER MEASUREMENT will be about Y& of an inch above the zero line. From the above it may be thought that this error could be eliminated by using less mercury, but in all types of gauges which use lesser quantities of mercury, the area of the chambers is also decreased, or the ratio of the rise of the float to the movement of the pen arm, is decreased, so that the net effect on all gauges is approximately the same. The error due to a 50 degree change of temperature will make a difference equi- valent to one-third of one per cent of the maximum range of the gauge. Therefore, to eliminate this discrepancy the gauge should be sheltered and protected from extreme tem- perature changes. ACCURACY OF ORIFICE METER The Orifice Meter and its Differential Gauge are like the Large Capacity Meter. When given proper attention they will give results as accurate as any measuring instrument known. A great many users have the impression that the orifice is the main part of the meter and therefore cannot "get out of order." While it is true that the orifice itself will not easily change its diameter or shape or "get out of order," the Differential Gauge is a delicate recording instrument and must be checked periodically and kept in good condi- tion, free from condensation. In addition to this it is very important that the coefficient be based on the true conditions of the gas or liquid measured. The weighing or measuring device that will not become inaccurate at some time or other has not been invented. Even the measuring rule will shrink as it grows older. Another point that is seldom considered by users of Orifice Meters, is that when a differential gauge is out of adjustment and the pen arm reads too low or too high, the error is not expressed in percentage figures. 121 ORIFICE METER MEASUREMENT 122 ORIFICE METER MEASUREMENT For instance, if the differential pen arm records two inches in error, it is spoken of as merely two inches too high or too. low, and the error is seldom expressed in per cent. The percentage of error due to a differential pen arm recording too high or too low is dependent on whether the differential pressure is ranging around a low or a high value. If the differential pressure should average 10 inches of water pressure and the pen arm should be found to be recording two inches too high or too low, the error would be 12 per cent fast or 9 per cent slow. While if the differential pressure should range between 40 and 44 inches of water pressure with the same error of 2 inches in the differential pen arm the error would be about 2.5 per cent. The error due to an erratic static pressure pen arm or a static pen arm that records too low or too high can likewise be expressed in percentage figures. The percentage fast or slow varies according to the static pressure of the gas mea- sured. It is greatest for low pressure and smallest for high pressure. If the static pressure pen arm reads 2 Ib. high at atmospheric pressure, the percentage fast would be 6.7. If the static pressure ranges around 400 Ib. and the static pen arm records 2 Ib. high, the error would be 0.24 per cent fast. From the foregoing the reader will note there is greater necessity of having both the static and differential pen arms recording more accurately at low pressures than at high pressures. In addition to any error from an erratic static or dif- ferential pen arm, the error constantly exists if the coeffi- cient is not revised for the true conditions, for instance, specific gravity when measuring gas. If the orifice coefficient is based on a specific gravity of .6 and the true specific gravity of the gas measured is .65, the result would be 4 per cent too high, or if the coefficient was based on a specific 123 ORIFICE METER MEASUREMENT gravity of .65, and the true specific gravity of the gas was .6, the result would be 4 per cent too low. To give an example where all three errors occur : Assume that the differential pen arm was marking two inches high and the static pressure pen arm was marking two pounds high, also that the true gravity of the gas was .70 instead of .65 upon which the coefficient was calculated. Using an hourly coefficient of 1000, differential 12 inches of water, and static pressure 12 lb., then the formula would read: 100 V 12 (14.4+ 12) = 17,799 cu. ft. With the differential pen arm marking two inches too high, deduct 8 per cent With the static pen arm marking two lb. too high, deduct 4 per cent To correct for true gravity of gas from .65 to .70, deduct 4 per cent Total per cent fast 16 per cent. 17,799X84% = 15,051 cu. ft. To prove error, change formula to read with correct pressures : 100 V 10 (14.4+ 10) = 15,621 cu. ft. To correct this result for change in specific gravity from .65 to .70: 15,621 X .9636 - 15,052 cu. ft. In giving the foregoing or following facts and figures it is not the intention of the author to discredit the accuracy of the Orifice Meter as a measuring instrument, but to put forth the true facts in such a light that the orifice meter users will fully understand what the different errors mean in per- centage figures, and to create a better understanding of this type of meter, that greater accuracy may be obtained. 124 ORIFICE METER MEASUREMENT 125 ORIFICE METER MEASUREMENT Table 22 DIFFERENTIAL GAUGE CAPACITIES Capacity ranges of Differential Gauges. Same Orifice and Pipe. Hourly Orifice Coefficient 100. Maximum Closest Minimum Ratio of Reading Maximum Reasonable Chart Minimum Maximum Chart Capacity Reading Reading* Capacity to Mini- Inches Inches Inches mum Flow 100 1000 0.4 8.0 283 3.5 50 707 0.2 4.0 200 3.5 25 500 0.1 2.0 141 3.5 20 447 0.08 1.6 127 3.5 10 316 0.04 0.8 89 3.5 2.5 158 0.01 0.2 45 3.5 *Minimum chart reading corresponds to a 2J^ per cent devia- tion in results for the closest reasonable reading. The above Table is self explanatory and is given to illustrate the capacity relations of various ranges of gauges, also the fact that the ratio of maximum to minimum flow is the same regardless of the maximum differential range of the chart, when we use the same standard for determining the minimum chart reading which ultimately is the limit of ordinary vision. The maximum capacity for a 100 inch gauge is twice as great as for a 25 inch gauge, but it is likewise true that the minimum capacity of the 100 inch gauge is also twice as great. The relative capacities are based on an Hourly Orifice Coefficient of 100 for water. The relations shown are the same for any liquid, or a gas at a definite pressure. DIFFERENTIAL RANGE There are many who advocate the 50 inch differential pressure range, and many who prefer the 100 inch range. It is the intention of the author to give the advantages and disadvantages of each pressure range in the following para- graphs. 126 ORIFICE METER MEASUREMENT The first differential gauge placed on the market carried a metallic spring instead of a mercury pot, and a 100 inch differential pressure range. It was generally conceded that the 100 inch pressure range for that type of differential gauge was the best. Manufacturers advised that this type of gauge gave best service working at a range from 40 inches to 60 inches. The range from 60 inches to 100 was only used in case of an emergency, or when there was an extreme rise in the differential pressure, in which case the pressure range above 60 inches acted as a factor of safety to the spring. The mercury type of differential gauge superseded the spring type, and in itself acts as a safety valve to take care of any extreme rise of differential pressure. To illustrate this : Take a 100 inch differential spring type gauge should the differential pressure increase to 75 inches, the spring would not be affected. Of course, this differential pressure would mean a drop in the pressure in the gas or liquid passing through the meter of about 2% Ib. for small sizes of orifices. Should this same rise in differential pressure occur with a spring type gauge with a pressure range of 50 inches, the spring would break, putting the gauge out of commission. With the 50 inch range of the mercury type differential gauge in which the mercury acts as a seal or safety valve, the gauge would not be injured by the rise in pressure above 50 inches, as the pen would be checked at fifty inches. In measuring a certain volume of gas where a 100 inch differential pressure gauge is used, 71 per cent of the volume is measured by the first fifty inches and 29 per cent by the second 50 inches or that part of the range between 50 inches and 100 inches. However, the maximum capacity of a 100 inch gauge is 41 per cent greater than a fifty inch gauge. See article on Capacities, Page 126. When measuring fluids in high pressure lines where the loss of pressure is not an objectionable factor, and where large 127 ORIFICE METER MEASUREMENT H -. tj ORIFICE METER MEASUREMENT capacity is desired a 50 or 100 inch gauge should be used. For casinghead gas and all vapors and liquids when the line pressure is less than 50 Ib. per sq. in., gauges having a 10 or 20 inch maximum differential range should be used. For gas and air lines where the pressure is nearly atmospheric, a 2 J/2 inch gauge will give excellent results with an extremely low friction loss. SPECIAL TYPES OF DIFFERENTIAL GAUGES Differential Gauge, 2^ inch Range This particular type of gauge, which uses oil instead of mercury as a seal, is especially adaptable for the measurement of gases under pressures which do not vary appreciably from the atmos- pheric pressure. As noted on Page 126 the range of this gauge from maximum to minimum is the same as any dif- ferential gauge. The great advantage in this gauge being that the pressure loss occasioned at the orifice to produce a reasonable reading is very slight, not amounting to more than one inch of water pressure on the average. Combination Gauge Gauges have been placed on the market which have a to 25 inch differential range or to 100 inch differential range using the same gauge. This gauge is especially adaptable to locations where the flow varies for certain periods, and where it is undesirable or inadvisable to change the orifice in order to obtain a reason- able reading. By using this type of gauge, the operator can increase the range of the same orifice for reasonable readings from 3J/2 to 1, to 7 to 1, without any change of orifice whatever. For instance, if for a period of a month the hourly flow varies from 100,000 to 350,000 feet per hour and during the subsequent month the flow decreases and varies between 50,000 and 175,000 per hour, it is possible to make the entire change in the gauge without any change of the orifice, thus eliminating any breaking of the line. 129 ORIFICE METER MEASUREMENT This change is made by simply interchanging the bushings or plugs which are used in the high pressure mercury cham- ber and thus decreasing or increasing the area of the pot. The working parts are not disturbed at all. A 25 inch chart is used when the 25 inch bushing is in place, and the 100 inch chart is used when the 100 inch bushing is in place. This type can be used to great advantage in measuring steam, water and oil where by-passes are undesirable. Page 325. Indicating Gauges Gauges have been designed which have doors made of one sheet of metal in which a diagram is placed under glass in the section of the door under which the differential pen arm moves. This diagram is slotted and contains a scale between the slots on which is indicated the rate of flow per hour corresponding to various pressures. The operator by simply noting the static pressure at which the gauge is working and by following the arc on the diagram can determine the flow per hour on the scale reading over the differential pen arm. These gauges indicate the rate of flow within 3 per cent. They are especially adaptable for those locations where it is desirable to change the rate of flow by increasing or decreasing the pressure and differential. Due to the various State Regulations, etc., it is necessary to draw at a uniform rate from the wells and quite frequently, due to the sudden increase in demand, it is necessary to in- crease the rate of flow. The office man simply tells the field man to increase the flow from 100,000 to 200,000 pro- viding the field man has been passing 100,000 feet per hour and the field man is able to make this change without any calculations on his part whatever, simply by increasing the pressure and differential and noting the scale reading op- posite the differential pen arm. The doors of the gauge are made standard so that they can be used to replace doors on other gauges now in use. These indicating gauges are especially desirable for measuring steam or oil. 130 ORIFICE METER MEASUREMENT Fig. 58 DIFFERENTIAL GAUGE WHICH INDICATES RATE OF FLOW PER HOUR. IN MEASURING GAS THE RESULT IS READ IN CUBIC FEET PER HOUR. THIS DOES AWAY WITH THE NEED OF PRESSURE EXTENSIONS TO DETERMINE THE RATE OF FLOW. SEE PAGE 299. Patent applied for. 131 ORIFICE METER MEASUREMENT Recording Differential and Static Pressure and Temper- ture Gauge These Differential and Static Pressure Gauges are equipped with recording thermometer so that the flowing temperature of the gas is recorded on the same chart as the differential and static pressure. Gauges of this character can be used to advantage on large gas mains where it is de- sired to make a correction for the amount of flowing gas according to temperature of the gas. The temperature is recorded inside of the zero differential circle of the chart. The benefit of having the three records on one chart is ob- vious. See Page 234. DEVIATION IN FLOW DUE TO HIGH RATIO OF DIFFERENTIAL TO PRESSURE In all of the calculations relative to flow of fluids through orifices the general formulae and expressions of flow have been simplified and are based on the assumption that the difference between the upstream pressure and the downstream pressure is small when compared with either the upstream or the down- stream pressure, or that the ratio of the differential to the pressure is small. In measuring fluids which are nearly incompressible, such as water or oil through an orifice meter, there is practi- cally no change in the density as the fluid passes the orifice. The quantity is correctly represented by the formula Q = CV h when the velocity is less than the critical velocity. When measuring compressible fluids ssach as air, natural gas, artifical gas, hydrogen, etc., the density of the fluid is changed. The quantity flowing is based on the velocity which is obtained by calculating the formula V = C v ^2gH, where H is the differential expressed in feet head of flowing fluid. The value of H varies and depends on the line pressure. Theoretically it is assumed that the line pressures at both connections are the same but this is not true due to the dif- ferential created by the orifice. As the ratio of the dif- ferential to the line pressure increases, the greater will be 132 ORIFICE METER MEASUREMENT the difference in values of the differential in feet head of flowing fluid when expressed in terms of the upstream and downstream pressure. Velocity at Ori- fice in feet per sec. Deviation of cal- culated result, from true re- sult, in pei- cent. Velocity at Ori- fice in feet per sec. Deviation of cal- culated result, from true re- sult, in per cent 900 800 700 600 17.0 14.8 12.6 10.4 500 400 300 8.2 6.0 3.8 Recently a series of 30 tests was conducted in which the ratios of differential to the downstream pressure varied from 10 per cent to 100 per cent. A holder was used as a standard of measurement. Deviations in percentage of the calculated volumes, using the published Coefficients of the orifices, from the actual volume were plotted for two types of connections, one where pressures were obtained at pipe connections (static pressure at the downstream connection) and the other where the pressures were obtained at the flanges (static pressure at the downstream connection). These deviations were plotted against the actual velocity of the air through the orifice and indicated that the percentage deviation for either of the types of connections was the same for the same rate of flow in feet per second, being plus for the upstream static pressure connection and minus for the downstream static connection. The number of tests are too meager to indicate or develop a formula or curve for a series of mutlipliers to be used when high ratios of differential to pressure exist. On account of the varying value of the coefficient of velocity, it is im- possible to give definite factors from the data obtained for various ratios of diameter of orifice to diameter of pipe. All of the published Coefficients were based upon experi- mental data obtained by using orifices in which the ratio of 133 ORIFICE METER MEASUREMENT -F/pG Tops or connec6/ons- r~/ange Tops or Connect; Sons / - Or/ free H* g*JL -*/>// m. of P/p& -x?^ ttys i pa/st& i/ne rr& ' Fig. 59 SKETCH SHOWING STREAM FLOW THROUGH AN ORIFICE AND THE RELATIVE STATIC PRESSURES AT VARIOUS POINTS LONGITUDINAL SCALES ARE THE SAME diameters upstream and 8 diameters downstream from the orifice, these connections are called Full Flow Connections and quite frequently are known as Pipe Taps. When the taps for the pressure connections are made close to the orifice, through the flanges, the taps are called Flange Taps. See Fig. 59. In the 2J/2 and 8 diameter or Pipe Tap installation, the connections are made at points where the stream line flow occupies the full section of the pipe, hence the descriptive term Full Flow Connections. These points were chosen by the first experimenters as being the points at which the differential would be approximately the least and the most consistent that could be obtained by any combination of points. In other words, the line pressure at a point 2J/2 diameters upstream is the least pressure that exists upstream from the orifice, and the pressure at a point 8 diameters downstream is the greatest uniform pressure which exists below the orifice. The point of maximum downstream pres- sure is about 6 diameters downstream from the orifice. Where the pressures are obtained at the flanges, the upstream pressure is slightly greater than the minimum upstream pressure, and the pressure at the downstream con- 135 ORIFICE METER MEASUREMENT nection is slightly greater than the least downstream pres- sure (in the vicinity of the orifice). The least pressure (near the orifice) exists about ^ of the pipe diameter down- stream from the orifice. From the above facts it follows that the differential pressure between connections at the flanges is always greater for the same velocity through the same orifice (See Fig. 59) than that obtained at the Pipe Taps, (one connection 2J/2 diameters upstream and the other 8 diameters downstream) . In other words, the differential obtained between taps at the flanges is an exaggerated differential. When taps are made in the flanges for connections the openings must be located with precision as a small variation in the distance from the flanges produces an appreciable change in the differential due to the fact that the pressure varies at points within J4 of a diameter of the orifice. At the points for Full Flow Connections a variation of an inch in the location does not produce a readable effect, for the reason that the pressures at these points and at points within a diameter in either direction are steady and do not vary appreciably. Friction Loss The following Table gives the percentages of friction loss to total differential for Full Flow and Flange Connections for various ratios of orifice to size of pipe. Table 23 Percentage of Friction Loss to Differential Ratio X Full Flow Con- Flange Connec- v Diameter of Orifice nections Per Cent Loss tions Per Cent Loss Diameter of Pipe .15 100 96 .30 100 89 .45 100 75 .60 92 57 .75 80 40 136 ORIFICE METER MEASUREMENT 137 ORIFICE METER MEASUREMENT The friction losfe at a 2% inch orifice in a 6 inch line for a 50 inch differential reading is 100 per cent or 50 inches with Full Flow Connections, and 38 inches when the same dif- ferential is obtained when using the same orifice with Flange Connections. If a 4J^ inch orifice is used in a 6 inch pipe the friction loss at 50 inch differential reading is 40 inches, and 20 inches for the Full Flow Connections and Flange Con- nections respectively. This relation may be expressed as follows. With Full Flow Connections the differential is 1J4 times the friction loss and with Flange Connections the differential is 2^ times the friction loss at an orifice which is % of the diameter of the pipe. It is noted that the friction loss percentage decreases as the size of the orifice increases. At a first glance it would seem that the Flange Con- nections are preferable, but it is a self evident fact that with a definite rate of flow through an orifice the friction loss will be the same as long as the same orifice is used in the same pipe. The loss does not depend on whether the pressures are obtained at a mile away on each side of the orifice or within H inch. Table 23 does not tell the whole story for it does not take into consideration the larger value of the coeffi- cient for the Full Flow Connections when using the same size of orifice in the same pipe. See Fig. 60. In Table 24 it is shown that for the same size of orifice the Hourly Orifice Coefficient for Pipe Tap connections is always greater than the Hourly Orifice Coefficient for Flange Tap connections and that for the larger sizes of ori- fices the Pipe Tap coefficient becomes considerably greater than the Flange Tap coefficient. In order to indicate the same flow the differential reading on the chart of the gauge attached to the flange taps reaches its maximum limit (20 inches) , when the pen of the other gauge is registering at one-half of its maximum range, (10 inches). The friction loss in each case is the same for the same flow. 138 ORIFICE METER MEASUREMENT Table 24 Comparison between two 20 inch Differential Gauges, measuring the same flow through the same orifice (one with Pipe Tap connections and the other with pressure connections at the flanges) when the gauge connected to the Pipe Taps is indicating a 10 inch reading. Gauge with Connections Gauge with Connections Dia- at Pipe Taps at Flange Taps meter of Ori- fice Quan- tity Coeffi- Chart Read- Fric- tion Loss Coeffi- Chart Read- Fric- tion Loss Inches cient ing Inches Inches cient ing Inches Inches of Water of Water of Water of Water *A 836 83.6 10 10 81.8 10.5 10 IK 3506 350.6 10 10 327.4 11.5 10 1% 7382 738.2 10 10 642.5 13.2 10 2 1 A 18562 1856.2 10 9 1429.8 16.8 9 3 32962 3296.2 10 8 2322.7 20.0 8 Size of Pipe 4.026 inches. Pressure 10 Ib. absolute. Air being measured. Table 25 Comparing two 50 inch gauges, one with Full Flow Connections and the other with Flange Connections each indicating a differ- ential of 25 inches, (except as noted). Size of Pipe 4 inches. Air being Measured. Pressure 16 Ib. Absolute. Full Flow Connections Flange Connections Dia- meter of Orifice Inches Hourly Orifice Coeffi- cient Quan- tity cu. ft. per hour Fric- tion Loss Inches Water Dia- meter of Orifice Inches Hourly Orifice Coeffi- cient Quan- tity cu. ft. per hour Fric- tion Loss Inches Water H 83.6 1672 25 % 81.8 1636 24 IK 350.6 7012 25 IK 327.4 6548 22 IK 738.2 14764 25 IK 642.5 12850 19 2}/2 1856.2 37124 23 V/2 1429.8 28596 14 2^ 2481.9 49638 21 3 2322.7 46454 10 3 3296.2 65924 20 3 2322.7 65690* 20 *At 50 inches differential 139 ORIFICE METER MEASUREMENT In Table 25 it is shown that for various quantities of gas passing the same orifice at the same differential, the friction loss is less for Flange Connections but the quan- tity is also less, also that in order to measure the same maxi- mum quantity that the gauge with Full Flow Connections measures at a 25 inch reading, the gauge with Flange Con- nections must indicate at the limit of the chart in which case the pressure loss is the same. The following table shows very clearly that a gauge of a certain maximum range with Full Flow Connections will measure the same or slightly greater quantities at the same relative chart reading with a less friction loss than a gauge of double its maximum range with Flange Connections. Table 26 Comparison between a 50 inch gauge with 2J/2 and 8 diameter connections and a 100 inch gauge with Flange Connections, each gauge indicating a differential equal to }/ of its maximum differential range. Size of Pipe 4 inches. Air being measured. Pressure 50 Ib. absolute. 50 in. Gauge, Full Flow Connections 100 in. Gauge, Flange Con- nections Dia- meter of Orifice Inches Hourly Orifice Coeffi- cient Quan- tity cu. ft. per Hour Fric- tion Loss Inches Water Dia- meter of Orifice Inches Hourly Orifice Coeffi- cient Quan- tity cu. ft. per Hour Fric- tion Loss Inches Water H 121.1 4284 25 H 81.84 4092 48 V4 519.9 18390 25 1M 327.4 16370 44 2 1019.4 36070 25 m 642.5 32130 38 2% 2146.8 76070 22 &A 1429.8 71500 27 3 3296.2 116620 20 3 2322.7 116100 20 It is noted that a 50 inch gauge at the maximum size of orifice with Full Flow Connections has approximately the same capacity as a 100 inch gauge with Flange Connections. These ratios and percentages are true for the same relative capacities of gauges. 140 ORIFICE METER MEASUREMENT Considerable has been said in regard to the merits of both types of connections relative to friction loss, capacities, etc., but the gist of the facts is as follows. The Flange Connections are more compact; the gauges indicate a higher differential for the same flow through the same orifice ; the taps must be located with greater precision. Full Flow (Pipe Tap) Con- nections are located at points where the pressures are uni- form and steady; the range of capacity is 41 per cent greater from minimum to maximum size of orifice for the same pipe ; the gauges indicate a lower differential, requiring a smaller maximum range of gauge for the same flow. Friction loss depends solely on the rates of flow, size of orifice and size of pipe. The larger the orifice the less the friction loss which in turn means a lower differential and a gauge of low maximum range regardless of the type of con- nections. PRESSURE LOSS Whenever an orifice is placed in a line a loss of pressure is created. This loss varies from 40 to 100 per cent of the differential reading (See Page 136) on the chart. For in- stance, if the differential reading is 54 inches the loss in pres- sure is not less than 21 inches of water or 0.8 Ib. and may amount to 54 inches of water or 2 Ib. through the orifice de- pending on the location of the pressure connections and the size of orifice. As the size of the orifice increases the pro- portion of pressure loss due to friction compared to differential reading becomes less. For smaller sizes of orifices the lost head is equal or nearly equal to the differential pressure. On a vacuum line this loss creates a less vacuum at the well if the meter is placed between the pump and the well. Each 13.6 inches of water pressure amounts to 1 inch of mercury vacuum. For example, if a vacuum pump pulling 26 inches of vacuum is placed on a line and the normal pressure loss through the line without an orifice is 4 inches of mercury head, the vacuum at the well would be 22 inches. If a 141 ORIFICE METER MEASUREMENT small orifice is placed in this line and the differential gauge reading is 54 inches of water (approximately 4 inches of mer- cury head) then the vacuum existing at the well is only 18 inches. In this case it will be noted that the orifice creates as much friction loss as the pipe line itself. To overcome this difficulty differential gauges having a maximum reading of 10 and 20 inches have been placed on the market. By using meters of these lower ranges the size of the orifice is increased, thereby decreasing the total dif- ferential pressure required to obtain an accurate reading. The proportionate friction loss as compared with the dif- ferential reading is likewise decreased. The use of orifice meters having a differential range of from 60 to 100 inches on vacuum lines should be discouraged on account of the friction losses above stated. Any dif- ferential gauge having a range from to 10 inches or greater, will have a capacity sufficient to measure the flow through any vacuum line. The maximum capacity of a 10 inch differential gauge is 32 per cent of the maximum capacity of a 100 inch gauge and 71 per cent of the maximum capacity of the 20 inch gauge. However, the friction loss in measuring the same quantity of gas at the same relative reading on the 10 inch differential gauge chart is less than 10 per cent of the friction loss occasioned by using a 100 inch gauge and less than 50 per cent of that for a 20 inch gauge. For instance, in the previous example with a 10 inch gauge at the same rela- tive chart reading of 5.6 inches the friction loss would be less than 5.6 inches of water pressure or 0.4 inches of mercury head which would leave a vacuum of 21.6 inches at the well with 26 inches at the pump, a line loss of 4 inches mercury head and a meter loss of .4 inches of mercury. Although it is possible to obtain low readings from differential gauges having the higher ranges the same percentage of accuracy in reading cannot be obtained, as when using gauges of lower maximum ranges. For instance, the closest reasonable 142 ORIFICE METER MEASUREMENT reading which could be obtained on a 100 inch chart is about ^/2 of an inch. The error for a 2 inch differential reading will amount to 12 per cent, whereas, on a 10 inch chart it is easily possible to obtain readings within .05 inch, which would amount to 1J4 per cent deviation for a 2 inch differential reading. (See Page 126). PULSATING FLOW A great many people believe that when they have a pul- sating volume of gas or liquid to be measured, it is only necessary to install "deadeners" or pinch valves on gauge lines to the differential gauge in order to obtain accuracy. This is erroneous. Simply because one kills the pulsation in the lines leading to the high and low pressure side of the differential gauge does not mean that they have stopped the pulsation of the fluid passing through the orifice. It is not practicable to measure pulsating flow by either one orifice meter or a displacement meter. It is as unreasonable as to attempt to weigh a person jumping around on a penny-in- the-slot weighing machine. The problem which has proven most puzzling has been the measurement of a pulsating flow. This is particularly true where the pulsations are rhythmic, as in the vicinity of compressor stations with reciprocating compressor pistons. The following statement illustrates the varying results ob- tained in measuring gas where the pulsations were produced by compressors. An orifice meter early installed at such a location failed to check with the station or with meters some 17 miles away on the same line. In endeavoring to locate the difficulty, a series of recording gauges was installed, both with and without devices for "deadening" the pulsations in the lines leading to the gauges. Finally a spring recording gauge, a mercury float gauge of the type originally installed, a differential recording gauge, and a water U tube, were con- nected in parallel. These gauges were all calibrated in 143 ORIFICE METER MEASUREMENT unison, and agreed very well under conditions of steady flow. When the compressor station was started, the gauges took widely varying positions; some dropped down to half their former reading, despite the increased flow, one took a nega- tive reading as though the flow were reversed and the water column took a wholly indeterminate condition of churned foam ; some of the gauges moved about in an erratic way and others gave steady indications, but wholly unrelated to the quantity of gas. A proportional meter installed in tandem at this point gave, over a period of months, a record erratic and irreconcilable as compared with pump station displace- ment, line flow formula, or meters 17 miles away operating on the same gas with steady flow. Similar disturbances in the accuracy of the record are occasioned by irregular pulsations occasioned by the action of fluid in the line. Disturbances are particularly serious when occasioned by irregular or imperfect action of auto- matic pressure regulators in the vicinity of the meter. One attempt was made where a device was installed ahead of a compressor station with the idea of dividing the gas into about 20 different streams and making each stream traverse a path of different length so that the wave motion from different parts of the cycle would be made to interfere at the point where the gas was again brought to a common line. This was almost successful, and it is believed that by a little further calculation and change of arrangement to secure more perfect interference a measurement at this point may be secured. Pulsations due to fluid and imperfect regulators are obviously questions of simple correction, by separators, drips and mechanical repairs. To obtain accuracy where the gas pulsates badly, one should eliminate the pulsation or move the orifice meter to an- other location. To eliminate pulsation it is necessary to install drip tanks or more pipe area on the inlet side of the meter. 144 ORIFICE METER MEASUREMENT Compressors are the greatest producers of pulsation. Regulators, and gates near the meter, and water or oil in a gas line will also create pulsation in the line. Where pulsation is caused by regulators or fittings it is not a difficult matter to move the regulators or fittings far enough back of the meter so as not to cause counter currents, eddies, or pulsations. Of course, a very slight pulsation may not have any ma- terial effect on the accuracy of the orifice meter, but it is best to have none. Pulsation and Vibration In order to cover this subject thoroughly a distinction must be made between a vibrating differential pen arm and the pulsating flow which occurs through the orifice. The differential pen arm will vibrate due to several causes such as; intermittent flow from a well, varying speed of a. compressor or pump, non-uniform consumption by a drilling boiler, etc. In these cases the change in the rate of flow is slow enough to permit the differential pen arm to entirely or partially record the changes. The pulsation which is produced by the rapidly changing rate of flow due to a compressor or pump, is usually so rapid that the differential pen arm indicates a uniform smooth record which may be greatly in error depending entirely upon the character of the wave motion. Vibration of Differential Pen Arm In endeavoring to de- crease the vibration of the differential pen arm, the use of washers or the method of partially closing valves on the gauge lines, is not satisfactory as any very small leaks between the valves and the gauge will produce an erroneous reading. Washers may become partially stopped up and actually pre- vent the full pressure at the connection from being exerted on the mercury. Where it is impossible to place large chambers or reservoirs in the main line to eliminate the vibration, the vibration can be reduced most satisfactorily when the dif- 145 ORIFICE METER MEASUREMENT f erential gauges are equipped with small bushings which re- tard the flow of mercury from the high pressure portion of the gauge to the low pressure portion of the gauge, or vice versa. By using these bushings it is possible to automatically aver- age the peaks and hollows of the differential reading, in cases of wells which flow by heads or where a well is supplying fuel to a drilling boiler or any machine at which the consumption of fuel is intermittent, and thereby reduce the time required in the office to estimate the average reading. Bushings in- stalled in the mercury columns do not increase the accuracy of the gauge and do not decrease it except where the move- ment of the differential pen arm is greatly retarded requiring more than three minutes to cover the range of the chart. The results obtained from charts where the differential record is averaged in this way will be the same as would be obtained by averaging each 15 minute period by in- spection. Bven though the vibration is eliminated, pulsation may exist and the layout should be tested as prescribed in the following article if there is a possibility of error due to rhythmic pulsation through the orifice. It is almost a certainty that the differential reading is erroneous if the static pen arm vibrates rapidly. Pulsation As an example of the excessive effect the pul- sation due to very rapid uniformly changing rates of flow may have upon results, we show in Fig. 62, layout of the piping in which an orifice meter was installed for measurement of steam. Fig. 63 is a chart obtained while conducting some tests for measurement of steam. It will be noticed in Fig. 62 that the steam header contained two connections to machines using steam, one an air compressor and the other a generator. Some of the steam after passing by these connections was measured by an orifice meter A and subsequently weighed as condensate. The flow of steam through the orifice meter A was regulated by a valve C on the line just prior to conden- 146 ORIFICE METER MEASUREMENT sation of the steam. The clock on the differential gauge was altered so that it made a revolution in approximately 96 minutes, therefore, the chart Fig. 63 moved about 15 times as fast as an ordinary 24 hour chart. Whenever the valve C was opened for a certain number of turns and left in that position, it was noticed in all instances that the rate of flow was uniform. On the chart shown in Fig. 63, valve C was partially opened during a period when both the generator and compressor were shut down, and if they had remained so the reading would have continued uniform corresponding to a differential of 16 inches. Bight minutes after valve C was opened the generator was started and the differential increased from 16 inches to 30 inches without any change in the valve C, consequently without any increase whatever in the amount of steam passing through the orifice. After the compressor was started the differential reading again increased without any increase in the amount of steam passing through the orifice. Inasmuch as the in- crease of differential was not due to an increased flow of steam, the effect was due to the pulsation occasioned by the opening and closing of the slide valves of the generator and compressor, both of them being reciprocating units. It is noted that prior to the test when the machines were not operating that the differential arm remained at zero when there was no steam passing through the orifice, and that after valve C was closed, when there was no steam passing through the orifice, that a differential pressure of approxi- mately 9 inches of water was recorded, due to pulsation only. This differential continued as long as the generator and compressor operated at a uniform speed. The static pen arm in previous tests vibrated over a range of 10 to 15 Ib. with a frequency of the opening and closing of the valves of the reciprocating units when they were operating. To lessen this vibration a dash pot was attached to a static pen arm producing the smooth lines as 147 ORIFICE METER MEASUREMENT shown. The effect of partially closing the valves on the gauge lines also produced a smooth pressure reading but gave erratic differential readings. In all cases when the gauge line valves were fully opened the differential reading was very uniform without any appreciable vibration. The weight of steam passing the orifice checked with a differential reading of 16 inches for the total period of the test, so that the flow corresponded to the reading obtained before the pulsation occurred. The differential due to pulsation caused by the two machines, was 9 inches ; and the differential due to pulsation and flow was 49 inches. As- suming the pressure as 85.6 lb., atmospheric pressure 14.4 and Hourly Orifice Coefficient as 10, the rate of flow due to the differential of 16 inches was 400 lb. per hour. (10V100X16 = 400). The flow corresponding to a 9 inch differential would be 300 lb. per hour (10V 100X9 = 300). For a 49 inch differential the corresponding rate of flow would be 700 lb. per hour. Therefore, the effects due to a pulsation reading of 9 inches increased the flow reading from 16 inches to a combined reading of 49 inches, not simply an addition, but a total reading which was equivalent to the reading which would be obtained by the sum of combined theoretical flows which would have existed for the two independent readings, flow and pulsation (400+300 = 700). With this layout the effect of the pulsation produced a reading equal to the square of the sum of the square root of the flow dif- ferential plus the square root of the pulsation differential. [49= (Vl6+V) 2 =(4+3) 2 ]. A joint of pipe MN was then connected with the main ahead of the orifice. This pipe was closed at the end and an orifice B of the same size as the orifice in the main was in- serted in the line at the same distance from the junction of the two pipes as orifice A. The differential produced by the pulsation at orifice B was the same as at the orifice A without any flow through the orifices on either line. Furthermore, 148 ORIFICE METER MEASUREMENT Steam Header Fig. ORIFICE METER MEASUREMENT the flow through the orifice A was equal to the difference of the flows, as would be calculated from the two charts, the steam flowing through the orifice A producing a reading due to flow plus pulsation, and the orifice C on the dead line producing a reading due to pulsation only. In the layout above described the differential produced by the pulsation only was the same for the same ratio of orifice to size of pipe, i. e., a one-half inch orifice in a two inch pipe produced the same pulsation differential as a one inch orifice in a four inch pipe. The above remarks are the summarized results of more than sixty tests in which the sizes of pipes, orifices and rates of flow were varied in which the length of straight pipe on each side of the orifice was 16 diameters or greater. The effect of shorter lengths were not determined. Gauges may be checked to determine if the pulsation has any serious effect on the registration by closing the down- stream main valve in a layout similar to Fig. 93, permitting the gas to pass through the by-pass and noting whether the differential chart shows a reading when there is no flow through the orifice. If there is a reading and the valve is in good condition it indicates the flow calculated from the dif- ferential reading is in error. If the differential corresponding to a certain flow is 9 inches and the differential caused by pulsation is }/ inch the differential created by the combined effect may be 12.25 inches (V~9~ + V^25) 2 or 6.25 inches (V~9 V.