GIFT OF LFWARY , PR A C TIC A L INS TR UC TION FOR YO UNG ENGINEERS AND STEAM USERS. BY Egbert Pomeroy Watson, Editor and Proprietor of THE ENGINEER. AUTHOR OF Modern Practice of American Machinists and Engineers -Manual of the Hand Lathe The Professor in the Machine Shop. Etc., etc. Copyright, March, 1892. 150 NASSAU STREET, NEW YORK. 1892: Prefaces have gone out of fashion. They are usually excuses, or explanations, or apologies, or something akin, for having written what follows them. This little book needs no preface, but here is one and a dedication as well, for in this work I have endeavored to serve young American Engineers who have taken to the busi- ness seriously by mentioning a few troubles they are likely to encounter, but it is only mention, for the one thing which can not be imparted is experience. Time, study, and practice alone can give it. No man was ever , made an en^ipecr |>y a book or by rules, but every en- ,ginee,r 'jAult&rxDvr^he first principles and traditions of .ty Jxiaiwefs. I Tbe inexperienced will find a few of :thecrttferein." : * * This little book is dedicated to American Engineers, the men who have always helped me on my way and who have always kept faith with me; who have always held out the right hand of fellowship to me as man and boy, by their sincere friend and well wisher. EGBERT POMEROY WATSON, February i, 1892. 150 NASSAU STREET, N. Y. GIFT OF ENGINEERING LFBRAIIT IKDRX. CHAPTER I. Cleaning the Boiler PAGE l Removing Scale- 5 CHAPTER II. Using Scale Preventers 7 Oil in Boilers --- 9 Braces and Stays -- 9 CHAPTER III. Mud Drums and Feed Pipe --- 11 Boiler Fittings ---- 13 CHAPTER IV. Grate Bars and Tubes - 15 Bridge Walls---- - 17 The Slide Valve Throttling Engine - 18 CHAPTER V. The Piston --- 22 The Slide Valve---- - 24 CHAPTER VI. Testing the Valve with Relation to the Ports 27 Defects of the Slide Valve - 30 CHAPTER VII. Lap and Lead -- 33 The Pressure on a Slide Valve 34 Stem Connections to the Valve 36 CHAPTER VIII. Valves off their Seats 40 Valve Stem Guides - 41 Governors 42 Running with the Sun -- -- 44 865694 CHAPTER IX. Eccentrics and Connections 46 The Crank Pin -- --- 48 Brass Boxes V 51 Bearing on Pins 53 Fitting Brasses to Bearings 55 CHAPTER X. Adjustment of Bearings -- 57 The Valve and Gearing -- 59 CHAPTER XI. Setting Eccentrics 65 The Actual Operation -- 67 CHAPTER XII. Return Crank Motion - 74 Pounding 75 The Connections : - 77 Lining Up Engines 82 CHAPTER XIII. MakingJoints 88 CHAPTER XIV. Condensing Engines 93 CHAPTER XV. Torricelli's Vacuum loo Proof of Atmospheric Pressure - - 101 No Power in a Vacuum --- 101 Pumps - 105 CHAPTER XVI. Supporting a Water Column by the Atmosphere 107 CHAPTER XVII. Starting a New Plant 114 CHAPTER XVIII. The Highest Qualities Demanded - - 122 The Man Himself the Factor - - 123 Lastly - 124 HOW TO RUN ENGINES .MTBMS, >, CHAPTER I. The first thing to be done upon taking charge of an engine and boiler, new or old, is to examine the boiler thoroughly. No matter whether it has just come from the shop, or has been run for years, take off the man-hole plate and go inside yourself with a hand-lamp ; after you are in look at all the water spaces, and see if they are clean, that is, without rubbish or dirt of any kind. Even new boilers are not free from this. There are various irresponsible persons about boiler shops who are not as careful as they should be, and it will be the exception rather than otherwise if you do not find a lot ot things which are better out of the boiler than in it. In large boilers rivet kegs are often taken in to sit upon, and are not always taken out again ; the staves are thrown down in the water space, from whence they will float out and get in the steam pipes by some mysterious happening. The water line is not so high as the steam pipe, by any means, but the staves get there somehow ; so do bunches of waste, etc. Everything of any kind should be cleaned out of the boiler before water is run : . . > e necessary to take \ ::':$ *Ke*3e\\trtand-hole plates, and with a small hooked rod dislodge everything that is loose in the boiler. Spare no pains in this work, for it will be labor and money saved in future. When the boiler is thoroughly clean you can put the plates in again, but before doing this rub the gaskets thoroughly with plumbago, and they will not adhere to the plate where exposed to heat. This is a saving of time and gaskets in breaking joints in future. The old way of making joints upon hand-hole plates, with hemp gaskets slushed with white lead, has gone out of use, having been superseded by rubber gaskets made for the purpose. If you are remote from a city, however, and cannot get a rubber gasket, you can make a hemp gasket which will answer all purposes. Jute is the best material for this job if it can be had, but you are quite as likely to be out of jute as out of rubber gaskets, and if you have neither you can get a clothesline most anywhere. Unlay this and take the twist out of it ; beat it with a fiat stick so as to reduce it to its original fiber ; then braid it up again of the proper size for the job in hand. Find the right length for the gasket, and join the ends so as to form a ring of the proper size that will fit the plate ac- 3 curately : it should go on so tight that you have to force it over the flange of the plate. Cover this gasket thoroughly with white lead, and then put it in its place. It will be abso- lutely tight if the work has been properly done. CLEANING THE BOILER. We have been assuming that the boiler you have taken charge of is a new one, without scale, but it it is an old one there is likely to be a quantity of scale and dirt, which must be taken out at once. The way to do this is to us the best tools you can get hold of, or con- trive for the purpose. The place to look for dirt and deposits from the feed water is in the bottom of the boiler furthest from the entrance of the feed water, and in the parts that are the coolest, if there are any, when the steam is on. In a return tubular boiler this is generally in the smoke-box end, which is not so hot as the fire-box end; the quantity of rubbish which ac- cumulates in a neglected boiler is astonishing, and you must not be surprised if you have to remove wheelbarrow loads. This dirt comes from the solid matter in the water, both that which is carried in mechanically from turbid supplies, and that which is held in suspension until set free by heat. Every gallon has a cer- tain amount, and as many gallons are evapor- ated daily, unless removed weekly it soon makes a wheelbarrow load. This dirt, by backing up against the flue sheet, deprives the ends of the tubes of water* which not only steals part of the heating surface, but destroys the ends of the tubes and flue-sheet by corro- sion and over heating, so that it is only a ques- tion of time when the boiler will be practically useless. If the lower course of the tube-ends in the smokebox leak, be sure that they have been abused in the manner stated. You will probably find that they will leak after dirt has been cleaned out. In that case the tubes must be re-expanded, and to do this a boiler maker must be called in. Do not, upon any con- sideration, try to tinker them up with a ham- mer yourself. You will only make a bad mat- ter worse, and set other tubes to leaking which were tight. Having taken out what may be called the ''loose dirt," though some ot it is very far from being loose, you will find another job in front of you, and that is to get out the dirt which is fast. In other words, the scale. This is actual stone, .artificially formed within the boiler from the working of it. It differs in character with the kind of water used. If it is hard water, so-called, it will be limestone scale ; if soft water, it will be sul- phate of magnesia and soda scale ; either one of them is bad enough, so far as the boiler is 5 concerned, and must be removed absolutely if there is to be any economy. REMOVING SCALE. There is a way to do this which we have practiced with success, and that is to run the boiler full of water up to the third gauge and then put in a quantity of a scale preventive. Of these there are numbers in market, but we do not name any one as the best. Doubtless none of them are wholly useless, though some of them are inert or do not act. You will have to find out by experience which one serves your purpose. Sometimes caustic potash answers a very good purpose. This when the scale is chiefly mud with sulphate of soda and magnesia combined. Caustic potash is the concentrated lye sold in grocery stores, but if wanted in large quantities should be purchased of wholesale druggists. To use it, dissolve it in a barrel of water, say 40 pounds to the bar- re], and pour it into the boiler. This is about one-sixth of a pound of potash to the pound of water, and is strong enough for the purpose. After the purger is in the boiler build a light fire and heat the water to boiling point, and then haul the fire and let the contents stand. It is better to do this on Saturday night, if pos- sible, leaving the water in the boiler until Mon- day morning ; you should then get up steam to, say, five or ten pounds pressure on the same water, haul the fire all out, and blow the boiler down. You will, in the majority of cases, find the boiler thoroughly clean, except for chunks of scale which cannot go through the blow-cock, and which must be taken out through the hand-holes. CAUTION. In handling caustic potash the utmost care must be used. It is truly caustic, or burning, and if a portion gets in the eyes it will cause serious trouble. The same is true of sores on the hands. Handle it with gloves ; treat it very respectfully. CHAPTER II. USING SCALE PREVENTERS. If caustic potash cannot be had, a substitute may be found, in rural districts, in slippery elm bark. This is not at all caustic, but quite the reverse, being demulcent in character. How it acts we do not know ; but that it has a certain efficiency we do know, because we have cleaned boilers thoroughly with it. It makes little difference how much is used, put it in the boiler and let it stay there for a week, and there will be a benefit from its use. These purgers just named are only of service where the scale is soft ; for hard scale a differ- ent one must be used, and to attack lime scale it should be of an acid character, for lime is alkaline, and its antidote is an acid. But just here trouble is likely to ensue in the hands of an inexperienced person. A good many will exclaim loudly against using an acid purger in a boiler, arguing that it will destroy the boiler as well, and that very soon. Some have shown us pieces of iron, that they immersed in certain boiler purgers, that were badly corroded. This is very likely, but it so happens that no boiler purger is used in that way. The purger is largely diluted with water, and acts very slowly upon the iron. It attacks the scale first, be- cause it has the greatest affinity, or liking, for it ; after that it goes for the boiler plates ; but there are no after effects ot this character from a boiler purger, because it is no longer in the boiler when the scale is removed, and if a boiler is thoroughly washed out there is no danger to it from the use of a strong purge. There is very great danger from the presence of heavy lime stone scale, and since nothing but a purger with an acid reaction will remove it, we do not fear to use it ourselves. Some engineers have shown us boilers from which the scale was removed which had the plates badly corroded. This action was attributed to the use of the purge, when it was, in fact, caused by the scale itself. The corrosion was going on all the time underneath the scale, and when it was removed the injury it caused was manifest. Ot two evils we are taught to choose the least, and in this case the use of a strong boiler purger is less than the injury and loss of fuel caused by scale. Get that out first, thoroughly clean the boiler after of all traces of the purge, and there will be no trouble aris- ing from its use. It is understood, of course, that alter the use of any boiler purge that the hand-hole plates must be taken off and the boiler cleaned out by hand, washed with a hose, and then filled up and blown out again before steam is raised. There is no middle ground or half-way measures possible in deal- ing with a dirty steam boiler. Get down to the naked iron and keep it so, inside and out, and the boiler twenty years old will steam as freely as one just out of the shop. OIL IN BOILERS. Do not upon any account put crude oil or any other kind of grease in a steam boiler. It generally gets in fast enough through the feed water where open heaters are used, without putting it in. The effect of putting oil in is, in a great many cases, to cause the crown sheet to come down, or the lower sheets to bag. When first put in the oil floats, but it gradually picks up scum from the sur- face, in which scum there is always more or less actual mud thrown up from the bottom by the boiling water; the oil then becomes like tar, and being heavy settles on the plates and sticks fast. Since the water cannot get under- neath it the plates are overheated and come down, notwithstanding the fact that there is plenty of water in the boiler. Keep every kind of grease out of a steam boiler, if you have to filter the feed water to do it. BRACES AND STAYS. We have now a clean boiler to deal with ; let us see in what condition it is as regards IO strength. The braces are the first to be con- sidered. Perhaps some of them are carried away entirely; such a state of things is by no means unknown. They must be replaced at once by boiler makers, who should also go over every other pan of the boiler and test it for condition > but if there are no boiler makers