~25) since the effect of the pulsation may decrease the reading as well as increase it, depending on the layout. The use of two meters offers a solution for those locations where it is impossible to install reservoirs or to locate the meters so that the effect of the pulsation can be eliminated; one of the gauges being installed on the main, recording the differential produced by the flow and pulsation, and the other 150 ORIFICE METER MEASUREMENT meter on a dead line registering the imaginary flow due to pulsation. The difference between the results calculated from these charts being the true flow. From the above it is seen that bushings will not produce an accurate indication of the flow even though the recorded differential line is a smooth line, when the static pressure varies uniformly and rapidly for the reason that sufficient time may not elapse between the periods of increased pressure or decreased pressure for the differential pen arm to assume a reading corresponding to the average flow. There is only one way to take care of a situation of this kind with one orifice and that is to place a deadener or reservoir in a main gas line large enough to absorb the shocks and cause a steady flow from the deadener or reservoir. There is no set rule to follow that the writer knows of in regard to when and when not to install a meter where the flow is pulsating. It might be said that in any installation where the static pressure pen arm does not vibrate that the resultant reading obtained may be correct. It is certain that if the static pen arm does vibrate the differential read- ing will be in error, probably as much as 1000 per cent. Fig. 64 FLANGE TAP CONNECTIONS 151 ORIFICE METER MEASUREMENT INSTRUCTIONS TO METER ATTENDANTS One of our most important operations is the measure- ment of gas, and it is essential that meter charts and records reach the Chart Department in the best possible condition. A little -more attention and care on your part can prevent a great many errors that may not be noticed by the one cal- culating the charts who is not familiar with local operations. You are responsible for the condition of your charts and we wish to call your attention to the following points in order that you may be properly instructed. No doubt you are now observing many of these points, but if they are carried out in the following order, uniform methods will result in better charts. Changing Orifice Meter Charts Make a zero differential check and wait a few minutes to see that the pen remains on the zero line, if it does not, report at once or adjust and make note of findings. Release pens from chart by means of pen lifter, remove center nut and slip chart off without touching pens. Wind the clock and put on new chart im- mediately, seeing that the chart is properly centered and that the differential or red ink pen is on the correct time line. Hold chart in place and tighten chart nut. Blot the re- moved chart carefully and fill in complete information: Name of Meter, Location, Disc Number, actual time and date chart was put on and removed. Always sign your name in full. Never turn chart by hand to fill in record and make it appear complete when such is not the case. Never allow 24 hour charts to run for more than one day, except in case of absolute necessity, and when this does occur, make notes on chart to identify corresponding lines of each day. DO NOT SAVE CHARTS UP FOR SEVERAL DAYS, BUT MAIL THEM IN PROMPTLY EACH DAY. When charts, envelopes or other supplies are needed, make request on face of chart, and give name and address for mailing. Do not allow your supplies to run out. 152 ORIFICE METER MEASUREMENT When inking pens, use just enough ink to fill the pen, being careful not to confuse the colors. Always use red ink in the long or differential pen. Do not allow excess ink to run down the pen arms or accumulate on the pen lifter where it will smear chart. See that the pens make a good clear line, and that the colors do not get mixed. Pens should be cleaned occasionally to prevent deposits of dried ink and dust. Before leaving meter, make sure that the pens are touch- ing the chart and marking properly. Also, that the chart is securely clamped and turning with the clock. Waiting a few minutes after the chart is changed and observing these conditions will save a great deal of trouble and bad measure- ment. See that the gauge is protected from wind and rain, and if you are unable to protect it, call attention to the mat- ter by a note on the chart. When unusual conditions are indicated by the chart, determine the cause, if possible, and give full information. In case the pens get off the chart, notify the nearest man in charge by telephone, as soon as possible. Do not allow gauge to remain out of repair WITHOUT CALLING AT- TENTION TO IT. On all other meters same care should be given to charts. Check readings on index carefully and make subtraction to get last delivery. If no delivery is shown, find the reason and note same on chart. Any suggestions for improvement that may occur to you will be welcomed in the form of a letter. Meter Dept. 153 ORIFICE METER MEASUREMENT TESTING APPARATUS Inspector's Test Pump for Static Pressure Gauges Fig. Fig. 65 illustrates an inspector's test gauge and pump with carrying case. The use of a test gauge of this kind is recommended for testing Static Pressure Springs rather than the use of a portable dead weight tester. The pressure is applied by filling the pump with oil and forcing the oil into the static spring as well as into the spring of the test gauge. 154 ORIFICE METER MEASUREMENT Vacuum Gauge Test Pump Fig. 66 The pump shown here represents a very efficient apparatus for testing vacuum gauges. The mercury column is graduated in inches and centi- meters. A small set screw is provided on the mercury reservoir for running out the mercury and for accurately ad- justing the level of the mercury to the zero point on the scale. This mercury gauge requires about 2j/ Ib. of mercury. 155 ORIFICE METER MEASUREMENT Pocket Gauge for Testing Differential Gauges This siphon or "U" gauge which can be conveniently carried about with the mer- cury retained is adapt- ed for testing differen- tial gauges. The scale is graduated in inches up to 100 inches of water. The fittings at the top joining the inlet tube to the glass are made with two swivel joints, permitting the glass and scale to be turned both laterally and vertically. When the gauge is in use the glass is turned away from the inlet tube, thus opening the gas way at the top, and the outlet cap is loosened. When it is to be placed in the case, the glass is turned in toward the inlet tube, closing the gas way and the outlet cap is screwed down, thus preventing the escape of the mercury at either side. This apparatus can be used to advantage in locations where it is not advisable to install a permanent gauge for checking differential pressures and where the quantity measured is comparatively small. The short length of col- umns makes it impractical for use where it is desired to have differential gauge check closer than one-half an inch of water pressure. For accurate determinations or checks it is always necessary to read both columns of the gauge in order to obtain a correct differential. 156 Fig. 6? ORIFICE METER MEASUREMENT Siphon or "U" Gauges For testing gauges whose maximum range is less than 20 inches, the type of gauge shown in Fig. 68 may be used, using water as a fluid. These are the most convenient low pressure gauges in use, being portable and simply screwed to the piping wherever it is desired to take the pressure. They consist of a U shaped glass tube with a metal goose- neck, in sizes from 4 inch to 36 inch. Between the columns of this tube is set a scale graduated in inches and tenths, or pounds and ounces,, as desired. A bent brass tube, or goose-neck, is connected to the "U" tube at the top and runs down the side to the gas connection. When used, the gauge is filled with water or mercury to the center of the scale, which is zero. The gauge is con- nected to the test tap and the pressure is turned on. The liquid will fall below zero on the inlet side of the "U" tube and rise on the opposite side the same distance. The distance between the two levels of the liquid, as shown by the scale, will indicate the amount of pressure in inches and tenths or in pounds and ounces, according to the graduation. While the gauge is in use the down- ward motion of the liquid in one column, due to the pressure of the gas or air should equal the rise of liquid in the opposite col- umn. In case the liquid, after being set at zero, should not drop on the pressure side as much as it rises on the other side, it is an indication that the glass tubes are not of equal diameter, and both columns must be read, their sum being the true pressure. 157 Fig. 68 SIPHON OR "U" GAUGE ORIFICE METER MEASUREMENT Permanent Gauge for Testing Differential Gauges In stations where there are two or more meters which are being used to measure very large quantities of gas and where it is desirable to obtain very accurate measurements, the installation of a permanent test gauge is recommended. The total range of the test gauge being equal to the maximum range of the differential gauges in inches of water. When using a test gauge made of two columns of small bore glass tubing, the gauge should be calibrated between the water levels in the columns or both columns of the gauge must be read, as a very small difference in bore of the tubes will make an ap- preciable difference in the results if only one column of the U tube is being read and doubled. Furthermore, it is quite possible to obtain inaccurate results due to the water ad- hering to the surface of the tube on the high pressure side. A reasonable interval of time should be allowed for the water to seek its proper levels before reading. The difficulties of the U tube consisting of two small bore columns may be obviated by using a U tube in which a high pressure side is made of a chamber of considerable area as compared with the low pressure column. That is, if the area of the high pressure chamber or column is 99 times as great in area as the low pressure column, the water will drop 1 inch on the high side while it rises 99 inches in the low pressure column for a total differential of 100 inches due to the fact that the high pressure chamber is much greater in area than the low pressure column. The rise of 99 inches in the low pressure column may be uniformly divided into 100 parts, then each division of y^ of an inch would represent one inch of water differential. The water in the low pressure column rises Y/O f an mcn while the water in the high pressure column falls j^j of an inch. If the high pressure column is 1000 times the area of the low pressure column the use of a scale marked in inches would be sufficiently accurate as the total error in 100 inches would be only y^ of an inch 158 ORIFICE METER MEASUREMENT in water pressure. Furthermore, in an installation of this kind the water adhering to the sides of either column is so small when compared to the total volume of water that the error in levels would not be appreciable and thus the neces- sity of waiting for the water to seek its level is eliminated. Either of the above mentioned gauges may be used for testing under pressure, if the fittings and material are of sufficient strength to withstand the pressure. Portable Water Differential Test Gauges Fig. 69 shows portable water gauges constructed on the above principle for testing gauges in the field under working conditions. Fig. 69 Courtesy of H. R. Pierce Fig. 70 Courtesy of L. E. Ingham 159 ORIFICE METER MEASUREMENT Fig. 70 also shows a small portable outfit which may be used for testing the differential range of gauges. Tube A is attached to the high pressure test tap. The small cylinder made of tin or copper is partly filled with water as is also the rubber tubing B and the portion of the glass tube C. The glass tube C is etched or marked and the mark is held at the zero point of the scale attached to the small cylinder. The water is added to the cylinder or through the glass tube C until its level reaches the etched mark. When pressure is exerted on the low pressure portion of the gauge, the same pressure acts also on the water in the cylinder causing water to rise on the glass tube C. For instance, if it was desired to test the gauge at 10 inches differential, the glass tube C is raised until the etched mark is level with the 10 inch mark on the scale. When pressure is exerted on the high pressure side and the differential pen arm rests at the 10 inch mark on the chart the glass tube is moved either up or down until the water surface reaches the etched mark and the check reading is obtained from the scale at a point opposite the mark. It is evident that when the water reaches the etched mark that the surface of the water in the cylinder is at the same point as at the beginning of the test or the zero position, for the combined volume of the water in the cylinder below the zero mark, in the rubber tube B, and in the glass tube C up to the etched mark is the same as at the beginning of the test. A very small difference may be caused by elasticity of the rubber tubing B but since the area of the cylinder is very many times as great as the area of the rubber tubing the effect on the zero position is negligable. When this ap- paratus is attached to the low pressure side for testing under a vacuum the connection is made with the top of the glass tube C instead of being made at the top of the cylinder. 160 PART FOUR MEASUREMENT OF GAS AND AIR AIR AND GAS MEASUREMENT COEFFICIENTS MULTIPLIERS FOR REVISION OF COEFFICIENTS - OSAGE NATION SPECIFICATIONS-TABLES OF C v - ORIFICE CAPACITIES COMPARATIVE MEASURE- MENTSATMOSPHERIC PRESSURE VARIATIONS- GAS CONTRACTS MULTIPLE ORIFICE METER INSTALLATION INSTALLING AND TESTING GAS AND AIR METERS READING CHARTS. The Differential and Static Pressure Gauge records on a chart the differential pressure existing between the pressure connections, and the static pressure at one of the connections. These factors, with the known area of the orifice, enable the operator to determine the flow from the formula: Q = C VAP Where <2 = the quantity of gas or air passing the orifice. The result is expressed in cubic feet per hour. C = the Hourly Orifice Coefficient for gas or air. The value of this term remains the same for each in- stallation and basis of measurement. h = the Differential Pressure existing between the two pressure connections expressed in inches of water head, this value being recorded graph- ically on the chart of the recording differen- tial gauge. 161 MEASUREMENT OF GAS AND AIR P = the Static Pressure expressed in absolute units, being equal to the atmospheric pressure (which is recorded on the chart) plus the gauge pressure. The value of the gauge pressure is also recorded on the chart. The value of the Hourly Orifice Coefficient C in the above formula is found on Pages 173 to 184, computed for various diameters of orifice and diameters of pipe, these values having been determined by exhaustive experimental and practical tests in comparison with actual displacement. The extensions of the values of V hP have been compiled and are given in the book entitled "Pressure Extensions" pub- lished by this Company. Example One hour reading (Air Flow) : Diam. of Pipe = 4 inches. Diam. of Orifice = 2 inches. Average Differential reading h = 25 inches. Base and Flowing Temperature = 60 degrees fahr. Average Gauge Pressure p = 90 pounds. Hourly Orifice Coefficient C= 1019.4 for 2 inch orifice in a 4 inch line (Page 173). Quantity per hour, Q= 1019.4 V 25 X (90 + 14.4) Orifice Pressure = 1019.4X51.088 = 52079 cu. ft. Coefficient. Extension. Using the same data, when measuring gas at a 4 oz. Pressure Base, the Hourly Orifice Coefficient C is 1293.7 for a 2 inch orifice in a 4 inch line, (Table 29, Page 175), Orifice Pressure (2=1293.7 V25X (90+14.4) = 1293.7X51.088 Coefficient. Extension. or the volume passing through the orifice = 66093 cubic feet per hour. Therefore the Quantity per hour flowing in the lines is equal to the Coefficient of the Disc multiplied by the Pres- sure Extension. 162 MEASUREMENT OF GAS AND AIR In the formula V = C v -^2gH the differential head or the difference in pressure between the upstream side of the ori- fice and the downstream side of the orifice is expressed in feet head of flowing fluid and as it is not practical to register this value directly, the differential head is recorded on the chart in inches of water. Using the same data as used on Page 80 in determination of the value of the air coefficient, the details of the develop- ment of the values of the constants for the formula for the flow of air and gases are given below. 1 foot head of air at 32 deg. fahr. (492 degrees absolute) at 14.7 Ib. per sq. in. = .015534 inches of water. Therefore, 1 inch of water -64.375 feet of air at 32 de- grees at 14.7 Ib. (1^.015534 = 64.375). Since the volume increases as the pressure decreases, 1 inch of water = 946.31 feet of air at 32 degrees at 1 Ib. per sq. in. absolute. (64.375X14.7 = 946.31). Referring to Part 2, we find that the volume decreases as the temperature decreases. 1 inch of water = 1.9234 feet of air at 1 deg. fahr. absolute at 1 Ib. per sq. in. absolute. (946.31^492 = 1.9234). For any pressure and temperature : 1 inch of water = - feet of air at T degrees ab- solute at P Ib. absolute, according to the Law of Perfect Gases. Where T = Temperature in deg. fahr. absolute. P = Pressure in pounds per square inch absolute. For gas, as the Specific Gravity G increases the weight per cubic foot increases, and the differential head in feet head of gas decreases, and vice versa. 1.9234Z\ , 1 inch of water = - feet head of gas. PG 163 MEASUREMENT OF GAS AND AIR MEASUREMENT OF GAS AND AIR 1 9234 Th Then h inches of water = feet head of gas, PG But H feet of gas equals h inches of water, 1 9234 hT Therefore, H = - in feet head of gas, PG Where H = differential pressure expressed in feet head of flowing gas. h = differential in inches of water. Substituting this value of H in the formula r , we obtain ; v=c |2 g X1.9234^ 1113 Iff \ PG VPG Where V = actual velocity of gas passing the orifice, at temperature T and pressure P. C v = coefficient of velocity. g = acceleration due to gravity in feet per second, per second, (32.2 used on Page 80). 1 . 9234 = feet head of air at 1 deg. fahr. absolute at 1 Ib. per sq. in. absolute equivalent to one inch of water. h = differential in inches of water. T = temperature in deg. fahr. absolute. p= pressure in pounds per sq. in. absolute. G = specific gravity of gas (air = l) The quantity of gas passing through the orifice is equal to the area of the orifice in square feet multiplied by the velocity in feet per hour 144 X V 165 MEASUREMENT OF GAS AND AIR Where Q\ = actual quantity of gas passing the orifice in cubic feet per hour, at the pressure and tem- perature of the flowing gas. 0.7854 m tne formula from the preceding page, Q 1 = 19Md 2 XV. X 11.13 C d = 218.6 Since the gas is measured under standard conditions of Base Temperature and Pressure Base it is really measured by weight by the introduction of these terms. From the Law of Perfect Gases, Page 59, (in this case Q is substituted for v) T b T Where Pb = Pressure Base in pounds per square inch absolute. P = actual pressure of flowing gas in pounds per square inch absolute. Q = volume of gas passing orifice expressed in cubic feet at a Pressure Base P b and a Base Tem- perature TV 166 MEASUREMENT OF GAS AND AIR Fig. 72 50 INCH DIFFERENTIAL GAUGE, FLANGE CONNECTIONS 167 MEASUREMENT OF GAS AND AIR Qi = volume in cubic feet passing the orifice at actual Flowing Temperature and Pressure of the gas or air. r fc = Base Temperature in deg. fahr. absolute. T = Flowing Temperature in deg. fahr. absolute. Then Q = QiX- P b T Substituting the value of Qi from the previous formula Qi = 218.6 C v d 2 \j^7^ in this expression. Q= 218.6 C v d * PG P b ' >T h \h P In this formula 218.6 is a constant depending on the units of measurements. On Page 81 the constant for a fifteen minute period is 54.65 being one fourth of 218.6 the constant for one hour. The net result of these factors is expressed in the formula : TG Where Q = Quantity of gas passing the orifice expressed in cubic feet at a Base Temperature and a Pressure Base. K = Constant dependent upon the value of g, weight of water per cubic foot and units of measure- ment. C v = Coefficient of Velocity. The value of this term depends upon the location of the pressure connections in the main line, diameter of ori- fice, internal diameter of pipe and ratio of differential to line pressure. 168 MEASUREMENT OF GAS AND AIR d = diameter of orifice in inches. r 6 = Base Temperature in deg. fahr. absolute = 460+ Base Temperature in degrees fahrenheit on an ordinary thermometer scale. P b = Pressure Base in pounds per square inch absolute. P = pressure of flowing gas in pounds per square inch absolute = atmospheric pressure + gauge pres- sure p. When gas is measured under a vacuum, P = atmospheric pressure (in pounds per square inch) 0.4908 X (inches of mercury vacuum). h = Differential Pressure between the connections expressed in inches of water. T = temperature of flowing gas in deg. fahr. absolute = 460+ temperature in degrees fahrenheit. G = Specific Gravity of gas compared with air, which is 1. The Hourly Coefficient C in Tables 27 to 38 = 218.6 C v d 2 Tb _ P b ^TG Thus it is seen that the Coefficient is dependent upon the values used for K, C V) d, P b , T b , T and G. Where the conditions of flow are defined, this formula is simplified as follows: (Table 27, Page 173). T b = 60 deg. fahr. = 520 degrees absolute. P 6 = 01b. above atmosphere (14.4 Ib.) =14.4 Ib. per sq. in. absolute. r = 60 deg. fahr. = 520 deg. absolute. G = 1.00 c _ 218.6 ^n_ 21S6 520 C/ C = 346.2 C v d 2 . 169 MEASUREMENT OF GAS AND AIR F i g 73 ORIFICE, FLANGES AND 100 INCH DIFFERENTIAL GAUGE INSTALLATION. PIPE TAP CONNECTIONS. NOTE BY-PASS BETWEEN GAUGE LINES 170 MEASUREMENT OF GAS AND AIR The Coefficients in Tables 27 to 38 are prepared for pipe of standard dimensions (4.026, 6.065, 8.071 and 10.191 inches internal diameter), for installations where the pressure con- nections are made 2J/2 diameters upstream and 8 diameters downstream. These Hourly Orifice Coefficients were based on the original Hourly Orifice Coefficients (changed for pres- sure base only). They were calculated from the various values of C v obtained by inspection from a smooth curve, drawn as a mean through the values of C v obtained by tests as described in Part 3. The values of C v were obtained by using the constants used in this article, which constants should be used for calculating orifice coefficients where the conditions do not vary materially from the conditions of the tests. The values of C v contained on Pages 208 to 210 were cal- culated from a formula* which was derived several years later from four points on a curve drawn in a similar manner to the above. These values do not vary more on an average than grQ- of one percent from the values of C v previously mentioned, some of the values being slightly lower and some higher, than those used in the original calculations. The published values of the air and gas Coefficients are retained in this volume in their original form. Their reli- ability is not increased by any change except by a series of tests much more comprehensive than those previously con- ducted. Future tests will no doubt take into consideration the humidity of the atmosphere, and the slight variations due to pressures, differentials, specific gravity, viscosity of the fluid, etc. When such tests are made, it is hoped that they shall be conducted by an authority superior to the operator and the manufacturer and that their findings may be binding upon both the buyer and the seller, such as standard weights and measures are today. *By H. R. Pierce. 171 MEASUREMENT OF GAS AND AIR In calculating Hourly Orifice Coefficients for all other dimensions of pipe not contained in the original tables, the use of the values of C v from Pages 208 to 210 is recom- mended due to the fact that any two parties will be sure to use the same value, and ,thus avoid any controversy which may arise over a value obtained by inspection from a plotted curve. Coefficients for pipes of other internal diameters may be obtained by substituting in the previous formula the proper values for the pressures, temperatures, etc., using the value of 218.6 for K. Example Coefficient for a !}/ inch orifice in a pipe 5.188 inches in diameter is desired. Pressure Base 8 oz. above an atmospheric pressure of 14.4 Ib. per square inch. Base and Flowing Temperature 60 deg. fahr. Specific Gravity 1.00. P b - 14.4+0.5 = 14.9 Ib. per sq. in. absolute. T b = 60+460 -520 deg. fahr. absolute. G -1.00 X diameter of orifice -4- diameter of pipe =.2891. C,= .6414, Page 208. C = 218.6 C v d 218.6X.6414X1.5X1.5X520 14.9V520X1 Fig. 74 PIPE. SADDLE 172 MEASUREMENT OF GAS AND AIR Table 27 HOURLY ORIFICE COEFFICIENTS FOR GAS AND AIR Pressures taken 2^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.4 Ib. Base and Flowing Temperature 60 deg. fahr. Pressure Base lb._(14.4 Ib. Abs.) Specific Gravity 1.00 Values of C in Q = C VhP where Q = quantity of gas or air passing the orifice in cubic feet per hour. DIAMETER OP DIAMETER OF PIPE LINE ORIFICE INCHES 4" 6" 8" 10" y* 53.20 52.88 52.72 52.67 % 83.55 % 121.1 119.6 119.1 118.8 1/8 166.2 1 219.2 214.3 212.7 212.0 l/^ 280.4 1M 1% 350.6 430.1 338.3 '334.'2 332.5 519.9 493.2 484.6 480.6 j5/ 621.8 1/4 738.2 681.0 665.0 657.5 jT/ 870.2 2 1019.4 904.1 876.4 863.8 gi/g 1189.3 2/4 1382.5 1169.1 1121.8 1100.9 g3^ 1610.8 23/2 1856.2 1480.4 1401.2 1368.8 2% 2146.8 **Xo 2M 2481.9 1851.2 1718.5 1670.0 2^ 2860.2 3 3296.2 2287.2 2078.8 2004*9 3J4 2806.9 2485.1 2371.9 31^ 3428.1 2950.5 2788.3 3?4 4166.8 3474.7 3243.3 4 5050.4 4070.0 3742.9 4/4 6103.8 4752.4 4296.0 41^ 7358.2 5519.5 4909.0 4/4 6411.7 5583.7 5 7407.7 6330.8 8575.8 7164.0 &A 9906.9 8071.2 5/4 11406.5 9098.9 6 13131.1 10225.4 6/4 11481.2 6^ 12885.9 6^4 14448.0 7 16196.3 734 18125.0 73^ 20249.0 173 MEASUREMENT OF GAS AND AIR Table 28 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14 .4 Ib . Base and Flowing Temperature 60 deg . f ahr . Pressure Base Ib. (14.4 Ib. Abs.). Specific Gravity .600 Values of C in Q = C VhP where Q= quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE URIFICE INCHES 4" 6" 8" 10 ;/ H 68.68 68.27 68.06 68.00 % 107.90 % 156.3 154.4 153.8 'l53.4 % 214.6 282.9 '276.'7 274.6 '273.'7 m 362.0 m 452.6 '486.8 431.5 429.2 IH 555.3 m 671.2 636^7 625.6 620^5 i*A 802.8 IK 953.0 879.1 858.5 848.8 VA 1123.4 2 1316.1 1167.2 1131.4 1115.'2 2y s 1535.4 2H 1784.8 1509^3 1448.2 1421 .'2 2*/s 2079.5 2y 2 2396.3 1911. '2 1808 .'9 1767.2 2 5 / 8 2771.5 2% 3204.1 2390^0 2218.' 6 2155.9 2 7 A 3692.5 u /& 3 4255.3 2952.7 2683.8 2588.3 3U 3623.7 3208.3 3062.2 u /4 3^ 4425.6 3809.1 3599.7 3% 5379.3 4485.8 4187.1 *-'/4 4 6520.0 5254.4 4832.0 4M 7880.0 6135.3 5546.1 4M 9499.4 7125.7 6337.3 4^ 8277.5 7208.5 5 9563.3 8173.0 5k' 11071.3 9248.6 5 l /2 12789.7 10419.8 &A 14725.7 11746.6 6 16952.1 13200.9 Q 1 A 14822.1 v/4. &A 16634.3 &/A 18652.1 v /4 7 20909.1 7U 23399 . 2 1 / 4r 7^2 26141.3 1 / 4 174 MEASUREMENT OF GAS AND AIR Table 29 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.4 Ib. Base and Flowing Temp. 60 deg. fahr. Pressure Base 4 oz.J14.65 Ib. Abs.) Specific Gravity .600 Values of C in Q =C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE ORIFICE INCHES 4" Q" 8" 10" 1 A 67.5 67.1 66.9 66.8 5 A 106.0 H 153.7 151.8 151.2 150.8 210.9 i 278.1 272.0 269.8 269.1 ji/g 355.8 11^ 444.9 429.4 424.1 421.9 liHj 545.9 i/^ 659.8 '625 .'9 615.0 609.9 1^8 789.1 1/4 936.8 864.2 844.0 834.4 l/^ 1104.3 2 1293.7 1147.4 1112.2 1096.2 2/ / s 1509.3 234 1754.5 1483 .'7 1423.' 6 1397.0 2^8 2044.1 K/ / o 2355.6 1878.7 1778 .'2 1737.1 2^8 2724.4 2% 3149.7 2349.4 2180.' 8 2119.'3 g.TX 3629 8 3 4183.0 2902.5 2638.2 2544.3 3M 3562.2 3153.7 3010.1 31^ 4350.4 3744.4 3538.5 3% 5287.9 4409.6 4116.0 4 6409.2 5165.0 4749.9 4/ 7746.1 6031.0 5451.8 4/^ 9337.9 7004.5 6229.6 4^ 8136.8 7084.7 5 9400.8 8034.1 5/4 10883.2 9091.4 51^ 12572.3 10242.7 5/ 14475.4 11547.0 6 .... 16664.0 12976.5 gi/ 14570.1 6^ 16350.0 6^ 18335.1 u/4 7 20553.8 23001 . 5 7i/ 25697.0 175 MEASUREMENT OF GAS AND AIR Table 30 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.4 Ib. Base and Flowing Temp. 60 deg. fahr. Pressure Base 8 oz._(14.9 Ib. Abs.) Specific Gravity .600 Values of C in Q =C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE ORIFICE INCHES 4" 6" 8" 10" K *A 66.4 104 2 66.0 65.8 65.7 H j2 151.1 207 4 149.3 148.3 148.2 \y% 273.4 349 8 267.4 265.3 , 264.5 V4 IH 437.4 536 7 422.1 417.0 414.8 iy 2 l*A l*A 1% 648.7 775.8 921.0 1085.7 615.3 849.6 604.6 829.7 599.7 820.3 2 2% 1271.9 1483 9 1128.0 1093.4 1077.7 2% 2% 1724.9 2009 7 1458.7 1399.6 1373.5 2y 2 2% 2% 2% 3 3X sy 2 &A 4 4M 4j| 2315.9 2678.5 3096.6 3568.6 4112.5 1847. 1 2309.8 2853.6 3502.1 4277. 1 5198.8 6301.2 7615.6 9180 6 1748.2 2144.1 2593.7 3100.6 3681.3 4335.3 5078.0 5929.4 6886 5 1707.9 2083.5 2501.4 2959.4 ' 3478.9 4046.6 4669.9 5360.0 6124 7 4% 5 5M 5 l / 2 &A 6 Q 1 A 7999.7 9242.4 10699.8 12360.5 14231.5 16383.3 6966.6 7898.7 8938.3 10070.2 11352.4 12757.9 14324 7 VA &A 7 VA V/2 16076.1 18026.2 20207.5 22613.9 25264.0 176 MEASUREMENT OF GAS AND AIR Table 31 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2J^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.4 Ib. Base and Flowing Temp. 60 deg. fahr. Pressure Base 10 oz. (15.025 Ib. Abs.) Specific Gravity .600 Values of C in Q =C VhP where Q =quantity of gas passing the orifice in cubic feet per hour DIAMETER OF DIAMETER OF PIPE LINE ORIFICE INCHES 4" 6" 8" 10" 1 65.8 103 4 65.4 65.2 65.2 H 7 A 149.8 205 7 148.0 147.4 147.0 \YC, 271.2 346 9 265.2 263.0 262.3 VA i 3 A 433.7 532 2 418.6 413.5 411.4 1 1 A m 1% $ 2y 8 2*A 2% 643.3 769.4 913.3 1076.6 1261.3 1471.6 1710.6 1993 610.2 842.5 ins.'e 1446.5 599.6 822*8 1084.3 1388.0 594.7 813.5 1068.7 1362.1 2y 2 2 5 A 2% 2 7 A 2296.6 2656.2 3070.9 3538.9 1831.7 2290.6 1733.7 2126.3 1693.7 2066.2 3 3M 3 1 A 3H 4M 4^ 4% 5 5^ 4078.3 2829.9 3473.0 4241.5 5155.5 6248.8 7552.2 9104.2 2572.1 3074.8 3650.7 4299.2 5035.8 5880.1 6829.2 7933.2 9165.5 10610.8 2480.6 2934.8 3450.0 4013.0 4631.0 5315.4 6073.7 6908.6 7833.0 8863.9 5U 12257 7 9986.4 &A 14113 1 11258.0 6 Q 1 A 16247.0 12651.8 14205.5 Q 1 A &A 15942.4 17876.2 7 20039.4 7M 22425.8 7^ 25053.9 177 MEASUREMENT OF GAS AND AIR Table 32 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2 l /% diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.4 Ib. Base and Flowing Temp 60 deg. fahr. Pressure Base 1 lb^(15.4 Ib. Abs.) Specific Gravity .600 Values of C in Q =C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE ORIFICE INCHES 4" Q" 8" 10" 1 A 5 A % % iy* 64.2 100.9 146.2 200.6 264.6 338.5 63.8 144.4 258.7 63.6 143.8 256.8 63.6 143.4 256.0 8 423.2 519 3 408.4 403.4 401.4 8 \*A 627.7 750 6 595.4 585.0 580.2 1% iy 8 2 2% &A 2% 891.1 1050.4 1230.6 1435.7 1668.9 1944 5 822.0 1091.4 1411.3 802.8 1057.9 1354.2 793.7 1042.7 1328.9 2 1 A 2% 2240.7 2591 6 1787.1 1691.4 1652.4 &A 2% 3 3^ 3y 2 &A 4 4^ 43^ 4% 2996.1 3452.8 3979.0 2234.8 2761.0 3388.4 4138.2 5030.0 6096.6 7368.3 8882.5 2074.5 2509.5 2999.9 3561.8 4194.5 4913.2 5736.9 6662.9 7740.0 2015.9 2420.2 2863.3 3366.0 3915.2 4518.3 5185.9 5925.8 6740.4 5 5^ 5^ 5% 6 8942.3 10352.4 11959.2 13769.6 15851 3 7642.3 8648.1 9743.2 10983.8 12343.7 Q l /i 13859.6 &A 6% 7 7H 7 1 A 15554.2 17440.9 19551.4 21879.7 24443.8 178 MEASUREMENT OF GAS AND AIR Table 33 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2*^ diameters upstream and 8 diameters downstream. Atmospheric "Pressure 14 .4 Ib . Base and Flowing Temperature 60 deg . fahr . Pressure Base 1^ lb^(15.9 Ib. Abs.). Specific Gravity .600 Values of C in = C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE (JRIFICE INCHES 4" 6" 8" 10" X to x Vv 62.2 97.7 141.6 194 3 61.8 'l39.9 61.6 139.3 61.6 138^9 I iy s ix 1 3 /C 256.2 327.8 409.9 502 9 250.6 395.6 248.7 390^8 247.9 388.7 IK 1% 1M 1% 2 2y s 2 1 A 2% 607.9 727.0 863.1 1017.4 1191.9 1390.6 1616.4 1883 3 576'. 6 '796^2 1057.1 1366.9 566.6 777.6 1024^7 1311.6 562.0 768.7 1009^9 1287 .'l 2y 2 2 5 / 8 &A 2 7 A 2170.3 2510.1 2901.9 3344 2 1730.9 2164^5 1638.2 2009^3 1600.5 1952^5 3 3M 3\4 3853.9 2674.4 3281.9 4008.1 2430.6 2905.6 3449.8 2344.1 2773.3 3260.1 3M 4 4J4 4^ 4M 4871.8 5904.9 7136.6 8603.2 4062.6 4758.7 5556.5 6453.4 7496.6 3792.1 4376.2 5022.9 5739.5 6528 4 5 8661.1 7402.0 5K 10026.9 8376 . 