handy the engineer must do it himself. The boiler most generally used is the return tubular, which is a plain cylinder with an ex- ternal fire-box, from which the heat traverses the bottom and enters the tubes at the back, passing through them to the breeching and smoke-stack in front. The weak point in the return tubular boiler is directly over the bridge- wall, where the heat deflected from the wall strikes upon the shell. This spot needs to be carefully examined, for unless the boiler has been well taken care of it wll be found weak and unsafe. If any doubt exists, a half inch hole should be drilled in the bottom to ascer- tain the exact thickness of the plate, when, if thinner than the shell elsewhere, it should be removed, and a new plate put in. The sides of the boiler should also be examined near the wall, or where the boiler meets the brick- work, for here there is often trouble from corrosion ; also at the junction of the blow-pipe in the bottom or at the end of the boiler. II CHAPTER III. MUD DRUMS AND FEED-PIPE. If there is a mud-drum attached to the boil- er examine it very thoroughly, for explosions of mud-drums are very common. If the mud- drum is buried, as it often is, it is probably corroded greatly. The proper place for a mud-drum is outside of the boiler, in plain sight, where it can be got at and cleaned out weekly. The object of it is to catch all the free mud, so to call it, which is thrown down at night when the boiler is not running. With some water used for steam making, as on Western rivers, the quantity of mud so de- posited is very large, and if not removed it will be driven back into the boiler. This is particularly true where the feed pipe enters through one end of the mud-drum. It does not require much thought to see that this wholly defeats the object of the mud-drum, for the sediment which collects over night is forced through the boiler again at the first stroke of the pump in the morning. As to the best place for the feedpipe to enter the boiler there is a difference of opinion among engineers, but there is no doubt but that the worst place is through the mud-drum, for the reason given. Some think that the feed should 12 enter the coolest part; some put it in the steam space, and some enter it at the front end alongside the fire. An objection to this is the bad effect of water cooler than the water in the boiler upon hot plates; an advantage is the propulsion of any sediment that may lie upon the bottom of the boiler lo the back end of it, where there is no trouble in removing it; another benefit is that the mechanical action of the entering jet assists the circulation by forcibly driving the heated water from the front to the back, and replacing it with cooler water, but to effect these objects the feed pipe must project within the boiler for a few inches so as to give what we shall call a straight shot from it. BOILER FITTINGS. In these are included every sort of attach- ment to a boiler, the water gauge, gauge cocks, safety valve, checks of all kinds, and the blow- off valve or cock for blowing the water out of the boiler. This last is a much more important detail than it is generally supposed to be, and many accidents nave happened from careless- ness with it. These accidents occurred from " sticking " any sort of a bent pipe (we have actually seen an old leader pipe from a house used) over the end of the nipple or elbow on the blow-pipe. The blow-pipe connection should be made as firmly and as securely as any other attachment to a boiler. If one re- flects for a moment, it is easy to see that there is a tremendous strain on a pipe which is dis- charging a two inch stream of water under 60 or 70 pounds pressure. A boiler never should be blown off at this pressure, but it sometimes has to be, and preparation should be made for it. No elbows should be used where it is pos- sible to avoid them ; the pipe should run as straight as it can from the boiler to the outer air, and if a cock is used care should be taken that it is always in perfect order. It should not leak a drop ; the bolt at bottom which keeps the plug in the cock should be accurately fitted, of full length, entering the plug not less than i% inches, and have a good head on it. It must never be meddled with or touched, except to open or close it, w T hen under pressure. Don't hit it with a hammer, either on the under side to start the plug up if it sticks, or on the top for any purpose. Remember that it is under pressure, and if it gives way it is almost certain death to any one near it. Defer all tin- kering and investigation until the boiler is cold; or, in other words, make everything secure be- fore steam is on; then there will be no trouble. Forethought, care, and caution, are absolutely indispensable qualifications in an engineer, and 14 it is useless to expect success or ordinary economy without them. No man can be an engineer worthy of the name who is careless or has not his wits about him at all times. Mr. I-Didn't-Think has no business with a steam boiler. What has been said of the blow-cock is true of all the other fittings. Every one of them must be in perfect order to be safe and efficient; an engineer must bear in mind that he is deal- ing with a tremendous agent, which is safe only when in its place and under control, and every gauge or fitting of every kind must be securely in place and tight of itself, that is, tight without makeshifts of any kind. The safety valve in particular must be tight, for a great deal of coal can be lost by a leaky valve. It should be free and clear in the hoist, or where the lever is to be raised if it is of the lever type and entirely free from rust in all parts. A safety valve is for use, not for emer- gency, and if it is not in order it will not act when the emergency comes, if it ever does. It is not every engineer that can do the work which we have mentioned with his own hands, for not all persons in charge of engines are machinists; these instructions convey a knowl- edge of what is needed, and the work can be supplied by those competent to perform it. CHAPTER IV. GRATE BARS AND TUBES. One of the most important parts of a boiler is the grate. Curiously enough but fe\v give this matter sufficient thought, but it is plain upon reflection that the air \vhich is needed to support combustion must be supplied through it. If the bars are warped and broken, too much air goes through them, with the effect of wasting fuel or checking the free s'.eaming of the boiler. Moreover, a broken grate bar pre- vents proper firing, or attention to the fire ; all the bars should be in good order, 'with no open spaces at the ends (front or back) or sides. As this bears directly upon the subject of combus- tion, it will be more explicitly alluded to fur- ther along in this work. The tubes or flues particularly demand at- tention, and must be absolutely clean inside and out. In