1 5 1 A 5 3 /X 6 11583.1 13336.5 15352.9 9436.8 10638.4 11955.5 6 1 A 13423.8 sy 2 15065.0 6M 16892.5 7 18936.6 7K 21191.7 7K 23675.2 179 MEASUREMENT OF GAS AND AIR Table 34 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken]23^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14 .4 Ib . Base and Flowing Temperature 60 deg. fahr . Pressure Base 2 Ib. (16.4 Ib. Abs.). Specific Gravity .600 Values of C in Q = C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER c >F PIPE LINE INCHES 4" 6" 8" 10" K % % % 60.3 94.7 137.3 188.4 59.9 135.6 59.8 135. i 59.7 134.7 lYs 248.4 317 8 243.0 241.1 240.3 IX 1*2 397.4 487 6 383.5 378.8 376.9 i l A 1% 589.4 704.9 559.1 549.3 544.8 IK 1J4 836.7 986 4 771.9 753.8 745.3 2 2V* 1155.6 1348 2 1024.9 993.4 979.1 * 1 A 2 8 2 1 A 2&i 1567.1 1825.9 2104.1 2433 5 1325.3 1678.1 1271.6 1588 .'3 1247.9 1551.7 2H 2H 3 &A VA 3% 4 4^ 4^ 4M 5 5^ 2813.4 3242.2 3736.4 2098.5 2592.6 3181.8 3885.9 4723.3 5724.9 6919.0 8340.9 1948.0 2356.5 2817.0 3344.6 3938.8 4613.6 5387.1 6256.7 7268.0 8397.1 9721.2 1893.0 2272.6 2688.7 3160.7 3676.5 4242.8 4869.7 5564.5 6329.4 7176.3 8120.7 &A 11229.9 9149.1 5% 12929.9 10314.1 6 6M 14884.8 11591.0 13014.5 VA 6M 7 7^ VA 14605.7 16377.5 18359.3 20545.6 22953.3 180 MEASUREMENT OF GAS AND AIR Table 35 HOURLY ORIFICE COEFFICIENTS FOR GAS AND AIR Pressures taken 2J^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.7 Ib. Base and Flowing Temperature 60 deg. fahr. Pressure Base oz. (14.7 Ib. Abs.). Specific Gravity 1.00 Values of C in Q =C VhP where Q = quantity of gas or air passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER o F PIPE LINE ORIFICE INCHES 4" 6" 8" 10" y* 52.11 51.80 51.64 51.60 b /s 81.84 H 118.6 117.2 116^7 116.4 7 A 162.8 214.7 209^9 208^4 207^7 IX 274.7 IK 343.4 331.4 327^4 32$. 7 IX 42-1.3 i l A 509.3 483.1 '474.7 470^8 1 5 A 609.1 1% 723.1 667.1 651.4 644.1 IX 852.4 2 998.6 885.6 858.5 846.2 2Y 8 1165.0 2 1 A 1354.3 1145.2 1098.9 1078.4 2% 1577.9 &A 1818.3 1450.2 1372.6 1340.9 2H 2103.0 2% 2431.2 1813.4 1683.4 1635^9 2 7 /8 2801.8 3 3228.9 2840 .'5 2036.4 1964 'O 3M 2749.6 2434.4 2323.5 m 3358.1 2890.3 2731.4 3M 4081.8 3403.8 3177.1 4 4947.3 3986.9 3666.5 4M 5979.2 4655.4 4208.3 4^ 7208.0 5406.9 4808.8 4^ 6280.9 5469.7 5 7256.5 6201 . 6 fyi 8400.8 7017.8 &A, 9704 . 7 7906.5 5% 11173.7 8913.2 6 12863.1 10016.7 y 11246.9 V/2 1262,2.9 &A 14153.1 7 15865.8 VA 17755.1 7^ 19835.8 181 MEASUREMENT OF GAS AND AIR Table 36 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2> diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.7 Ib. Base and Flowing Temperature 60 deg. fahr. Pressure Base 4 oz. (14.95 Ib. Abs.). Specific Gravity .60 Values ofCinQ =C Vhp where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER o F PIPE LINE ORIFICE INCHES 4" 6" 8" 10" V* 66.15 65.76 65.56 65.50 % 103.9 % 150.6 148.7 148.1 147.7 1/K 206.7 1 272.6 266^5 264^5 263.6 \\/n 348.7 1/4 436.0 420.7 415.6 413.5 l/^ 534.8 \y 2 646.5 613.3 602.6 597.6 l/^ 773.2 \y 918.0 846.8 '826.9 817.6 \T/Q 1082.1 2 1267.6 1124.2 1089.8 1074.1 2^8 1478.9 2% 1719.1 1453.' 8 1395.0 1369.0 2% 2003.0 2 1 A 2308.2 1840^9 1742.4 1702.1 2669.5 2% 3086.2 2302^0 2137.0 2076^6 2 7 / 8 3556.7 3 4098". 8 2844.1 2585.0 2493.1 3/4 3490.4 3090.2 2949.5 31^2 4262.8 3668.9 3467.3 3% 5181.4 4320.8 4033.0 4 6280.2 5061.0 4654.3 4/4 7590.1 5909.6 5342.1 43^ 9149.9 6863.5 6104.3 4/4 7972.9 6943.3 5 9211.5 7872.3 10664.0 8908.4 Pji/ 12319.2 10036 . 5 go/ 14184.0 11314.5 6 4 16328.5 12715.3 6M 14276.9 6>2 16023.6 6^ 17966.1 7 20140.1 7K 22538.4 25179.6 182 MEASUREMENT OF GAS AND AIR Table 37 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.7 Ib. Base and Flowing Temperature 60 deg fahr. Pressure Base 8 oz. (15.2 Ib. Abs.). Specific Gravity .60 Values ofCinQ =C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE ORIFICE INCHES 4" 6" 8" 10" K 5 /s 65.07 102 2 64.67 64.48 64.42 % 7% 148.1 203 3 146.3 145.7 145.3 iu 268.1 342.9 262.1 260.1 259.3 IM IH 1MI i% 428.8 526.0 635.9 760 5 413.8 '603.2 408.7 592.7 406.7 587.8 IH VA 920.9 1064 3 832.9 813.3 804.2 2 2 1 A 1246.8 1454 6 1105.8 1071 . 9 1056.5 2X 2*A 1690.9 1970 1 1429.9 1372.0 1346.5 2 l / 2 2 5 A 2270.2 2625 6 1810.6 1713.7 1674.1 2% 2 7 A 3035.5 3498 2 2264.1 2101.8 2042.5 3 3 1 A 4031.4 2797.4 3433 2542.5 3039 4 2452.1 2900 9 3H 4192 7 3608 6 3410 2 m 4 5096.2 6176 9 4249.7 4977 8 3966.7 4577.7 4M 4l| 7465.2 8999 4 5812.4 6750 6 5254.2 6003 . 9 4M 7841 8 6829.1 5 9060 7742.9 5^ 5^ 5M 6 6M 6^ 6^ 7 7M 10488.6 12116.6 13950.7 16060.0 8761 . 9 9871.5 11128.4 12506.1 14042.0 15760.1 17670.6 19808.8 22167.7 7^ 24765.5 183 MEASUREMENT OF GAS AND AIR Table 38 HOURLY ORIFICE COEFFICIENTS FOR GAS Pressures taken 2J^ diameters upstream and 8 diameters downstream. Atmospheric Pressure 14.7 lb. Base and Flowing Temperature 60 deg. fahr. Pressure Base 10 oz. (15.325 lb. Abs.). Specific Gravity .60 Values ofCinQ =C VhP where Q = quantity of gas passing the orifice in cubic feet per hour. DIAMETER OF DIAMETER OF PIPE LINE URIFICE INCHES 4" 6" 8" 10" H 64.54 64.15 63.95 63.89 H 101.4 % 146.9 145.1 144.5 144. 1 % 201.6 265.9 260^0 '258^0 '257^2 iy* 340.1 m 425.3 410.4 405.4 '403^3 i% 521.7 . . VA 630.7 '598^3 587.9 583.0 1% 754.3 */ o m 895.5 826.1 806^7 797.6 ! 7 /8 1055.6 2 1236.6 1096.7 1063.1 i047^9 2y s 1442.7 2 1 A 1677.1 1418.2 1360^8 1335.5 m 1954.0 m 2251.7 1795^8 1699^8 1660^5 2 5 / 8 2604.2 &A 3010.7 2245^6 2084^7 2025^8 2y 8 3469.6 3 3998.5 2774^5 2521^7 2432.1 &A 3405.0 3014.6 2877.3 &A 4158.5 3579.2 3382.4 &A 5054.6 4215.1 3934.4 4 6126.5 4937.2 4540.4 1 A 7404.3 5765.0 5211.4 1 A 8926.0 6695.5 5955.0 4% 7777.8 6773.4 5 8986.1 7679.7 5M 10403.1 8690.4 5^ 12017.8 9790.9 5% 13836.9 11037.6 6 15929.0 12404.1 &A 13927.5 Q 1 A 15631.5 u / A 6M 17526.4 7 19647.3 1\4 21986.9 1 /4 VA 24563.5 184 MEASUREMENT OF GAS AND AIR 185 MEASUREMENT OF GAS AND AIR SPECIFIC GRAVITY Specific gravity is the ratio between the density of a body and the density of some body chosen as a standard. In stating the specific gravities of gases, air is generally taken as a standard. It is very necessary to know the specific gravity of a gas when one is measuring gas by an orifice meter. The most accurate instrument for use in obtaining the specific gravity, is the specific gravity balance. The effu- sion method cannot be relied upon for accurate determina- tions unless tests have been made in comparison with the specific gravity balance with various specific gravities of gas. A complete description of the methods and a full set of effusion method tables are contained in our Hand Book of Casinghead Gas. MULTIPLIERS FOR REVISION OF COEFFICIENTS It was noted that each Table of Hourly Orifice Co- efficients was calculated upon certain values for Base and Flowing Temperature, Gravity, Pressure Base, Atmospheric Pressure and location of connections. It would require a library of unlimited size to present coefficients to meet all conditions of flow measurement which an orifice meter will satisfactorily handle. In this volume we present the Tables of Hourly Orifice Coefficients which will meet the most frequent requirements and Tables of Multipliers for use in converting the coefficients to meet almost any condition. Let C w = new Coefficient desired. Tb n = proposed new Base Temperature in degrees fahrenheit absolute. Pbn = proposed new Pressure Base in pounds per square inch absolute. r w = new or actual Flowing Temperature of gas in degrees fahrenheit absolute. 186 MEASUREMENT OF GAS AND AIR G M = new or actual Specific Gravity of gas being measured. C n = 218.6 C v d 2 Tbn _^ C n 218.6 C v d 2 T bn P b C 218.6 C\ ITG Therefore, the Multiplier = Example Diameter of pipe, 6 inches. Diameter of ori- fice, 3 inches. Pressure taken 2]/^ diameters upstream and 8 diameters downstream. Proposed new Base Temperature, 50 deg. fahr. (T bn = 5lQ deg. absolute). Proposed new Pressure Base, lJ/ Ib. above an average atmosphere pressure of 14.4 Ib. (P bn = 15.9 Ib. absolute). New or actual Flowing Temperature, 50 deg. fahr. (T w = 510 deg. absolute). New or actual Specific Gravity, G M = 0.65 In Table 29 the Coefficient 2902.5 is based upon a Base Temperature T b and Flowing Temperature T of 60 deg. fahr. (520 deg. absolute), Pressure Base 4 ounces (P b = 14.65 Ib. absolute), and Specific Gravity G= 0.600 Substituting these values in the above formula. 510X14.65 \ 520X15.9 \510X0.65 187 MEASUREMENT OF GAS AND AIR New Coefficient C n = 2902.5 X .87679 = 2544.9 or using the Multiplier Tables 39, 42, 43 and 45. Multiplying Factor Table 42, 50 deg. Base Temperature =.9808 Table 39, l}4 Ib. Pressure Base (Coefficient in Table based on 4 oz.) =.9214 Table 43, 50 deg. Flowing Temperature = 1 . 0098 Table 45, Specific Gravity .65 (Coefficient in Table based on .600) = . 9608 The New Coefficient C H = 2902.5 X .9808 X .9214 X 1 .0098 X .9608 = 2544.9 Multiplier for Change of Pressure Base C = P P ^~, in which TT~ ~ is the multiplier. bn "bn C n = new or revised Coefficient. C = Coefficient determined upon Pressure Base P b . Pb = Pressure Base in pounds per square inch abso- lute upon which coefficient C was calculated. P 6n = new or proposed Pressure Base in Ib. per square inch absolute. Example Pressures taken 2^ diameters upstream and 8 diameters downstream. Pipe Diameter = 4 inches. Base and Flowing Tempera- ture = 60 deg. fahr. Orifice Diameter = 2 inches. Atmospheric Pressure = 14.4 Ib. Pressure Base = 8 ounces. Specific Gravity = .600. 188 MEASUREMENT OF GAS AND AIR The Coefficient 1293.7 in Table 29 fulfills all conditions with the exception of Pressure Base (4 oz.) upon which the table was prepared. In Table 39 the Multiplying Factor for 8 oz. Pressure Base = .9832 (for converting Coefficient from 4 oz. Pressure Base, 14.65 Ib. absolute, to an 8 oz. Pressure Base) which is 14.4+0.25 14.65 equal to C n = 1293.7 (Orifice Coefficient from Table 29) X .9832=1271.9 In case that the atmospheric pressure is different from 14.4 and if a different value is specified in the contract, see following subject. Multiplier for Atmospheric Pressure Changes C n = C in which - is the multiplier. A n +p b A n +p b C M = new or revised Coefficient. C = Coefficient based upon an atmospheric pressure A . A = Atmospheric Pressure in pounds per square inch upon which the Orifice Coefficient C was cal- culated. The value used in Tables in this book is 14.4 or 14.7 pounds per square inch. p b = Pressure Base (pressure expressed in pounds per square inch above atmosphere). A = actual or new Atmospheric Pressure in Ib. per square inch which equals ordinary Barometer reading in inches of mercury times 0.4908. Example Pressures taken 2J^ diameters upstream and 8 diameters downstream. 189 MEASUREMENT OF GAS AND AIR Pipe Diameter = 4 inches. Base Temperature = 60 deg. fahr. Orifice Diameter =1 inch. Flowing Temperature = 60 deg. fahr. Pressure B ase = 4 oz . above Atmospheric Pressure = 12.0 atmospheric pressure. Ib. Specific Gravity = .600. Therefore, the proposed Pressure Base is 12.0+ 0.25 (4 oz.) = 12.25 Ib. (absolute). The Coefficient 278.1 in Table 29 fulfills all condi- tions with the exception of the Atmospheric Pressure (14.4 Ib.) upon which the Table was calculated. In Table 41 the Multiplying Factor is 1.1959 for con- verting the Coefficient from 14.4 Ib. to 12 Ib. Atmospheric Pressure at 4 oz. Pressure Base. _. 14.4+0.25 14.65 This factor 1.1959 = = 12.0+0.25 12.25 C n = 278.1 (Orifice Coefficient from Table 29) X 1.1959 = 332.6. See note at foot of Page 196, also Page 221. In cases where the Pressure Base also changes or is dif- ferent from that of the Table, A+p b The multiplier is Where p bn is the new Pressure Base expressed in pounds per square inch above the atmospheric pressure. 190 MEASUREMENT OF GAS AND AIR Multiplier for Base Temperature Changes T T C n = C -~r , in which = is the multiplier. *b 1 b C w = new or revised Coefficient. C = Coefficient based upon Base Temperature T b . or revised Base Temperature in degrees fahrenheit absolute. r 6 = Base Temperature upon which Coefficient C was calculated. Tables are usually prepared for 60 deg. fahr. (520 deg. absolute) Example Pressures taken 2J/2 diameters upstream and 8 diameters downstream. Pipe Diameter = 8 inches. Base Temperature = 80 deg. fahr. Orifice Diameter = 4 inches. Flowing Temperature = 60 deg. fahr. Pressure Base = 4 ounces. Atmospheric Pressure 14.4 Ib. Specific Gravity =.600. The Coefficient 5165 in Table 29 fulfills all condi- tions with the exception of the Base Temper- ature (60 deg. fahr.) upon which the Table was calculated. In Table 42 the multiplying factor is 1.0385. 460+80 540 This factor = - = - 460+60 520 C w = 5165 (Orifice Coefficient from Table 29) X 1.0385 = 5363.9 191 MEASUREMENT OF GAS AND AIR Multiplier for Changes in Flowing Temperature nr [Y C n = C \~7jT in which \~jT is the multiplier. * * -* n C n = new or revised Coefficient. C = Coefficient calculated upon the Flowing Tempera- ture T. T = Flowing Temperature in degrees fahrenheit ab- solute upon which the Coefficient C was calculated. Tables are usually prepared using a Flowing Temperature of 60 deg. fahr. (520 deg. absolute). T n = actual or new Flowing Temperature. Example Pressures taken 2J/2 diameters upstream and diameters downstream. Pipe Diameter = 6 inches. Base Temperature = 60 deg. fahr. Orifice Diameter = 4 inches. Flowing Temperature = 90 deg. fahr. Pressure Base = pounds. Atmospheric Pressure = 14.4 Ib. Specific Gravity = 1.00 The Coefficient 5050.4 in Table 27 fulfills all con- ditions with the exception of the Flowing Temperature which is 60 deg. fahr. In Table 43 the multiplying factor is .9723 for con- verting Coefficient from 60 deg. to 90 deg. fahr. Flowing Temperature. ^.. , 460+60 520 This factor = \ =\ M60+90 X 550 C n = 5050.4 (Orifice Coefficient, Table 27) X.9723 = 4910.5. 192 MEASUREMENT OF GAS AND AIR Multiplier for Specific Gravity Changes r A = Affective area of flowing stream in square feet. a = Area of orifice in square feet. C = Coefficient of contraction, friction, etc. (Vc or Eff.) d = Diameter of orifice in inches. D = Diameter of pipe in inches. V = Velocity of the flowing fluid feet per hour. g = Acceleration of gravity at L and E. H = Differential across orifice in feet of flowing fluid. h = Differential across orifice in inches of water at 60 deg. fahr. PI= Absolute pressure of flowing fluid pounds per square inch. PZ = Absolute pressure base or (reference pressure). p = Atmospheric pressure absolute pounds per square inch. TI= Absolute temperature of flowing fluid. T 2 = Absolute temperature base or (reference tem- perature) . L = Average latitude of the field in which the gas is measured. E = Average elevation above sea level of the field in which the gas is measured. G = Specific gravity of gas flowing. (Compared to air at 14.4 Ib. and 60 deg. fahr.) X = D X = The sign of multiplication. * H. R. Pierce. 202 MEASUREMENT OF GAS AND AIR Assumptions in Figuring Hourly Gas Coefficients to be Used with Orifice Meters. Measuring Gas in the Osage Nation C. For orifice meters where differential taps are taken 1 inch upstream from face of orifice disc and 1 inch from downstream face of orifice disc and pressure connection taken from downstream connection, is found from this formula : C = .606+1.25 (X-Al) 2 Where X = Al or more. For any value of X below .41, C is equal to a constant .606 (by Weymouth). C. For orifice meters when differential taps are taken 2.5 pipe diameters above upstream face of orifice disc, and downstream connection is made 8 pipe diameters below upstream face of disc. Pressure connection taken at upstream tap. C is found from this formula; C= (.58925 +.2725^ .825 X 2 +1.75 X 3 ) 1 cubic foot water at 60 deg. fahr. weighs 62.37 Ib. 1 cubic foot air at 14.4 Ib. and 60 deg. fahr. weighs .0748378 Ib. fi2 Q7 Therefore, =833.40237 feet of air at 14.4 .0748378 and 60 deg. fahr. to equal in weight 1 foot of water at 60 deg. fahr. Therefore, 1 inch of water = 833 ' 4Q23 ' = (69.45019 12 feet of air at 14.4 Ib. and 60 deg. fahr. to equal in weight 1 inch of water at 60 deg. fahr.) 203 MEASUREMENT OF GAS AND AIR g=(by Pierce's formula) 32.0894 (1 + .0052375 Sin 2 L) (I .00000009575) I, = 36 deg. 45 min. N. Latitude which is considered the average for the Osage., =1,000 ft. above sea level, (considered average elevation for Osage) . # = 32.1465. /> = 14.4 Ib. per square inch absolute. P 2 = 10 oz. above atmospheric pressure or 15.025 Ib. per square inch absolute. Considering the average atmospheric pressure to be 14.4. r x = 60 deg. fahr. or 519.6 deg. absolute fahr. 7^ = 60 deg. fahr. or 519.6 deg. absolute fahr. Showing all figures used in deduction of Air and Gas Con- stant to be used in the Osage. Q = A V A=aC 3.1416 d 2 a = 4 X 144 7 = 3600 V2X32.1465# 14.4 H = h 69.45019 PI 519.6 4 7 = 3600 i2X32. 1465 /* 69.45019 P l 519.6 /3.1416 d 2 \ V 4X144 / rr: \ 3600 C ^2X32.1465 // 69.45019 ) X P! 519.6/ 204 MEASUREMENT OF GAS AND AIR Simplifying, we get : Q = 218.422 Cd 2 \ h - I PI T P To reduce Q to any desired P 2 or T 2 , we introduce = 218.422 - 2 ^ CW 2 ^U - 1 T) Canceling , we have *l = 218.422 -?- Cd 2 \lh * Considering T 2 and T lt 60 deg. fahr. or 519.6 deg. ab- solute fahr., we have Q = 218.422 4978.872045014 cd 2 ' ^h P l Gravity of Gas 1. Pressure Base of oz. = 14.4 Ib. Absolute. Q = 345.755 Cd 2 V h PI Pressure Base of 4 oz. = 14.64 Ib. Absolute. Q = 340.087 Cd 2 V h P l Pressure Base of 6 oz. = 14.75 Ib. Absolute. Q = 337.551 Cd 2 V h PI Pressure Base of 8 oz. = 14.9 Ib. Absolute. Q = 334.152 Cd 2 ^ h P 1 205 MEASUREMENT OF GAS AND AIR Pressure Base of 10 oz. = 15.025 Ib. Absolute. Q = 331.373 Cd 2 V h P l Pressure Base of 1 Ib. = 15.4 Ib. Absolute. Q = 323.303 Cd 2 V h P l Pressure Base of 2 Ib. = 16.4 Ib. Absolute. Q = 303.590 Cd 2 V h P To get Gas Constant divide air constant by the square root of the gravity of gas. The inside diameter of standard pipe used in orifice meter settings, as a rule, is as follows : D for 4 inch pipe = 4.026. D f or 6 inch pipe = 6. 065. D for 8 inch pipe = 8.Q71 . D for 10 inch pipe = 10. 191. D for 12 inch pipe = 12.000. Please note on meter setting reports if other than standard pipe is used giving inside diameter, weight, etc. In reporting size of orifice please give nearest standard size with the actual micrometer of orifice to ~ inch. Special For taps 2.5 and 8 diameters with 10 oz. Pressure Base the one hour gas coefficient is derived from this formula : 331.373 d 2 (.58925+.2725X-.825^ 2 +1.75^ 3 ) Vspecific gravity of the gas. For taps 1 inch and 1 inch with 10 oz. Pressure Base the one hour gas coefficient is derived from this formula : 331.373 d 2 [.606+1.25 ( X-Al ) 2 }" Vspecific gravity of the gas. 206 MEASUREMENT OF GAS AND AIR 207 MEASUREMENT OF GAS AND AIR Table 46 VALUES OF C, FOR 2^ AND 8 DIAMETER CONNECTIONS Diameter Orifice G=.58925+. 2725 ^-. X = From Page 203 Actual Internal Diameter Pipe X c. X c. X c v X c. .151 .617612 .201 .624903 .251 .633345 .301 .644251 .152 .617755 .202 .625056 .252 .633534 .302 .644503 .153 .617897 .203 .625209 .253 .633735 .303 .644757 .154 .618040 .204 .625364 .254 . 633816 .304 . 645012 .155 .618183 .205 . 625518 .255 .634109 .305 . 645269 .156 . 618326 .206 .625674 .256 .634303 .306 .645527 .157 .618469 .207 .625829 257 .634498 .307 .645787 .158 .618612 .208 .625985 258 . 634693 .308 . 646049 .159 . 618755 .209 . 626142 .259 . 634890 .309 . 646312 .160 .618898 .210 .626299 .260 .635088 .310 . 646577 .161 .619041 .211 .626457 .261 . 635287 .311 .646843 .162 .619184 .212 .626615 .262 .635487 .312 .647111 .163 .619327 .213 . 626774 .263 .635688 .313 . 647381 .164 .619470 .214 .626934 .264 .635890 .314 . 647652 .165 . 619613 .215 .627094 .265 .636094 .315 .647925 .166 .619756 .216 .627255 .266 .636298 .316 .648199 .167 .619900 .217 . 627416 .267 .636504 .317 .648475 .168 . 620043 .218 .627578 .268 . 636711 .318 .648753 .169 .620187 .219 . 627741 .269 .636919 .319 .649033 .170 .620330 .220 .627904 .270 .637128 .320 .649314 .171 . 620474 .221 .628068 .271 .637338 .321 .649597 .172 . 620618 .222 628232 .272 . 637549 .322 . 649881 .173 .620762 .223 .628398 .273 .637762 .323 .650168 .174 .620906 .224 .628564 .274 .637976 .324 .650456 .175 .621050 .225 .628730 .275 .638191 .325 .650746 .176 .621195 .226 .628898 .276 .638408 .326 . 651038 .177 .621340 .227 .629066 .277 .638625 .327 . 651331 .178 .621485 .228 .629235 .278 .638844 .328 .651626 .179 .621630 .229 .629404 .279 . 639065 .329 .651923 .180 . 621776 .230 .629575 .280 .639286 .330 .652222 .181 .621922 .231 .629746 .281 .639509 .331 .652523 .182 .622068 .232 .629918 .282 . 639733 .332 .652825 .183 . 622214 .233 .630090 .283 .639958 .333 .653130 .184 .622360 .234 .630264 .284 .640185 .334 .653436 .185 .622507 .235 .630438 .285 .640413 .335 .653744 .186 .622654 .236 .630613 .286 . 640642 .336 . 654054 .187 .622802 .237 .630789 .287 .640873 .337 .654365 .188 .622950 .238 .630966 .288 . 641105 .338 . 654679 .189 .623097 239 .631144 .289 . 641338 .339 . 654995 .190 . 623246 .240 .631322 .290 .641573 .340 .655312 .191 .623394 .241 .631501 .291 .641809 .341 .655631 .192 .623543 .242 .631681 .292 . 642047 .342 . 655953 .193 . 623693 .243 .631863 .293 . 642286 .343 .656276 .194 .623843 .244 .632045 .294 . 642526 .344 .656601 .195 . 623993 .245 .632227 .295 .642768 .345 .656928 .196 .624143 .246 .632412 .296 .643012 .346 .657257 .197 . 624294 .247 .632596 .297 .643257 .347 . 657589 .198 .624446 .248 . 632782 .298 .643503 .348 .657922 .199 .624598 .249 .632969 .299 .643751 .349 . 658257 .200 .624750 .250 .633156 .300 .644000 .350 .658594 See Page 171 208 MEASUREMENT OF GAS AND AIR Table 47 VALUES OF C v FOR 2y 2 AND DIAMETER CONNECTIONS C,=.58925+.2725X-.825 *+1.75 X* X = ^ From Page 203 Pipe X c v X c v X c v X c. .351 .658933 .401 .678704 .451 .704876 .501 .738762 .352 .659274 .402 .679160 .452 .705473 .502 .739527 .353 .659617 .403 .679619 .453 .706074 .503 .740296 .354 .659963 .404 .680080 .454 .706679 .504 .741069 .355 . 660310 .405 .680545 .455 .707286 .505 .741845 .356 .660660 .406 .681011 .456 .707896 .506 .742625 .357 .661011 .407 . 681481 .457 . 708509 .507 . 743409 .358 .661365 .408 .681953 .458 .709125 .508 .744196 .359 .661720 .409 .682427 .459 .709745 .509 . 744987 .360 .662078 .410 .682904 .460 .710368 .510 .745782 .361 .662438 .411 .683384 .461 .710994 .511 .746580 .362 .662800 .412 .683866 .462 .711623 .512 .747382 .363 .663165 .413 . 684351 .463 .712255 .513 .748188 .364 . 663531 .414 .684839 .464 .712891 .514 .748998 .365 .663899 .415 .685330 .465 .713530 .515 .749811 .366 .664270 .416 .685823 .466 .714172 .516 .750628 .367 .664643 .417 .686319 .467 .714817 .517 .751449 .368 .665018 .418 .686818 .468 .715466 .518 .752273 .369 . 665396 .419 . 687320 .469 .716118 .519 .753102 .370 .665775 .420 .687824 .470 .716773 .520 .753934 .371 .666157 .421 .688331 .471 .717431 .521 .754770 .372 .666541 .422 .688841 .472 .718093 .522 .755610 .373 .666927 .423 .689353 .473 .718758 .523 .756453 .374 .667316 .424 .689869 .474 .719426 .524 .757301 .375 .667707 .425 . 690386 .475 .720098 .525 .758152 .376 .668100 .426 .690908 .476 .720773 .526 .759008 .377 .668496 .427 .691431 .477 .721451 .527 .759867 .378 .668893 .428 .691958 .478 .722133 .528 .760730 .379 . 669293 .429 .692487 .479 . 722818 .529 .761596 .380 .669696 .430 .693020 .480 .723506 .530 .762467 .381 .670101 .431 .693555 .481 . 724198 .531 .763342 .382 . 670507 .432 .694093 .482 .724893 .532 .764220 .383 .670917 .433 . 694634 .483 .725592 .533 .765103 .384 .671329 .434 . 695178 .484 .726294 .534 .765990 .385 .671743 .435 . 695724 .485 .726999 .535 .766880 .386 .672160 .436 .696274 .486 .727708 .536 .767775 .387 . 672579 .437 .696827 .487 .728420 .537 .768673 .388 .673001 .438 .697382 .488 .729136 .538 .769575 .389 . 673424 .439 . 697941 .489 .729855 .539 .770482 .390 .673851 .440 .698502 .490 .730578 .540 .771392 .391 . 674279 .441 .699066 .491 .731304 .541 .772306 .392 .674711 .442 . 699634 .492 .732034 .542 .773225 .393 .675144 .443 . 700204 .493 .732768 .543 .774147 .394 .675580 .444 .700777 .494 .733504 .544 .775074 .395 .676019 .445 .701354 .495 .734245 .545 .776004 .396 .676460 .446 .701933 .496 .734989 .546 .776939 .397 .676904 .447 .702516 .497 . 735736 .547 .777878 .398 . 677350 .448 . 703101 .498 .736487 .548 .778821 .399 .677799 .449 .703690 .499 .737242 .549 .779768 .400 . 678250 .450 .704281 .500 .738000 .550 . 780719 See Page 171 209 MEASUREMENT OF GAS AND AIR Table 48 VALUES OF C v FOR 2^ AND 8 DIAMETER CONNECTIONS iameter Hfice G=.58925-K2725 X-.825 XM-1.75 X 3 X = From Pagej203 Actual Internal Diameter Pipe X c. X c v X c v X c. .551 .781674 .601 .834925 .651 .899827 .701 .977693 .552 .782633 .602 . 836104 .652 .901253 .702 .979391 .553 .783597 .603 . 837288 .653 .902684 .703 .981096 .554 .784564 .604 .838477 .654 . 904120 .704 .982806 .555 .785536 .605 . 839671 .655 .905562 .705 . 984521 .556 .786512 .606 .840869 .656 .907009 .706 . 986243 .557 .787492 .607 .842072 .657 .908461 .707 .987970 .558 .788477 .608 .843280 .658 . 909918 .708 .989703 .559 .789465 .609 .844492 .659 .911380 .709 .991442 .560 .790458 .610 .845709 .660 .912848 .710 .993187 .561 . 791455 .611 . 846931 .661 .914321 .711 .994937 562 . 792456 .612 . 848158 .662 .915799 .712 .996693 .563 . 793462 .613 .849389 .663 .917283 .713 .998455 .564: . 794472 .614 .850626 .664 .919772 .714 1.000223 , .565 . 795485 .615 .851866 .665 .920266 .715 1.001997 .566 .796504 .616 .853112 .666 .921766 .716 1.003777 .567 .797527 .617 .854363 .667 .923271 .717 1.005162 .568 .798553 .618 .855618 .668 . 924781 .718 1 . 007354 .569 .799585 .619 .856879 .669 .926297 .719 1.009151 .570 .800620 .620 . 858144 .670 .927818 .720 1.010954 .571 .801660 .621 .859414 .671 .929344 .721 1.012763 .572 .802704 .622 .860689 .672 .930876 .722 1.014578 .573 .803753 .623 .861969 .673 .932413 .723 1.016399 .574 .804806 .624 .863253 .674 .933956 .724 1.018226 .575 .805863 .625 .864543 .675 .935504 .725 1.020059 .576 .806925 .626 .865838 .676 .937058 .726 1.021898 .577 .807991 .627 .867137 .677 .938616 .727 1.023742 .578 .809062 .628 .868441 678 .940181 .728 1.025593 .579 .810137 .629 .869751 .679 . 941751 .729 1.027450 .580 .811216 .630 .871065 .680 .943326 .730 1.029312 .581 .812300 .631 .872384 .681 .944907 .731 1.031181 .582 .813388 .632 . 873708 .682 .946493 .732 1.033056 .583 .814481 .633 .875037 683 .948085 .733 1.034936 .584 .815578 .634 .876371 .684 .949683 .734 1.036823 .585 .816680 .635 .877711 .685 .951285 .735 1.038716 .586 .817786 .636 .879055 .686 .952894 .736 1.040615 .587 .818897 .637 .880404 .687 .954508 .737 1 . 042520 .588 .820012 .638 .881758 .688 .956127 .738 1.044431 .589 .821132 .639 .883118 .689 .957753 .739 1.046349 .590 .822256 .640 .884482 .690 .959383 .740 1.048272 .591 .823385 .641 .885851 .691 .961019 .741 1.050201 .592 .824518 .642 .887226 .692 .962661 .742 1.052137 .593 . 825656 .643 .888606 .693 .964309 .743 1.054079 .594 .826798 .644 . 889990 .694 .965962 .744 1.056027 .595 .827945 .645 .891380 .695 .967621 .745 1.057981 .596 . 829097 .646 .892775 .696 .969286 .746 1.059941 .597 .830253 .647 .894175 .697 .970956 .747 1.061907 .598 .831414 .648 .895580 .698 . 972631 .748 1.063880 .599 . 832580 .649 .896991 .699 .974313 .749 1.065859 .600 . 833750 .650 898406 .700 . 976000 .750 1.067844 See Page 171 210 MEASUREMENT OF GAS AND AIR Table 49 VALUES OF C v FOR FLANGE CONNECTIONS C v =. 606+1.25 (X-A1) 2 X = Diameter of Orifice Actual Internal Diameter of Pipe From Page 203 X c. X c v X C v X c. .150 .606000 .451 .608101 .501 .616351 .551 .630851 .200 .606000 .452 .608205 .502 .616,580 .552 .631205 .250 .606000 .453 . 608311 .503 .616811 .553 .631561 .300 .606000 .454 .608420 .504 .617045 .554 .631920 .350 . 606000 .455 .608531 .505 .617281 .555 .632281 .400 .606000 .456 .608645 .506 .617520 .556 .632645 .405 . 606000 .457 .608761 .507 .617761 .557 .633011 .408 .606000 .458 .608880 .508 .618005 .558 .633380 .409 .606000 .459 .609001 .509 . 618251 .559 .633751 .410 . 606000 .460 .609125 .510 .618500 .560 .634125 .411 .606001 .461 .609251 .511 .618751 .561 .634501 .412 .606005 .462 609380 .512 .619005 .562 .634880 .413 .606011 .463 .609511 .513 .619261 .563 .635261 .414 .606020 .464 .609645 .514 . 619520 .564 .635645 .415 .606031 .465 .609781 .515 .619781 .565 .636031 .416 . 606045 .466 .609920 .516 .620045 .566 .636420 .417 . 606061 .467 . 610061 .517 . 620311 .567 .636811 .418 .606080 .468 .610205 .518 .620580 .568 . 637205 .419 .606101 .469 .610351 .519 .620851 .569 .637601 .420 .606125 .470 .610500 .520 .621125 .570 .638000 .421 .606151 .471 .610651 .521 .621401 .571 .638401 .422 .606180 .472 . 610805 .522 .621680 .572 . 638805 .423 .606211 .473 .610961 .523 .621961 .573 .639211 424 .606245 .474 .611120 .524 . 622245 .574 .639620 .425 . 606281 .475 .611281 .525 .622531 .575 .640031 .426 .606320 .476 .611445 .526 .622820 .576 .640445 .427 .606361 .477 .611611 .527 .623111 .577 .640861 .428 . 606405 .478 .611780 .528 . 623405 .578 .641280 .429 .606451 .479 .611951 .529 .623701 .579 .641701 .430 . 606500 .480 .612125 .530 . 624000 .580 . 642125 .431 .606551 .481 .612301 .531 .624301 .581 .642551 .432 . 606605 .482 .612480 .532 . 624605 .582 .642980 .433 .606661 .483 . 612661 .533 .624911 .583 .643411 .434 . 606720 .484 .612845 .534 .625220 .584 .643845 .435 . 606781 .485 .613031 .535 .625531 .585 .644281 .436 .606845 .486 .613220 .536 . 625845 .586 .644720 .437 .606911 .487 .613411 .537 . 626161 .587 .645161 .438 .606980 .488 .613605 .538 .626480 .588 .645605 .439 .607051 .489 .613801 .539 .626801 .589 .646051 .440 .607125 .490 .614000 .540 .627125 .590 .646500 .441 .607201 .491 . 614201 .541 .627451 .591 .646951 .442 .607280 .492 . 614405 .542 .627780 .592 .647405 .443 .607361 .493 .614611 .543 .628111 .593 .647861 .444 . 607445 .494 .614820 .544 .628445 .594 .648320 .445 .607531 .495 .615031 .545 . 628781 .595 . 648781 .446 .607620 .496 .615245 .546 .629120 .596 .649245 .447 .607711 .497 .615461 .547 . 629461 .597 .649711 .448 .607805 .498 .615680 .548 .629805 .598 .650180 .449 .607901 .499 .615901 .549 .630151 .599 .650651 .450 -.608000 .500 .616125 .550 .630500 .600 .651125 211 MEASUREMENT OF GAS AND AIR Table 50 VALUES OF C v FOR FLANGE CONNECTIONS C 9 = .606 + 1.25 (X-Al) 2 X = Diameter of Orifice From Page 203 Actual Internal Diameter of Pipe X c. X c v X c, .601 .651601 .651 .678601 .701 .711851 .602 .652080 .652 .679205 .702 .712580 .603 .652561 .653 .679811 .703 .713311 .604 .653045 .654 .680420 .704 . 714045 .605 .653531 .655 .681031 .705 .714781 .606 . 654020 .656 .681645 .706 .715520 .607 .654511 .657 .682261 .707 .716261 .608 .655005 .658 .682880 .708 .717005 .609 . 655501 .659 .683501 .709 .717751 .610 .656000 .660 .684125 .710 .718500 .611 .656501 .661 .684751 .711 . 719251 .612 .657005 .662 .685380 .712 . 720005 .613 .657511 .663 .686011 .713 .720761 .614 .658020 .664 .686645 .714 .721520 .615 .658531 .665 .687281 .715 . 722281 .616 . 659045 .666 .687920 .716 .723045 .617 .659561 .667 .688561 .717 .723811 .618 .660080 .668 .689205 .718 .724580 .619 . 660601 .669 . 689851 .719 .725351 .620 .661125 .670 .690500 .720 .726125 ' .621 .661651 .671 .691151 .721 . 726901 622 .662180 .672 .691805 .722 .727680 .623 .662711 .673 . 692461 .723 . 728461 .624 . 663245 .674 .693120 .724 .729245 .625 .663781 .675 . 693781 .725 . 730031 .626 . 664320 .676 .694445 .726 .730820 .627 . 664861 .677 .695111 .727 .731611 .628 .665405 .678 . 695780 .728 . 732405 .629 . 665951 .679 .696451 .729 .733201 .630 .666500 .680 .697125 .730 .734000 .631 .667051 .681 .697801 .731 .734801 .632 . 667605 .682 .698480 .732 .735605 .633 . 668161 .683 .699161 .733 .736411 .634 . 668720 .684 .699845 .734 .737220 .635 .669281 .685 .700531 .735 .738031 .636 .669845 .686 . 701220 .736 .738845 .637 .670411 .687 .701911 .737 . 739661 .638 .670980 .688 .702605 .738 .740480 .639 . 671551 .689 .703201 .739 .741301 .640 .672125 .690 . 704000 .740 .742125 .641 .672701 .691 . 704701 .741 .742951 .642 .673280 .692 . 705405 .742 .743780 .643 .673861 .693 .706111 .743 .744611 .644 .674445 .694 .706820 .744 .745445 .645 .675031 .695 .707531 .745 .746281 .646 .675620 .696 .708245 .746 .747120 .647 .676211 .697 .708961 .747 .747961 .648 . 676805 .698 .709680 .748 .748805 .649 .677401 .699 . 710401 .749 .749651 .650 .678000 .700 .711125 .750 .750500 212 MEASUREMENT OF GAS AND AIR Table 51 HOURLY ORIFICE COEFFICIENTS FOR GAS AND AIR Pressures taken at Flanges, Standard Pipe, Page 206. Atmospheric Pressure 14.4 Base and Flowing Temperature 60 deg. fahr. Pressure Base Ib. Specific Gravity 1.000 Diameter of Orifice Inches DIAMETER OF PIPE LINE 4" 6" 8" 10" 12" H 52.3819 52.3819 52.3819 52.3819 52.3819 5 A 81.8467 81.8467 81.8467 81.8467 81.8467 % 117.859 117.859 117.859 117.859 117.859 % 160.430 160.420 160.420 160.420 160.4120 I 209.528 209.538 209.528 209.528 209.528 VA 265.183 265.183 265.183 265.183 265.183 VA 327.387 327.387 327.387 327. 387 327.387 m 396.138 396.138 396.138 396.138 396.138 VA 471.437 471.437 471.437 471.437 471.437 i*A 553.283 553.283 553.283 553.283 553.283 IH 642.484 641.678 641.678 641.678 641.678 VA 741.338 736.620 736.620 736.620 736.620 2 851.136 838.110 838.110 838.110 838.110 zy* 973.238 946.148 946.148 946.148 946.148 2 1 A 1109.22 1060.74 1060.74 1060.74 1060.74 2*A 1260.77 1181,86 1181.86 1181.86 1181.86 2y 2 1429.76 1309.56 1309.55 1309.55 1309.55 2 5 A 1618.20 1445.33 1443.78 1443.78 1443.78 &A 1828.25 1590.71 1584.55 1584.55 1584.55 2 7 A 2062.25 1746.52 1731.88 1731.88 1731.88 3 2322.68 1913.62 1885.75 1885.75 1885.75 3M 2285.45 2213.14 2213.14 3213.14 3 1 A 2714.51 2569.67 2566.71 3566.71 VA 3210.19 2964.62 2946.48 3946.48 4 3782.97 3403.11 3352.44 3353.44 4M 4444.48 3890.68 3784.97 3784.59 4^ 5207.37 4433.47 4251.65 4343.93 *H 5038.25 4758.16 4727.47 5 5712.42 5308.43 5268.67 5M 6463.97 5906.84 5784.11 VA 7301.55 6558.11 6368.75 &A 8234.42 7267.37 6995.86 6 9272.46 8040.14 7669.03 6M 8882.33 8393.05 VA 9800.26 9169.10 6M 10800.57 10004 . 55 v 'X' 7 11890.4 10903.11 ?M 13077.1 11869.7 VA 14368.7 13909.7 8 15331.9 &A 17917.6 9 31018.7 Based on 345.755 d 2 [-606 +1.25 (Z-.41) 2 ] 213 Page 205. MEASUREMENT OF GAS AND AIR INCHES MERCURY VACUUM GAUGE PRESSURE -POUNDS LINE PRESSUR^ MAXIMUM CAPACITY OF 20 DIFFERENTIAL GAUGE CUBIC FT. PER HC/UR ft O ft ftOfti ft o ftftftft ft ft O' SO^ftftOtv O OftftOOOOQi ftftftOO ft ft ftftooo ft o ftftft OftOO* Jft-0-0- >Ooo ftOOO ft ftOOft ft Ofto6 O O OOOO O OOOO O OOOO O ft OO ft Oft O ft OOOO ft OftOO O O OOOO O OOOO O ftOOO OOOO O OOO r^Hi ! oooo o o oooo o o I ooo o o o o oooo oo MAXIMUM CAPACITY OF 10 DIFFERENTIAL GAUGE ) ( / DIAMETERS OF ORIFICES -INCHES MEASUREMENT OF GAS AND AIR 2 -s s 3 * a ? * s GAUGE PRESSURE -POUNDS LINE PRESSURE MAXIMUM CAPACITY OF 100 DIFFERENTIAL GAUGE CUBIC FT. PER HOUR ggg ggggg ggggggg S SoooooooSS Sooo g Sggggggggg ggSSS g gggSS gggg ggggg g ggggg gggfg ggggg g ggggg ggggg ggggg gggggggg OOOO OOOOO O O OOOO OOOOO OOOOO 00 OOOO O OOOO O OOOO O O OOOO 00 r..o~ 2 ,..o uj 0.00,50 ooooo ooooo o o o goo g o oog g oooo gSgggggg T J S.-S U !! i U . I; t|l W / .3 11 *l| S / ja as" !H?/1 ^fl l^^i^-iJt I ."S jiS S S I 1 > 111 i/l l 1 ^ l|l ^ v ; g 3 : ' E 6 ' ^ J ,' J o 2 J 5 V 13 m X u S ill u. ^.Ss: v ec t> ll tin size of or re Line P thi with Orifice CAPACITY III S D MAXIMUM CAPACITY OF 20 DIFFERENTIAL GAUGE CUBIC FT. PER HOUR o ooooo o ooooo oooog ggggg gggggggggg ggggg g ssss s gsgss ggggg ssssg s ssgsg ggggg s^ssg s gsgsg S - ---S cj wr-a>i- ^ ^| ^s 3 "SN Hr P*3 1 "^1 1 ^ 1 O sng m i? ip "*S J _,,-$* ^1 * ^ T. ">, ^ . * 3'. -!! l *JJl w -j ^ -XVJ "S Jj*!**^ t| ^ n| -ffl | '^JSJI v> > -^ -* 1 S N ^ -^ n 'cu*. j| -s 4 * 216 MEASUREMENT OF GAS AND AIR i ? 1 a s g 5 g GAUGE PRESSURE -POUNDS LINE PRESSURE i CJ UJ J| 2 > "1 1 Si Jf j!* 4 &-S 11 *ij u ;i *. 3 Slflli MAXIMUM CAPACITY OF 100 DIFFERENTIAL GAUGE CUBIC FT. PER HOUR Jo oooo o ooooo oooog Sogoo ,ooS ggggg ggggg gSSSS gSSSS g gggSS Sgggg ggggg ) 000 00000 O 00000 00000 00 000 O 0000 O O OOO 00000 ,000 ~10 u, ou.0,5000002,.,5.20 oujo.no ooooo ~lo I1II IIHi IH MAXIMUM CAPACITY OF 50 DIFFERENTIAL GAUGE DIAMETERS OF ORIFICES -INCHES 217 MEASUREMENT OF GAS AND AIR Fig. 8320 INCH DIFFERENTIAL GAUGE 218 MEASUREMENT OF GAS AND AIR MEASURING GAS IN LARGE VOLUMES* "The following information was compiled from records obtained under ordinary operating conditions. Data obtained at the city gates of Lawrence, Kansas, where the Kansas Natural Gas Company maintains two orifice meter settings one in a 6 inch line and the other in an 8 inch line: After the gas passes through the orifice meters it is again measured through a 100,000 cu. ft. per hour Thomas electric meter and, covering a period of 444 days, there was 342,156,000 cu. ft. registered through the orifice meters, 343,108,000 cu. ft. registered through the Thomas electric meter, a difference of 952,000 cu. ft., or a difference in percentage of 0.28 (twenty-eight one-hundredths of one per cent). Data which was obtained at the city gates of Leaven- worth, Kansas, where the Kansas Natural Gas Company maintains a 10 inch orifice meter setting: After the gas passes through the orifice meter it is then measured through a 100,000 cu. ft. per hour Thomas electric meter and, cover- ing a period of 252 days, there was 186,251,000 cu. ft. regis- tered through the orifice meter, and 185,969,000 cu. ft. registered through the Thomas electric meter, a difference of 282,000 cu. ft. or a difference in percentage of 0.15 (fifteen one-hundredths of one per cent). Comparative runs under ordinary operating conditions, at a 4 inch orifice meter setting measuring gas to an isolated portion of the Wyandotte County Gas Company's distri- bution system in Rosedale, Kansas, supplying about two hundred domestic consumers : -After the gas passed through the orifice meter it was again measured through three 60-A tin meters (1800 cu. ft. per hour each) and, covering a period of 120 days, there was registered by the orifice meter 4,553,- 840 cu. ft., and through the three 60-A tin meters 4,480,380 cu. ft., a difference of 73,460 cu. ft., or a difference in per- * By V. C. Jarboe 219 MEASUREMENT OF GAS AND AIR centage of 1.61 (one and sixty-one one-hundredths percent). The differential carried on this orifice meter varied from 2 inches at night to about 48 inches during the peak, or meal- time load. Taking into consideration the figures closed as of Feb- ruary 25th, 1922, at the city gates of Lawrence, Kansas, covering a period of 750 days, the orifice meters registered 547,759,000 cu. ft., the Thomas meter 548,417,000 cu. ft., a difference of 658,000 cu. ft. or a difference in percentage of 0.12 (twelve one-hundredths of one per cent). The figures closed as of February 25th, 1922, at the city gates of Leavenworth, Kansas, covering a period of 527 days, the orifice meter registered 357,978,000 cu. ft., the Thomas meter 357,961,000 cu. ft., a difference of 17,000 cu. ft. During all of this operation the meters were given the ordinary attention that meters should be given in order to get dependable measurements. The Thomas meters referred to above are the property of the Lawrence and Leavenworth Gas Companies, and the three 60-A tin meters are the property of the Wyandotte County Gas Company." 10A.M. Fig. 8J SECTION OF 10 INCH, 10 LB. ORIFICE METER CHART 220 MEASUREMENT OF GAS AND AIR EFFECT OF ATMOSPHERIC PRESSURE ON GAS MEASUREMENT The volume of gas measured is expressed at a certain pressure base, which is usually designated as a certain number of ounces or pounds per square inch. This pressure is the gauge pressure above the atmospheric pressure at the point of measurement unless otherwise designated by contract or common understanding. The standard practice has been to consider atmospheric pressure as 14.4 Ib. per square inch. While it is true that this value is a representative one for most of the gas fields, gas is being produced in large volumes in locations of high altitude where the pressure of the atmosphere is 11.9 pounds per square inch and even less. Where the atmospheric pressure is 14.4 Ib. per square inch and gas is measured at an 8 ounce base, the total or absolute pressure base in pounds per square inch, is 14.4 Ib. plus 8 ounces (0.5 Ib.) or 14.9 Ib. per square inch. However, at 11.9 Ib. atmospheric pressure, the same 8 ounce pressure base represents an absolute pressure of 11.9 Ib. plus 8 ounces (0.5 Ib.) or 12.4 Ib. per square inch, s,o that with temperature conditions similar, the weight of gas in a cubic foot in the first instance is approximately 20 per cent greater than in the second. If the gas being produced at the higher altitude were piped to a lower altitude, the calculated volume decreases if the same pressure base is used for measurement above the atmospheric pressure at each point. Using the two values above cited, 600,000 cu. ft. measured at 8 oz. above 11.9 Ib. atmospheric pressure would become only 500,000 cu. ft. at the 14.4 Ib. pressure at an 8 ounce base. The weight does not change neither does the heat content. The value of gas consists mainly of its heat producing quality. Although it is not purchased or sold on this basis directly, this condition is approached in high pressure meas- 221 MEASUREMENT OF GAS AND AIR Fig. 85 ORIFICE METER INSTALLATION, FLANGE TAP CONNECTIONS 222 MEASUREMENT OF GAS AND AIR urement, by contract requirements of a certain pressure base and base temperature at which the volume shall be calculated. If all gas had the same specific gravity the above method of measurement would insure the same weight of gas in each cubic foot. However, the heat content varies with the chemical constituents of the gas, so that the only manner in which gas could be sold on a heat or B. t. u. basis would be to have a combustion analysis made. Such an analysis is not usually made but for practical purposes gas and fuel oil are used under the same or similar boilers at the same load to determine the relative economy of the two fuels. A barrel of fuel oil will weigh nearly the same regardless of atmospheric pressure so that in comparing fuel oil with gas it is necessary to know the absolute pressure under which the gas volume is expressed. If the gas measured at 8 ounces above a atmosphere of 11.9 Ib. or 12.4 Ib. per square inch absolute contained 800 B. t. u. per cubic foot, the same gas measured at 8 ounces above 14.4 or 14.9 Ib. absolute would contain 960 B. t. u. per cubic foot. Assuming the barrel of fuel oil contained 4,800,000 B. t. u. it would be equivalent to 6,000 cu. ft. measured at 12.4 Ib. absolute and 5,000 cu. ft. measured at 14.9 absolute. So that in making comparisons, the atmospheric pressure may become an im- portant factor. The above examples illustrate what an important part atmospheric pressure plays in gas measurement at high altitudes. For purposes of comparison gas must be calculated on the same absolute pressure base. The Department of In- terior have issued regulations in regard to this subject in "Regulations to Govern the Production of Oil and Gas,"* which provides that all gas must be reported on a base of 10 oz. above an atmospheric pressure of 14.4 Ib. per sq. in. or 15.025 Ib. absolute. The effect of the atmospheric pres- * See Page 232 223 MEASUREMENT OF GAS AND AIR sure on the absolute pressure base only affects the value of the Coefficient. If the atmospheric pressure varies from 14.4 and it is desired to measure the gas at a certain number of ounces or pounds above the atmosphere, the Coefficient must be revised if it was derived by using 14.4 as the at- mospheric pressure, for the Coefficient C is equal to : Where P& is the pressure base in pounds per square inch absolute. It is readily seen that as P b decreases in value; C increases, and consequently the calculated volume in- creases. The formula for revision of the Coefficient is given on Page 189 and Table of Multipliers on Page 196. When it is desired to measure gas at a pressure base above a pressure of 14.4 so that the volume would be equal to that which would occur if the pressure were 14.4 regardless of the atmospheric pressure at point of measurement, then the Coefficient should not be revised, on account of the different atmospheric pressure, if the Coefficient was derived by using 14.4. The reader is referred to Contracts, Page 230, for in- terpretations of various phrases regarding pressure base and atmospheric pressure. In addition to the effect on the basis of measurement, the pressure of the atmosphere also affects the quantity due to the absolute pressure of the gas being measured. The quantity of gas when measured by an orifice meter is where Q = quantity in cubic feet per hour passing the orifice. C = Hourly Orifice Coefficient of the orifice. The value of this term is affected by the pressure base and any factor which affects the value of the pressure base in absolute units. h = differential in inches of water. 224 MEASUREMENT OF GAS AND AIR P =f Static or line pressure expressed in pounds per square inch absolute which is the atmospheric pressure plus or minus the gauge pressure.* The static pressure or line pressure in pounds per square inch or in inches of mercury vacuum is usually recorded on the same chart as the differential pressure. When orifice meters were first commercially used, the average atmospheric pressure of all the gas fields was 14.4 Ib. and this value was used and is still used in the preparation of tables of Pressure Extensions, which tables give the values of ^IhP for various values of differential in combination with various pressures. In these tables P is equal to 14.4 plus the gauge pressure, and in cases of vacuum lines, P equals 14.4 minus .4908 times inches of mercury vacuum. 14.4 Ib. is considered the atmospheric pressure. It is readily understood that if the atmospheric pressure varies from 14.4, the volume will be affected. For example, if the gas is flowing under an atmospheric pressure of 11.9 or 2.5 Ib. below 14.4 and the static pen rested at zero without any previous adjustment, the pressure on the gas would be equivalent to a minus pressure or 5 inches vacuum below an absolute pressure of 14.4 Ib. If the tables of Pressure Extensions are used without any adjustment for change of atmospheric pressure the error in this case is V(14.4+0)& compared with V(11.9+0)& or 3.795/z compared with 3.456/z, being 10 per cent error. At 125 Ib. the error is about 1 per cent V(14.4+125)A=11.81A, and V(11.9+125)A=11.70&. At 500 Ib. the error is one- fourth per cent. However, under a vacuum the error in- creases as the vacuum increases. At 20 inches of mercury vacuum the error is 46 per cent. V(14.4 -.4908 X 20) h = 2.\4h V(l 1.9 .4908X20) A = 1 .46 A * See Page 169. 225 MEASUREMENT OF GAS AND AIR The book of Pressure Extensions may be used by making adjustments either to the readings or to the static gauge. When the atmospheric pressure is less than 14.4 make a deduction from the static reading equal to the amount that the atmospheric pressure is less than 14.4. For example, where the atmospheric pressure is 2.5 Ib. less than 14.4 or 11.9 Ib. subtract 2.5 Ib. from all gauge readings. When the gauge reading for a period is 20.5 Ib. and differential is 30 inches, look up the extension of 20.5 2.5 Ib. or 18 Ib., and 30 inches differential. This method may be proved thus : V(11.9+20.5)30= V(14.4+18)30 V32.4X30 = V32.4X30 In cases of vacuum, add numerically to the gauge reading in inches of mercury, the difference between 29.3 inches mer- cury (14.4 Ib.) and the barometric reading. If the baromet- ric reading is 24.3 inches (11.9 Ib.) the difference is 5 inches, then if the static reading is 20 inches and the differential is 10 inches, to obtain proper volume for the period look up the extension of 20 plus 5 or 25 inches of mercury vacuum and 10 inches differential. For V(l 1.9 -.4908X20) 10= V (14.4 -.4908X25) 10 V(H.9-9.8)10= V(14.4-12.3)10 V2.1X10 = V2.1X10 Adjustments may be made on the gauge to save all office work. When the atmospheric pressure is less than 14.4, install the recording differential and static gauge with the static pen located a space below the zero line equal to the number of pounds that the pressure of the atmosphere is less than 14.4. Thus, when the atmospheric pressure is 11.9 set the static pen 2.5 Ib. below zero when the gauge is open to 226 MEASUREMENT OF GAS AND AIR the air. When a pressure acts on the gauge and the gauge registers 0, the absolute pressure will be 11.9+2.5 or 14.4 which corresponds to the absolute pressure for Ib. in the pressure extension tables. Where the reading is 10 Ib. the absolute pressure registered by the pen is 12.5+11.9 = 24.4 Ib. per square inch absolute, which is the absolute pressure corresponding to 10 Ib. in the Pressure Extension Book. Gauges on vacuum lines are adjusted in a similar manner. If the barometer reading is 24.3 inches (11.9 Ib.) which is 5 inches of mercury less than 29.3 inches (14.4 Ib.) set the pen at 5 inches of mercury vacuum (below the zero line) when the gauge is installed or when open to the atmosphere. When the chart reading is 20 inches of vacuum the pressure is 15 inches below the atmosphere (24.3 less 15) or 9.3 inches absolute which is the same absolute pressure used in cal- culating the pressure extension (29.3 20 = 9.3) except that this value is expressed in pounds in making the calculations. When the atmospheric pressure is greater than 14.4 adjust- ments are made in the opposite manner. For instance if the atmospheric pressure is 14.7 Ib. add 0.3 Ib. to the static pressure readings before looking up the extensions. If on a vacuum line subtract 0.6 inches of mercury from the gauge reading before obtaining the extension. If it is desired to have the change made by the gauge so as to use the Pressure Extension Tables without any further trouble set the static pen to read 0.3 Ib. or 0.6 inches of mercury above the zero when the gauge is open to the atmosphere. Do not make revisions to both the readings and the gauge but only to the one or the other. When adjustments are made notations should be shown on charts and reports so that checkers may be able to make calculations in proper manner. From the preceding discussion it will be noted that the effect of the atmospheric pressure on the pressure base, creates a constant percentage deviation on the quantity 227 MEASUREMENT OF GAS AND AIR and the effect on the static pressure is variable. The follow- ing examples indicate the varying results which may be ob- tained from the same data. Gas being measured with pressure connections at 2J4 and 8 diameters from the orifice. Period one day. Size of line, 8 inches. Diameter of Orifice, 6 inches. Pressure Base, 4 oz. Specific Gravity, .600. Atmospheric Pressure 12.4 Ib. Temperature 60 deg. fahr. Unrevised Hourly Coefficient is 16664, see Page 175. Average Gauge Pressure 10 Ib. Average Differential Pressure 16 inches. Gauge not adjusted. (1) Coefficient revised, Pressure Extensions not revised. (14 4-1- 25) * = 24X16664)- ' V (14.4 + 10) 16 = 9,152,000 cu. \LZA-\-.Zo) . j it. per day. (2) Coefficient and Pressure Extension revised. (14.4 + .25)* Q = 24X16664 ~ V (14.4+8)16 = 8,768,000 cu. ft. per day. (3) Coefficient not revised, Pressure Extension not revised. (2 = 24X16664 V(14.4+ 10) 16 = 7,927,000 cu. ft. per day. (4) Coefficient not revised. Pressure Extension revised. <3 = 24X16664 V (14.4+8) 16 = 7,572,000 cu. ft. per day. Whether method (2) or (4) should be applied depends upon the contract. * See Page 189 for revision of coefficient for change of atmospheric pressure. 228 MEASUREMENT OF GAS AND AIR Fig. 86 ORIFICE, FLANGES AND 50 INCH DIFFERENTIAL GAUGE INSTALLATION. PIPE TAP CONNECTIONS. NOTE BY-PASS BETWEEN GAUGE LINES 229 MEASUREMENT OF GAS AND AIR GAS CONTRACTS All true contracts begin with an agreement. By agree- ment is meant the meeting of the minds of the contracting parties in a common assent to the same definite conclusion. In order that the agreement may cover completely all points over which doubt may arise it should be drawn up as complete as possible. The following are specimen clauses which appear in gas leases regarding the methods of measurement of gas: "All meters necessary for the Measurement of Gas under this contract shall be furnished by the buyer and shall be either or at the option of the buyer and gas measurement by same shall be corrected to a basis of oz. pressure. It is agreed that should the meter, for any reason, fail to work and fail to register the amount of gas to the buyer, then the amount to be paid by the buyer during such time as the meters shall fail to register, shall be the average per day for the last preceding calendar month for which an accurate meter reading was had, multiplied by the number of days during which the meter failed to register. In case any question arises as to the accuracy of the meter measurement at any time, the meter shall be tested by either party, and the party demanding the test shall pay the ex- pense of such test. No corrections for meter measurements are to be made dating back to the last test prior to date of complaint." "The buyer shall at his own expense install and keep in repair meters of standard type sufficient in size to measure the number of cubic feet of gas received by him under this agreement, together with said meters to be installed on the above described property. The said meters shall be read daily in accordance with rules, methods and instructions of the Metric Metal Works or other standard forms for correct reading of such meters and the amount of gas so metered shall be computed on the basis of ounces to 230 MEASUREMENT OF GAS AND AIR a square inch above atmosphere. The seller shall have at all times, the right to inspect such meters providing, however, the buyer shall be notified in time to be present when such test is made, if he so desires. And it is agreed that if, after such examination it shall be found that the meter or meters are correctly measuring or registering the said gas, then the expense of such examination and test shall be borne by the seller, but if it shall be found, after such examination, that the said meter or meters are in bad repair, or do not correctly measure or register the gas, then the party of the second part shall correct same at his own expense and pay expense of such examination." Other contracts have been prepared which read as follows : "The meters to be used in the Measurement of Gas shall be Orifice Meters and furnished by the buyer, and the amount of gas measured shall be reduced by calculations to oz. pressure above an assumed atmospheric pressure of 14.4 and the volume shall be expressed at a temperature of 60 deg. fahr." Inasmuch as a contract is legally assumed to be a meeting of the minds of the parties making the contract, it is very essential that the contract shall contain sufficient data or description to eliminate a different interpretation or con- struction being placed upon the words by either of the parties. On Pages 221 to 228 the subject of atmospheric pressure is explained in detail, and on Page 171 the minor deviations due to standard values used in the computation of formulas etc., are mentioned. In order that the parties of the contract shall have full knowledge of the basis of measurement, it is recommended that the subject of the Table of Hourly Orifice Coefficients to be used should be incorporated as well as a more definite phraseology regarding pressure base on which the gas shall be calculated, especially in those fields where the average atmospheric pressure varies appreciably below, or above 14.4 Ib. per square inch. 231 MEASUREMENT OF GAS AND AIR On Pages 221 to 228 it is noted that the difference of at- mospheric pressure produces a considerable effect upon the basis of measurement or upon the value of the coefficient used when different interpretations are placed upon the term "atmospheric pressure." In order that the same quantity of gas shall constitute a cubic foot as far as is practically possible, (which would exactly constitute the same cubic foot at all places) the use of absolute atmospheric pressure is recommended, an expression of a certain number of ounces above an assumed atmospheric pressure of 14.4. A cubic foot of gas at 10 oz. above the assumed atmospheric pressure of 14.4 or an absolute pressure of 15.025 pounds would con- tain exactly the same weight of gas at any place providing the chemical constituents of the gas were the same. The Bureau of Mines has issued definite instruction in regard to pressure base and temperature base as follows. ARTICLE 15* REVISED MAY 31, 1921. "All gas subject to royalty shall be measured by meters approved by the supervisor and installed at the expense of the lessee at such places as may be determined by the super- visor or his deputy. The standard of pressure in all measure- ments of gas sold or subject to royalty shall be 10 ounces above an atmospheric pressure of 14.4 pounds per square inch regardless of the atmospheric pressure at the point of meas- urement, and the standard of temperature shall be 60 deg. fahr. and all measurements of gas shall be reduced by com- putation to these standards no matter what may have been the pressure and temperature at which the gas was actually measured." It is noted on Page 224 that if this is the intention of the party entering the agreement to use a base above an assumed pressure of 14.4 lb., no revision is required for the Coefficients. * Plan for Conducting Work under Operating Regulations to Govern the Pro- duction of Oil and Gas. Under the Act of February 25, 1920. 232 MEASUREMENT OF GAS AND AIR During the past few years some companies have made their own orifice discs or have had them made at a nearby machine shop and have calculated Coefficients for the discs from data given in books of reference. In addition, many companies have prepared tables of Orifice Coefficients based upon an average mean curve of values of the "coefficient of velocity" which Coefficients deviate from those which have been published by the various manufacturers. For example, the Tables of Coefficients for 2J/2 diameters upstream and 8 diameters downstream, as published in this book, were com- puted from a mean curve drawn through the plotted values of the coefficient of velocity as determined by experiment. This curve was plotted on a very large scale and the values of the coefficient of velocity were obtained from the curve by inspection. After several years work a formula was de- rived for a curve by using four points on the plotted curve, which very closely approximated the original curve. However, in some places the curve of the formula deviates from the plotted curve by approximately one-tenth of one per cent and therefore any Coefficients obtained by use of the formula will differ by one-tenth of one per cent from the Coefficients derived from the plotted curve. Even though the matter of even one-quarter of a per cent has no appreciable effect upon the price per thousand cubic feet of gas in preparing the contract, the mention of a certain published Table of Coefficients or a statement of the Coefficients to be used, incorporated as a part of the contract would eliminate the dis- cussion or friction between the chart reading departments of the parties to the contract. It is obvious that, if one party was using a Table in which the Hourly Orifice Coefficient for a 4 x 2 orifice at 4 oz. pressure base, atmospheric pressure 14.4, base and flowing temperature 60 deg. fahr., specific gravity .6, was 2,019.4 and the other party used a Table where the Co- efficient for the same orifice under the same conditions was 2,014.0 that there would be a difference at the rate of five 233 MEASUREMENT OF GAS AND AIR 234 MEASUREMENT OF GAS AND AIR dollars for each $2000 worth of gas sold. It is also perfectly obvious that if the gas is being sold at 40 cents per thousand, the acceptance or rejection of the contract would never hinge on whether the rate should be 40 or 40.1 cents per thousand. However, after contracts have been made these variations in tables have been brought up by parties interested with consequent friction. The incorporation of either a ref- erence to the Table to be used or the publication of a Table as a part of the contract w r ould eliminate most of the friction which now exists relative to the use of Coefficients and methods of determination of volumes. A clause of which the following is an example could be used. "All meters necessary for measurement of gas under this contract shall be furnished by the buyer and shall be orifice meters. The gas measurement determined by same shall be revised to a pressure base of 8 oz. above an assumed atmospheric pressure of 14.4 Ib. per square inch (absolute pressure 14.9 Ib. per square inch). The basis of temperature for measurement shall be 60 deg. fahr. The values of the Coefficients used for orifices shall be those contained on Page ... of the book "Measurement of Gases and Liquids by Orifice Meter," published by the Metric Metal Works. The Coefficient shall be revised for changes in specific gravity of gas using multipliers in Table ... in book above referred to. The specific gravity shall be determined by the method monthly or about the 25th of the month. Repre- sentatives of both parties shall be present at the test and their decision shall be the basis for calculation for the fol- lowing month .revision to the Coefficient used shall be made on account of flowing temperature. The average temperature for each week shall be obtained by a recording thermometer. In case that there is no revision to the coefficient the word "no" is inserted and the second sentence relative to method obtaining temperature is omitted. 235 MEASUREMENT OF GAS AND AIR In the example given above the reference to this Hand Book may be replaced by reference to other published tables, or tables prepared and made a part of a contract. An additional phrase in regard to Coefficients for various sizes of orifices not given in the above Tables, follows: Coefficients for orifices not given in the above Table shall be calculated from the formulae given on Page . . . from the book "Measurement of Gases and Liquids by Orifice Meter," and such values shall be used only after agreement by both parties. MULTIPLE ORIFICE METER INSTALLATION In cases where the flow of gas varies over very wide limits it may become necessary to install meters on parallel lines to accurately measure the minimum rate of flow. Fig. 88 shows a layout for this purpose. When the rate of flow is small, the Regulator or Differential Gas Relief Valve prevents the gas from flowing through the secondary meter and thus all of the gas passes through and is measured by the primary meter. As the rate of flow through the primary meter increases, the differential pressure increases. When the differential pressure reaches a certain pre-deter- mined amount which is slightly less than the maximum range of the primary differential gauge, the differential pres- sure which also acts on the regulator, causes the regulator to open the valve quickly and permit the increased quantity of gas to flow through both lines and be measured by two meters, both meters being in operation when larger quantities of gas are flowing. When the gas volume decreases the differential pressure at each orifice meter decreases and when it has reached a certain minimum which is insufficient to create a fair differential reading on both of the charts the Differential Relief Valve closes and causes all of the gas to pass through the primary meter, 236 MEASUREMENT OF GAS AND AIR 8 237 MEASUREMENT OF GAS AND AIR Fig. 89 238 MEASUREMENT OF GAS AND AIR INSTALLING GAS OR AIR METERS The location of taps in the main line, for pressure con- nections between the pipe line and the Differential Gauge are dependent upon the Hourly Orifice Coefficients which are used, and vice versa. Connections 2^ diameters upstream and 8 diameters downstream from the orifice are Full Flow Connections. The stream flow occupies the full section of the pipe at the taps and is not restricted in area which is the case for all points closer to the orifice. See Fig. 90. Flange Connections are also used for gas, air, and water measurement. MM- Orifice/ Fig. 90 FULL FLOW CONNECTIONS Fig. 91 FLANGE CONNECTIONS SKETCHES OF ORIFICE METER INSTALLATIONS. CURVED LINES ARE LINES OF STREAM FLOW When Full Flow Connections are used as in Fig. 90, the static pressure recorded at G is the pressure at U. For Flange Connections the line pressure at D is recorded on the chart, See Fig. 91. When Gauges are received with the Static Pressure Spring connected with the upstream pressure portion of the Differential Gauge, no change is required when used with Full Flow Connections. However, when Flange Connections are used the Static Pressure Spring must be connected to the downstream portion of the Differential Gauge. In this case remove the stuffing box at M (at the end of the flexible steel tubing) from the high pressure side of the gauge and attach it to the low pressure portion at tap F. The tubing is flexible and may be bent in any position. 239 MEASUREMENT OF GAS AND AIR 240 MEASUREMENT OF GAS AND AIR Orifice Meter Installation For Measuring Gases Install the meter as far as possible from compressors, pumps or regulators. It is impossible to accurately measure any gas or liquid subject to violent pulsation. The installation should be made with a level section of pipe on each side of the orifice, using a straight run of pipe of the same diameter without any fittings of any description within a distance of 16 diameters of pipe in either direction from the orifice. When installing in a gas line place one gate valve at a distance of 16 diameters or greater upstream from the orifice and another gate valve at the same distance downstream. Gas must be dry to obtain proper measurement. Use drips at all low points in the line to remove condensates. Fig. 93 AN INSTALLATION USED IN THE OS AGE INDIAN RESERVATION. SEE PAGE 164 The minimum distances of 16 diameters mentioned, apply for all locations where it is possible to obtain this dis- tance on each side of the orifice without any valves or elbows. Distances less than these have been used satisfactorily and it is quite possible to reduce this distance, although no de- finite rule can be given as to the effect that different com- binations of fittings at each location will produce. It is possible to test out orifice installations in which shorter lengths of straight pipe have been used on each side 241 MEASUREMENT OF GAS AND AIR of the orifice. This is accomplished by drilling 3 one-quarter inch holes in the pipe at 2J^ diameters upstream, one hole in the top of the pipe and one on each side of the pipe where the upstream section is less than 16 diameters in length. In case the downstream section is less than 16 diameters in length, the three holes should be drilled at 8 diameters from the orifice, one on top and one on each side of the pipe. If the stream line flow through the orifice converges and di- verges uniformly, the pressure at any two of the three taps upstream or downstream should be the same. If there is any appreciable difference in the pressures at either set of taps it is evident that the stream line flow is not concentric with the pipe. In order to make a simple test, connect one column of a U tube to the tap in top of the pipe, and the other column to one of the taps in the side of the pipe. When the normal rate of flow exists through the orifice, the difference in the heads of the water in the two columns of the U tube should not be more than one-quarter of an inch. If more than this, it is evident that the flow of the gas is influenced by some condition other than the orifice. The stream line flow through the orifice will be the same irrespective of where the pressure taps are made. It does not make any difference whether they are made at the pipe connections, at the flanges or at other intermediate points. Any condition which will affect the stream line flow other than the orifice will affect the differential readings. A by-pass for the main line should be installed, connecting the main line ahead of the inlet valve and the main line beyond the outlet valve, around the meter layout. The size of pipe for the by-pass should be one half of the diameter of the main or greater and contain one valve, or two valves with a sleeve between them. In the latter case when the valves are closed the sleeve can be left open and thus prevent the flow of any gas through the by-pass. 242 MEASUREMENT OF GAS AND AIR 243 MEASUREMENT OF GAS AND AIR 214 MEASUREMENT OF GAS AND AIR Orifice Meter Body Set the meter level in the line with the inlet and outlet lines connected to the correct end of the meter casting. Leave space under the body so that the drain plug can be removed whenever desired. Use oil on the thread of the orifice disc before screwing into place. Screw disc tight but without using force. Orifice Meter Flanges Set up the Flanges so that the jack screws are level with each other. Flanges tapped for pressure connections should be set with the taps vertical. Place orifice disc with bevelled edge downstream. Use a gasket on each side of the orifice disc. These gaskets should contain openings as large as the pipe and should be shellaced on the pipe flanges. Do not use shellac on the face of the gaskets next to the orifice plate, white lead is preferable. Gauge Line Connections or Taps For Full Flow or Pipe Connections (2}/2 Diameters Upstream and 8 Diameters Downstream) . See Pages 251 to 254. Tap the pipe line at U, 2J/ diameters upstream, and at D 8 diameters downstream from the orifice for J^ inch pipe connections to the differential gauge. Larger connections may be used. Tap above the center of the pipe, so that any condensate accumulating in the connections will drain into the main. The openings must be tapped clean and perpendicular to the pipe line. After the nipples have been screwed in, examine the interior of the pipe to be sure that there are no burrs or that the nipple does not extend into the pipe. All burrs, chips, etc., should be removed. The inside of the pipe should have a smooth surface at the tap, otherwise the dif- ferential reading may be affected. 245 MEASUREMENT OF GAS AND AIR Instead of making taps in the pipe line for the connections if possible weld a short length of J4 i ncn pipe to the main at points U and D then drill the pipe with a small drill pass- ing through the nipple. This will avoid the possibility of any large projections in the pipe. Taps 1}/2 diameters upstream and 8 diameters downstream from the face of the orifice, are 10 inches upstream and 32 inches downstream for a 4 inch pipe. Screw two J4 inch pipe plugs in taps in flanges, if flanges contain taps. Gauge Line Connections or Taps For Flange Connections See Pages 252 to 254. Flanges furnished for Orifice Meters contain holes tapped for }^ inch pipe. Hourly Orifice Coefficients for Flange Connections are not the same as for Full Flow Connections (2J^ diameters upstream and 8 diameters downstream). Orifice Meter for Coke Oven Gas In an installation for measuring Coke Oven Gas, place the orifice disc (with the small hole in the disc below the orifice) between Steam Jacketed Flanges, so that the meter can be kept heated. Any tar which is deposited on the orifice plate will be kept in a fluid state and will run off, leaving a thin skim which will prevent the orifice plate from being oxidized by the action of the ammonium sulphates contained in the gas. The tar, which is deposited on the up- stream side of the orifice, is drained, by the small opening in the orifice plate, into the downstream side, where it may be drained off by a drip placed in the line. The tar will form a seal for the small hole in the plate. All other instructions are identical with those for measuring gas. 246 MEASUREMENT OF GAS AND AIR INSTALLING THE RECORDING DIFFERENTIAL AND STATIC PRESSURE GAUGE For Measuring Gas or Air 100 inch Gauge and Orifice Meter Body. Page 251. 50 inch Gauge and Orifice Meter Body. Page 251. 50 inch Gauge, Full Flow Connections. Page 252. 50 inch Gauge, Flange Connections. Page 252. 10 inch or 20 inch Gauge, Full Flow Connections. Page 253. 10 inch or 20 inch Gauge, Flange Connections. Page 253. 50 inch or 100 inch Gauge, Full Flow Connections. Page 254. 50 inch or 100 inch Gauge, Flange Connections. Page 254. These instructions apply to any of the diagrams above mentioned. See Pages 251 to 254. Setting up Gauge Install the gauge on a 2 inch pipe support, attached to the line or on a solid foundation. It may be attached directly to a solid post or placed on a shelf. The gauge must be set level and rigid so that it will not be affected by any excessive vibration. Differential Pen Arm Remove the plate (on which the number plate is fastened) and attach the differential pen arm in accordance with the instructions pasted on face of chart. Glass Remove the glass face from box of charts and attach to frame underneath the wire clips. Adding Mercury Remove the plug with rod from the funnel in the top casting and pour in the mercury, which is shipped in a pipe container. The plug with the rod attached is used only in shipping the gauge. Add mercury until the differential pen rests at zero. The float should rise about one-eighth inch above the bot- tom of the low pressure chamber. When the pen rests at zero insert a small rod through the funnel opening, touch the float and be sure that it is floating and not resting on the bottom of the chamber. The funnel is closed with the one-eighth inch plug shipped with the gauge. 247 MEASUREMENT OF GAS AND AIR Static Pressure Connections On account of the vari- able conditions under which meters and gauges are in- stalled, it is impossible to present layouts which will meet all requirements. However, the instructions and layouts in- dicating the relative location of test connections V and P, and valves should be strictly followed. Connect the tap in gauge at H with the tap U in the line, and tap L in the gauge with tap D in the line, with % inch pipe. Larger pipe and fittings may be used. Insert valves in the connecting lines just above the taps in the main with unions above the valves. Drips may be installed in gauge lines for the purpose of collecting moisture and acting as partial shock absorbers. They are generally omitted. Always give the lines a slight slant from the gauge toward the main and avoid any traps. Place valves and fittings in the same relation to each other as shown in diagram. Supplementary valves W and X may be placed near the gauge if the gauge is located some distance from the line. Place them between the pipe line taps U and D, and the test or by-pass connections, never between the gauge and any test or by-pass connection. By-Pass It is desirable to install a by-pass as shown, placing valves at Y and Z and plug or valve at K. Removing Chart To remove the chart, raise the pens from chart with the pen lifter and remove the knurled thumb-nut in the center. The metallic dial can be taken off by twisting it slightly to the left after the four holding screws have been loosened. (Do not take them out). Clock The clock should be wound with the key furnished with the instrument. The movement is carefully timed before leaving the factory; however, if it should be necessary to regulate it, remove the dial and cover of clock box, and shift the small regulating lever in the proper di- rection. Clock movements are usually wound each day but will run for two days. 248 MEASUREMENT OF GAS AND AIR Placing Chart Keep the pens from resting on dial by means of pen lifter and slip on a chart without touching the pens. Set the chart so that the pens will point to the particular hour of the day desired and secure in place with the knurled thumb-nut. Pens and Ink Fill the V shaped pens with ink using the ink dropper. Do not fill the pen more than two- thirds full and see that the ink flows when the pen touches the chart. Use black* ink in the lower or static pressure marking pen and red ink in the upper or differential pressure marking pen. Use the special ink only. Clean the pens frequently using a moistened edge or piece of blotting paper. To protect the pens the chart should be kept on the instru- ment whether in operation or not. Pens should rest at zero before turning gas or air into the meter and gauge. Be sure that the pen bears lightly on the chart, enough to make a clear line, but not so hard as to impair its sensitiveness. Do not bend the pens up or down but let them incline as received if they follow the arc. The ink will rise, due to capillary attraction. Turning on Gas or Air. Close K Open Y and Z Then open W and X After the pressure is equalized in both portions of the gauge Close Y and Z OpenK Leaks Be sure that valves Y and Z do not leak. Test all connections with soap suds and stop all leaks. Look after valve stems especially. Orifice Capacity After gauge is in operation, if the differential pen records near the maximum reading, change the orifice for one of a larger size. If this is not possible and it is found that the flow of gas keeps the marking arm * Blue or green ink may be used. 249 MEASUREMENT OF GAS AND AIR at or above the maximum differential circle, it will be neces- sary to use a larger size of line and orifice flanges or meter casting in order to use a larger size of orifice, or use a dif- ferential gauge with a higher range of differential. If, after twenty-four hours, the differential reading ranges at or below 10 per cent of the maximum range of the chart in inches, change the orifice for one of a smaller size or use a differential gauge with a smaller maximum range. Tem- porarily the gas may show an abnormally high static and differential pressure until the flow becomes settled. For tables of different sizes of orifices required for measur- ing gas and air, see Pages 214 to 217. Vibrating Differential Pen Arm The hole in the bottom of the mercury pot of gauges, Figs. 97, 98, and 99, is % inch in diameter. When the gas measured shows a pulsation which affects the differential pen arm marking on the chart, decrease the size of the opening in the mercury pot by screwing in one of the two bushings shipped with the gauge. For severe vibration use the bushing having a TS inch hole. For slight vibration use the bushing having a J/g inch hole. In testing gauges for accuracy when a small hole bushing is used, allow extra time for the mercury to reach its level before reading chart. The bushing furnished for the U type of gauges is screwed in the upper end of the J/g i ncn pip e where it enters the low pressure chamber. In gauges, Figs. 100 and 109, the vibration is lessened by reducing the opening in the rubber gasket, (which is placed between the bottom casting and the ring forming the division be- tween the high and low mercury chamber), with a small wooden wedge. If the static pressure pen arm vibrates regularly and rapidly install the meter farther from the source of the pulsation. Never partially close the valves W or X when in operation. See Pulsating Flow, Page 143. 