a former article we have given directions how to clean them outside that is, on the water side, but they must be clean on the fire side too. With anthracite coal this is not a matter of difficulty, but with soft coal it is ; not so much through the soot which accu- mulates in them as with the " gurry," for want of a better name, which is burned on. This last is the tarry distillates of the coal, or heavier i6 products of combustion, which are condensed on the inside of the tubes when the boiler is comparatively cold, or in getting up steam every morning, and is by no means easy to remove. It not only checks steam making by obstructing the heat from passing through the tubes, but it hinders the draught by the ad- herence of soot and roughening the surface of the tubes. It would seem that the fire should burn this deposit off, but it requires a much higher temperature to do this than that in the tubes, and the only way to remove it when it has accumulated in quantity is to thoroughly slush the tubes with crude petroleum oil, ap- plied with a swab and allowed to remain for a day or so, when it should be swabbed out again. This is a job which but few persons care to undertake, particularly if the boiler is large, but in some cases it becomes neccessary. Crude petroleum is a solvent for tar, and will clean the tubes thoroughly. Of course it has to be undertaken in holiday time, when the boiler is idle for a day or two, for to be of any service the oil must remain in the tubes at least 24 hours. It is of no use to try to rasp this " gurry" out with steel brushes- or scrapers. It is as tough as India-rubber and a scraper slides over it. BRIDGE WALLS. The bridge wall in a boiler is intended to delay the products of combustion in the fire- box as long as possible, and to confine the heat from the fire within the area of the grate. To do this it is manifest that the throat, or opening over the bridge wall, between the top of it and the boiler, should be as small as it can be, and leave room enough for a good "draught," so-called. There is, however, a danger in this, and this danger is that if the throat is too narrow, the heat, and sometimes the flame, is sharply deflected and concentrated directly upon one spot over the wall. The result of this is that the sheet for a foot or so is fire-eaten, or thinned and weakened ; it is burned, as boiler makers would say, notwith- standing there may have been plenty of water in the boiler. The opening over the bridge wall should never exceed ten inches, nor be less than eight inches, and it should follow the curve of the boiler. There are a great many patents on bridge walls which are in- tended to improve the combustion by admit- ting air over them, or through them, but never having had any experience with them we can- not say anything about them. Assuming that the boiler has been put in good condition, we will look at the engine. i8 The hints given in the previous chapters should enable any intelligent man who is fit to be about a steam plant, to have a boiler which will steam freely and as economically as its construction will allow. A treatise could be written upon boilers alone, and many such works are in existence. The contents, however, relate more particularly to the con- struction, a matter which does not enter into an engineers duties. THE SLIDE-VALVE THROTTLING ENGINE. The commonest form of steam engine in use to-day is the slide-valve throttling engine, which is regulated by governors of various kinds. It is the simplest of machines, easily managed by any one after a little instruction, and frequently is found in charge of men and boys who have had no experience whatever, they merely knowing that a certain valve has to be opened, and that the engine must be at half-stroke to start. Such persons are not en- gineers in any sense of the word, for they do not intend to follow the business any longer than they can help. Our instructions are not directed to them, but to intelligent young men who have started with the intention of learning all that they can. The first thing to do then in taking charge of an engine is to see in what condition it has been handed over, in order that 19 you may not be blamed for the sins of those who preceded you. The cylinder is the seat of power, and we want to examine it as soon as we can get a chance. If we have been under steam the day before, we leave the engine on the back center at night (Saturday night foi instance), and take off the cylinder head. The piston is then at the end of its stroke, and we have an opportunity to see what the clearance is between the piston and the cylinder head. The latter detail will leave its mark on the cylinder after it is taken out, so it will be easy to measure directly from the piston to the said mark. Some clearance is necssary for safe working, but it should be just as little as pos- sible; clearance is waste room that has to be filled with live steam at every stroke before any work is done on the piston. As a rule excessive clearance is given in small engines, for no reason whatever, except that some builders appear to think that there is less danger of breaking down. Suppose that the cylinder is 12 inches diameter: then the p ; ston should run within one-quarter of an inch of the head. If the piston is of that class where the follower bolts stick out the depths of their heads, it cannot run so close as this, and probably there is an inch or more clearance in such a cylinder, but it is easy to reduce the 20 clearance in such cases to the lowest point, and this is easily done by taking- the follower to a machine shop and having the bolt holes counterbored, so as to let the heads in as far as possible; having done this, fill up on the head itself by bolting on a cast-iron plate of the re- quired thickness, cutting out where it covers the steam port. The reduction of clearance often makes a boiler much larger; or, in plainer terms, since less waste occurs it is easier to keep steam on a boiler than when the clear- ance is excessive. Having found what the clearance is on the back end then, we discon- nect the piston from the cross-head, and (run- ning the crank on the forward center), we find what it is on the front end. This we do by shoving the piston clear up against the for- ward head. Having done this we measure from the follower back to the end of the stroke, as shown by the wear on the guides, and the wear on the cylinder itself. If this measure- ment is half an inch longer than the working stroke of the piston, there is half an inch clearance on the front end, and as there are no follower bolts on that end it is all waste, ex- cept so much as is actually needed for the safe wording of the engine. We should, if the en- gine was ours, reduce this clearance also, to the same degree that we did the back end, but 21 as it entails more or less work for the shop, it will be as well to leave the clearance half an inch on the front end; if the clearance is one inch, however, no consideration of trouble or expense should be spared to reduce it in the same way that we fixed the back head, by adding- to the head itself. The clearance in any engine must be reduced to its lowest terms, for by doing this, if the engine is yours, you put money in your pocket; if it belongs to some one else and you are in charge of it, you get the credit of making a saving, and this will be a feather in ycur cap worth working for. 22 CHAPTER V. THE PISTON. Now that we have the clearance matter at- tended to, let us see what kind of a looking thing 1 we have for a piston. This detail of a steam engine is of all conceivable forms and some inconceivable forms, to any one who thinks what a piston has to do. They are made as heavy as hydraulic plungers, and with as many attachments as possible, in the shape of rings, with springs to keep the rings out to the cylinder, and screws in the springs to keep the springs out to the rings. The reason that some firms make them in this way is because their grandfathers made them so, and that is reason enough in their eyes. If the piston you have taken out is of this class it is your and the owner's misfortune, but as we are not giving instructions upon how to build engines, we will merely state how this old-fashioned piston is to be put in as good condition as pos- sible. Pistons are liable to become leaky in the following places : between their flanges where the rings bear; between the rings and the cylinder itself; through the follower into the body of the piston. Wherever there is a joint look for a leak, for joints become imper- fect through use and time. If the rings move 23 back and forth between the nanges of the piston they leak, and must be made tight by skinning off the follower. This is of course a shop job, with which the engineer has nothing to do, but before the piston is sent to the shop for repairs the engineer should be sure that the piston needs it. Very often it will be found by examination that dirt or " burrs " have got in betw r een the follower and the spider, or else the thread on the bolt-holes in the spider has been raised around the edges, so that the fol^ lower will not go down, iron and iron. An experienced engineer will soon find out whether these things have happened by taking a smooth file and going carefully over the fol- lower-seat on the spider, or main casting of the piston. In this way he will find all the burrs or bruises that have raised the surface, and dress them off level ; then when he puts the follower on again and screws it up solid without the rings in, he should take a hammer and strike on the outside of the follower opposite solid iron. If the follower is tight on its seat it will sound like striking on an anvil ; if it is leaky the sound given out will be like striking a piece of iron lying on an anvil. Leaks can also be told by the appearance of the parts, but as this is not easily conveyed in print we shall not attempt it. The best way 24 in all cases is to send the piston to a good machine shop and have it put in perfect order, and this is why it was taken out the first thing-, so that it might be going forward while we are dismantling other parts of the engine. THE SLIDE VALVE. The next thing we do to ascertain the condi- tion of our engine is to take the bonnet off the steam chest and see in what shape the valve and its seat are. An inexperienced man is very likely to get into trouble here, and do damage to the engine. Bolts and nuts which have been long undisturbed are very hard to start, and in very many cases they either break short off in the casting, or else, in the case of stud bolts, come away at the bottom, and unscrew from the casting. Either of these misfortunes is bad, because it is not an easy task to get out a broken stud bolt, or to make one tight in its seat after it has been forcibly removed ; there- fore, if the nuts do not yield to moderate force exerted on a wrench, pour a little kerosene on them and let them stand half an hour. Kero- sene is the most pervasive fluid known to the trade, and it will seep into the most minute crevices; if after its application the nuts will not then start, get an iron ring, or a big nut with some body of metal in it and heat it red hot. Put this over the stubborn nut until it has 25 become very warm and it will come away without any trouble. If we digress here for a moment it is because the occasion seems to demand it. This digres- sion is to again insist upon the necessity of care and caution in dealing with a steam en- gine. It is no evidence of skill for a man to go at a steam engine with a hammer and wrench and slaughter right and left, for by pur- suing this course he can do more damage in a moment than he can repair in a day, and he can save both time and money by going at every job in a workmanlike manner. The slide valve is really the heart of the steam engine, for upon its perfect condition and perfect action everything depends ; if it is off its seat or badly set there can be no econ- omy. When we take up a slide valve in an old engine we shall, in nine cases out of ten, find it in very bad condition. This is owing, in a great measure, to the way in which it is connected to the mechanism that operates it, and to the way in which it is constructed. Most slide valves are extremely faulty in this respect. In order to keep the steam chest as short as possible, the valve seat is made short, and very often the valve overruns the seat, so as not to wear a shoulder on it. The valve stem, acting on the stuffing-box as a fulcrum, 26 tends to pry the valve off its seat, notwith- standing the pressure upon it, with the result that the face of the valve is worn rounding in the direction of its stroke. Where this is the case it must necessarily leak, for a slide valve seat is like the slide valve itself if one is rounding the other must be hollow, in some de- gree, unless it is very much harder than the valve itself. The time to test a valve for leaks is when the engine is running, and it can be told very quickly by watching the exhaust where it can be seen. If this is sharp and clear at every stroke the valve is tight, but if it is followed by a secondary jet that scarcely clears the exhaust pipe, the valve or the pis- ton leaks, and quite likely both ; any leak through the piston would also show on the ex- haust, but in this case, unless the piston leaks very badly indeed, it is likely to be a leak of the valve which shows on the exhaust. To test it for condition, obtain a straight edge and lay it across. Hold the straight edge absolute- ly vertical, not tipped to one side, and it will soon show in what condition the valve and the seat are. The remedy for a leaky slide valve is in the machine shop. 2 7 CHAPTER VI. TESTING THE VALVE WITH RELATION TO THE PORTS. To find out whether