250 MEASUREMENT OF GAS AND AIR K -3j/ametcrs Fig. 96 ORIFICE METER BODY AND 50 OR 100 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR Fig. 97 ORIFICE METER BODY AND 50 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR 251 MEASUREMENT OF GAS AND AIR ^Diameters , 9850 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR, FULL FLOW CONNECTIONS Downstream Connection Fig. 9950 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR, FLANGE CONNECTIONS 252 MEASUREMENT OF GAS AND AIR Fig. 10010 OR 20 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR, FULL FLOW CONNECTIONS Upstream Connect tor. '// Dty Fig. 10110 OR 20 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR, FLANGE CONNECTIONS 253 MEASUREMENT OF GAS AND AIR ^Diameters- Fig. 10250 OR 100 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR, FULL FLOW CONNECTIONS Drain Upstream Connection Fig 10350 OR 100 INCH GAUGE INSTALLATION FOR MEASURING GAS OR AIR, FLANGE CONNECTIONS 254 MEASUREMENT OF GAS AND AIR TESTING DIFFERENTIAL GAUGES For Measuring Gas or Air Gauges should be checked daily or weekly by turning off the gas to see if the marking arms rest at zero. Checking Gauge for Zero: Close K Open Y and Z Close W and X The differential pen arm should return to zero. Open K slowly and allow the gas or air to escape slowly into the atmosphere, thus making sure that there is no pres- sure on either portion of the gauge. The static pressure pen arm should return to zero. There will be a slight difference between the zero position of the differential pen arm when the gauge is under pressure and not under pressure. This difference is created by the expansion of the metal under pressure. The arm should be checked for zero under working pressure conditions. The difference between the zero position under working pressure and not under pressure should be noted and this constant difference should be maintained when checked with the test gauge. The differential pen arm should be kept in practically a straight line at the flexible joint. The differential pen arm can be adjusted to zero by a small movement of the pen arm at the flexible joint, or at the connection with the shaft. When the pen rests at zero determine if the float is floating and not resting on the bottom of the mercury pot. Partially close Y Open X carefully when the differential pen should recede one-fourth inch or more (actual measurement) below the zero line. If the float rests on the zero bottom of the chamber add mercury. See paragraph Adding Mercury, Page 247. After test close X, open Y. 255 MEASUREMENT OF GAS AND AIR Checking Differential Gauge on Pressure Lines Close K Open Y and Z Close W and X OpenK Remove plugs at P and V Attach test gauge by suitable connections at P Close Y, Be sure Z is open Open valve W slightly when a pressure will be exerted on mercury in the high pressure por- tion of the gauge, and on the test gauge. By partially opening or closing valve Z, the pen arm can be stopped at any point on the chart and checked with the reading on the test gauge. After tests remove the test gauge and replace plugs P and V. Proceed as for Turning on Gas, Page 249.. Checking Differential Gauge on Vacuum Lines Close K Open Y and Z Close W and X OpenK Remove plugs V and P Attach test gauge by suitable connections at V Close Z Be sure Y is open Open valve X slightly, when a vacuum will be formed in the low pressure portion of the gauge also on the test gauge. By partially opening and closing valve Y the pen can be stopped at any point desired and reading checked with the test gauge. After tests remove the test gauge and replace plugs P and V. Proceed as for Turning on Gas, Page 249. 256 MEASUREMENT OF GAS AND AIR 257 MEASUREMENT OF GAS AND AIR Checking Differential Gauge under Working Pres- sure If the glass tubes of the test gauge are of sufficient strength to hold the pressure, and the scale is of equal range with the chart in inches of water, the recording differential gauge may be checked with a test gauge by connecting one column of test gauge with tap at P and the other column with the tap at V. Close K Open Y and Z Then open W and X By partially opening and closing valve Y the reading can be checked with the test gauge. It can be left as a permanent installation for check- ing the recorded differential reading of the pen. Adjustment If the zero position of the differential pen is O. K. and the higher readings of the differential pen on the chart do not check with the test gauge, make ad- justment by increasing the length of the float lever arm when the reading is fast, and decreasing when slow. This is ac- complished by moving the lock nuts NN (shown in Figs. 105 and 106) in the proper direction. Beor/ng Shaft Fig. 105. Fig. 106. Testing Static Spring To test static spring attach the test gauge at G and check the two gauges. The use of an inspector's test gauge is recommended rather than the use of a portable dead weight tester. The inspector's test gauge 258 MEASUREMENT OF GAS AND AIR M O p 1 : : 1 j U H i Cfl W CO O S > O o> N O V PC 3 cS 'h p t I H) p i c CO JJBRA1 NTIAL & H 3 11 o S3 N H w 3 <^ o S H X a> OO 22 32.292 5- 6 A. M. 33 21 31.550 6- 7 A. M. 34 22 32.631 7- 8 A. M. 35 24 34.433 Total Coefficient Delivery . . 808.97 1184.7 .958,387 cu. ft. Fig. 112 265 MEASUREMENT OF GAS AND AIR and 32 Ib. from 10 A. M. to 11 A. M., etc. The average reading for each hour being noted on the chart in the hourly period opposite the static pressure record. The extension obtained from the Table of Pressure Extensions, may be written on the outer margin of the chart as shown in Fig. 111. In case they are compiled on a report as on Page 265, all calculations are made on the report and the extensions are added and multiplied by the Coefficient of the disc which will give the delivery. In case the extensions are written on the outer margin of the chart, they are added on an add- ing machine, the sum is noted on back of the chart, where this sum is multiplied by the Coefficient giving the quantity passing for the day. Where the chart only is used all data is compiled on one record which eliminates the use of other forms and the charts for each meter can be assembled in a large envelope day by day with the extension, Coefficient, and daily quantity being noted on the face of the envelope as is shown in Fig. 114. One envelope is used for a month for each meter or location. To reduce the work involved, some companies average the differential reading for the day and the static reading for the day. The pressure extension is obtained for the aver- age readings and is multiplied by the number of hours for which the average was obtained. This product is then multiplied by the Hourly Orifice Coefficient. The average differential for the chart shown on Page 264 is 23 inches. The average pressure is 35 Ib. The extension of these average values is 33.708, which multiplied by 24 equals the total of the pressure extensions for the day. (24X33.708 = 808.99). It will be noted that this result is slightly greater than that derived by obtaining the extension for each hour and adding. Where the differential and static pressure records do not vary over wide ranges this method will give results which will check very closely with the previous meth- od. However, these results will invariably be higher. 266 MEASUREMENT OF GAS AND AIR In case the differential and static pressures vary over wide ranges, this method is not satisfactory due to the fact that the results will be considerably higher than the true result. For very wide variations the charts should be averaged for fifteen minute periods and extensions for the fifteen minute periods should be made to obtain accurate results. Quite frequently a planimeter and reference chart is used to obtain the average differential reading and average static reading. The results obtained by this method are as ac- curate as those obtained by averaging the differential and static pressure records for the day and then obtaining the average extension, which extension is multiplied by the number of hours for which the average was obtained. This method eliminates the necessity of recording the differential and static pressures on the chart and greatly simplifies the work. It should only be used when the static pressures or differential pressures do not vary over wide limits, as the results in such cases will be greater than the true result. If, for any reason, the meter is out of service for a period during which the gas has been flowing, the average reading for the period prior to shut down and ^iter shut down should be used for the period of the shut down. ORIFICE METER CALCULATOR As has been previously explained, the best method of reading and calculating the charts for the determination of flow, is to obtain the pressure extension for each period and add these pressure extensions together and multiply by the coefficient. It has also been explained that the method of averaging the differential pressure for the day, the static pressure for the day, and using these averages for the cal- culation of the flow, will often produce a considerable error if the static or differential pressures vary over a wide range during the day. The use of the planimeter or averaging instrument is also open to the same objection and does not 267 MEASUREMENT OF GAS AND AIR Co ft. o o , as as b b CO O > q h^ ILCULATOR. NECESSARY. i ft, o 1 MONTH'S REA US METHODS ^s r \ tn t\ ^j o b o s^ i b} a< ft, o K, Ci g 3 Q ^&5 b^^^ ^2 K] > ^ co ft. ^ Cl O b O bJ ^ as^ BH si O .ogS ^g^lco &3 ^ ^ Q i|^l s^= OH ^ Q ^ ^O^"^ MEASUREMENT OF GAS AND AIR in any way increase the accuracy but will produce about the same accuracy. To simplify all work and obtain an instan- taneous value of the flow for each hour, or smaller period if desired, a calculator has been placed on the market. By using this instrument the operator can place the chart in proper position on the instrument and determine the flow for any hour during the day without any calculations whatever. That is: the instrument adds 14.4 to the static reading and multiplies the square root of this value by the square root of the differential by the coefficient of the disc at one setting giving the hourly flow. The operation of the instrument is as follows: The chart is placed on the instrument, the sliding scale is moved so that the value of the coefficient is opposite the indicating mark on the lever, and without any further alteration for each chart the lever is moved until the hair line on the transparent indicator is over the average differential reading. The operator then reads the hourly flow opposite the static pressure on the scale. This hourly flow is registered on an adding machine. The chart is moved one hour ahead, lever moved so that the indicator is over the differential reading for the following hour, he looks opposite the static pressure for that hour on the scale and obtains the reading which is placed on the adding machine. For the third hour, the lever is moved until the indicator is over the differential reading for the third hour and opposite the static pressure, he obtains the reading on the diagram and adds this value on the adding machine, etc. At the end of the 24 hour period the total result is added and the volume per day is read from the adding machine. This eliminates any ex- tended calculations, eliminates the necessity of the operator reading the differential pressure and carrying these readings in his mind and obtaining the extension from an extension book. In fact all laborious work involved in calculating orifice meter charts is eliminated. MEASUREMENT OF GAS AND AIR LOCATION Lyons No. 6. Meter No. 241 Orifice No. Ml 790 T Month March, Internal Diameter of Pipe 4-026" Diameter Orifice 2" Pressures at 2J/2 and 8 Diameter Connections. Atmospheric Pressure 144. Temperature 60 deg. fahr. Pressure Base 10 oz. Coefficient, 1261.3 Specific Gravity . Remarks Gas Tested 3-10- '21. Specific Gravity, 0.68 1261.3 x .9393=1184.7 Revised Coefficient used after 10th. Date Pressure Extension Coeffi- cient Quantity Remarks 1 774.97 1261.3 77^70. 2 752.31 " 948889. 3 736.94 " 929502. 4 715.23 1 * 902120. 5 692.14 " 872996. 6 676.33 " 853055. 7 672.86 " 848678. 8 663.54 ' ' 836923. 9 654-92 " 826051. 10 643.41 " 811533. | 11 632.16 1184.7 748920. 12 681.02 " 806804. ' 13 762.45 " 903274- 14 808.97 " 958387. 15 16 17 18 i 19 20 21 22 23 24 25 26 27 28 29 30 31 Fig. 114 270 PART FIVE MEASUREMENT OF STEAM An orifice meter will measure the flow of any gas, vapor or liquid of fairly uniform gravity at high pressure or under a vacuum. It is especially adaptable for the measurement of steam as the properties peculiar to steam simplify all calculations to a minimum. Being a weight measuring instrument as well as a volume instrument, as will be shown later, it becomes the nearest approach to a perfect flowing fluid weighing machine and steam power recording instru- ment. It automatically weighs the moisture in unsaturated steam and even though the amount of moisture or superheat in the steam is unknown, the power as determined is approxi- mately correct for the reason that the correcting factors are very small for relatively large amounts of moisture and super- heat. The great advantage in using the type of meter which is used for measuring gas is that the operator obtains a defi- nite continuous record of the pressure in the line as well as the flow. Flow meters do not give a pressure record on the same chart, this information must be obtained from an in- dependent pressure gauge. Furthermore, it is the consensus of opinion of engineers that the orifice will give more consistent results than can be obtained by the pitot tube or a modification, and the flow nozzle. The ease of installation of the plain orifice, as compared with the nozzle, has made a distinct appeal to the steam engineer. 271 MEASUREMENT OF STEAM For a description of the orifice meter the reader is referred to Part 3. This Part precedes the following details which apply to steam. The Differential Gauge records on a chart the differential pressure between the pressure connections, and the static pressure at one of the connections. These factors with the area of the orifice enable us to determine the flow from the formula : W = C VT7 Where W^ = the quantity of steam passing the orifice. The result can be expressed in "pounds" or "pounds from and at 212 deg. fahr." C = the Hourly Orifice Coefficient for steam. The value of this term remains the same for each installation and basis of measurement. h = the differential pressure existing between the two pressure connections expressed in inches of water head, this value being recorded graph- ically on the chart of the recording differen- tial gauge. P = the static pressure expressed in absolute units, being equal to the gauge pressure (which is recorded on the chart) plus the atmospheric pressure. The value of the gauge pressure is also recorded on the chart. The value of the Hourly Orifice Coefficient C in the above formula is found on Pages 282 and 287, computed for various diameters of orifice and diameters of pipe, these values having been determined by exhaustive experimental and practical tests in comparison with actual displacement. The extensions of the values of V hP have been compiled and are given in the book entitled "Pressure Extensions" pub- lished by this Company. 272 MEASUREMENT OF STEAM Example One hour reading (weight desired) : Average differential reading h = 25 inches. Diam. of Pipe = 4 inches. Diam. of Orifice = 2 inches. Average Gauge Pressure p = 9Q pounds. Hourly Orifice Coefficient C = 48. 19 for 2 inch orifice in a 4 inch line, (Page 282). Weight per hour, W = 48.19 V 25 X (90 +14. 4) Orifice Pressure = 48.19X51.088 = 2462 pounds. Coefficient. Extension. If the heat content or power is desired (using the same data with feed water temperature at 62 deg. fahr.) the Hourly Orifice Coefficient C is 57.55 for a 2 inch orifice in a 4 inch line, (Table 55, Page 287). Orifice Pressure W = 57.55 V 25 X (90 +14.4) =57.55 X 51.088 Coefficient. Extension. or the power passing through the orifice = 2940 "pounds from and at 212 deg. fahr." per hour. Therefore, the Power flowing in the line is equal to the Coefficient of the Disc multiplied by the Pressure Extension. The relation between the differential pressure and the velocity of the fluid through the orifice is expressed by the formula : v=c v Where V = velocity of flowing fluid in feet per second. g = acceleration due to gravity in feet per sec., per sec. = 32. 16. H = differential expressed in feet head of flowing fluid. The well known formula V = V 2 gH expresses the theo- retical flow eliminating friction and other influences. When applied to actual conditions a multiplier is used to take care of the influences due to contraction of jet, friction, 273 MEASUREMENT OF STEAM etc. This factor C v is commonly known as the "coefficient of velocity." This formula may be applied directly for measurement as in the following example. Atmospheric Pressure 14.7. Line Pressure, 100 Ib. Gauge. Diameter of Orifice, 3 inches. Diameter of Pipe, 6.065 inches. Differential, 2 inches of Mercury. Pressure Con- nections, 2 J/2 and 8 diameters from the orifice, no moisture in the steam. O QQ Ratio of diam. of orifice to diam. of pipe = = .495 6.065 C v for .495 ratio =734. For the measurement of steam, the gauge connections to the gauge are filled with water as in measuring liquids and consequently each inch of mercury differential is offset by an inch of water so that 2 inches of mercury pressure as in- dicated is equal to (2X12.6 = 25.2) 25.2 inches of water differential. As one cubic foot of steam at 100 Ib. gauge pressure 62 35 weighs 0.257 Ib. per cu. ft. one foot head of water equals - 0.257 or 243 feet head of steam and one inch of water equals 20.25 feet of steam head at an absolute pressure of 14.7 Ib. per square inch. Therefore, # = 20.25X25.2 or 510 feet head of steam. Therefore, V = C V V 2g# = .734 V2X32.16X510= 132.9 ft. per second. Area of the orifice = .0491 sq. ft. Page 75. Quantity = areaXvelocity = .049lXl32.9 = 6.53 cu. ft. per second. Weight = volume in cubic feetX weight per cubic foot = 6.53X0.257 = 1.68 Ib. per second = 6050 Ib. per hour. 274 MEASUREMENT OF STEAM In the formula V = C V ^2 gH the differential head is ex- pressed in feet head of flowing fluid. As it is not practical to register this value directly, the differential is recorded on the chart in inches of water pressure. If steam is flowing in a line under a pressure of 100 pounds gauge, the weight of a cubic foot of steam is 0.257 Ib. and as water weighs 62.35 Ib. per cubic foot or 243 times as much, one foot of water pressure is equivalent to 243 feet head of steam at 100 Ib. pressure; one inch of water pressure is equal to one-twelfth of 243 feet or 20.25 feet of steam head and 20 inches of water head would equal 20 times 20.25 feet or 405 feet head of steam at 100 pounds gauge. This relation may be expressed by the following formula: 12 w Where H = differential in feet head of flowing steam. w w = weight of water in pounds per cubic foot = 62.35. h = differential in inches of water pressure. 12 = number of inches in a foot. w = weight of flowing steam in pounds per cu. ft. The above example can be written thus : 62.35X20 H = - =405 feet steam head. 12X0.257 Substituting the value of H in the formula V = C V ^ We obtain 7= C v w h_ (2X32.16X62.35 h - C '\- ^r- or 7=18.2810, " w This expreSvSion forcibly illustrates the fact that the ve- locity depends upon the weight per cubic foot of the fluid. As the weight per cubic foot increases, the velocity decreases when the differential pressure is a constant. 275 MEASUREMENT OF STEAM Or using a plain illustration with the same force applied, a ball containing a cubic foot of lead will move with less speed or velocity than a ball containing the same quantity of wood. The weight of steam passing the orifice per hour is equal to the area of the orifice in square feet multiplied by the velocity in feet per hour multiplied by the weight per cubic foot. This fact may be expressed by the following formula : 0.7854 d 2 QQV 144 Wi = 19.635 Where Wi = actual weight of steam passing the orifice in pounds per hour. 0.7854 f = area of orifice in square feet. 144 d = diameter of orifice in inches. 144 = number of square inches in a square foot. 3600 = seconds in one hour. V = velocity of fluid through orifice in feet per sec. Substituting the value of V where 7=18.281 C, J in the expression, W^ = 19.635 d 2 XVXw Wi = 19.635 (FX 18.281 C, \Xw " w JFi = 358.95 C,d 2 VAw This expression is true for any gas, vapor or liquid. When measuring steam with an Orifice Meter the con- necting lines and the gauge itself would be partially filled with condensed water, which would create an erroneous differential reading if the head of water acting on the two 276 MEASUREMENT OF STEAM Table 52-PROPERTIES OF SATURATED STEAM Temp. Deg.Fahr. Heat of the Liquid Latent Heat Total Heat Weight of 1 Cubic Foot, Lb. Volume of 1 U>. ( Cubic Feet Vacuum T_ TV/T^*- t h L H 5 Q An. Jvier. 25 133.2 101.1 1017.0 1118.1 .00689 145.2 20 161.2 129.0 1001.0 1130.0 .0133 75.2 15 178.9 146.8 990.4 1137.2 .0195 51.1 10 192.2 160.1 982.6 1142.7 .0255 39.7 5 202.9 170.9 975.9 1146.8 .0314 31.8 GaugePres. 212.0 180.0 970.4 1150.4 .0373 26.8 5 227.2 195.3 960.6 1155.9 .0491 20.38 10 239.4 207.7 952.5 1160.2 .0607 16.40 15 249.8 218.2 954.5 1163.7 .0721 13.87 20 258.8 227.4 939.2 1166.6 .0834 11.99 25 266.8 235.6 933.6 1169.2 .0946 10.57 30 274 . 1 243.1 928.5 1171.6 .1058 9.47 35 280.6 249.7 923.8 1173.5 .1168 8.56 40 286.7 256.0 919.3 1175.3 .1278 7.82 45 292.4 261.8 915.2 1177.0 .1387 7.20 50 297.7 267.2 911.2 1178.4 .1497 6.68 55 302.6 272.3 907.4 1179.7 .1605 6.23 60 307.3 277.1 903.9 1181.0 .1714 5.83 65 311.8 281.7 900.5 1182.2 .1823 5.49 70 316.0 286.0 897.3 1183.3 .1930 5.18 75 320.1 290.3 894.1 1184.4 .2041 4.91 80 323.9 294.3 891.1 1185.4 .2145 4.66 85 327.6 298.1 888.2 1186.3 .2252 4.44 90 331.2 301.8 885.4 1187.2 .2358 4.24 95 334.6 305.3 882.6 1187.9 .2465 4.05 100 337.9 308.8 880.0 1188.8 .2570 3.89 105 341.1 312.1 877.4 1189.5 .2677 3.735 110 344.2 315.3 874.9 1190.2 .2785 3.592 115 347.2 318.4 872.5 1190.9 .2890 3.460 120 350.1 321.5 870.1 1191.6 .2996 3.338 125 352.9 324.4 867.8 1192.2 .3101 3.226 130 355.6 327.2 865.6 1192.8 .3207 3.118 135 358.3 330.0 863.4 1193.4 .3314 3.018 140 360.8 332.7 861.2 1193.9 .3419 ' 2.925 145 363.4 335.4 859.0 1194.4 .3523 2.839 150 365.9 338.0 857.0 1195.0 .3627 2.758 155 368.4 340.6 854.8 1195.4 .3732 2.680 160 370.7 343.1 852.8 1195.9 .3837 2.606 165 373.0 345.5 850.9 1196.4 . 3942 2.537 170 375.3 347.9 848.9 1196.8 .4046 2.472 175 377.5 350.3 847.0 1197.3 .4151 2.410 180 379.7 352.5 845.1 1197.7 .4256 2.350 185 381.8 354.8 843.3 1198.1 .4364 2.294 190 383.9 357 . 841.5 1198.5 .4464 2.240 195 385.9 359.1 839.7 1198.8 .4564 2.190 200 387.9 361.3 838.0 1199.3 .4670 2.141 210 391.8 365.4 834 . 5 1199.9 .488 2.049 220 395.5 369.3 831.2 1200.5 .508 1.966 230 399.2 373.2 828.0 1201.2 .529 1.889 240 402.6 376.9 824.8 1201.7 .550 1.818 250 406.1 380.6 821.7 1202 . 3 .570 1.752 277 MEASUREMENT OF STEAM portions of the gauge were not equal. To make the heads equal, a reservoir R made of a 12 inch length of 3 inch pipe and two caps, is installed on each gauge line. These reser- voirs are placed horizontal on the same level, above the gauge and connections, tapped in the center of one of the caps for connections to the main and in the bottom for connections in the gauge. When the steam enters the connections, reservoirs, and gauge, it will condense as these are not insu- lated or jacketed, and in a short time the water will fill both portions of the gauge, connections between the gauge and 115 SKETCH OF ORIFICE METER INSTALLATION MEASURING STEAM IN A VERTICAL LINE FOR the reservoirs, and the lower portion of the reservoirs, any excess condensate returning to the main through connec- tions A C and B D. These connections always slope toward the main to avoid trapping any water. Therefore, since the inlets to the reservoir which become the outlets for excess condensation are on the same level, the water pressures on each portion of the gauge are equal and balance one another for all differentials. When the differential h increases the water level at A is lowered and at B is raised, causing a por- tion to flow through the connection B D into the main. In 278 MEASUREMENT OF STEAM the meantime additional condensation is filling the reservoir A to the outlet level. This change of levels in the reservoir, for the short period of time it does exist, is immaterial for the reason that a volume of water equivalent to }^ inch in depth of the reservoir is sufficient to fill the space vacated by the mercury throughout the total range of the gauge. Due to the fact that the recording gauges are filled with water each inch of mercury differential is partially counter- balanced by an inch of water and therefore each inch of mercury differential is equivalent to only 12.6 inches of Direction off/ow Fig. 116 SKETCH OF ORIFICE METER INSTALLATION FOR MEASURING STEAM IN A HORIZONTAL LINE water differential instead of 13.6 inches which would be the case if the water did not fill the connections. Therefore 1 O 5 a correcting factor must be introduced and the differen- 13.6 tial h be multiplied by this factor, for the reason that the gauges are constructed to indicate 13.6 inches of water pres- sure differential for each inch of mercury differential. 279 MEASUREMENT OF STEAM 280 MEASUREMENT OF STEAM 281 MEASUREMENT OF STEAM Table 53 HOURLY ORIFICE COEFFICIENTS FOR STEAM Pressures taken 2^ diameters upstream and 8 diameters downstream. Values of C in Wi= C VhP where Wi=actual weight of saturated steam pass- ing orifice in pounds per hour. Size of meter is diameter of pipe line in which orifice is placed. See Table 54 for correcting factors. Diameter of Diameter of Pipe Line Orifice Inches 4" 6" 8" 10" M 5 /e 2.515 3 950 2.500 2.492 2.490 % V* 5.725 7 857 5.654 5.631 5.617 V/8 IX i*A VA il 10.36 13.26 16.58 20.33 24.58 29.40 10.13 15~99 23*32 10.06 15.80 '22.'9l' 10.02 15~72 '22^72' 1% iii 34.90 41 14 32.20 31.44 31.08 2 2 1 A 48.19 56 23 42.74 41.43 40.84 fyi 2*/ 8 2y 2 2% 2% 2Ve 65.36 76.15 87.76 101.5 117.3 135 2 55.27 69^99 '87^52' 53.04 66~24 81.25 52.05 64^71' '78^95 3 3M 155.8 108.1 132.7 98.28 117.5 94.79 112.1 BH 162 1 139 5 131.8 3/i 197 164.3 153.3 4 4M 4^ 4^ 5 514 238.8 288.6 347.9 192.4 224.7 260.9 303.1 350.2 405 4 177.0 203.1 232.1 264.0 299.3 338.7 5 1 A 468.4 381.6 &A 539.3 430.2 6 6M 620.8 483.4 542.8 Q 1 A 609.2 6% 683.1 7 765.7 7M 856.9 7^ 957.3 282 MEASUREMENT OF STEAM Table 54 MULTIPLIERS FOR VARIOUS GAUGE PRESSURES, MOISTURE, AND SUPERHEAT Used with Table 53. Percent- Static Pressure Pounds Gauge Moisture 25 50 100 150 200 250 30 1.232 1.214 1.195 1.184 1.177 1.173 25 1.191 1.173 1.155 1.145 1.138 1.134 20 1.153 1.135 1.117 1.107 1.100 1.097 15 1.119 1.102 1.085 1.075 1.069 1.064 10 1.087 1.071 1.054 1.045 1.038 1.034 5 1.058 1.042 1.026 1.017 1.011 1.007 3 1.046 1.031 1.015 1.006 1.000 .997 2 1.041 1.026 1.010 1.001 .995 .992 1 1.036 1.021 1.005 .996 .990 .987 1.031 1.016 1.000 .991 .985 .981 Super- heat deg. fahr. 20 1.016 1.001 .985 .976 .970 .967 50 .992 .978 .961 .952 .945 .940 100 .950 .945 .929 .919 .911 .904 150 .930 .915 .899 .889 .882 .877 200 .902 .890 .874 .863 .855 .846 250 .878 .866 .850 .839 .832 .826 300 .855 .843 .829 .819 .811 .805 400 .818 .806 .792 .781 .773 .768 500 .781 .770 .760 .750 .743 .737 The weight of steam per cubic foot varies approximately with the absolute pressure. w = . 002241 P Where w = weight of steam in pounds per cubic foot. P = the static pressure of steam expressed in abso- lute units being equal to the gauge pressure plus the atmospheric pressure. MEASUREMENT OF STEAM Substituting these factors in T^i = 358.95 C v d V h w nr u* - w/ OKQOK ^^2 12.6 AX. 002241 P We obtain T7 1 = 358. 95 C v d\\- * 13.6 or JFi = 16.36 C^ 2 VTP = C VTP Where TFi is equal to the actual weight of dry steam pass- ing the orifice in pounds per hour. The Hourly Orifice Coefficient, C in Table 53, is equal to 16.36 C v d 2 . The multipliers for revision of the Coefficients are de- termined by substituting the weight of the unsaturated or superheated steam in pounds per cubic foot (Page 277,) for w in the formula. These multipliers may be applied either to the coefficient or the calculated result. The main purpose in measuring steam is to determine the amount of heat or power furnished by the boiler and supplied to the heat or power consuming units. The amount of steam power produced and consumed is ex- pressed in "pounds from and at 212 deg. fahr." This term is a steam engineer's unit of measurement just as one of the units for the measurement of gas is a "cubic foot at 60 deg. fahr. at 4 ounces pressure." The expression "pound from and at 212 deg. fahr." is a unit of heat measurement being equal to 970.4 B. t. u., the number of heat units required to convert one pound of water "from" 212 deg. fahr. into dry steam "at" that temperature. A boiler horse power is equivalent to 34 y% "pounds of steam from and at 212 deg. fahr." The number of "pounds from and at 212 deg. fahr." may be either greater or less than the actual weight. For example, it takes 11587 B. t. u. to convert 10 Ib. of water from 62 deg. fahr. into dry steam at 100 Ib. gauge pressure and therefore the heat supplied to or the power content of the 10 Ib. of steam is equal to 11587 B. t. u. divided by 970.4 B. t. u. or 11.94 "pounds from and at 212 deg. fahr." If the tempera- 284 MEASUREMENT OF STEAM ture of the water were 72 deg. fahr. or 10 degrees higher than the previous instance, the heat absorbed would be 11487 B. t. u. or equal to 11.83 "pounds from and at 212 deg. fahr.," about 1 per cent less. Although the actual weight is not changed the heat absorbed does change. The heat content of 1 Ib. of steam at 100 Ib. gauge pressure above water at a temperature of 62 deg. fahr. is 1158.7 B. t. u. and at 250 Ib. pressure is 1172.2 B. t. u. above same temp- erature base. In other words, the unit "pounds from and at 212 deg. fahr." is the steam engineer's "yard stick." The power passing through the line could be expressed in B. t. u. just as well as in "pounds from and at 212 deg. fahr," except that the B. t. u. unit is so small. Furthermore, this expres- sion has become firmly established in the steam engineers' vocabulary by universal usage. Just as in measuring gas or any fluid, whose volume per pound is affected by pressure and temperature, bases are established, so in measuring steam a temperature base is established from which all calculations are made. In gas measurement an average temperature of 60 deg. fahr. and an atmospheric pressure 14.4 Ib. per sq. in. are used as bases. In calculating the value of the Hourly Orifice Coefficients for the measurement of the flow of steam (Page 287) we have used 62 deg. fahr. (a low feed water temperature) as a temperature base above which the heat content is expressed. The heat content of steam for various pressures may be found in the Table of Properties of Steam, Page 277. The total heat content of steam for various pressures in this table is expressed above a temperature base of 32 deg. fahr. and to change to a base of 62 deg. fahr. 30.1 B. t. u. should be subtracted. The total heat content of steam at 100 Ib. gauge pressure is 1188.8 minus 30.1 or 1158.7 B. t. u. above a temperature base of 62 deg. fahr. To express the weight on the basis of heat units or W weight per hour in "pounds from and at 212 deg. fahr," 285 MEASUREMENT OF STEAM we assume an average heat content of saturated steam per pound for all pressures as 1158.7 B. t. u. above a temper- ature base of 62 deg. fahr. This is an approximation but the net effect of using this value nearly cancels the error in- volved in assuming the value of w as equal to .002241 P for all pressures. B. t. u. per pound "from and at 212 deg. fahr. " = 970. 4. Then one pound of steam = '^ = 1.194 "pounds from 970.4 and at 212 deg. fahr." Or JF = 1.194 multiplied by the actual weight. Where W = quantity of steam passing the orifice per hour in "pounds from and at 212 deg. fahr." W = 1. 194 X 16.36 C v 727 4 &A 815 6 7 914 3 7V* 1023 iy 2 1143. 287 MEASUREMENT OF STEAM Table 56 MULTIPLIERS FOR GAUGE PRESSURE, MOISTURE, SUPERHEAT AND FEED WATER TEMPERATURE To be used in connection with Table 55. Gauge Pressure Pounds Percentage of Moisture Saturated Steam Superheat deg. fahr. 20 15 10 5 50 100 200 300 500 25 50 100 150 250 Feed Water Temperature 32 deg. fahr. 25 .977 .994 1.009 1.024 1.040 1.022 1.008 .986 50 .975 .990 1.005 1.019 1.033 1.017 1.003 .982 100 .976 .990 1.002 1.014 1.026 1.010 .996 .975 150 .978 .990 1.000 1.011 1.022 1.007 .992 .969 250 .982 .991 .999 1.009 1.017 1.003 .986 .962 .970 .950 .966 .946 960 .941 .955 .938 .949 .931 Feed Water Temperature 62 deg. fahr. .947 .965 .981 .997 1.013 .996 .983 .963 .948 .930 .946 .962 .978 .992 1.007 .992 .978 .959 .944 .926 .948 .961 .974 .988 1.000 .985 .972 .952 .938 .921 .949 .962 .973 .985 .996 .982 .968 .947 .934 .918 .954 .964 .972 .983 .992 .979 .963 .940 .928 .912 Feed Water Temperature 92 deg. fahr. 25 .917 .936 .953 .970 .987 .971 .958 .939 50 .917 .933 .950 .965 .980 .966 .954 .936 100 .919 .933' .947 .961 .975 .961 .948 .930 150 .921 .934 .946 .958 .971 .958 .944 .924 250 .926 .936 .945 .957 .967 . 954 . 940 .919 .926 .910 .922 .906 .917 .902 .913 .899 .907 .893 __ _ Feed Water Temperature 122 deg. fahr. 25 .888 .907 .924 .942 .960 .945 .933 .916 50 .887 .905 .922 .938 .954 .941 .929 .913 100 .890 .905 .920 .935 .949 .936 .924 .907 150 .892 .906 .919 .932 .945 .933 .920 .902 250 .897 .909 .918 .931 .941 .930 .916 .897 .903 .890 .900 .886 .895 .882 .892 .879 .886 .874 Feed Water Temperature 152 deg. fahr. 25 .858 .878 .896 .915 .933 .919 .909 .893 50 .858 .876 .894 .911 .928 .916 .905 .890 100 .861 .877 .893 .908 .923 .911 .900 .884 150 .863 -.879 .892 ,906 .919 .908 .897 .880 250 .869 .881 .892 .905 .916 .906 .893 .875 .881 .869 .879 .866 .874 .862 .870 .860 .866 .855 Feed Water Temperature 182 deg. fahr. 25 .828 .849 .868 .887 .907 .894 50 .828 .848 .867 .884 .901 .890 100 .832 .849 .865 .882 .897 .884 150 .835 .851 .865 .879 .894 .883 250 .840 .854 .865 .879 .890 .881 .884 .880 .867 .876 .862 .873 .869 .857 .853 .859 .849 .857 .846 .852 .843 .849 .840 .845 .836 _ Feed Water Temperature 212 deg. fahr. 25 .798 .820 .840 .860 .880 .868 .859 .846 50 .799 .819 .839 .857 .875 .865 .856 .844 100 .803 .821 .838 .855 .871 .861 .852 .839 150 .806 .823 .838 .853 .868 .859 .849 .835 250 .812 .826 .838 .853 .865 .857 .846 .831 .837~7829 .835 .826 .831 .823 .828 .824 821 817 288 MEASUREMENT OF STEAM The steam as measured usually contains the same per- centage of moisture or amount of superheat and therefore the multiplier can be either applied to the hourly coefficient for the orifice or to the result. Table 57 HORSE POWER "POUNDS FROM AND AT 212 DEG. FAHR." TT Pounds from and at 212 deg. fahr. Units of Evapo- ration or "pounds from and at 212 deg. fahr." Horse Power 1 34.5 1 .028986 2 69.0 2 .057971 3 103.5 3 .086957 4 138.0 4 .115942 5 172.5 5 .144928 6 207.0 6 .173913 7 241.5 7 .202899 8 276.0 8 .231884 9 310.5 9 .260870 Due to the fact that steam does not accurately follow the law of perfect gases, slight revisions were required for various gauge pressures, the Tables being calculated for 100 pounds gauge pressure. It will be noted in the Table of Multipliers, Page 288, that the percentage differences between the multipliers are very small for wide differences in the percentage of moisture and quantity of superheat. The gain or loss in weight per cubic foot and loss and gain in heat content per pound partially offset each other. For this reason the orifice meter is most adaptable for the direct measurement of power. The following examples illustrate the use of the Multipliers for revision of Coefficients. Example Steam being measured. Gauge Pressure, 200 Ib. per square inch. Internal diameter of line, 6.065 inches. Diameter of orifice, 3 inches. 