the valve is properly made in the first instance, or whether it has been tampered with by some engineer in charge before you, proceed as follows : Take a sheet of paper large enough to entirely cover the valve seat and lay it on it. Rub all over the edges of the ports so as to obtain a fac Fig. i. simile of them. Then get a piece of pine half an inch thick and three inches wide, and put the edge of it on the diagram, transferring the ports to the stick, thus : Do the same to the valve, and you will have a fac simile of the valve and its ports, which can be more readily handled than by taking the valve itself, which is heavy and hard to see distinctly when in the chest. Now these directions sound very simple, and are very easy to understand by 28 one who knows all about the matter before- hand, and who knows what he expects to see, but they are not so simple to a young- man who reads them for the first time, or who is unacquainted with the action of a slide valve, and it is mainly to readers of this class that this work is addressed. But we will try to make it as simple as possible, and so that any- one without previous knowledge of a slide valve can see at a glance whether it is properly Fig. 2. made or not Actual comparison of the valve and valve seat templets will appear further on. Let us say, however, that there are slide valves of many kinds, flat faced, round faced (as in the case of a piston slide-valve), V faced, etc.; but in this article, when we say slide valve we refer especially to the common cast- iron box without a bottom, which is generally used in engines, as shown in the engraving, fig. 2. This covers both ports and extends some distance over them on each side. That 2 9 is to say, the end of the valve laps over the ports, and the part projecting is called the lap of the valve. The cavity inside the valve is the exhaust port of the valve, and this also laps over the exhaust edge of the steam port some- times ; the outside lap is called steam lap, or lap on the steam side, and the inside lap is called exhaust lap when there is any. Usually the exhaust port in the valve coincides with the inside edges of the steam ports as shown in Steam lap Exhaust port of value / line and line exhaust "\ Exhaust port mjjf of value face Fig. 3. fig. 3, and when in this condition it is said to have line and line exhaust. Sometimes the exhaust is given clearance ; that is to say, the steam port on the exhaust side is open slightly, and when in this condition it is said to have exhaust lead, or lead on the exhaust side. A slide valve then, works normally, that is to say naturally, under these conditions : It is a cast-iron box covering both ports all round, so that no steam can get into the cylinder unless 30 the valve is moved so as to expose one of the ports. To recapitulate : the part which projects over the ports is called steam lap ; the inside cavity of the valve is the exhaust port ; the inside edge of the steam port is the exhaust side ; the outside end of the valve is the steam side; and the same on both sides of course. These details are, naturally, familiar enough to experienced engineers, but we must not forget that there are young men coming into the trade continually who have all their trade before them, and who have it to learn as we had to, and it is for them that these explanations are given. Let us now look at the action of the valve. DEFECTS OF THE SLIDE VALVE. Were it not for one inherent, and we may say, hereditary defect, the slide valve would be the ideal one for its purpose, for all the functions are performed by one valve. This defect is that it is limited in its application to working steam expansively. As will be readily seen by anyone who uses the templet, fig. i, where the valve face is shown in section, when it is applied to the valve and moved to the various positions of opening and closing the valve, the exhaust is more or less throttled or choked; its area is greatly reduced, so that escape of the exhaust is delayed. The result of this is that the exhaust steam presses back on the piston (back pressure so-called), and takes away just so much from the power of the live steam on the other side which is driving the piston for- ward. This back pressure varies in amount with the position of the valve and the point of the piston stroke at which the valve closes. For instance, in plain words, when a slide valve cuts off at three-quarters of the piston stroke there should be little or no back pressure in a properly constructed valve, for the exhaust is open long enough to allow all the dead steam to escape, but at points of the piston stroke under three-quarters the exhaust is not free, and a cut-off obtained with a common slide valve under five-eighths of the piston stroke has to be paid for by loss of live steam pressure. Notwithstanding this fact there are many slide valves cutting off to-day at one-half of the stroke, and under that at times, and the de- signers of them are satisfied that is to say, they have to be satisfied for the common slide valve will always create undue back pressure at points under eleven-sixteenths of the piston stroke. This is shown very plainly by indi- cator cards, where the last part of the exhaust is caught in the cylinder by the piston and pushed uphill, if we may so express it, until (when nearly on the center) there is a pressure 3 2 opposed to the piston closely approximating boiler pressure. Whether this is economy or not every one must judge for themselves. To expend live steam pressure and power stored in the flywheel in trying to make dead steam alive, by squeezing it between the piston and cylinder head, always seemed to us unwise, for the reason that we do not get back as much work from the imprisoned steam as we spent to catch it, but as it is no part of our intention to discuss moot points or theories in this sedes, we go no further in this direction. 