5 per cent moisture. Feed Water Temperature 182 deg. fahr. Actual weight desired. 289 MEASUREMENT OF STEAM In Table 53, Page 282, the Coefficient for a 6X3 orifice is 108.1, the Multiplier for revision is 1.011 (Table 54, Page 283) for 200 Ib. static pressure containing 5 per cent moisture. The New Coefficient = 108. IX 1.011 = 109.3. If the power is desired in Table 55, Page 287, the Co- efficient for a 6X3 orifice is 129.1, the Multiplier for 200 Ib. static pressure, feed water temperature 182 degrees, 5 per cent moisture is .879. Table 56, Page 288. The New Coefficient =129. IX. 879 = 113.5. Therefore, a 6X3 orifice will pass 113.5 Ib. of steam (from and at 212 deg. fahr.) at a theoretical absolute pressure of 1 Ib. and at one inch differential per hour. The values of C, the Hourly Orifice Coefficient for steam, contained in Tables 53 and 55, are prepared for pipe of standard dimensions (4.026, 6.065, 8.071, 10.191 inches in- ternal diameter) . Coefficients for pipes of other internal di- mensions can be derived as follows. Example Steam being measured. Internal diameter of pipe 3.548. Diameter of Orifice 2J4 inches. Actual Weight desired. 2 25 C v for ratio .6342 = .877 (Page 210). Coefficient = 16.36 C v d 2 = 16.36X. 877X2.25X2.25 = 72.64 Ib. of steam per hour. The Multipliers applicable to Table 53 should be used where the pressure and quality of steam differ from 100 Ib. gauge and saturated steam. 290 MEASUREMENT OF STEAM I i I 1 w ? O si P"H JS I II 2 o s.a g s s = 8 !S 8 00 -^ O O b- O5 i-H O5 00(M t- r I r I CM Cvj 8 O^2 O^ O O O O O5 i i l-t C\J Tj< 10 8 O O O O5 CM t- (M T!< lO O O ' CO t- O O OS "tf CM rH i I OJ CO 00 1C 00 O O t- rH t> T*< rJH rH i-H I" 3 O S a 1 * o c . * e g OS 0) is a & erem EH $ ft la Y CAPAC iameters dowi s diameter of 50 Inch Di: ^ T3 ^4 g 00 1 S 3 ! H -| X M I I 8 8 8 . ^^-^ rt -ri > 292 MEASUREMENT OF STEAM Table 60 SIZE OF ORIFICES FOR MEASURING STEAM Pressures taken 2^ diameters upstream and 8 diameters downstream. Weight expressed in pounds of steam per hour. 50 inch Chart. Size of Meter is diameter of pipe line in which orifice is placed. 2 Inch Meter 3 Inch Meter 4 Inch Meter Pounds per Gauge Pressure Pounds Gauge Pressure Pounds Gauge Pressure Pounds Hour 25 50 100 200 25 50 100 200 25 50 100 200 200 K ^ y% K N 7* Ys K K M 8* K 300 i /4 i % ^8 i K N 400 iK i K /4 IK 1 K %/ iK i K 600 1M iK i K ! 3 /8 1/4 i y* IN IK iK i 4 800 IN IK iK i IK 1^1 1M i 1^ 1^ iK 1000 IK IN 1M iK 1M IK IN iK 1^4 1^ 1^ 1)4 1500 iK 13/^ 2 i^ 1% 13/^ 2 IK IN iK 2000 3000 IK IK 2J4 2M 2 1/4 2 1^4 2K 2K 1M IN 2 4000 2K 2 3 2K 2K 6000 2K 3 2^4 2K 8000 3 gs^ 10000 3 6 Inch Meter 8 Inch Meter 10 Inch Meter Pounds per Gauge Pressure Pounds Gauge Pressure Pounds Gauge Pressure Pounds Hour i 25 50 100 200 25 50 100 200 25 50 100 200 400 IK 1 K % ! M 1 K % IK 1 K ^4 600 IK 1/4 iK 1 IK iK 1 IK IK i 800 IN IK IK 1% 1/4 iK IK iK IK 1000 IK iK iK iK i/4 IK ik 1/4 IK 1500 2 4 IK 2K 2 1M 2H 2 IN IK 2000 2K 2K 2 1^4 2% 2M 2 i^ 2% 2 3^ 2 IX 3000 3 2K 2 3 2M 2K 2 3 2K 2K 4000 3K 3 2M 2/ / g 3K 3 2/4 2K 3K 3/4 2J/8 2/ / 8 6000 4 3K 3 2^ 434 3/4 3M 3 4J4 4 3K 3 8000 4K 4 3K 4K 4M 3M 5 4K 4 3K 10000 4K 4M 4 3K 5 4K 4 3K 5K 5 4K 3^4 15000 4K 4K 4 5K 5K 5 6/4 5K 5 4K 20000 4/4 6 6 SK 4^4 6/4 6K 5% 5 30000 6 5K 7K 6K 6 40000 6 6K 60000 7K 293 MEASUREMENT OF STEAM STEAM COEFFICIENT TESTS The following tests are a portion of series of tests which were conducted at the Metric Metal Works several years ago. The layout shown on Page 149 was used, in which a por- tion of the steam from the main header was measured through an orifice and subsequently weighed as condensate by passing the steam into a barrel of cold water. Table 61 Orifice Static Pressure Ib. Differ- ential Time Hr. Quan- tity Ib. Coeffi- cient Remarks Pipe Tap Connections 4"x M" 103.5 32.3 .0766 22.75 5.80 4"x W 100.0 2.3.7 .0883 26.75 5.82 4"x %" 88.0 39.7 .0568 20.5 5.65 5.72a 4"x Y" 95.0 29.6 .0723 23.0 5.53 5.75c 4"x M" 99.0 18.5 .1231 32.75 5.80 4"x % 105.0 31.0 .1078 37.5 5.71 4"x %* 102.0 37.8 .0874 33.25 5.73 4"x Yz" 102.0 18.5 .2750 32.5 2.54 4"x Y 2 " 106.0 20.2 .2663 33.5 2.54 4"x W 110.0 20.3 .2687 35.0 2.58 4"x W 102.0 18.8 . 2713 32.5 2.56 4"x Y 2 " 98.0 19.4 .2585 31.0 2.57 2.54a 4"x Y 2 " 101.0 21.2 .2845 35.25 2.51 2.53c 4"x W 96.0 21.0 .2833 34.0 2.50 4"x W 103.0 26.0 .2072 29.0 2.53 4"x Y 2 " 100.0 3.6 .5000 25.0 2.46 4"x W 101.0 5.4 .4525 29.5 2.61 4"x ^" 102.0 22.0 .2400 30.5 2.51 4"xl" 98.0 30.7 .0605 37.0 10.42 4"xl" 97.6 35.0 .0555 36.0 10.35 10.44a 4"xl" 89.8 21.9 .0614 30.5 10.45 10.41c 4"xl" 107.0 43.6 .0415 30.5 10.10 Flange Connections 4"xl" 109.5 53.0 .0547 44.5 10.04 4"xl" 100.0 42.0 .0536 35.75 9.63 9.80a 4"xl" 110.5 32.5 .0702 44.0 9.84 9.90c 4"xl ;/ 101.5 43.0 .0537 36.75 9.70 In the column Remarks, (a) refers to the average value of the Coefficient obtained by the tests and (c) is the calculated value of the Coefficient obtained by assuming that the coefficient of velocity of steam is the same for steam as for air. 294 MEASUREMENT OF STEAM Preliminary tests indicated a serious discrepancy be- tween the coefficients as obtained by the tests and the co- efficients as obtained by calculating the value assuming the coefficient of velocity of steam the same as the coefficient of velocity for air. These discrepancies were attributed to condensation and after the lines were thoroughly insulated they continued with the result that the deviation was found to be due to pulsation as explained on Pages 146 to 151. Previous experiments by French scientists have shown that the flow of steam through orifices indicated that the coefficient of velocity for steam and air was the same. In order to verify the previous results, a portion of the tests were made when there were no reciprocating units connected with the line and a portion were conducted when the reciprocating units were operating. By making proper deduction for pulsation, as indicated before and after the test, the results obtained compared favorably with the results in cases where the reciprocating units were not in operation. As is noted the duration of the tests was very limited and the amount of condensate obtained was com- paratively small. However, the above results indicate that the results obtained by early experimenters were correct. In addition to the above series of tests, numerous tests have been conducted using the orifice meter and differential gauge by various refineries in which the duration of the tests lasted for several hours and in which condensate amounted to several hundred pounds where the percentage of moisture ranged from to 15 per cent. The coefficients obtained in these tests ranged within 1 per cent of the published coefficients, some of them being higher and some lower and the average deviation was less than one-half of 1 per cent. Some manufacturers of steam flow meters drill a small opening in the orifice disc below the orifices, even with the level of the lowest surface of the pipe when the orifice is 295 MEASUREMENT OF STEAM installed in a horizontal line. This small opening is based on the theory that any condensate forming ahead of the orifice will pass through the small opening. Subsequent tests have indicated that such an opening is entirely un- necessary in actual practice, for the reason that all of the moisture is carried through the orifice by the steam and that after the orifice has been in service a few moments no moisture can be obtained from a bleeder placed just ahead of the orifice. INSTALLING AND TESTING STEAM METERS See Pages 303 and 304. To successfully measure steam with an orifice meter violent pulsation and vibration must be eliminated. The steam main should be opened at a flange connection, old flanges removed and new flanges installed. The orifice disc is placed between the flanges using sheet asbestos gas- kets shellaced to the flanges on each side of the orifice disc. When pressures are taken at the flanges installed in a horizontal line, the flanges should be set up so that the con- nections are on the side or on the top. In drilling openings for connections where the pressures are taken at points 2^ diameters upstream and 8 diameters downstream from the orifice, the taps should be on level with the center of the pipe or on top of the pipe if the main is a horizontal line. Connect the taps in the main or at the flanges with reser- voirs each constructed of either a 12 inch length of 3 inch pipe or 2 feet of 2 inch pipe. The tap in the reservoir should be at the middle point of the reservoir either at the side or in the end. Place the reservoirs in a horizontal position level with each other. Taps for connections from the reservoirs to the gauge should be in the bottom of the reservoirs. The pipe lines between the reservoirs and the main line should always drain toward the main. The reservoirs must be at the highest point in 296 MEASUREMENT OF STEAM the gauge line connection. Do not place reservoirs close to the main as it is desirable to keep them cool. However, they must be higher than the gauge. Connect the reservoir (attached to the downstream con- nection D on the main), at tap in the bottom, with gauge at tap L. Place valve X in the line adjacent to the gauge. Connect upstream reservoir, at tap in the bottom, with the gauge at tap H placing valve W near the gauge. Install a by-pass placing valves at Z and Y and a pet- cock or valve at K. The reservoirs when in operation will be half filled with water, level with the connection from the reservoirs to the main. The gauge lines from the reservoir to the gauge and the gauge itself will be filled with water when in operation. Therefore, in order to maintain a balanced pressure on both sides of the gauge due to condensation, the reservoirs must be level with each other and higher than the gauge itself. Valves near U and D are auxiliary valves used in long lines. Setting up Gauge, Glass, Differential Pen Arm, Adding Mercury, Clock, Placing Chart, Pens and Ink, Vibrating Pen Arm, and Adjustments. See the remarks contained under these various headings for measurement of gas. They apply for measurement of steam. See Pages 247 to 250. Static Pen Arm The static pressure arm will rest at a pressure equal to the head of water in the reservoir above the elevation of the static spring when there is no pressure in the main. Thus, if the reservoirs are llj^ feet above the elevation of the static spring the pen should rest at 5 pounds, one pound being equivalent to 2.3 feet water head. The static pen can be adjusted to eliminate this difference by setting on zero when the gauge, gauge lines and reservoirs are filled with water. 297 MEASUREMENT OF STEAM Turning on Steam Before turning steam pressure into gauge fill the gauge with water, Open K, Y and Z Then open W and X very slowly to admit water to the gauge and lines and release air through valve at K and at funnel. Close X After the air is eliminated close funnel Close Y and Z Open X K should be left open Be sure that valves Y and Z do not leak. Orifice Capacities After the gauge is in operation if the differential pen arm records near the maximum reading change the orifice to one of a larger size. If this is not pos- sible and it is found that the flow of steam keeps the marking arm at or above the maximum differential circle it will be necessary to use a differential gauge of a higher range of differential. If, after 24 hours, the differential reading is at or below 10 per cent of the maximum range of the chart in inches, change the orifice for one of a smaller size or use a differential gauge with a smaller maximum range. For Orifice Capacities see Pages 291 and 292. Checking Differential Gauge for Zero : Open Y slightly until water flows from K Close K Close W and X Open Y and Z, then open K The differential pen arm should return to zero. Buoyancy of Float The zero position of the pen arm in a gauge filled with water is not the same as when filled with air due to the increased buoyancy of the float on account of the water. 298 MEASUREMENT OF STEAM Fig. 119 DIFFERENTIAL GAUGE WHICH INDICATES RATE OF FLOW PER HOUR. SEE PAGES 130 AND 131. Patent applied for 299 MEASUREMENT OF STEAM Zero Float Position The differential pen arm should be kept in a straight line at, the flexible joint. The differential pen arm can^be adjusted to zero by moving slightly at the flexible joint or at the connection with the shaft. When the pen arm rests at zero determine if the float is floating and not resting on the bottom of the mercury pot. Partially close Y Open X carefully when the differential pen should recede one-fourth inch or more (actual measurement) below the zero line. If the float rests on the bottom of the chamber at zero add mercury. See paragraph Adding Mercury, Page 247. After test, close X Open Y Checking Differential Pen Arm Close W and X Attach a single column glass tube with a rubber connection and nipple to tap at P and fasten tube in a rigid vertical position. See Figs. 120 and 121 for examples. Open K, Y and Z Open W and admit water slowly to expel air fromK Mark level of water in glass tube attached to connection at P Close Z By partially opening and closing W the reading can be checked with the column of water in the tube above the zero mark. One inch of water reading on the chart is equal to 0.926 inches of water head in the glass column above the zero position. The following Table indicates the various check readings. 300 MEASUREMENT OF STEAM Table 62 CHECK READINGS FOR DIFFERENTIAL GAUGE FILLED WITH WATER Differential Water Column Differential Water Column Gauge Reading Head Gauge Reading Head Inches Inches Inches Inches 1 .93 10 9.3 2 1.85 20 18.5 3 2.77 30 27.7 4 3.71 40 37.1 5 4.63 50 46.3 6 5.56 60 55.6 7 6.49 70 64.9 8 7.41 80 74.1 9 8.34 90 83.4 100 926 After Test, open Z, close P, then proceed as in Turning on Steam, Page 298. The differential pen arm may be tested as in testing with gas if the water is removed from the gauge and air pressure is used. Fig. 120 Fig. 121 Showing typical methods of ' attaching tube for water column test. Points K and P may be located at other openings as shown in the various installations. 301 MEASUREMENT OF STEAM Testing Static Spring To test the static pressure gauge, attach the test gauge at G, and check the two gauges. If the static spring is adjusted for head of water in gauge lines and reservoirs above the gauge, in testing, the adjust- ment should be added to the static pressure arm reading to check with the test gauge. See same subject, Page 258. Leaks Watch all connections for leaks. There should be no leaks at any connection. Special attention should be given to valve stems for leakage. General Before turning the pressure into the gauge, always make sure valves W and X are closed before opening valves Y and Z or either Y or Z. This precaution will eliminate the circulation of water through the by-pass, and heating of the gauge lines. Fig. 122400 INCH GAUGE USED FOR TESTING PURPOSES 302 MEASUREMENT OF STEAM Upstream Connection Downstream Connection ' Sect/on M-M Jest Conn e> Mart X Test Connect /on Differential Pressure Gauge ryDram Fig. 12350 INCH GAUGE INSTALLATION FOR MEASURING STEAM 303 MEASUREMENT OF STEAM Upstream Connection J- ffeserw/rs- Test Connection Different/a/ Pressure fa upe tinnect/o/? 'era/ft/ Drain Cnort Fig.l2450or 100 INCH GAUGE INSTALLATION FOR MEASURING STEAM 304 MEASUREMENT OF STEAM READING CHARTS The formula for use in measuring steam with the orifice meter is Quantity = C C = Coefficient obtained from Table of Coefficients or calculated for the proper size of orifice, diameter of pipe, quality and pressure. h = differential pressure in inches of water. A atmospheric pressure in Ib. per square inch. p = static pressure expressed in Ib. per square inch. To simplify all calculations, Tables of Pressure Extensions have been published which give the results of the formula in figures for various combinations of pressure and differential readings from 29 inches vacuum to 500 Ib. pressure and from 1 inch to 100 inches differential. This eliminates the ne- cessity of figuring out the formula for each reading in deter- mining the volume of steam passing the meter. In this formula, the atmospheric pressure is assumed as 14.4 Ib. Adjustment must be made to the static pen arm, or to the static pressure readings as explained on Page 297, on account of the elevation of the reservoirs above the gauge. To obtain the quantity passing the meter, average the differential pressure (marked in red ink) and the static pres- sure (marked in black ink) on the chart for each hour. If the differential pressure varies over wide ranges during the daily period, the method used for gas should be applied. As the static pressure is usually fairly constant, average the differential reading for the day and the static reading for the day. The pressure extension is obtained for the average readings and is multiplied by the number of hours for which the average was obtained. This product is then multiplied by the Hourly Orifice Coefficient. 305 MEASUREMENT OF STEAM Frequently a planimeter and reference chart is used to obtain the average differential reading and average static reading. This method eliminates the necessity of recording the differential and static pressures on the chart and greatly simplifies the work. It should only be used when the static pressures or differential pressures do not vary over wide limits, as the results in such cases will be greater than the true result. The pressure carried in steam lines does not usually vary over wide ranges, and quite frequently is almost constant. Due to this fact, the static pressure is not recorded by some makes of flow meters, thus these meters have a semblance of simplicity which does not really exist. Meters which record the static pressure as well as the differential pressure give the operator an accurate report of the condition at the meter. When the static or line pressure is constant the work in- volved in obtaining the flow is greatly simplified. The form- ula C-\/ hP can be reduced to C s V h in which C s is equal to C VP P being the pressure extension for one inch differential. This steam Coefficient C s is used as a multiplier for the sum of the hourly values of V~& (Page 313). Example Line Pressure, 100 Ib. Pipe Diameter, 4 inches. Orifice Diameter, 2J/ inches. C = 87.76 (Page 282) C s = 87.76 V 100+14.4 -87.76X10.696 = 938.7 This Steam Coefficient is also used as the multiplier for the average differential reading obtained by using a planimeter and multiplying by 24. All Orifice meter chart calculations are simplified by the use of the Orifice Meter Calculator, Page 267. 306 PART SIX MEASUREMENT OF WATER. The type of meter and gauge used for measuring water is identical with that used for measuring gas or air, with the exception that the static pressure spring may be omitted as water and oil are practically incompressible. The same types of charts are used, reducing to a minimum the various styles and amounts of supplies required, not to mention the decrease of maintenance and inspection. The operator needs to be familiar with only one type of meter and the office work is greatly simplified as only one kind of chart is to be read. The measurement of water by the orifice meter is greatly simplified due to absence of all multipliers for revision of coefficients. For each installation the orifice in the orifice disc, when placed in the pipe line, forms a definite section of unchanging area, and creates a definite difference between the static pressure of the fluid on the upstream side of the orifice, and the static pressure of the fluid on the downstream side of the orifice, for each velocity or rate of flow of the fluid, at the same density. This difference in static pressures is termed the differential pressure or the "differential." In other words the "differential," in cases of liquids, indicates the velocity. The Differential Gauge records on a chart the differential pressure existing between the pressure connections. This factor with the known area of the orifice enables us to de- termine the flow from the formula: 307 MEASUREMENT OF WATER Where () = the Quantity of liquid passing the orifice. The result can be expressed in "gallons" or "barrels" per hour. C = the Hourly Coefficient. The value of this term remains the same for each installation and basis of measurement. h = the Differential Pressure existing between the two pressure connections, expressed in inches of water head, this value is recorded graphi- cally on the chart of the Recording Dif- ferential Gauge. The value of the Hourly Orifice Coefficient C in the above formula is found on Page 312, computed for various diameters of orifice and diameters of pipe, these values having been determined by exhaustive experimental and practical tests in comparison with actual displacement. The extensions of the values of V h have been compiled and are given in Table 64. Example One hour reading (water being measured) : Average differential reading h = 25 inches. Diameter of Pipe= 4 inches. Diameter of Orifice = 2 inches. Hourly Orifice Coefficient C = 963.1 for 2 inch orifice in a 4 inch line (Page 312). Quantity per hour, Q = 963.1 V25 Orifice Pressure = 963.1 X 5.000 = 4816 gallons. Coefficient Extension. Therefore the quantity per hour flowing in the line is equal to the Orifice Coefficient multiplied by the Differential. 308 MEASUREMENT OF WATER The relation between the differential and the velocity of the fluid through the orifice is expressed by the formula: Where V ' velocity of flowing fluid in feet per second. g = acceleration due to gravity in feet per sec., per sec. -32.16. H = differential expressed in feet head of flowing fluid. The well known formula V= ^j2gH expresses the theo- retical flow eliminating friction and other influences. When applied to actual conditions a correcting factor is used to take care of influences due to contraction of jet, friction, etc. This correcting factor C v is commonly known as the "co- efficient of velocity." In this formula the differential head is expressed in feet head of flowing fluid : Where H = differential in feet head of flowing fluid. h = differential in inches of water pressure. 12 = number of inches in a foot. Substituting the value of H in formula V = C Weobtain F= = 2.31520 In measuring water with an orifice meter the connecting lines and the gauge itself are filled with water, thus the heads of liquid acting on each portion of the gauge are equal. 309 MEASUREMENT OF WATER Due to the fact that the recording gauges are filled with water each inch of mercury differential is partially counter- balanced by an inch of water. Each inch of mercury dif- ferential is equivalent to only (13.6 1.0) inches of water differential instead of 13.6 inches which would be the case if the water did not fill the gauge and connections. Where 13. 6 = specific gravity of mercury. 1.0 = specific gravity of water in gauge. Therefore, the differential h is multiplied by the factor 12.6/13.6 for the reason that differential gauges are con- structed to indicate 13.6 inches of water pressure differential for each inch of mercury differential. Substituting these factors in V = 2.3152 C,VT we obtain 12.6ft 13.6 The quantity of water passing the orifice in gallons per hour is equal to the area of the orifice in square inches multi- plied by the velocity in inches per hour divided by 231. This fact may be expressed by the following formula : 0.7854 d 2 Q= X3600XFX12 ZoL <2 = 146.88 <2 2 XF W r here Q = quantity of water passing the orifice in gallons per hour. 0.7854 d 2 = area of orifice in square inches. d = diameter of orifice in inches. 231 = number of cubic inches in a gallon. 3600 = seconds in one hour. F = velocity of water through orifice in feet per sec. 12 = number of inches in a foot. 310 MEASUREMENT OF WATER Substituting the value of V where 7 = 2.2284 C v ^~h in this expression. Q= 146.88^ 2 X2.2284C,Vl Q = 327.31 C^ 2 V"A = CV"A The Hourly Coefficient C in Table 63 is equal to 327.31 C v d 2 . It has been found that the simple layout shown in Figs. 125 and 126 can be used very satisfactorily for measuring light oils or oils of low viscosity, see Part 7. The values of C, the Hourly Orifice Coefficients for Water, are given in Table 63. These Coefficients are prepared for pipe of standard dimensions (2.067, 3.068, 4.026, 6.065, 8.071 and 10.191 inches internal diameter). Coefficients for pipes of other internal diameters for various sizes of orifices can be calculated as follows. Example Water being measured. Internal Diameter of Pipe 7.981 inches. Diameter of Orifice 4 inches. Ratio X = . 5012 7.981 C v for ratio .5012 = .739 (Page 209). Coefficient =327.31Qf = 327.31 X. 739 X4X4 = 3870 gallons per hour. 311 MEASUREMENT OF WATER Table 63 HOURLY ORIFICE COEFFICIENTS FOR WATER Pressures taken 2J/ diameters upstream and 8 diameters downstream. Values of C in Q = C V h where Q expresses the quantity of water passing through the orifice in gallons per hour. Size of Meter is the diameter of pipe line in which orifice is placed. Diam. of DIAMETER OF PIPE LINE unnce Inches 2" 3" 4" 6* 8" 10" y* 5 A H 7 A 51.69 82.42 122.1 172 8 50.68 79.96 116.4 160 5 50.22 79.04 114.7 157 3 113^0 1 iy<. 237.7 321 2 213.1 275 3 207.2 264 8 202.8 200.9 IK i*A m 1% IK 2 2 1 A 429.3 569.7 752.2 348.6 435.2 537.5 658.8 802.9 974.9 1180. 1424 330.7 405.8 491.1 587.7 697.3 821.6 963.1 1124 320.0 466 642*8 853.7 316.1 458.6 628~9 '828^5 313.8 454^5 622^ i 817!2 2X 2% 1716. 1308. 1518 1104. 1059. 1041. 2 1 A 2% 2% 2y s 3 &A ay 2 &A 4 4M V/2 &A 5 5K 1758. 2033. 2347. 2707. 3118. 1399. 1749 ! 2162 !' 2654. 3240. 3940. 4777. 5776. 6973. 1323. 1623 ! 1963 ! 2349. 2787. 3283. 3848. 4491. 5224. 6060. 7017. 8112 1294. 1577! ' 1893 '.' 2244. 2632. 3061. 3535. 4057. 4636. 5275. 5982. 6766. 5U 9364 7635. 5M 10800 . 8600. 6 12430 . 9674. 6M 10870. Q 1 A 12190. 6% 13670. 7 15310 . 7M 17130. 7^ 19160. 312 MEASUREMENT OF WATER Table 64 DIFFERENTIAL PRESSURE EXTENSIONS Values of V7T from 1 to 100 Inches Differential Reading h Inches Extension VT Differential Reading h Inches Extension VT Differential Reading h Inches Extension VT 1.0 l.COO 8.4 2.898 45 6.708 1.1 1.049 8.6 2.933 46 6.782 1.2 1.095 8.8 2.966 47 6.856 1.3 1.140 9.0 3.000 48 6.928 1.4 1.183 9.2 3.033 49 7.000 1.5 1.225 9.4 3.066 50 7.071 1.6 1.265 9.6 3.098 51 7.141 1.7 1.304 9.8 3.130 52 7.211 1.8 1.342 10.0 3.162 53 7.280 1.9 1.378 10.2 3.194 54 7.348 2.0 1.414 10.4 3.225 55 7.416 2.1 1.449 10.6 3.256 56 7.483 2.2 1.483 10.8 3.286 57 7.550 2.3 1.517 11.0 3.317 58 7.616 2.4: 1.549 11.5 3.391 59 7.681 2.5 1.581 12. 3.464 60 7.746 2.6 1.612 12.5 3.536 61 7.810 2.7 1.643 13. 3.606 62 7.874 2.8 1.673 13.5 3.674 63 7.937 2.9 1.703 14. 3.742 64 8.000 3.0 1.732 14.5 3.808 65 8.062 3.1 1.761 15. 3.873 66 8.124 3.2 1.789 15.5 3.937 67 8.185 3.3 1.817 16. 4.000 68 8.246 3.4 1.844 16.5 4.062 69 8.307 3.5 1.871 17. 4.123 70 8.367 3.6 1.897 17.5 4.183 71 8.426 3.7 1.924 18. 4.243 72 8.485 3.8 1.949 18.5 4.301 73 8.544 3.9 1.975 19. 4.359 74 8.602 4.0 2.000 19.5 4.416 75 8.660 4.1 2.025 20. 4.472 76 8.718 4.2 2.049 20.5 4.528 77 8.775 4.3 2.074 21 4.583 78 8.832 4.4 2.098 22 4.690 79 8.888 4.5 2.121 23 4.796 80 8.944 4.6 2.145 24 4.899 81 9.000 4.7 2.168 25 5.000 82 9.055 4.8 2.191 26 5.099 83 9.110 4.9 2.214 27 5.196 84 9.165 5.0 2.236 28 5.292 85 9.220 5.2 2.280 29 5.385 86 9.274 5.4 2.324 30 5.477 87 9.327 5.6 2.366 31 5.568 88 9.381 5.8 2.408 32 5.657 89 9.434 6.0 2.449 33 5.745 90 9.487 6.2 2.490 34 5.831 91 9.539 6.4 2.530 35 5.916 92 9.592 6.6 2.569 36 6.000 93 9.644 6.8 2.608 37 6.083 94 9.695 7.0 2.646 38 6.164 95 9.747 7.2 2.683 39 6.245 96 9.798 7.4 2.720 40 6.325 97 9.849 7.6 2.757 41 6.403 98 9.899 7.8 2.793 42 6.481 99 9.950 8.0 2.828 43 6.557 100 10.000 8.2 2.864 44 6.633 313 MEASUREMENT OF WATER Table 65 HOURLY CAPACITIES OF ORIFICES FOR WATER Pressures taken 23^ Diameters Upstream and 8 Diameters Downstream. Capacities expressed in Gallons. Size of Meter is the Diameter of Pipe Line in which Orifice is placed . 50 Inch Differential Chart Orifice Diam. Inches Size of Meter Orifice Diam. Inches Size of Meter 2" 3" 4" 6" 8" 10" Vi 232 227 225 1 1 A 1430 1410 1400 370 358 353 1 1 A 2090 2050 2030 % 550 520 510 IX 2880 2810 2780 7 /i 780 720 700 2 3830 3710 3670 1080 960 930 2Y 2 6300 5900 5800 ly* 1460 1230 1190 3 9700 8800 8500 1M 1960 1570 1480 &A 14500 12500 11800 m 2620 1950 1820 4 21400 17200 15800 IH 3460 2420 2200 &A 31100 233CO 20800 IK 3620 3130 5 31300 26800 2 5370 4320 5^ 42000 34200 * 1 A 7800 5860 6 56000 43000 &A 7900 6^ 55000 2% 10500 7 68000 3 14000 VA 86000 100 Inch Differential Chart Orifice Diam. Inches Size of Meter Orifice Diam. Inches Size of Meter 2" 3" 4" 6" 8" 10" 1 A 328 320 318 1M 2020 2000 2000 Ys 520 510 500 IH 2950 2900 2880 H 780 740 730 i*A 4080 3980 3940 7 /8 1100 1020 990 2 5400 5300 5200 1520 1350 1310 2 1 A 8900 8400 8200 V/8 2070 1750 1680 3 13700 12500 12000 1M 2780 2220 2100 3^ 20500 17700 16700 iy 3700 2770 2570 4 30200 24400 22400 IH 4900 3420 3110 &A 44000 33000 29400 m 5100 4420 5 44300 37000 2 7600 6100 5^ 59000 48000 2^ 11000 8300 6 79000 61000 2y 2 11100 Q 1 A 77000 2% 14900 7 97000 3- 19700 VA 122000 For Minimum Capacity deduct 50 per cent., and for Maximum Capacity add 50 per cent. 314 MEASUREMENT OF WATER WATER COEFFICIENT TESTS In the following tests, a refers to the average value of the coefficient as obtained by the test. The calculated coefficient c, is the coefficient which was obtained by assuming that the "coefficient of velocity" for water was the same as the "coefficient of velocity" for air, the actual internal diameter of pipe being used in all instances. The results of the above tests substantiate the fact that the co- efficient of velocity for air can be used as the coefficient of velocity for water in orifice meter computations. Table 66 Orifice Differ- ential Inches Time vSeconds Quan- tity Gallons Coeffi- cient Remarks Pressures taken 2}/ diameters upstream and 8 diameters downstream 2"x }/ 2 " 34.2 373 31.5 52.0 51. 8a 2"x Y 2 " 44.5 330 31.5 51.6 51. 8c 2"x %" 38.0 148 31.5 124.5 2"x %" 37.0 149 31.5 125.2 2"x %* 36.0 150.5 31.5 125.5 125. Oa 2"x %" 50.0 128.5 31.5 124.7 123. Oc 2"xl" 30.0 85.8 31.5 241.5 242. Oa 2"xl" 20.0 105.5 31.5 240.2 240. 5c 2"xl" 11.0 140.0 31.5 244.0 4"xl" 48.0 666.5 262.3 205. 205. Oa 4"xl' / 35.0 770.0 259.0 205. 207. 2c 4"xlM" 36.0 221.5 253.0 686. 4"xl34" 23.0 271.0 256.5 713. 4"xl%" 41.5 209.0 261.0 698. 700. Oa 4"xlM" 30.5 241.5 260.0 702. 697. 3c 4"xW 42.0 206.5 259.0 697. 4"xl%" 23.0 279.0 261.0 704. Pressures taken at Flange 2"x %" 2"x %" 44.0 32.0 153.0 178.5 31.5 31.5 111.8 112.3 112. la lll.Sc 4"xl" 4"xl" 46.5 48.0 715.5 680.0 262.3 256.5 194. 196. 195. Oa 198. Oc 4"xl%" 4"xl%" 52.0 29.0 212.0 277.0 259.0 255.5 610. 616. 613. Oa 609. Oc 315 MEASUREMENT OF WATER INSTALLING AND TESTING WATER METERS The preceding instructions relative to gas: Measuring Gases and Liquids, Orifice Meter Body, Orifice Meter Flanges, Gauge Line Connections or Taps, Setting up Gauge, Differential Pen Arm, Glass, Adding Mercury, Static Pres- sure Connections, (Pages 239 to 248) apply for measuring water with the following exceptions : In measuring water the installation may be made in any line whether level, inclined or vertical. The main line by-pass and valves may be omitted. By Pass Install by-pass, placing valve at Z. Removing Chart, Clock, Placing Chart, Pens and Ink, Vibrating Pen Arm, and Adjustments (Pages 248-250, 258) These articles apply with the exception that the static spring and pen arm are not necessary for measurement as these liquids are practically incompressible. Starting Gauge Fill gauge with water. Open Z, K and P Open valve W slightly to admit line pressure eliminating air at K and P. Open and close funnel to release all of the air. When all air is eliminated, Close P and K Open W Close Z OpenX Leaks Stop all leaks. Orifice Capacities See Page 298. Same subject, these instructions apply for water as well as for steam. For cap- acities see Page 314. Checking Differential Gauge for Zero Close W and X Open K Open Z The differential pen should return to zero. 316 MEASUREMENT OF WATER The differential pen arm should be kept in a straight line. It can be adjusted to zero by moving slightly at the joint or at the connection with the shaft. When the pen rests at zero, determine if the float is floating and not resting on the bottom of the chamber. See Buoyancy of Float, Page 298. Close Z and K Partially open P Then open X carefully when the differential pen should recede one-fourth inch or more (actual measurement) below the zero line. If the float rests on the bottom of the chamber at zero, add mercury. (See Adding Mercury.) Page 247. After test close P and X OpenZ Checking Differential Pen Arm Close W and X Attach a single column glass tube with a rubber connection and nipple at tap P and fasten tube in a rigid vertical position. Page 301. Open K and Z Open W slightly and admit pressure slowly to expel air from K Mark level of water in glass tube attached to connection at P. Close Z By opening and closing W the reading can be checked with the column of water in the tube above the zero mark. One inch of differential reading on the chart being equal to 0.926 inches of water head in the water column. See Table Page 301. Reading Charts See Page 340. These instructions, relative to Reading Charts, apply to the water measurement. 317 MEASUREMENT OF WATER Zg Diameters Fig. 12550 INCH GAUGE INSTALLATION FOR MEASURING WATER OR LIGHT OILS. FLANGE CONNECTIONS SHOWN DOTTED Fig. 12650 OR 100 INCH GAUGE INSTALLATION FOR MEASURING WATER OR LIGHT OILS. FLANGE CONNECTIONS SHOWN DOTTED 318 PART SEVEN MEASUREMENT OF The Orifice Meter in combination with the Differential Gauge was designed primarily to measure gases under high pressure. During the past few years they have been used successfully for measuring many kinds of liquids, such as gasoline, kerosene, crude oil, and reduced Mexican crude oil. The type of meter and gauge used for measuring oil is identical with that used for measuring gas or air, with the exception that the static pressure spring may be omitted as water and oil are practically incompressible. The same types of charts are used, reducing to a minimum the various styles and amounts of supplies required, not to mention the decrease of maintenance and inspection. The operator needs to be familiar with only one type of meter and the office work is greatly simplified as only one kind of chart is to be read. The meter is installed in the same manner as for measur- ing gas. Simply place an orifice in an orifice meter body or between two flanges in an existing line, making two small pipe pressure connections leading from the pipe line, one on each side of the orifice, to the differential gauge. The gauge may be installed at any location convenient for observation and inspection. For each installation the orifice, in the orifice disc, when placed in the pipe line, forms a definite section of unchanging area, and creates a definite difference between the static 319 MEASUREMENT OF OIL pressure of the fluid on the upstream side of the orifice, arid the static pressure of the fluid on the downstream side of the orifice, for each velocity or rate of flow of the fluid, at the same density. This difference in static pressures is termed the differential pressure or the "differential." In other words the "differential," in cases of liquids, indicates the velocity. The Differential Gauge records on a chart the differential pressure existing between the pressure connections. This factor with the known area of the orifice enables us to de- termine the flow of liquids from the formula : Q = C VT Where () = the Quantity of liquid passing the orifice. The result can be expressed in "gallons" or "barrels" per hour. C = the Hourly Coefficient. The value of this term remains the same for each installation and basis of measurement. h = the Differential Pressure existing between the two pressure connections, expressed in inches of water head, this value is recorded graphi- cally on the chart of the Recording Dif- ferential Gauge. The value of the Hourly Orifice Coefficient C in the above formula is found on Page 330, computed for various diameters of orifice and diameters of pipe, these values having been determined by exhaustive experimental and practical tests in comparison with actual displacement. The extensions of the values of V h have been compiled and are given in Table 64 Page 313. Example One hour reading: Average differential reading h = 25 inches. Diameter of Pipe = 4 inches. Diameter of Orifice = 2 inches. 320 MEASUREMENT OF OIL 321 MEASUREMENT OF OIL When oil is measured (using the above data with Gravity 30 deg. Baume) the Hourly Orifice Coefficient C is 24.64 of a 2 inch orifice in a 4 inch line, (Table 67, Page 330). Orifice Pressure (2-24.64 V25 -24.64 X 5.000 Coefficient Extension or the quantity passing through the orifice = 123.2 barrels per hour. Therefore the quantity per hour flowing in the line is equal to the Orifice Coefficient multiplied by the Differential. The relation between the differential and the velocity of the fluid through the orifice is expressed by the formula : Where V = velocity of flowing fluid in feet per second. g = acceleration due to gravity in feet per sec., per sec. = 32.16. H differential expressed in feet head of flowing fluid. _ The well known formula V= V2 gH expresses the theoret- ical flow, eliminating friction and other influences. When applied to actual conditions a correcting factor is used to take care of influences due to contraction of jet, friction, etc. This correcting factor C v is commonly known as the "co- efficient of velocity." In this formula the differential head is expressed in feet head of flowing fluid ; and as it is not practical except in case of water to register this value directly, the differential is recorded on the chart in inches of water pressure. If oil of 30 deg. Baume is flowing in a line, the theoretical differential would be expressed in feet head of oil. The specific gravity of this oil is 0.875 therefore 0.875 feet or lO^ inches of water would-be equivalent to one foot of oil. One inch of water equals 1/10.5 or 0.09525 feet of oil. Twenty inches of water would equal 20 times 0.09525 feet or 1.905 feet head of oil at 30 degrees. 