33 CHAPTER VII. LAP AND LEAD. The object of putting- lap on a slide valve is to cut off the steam early in the stroke of the piston. Suppose the steam end of the valve had no lap at all, but barely covered the steam port: then so soon as the piston moved the valve would open and continue opening, clos- ing barely in time to open again for the return stroke of the piston. Now suppose we add one-quarter of an inch lap to the valve ; then the valve would open just as soon as it did be- fore, because we have advanced the eccentric to permit it to open, but it would close sooner by the amount of the lap, because we have stolen, so to speak, a quarter of an inch from the travel of the valve by advancing the eccen- tric ; therefore, if it closes sooner it cuts off the live steam earlier in the stroke; but, as ex- plained previously, it cuts off the exhaust also. We introduce this as an illustration of the uses of lap. Laps on slide valves vary all the way from half an inch upon a twenty-five horse-power engine to one inch and upward on high power engines ; on very large marine engines the lap amounts to 3" sometimes ; on locomotives it is usually one inch. If you have aii engine which "takes steam all the 3 34 way," that is, works full stroke, you can materially increase its economy, and to some extent its power, by adding lap to the valve upon the steam side ; the amount of it cannot be stated definitely, but must be governed by the size of the engine. Lead on a slide valve is the amount that the port is open to admit steam when the engine is on the dead center. The object of lead is two-fold: to have the ports and cylinder full of live steam the instant that the return stroke begins, and to check the momentum of the parts as they turn the center, or change the direction of motion. Now both the lap and the lead of a valve have an intimate relation to setting the valve for the distribution of steam, and as this will be alluded to further on in this series, we will say no more under these heads, because we shall be obliged to traverse the same ground, and this involves tiresome repetitions. THE PRESSURE ON A SLIDE VALVE. Another defect or objection to a slide valve is the pressure upon it and the power required to drive it. This is great, though it is not so large as it is generally supposed to be. Spe- cifically, in the case of small steam engines, Mr. C. Giddings, of Massillon, Ohio, made a dynamometer for the purpose of ascertaining the power required to move the valve on a 35 6^4" X IQ" horizontal engine. The surfaces were not given nor the pressures, but when exerting 13.5 horse-power at 200 revs, per minute, the power expended in working the valve was one-fifth of one horse-power. In an engine of 9" cyl. X 12" stroke, with a three- ported flat slide valve, at 100 revs, of engine per minute, the power required to drive the valve was 7.3 per cent, of the power developed by the engine, which last was n. i h. p. With a balanced slide valve on the same engine, at 100 revs., developing 15.6 h. p., the percentage of load on the valve stem was only i per cent, {Mechanical Engineer, page 62, vol 12, 1886). This adduces an argument in favor of balanced valves vs. plain valves ; that is to say, the one is 6. i per cent, lighter than the other to drive, but the fact remains that without any balanc- ing but 7 per cent, of the power of the engine was required to drive it in a small engine. We do not say that this is not serious, nor do we think it unworthy of notice, but the fact re- mains that some valves require less pressure to work than others, owing to the manner in which they are lubricated and the condition of the seats. This last is the point we wish to make, for if the seat is cut the power required will be much greater than if it was in good order. Moreover, if the metal of the valve and 36 seat are of the same degree of hardness, the valve will not work so well as when one is harder than the other. Of course the valve should be the softest, for it is easy to replace or re-face, while the seat is difficult to get at. The pressure on top of a slide valve is the steam in the chest bearing it down. When the en- gine is at work there is a pressure beneath the valve, reacting on the under side of its face, for the area of the port and through it. There is also a back pressure from the exhaust steam passing through the exhaust port of the valve ; both of these pressures tend to reduce the direct pressure on the back of the valve, but to what extent can only be told by recording the facts in some particular case. The mean effec- tive pressure shown by cards, as existing in the cylinder, is the pressure acting on the port- area face of the slide valve. STEM CONNECTIONS TO THE VALVE. We have said previously that one defect of the slide valve was its liability to wear untrue. One great cause of this is the manner in which the stem is connected to the valve itself. In locomotives the yoke is used exclusively. We believe there is not a single modern locomo- tive built without it, the reason being that there are no nuts or other details to work loose in- side the chest. 37 This is of the greatest importance in an en- gine which is worked hard under high press-ure constantly, but the yoke has its defects as well as all other mechanical devices. It frequently breaks, and at times cramps the valve so that it does not seat squarely ; it cannot be got out Fig. 4. without lifting the steam chest, and it is also very heavy, and unless supported by the valve itself, wears away the gland very rapidly. Other common connections to valves are the nut in a pocket on the back, four nuts on a straight stem, the latter being run through a hole in the back of the valve, as shown in fig. 5 ; T heads on the stem are also common, the T fitting in a cross in the back of the valve. The nut in a pocket connection is one which is very liable to give trouble to engineers, for it is easy to see, unless the nut is exactly at right angles to the travel of the valve, that it is apt to cramp the valve and keep it off i s seat. As the stem is constantly wearing down the trouble is of frequent occurrence, and it is diffi- cult to detect when the engine is cold, for the reason that the valve appears to be solid on its Nut Figs. 5 and 6. seat. We have seen engines which refused work simply from this connection to the valve. Upon opening the throttle the engine would get steam under the valve and through both ports, and nothing but easing the nut in the pocket would let the valve down solid. Fig. 5 is the 39 nut and pocket connection, and the nut should in all cases be faced rounding on the working faces. A far better and simpler modification of this plan, and one we have used with suc- cess, is shown in fig. 6; it never fouls, and the nut allows the valve system to be lengthened or shortened without the use of jam nuts. It is easily put in or taken out, and fills all the re- quirements. The solid nut arrangement shown is, to our way of thinking, the best. It holds firmly if properly fitted up, and it is also cheap to make, being all lathe work. It never cocks the valve or binds it any way ; take it all in all, it is hard to find one better. These connections are the ones that are most commonly met with, and it is well to know what to expect of them. 40 CHAPTER VIII. VALVES OFF THEIR SEATS. Now suppose we start or try to start our en- gine for the first time, and on opening the throttle find that the engine will not move, or will move as well one way as the other and without power in any direction. We know that steam is in the chest by the heat of it, and if everything was all right the engine should do its work; since it does not, there is plainly something wrong with the slide valve, and in nine cases out of ten it is off its seat. If it was simply wrongly set, the piston would go one way but not the other ; it would make a great