322 MEASUREMENT OF OIL h Where #=- differential in feet head of flowing fluid. h = differential in inches of water pressure. 12 = number of inches in a foot. p = specific gravity of flowing fluid (water = 1.000) The above example would be written thus: 90 12 X 0.875 = 1.905 feet of head oil. Substituting the value of H in the formula V = C v V 2gH We obtain V = C V -- = C v 2 X 32.16 12p 12p 7 = 2.3152 C v ^ p This expression illustrates the fact that the velocity de- pends upon the specific gravity of the liquid. As the specific gravity increases, the velocity decreases when the differential pressure is a constant. Or using a plain illustration with the same force applied, a cubic foot of hot tar will move with less speed or velocity than the same quantity of gasoline. In measuring light or heavy oils with an orifice meter the connecting lines and the gauge itself are filled with water or oil and thus the heads of liquid acting on each portion of the gauge are equal. Due to the fact that the recording gauges are filled with liquid each inch of mercury differential is partially counter- balanced by an inch of liquid. Each inch of mercury dif- ferential is equivalent to only (13.6-p g ) inches of water differential instead of 13.6 inches which would be the case if the liquid did not fill the gauge and connections. 323 MEASUREMENT OF OIL Where 13. 6 = specific gravity of mercury. p g = specific gravity of liquid in gauge. 13.6-/ Therefore, the differential h is multiplied bv the factor 13.6 for the reason that differential gauges are constructed to indicate 13.6 inches of water pressure differential for each inch of mercury differential. Substituting these factors in 7 = 2.3152 C we obtain 7 = 2.3152 13.6 p The quantity of fluid passing the orifice in gallons per hour is equal to the area. of the orifice in square inches multi- plied by the velocity in inches per hour divided by 231. This fact may be expressed by the following formula : 0.7854 2 231 Q= 146.88 d 2 X V Where Q = quantity of fluid passing the orifice in gallons per hour. 0.7854 d 2 = area of orifice in square inches. d = diameter of orifice in inches. 231= number of cubic inches in a gallon. 3600 = seconds in one hour. y = velocity of fluid through orifice in feet per sec. 12 = number of inches in a foot. 324 MEASUREMENT OF OIL 325 MEASUREMENT OF OIL MEASUREMENT OF OIL Substituting the value of V where 7=2.3152 C v in this expression. Q= 146.88 d 2 X 2.3152 C v -J (1 ^? g)/? ' lo.u p 13.6 P It has been found that the simple layout shown on Page 318 can be used very satisfactorily for measuring light oils or oils of low viscosity. For heavy oils, reservoirs (Figs. 131 and 132) made of a 12 inch length of 4 or 6 inch pipe and two caps, are installed on each gauge line. These reservoirs are installed vertically on the same level. The reservoirs and gauge are filled with water. When oil is admitted to the reservoirs from the main and when the gauge is open, the air in the gauge lines and gauge will be displaced by the water. The excess water be- ing released by valves RR. Figs. 131 and 132, so that the water occupies about one half of the height of the reservoir. When the by-pass lines are open and a flow does not exist through the orifice, the surface of the water will seek the same level and the pressure head of the liquids in the gauge lines and gauge will be equal. When a flow exists and the differen- tial h increases, the water level at S is lowered and at T is raised, (Fig. 130) causing a portion of the oil to flow through the connection into the main at D. In the mean- time additional oil is filling the reservoir S. .Orifice mcerSea/or. Fig, 130 DIAGRAM OF ORIFICE METER INSTALLATION FOR MEASURING HEAVY OIL 327 MEASUREMENT OF OIL When the oil is measured without the installation of water seals, the oil occupies the gauge lines and gauge itself. In this case p g and p are equal to the specific gravity of the oil being measured. Table 67 was prepared, using as a basis, oil of 30 deg. Baume or specific gravity .875. The previous formulae give results in gallons per hour. To express the quantity in barrels of 42 gallons per hour, of oil of 30 deg. B., the formula Q = 340.06 C, d . becomes * 13. 6p 340.06 C v d 2 [(13.6-.875) h 42 ^ 13.6X.875 Q-8.3728 C v d 2 VT~ where Q = quantity in barrels of 42 gallons per hour. The Hourly Coefficient C in Table 67 is equal to 8.3728 C v d 2 . The various multipliers shown in Table 68 were determined by using various values of specific gravities of liquids for p g and p in the formula and take into account the difference in water levels occurring in various sizes of reservoirs due to displacement above and below the zero level occasioned by the volume of mercury displaced in the gauge. See following example (Page 329) for use of multipliers. Investigations and tests have shown that the coefficient of velocity C v for water and oils whose viscosity is less than water is practically the same as for gas, air, or steam. The compiled data of some of the tests given on Pages 333 and 334, indicate that there is no substantial difference. In computing the Tables of Hourly Orifice Coefficients, the values of C V) determined for air, have been used. 328 MEASUREMENT OF OIL The values of C, the Hourly Orifice Coefficient, for oil of 30 deg. B. are given in Table 67 on Page 330. These Coefficients are prepared for pipe of standard dimensions (2.067, 3.088, 4.026, 6.065, 8.071 and 10.191 inches internal diameter). Coefficients for pipes of other internal diameters for various sizes of orifices can be determined as follows. Example Oil being measured. 40 deg. Baume. Vis- cosity, 40 seconds Saybolt. Water seals, 6 inches in diameter, 50 inch gauge. Internal Diameter of Pipe = 3. 548 inches. Diameter of Orifice = 2J< inches. 2 2^0 Ratio ^ = ^^=.6342 3.548 C v for ratio .6342 = .877 (Page 210). Coefficient- 8.3728 C v d 2 . = 8.3728 X .877 X 2.25 X 2.25 = 37.17 barrels per hour for 30 deg. Baume without reservoirs. Revision for Coefficient from 30 deg. Baume to 40 deg. Baume including revision on account of water seals and range of gauge (Table 68) = 1.027. Revision for viscosity (Table 69) = 1.020. Coefficient for above conditions = 37. 17X1. 027 XI. 020 = 38.93. 329 MEASUREMENT OF OIL Table 67 HOURLY COEFFICIENTS FOR OIL Pressures taken 2^ diameters upstream and 8 diameters downstream. Values of C in Q = C V h where Q expresses the quantity of oil or other liquids in Barre's (42 gallons) having a density of 30 deg. Baume, passing through the orifice per hour. Size of meter is the diameter of pipe line in which orifice is placed. Diam. of DIAMETER OF PIPE LINE unnce Inches 2" 3" 4" 6" 8" 10" " % Y* W w 1% 1H 1% 1% iy 8 2 2y s ak 1.322 2.108 3.123 4.420 6.080 8.217 10.98 14.57 19.24 1.296 2.046 2.977 4.106 5.451 7.043 8.918 11.13 13.75 16.85 20.54 24.94 30.18 36.43 43 90 1.285 2.022 2.933 4.023 5.299 6.773 8.461 10.38 12.56 15.03 17.84 21.02 24.64 28.76 33 46 2^890 5' 188 8"l86 11. '92 16 '44 21. 84 28 24 5^138 8*086 11.73 16'09 21. 19 27 08 8.026 11 '63 15*91 20.90 26 62 2^ 2 1 A 2^8 38.83 44.97 52 00 35.79 33' 83 33.09 2^ 2% 3 3M 3H 60.05 69.23 79.76 44.73 55 '31 67.89 ' 82 88 41.51 50 '22 60.09 71 28 40.34 48 A3 57.40 67 32 3% 100 8 83 99 78 31 4 122 2 98 42 90 43 4M 147 8 114 9 103 8 41% 178 4 133 6 118 6 *\* \^\^>\^ XCO\ .-(\r-i\CO\ Tj< 10 10 LO 10 < 155.0 179.5 207.5 239.5 276.2 317 9 134.9 153.0 173.1 195.3 220.0 247 5 Q l /i 278 QY 2 311.8 6% 7 7 1 4 349.6 391.6 438 2 7y 2 490.0 See Tables 68 and 69 for Multipliers for Specific Gravity and Viscosity. 330 MEASUREMENT OF OIL Table 68 MULTIPLIERS FOR HOURLY COEFFICIENTS FOR OIL FOR VARIOUS SPECIFIC GRAVITIES OF OIL WHEN USING WATER SEALS OR RESERVOIRS OF VARIOUS SIZES. USED WITH TABLE 67 50" 100" Reser- Gravity gauge gauge 50" 100" 50" 100" voirs of Oil Degrees 2H"res. or no lM"res. or no gauge ga^uge gauge gauge 6" unlim- ited Baume res. res. res. res. res. res. Area 10 .931 .931 .931 .931 .931 .931 .931 20 .966 .966 .965 .964 .964 .964 .964 30 1.000 1.000 .997 .996 .996 .996 .995 40 1.033 1.033 1.029 1.027 .027 1.026 1.026 50 1.065 1.065 1.059 1.057 .057 1.056 1.055 60 1.096 1.096 1.089 1.087 .086 1.085 1.084 70 1.126 1.126 1.118 1.115 .114 1.113 1.112 80 1.155 1.155 1.146 1.143 .142 1.141 1.140 90 1.184 1.184 1.173 1.170 .169 1.168 1.167 100 1.211 1.211 1.200 1.197 1.196 1.195 1.193 Minimum distance 8" 12" 6" 6" 4" 4" 2" between connect'ns The reservoirs made of pipe are installed vertically. The minimum distance mentioned is between the inlet con- nections and outlet connections of the reservoirs. Table 69 MULTIPLIERS FOR HOURLY ORIFICE COEFFICIENTS FOR OIL FOR VISCOSITY USED WITH TABLE 67 Viscosity Saybolt Seconds Multipliers Viscosity Saybolt Seconds Multipliers 40 50 60 70 80 100 1.020 1.035 1.045 1.052 1.058 1.066 150 200 300 500 700 1000 1.080 1.092 1.107 1.126 1.140 1.150 331 MEASUREMENT OF OIL Table 70 HOURLY CAPACITIES OF ORIFICES FOR OIL Pressures taken 2> Diameters Upstream and 8 Diameters Downstream. Capacities expressed in Barrels of 42 Gallons. Size of Meter is the Diameter of Pipe Line in which Orifice is placed. 50 Inch Differential Chart Diam. Orifice Inches Size of Meter Diam. Orifice Inches Size of Meter 2" 3" 4" 6" 8" 10" I A 5.9 5.8 5.8 1M 37 36 36 *A 9.5 9.2 9.0 IX 53 52 52 H 14.1 13.3 13.1 m 74 72 71 % 19.9 18.4 18.0 2 98 95 94 i 27.5 24.5 23.8 2 1 A 160 152 148 ly* 37.4 31.7 30.4 3 248 225 217 Vi 50.2 40.1 38.0 3^ 371 319 302 i*A 67.0 50.0 46.6 4 546 440 405 1M 88.5 61.9 56.3 4^ 796 597 531 1% 92.9 79.9 5 802 685 2 137 110 5^ 1070 873 *y 199 150 6 1420 1110 2y> 201 6U 1390 *" S & &A 268 Vf / Z 7 1750 3 357 7^ 2190 100 Inch Differential Chart Diam. Orifice Inches Size of Meter Diam. Orifice Inches Size of Meter 2" 3" 4" 6" 8" 10" 1 A 8.4 8.2 8.2 1M 52 51 51 5 A 13.4 13.0 12.8 1M 76 74 74 y 19.9 18.9 18.5 IK 104 102 101 % 28.2 26.1 25.4 2 138 134 132 38.9 34.7 33.6 2y 2 227 214 210 1 1 A 53 45 43 3 350 318 307 1 1 A 71 57 54 3^ 525 452 427 l*A 95 71 66 4 773 623 573 l l /2 125 88 80 4^ 1126 845 751 1% 131 113 5 1134 969 2 194 156 5^ 1520 1240 2M 281 212 6 2010 1570 2*4 284 6*/ 1970 ** / i 2% 380 7 2480 3 505 7y 2 3100 For Minimum Capacity deduct 50 per cent. Capacity add 50 per cent. 332 and for Maximum MEASUREMENT OF OIL TESTS MEASUREMENT OF OIL Following is a summary of tests conducted for measure- ment of various grades of oils by orifice meter. Table 71 Num- ber of Tests Grade Line Size Av. Time Tests (hrs.) Total Quan- tity (bbls.) Viscos- ity Factor Aver- age Devia- tion 07 Devia- tion of Total /c 4 Kerosene Dis. 8" 2.2 2,800 1.000 1.0 +0.7% 2 Caddo Crude 10" 10.0 18,700 1.000 2.2 +0.7% 2 Coastal Crude 8" 10.0 9,600 1.050 0.2 +0.2% 11 Mex. Crude 10" 5.9 49,500 1.146 2.3 +2.0% 26 Reduced Mex- f 1.118] ican Crude 3" 0.3 475 \ to 2.5 -0.9% [1 . 144J The results indicate that for oils having a viscosity equal to or less than water, the coefficients of velocity derived for air flow can be used by applying a factor for gravity only, and when oils have a viscosity greater than water the vis- cosity factor must also be applied. The above series of tests was conducted for the purpose of determining whether the viscosity of oil or liquids would require the use of a coefficient or multiplier for liquids of various viscosities. The preliminary tests conducted on Reduced Mexican Crude indicated that such a correction factor or multiplier was necessary. In order to determine whether a multiplier was necessary for oils whose viscosity was equal to or less than water, tests were first conducted on Kerosene Dis- tillate (the viscosity of which is less than water) which indicated that a multiplier was not required. A like result was obtained in measurement of Caddo Crude. However, 333 MEASUREMENT OF OIL in case of Coastal Crude it was found that the orifice meter measurement gave results approximately 5 per cent less than tank measurement when the multiplier was not used. In the case of the Mexican Crude and Reduced Mexican Crude, greater deviations were obtained. These deviations for in- dividual tests were plotted on a logarithmic diagram against the kinematic viscosity of the oil in question. It was found that these deviations did not vary appreciably from a mean curve drawn through the results. From this curve a multiplier was determined for use with oils of varying vis- cosities which multiplier or factor was afterwards applied to the results with the deviations as shown above. In order to determine the effect of pumps on lines and relative effect due to location of pumps, approximately one- half of the tests were conducted when the flow through the line was due to gravity only, and in other cases the flow was produced by pumps at various distances from the meter, in some cases being only 10 feet away from the meter. However, in all of these cases the pumps were double acting and made only about 40 revolutions per minute. The re- sults obtained by gravity and those obtained when pumps were used, were similar. There was no evidence of any de- viation which could be attributed to the pumps. However, in the measurement of gas or any liquid it is not possible to measure a flowing liquid where pulsations are produced through the orifice by quick acting pumps. In addition to the above tests, extensive tests covering a period of a month or more were made in which several hun- dred thousand barrels of Coastal Crude Oil were measured, the results of which checked with tank measurement within 3/10 of a per cent and at the same time tests were conducted using the orifice meter for measurement of reduced Mexican Crude Oil in which the percentage deviation between tank measurement and meter measurement was varied from 3/10 of a per cent to 1^ per cent measuring 3800 barrels of oil. 334 MEASUREMENT OF OIL INSTALLING AND TESTING OIL METERS See Figures on Pages 318 and 339. To successfully measure oil it is necessary to eliminate violent, pulsation and vibration from pumps by means of air chambers or by placing the meter as far away from pumps as possible. The preceding instructions relative to gas: Measuring Gases and Liquids, Orifice Meter Body, Orifice Meter Flanges, Gauge Line Connections or Taps, Setting up Gauge, Differential Pen Arm, Glass, Adding Mercury, Static Pressure Connections, (Pages 239 to 248) apply for measuring oil with the following exceptions: In measuring oil the installation may be made in any line whether level, inclined or vertical. The main line by-pass and valves may be omitted. In measuring heavy oil it is desirable to pre- vent the oil from entering the gauge or coming in contact with the mercury. The use of water reservoirs or seals eliminate this possibility. Figure 130 shows diagram- atically, oil installations, one where the oil line is above the gauge and the other where it is below. The reservoirs Figs. 131 and 132 should contain valves or plugs in the top for releasing the air when they are being filled with water (Page 339). The valves RR are placed at the middle point in the vertical height of the reservoirs and on a level with each other for purposes of determining the height of water in the reservoirs when the installation is ready to be placed in operation. Ordinary visible water gauges and glasses may be used in place of valves RR to indicate the level of the water in the reservoirs. The connections or pipe lines from the upstream and downstream connections to the reservoirs and the oil by-pass between the reservoirs, are % inch pipe. This oil by-pass is installed so that the head of water in the reservoirs can be leveled by opening valves B and Z when valves W and X are closed. If the head of 335 MEASUREMENT OF OIL water is higher in one reservoir than in the other, the dif- ferential reading will be affected due to the difference in densities of the water and oil. In measuring light refined oils use the simple layouts shown on Page 318. By Pass Install by-pass, placing valve at Z. Removing Chart, Clock, Placing Chart, Pens and Ink, Vibrating Pen Arm, and Adjustments (Pages 248, 249, 250 and 258) These articles apply with the exception that the static spring and pen arm are not necessary as the liquids are practically incompressible. Starting Gauge Fill gauge and reservoirs with water. (In measuring light oils omit reference to reservoirs and valve B, when using layouts, Page 318) Open B, Z, K and P Open valve W slightly to admit line pressure eliminating air at K and P. When all of air is eliminated. Open and close funnel to release air. Close P and K Open W Open RR until oil flows from each valve, or if visible gauge glasses are used release the water from the petcock from the lower gauge cock until the oil occupies the upper half of the reservoir, then close the valves or petcocks. Close B and Z OpenX Leaks Stop all leaks. Orifice Capacities See Page 298. For capacities see Page 332. 336 MEASUREMENT OF OIL Checking Differential Gauge for Zero Close W and X OpenK Open Z The differential pen should return to zero. The differential pen arm should be kept in a straight line. It can be adjusted to zero by moving slightly at the joint or at the connection with the shaft. When the pen rests at zero, determine if the float is floating and not resting on the bot- tom of the chamber. (See Page 247). Close Z and K Partially open P Then open X carefully when the differential pen should recede one-fourth inch or more (actual measurement) below the zero line. If the float rests on the bottom of the chamber at zero, add mercury. (See Page 247). After test close P and X and Open Z Checking Differential Pen Arm (In measuring light oils omit reference to valve B, when using layouts, Page 318) Close W and X Attach a single column glass tube with a rubber connection and nipple at tap P and fasten tube in a rigid vertical position. (Page 301). Open K, Z and B Open W slightly and admit pressure slowly to expel air from K Mark level of water in glass tube attached to connection at P when water seals are used. Close B and Z 337 MEASUREMENT OF OIL By opening and closing W the reading can be checked with the column of water in the tube above the zero mark. One inch of differential reading on the chart is equal to 0.926 inches of water head above the zero mark in the water column. This statement applies when water seals or reservoirs are used. (See Table, Page 301). When using the layouts for measuring light oils, Page 318, the light oil will fill the glass tubing. The height that it rises above the zero setting for a certain chart reading will be equal to the water reading revised for the gravity of the oil according to the following Table. Table 72 CHECK READINGS ON LIQUID COLUMN IN INCHES OF LIQUID Be. Reading on Chart Be. Reading on Chart Grav- Grav- ity 10" 30" 50" 100" ity 10" 30" 50" 100" 30 10.7 32.0 53.4 106.9 65 13.2 39.6 66.0 131.9 35 11.0 33.1 55.2 110.5 70 13.5 40.6 67.7 135.5 40 11.4 34.2 57.0 114.1 75 13.9 41.7 69.5 139.1 45 11.8 35.3 58.8 117.7 80 14.3 42.8 71.3 142.7 50 12.1 36.4 60.6 121.2 85 14.6 43.9 73.1 146.2 55 12.5 37.4 62.4 124.8 90 15.0 44.9 74.9 149.8 60 12.8 38.5 64.2 128.4 95 15.3 46.0 76.7 153.4 In the latter case the oil may be removed from the gauge and it may be tested by filling the gauge with water, by closing W, X, and Z, opening K and adding water through the glass tubing. In this case use Table, Page 301. 338 MEASUREMENT OF OIL Fig. 13150 INCH GAUGE INSTALLATION FOR MEASURING OIL Fig. 13250 OR 100 INCH GAUGE INSTALLATION FOR MEASURING OIL 339 MEASUREMENT OF OIL READING CHARTS The formula for use of the orifice meter is : Quantity of liquid per hour = Coefficient X V h , in which h = differential pressure in inches of water. To obtain quantity, average the differential pressure for each hour of the day. Obtain values of V h (differential pressure extensions) for each hour. Add these extensions together and multiply the sum by the coefficient for the orifice being used. The product will be the quantity of oil or water passing through the meter for the period during which the differential pressure is averaged. See Page 313 for a table of Differential Pressure Extensions, (values of V h , 1 to 100 inches). See Page 268, Orifice Meter Calculator. 'JVT: ORIFICE METER CHART REPORT,. STATION JfasYLrt* 1 ^ DATE Ho. A-'. Differential Extension TIME Inches Water 12 - 1 a 1 - 2 a 2 - 3 a 3 - 4 a 4 - 5 a ,9 ** C TOTAL . Coeff. DELIVERY Fig. 133 ORIFICE METER CHART REPORT FOR A PERIOD OF 5 HOURS 340 PART EIGHT ORIFICE CAPACITIES The following Tables of Hourly Capacities of Orifices give the approximate capacities for orifices at various dif- ferentials, each Table for a certain line pressure. They are based on specific gravity .6, pressure base 4 oz., base and flowing temperature 60 deg. fahr., atmospheric pressure 14.4, and are prepared for ten different pressures and four sizes of line,- 40 tables for pressures taken at the flange and 40 for 23/2 and 8 diameter connections. The capacities for pres- sures taken at the flange apply where the static pressure is obtained on the downstream side of the orifice. Referring to Table 104 for 10 inch line, pressure lb., the capacity of 2^ inch orifice at pressure, 1 inch differen- tial is 8000 cubic feet per hour. If this size of orifice is being used in connection with a 50 inch gauge, an average reading of 1 inch is entirely too small. If the pressure remains the same it is advisable to obtain a reading at least 4 inches or greater on a 50 inch gauge at this volume of flow. A 2 inch orifice has a capacity of 8300 feet an hour at 4 inches differen- tial, a 1% inch orifice would produce a differential of greater than 6 inches and a 1^ inch orifice a differential of between 10 inches and 15 inches. These Tables serve to indicate a proper size of orifice required to obtain a certain average differential for a certain hourly flow. The relative capacities of ori- fices where the line pressure will be approximately the same before and after changing the orifice, can be determined by using any table for the same size of line. If the pressure is 40 lb. per square inch, the 2% inch orifice in a 10 inch line at 2 inches differential will have the same capacity as l 1 /^ inch orifice in a 10 inch line at 50 inches differential. 341 ORIFICE CAPACITIES If the hourly rate of flow is approximately 80,000 cu. ft. per hour for a 4 inch orifice in a 10 inch line, at average dif- ferential reading of about 20 inches at zero pressure and it is desired to reduce the Jlow to 20,000 feet per hour and still obtain the approximate average of 20 inches differential. By following the capacities opposite a 20 inch differential to the right, (Table 104) it is seen that the 2 inch orifice has a capacity of 18,600 cubic feet per hour at zero pressure and 20 inches differential. A 2^ inch orifice has a capacity of 23,700 cubic feet per hour at pressure and 20 inches differential. Use the 2 or 2J4, preferably a 2 J/g inch. It is shown that if the same size of orifice is used, for instance, the 4 inch orifice at 20 inches differential for measuring 80,000 feet per hour the average differential for 20,000 feet per hour would be less than 1 J'2 inches which is entirely too low a differential for a 50 inch gauge. The Tables also show that a gauge with a maximum dif- ferential of 10 inches has 45 per cent of the maximum cap- acity of a 50 inch gauge and that a 20 inch gauge has 63 per cent of the capacity of a 50 inch gauge. The maximum range of gauge to be used can be determined very quickly by inspection of a table showing the line pressure and size of line. Although these tables are prepared on a pressure base of 4 oz. and specific gravity of .6, they may be used as above indicated by remembering that the relative capacities of various orifices for various differentials are the same re- gardless of pressure base and specific gravity. If the specific gravity is 1.5, pressure base 3 lb., it is still true that a 4 inch orifice in a 10 inch line at 1 inch differential will have approximately the same capacity as a 1% inch orifice in a 10 inch line at 40 inches differential. These tables will eliminate delays in making calculations to determine the proper size of orifice to be used where orifices are to be changed on ac- count of change of flow, change of pressure and excessively low or high differentials. 342 ORIFICE CAPACITIES The following table gives the multipliers for revision of the Capacity Tables for Pressure Base and Specific Gravity. Table 73 MULTIPLIERS FOR REVISION OF ORIFICE CAPACITY TABLES FOR GAS FOR SPECIFIC GRAVITY AND PRESSURE BASE SPECIFIC GRAVITY Pressure Base .60 .70 .80 .90 1.00 1.10 1.20 1.30 1.40 oz. . 1.02 .94 .88 .83 .79 .75 .72 .69 .67 4 oz. 1.00 .93 .87 .82 .78 .74 .71 .68 .66 8 oz. .98 .91 .85 .80 .76 .73 .70 .67 .64 10 oz. .97 .90 .84 .80 .76 .72 .69 .66 .64 1 Ib. .95 .88 .82 .78 .74 .70 .67 .65 .62 l^lb. .92 .85 .80 .75 .71 .68 .65 .63 .60 2 Ib. .89 .83 .77 .73 .69 .66 .63 .61 .59 3 Ib. .84 .78 .73 .69 .65 .62 .59 .57 .55 Fig. 134 343 ORIFICE CAPACITIES FOR GAS 00 O CM rH b- kO CO t> 00 i-H CM CO CM O I-H CM rH OS kO kO kO kO OS CM b- 00 OS O CM rH l> rH CM i 1 rH |: CM 00 CO rH CO CO rH kd CO CO kO 00 J> J> 00 OS O i-H O t> OS 00 CM rH CO O rH rH rH CM O rH OS OS rH OS CO t- CM CM CO CO kO CO rH CO CO kO rH kO CO t- 00 i-J 5 %T. 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CO O rH CM CO CM CO rH CM Tf lO rH i 1'rH rH t- TX 10 CO i> 1> lO O5 CM CO O5 O CM rH i 1 . rH CM TX rH rH O5 rH CO CO rt rH rH lO b- CM CO 00 CM CO O5 rH CM CM CM O5 lO lO rH rH O5 CO ^ lO lO ^ rH l> CM lO CO CO 00 05 rH TX 10 o co, CO CO O5 rH rH rH rH CM O rH 00 lO CO O CO CM CM CO CO ^f lO 1> CM O t> rf lO CO CO rH t> CO 10 O rf< id co od CM CO O 10 05 rH CO TX i-H rH rH CO CO CM rH i> d id 05 rH CM CM CM lO CO rH C55 CM LO rH CO CO CO T^ Ti< rH 05 CO rH O CM CO TX id 00 rH CM CM lO t- 00 O5 CM O 05 CO J CO lO CO rH i-H i-H rH LO lO O5 rH O CM lO O5 CM CM CM CM X CO O rH CO CO O CO 00 rH CM CM CM t- o o CM O CO CM CO 'tf TH lO CO CO O CO CO > 05 O CO J> CO CO rH CM rj< CO rH rH i-H rH Differential in Inches of Water 10 rH i-i CM CO TX co co o r 1 lO O O O rHCMCO^ O O O O lO CO 00 O rH 359 ORIFICE CAPACITIES FOR GAS 9 8 , OT tn * co t: B CC C^ s s W ^ a CO $ O5 t- O5 > i-H Tf CD O rH rH r-l CM O CO O5 O5 r}< O5 00 t- CM CM CO CO CO ^f CO CO ^J< LO CO t- o o o o LO OO t- O5 00 O5 O i I i-H i 1 * i-H i 1 i 1 LO CM CO I-H 2 CM CM O5 O5 1 O I-H CO LO CM CO CO ^ LO d d d d 00 ^ ^ CM LO CO t> 00 CO CO 00 00 CO lO CO i> O5 i-H CO t> CO r-H 00 LO t- 10 00 *' r-! I -^ O LO CM CM CO CO CM d co d O5 CO O5 CO CO l> CO CO ri< CO ^ LO CD rj< rH LO 00 t~ 05 O --H r 1 I 1 ^ so O LO T^ CO T^ CO ^H ^H CM CM 00 00 CO CM CD 00 CO t^ CM CM 00 CO 1> O5 CD i 1 CD CM CO rj< -^ Lb CD 00 05 ^ Tj< CM t> O I-H CO -^ i-H i-H i-H il r i O CO t> CM i 1 00 LO O5 (M CM -^ i l CM t> i l >O CM CM 00 00 o co 00 O5 i-H O -tf T^ CO t- 00 CD O5 O i> 00 05 rH rH O Z> CO 00 O lO CO CM 05 J> 00 i i 00 05 rH 00 i-H i 1 S2! o LO co o CO CO "* LO CO CM rH O LO CO I> 00 i-H LO J> 00 LO LO CO t- O5 o LO co rj< i i CO LO i> CO CO .-H 00 CM 'CM CO CO O5 CD CM 00 CM 05 LO CO ^ ^ LO i-H to co 05 o CO ^ ^ CO O LO 00 O 1> 00 05 nH i-H LO CO ^-1 O 00 LO O5 CM rH rH ^H CM CO O i-H O5 CM CM CO 00 ^ LO O5 CO 00 O5 CO *- CO -H CM CM CO O 00 O5 J> LO CM CO -^ O CD CO t> t> 00 i> 00 O CM 00 l ^ LO CO LO t> 05 Differential in Inches of Water LO .-H i-H CM CO "tf CO 00 O 1 1 LO O O I-H (53 co -^ O O O LO CO 00 O 360 ORIFICE CAPACITIES FOR GAS w s I a< 1 3. o: 55 S I S H "" ' 5 ,O HH c s eii O s^ s " ^ si] S a g S H '5 w ^ 1 r-^ ^ a 5 s ^ H ^ w 1 o CD \ OO CO OS CO rH rH rH CM T^ LQ t- CO 1> CO 00 CO CM CO CO -^ 000 i-H kO t> CO i> 00 t~ CO CM t OS O CM CO ^ assg'i t~' os' 10 co CO CM CO OS r-n CM CM CM CO OS O O CO Tf to lO CO CO LO ^ \M CO s'g'ss rH CM LO O i ( i l r i CM lill LO OS t- T^ T^ T^< lO CO CO g'ss'g 10 - CO GO l> CM CO CO <* lbB5 O CM O t- r t i-H i-H rH ^ 00 CO LO OS rH Tj< f- rH CM CM CM o ^ 'o w t- t> CO 00 rH CO O i> CM CM CO CO co CO CO CM OS tf 10 CO CO Sol2^ ** OS LO t> LO CO OS rH OJ 1 - rt 00 CO 00 -H CO O CO OS H CM CM CM- CO rH 1C CO rH b- 00 00 Tt< rj< lO s^g rH 2SSS rH rH rH rH - X rH CO ^ 00 00 CM kQ'C- i 1 l-H r-t rH CM CM OS CO CO LO O O OS CM CO CO CO 00 CO CO OS O Tt< iO CO 00 OS 00 CO CO 00 OS rH CM S CM CM O 05 OS r- ( CO LO ^ 10 O O 2^8 CO rH lO rH O 00 00 Tt< LO lO cS^S8oi ^ rH 00 t> OS OS co t> 06 d CO Tf 00 t> CM to t- OS ^ CM lO CO CM CM CO CO CO CO ^ CO CO CO ^ r^ LO co rH 00 OS OS 00 CO OS CO -^ LO CO O CM CO CO 00 OS i CM i 1 i l ^ 00 OS CM lO t- rH LO rH rH CM CM CM OS t- 00 06 d LO os CM CO 00 CO ^ CO TM t- 00 CM b- i I 00 CM CM 00 CO 00 ^ lO 00 rH Tji lO CO > i> O CO CM CO O CM Tji rH rH rH co ^ o oo SrH^ Differential in Inches of Water LO i 1 i 1 CM CO TX CO 00 O i-H Sg^^ S CO CO O rH 361 ORIFICE CAPACITIES FOR GAS CrO 3 ** wig gift 5 PH <" CO a B'lJI s ^ s .2 o: d w CM O J I a -M S - c "I i *s C^ ^ "o es wj SJ|I o s s g b S3 O H^ W ^^ il > 2 5 o s ^ m w 1 O $ tO CM 00 CO CO O 00 CO rH CM CM CM O Tf t> O 00 O CO CM oo Tf Tf to CO > O5 O O O O O t- 00 00 10 rH CM Tf CO " rH rH rH rH CO O5 CM rH CM CM 00 00 Tf rH CM CM rj< tO CO C- rH CO CM Tf 00 00 O rH rH rH 00 S8 lO 00 rH Tf CM CM CM CM 00 rj< CM t- 05 Tf< CM 00 CM 00 -tf rj< 111 00 lO CO t> 00 00 CD CD OO 1 O5 O CM CO Oi OO CO CM rH CM CM 00 Ilil 4) co\ ^ CM CM rH 05 CM Tf tO tO t SooSoo rH CO 00 00 OiCMt^S O CM CM CM 00 00 Tf M 00 00 rH 00 CO Tf Tf tO CO 00 O5 O rH 83S83 rH rH rH CM tO Oi 00 00 00 tO O5 00 CM CM CM 00 00 CM rH IO O \^ s N %%&% asss CM t> Tj< CO O rH T^ CO CO 00 tO 00 CO O 00 CD rH CM CM CM Oi rH CM Tf Sooo CM M CO t CO IO 10 CO rH CO rH rH CM CM CO tO 00 Tf O t- 00 00 00 00 Tf Tf Oi 00 Tf J> tO CO 00 Oi co' oi t> oo O rH 00 tO \w rH O tO CO rH rH 00 tO 05 rH rH rH rH O 05 ,rH 00 CM CM CO CO CO CM CM Oi O O rf Tf CD t rH CO 00 00 CM CO fc- CO rH CO rH 00 00 rH t- 05 O 00 rH rH IO 00 rH Tf rH rH CM CM CM OO Tf ^ Tf Oi 00 CD to tO CD t- rH 00 O5 CO OO Tf lO CO 00 CO 00 CO CM Oi rH 00 lO CO tO 00 Tf 00 rH CD O rH CM CM 00 Oi CM Oi CM X t- 00 00 CD CM CO CO Tf 00 CO CO IO td CO 1> CO tO rH 00 rH O CM Tf t-" rH rH rH rH rH Oi rH O Oi O Tf l> rH CM CM CM Differential in Inches of Water tO rH rH CM CO ^ co oo o rH S88S 88 rH 362 ORIFICE CAPACITIES FOR GAS 6 INCH LINE HOURLY CAPACITIES OF ORIFICES PRESSURE 400 LB. Specific Gravity .600 Pressure Connections at 2^2 and 8 Diameters. Pressure Base 4 oz. Base and Flowing Temperature 60 deg. fahr. Atmospheric Pressure 14.4 Ib. All capacities expressed in thousands of cubic feet. 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o; O b-' O5 i-H rH rH rH O5 O5 rH rH rH CO rH CO' CM CM 00 00 O 10 CO O 05 CO O5 CM 00 IO b- O5 rH rH rH rH CM g 1 CO O5 O CO O5 O CM CO rJH O5 CO CO IO CO rH CD rH rH CM CM CO CO b- 05 O b- CO CO 00 00 ^ TJH 8SSS O CM CO 10 rH rH rH rH ^ rH rH 05 lO b- b- CM CM b- TJH CO CO b- *H CM CO 05 05 rH rH CM lO CO CM rH rH i 1 CM 10 rH CO O CM 00 00 - CO 05 O CM ^ CO rH rH rH rH CO lO rj< O5 O lO O5 CM CM CM CM CO CO IO o CD b-' CD' Tj< Tj< 10 CD rH Q Nrf CO 05 -^ -* CO CM CO Tt< CD r}< 10 00 CM CM CD CM IO IO CO b- CO O rH Tj< rH rH rH CD O CO CD rH CM CM CM CM b- iO CO CO CO ^ lO SS8 rn'grHCO >0 O CM CO H O kO b- CO CM CO "tf CM CM ^ Ttf IO IO CD CO O5 rH i-H 00 CO CO O rH rH rH CM CM OJ CO 5< CD rH CO IO ^ lO IO CO \^ -H iO CO ** O5 rH O CO OSrHOb- CM CM CM n< rH^^TM rH CO CO 00 -^ -tf CO b- CO O5 CM T^ lO rH rH rH O5 CM b- rH rH CM CM 00 IO CO "tf O5 CO 00 ^ Tfl s CO iO O5 CM CM lO b- CM CM CM CM 00 CD ^ rH CM CO -^ 10 CO CM CO CM Tj< b-^ CO O r-i i-H rH O5 rH b- CO CO CO O5 CM rH rH rH CM IO O5 CM O lO b^ CM CO CM CM CO CO rH b- iO CM CM lO b- O5 CM rH rH i-H CM CO Tf< rH O ^ o to co CM CO CO TjJ 05 rH O CO CD rH CO b- O5 rH CO IO rH i-H rH 10 CM CM CO l> 05 CM rM rH rH CM CM rH 3383! ssss SSSo CM rH b- rH CM CO CM CO CO CO i 8 '! o W > w > W GO CD CO O CO CM CM LO !> rH i-H rH i-H CM LO O CD l> Tt< O ^ 00 CM CO CO CO ri< O O O t- LO - t> >tf LO CO J> r-H r-H ^ LO CO * i 1 rH O5 r-H CO CO i-H i-H i-H kQ b- 53 CO 00 C\J CO O5 rH CM CM C\i O5 LO O O LO rH r-H O5 CO ^ LO LO I'll! 10 O5 LO 00 O CO GO 05 ve< , CO J> 05 CO 43 ^ g CO CMCo-cSS lO t- 00 i>- kO CO t- 00 t- CO rH T^ O CM LO J> r 1 i 1 rH rH r^ CO CO CO O5 r-H Tt< t> rH CM CM CM a Tt< 05 CD 00 O CO g CO Oi 00 > 00 ^HCvilMCO O5 t> lO CM CO -tf 10 CD CD t- t> CO t- CO O CM CO r-l *& r# CO LO fc- O5 <43 A VHI nH l> t- 00 rH CO "^ o ^ s w S2^^ CM O5 lO r-H CO CO Tj< lO 888g r-H CO ^ ^ rH rH CM Tj< CD rH rH r-H r 1 - ^ r-t o 10 r> CM O O Tt< 1 * d CO CD 00 00 CM rH l> i 1 O5 O rH CO o S CM 10 O5 CO OJ d cvi TH od i 1 i-H i 1 i 1 O t> t- CM r-H lO b-' CO CM CM CM CO t- o O t> 00 CD rj< r^ LO CO ^' r-H Tf< LO l> 00 O5 O CM CM O 10 r-H 00 O I TF i 1 i-H i-H CO O rH CO CD O CO lO r-H CM CM CM CD LO t> CO^'^ ss'gsa S CM CD 00 CO CD t> CO O 10 CO CD J> CM 10 t> 05 rl r-H r-H rH CM O5 CM LO ^CMC^C^ 5J5S8 ^ 1 1 10 10 -^ 00 rji id CD 1> O rH 00 CO 05 rH CM T*J r-H r I i 1 LO CM 00 CO i> d ^ 06 rH CM CM CM o o -^ co CM LO O LO CO CO Tf Tf ^ 1 1 S85|^ CO CO Tji LO CM CO 00 05 CD t- 00 O5 rH O rH t> CM Tj< J> O5 r-H CM 05 CO CM CM CM CO 1 1 05 "* CM CD 05 TH 00 -^ rH 01 CM CO O5 O5 O5 00 CD CO CO Tj< LO CO 00 O5 O5 O5 t> 00 O CM rH LO 00 O5 T^ LO t> O5 Differential in Inches of Water 10 rH r-i CM CO ^ co co o 1 1 2883 g8 rH 367 ORIFICE CAPACITIES FOR GAS s H 8 INCH LINE HOURLY CAPACITIES OF ORIFICES PRESSURE 60 LB. Specific Gravity .600 Pressure Connections at 2K and 8 Diameters. Pressure Base 4 oz. Base and Flowing Temperature 60 deg. fahr. Atmospheric Pressure 14.4 Ib. All capacities expressed in thousands of cubic feet. Diameter of Orifice in Inches CD CO CD ^ Oi r-H r-H CM CM iii@ d d d d kO CD t> O5 CM CM Oi CO r-H rH rH rH lO O CO iO 00 i 1 r 1 i 1 i 1 ii ii CO ^ l>- CO 10 S*Sf CM 00 Oi CO CO Oi CM tO CO r-H 00 O r-H CO -^ r-H OO 00 ^ tO kO CD t- 00 5 r-H r-H CO r-H CM CM ** t> O5 lO r-H CM CO CO t- 00 00 CM CM CO 00 Oi Oi O O CM CO ^ O %$% Oi O5 CD O CO O CM -^ CM Ci CO r-H t Oi ^ CO Sill r-H rH CM CM CO 00 t- 00 ^1 r-H r-H r-H CM Oi rH O CO CM kO Oi CM CM CM CM OO 00 J> Oi CM iO CO S^ S^IS CM 00 O 10 iO 10 03 SS3S8 SSS8 CO ^f CO Oi t> 00 O r-H CO LO 00 00 CO -^ CO 00 CM" 00 > CO iO IO 00 r-H CO r-H r-H CM CM CO 10 CO ^ O t- OO CO CO OO Tt< rj< O3 00 rj< CO iO CO 00 Oi oo oi t> co O rH CO >0 rH rH rH I ( CM CM O CO CM CM lO t- i I i-H r-H rH CM iO O CD t- CM CO CO OO <^ ss! 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CO S^i O ^ CO ? r . -^ H HH Sift o s!s SB a & rt S ll BS3 00 co 00 OS OJ OS b- rH LO O rH OJ 03 CO LO oo o co O O O O OS O 00 CO CO 00 OS rH rH rH rH rH r 1 \ LO LO CO b- * LO CO b- OS i TOO LO b- l 1 rH rH rH 00 CO rH 00 OJ OJ CO OO Ills a CO 33 O b- CO CO 00 OS rH 03 rH rH rH rH OJ OJ oj o oo o 00 rH LO O OJ 00 CO T}< o o CO O3 CO OS OS 00 ^ OS 00 O3 OO CO ^* CD OS O OS LO CO 00 00 OS CO LO OS O OJ LO b- rH rH rH rH o os co 03 O rH LO 00 03 03 03 03 03 CO b- rH LO 00 rH LO 00 00 OS O OJ Tt< LO rH OS OO CD 00 O CO c OJ o oo os o s38 rH b- b- 00 O OJ LO 00 O O CO -^ b- OS ed 5 S OJ b- CO LO LO 00 rH CO rH rH OJ OJ CO LO 00 "tf O l> CO 00 CO CO ^ ^ OS 00 rf b- LO CO 00 OS 00 OS b- OJ O rH CO LO OS CO 00 CO rH rH rH O3 00 rH b- CD CO OS 00 b- 03 03 CO CO i l $83 i-H rH r I O O O O OS rH O3 LO 000"* 00 OJ 03 Tt< C5 OS b^ CO ^ "^ LO Tt< O O O CD b- 00 OS i I CO i-H CO Tj< CO 00 OS rH rH OJ OJ b- OS CO CD GO O rH rH rH 03 CO LO rH b- LO OS CO rH O3 O3 CO Tt< b- CO rH OS CD T}< LO LO CO rH 10 LO -^ 00 Tt< LO CO t> O rH 00 CO OS rH O3 ^ rH rH rH LO O3 00 CO t- o rt< oo rH OJ OJ OJ iiii H OS CD rH O OJ CO ^ LO 00 rH 03 03 LO i> 00 OS oj o os co r-J CO LO 00 i-H rH rH rH LO LO OS OS Differential in incnes of Water LO rH rH O3 OO ^ CO 00 O rH rH OJ CO ^ LO CO 00 O i-H 369 ORIFICE CAPACITIES FOR GAS , iH o S 0) Oj g II W --^ c* W I r oo S s S-o tf if CM CM rH rf lO CD rH {> t> 00 rH CO T}< O CO O5 CM b- CM O5 lO rH rHrHCMCM CO 00 Tt< lO ssss rH CM Tj< CO O O t iO O O ^ O5 rH CM lO CO CM iO rH rH rt rH CM CM rH t t O O O CO rH CO rH O5 CO 00 Tf ^ lO lO CD CO O5 CO 00 rHrHrHCM CMCMOOCO COiOCOJ> COt-OO OCMiOt- O5rHiOCO rH rH i I rH rHCMCMCM rH t- CD tr~ 00 T}< O5 > CO 00 CMiOCMJ> CDO-^CM TjHt^O 1 ^ COiOOlO rHrHCMCM CMCO-^Tj< OOCM001> COiOkOCM COCO d od id od r-i cd d ^ r-i rH rH rH rH CMCMOOCO T*< O5b-CMt- XTj<-^O COT^CO t> 05 rH 00 10 05 CM IO O 10 00 O CD r-i r-i 05 i I rH rHrHCMCM COOOrJt- O500-^CM rHTj lOCOJ>O5 OOOlOJ> rH Tt< O5 T}< CM CM CM CO IOCMO5O O51OOOO5 ^TtO5CO OO^T^CD CDOOO5O OOlOOOrH Tj rH t- O5 O OO rH rH rH kO rj< O5 kO 00 rH 00 rH rH CM CM 00 00 ^ 00 O5 00 rH t^ CM 00 <* Ttf kO kO CO t- 00 kO kO CO t- 05 rH rH rH rH 00 CD rH 00 rH Tt< O Tt CM CM 00 00 O5 CO CM O 00 CM O5 kO 00 ^ ^ kO E "o a r 1 rt o 00 'g y 00 - S t- 10 05 CM t- O5 O CM rH rH O 00 CM kO kO Z> rH T}< rH rH CM CM ^ O CO CO t^ O ^ 00 CM OO OO OO a -rH T-t PM O x^ O O MH O * ' S Tj< 00 O rH CO i> 05 O rH OO CM -^ rH CM r^ t- O rH rH rH CM kO CO -^ O5 CM ^ 00 rH CM CM CM OO C/J rt C ' (U O 00 00 O 3 H hH & M rt . 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CM OS t- t> lO O iO 00 CM 00 CO Tt< g8 06 oo oo d OS rH CO CD OS CD CO CM i> OS CM iO CM t- rH 00 O OS -^ J> -rti rH CM CM 00 00 rH SO 00 00 "# J>OOOCM ssss rH O CO CM 05 IO CO rH lO rH rH CM CM O CD CM t- CO CO ^ ^ CO t> CM Tt< iO CD CO OS CD CD rj< O O rH CO IO i 1 OS 00 "* OS O CO lO CO 00 t- 00 iO rH CD O ^ CM CM CO CO CM t~ 3$ii rH rH\ rH iO CM CO O J> 05 d 00 rH rH O 00 CM t- IO 00 rH CO rH rHCMCM O iO O ^ OS 00 rH !> CM 00 -^ r^ oo oo i> id iO iO CO J> rH CO OS 00 00 Tji id CD 00 CD CO CO CM O5 rH OO lO CO lO 00 Tt< rH CM CM CO OS CM OS O Differential in Inches of Water iO rH rH CM 00 -tf CO 00 O rH ssss go o o CD 00 O rH 372 ORIFICE CAPACITIES FOR GAS s CD am 00 OS O rH o' o' o o rH CM CD H/l CO LO 00 rH rH rH rH CM iiii , 8.0 D m ^ (/) 2 ^ LO i-H LO rH CO O5 CO C^ CO rH CM CM CO Tf O O O 00 t> rH rH CO Tj< lO CD Tf CO LO rH co Oi CM rH V> 3 *" III PH $ 5 CM LO CM t rH rH CM CM 00 LO O LO CM CO ^ TH LO ^t* 00 O rH rH CO CM O rH CM ^f rH rH rH rH II LO OS 00 CM O CM Tj< CO rH rH rH rH rH LO Oi CO CM CM CM CO III! l>- 00 O5 O rH c/3 . .2 8IJ! 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Pi $ rH 05 TH b- CM CM CM 00 10 00 CO -^ CM 00 CO Tt< LO CO SiSS CM -* O rH r^ CO O CO rH rH CM CM O5 LO b- LO CM CM 00 CO h 1 g <*-i CO CO >O 00 00 O CM rH So | f b- 05 rH T^ rH rH CM CM b- r^ O5 00 CM CO CO -^ iO 00 00 00 lO CO b- 00 b- rj< CM CO O CM LO b- O5 rH TH t- rH CM C>CM O" S c: CM b- rH CD b- iO Tt< O CO ti t-0 8 n4 g o CO CO * CO 00 O lO O5 CO CM CM CM CO rH rH O5 CD tf iO 10 CO H CO Tt< CM 00 O5 rH 00 b- rH CD b- T}< CO 00 O O O 2\ 43 il eq -r-> o 00 Tj< iO IO OO O5 O rH OO O5 CM O 00 T^ 00 r-i 10 00 T^ rH rH O5..CD CM b- CO* b- CM Tt< IO 16' CO O5 !o W '" -b rH rH rH rH " |_ j g , H .2 V* 05 00 b- CM l> 00 05 rH ^ CO CO CD CM'lO b^ rH rH rH rH CM O CD CO lO id d id O5 CM 00 CO CO CO 00 CO 00 O5 Tt< LO CD b- 00 b^ CM Tt< 00 05 rH CM rH rH 10 CM 05 rH CO I> t-^ 05 CM iO Tf< b- d CM ^ t> rH rH rH rH TJ< O 00 iO O iO 00 CM CM CM CM CO lO CD O5 lO CO lO CO -^ iO CD gigss ||-| CM 00 00 CM CM O lO rH 00 O rH 00 CD iO b- HH 1 2 OJ CM IO 10 CD b- 00 O rH Ttf rH rH rH siciis rH CD -* CM CO CO ^ *O S8e2 8 Is g 1= CM O 10 05 b- ^ 05 rH rH CO b^ O5 rH 00 b- CM CO CM id 06 d rH rH rH CM O5 b- CM CO r^ 06 id d CM CM CO ^ T^ b- 10 05 b-' T< TJH T^ 10 CD ! rH O5 IO 00 CO O ^ b- CO 00 CO CO ^ O5 00 O 05 10 TJ< CD CO CO 00 O CO Tj< 05 CM CO id rH rH rH O5 00 b- OS 00 rH CO O rH CM CM 00 lO CO CO 05 CO 00 ^ ^ OfL, \N CO CM b- O5 CM 10 b- rH 10 TO rH CM rH b- rH 00 00 O CD CO CM b- 05 00 w rH CM CM CM 00 CO ^< iO CO b- 00 O rH 00 CO O5 CM IO b- rH LO C\2" CM CO CO 3p rH b- iO CM CM lO b- O5 CM rH i 1 rH CM CM CO 00 -^ 05 rH O 00 CO rH CO b- O5 rH 00 LO lO CM CM CO SI g r-H s + i p in Inches of Water ^ CD 00 IO rH rH CM 00 ^ CO 00 O 288S 10 CD 00 O rH 376 ORIFICE CAPACITIES FOR GAS PQ ? 00 00 CD CM rH CM CM OO g rj< CD OS OS CO ^ CO 00 t- CM CD rj< CM lO 00 rH CD. i-H rH CM CM" : lg| d o d d OS 00 00 CD LO CO 00 OS t- b- CO CM O rH OO LO ^ ^ nH rH W 0) CO cS CD rH t~ O 00 CM TH i> i-H i-H i-H CM O CO Oi Oi ^ Oi CO t>- OJ CQ CO CO CD rJH CD CO Tjl lO CD i> 0000 LO OO t rH 00 OS O CM w Cfl W "" 2 3 3 H CO CD i> id id 05 rH 00 CD i-H rH rH sill OS t> O O CO CM CM O 00 -tf LO CO g'^ss CO IS- 00 OS S 2 I 2 10 rH i-H rH IO -^ OS IO 00 rH 00 -H i-H CM CM 00 00 ^ 00 OS 00 rH t^ lO LO CO t- p< . 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OO O 00 00 O co I-H CD id CM 00 00 ^ rH ^' Tji CM LO CO t- 00 rH CO CM -^ 00 O 00 CD rH CM CM CM s . ^ o i> O O iO LO OS JD 0) .s )_t 00 2^8 t> lO 00 OS 00 ** iO LO 00 Tt^ 00 OS J> 00 O rH 83 rO oi pH 0) CO rH rH O CM CM rH OO H r i O 43 So 2 Q OJ SSi^ i-H GO -^ OS 00 00 ^ ^* O iO OS J>OOOS Ss Si < S? a * o s 00 t> CM CM CM iO 00 CM i-H rH i-H CM J> rt* 00 CO IO rH CD O CM 00 00 "tf fc- rH 05 10 00 OS OS rH CM i-H i-H 11 CM 00 CO CO 00 O CM -^ J> CO CM rH CD O iO OS CM CM CM CM 00 05 rH CO O CM CO t- 00 OS O o !f rH OS Tt< O CO 05 rH M< l-H rH CM 00 OS CD CD OS CM iO OO rH 00 i-H CO T}< rH 00 00 T^ 10 t^ CO CM rH lO CO t> 00 rt M <1 CM CO J> J> Tj< rH LO LO OS CD 00 i-H i> OS sl rH CD l> 00 O CM LO l> OS i 1 rH i 1 rH 00 t^ 00 OS 10 CM rj* Tt< iO CO w ** fa > d \N iO lO <* 00 Tj< 10 CD 1> O rH 00 00 OS i-H CM -^ i I rH r- 1 10 CM 00 CO t> O Tt< 00 rH CM CM CM O O rt< O s 5 i rH 00 -^ T^ CM CD 00 OS rH O rH t> O5 CM O5 rH r^ 00 00 ri< lO CO l> 00 OS CM T^ l> OS i-H r 1 rH rH CM CM CM CO o g S O t- Tj< rH lO O IO CM CM CO 00 8 gg t- O5 rH CM CO lO t- rH CO O lO CO t*~ Tj i> O ri< CO rj< rH rH CM CM CM CO 8RS rH CM ^ rt< TJ< {> rH rH rH rH CM CM CO CO ? o t> O CM 00 O rH rH rH rH rH CM CM CM rH IO ^H O5 CO CO O51OOOO OOO51OOO COCOO5OJ COCDO5rH rH rH rH rH CM o ^~ 00 CO t- rH rH O5 O CO lO CO O5 00 00 CM CM CO rHOOOrH CMOlOO5 T^lOlOt- OOOrHCM CO t- Hj< rH 00 t~- CM CM CM Oi O5 rH rH O i-i CO rH 00 Tj< CM CM CO 00 T^ IO 00 O O5 00 05 CM CO CO -^ O5 t- CO CO O^CMOS Ob-^^ 10 CO rH 10 rH rH CM CM OOt>CMiO COCO-^O IOCOOOO5 OrHCOlO Ot>OOO OOOO5O5 CM ^ t> O. rH rH rH CM i co r> o 00 O5 O CM TtCO^Tf O5rHt-O5 05 rH CO CO CM CO CM 10 i> cd d cvi O5 CM lO CO POT^T^rH IOO5COCO lOCOl>O5 OCMr^CO roiooocM rHt>oo SrHr^S iS^Si COlOCMCO COOTfCO COT^lOCO !>O5OrH CM -* O rH 00 CM CO CM CO 00 iHrHCMOO rJ, > CS rH CO 00 O5 rH rH CO CD 00 O i 1 rH rH CM LO O5 LO rH CM CM CO TJ< ^SSS 2 ~ 0) rt i I LO 10 T* 00 -tf' id cd i> O rH 00 CO C5 rH CM Tt< rH rH rH lO CM 00 CD Tj< CM LO O LO 00 00 ^ ^ W o S a w Differential ps y o3 3*0 LO rH rH CM CO "tf CD CO O rH S8SS 10 CO CO O rH 379 ORIFICE CAPACITIES FOR GAS a So w is # fil 1 S 5 ^ CO ? I Iff! Pf! CM p, ^ o Is hri w> |i, sl to ^ O5 tO lr to * 00 O CO c t- i-H lO OJ OJ ( o rH Tj< LO CO O5 rH CO O CO ^ lO 00 CO O CO OO i 1 (M OJ OJ CO 00 i-H O 00 O t*~ CO 00 "tf "tf tO Tjl rH i- O to t- CO CO 00 CAJ i 1 i 1 i 1 OJ O -tf co ^ rH t> rt O rH CO CM rH CO to O5 CM CM CM CO O5 rH O O O5 CO CO LO CO Tf to CO CO O CM 00 O CO rH CO ^ LO 00 lO ? CM CM tO CO i> CO t- C O b- Tt< tO t> CO t- CO 00 CM CM CO CO CO T}< O O CO t- LO rH tf r^ LO CO t CM 00 i 1 CM CM Ccb rH rH rH CM rH CO CM CO CO lO O5 CM CM CM CM CO i> co QO OJ CO CO CO rH ^ rH f^HrHrHrH i-HCV3Cv3CV> 5.-S COO5CMO t-CMO5CM C005CMTj< LOt-05CM 05 05 CM Oi t-' i-H tO O nH CM CM CO O5OOOCO COOOOO5 COOOO5rH CMCOCOl> O CM 05 CO T^ t>" Oi ^^ rH rH rH CM 00 Tj< O5 T}< CM CO CO -^ O5 O5 CO O 05 O CM "tf J-^P-lrHLO TiHCMCMCO Tj O5 i I CO tO rH O 00 lO CO 1> t~ TJ< CO CO ^ 10 cd i> oi CO CM CO rH O CO td t-' O5 rH CO CM CM 00 CO CMCMCMCO CO-^-^tO ^^CMCO ^COXO ^000 0000 380 ORIFICE CAPACITIES FOR GAS a cn co g ^ rvi o ^ ^ .S < H I . *d H |y w > 51! w I o & S CO u, M 4) S 1- I'o Cvl CO O5 o o o o LO 00 LO b- T^ CO O CO rH i-H OJ OJ 00 lO lO b- 00 O5 rH 00 CO OJ Ol OJ ^ Oi CD .cb co I~H cvj co TF b- rH o oo CO 01 CO Oi O rH CO rH OJ OJ O 00 CO ^ CO ^ LO ^ lO Tf Oi CO CQ "* 00 rH rH rH OJ "~ ~ C\l CO -^ rH 00 b- co id i-H Tt< CO i-H O CO > 00 00 LO CO b 00 Oi O rH i-H i I Oi b- OJ 00 b- OirHOJlO OOOJLO OJb-OOO OOOO LOOOib- TfOrHrH OO-^^iO COb-OOOi O LO 00 rH Oi rH b- b- 00 Oi OJ OO b- Oi O rH i I O OJ b- rH 00 "* Oi OJ 00 OO T^ T^ rH kO 00 05 O rH 00 Oi CO O rH 00 b- rH OJ OJ OJ 00 ^ (M r-H (M (M'OO CO Tt< Oi Tj< O rH O5 rH rJ4 CO O 00 00 Oi ^ O 00 00 id oo O lO 00 LO OJ LO CO b- OiOb-iO OiOiCOCO b- rH LO 00 rH OJ OJ OJ b- i-H rH rji O oi b^ 00 -^ ^ LO r-H i-H OJ CO TH CO 00 O LO O O O OOOO rH rH OJ CO T}< LO CO 00 O 381 ORIFICE CAPACITIES FOR GAS a M 8 S . c/3 3 CO ^ ^ W $ g *i a ill P ss o W o . o ^ co O rH oo CVJ H^ O rH ^ CO O 00 rH rH CVJ CQ a.3 cu o rt o ^ ta +H '^.a t> 00 OS iO iO OS ^222 iivi^S CO CO lO 00 ^ kO CO t- OS 00 CO lO 00 O C\J T}< i 1 C^l > rf 00 CVJ 10 rH i-H W IM OO 8 o rH OS lO t> 00 OS rH 282 T^ CO CO <*" CO O 00 rH rH CVJ-'CVJ iHCOrHrH CvJCOb-CO OOCOrHiO COJ>COOS CO OS CO 00 rH 00 l> O CVJ Cvj Cvj 00 CO rH rH O CO rH OS CO CO O 00 OOrHOSCO lOrHi>> rH CO t- CO rH CO rH 00 rH rH CO CO OS O rH CO CVJ 00 t- d oo id co CO 10 10 CVJ Cvj CVJ 00 00 O 00 CVJ t> ssa-ss 5J^ S rHrHCVJOO rH CO 00 O O O O 0000 382 ORIFICE CAPACITIES FOR GAS PQ o fi o * CO W * r- js P=^ : - a o I s, & SI *t 5 .So ls o o X CD Tj< CO tO o o o o o co t o t^ oj CO CO rH rH to 00 i> O5 CO OS OJ rH tO rH OJ 1 Tj< 10 LO OS CD CM i> 10 C\J CO CO TH rH rH rH rH rH OJ OJ OJ rH 00 rH OJ i> rH 00 OS rH CO rH CD CO O i 1 CO CO O CO 00, I-H W -H 00 10 OS O 00 00 OJ OJ OJ OJ 00 ol IO CD rH tO CO 55 i-i l> d OJ t~ 00 O <-> OS OJ rH OJ -tf l> rH l> rH IO OJ CO CO t-OrHO Ot-COO OJrH tO t> CO OS rH OJ 10 00 OOl CO ^ t- 00 W OJ CO 00 00 ^ to CD t^ CO iO O 00 O rH OS IO OS rH CO CO CD OJ 10 t> -H rH rH rH OJ O CO CO lO to o to os OJ 1 CO CO 00 CD CO OJ O 06 d oj to CO OJ rH CO tO CD CO OOOOi>tO rHt>l>CD OOCOrHiO COCOJ>OO rHrHOJCO rHCOOOO o o o o tO CO 000 383 ORIFICE CAPACITIES FOR GAS Table 114 4 INCH LINE HOURLY CAPACITIES OF ORIFICES PRESSURE LB. Specific Gravity .600 Pressure Connections at Flange. Pressure Base 4 oz. Base and Flowing Temperature 60 deg. fahr. Atmospheric Pressure 14.4 Ib. All capacities expressed in thousands of cubic feet. 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CO T* rH CM CM rH 00 CM ^OrHb- CO OS CM rH CM CO -^ LO CO b- 00 00 O rH Tj< CO OS CM b- CM CO CM CM 00 CO ^^s ~\ 00 b- rH ,-H 00 T* O 05 b- CO O5 O O O b- LO 05 OS CO CO b- rH rH CM CO ^ ^ LO CO CO 00 OS rH CM LO b- rH LO 00 rH CM CM CM rf< O 05 b- CO CO -^ * LO CO CM b- rH 00 CM CM CO CO ^ 05 Tj* CM Tt* Tt< LO CO OS LO 00 rH CD 00 05 CM rH OS rH b- O CO 1> 05 CM rH rH rH CM O rH rH O CM 558$3 w Scbgg CO 00 -tf 05 CO J> rH 1> 00 CO CO CO b- rH rH OS b- OS CO 00 00 rH CM CM CM 00 CO Tj< Tj< LO CO b- OS O 00 LO CO rH rH (-4 'rH CM CM CM CO CO CM LO 00 CM CO CO CM rH LOOO.-H CO O O b- O rH OS TH 00 CD rH rH CO CO rH O rH iH rH CM CM CM CO CO ^ LO LO b- 00 05 rH CM rH rH LO 00 CM LO 00 rH rH CM CM'CM 6 ^ 8388 b- OS O5 T}< 00 O CM CO LO rH b- O5 CO'rH rH OS CM 00 00 "tf CM CM b- 05 "8 rH iH rH rH CM CM CM CM 00 * LO LO b- 00 OS r12;SSg 0> Soi2 O CO O -* OO^COOO LO CM rH b- O LO OS LO CM rH O 00 LO O CM CO O CO 1 ^ 1-4 rHrHrHrH CM CM CM 00 HH LO' LO ? CO CO O5 rH CO Tt< i-H rH rH p S^g^ CYJ cvi rH b- 00 05 O rH rH O LO b- OO CO 00 CM 8^3 rH 00 CM CO CM rH i-H i-H rH rH CM CM 00 00 -^ LO LO b-.OO OS * OS rH CM rH O5 LO lO CO CO ^ LO * LO b- CM CO CO 00 CO O CM CM 00 ^ CD CM b- CD TX LOLOCO Tj< i 1 lO O5 b- 05 O CM CO CM O LO HH 00 rH CO b- CM CD O5 00 CO O CO CM rH rH rH rH CM CM CM CO -^ rj< lO X 00 OS O CM rH rH CM CM il rH CO CO OS LO CO b- 00 CO CO CO 00 O CM ^ CO O5 O CM CD Tj< OS CO 00 CM CO rH rH rH rH rH CM CM CO 00 X rH rH i-H rH O CO LO O5 CM CM CM CM O5 O CM O CO b- co ^ -^ LO S8SSS b- CO OS b- rH CM Tt< b- O 00 rH rH rH rH CM CM Sss grl +j G 03 030 = oog LO * G K fa-8 rH rH CM 00 "tf CO 00 O rH sss-ss 385 ORIFICE CAPACITIES FOR GAS os CM n< oj CO r-H rH OS 10 CO 00 9 O CM 00 t> rn" CM CM CM 3338 CM rH rH CO CM 00 tO t- rH i 1 rH rH CM CO CO tO 1 CO OS O CM CO CO CM lO 00 CO OS OO rH CM rH OS t> 00 00 CM CO rH rH CD CO to' i-i CD w g i-H rH i-H w js CM J> 10 CM tO CD J> CO 05 CO O O rH O CO tO CO r-H i-H r-H rH CM O O to rH CD O CO CM CM CO CO rH rH to CO tO CM tO CO t- 00 OS O r-t *l . 2 CM CO rH rH tO to CD t> 00 rH t> 00 CO O i-i rH i-H rH il tO CM CO rH CO O CO CO rH CM CM CM OS OS rH 00 rH rH 00 tO CO l> 00 co i ^ 8 M jq o IwS 00 00 O O CO I> OS i-i 1 1 i> CO O rH CM tO CO O rH rH rH CM CO rH CO CM O CO s r| i i .s 8 S rH OS CM OS O 00 t> CM 00 CO CO rH J> OS 00 CO rH to co 00 CD CO CD CM OS rH CO tO CO to 00 rH 00 rH CD O rH CM CM CO OS CM 05 CO PH $ O FJ O 2 -S o "o i-H CM CO CM rH CM CO OS rH i-H CO Z> CM CM OO to OS CM i 1 rH i 1 CM 00 CM rH 1 rH i> rH LO CM CM 00 00 IJJl OJ s i 1 rH rH r 1 CM rH OS tO 00 rH 05 rH CM CM CM 00 rH CO O OS t> rH CO CD J> tO OS rH rH 05 O 00 10 OO O5 CO rH l> CO rH rH O CO OS rH CM rH tO i 1 i-H rH rH H I'w * H a X .^. 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S| 8S 3*1 s M I 1 i-H OS "^ ^ r-t CO OS co ^ ^' id CO ^ l> 00 CO 00 OS O CM CO > CO 00 lO CO rH rH rH rH CM CM 10 CO rH <^ CO O -^ CM CM 00 CO >3 l 1 ^ s 00 00 O t-H CO 10 CM 00 00 ^ rH Tf< T^ CM id co t> 06 rH CO CM ^ O rH Tj< CO rH rH rH rH ^ rH CO O CO O CO CO rH CM CM CM il 5 X oi^^SE r-i CM CM CO CO ? -tf rH co Tt< id co ^ CO 1C rH t> CO O CM CO OS CM CM CO T}< I> OS 11 2 > S ^ ??S88^ ^i r-1 r-! CM CO CM t^ CM CM CO CO -rji CM O CO -tf lO CO t> CO tf CO OS CO OS O rH 00 w m 1! x lO lO i I 00 CO O CM "tf i 1 i ) r 1 rH O CM rH t> rH T^ J> rH CM CM CM 00 00 CO -^ co co ^ id rH CO t- lO CO CO t- 00 W i ^ Differential n \_, ^S J OS 1% = 10 -H i-J CM CO ^ CO 00 O S3 10 co oo o I 1 390 ORIFICE CAPACITIES FOR GAS S 00 CO OO rH IO Th IO CO t> GOOCVJOO b- CO b- OO CO 05 CO t> IO lO CO O O 00 CO OO M CVJ CVJ 9 g Sj OS LO O5 00 r-i J> 05 OO ^ Tj< lO CO CO CO J> CO 00 05 O rH 00 So 00 rH rH rH rH CVJ ^'g^ Cvj CVJ 00 OO K IO lO lO OS CO CO M rt .0 Cvj CO CVJ t- lO CVJ OO 00 T^ CVJ lO lO rj< IO CO i> 00 OO OS lO CO rH ^ CO rH rH rH rH t> lO b- lO 00 O 00 CO rH CVJ CVJ CVJ E w Cvj PN 3 to . 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CM 00 CO -H CO t^ 05 rH CO i 1 rH !> CM CM 00 tO OS CM "^ rH rH CM CM tf rH 05 CO tO rH O 00 tO CD t- t- O *" rt W> S ~H _^ 'S ; $> . o co to * co i> 06 d rH o t- o o CM ^ l> 05 rH rH rH rH CM 00 OS OS CO CO CM t- CM CM CO CO T}< lO CM CD Tf< O ^ H< tO CO W s^ \cq Ti< Tt< CM CO GO 00 Tj< OS O J> rH 00 rH rH "tf O - d rH T^ 10 CD J> 00 O CM CO rH T^ OS ^* CO CO CO ^ > OJ 2 NC* lO CO J> CO CO rH 10 i> i> 05 J> OT -^ CO I> -^ CO w 1 rH CO CO Tt< tO CD 1> 00 05 rH CO CO OS rH rH rH rH rH CO t> O CM CM CM CO >-H 1 CDrHOOO Oi ^ c*~ ^ S 00 CO CM CO 00 00 -^ OS CM CO CD H-4 rH CM CM CO CO -^ 10 CO t- 00 O CM CO tO 1> O5 w o r ( oo Differential IS II S'S 10 rH rH CM CO Tj< CO 00 O lO O O O rH CM CO -^ tO CO 00 O rH 407 ORIFICE CAPACITIES FOR GAS a* CO rH T^' CO 10 O CM ^ t> rH rH rH i 1 O ^5 CO rH CM CM CM CO rH CM O O OS iO iO T^ CO TjH lO CO l> t- Oi O s 5 8'28 rH i I iO CO CM Oi CM iO IH's iO Oi iO O LO CO J> CO W g B: CO g .0 10 ^^8' rH iO 00 CO l> CM iO t> OS CM CM CO CO rH 00 O O CO M - a 53 P^ M 5 00 OS 00 Tt" Tj< iO CO 00 t- OS t> 00 OS rH CO lO rH rH rH t> CO lO CO CO rH CO O rH CM CM 00 il - 9 ft w b-' CO 00 -^ 00 rj< lO CO Tj< rH id CO t- OS O rH rH rH Tj< CD Tj< LO CM CM OO CO CO -S.3 W . o 3 hH ^ a; o rH CO rH CO OS OS CO Tji Oi 00 CM CO 00 Tt< iO CO 00 00 CO LO OS CM iO t> rH rH rH rH Oi 00* rH rH LO 00 CM CM CM pri e? *** J2 f 00 CO CM rH t- d 10 oi 10 CM CM CM 00 CM 5JSS!g d CM co d 00 OS rH CO co o T}< co ^ CO CO O 2 tC rH rH CM -M W pt< (tf 3 2 CM OO 00 CD rH l> r-i rj< d rH CM CM 00 CO CO CM s^^'s t> 00 LO O CO J> OS rH rH rH rH rH rH s f|-| rH rH CM CM CO O * CM oo 10 o 10 CM CO -^f T^ LO Tt< 00 O LO CO J> OS rH rH rH rH gj is | Q CM CO CM Tt< rH rH ^ CO O rH rH rH CM CM ^ CO t- 00 CO CM CO CM CM CO 00 05 SiSS ^ 2* 'o rf a CM CM CM O OS OS rH CO 10 rH rH rH Tt< iO O O CO CM CO OS rH CM CM CM CO rH CO ** iO iO id rH CM CM CO J> 00 OS r^ O 10 CO rH t> CO OS CM O rH t> rH H 00 00 CM CM CO CO ^ Tj< s _>, -g IH CM 00 CO OS lO CO fc- CO CO CO CO CO OS O CM CO OS 00 00 CM rH CM CM OO ^ OS rH > cS 2 rH" CO T*< rH CM co ^ id cd rH t- rH CO l> 00 O rH rH rH 00 O CO CO 00 CO OS CM rH rH rH CM CM J> OS 00 IO l> rH IO CM CM 00 OO =1 rH OS CM iO 00 CM 00 CM OS CM CM CO CO CO lO CO TJH 10 CO J> OS CO CO IO CO O CM -^ rH rH rH CO 00 CO OS CO J> O CM rH rH CM CM 1 r ( 00 Dififerential y 1 /} i, i 53 H r^ H M-l 3 O iO rH rH CM CO rt< co x o rH rH CM 00 ^ LO CO 00 O rH 408 ORIFICE CAPACITIES FOR GAS W N w o E O E S o I o *is I w 5 00 co rH rH rH CM llsl 1111 OS 00 CO CO rH rH rH\ LO OS rH O rH 05 CM r^ b- i 1 rH rH 00 CM O CO OS rf 00 rH rH CM M CO li OOO b- OS OS b- b- 00 OS LO 06 LO o LO b- OS rH CO rH rH LO O O CD LO OS CM ^* rH rH CM CM rH b- CO rH O ^ CM OS LO o os oo ' 3 * 00 LO Tt< b- 00 O rH CM Th b- OS rH I 1 rH rH CM 00 OS OS CO CO CM b- CM CM CO CO ^ o o o ^^i s M ~v t/> * CO b-' CD O "tf LO CO 00 CO "^ rH J> OS rH CO -^ 00 O LO OS rH CM CM CM 00 OS lO O CM LO rH CD ." fj 0) 05 CO CM ! w O o o d rH CO ^ CM OS O 5-2 LO CO rH O CO LO OS CM CD O rH O5 H^ l> r-H rf CM CM CO CO S "o a 8 eg CO CD CM rH CM LO rH CO ^ CM 00 00 ^ LO CO b- 00 OS ^' O rH C5 rH T^ CD rH rH rH O 00 00 CD 00 OS CM LO rH rH CM CM 1 O *8 CM lO -^ LO Tf< rH CO O t~ CM CM 00 00 CM CO CO rH 00 T^ LO CD CD 00 OS rH CO S?3 +j 5 2 -M 00 OS CM OS b- b- ll acities N CO O rH b- r-H r^ CO OS 00 OS CM rH CM rH rH M O i i b- b- CO rH 00 O CM LO -^ TH b- CD rH CM CM CM 00 O 00. CO OS b-' LO CO CO r^ LO gggg fa \M ^ 05 rH rH CO Z> OS rH 00 b- CM CO CM LO 00 O rH rH rH CM O5 b- CM CD "tf b- 0) NJ* Tj< ^ 00 b- OS OS CO O CM 05 00 rH Tj<^b-Tj< pq ' rH rj< LO CD b- 00 O CM -^ r-iS^CM ^1^253 00 CO 00 ^ rH ^| OS 00 ^ 00 TT O OS CM 00 Tji T^ b- O rH O LO b-^ 00 05 O b- CO O rH CM LO 00 rH rH rH rH CM rH LO T^ CM CM CM CM Differential r + J LO rH rH CM CO ^ CD 00 O LO O O O I 1 CM CO * LO CD O 409 ORIFICE CAPACITIES FOR GAS 3 W N ' 6: S CO SI > i * W -3- O & 3 B ji* o g fe o a 5| o W w V -O Qj Is & VH QJ fi 3 w 14 8 5 00 .a fe ^^^ 1^ s-^ lO 00 i 1 >-H <-< (M rH O5 O5 t- CM J> CO Tf rJH I-H co LO 00 CO Oi CO tr*" CM CO CO rH CO CD 00 CM rH rH rH rH CM LO O O O O rH i t O5 CO CM H/I O LO CD t> O O O O rH CO fj< (M LO LO CO t> rH CO t> CO rH CO LO t- rH rH rH rH CM LO 00 "^ i- COOOOCO t~ LO CO GO COOOCOCD O5CMt-rH rHrHCMCM CMCOCO** i-HLOJ>l> O5J>00^ CD1>-^ COl>OOO5 rHCOCOO5 i-HCOt- rH rH rH i I CM CM CM 00 lO rj< CD LO i-i CO Tj< i-i CO CO rH O LO' CM CO CO ^ LO CO t> 00 O rH CM O5 O 00 00 05 CO LO rH rH CM CM CO CM CO rH (H CM rH CO rH CO LO CO 05 rH rH rH rH CM CO rH -^ 05 J> rH Tt< O5 rH CM CM CM COOOCO1> -^LOt-CO COCOO5CO J>COOOCO rHrHrHCM CMCOCO^ 00 LO -^ O5 CO LO 00 O LO O5 CM rH CM CM CM CO l>r^O5CO TjrHrH05 J>O5COOO 00 rj< O5 LOCOl>O5 OCOLOCO OCOO5CO l>rHj>CO rH rH rH rH CMCMCMCO CO TJ< Tt< LQ OO^t-00 CMCOt-CD CMLOCDrH rHrHCMCO ^ CD 00 O JO O O O ggOO 410 ORIFICE CAPACITIES FOR GAS 9 CO CM rH "* 05 b- rH Tf 05 rH CM CM CM isn o o o o CO b- O5 O rH rH rH rH rH LO CO CO CM LO CO CO 05 CO rH r 1 i 1 CM ilii O O O O CO rH rjl CO lO CO b- 00 LO rH CO O CM CO I 1 rH rH w N CO OS J5 10 O CO LO 00 i 1 i 1 rH i 1 CM 05 CO CO i I *sf O O r-H b- 00 b- LO CM LO CO b* 00 O5 O CO "" ill * i 1 r 1 rH CO O CO CO rH CM CM CM O5 O5 rH O rH CO LO CM CO CO ^ LO LO CO b- 00 3 " w .jj * rH CM 10 00 Q rH r-H rH CM CO <*' 00 CM CM CM CO -^ 111 o f} CO 'g -g W I'd O 5 1 o rH O OJ fl rH CO 00 OO' b- CM -tf LO CO 00 lO b-' id i 1 O5 r- 1 CO LO i-H rH r-H H^ CO rH rH 00 rH CO O rH CM CM CO ii fe ; fl o rj B %< * o s 1 g CO LO CO O rH CO -^ LO CO O CO O5 rH b- 00 O5 rH CO b- CM CM CO LO O5 CM rH rH rH CM |g -4-> CO |_ -tf 1 1 b- j^rj ^ w o 11 co ** "^ O "o N O5 CO rH rH CM CO "* LO ^g "tf CM CM b- r-H CO CO 00 1111 O M i'3 >d Ctf rH O 1) 01 CO O5 LO CO CM CM CO ^ 00 00 O 05 b-' HH CO CO b- gSSS! CO O5 00 CO b* 00 rH ^ H^ W co rH o co ^ 0> "O OS 2 V rH T* CO LO rH 00 r-H CM LO rH CM CO O5 O5 W ^ n -I co b- oo o rH CM "tf b- 05 rH r 1 rH rH CO i> CO 00 CM CM CO CO S^Io'S 1 1 1 O5 00 LO 00 CO -^ LO CO 00 CO O CO l> 05 rH CM I 1 -^ Tt< b- LO l> rH Tji rH rH CM CM CO CM O5 O O 00 Differential co _ y oJ S'o 10 rH rH CM CO * CO 00 O LO O O O rHCMCOrt* rH 411 ORIFICE CAPACITIES FOR GAS 9 CO Isll CD O O O rH rH OS CO T^ LO LO CO 00 OS rH OO O O O O b- i 1 CO O5 ^ CO 00 O LO ^ O i-H 00 CO O 00 00 b- O CM O CM O CO CM OO 00 O 00 rH d d d d co b- co ^ rH CM T^ CO rH rH rH rH 3 s rt 4! ED tf> s .0 LO 00 b- CM CM CM LO 00 CM b- ^ OO CO LO rH CD O CM 00 CO -^f Ills rH O5 LO 00 OS OS rH CM rH rH CO fi~ w ^ s 11 $ CM rH OO CM Tt< b- r-H i I i-H i-H O LO 00 CD O ^ 00 rH CM CM CM 00 ii b- b- 00 O rH !_, 7 t) * ^g 00 l> CO rH LO 00 rH -^ rH rH CM CM CO i-i 00 OO OS ^ rH 00 d d d d Tj< OS 00 b- LO LO CD b- l| o & S o 00 oo d r-i d LO b- 00 O rH rH rH rH 00 b- LO Tf CM CM CO 00 b-' id o o O Tt< rH 00 ^ Tf< LO LO s| S *s .5 00 ^^gg3 00 O CM 00 >tf' O CM OO CO OS OO CO 00 OS ^ CO 00^ s 1C co VH S .g O c^ OO^LOCO ooo2 00 O CO CO CO CO OS CM CM b- O5 O LO b- rH CO co S " 2 W | -S * H o "^ 'S ^ tt ~ 1 I LO i-H b- OS CC i rH i-H CM 00 ^ LO SKSS tf CM CM t> rH OO CO 00 i-H i-H rH i-H O5 Tf< LO CM CO OS CM CM CM CM O T3 OJ ^^ 53 r^ f 1 " i * P CM OS r-H b- CM OO OS CO 1 CM CM 00 "* CD b- 00 b-^ LO ^ LO CO b- S8S3 00 ^ CO OS CD 00 rH 00 -^ | 5 . rt ^ CD Tt< OS 00 00 b- LO CD MO 2 o*3 eo\ rH ^ b- O Tt< rH rH CM CM 00 LO O LO CM 00 ^ ^* CO -^ OS rH LO CO b- OS i-H rH i-H rH wig* II rH CD O O -^ O 00 LO 00 CM O O LO rH CD O 00 CM CM 00 00 rH i> CO b-' r* -^ LO CO id CM LO CD b- 00 05 O > * td o S S o r 1 ^ O Tt< b- b-^ OS O CM rH rH b- O 00 CM TH 06 d oo rH rH CM CM LO 05 00 LO %%%% LO LO CO b^ SI b- 00 b- CM T}< CO <* 05 00 rH OS OS "tf CO CM M , H W CO rH -^ O CM LO b- t 1 I 1 rH rH OS rH Tj< b- rH CM CM CM o ft CO TH LO Tt< CM CM rH CD O b- CM CM CO 00 ^SSS GOOs"ScO LOCbSS h^ oj f^ rt LO CM CO CO O * b- J W> O |s M\ CD O 00 00 rH CM CM CM 8i^8 ^b^ b- 00 00 LO 1 rH rH 00 rH O CM TH b^ rH rH rH rH CM CM b- CO CO rj< OS rH OO CM CM 00 00 OS ^^gE: CO ^f 00 rH 00 05 O CM I 1 rH > CS 2 ^ pq o rt\ ^ -^ O b- 00 O CM ^ rH rH rH O 00 O 00 b- O ^f CO rH CM CM CM 00 05 -rH O CO CD Tf< CO CO b- 00 if rH TH CO CO Tl< lO CO fc- O5 00 CM CO i 1 d co id b^. rH rH rH rH OS rH CO CM CM 00 CO CO ^ Tt* lO 00 Differential 3 *-> O aJ LO rH rH CM 00 ^ CO 00 O rH rH CM CO -^ rH 413 ORIFICE CAPACITIES FOR GAS s o fa Si. iff S.g o al * fgli- s ^2 LJ S IM T^ OS HH r *^ ,A 0) H O^S 1 O .S Wgl5 a| o o CO b- 05 00 CD CO rH CO O b- CM CM CO CO 3388 SS| 00 O5 LO 00 CO CD O5 rH rH i 1 rH CM b- O5 CO CO 00 CD O b- CO CO CM CO CO TH TH O rH LO CM rH CO CM b- CO CM LO rH rH CM CM CO 833 rH TH CO CO rH rH rH rH rH LO CM rH CO CM LO rH CD O CM CM CO CO TH co O5 CO rH O5 TH CO rH LO 05 TH CD CM rH TH CO TH O5* O5 rH CO TH rH rH rH CO rH O5 O5 TH CO rH lO O5 CO rH CM CM CM CO CO CM O CO CM CM LO l> rH rH rH rH CM 10 TH O CD CM CM 00 00* b-TH i 1 rH d co' CM' id TH LO b- rH TH b- rH rH CM CM CM O CM rH CO 05 CO TH CM LO CO CO 10 O CM TH b- rH rH rH rH O5 C^J ^* 00 rH CM CM CM 00-38 gg| CM rH CO O2 CO CM TH b- 05 CM rH rH rH lt CM rH 05 TH O rH O CO 00 LO CM rH CM LO CO 05' rH TH CD CO 05 CM 10 rH CO TH O CM CM rH O5 TH O rH O CM CO CO TH LO CO b- CO 0:1 rH rH I 1 rH LO 05 rH CM 05 TH 00 CM TH O CO CO 00 O * CO b- O5 rH rH CM TH LO CO rH rH r 1 rH CM CM CM CO O O 00 LO TH LO lO CO O5 rH CM O5 TH b- O5 rH CM TH I I rH i 1 rH 00 CM 05 CM LO LO 10 rH CO 05 rH TH b- 00 g TH LO CO b- 00 O rH CM TH CO O5 CM 00 rHrHCMCM CM O5 lO rH CO 00 TH LO CO CM O5 CM LO CO b- 00 O i I i 1 rH O5 00 LO 00 CO b- CD rH CO rH LO TH b- CO O rH O5 6 CO CO TH LO CO b- CO 05 rH rH CM LO b- rH rH rH rH CM CM CO CO CO SSg^ o OOLOOO b- TH O rH rH rH O5 b- CM CO b- b- CM b- 00 J3 CM CO TH TH LO CD b- CO O5 rH CM LO i 1 i I r 1 rH CM CM CM LO O O5 b- TH CO TH TH lO CD 00 O CO TH CO b- CM LO b-' O5 TH CM LO CO CD CM CM CO 00 TH C? CO O5 O CM CO O5 CO CO --i i-i CM' CM CO TH 05 rH CM CO O5 CO CO CO* CO TH rH CO CO 05 LO CD l> CO CO CO CD CO O CM TH CD O5 O CM CD TH CM CM lO CO CM rH rH rH CM CD CD CM rH LOOOrHCO CM CM CO CO TH LO O 05 b- O TH TH id i> rH 05 TH CO 00 05 rH CM rH rH CO rH i 1 CD CD id co' CM LO co rH rH CM CM CM V 00 O 00 O5 05 CM CO CO LOGO 05 CD O5 rH CO b- O5 CO b- O b- CO TH CM CO b- CO O CO 05 10 00 rH i 1 i 1 rH rH CM CM CM CO CO TH LO CD b- CO 05 CM CO CD O5 rH rH rH rH rH CM N^ rH CO rH TH b- CO O CM CO O LO CM TH COb-0 CO b- O rH CM b- CM O5 10 LO TH rH CO rH TH CO O rH rH rH rH rH rH CM CM CM CO CO TH lO CO b- CO O CM TH CD rH rH rH rH r^ O rH O CO LO CO b- CO 8383 CO CO CO CO LO O5 CM b- S $ T? rH O CO O rH rH CO CO TH TH CO b-' 00 O rH Differential || .So O LO O O rH rH CM CO w? IO rH i-i CM CO TH CO X O rH 10 O O O O rH CM CO TH lO 414 ORIFICE C A P A C I T I E S F O R GAS Table 145 10 INCH LINE HOURLY CAPACITIES OF ORIFICES PRESSURE 10 LB. Specific Gravity .600 Pressure Connections at Flange. Pressure Base 4 oz. Base and Flowing Temperature 60 deg. fahr. Atmospheric Pressure 14.4 Ib. All capacities expressed in thousands of cubic feet. Diameter of Orifice in Inches b- -tf 00 O3 O3 83833 b- -tf O O 10 CO b- 00 2g 00 O3 IO 00 rH O3 O3 O3 00 O3 O3 O O rf O O5 b- -* CO ^ -^ lO CO b- 1C b- .03 CD 83 8 83 3' 05 CD 03 J> CO CO -^ oo co t~ o CO -* r}< lO rH IO b- CD CO b- 00 O o13 i 1 rH i 1 i 1 CO b- 00 00 00 O3 O3 CO CO ^ CD O CO CO b- SSolol O5 J> rH O3 rH IO O5 kO CO CO CO ^ O O3 rH b- lO CO b- 00 3cS3 rH i 1 rH rH CD CO b- 05 b- O5 O3 fc- rH IO rH O3 (53 OO CO \^ 10 O O Tf CD CO CO 00 O3 i 1 i 1 rH OI rH rH O5 O5 rH CO O5 rH CD O3 O3 CO CO rH O 00 rH Tf IO IO b- O3 rH b- O 00 O rH 00 O T^ CD 1 rH CD 00 O3 CD O5 10 lO O5 O5 O3 O 03 Tf 00 I I I 1 I 1 r ( i 1 IO O5 00 oioioliS O3 00 rH CO O b- 00 CO Tf< -rH 10 CO 00 0> O rH O5 O5 O3 rH IO 03 r^ oo rH CO rH rH rH O3 O3 r * iO -tf O b- 00 O 03 TJH rH rH rH O5 O5 t- O5 CO 00 O CO rH rH O3 O3 CO 00 00 CO CD O3 b- CD O3 OO CO ^ 88 ^ O b- O5 O5 003^COOO * CO rH ri< IO OO 00 CO 00 O b- b- rj< o CO 00 O5 rH rH CO Tt< CO 00 i 1 rH rH rH rH IO O5.CO 03 03 03 CO O3 rH O5 CO T* 10 10 CO rH Tf< IO CO 00 00 O5 rH CO -* i 1 rH i 1 ^ 00 rH O3 O3 00 03 00 ^ ^ rH b- b- 00 rH CO Tj< lO CD b- 00 O rH 03 00 05 O rH rlrHSg oloSc^c^ IO CO lO lO CO r^ lO CO b- 00 ^ 01 rH 00 "^ -^ CO O t- 05 O5 rH O i 1 00 03O CO O5 <* oo' i-i rH 03 03 CO CO CO od TJ<' ^ co o CO TH IO CO b- CO CO "tf IO CO i> 1> 00 05 03 T}< b- rH rH rH 03 r-l O5 C5 rH CD rH CO IO 03 00 -^ Tt 03 rH b- 00 10 O3 CO rH O5 O5 rH O3 CO 00 Tt< 10 10 co t- 00 O rH rJH rH rH rH si^ rH CO 10 03 00 CO CO -^ lO lO O3 rH O5 00 IO rH 10 05 CO O3' O3 O3 CO 03 b- O3 O Tt< -* 10 CO b- (M-^ 10 CO 00 05 rH 1 1 CO 00 00 rH CO CO 00 r-i. rH rH rH O3 05 00 10 rH rH IO O5 CO O3 b- 030^00^^ 03 88888 r-i 03 03 03 00 t^ O b- CO 00 ^ ^ O3 Tt< Tj< rH IO CO t> O5 10 05 00 CO O 03 T^ CO rH rH rH rH CO 10 00 03 rH O3 O3 O3 CO 00 rH 00 CO rH rH O3 lO 00 O3 r-i rH rH 03 SSrHcS OOb-0 rH 05 TH 00 CD rH rH CO CD id oo' 03 'id oo rH rH O3 O3 O3 O3 O3 CO CO ri< IO 10 b- 00 O5 rH O3 rH rH ^ r ( CO "tf O3 O3 O5 rH CO CO So88c2 rH OX O3 O3 LO rH b- O5 CD rH i 1 O3 CO ^' IO' O5 O3 CO CO kO 1> 00 05 ^ 03 03 b- 05 rH CO CD 00 O rH rH rH rH 03 ^ i 1 lO O O3 CO CD 00 O5 rH i-H O CD O Tt< co^coS rH rH i 1 rH ^S^ O3 O3 0300 O3 rH O 00 10 Tji iO id cd O O3 CO O CD 00 O5 i I CO rj< rH rH rH Differential in Inches of Water 2288 10 rH r-i O3 00 * co oo o rH s^i^g 415 ORIFICE CAPACITIES FOR GAS s CO CO CS 8 I s J r i ::< ol O fg WoJH ee Iv I g O \P* 1 00 SO 00 CO i^S 1 CO J> 00 OS * 1 l> i t i ( lO O 00 iO 00 i 1 r-t i 1 i 1 sill Ilii lill J> CO 00 OS OS IO CO CO i> 00 OS CO -^ 00 O CM iO 00 00 I-H f-i t- i i m oo i-H CM CM CM 5S ssss \QOOCM Tj^ t^- O 00 1111 i co LO co LO iO CO t> CO OS Tf LO l> CM CO rj< CO *tf rj< LO o co m ^ CO t> 00 O CM ^ t- OS i-H rH rH r 1 CM 00 OS OS CO CO CM t> CM CM CO CO 111 ^ 10 OS LO 00 CO d Tt< l> CO CO 00 CO r^ 00 oo o os m TjH CO CO 00 OS CM 00 iO i t i-H r-t OS CO t^ OS 00 rH CO O rH CM CM CO CO CO Tf* Tf 10 O O > ^ id 06 d id CM CM 00 CO m in OS 00 CO OS CO Tt< OS O CO b- 00 O CM rH CO OS CM ^ t- OS Ills .s ^ % 00 CO CO CO OS CO 00 CO CO 00 CO OS t- OS CM * IO J> OS CM i 1 r-H i 1 CM Tt< o m oo CM 00 CO ^ O < ( O OS m co i> i> CO r-H CO 00 os I-H co in r 1 rH i 1 i 1 rH 00 OS O OS CO CD CO i I CM CM CO rH {> 00 CO TH O co ^ in co rt< in rf ci t> 00 O CM in 00 O rH Ot) Tj< i> OS o Wr OJ OS 05 OS CO 00 OS O CM O CM OS CO r^ t> OS TjH rH Ti< J> TH CM CO CO ^ ** CO t- OS LO CO f> 00 OS OS CO O OS O CM T}< 0) S N* 1 & lO CO i 1 CO t- 00 OS O I 1 J> 10 J> Tj< CO t- Tj CO fc- i-H -^ CO O r-l r-l nH CM CO 00 00 t^* CM CM CO 00 10 co m m rt< m co t- 00 rH CO t- 00 OS O rH ^ 0] r-H OS LO i> CO CO J> 00 t> OS t- 00 OS i-H CO CO i-H i 1 i I ^ 00 iO t- OS CO t> C5 I-H CM CM CO co in t- CO CO rH co.Tf in co os LO t> t-' CO t> 00 OS ^ CM O CO rH rH kO iO CO t> OS t- CM J> J> OS r-H 00 I 1 1 1 00 T^ T^ O in os CM m r-l rH CM CM CD Tf" CO O iO 00 O 00 OO -^ LO CO rH rH OS lO CO I> i> N m i i co OS ^ 00 CO CO Tf -^ LO CM CO 00 00 CO t- 00 O m co co t- CM m J> os CM OS CM m Tt< l> T^ OS CM CM CO CO rH 00 ^ 00 CO CM ^ "tfi LO CO x \^* \ r 1 rH t- OS CO O CO CO CM 00 CO CO ^ 00 00 t> CM ^ iO CO CO m t~ in rH os I-H oo m Tj< CO rH rH CO rH CO O rH CM CM 00 t- OS CO O CO CO CM CO CO CO -^ -^ \^ 1 I r-t CM CM CM CO i i O CO m co os i CO ^ Tf CO O CO OS rH l> CO OS rH rH CO t- CM CM CO 10 OS CM rH i-H rH CM 00 CM <* rH CM CM CO 00 \* I 1 Tt< CO OS 00 iO t- 00 I-H r-l i-H r-1 C\j ^ OS kO 00 T^ OS -^ CM CM CM 00 ^ 00 O OS t> rP CO CO t- LO OS ^ rH os d oo id i-H rH rH oo OS oo n< 1> CO rH ! T}< rHrHCMCM Differential in Inches of Water ss IO i-H i-H CM CO TJH CO 00 O r t LO O O O rH CM OO ^ LO CO 00 O 416 ORIFICE CAPACITIES FOR GAS pa 5 CO CO w g CO .a o W 1 3 a 13 5 I j 69 s .a .a | H S-a-d 03 ^H O Q} <-> v *d cu ill $ n 2 s T^ lO O 00 00 CO OS CO rH rH rH CM fill Ills OS O CM OO rH rH rH b- rH CO b- CM rH CO lO OS rH i 1 rH rH CQ t> i-H lO CVi C^J CO 00 O CO O O CO OS i-H O T^ Tj< CO b- 00 CO OS rH b" 00 OS rH i 1 co CM CM O OS OS rH CO lO rH rH .rH CO rH O O lO rH O 00 CO ^ LO kO gll CO rH rH rH rH CM CM CM CO Tf T^ O O O O CO 00 b- lO LO LO CO b- 10 rH lO b- CO CO b- 00 O rH CM kO t2 OS rH rH rH rH b- -^ lO b- OO b- 00 00 CM CM OO OO 00 b- iO rH 10 O rH O CO LO CO b- 00 OS rH O b- OS CM ^ LO rH rH rH CM CM CM Tl< OS CM b- rH rH CM CM OO rH Tt< Tfl O {J 1 ^H O 00 CO OS <* <* 10 co b- OS rH CM rH rH CO b- b- O LO b- rH LO rH rH CM CM llil s <* T* CO CO rH 00 Tt< kO 00 OO -^ lO rH CM rH CO OS CM ^ 00 rH CM CM CM CO eg ^ o O -^ os co ^ OS 00 rH CM CM 00 T^ 00 03 00 CO Tt< 10 CO b- CO b- rH CM OS O CO lO rH rH rH O CO lO O b- 00 rH -^ rH rH CM CM o S-, <1J CO b- O b- b- rH lO O rH CM CM CO 10 00 O CO CO rl< LO lO OS OS b-' CM CO b- OS rH i 1 IO b-' 00 CO CM CO LO b- D 6 ^ .2 OS rH 00 rH rH b- CM CM 00 H^ rH OS CO O LO CM OS OO 00 ^ ^ IO rH O 00 iO CO b- b- rH O CO 10 -tf CO b-^ 00 O CM ^ b^ 05 rH rH i 1 rH CM 00 OS OS CO CO CM l> CM CM 00 00 T* 10 rH Tt< Ttf CM CO TF id co i> X 00 T^ 05 00 O CM 00 rH rH rH O b- rH 00 b- OS ^ b- r-irHCMCM rH rH Tt< rH TH OS Tji CO CO CO ^ \a| Ob^COCO rH 10 b- b- OS b- 00 * CO b- - O -^ i-H i-H CM CM CO O -^ CM O rH rH CO CO 05 O rH CM "tf COCM-^rH CM-^OOt- O5 r- TJ< a -I .-1 r-< CM CMCMOO5 T^iOOO COrH O kO CO rH J> CO O5 CM OrHt-rH rHCOCOCM TtO5'cM r>rHCO^ rHrHrHCM CMCOCO^ CM CO CO O5 kd co t- 06 COCOCOCO O5OCMCO r^O5rH rH rH rH rH rH CM CM **% V Cl CO J|5! s- 5 CO * rH CM CO* Tt< kO O rH J> rH CO CO O CO CO CM CM CO rH'wco ^coooo joooo oooo 418 ORIFICE CAPACITIES FOR GAS a |i< 3i = a 11 O S 1 o M" 5 ! 1 S o i I Stui* P" r-H g Hi *H. oS M o u H O M O J> 00 O 000 rH Ttf lO O b- Oi rH 00 05 CO O5 CM i 1 i 1 CM O b- 00 O CM rH CO ^ CAJ lO 1C CO b- rHO lOrHCOCM COb-lO OOO rHTHCOOO CMlOrH i-l rH rH rH rH CQ CM CO rH CM~ ^* b O.lO rH rH rH rH CM CM O5 CO CM ' CM O5 H O5 CO O rH b- rH T^ CO 05 is o c OJ CO CO rH C\J C\J rH 00 CM CO b- b- CO rH 00 O CM 10 OCMiO b-rH-^b- CO rHrHrH rHCMCMCM CO OJ 00 00 b- co co b- oo ^ O5 rH rH CO 1> 05 rH 00 t- 00 O Oi LO LO LO 00 Oi O LO Oi CM t- rH CO lO rH rH CM CM CO CO rH O O O O rH l>- rH Oi i> CO O rH Oi ?rH 28 CQ *& LO iO J> rH Oi O O O rH t>05CO CO CO CM ^ CO l> rH -^ t- rH CM CM CM 000 rH * t^ CD CO t~ O O rH 00 CO CO rH rH rH rH CM CM CM l> O CM 00 rH rt< r)< iO CO CM CO CM CO O rH CO rH CD CO CO CD 00 CM CD CM C\j o J> co co CO CO -^ lO r-i 10 i> CO J> CO CO CO Oi rH CO t> O rH rH rH CM CM CM CO 8 CM Oi O 00 CO Oi CO iO CO CM CO il CM CM 'CO CO CO CM CM r-i CO T^LOCDCD rH CD rH CO LO CO Oi rH ^ iO Z> CO C^J CO CO ^ CO IO O CM ^ CO O LO OS CM CM CM CM CO O CO t- CO T}< Tj< LO CD t- r)< Oi CO l> Oi O CO CO ^ CM J> rH O Oi LO CD CO CO CD CD CO lO CO l> O5 J> rH rH Oi O CO LO CO J> Oi CO CO S CM CM CO 420 ORIFICE CAPACITIES FOR GAS PQ ^ b- 00 00 CO CO r-M 4) v* LO rH rH rH (M LO O CO b- rj< O rf< 00 CM CO CO 00 b- LO b- b- 00 OS O CM 0) 1 LO oioi^bt rH rH rH 00 CM O CO rH CM CM CO 00 00 O O 00 rH rH CO CO rH LO CO S' d o' d b- OS OS b- b- 00 OS .H a CO o S* o o a * rH rH S2ll rH CO O LO CO O CO CO rH LO 0000 CO rH rH OS LO CO b- b- HH t .S * C\j CD 00 00 CD b- 00 O rH i 1 rH rH rH rH b- rH OS CM CM CO CO rH CO O O rH 00 CDlW rH rH LO CD O S d jg ^ d o 6 CO 00 00 b- OJ rf< lO CO 00 LO b- LO rH OS rH 00 LO i I i 1 r I rH CO rH rH 111 Ud iH i M 1 ja o )H OJ CO LO CO O rH 00 rH LO CO O CO OS rH b- 00 OS rH rH CO LO CM CM 00 b- OS CM rH rH rH CM 00 CM rH O rH b- rH LO CM CM 00 00 ,0 r ( 5 ^ d rH rH b- H | s 03 I OS CO rH rH CM CO r}< LO OS CM CO 00 LOb-OOOS rH 00 CO 00 rH rH rH rH 1111 00 b- 00 rH rH rH b- CO 00 O 00 2 * rH 00 O CM LO rH rH rH rH CM 'CM CM %%%$> gg88 r*H S r-H 'o S rH rH CO LO CO b^ 00 O rH rH 00 rH CM CM rH b-' OS rH rH rH rH LO rH CM OO os os S Differential C/5 ^ -H ^ So LO rH rH CM CO rH CO 00 O rH S88S LO CO 00 O rH 421 ORIFICE CAPACITIES FOR GAS s CO 8 .o co PQ ~ W 3 S IL CO t= t^ s^ o s 1 o CJ -5 S < IS a l S g jvfti O S _o S II o w w ]Z <) S 'o 3 s, r 43 +J 2 flrS l 5 ^ g.i o iO t^ "* b- CO (M CO CO O 1> CD CO CO^ LO d Oi CM o CD t>- r l CM b- Tf 00 CM lO i-f rH CM CM CO LO O O Tt< rH t> -^ LO LO o o o o o o o rH OS LO 00 rH CM f I 00 OS rH CM ^ CD 00 ;CO rH CD t CO rH CO ^ ^* LO CO 00 i I l> CO rH O O O OS CO b- CO CO LO lO ; CM CO CO -^ LO CO > 1-HrHrH rHCMCMCO COrt "tf CD J> LO CO t- rH rH > OS O CO LO 00 Tt< CO S,CO rH t> CO Tj< -^ C5 O O OS 00 LO LO CO t> COrHCMO COCM-^CO LOOSOOb- LOJ>COO rHT^COOO CM LO rH CD rH 1-HrHrHrH CMCMCOCO o os o rH T^ (SJ T}< ^ LO CMCMOCO LOT^O-^ T^LOCOt- OOOCMCO .OS ^* J> CM CO ^ O5 CM g^88S 2 OS -H^ LO CM co os CM CM CM CM' OS rH J> CM CO 00 -^ CO CD CO rH rH rH CM CO LO T^ O t> 00 O CM Tj< CD -^ O5 ^' t> O .^" r-l nH.CM CM to O O " O CO LO 00 CM O O LO COLOOO rHCOOCO rHi>OOJ> ;H rH rH CM CM CO CO T^ ^ LO CO t>OOOCM LOOSCOLO 10 i-J CM CO O O O O LO CO 00 O 422 ORIFICE CAPACITIES FOR GAS C/2 3 x5 S!i ffi E2 a I! 3 I 5 o O s ft I 10 O S 1 I O r i tv **k^ WJ rH rH i-H i-H CM 000 CO b- 00 Oi rH CO t- iO O *O (M (M i-H rH Oi CO rH CO ^ CM t rH "tfkOCOCO OOOirHCO * CO o oo o "tf CO O ^t* Oi i I CM CM CM iO Oi t 00 CO t- CO CO Oi CO i 1 i-H i 1 CM ^* kO t CO O O O O O ^ CO 00 CO CO rH kO b b- CMCOCO-^ kOCOl>00 O5 O CO lO Oi i-H rH rH i I CMCM'COCO O Oi rH 00 CO CM O O OO <** 'Q.rl "3 ^c-iQO OkO C43 -M t- rH rH rH rH CM/CM CM COCOT^lO COCOt- i-H i-H rH rH CM O 00 rj< Oi 00 b- ' CM CO kO 00 rH CO rH rH rH rH CM CM 00 CM lO 00 CO 00 OJ LO CO kO O i-H CO rH CO CO - OirH-^b- i-HrHrHrH rHCMCMCM rH i-H rH rH i-H CM lO CM CO CO CO C3 CO 00 rH CVJ CM COCO CM T^ > r-H i-H i I rH CM CO rH 00 rH 00 Oi O CM rHrHCMCO T^COOOO o o o o kOCOOOO 423 ORIFICE CAPACITIES ORIFICE CAPACITY DIAGRAMS The orifice capacity diagrams shown on Pages 426 and 427 will be found useful in determining the proper size of orifice to be used where the orifice in the line is indicating too low or too high a differential, and in cases where the flow is to be increased or decreased. These diagrams can be used to ad- vantage where the pressure remains practically the same, or where it does not vary over a limit of 20 per cent. As an example, we will assume that a 6 inch line contains a 3 inch orifice where the differential pressure averages 3 inches on a 50 inch gauge. In order to obtain more accurate results the differential should average around 20 inches. By drawing a line from coefficient line C where the size of orifice is in- dicated, to 3 inch differential on differential line D the inter- section will be about 14,200 on line Q. Then by drawing a line from 20 inch differential at line D through the intersection of the first line and line Q until the second line intersects with line C it will be noted that the nearest size of orifice for a 6 inch line is 2 inches so that a Q" X 2" orifice at 20 inches differ- ential will have approximately the same capacity per hour at a certain pressure as a 3 inch orifice at 3 inches differential. As a further example, assume that a 6" X 1M" orifice with connections at the Flange produces a differential of 10 inches. By drawing a line from line C to line D at the inter- section on line Q is approximately 8000. We will assume that the flow through the line was 20,000 cu. ft. per hour and that the proposed flow is to be 50,000 cu. ft. per hour at approximately the same pressure. Therefore the increase in flow will be 2J/2 times so that on the diagram we would draw a line from an average differential 20 inches, on line D, through 20,000 on line Q, (20,000 = 2^X8,000) to inter- section with line C, which indicates an orifice 6' / X2^' / . The quantities on line Q are relative only and do not refer to cu. ft., gallons or any particular units. These diagrams may also be used for water or oil by always re- 424 ORIFICE CAPACITIES membering that the numbers shown along the line Q are relative quantities only. In the same manner as in the first example if a 6 inch line contains a 3 inch orifice measuring oil, water or steam at 3 inches and it is desired to increase the average differential to 20 inches, the size of the new orifice would be 6"X2". If the proposed flow and differential are both increased as in the second example, the same relative sizes of orifice will be used, or the 6"X1%" orifice will be increased to a 6"X23/g" orifice. Either of the diagrams may be used for determining the proper size of orifice on account of the change of quantity or change of differential. Care should be used that the diagram for the proper pressure connections shall be used. INFORMATION TO BE FURNISHED WHEN ORDER- ING ORIFICE METERS AND DIFFERENTIAL GAUGES Measurement of Gas and Air. 1 . Estimate of maximum rate of flow in cu. ft. per hour. 2. Estimate of minimum rate of flow in cu. ft. per hour. 3. Approximate maximum line pressure in Ib. per sq. in. 4. Approximate minimum line pressure in Ib. per sq. in. 5. Specific Gravity of gas (Air = 1.00). 6. Internal diameter of pipe line, if not standard or if it is 12 inches or larger, give actual inside diameter. 7. Pressure Base at which gas is to be measured. Measurement of Steam 1. Estimate of maximum rate of flow in pounds or horse power per hour. 2. Estimate of minimum rate of flow in pounds or horse power per hour. 3. Approximate maximum line pressure in pounds per square inch. 425 ORIFICE CAPACITIES \| "X "j^-*^ o r.*aig 3 ???? 7 J^^-Q, \ \ \ \ \ \ \ \ \ \ I oioaoo o o ooooo o o oooo o oooo -oooo ooooo oo oooo ooooo. In^SISSsilSiB o, 1 / i . D/ameter6of0r/f/ces- inches ^ / * *o ^| - J 5JI / 1 3 J 1 "4SI n 1 V "*! "5? ^ I ij "^l ' V "J? Sf !L m :1? h^* ^~^'V ! ^"i ">| & ' ^ M -Wl 5j "|| n S V -s 1 "^f "^ *> "^ ^ "^ "* "J 1 ^i ^ VB 1 ^ "^ ' 1? * Vs^j ! > i i i "t* * -, "jj| ")| Jj'jl ^?| ^J| ^i ^| H I?*' | "N- ^1 | > I \ "J? OOOOO OOOOO 00000/0 OOOOO OOOOO OOOOO o 0.0000 0000 o NV>BO 5 SSSSo ooooo SnwS 3 ^ o5oo ooooo- SnSSS S oioo-irio S SooS S?2So o SSSS o oooS ^ 1 1 1 1 1 i 1 1 1 T? i 1 1 1 1 1 1 1 MI I i i 1 1 1 i 1 1 K i i i i I i 1 1 1 1 i i 1 1 1 i i i M i i i 1 1 1 r\ K ' ^ ^ ' / 5 / / o / / 1 / ' / / / / * / / s / / / / ^ 1 1 j/ometers of0r/f/ces-fncftes ^ J / .*> ^ .$ -3? ,vt> 35- rij ^ ^ s H raa H $ i w *& * ! ~ ! y- H3[ 33l3233^3SS c '-> ^j ^ jg -JP S^glSMlO 'P "II flj "i PI W^M^1*II "I ^ "^ ^ "55* "5* -^ ^ Sffiitj * 33 OO ^. ^vi ,^5t > -Sjt * * if -ffl -.