plunge forward or backward and stop there, but it would not drive the crank over the cen- ter. A slide valve does not require much to lift it from its seat, and it may occur at any time ; a scale blown in from the steam pipe may get under one end and lift it enough to float the valve, then the steam will blow through the exhaust. When this is observed blowing through the remedy to be adopted is, in the small engines, to rap the valve stem smartly with a billet of wood, when, if the connection is in fault, it will frequently release the valve and allow it to seat itself. If something has 41 got under the edge of the valve, move the stem as rapidly as possible back and forth, and it will work the obstruction off. If all these fail the only remedy is to open the chest and get at the valve itself. If water gets into the cylin- der in any quantity it is very apt to jam the valve stem connection by bearing up on the under side of the valve through the steam port; it may even bend the stem in small engines. If this happens do not undertake any hammer and tongs remedies, but disconnect the stem, heat it black hot and straighten it with a mallet on a block of wood. Cold iron or steel breaks easily. VALVE STEM GUIDES. In most modern slide valve engines the steam chest is on the side right or left as oc- casion demands (usually the right), and the stem is directly connected to the eccentric rod without the intervention of a rock-shaft. The end of the stem is flattened, or squared, and is carried in a guide which may or may not be of service; if it is in line with the direct travel of the valve it is, but experience teaches that these apparently harmless guides can make a great deal of trouble for inexperienced persons, who fancy that the stem must move tightly in them. This is not so; the outer end of the valve stem must not be tied up in any way, 42 but must be at perfect liberty, in order to allow the valve to lie flat on its seat. ' The only use of a guide on a valve stem is to prevent the weight of the eccentric rod from springing it downward, and to carry the weight of the valve stem itself; beyond this the valve re- quires no guiding, for the stem will attend to that. Do not, then, screw up the guide on the valve stem so tightly as to bind it in any way; it should work freely with a slight play in all directions. GOVERNORS. Let us leave the valve and all its connec- tions, including the eccentric, until we get further in our investigations, and look at the governor or throttle valve. In early days en- gine builders made their own governors; these were always the common two-ball governors which regulated the engine (or pretended to) by means of a butterfly valve, so-called, in the steam pipe. This valve was merely a flat piece of brass with a shaft through it, hung in the steam pipe just as a damper is hung- in a stove pipe, and usually one of these devices fitted about as well as the other. That is to say, the throttle was so badly fitted that it did not answer its purpose at all, and, added to this, its position in the steam pipe was such that it defeated its own object The valve was so far 43 from the steam chest that there was always a supply of steam between it and the main slide valve sufficient to run the engine at full power; consequently, when the load on the engine was reduced and the engine ran faster, the speed was not checked until the supply ran out, even though the governor had partly closed the throttle; then when the supply was worked off the engine slowed down, only to repeat the irregular motion at every change of load. Moreover, the old-fashioned two-ball governor was sluggish in its motions. The balls had to move through considerable arcs before the throttle acted at all; it had too many joints, which bound themselves tight by their motion, and it was so defective that it was cast aside for better devices. There are a good many descendants of the same family, however, still in the market, and they have the same inherent defects. The butterfly valve has wholly disappeared; at the present time no one makes them. Neither do engine builders make their own governors. Many patented governors for steam engines are manufactured by parties who make a specialty of them, and these makers use a simple cylindrical shell moving in n cylinder as a throttle valve. This works easily and tightly, and is a vast im- provement on the old gear. Its faults are 44 chiefly those of adjustment, and arise from neglect or carelessness on the part of those who run the engine. The parts are apt to wear, or else the stem gets lengthened by un- screwing, so that the valve drops from its natural osition and blinds the ports. In caring for and repairing a governor all that is necessary is to see that the joints, when there are any (in some there are none, as in the Pickering), are free, the pins perfectly round and true, and free from burnt oil or gum; that the stem is straight, works freely and has no shoulders on it from working in one place constantly, and that the valve is in its proper place when the governor is geared up. RUNNING WITH THE SUN. There are a great many persons in existence yet who put faith in traditions, and who will gravely assure one that such or such a ma- chine does not work properly because it does not "run with the sun." This is a notion that is firmly believed in by many who have faith, but no reasoning power. The sun has no influence upon, or any connection with machines made by man, with the sole excep- tion of sun dials, and any machine which is in order will just run as well "against the sun" as "with the sun." Therefore, let no person impose upon you by telling you that the rea^ 45 son a bewitched governor does not work is be- cause it runs against the sun. Suppose the engine stands east and west, how can it run against or with the sun ? We used the ex- pression "bewitched governor" in a figura- tive sense only, but let no engineer ever give up the search for a cause of bad working in a de- tail. It may be hidden, but it can be found by searching. There is always a cause for ir- regular action in all machines. CHAPTER IX. ECCENTRICS AND CONNECTIONS. The office performed by an eccentric is to move the valve to admit steam at alternate ends of the cylinder. The eccentric is simply a wheel hung- out of its own center. Its own center is a point equi-distant from the circum- ference. If hung on a shaft in this way it would have no other motion than a true rotary or concentric motion around the shaft, the same as a flywheel has on its shaft. Being hung out of its center, it has an untrue motion an eccentric one from which it takes its name. This explanation may sound somewhat puerile to experts, but there is an idea in the minds of many that an eccentric has some mysterious action which makes it especially fit for driving steam valves. We have been told by some that the eccentric ran fast and slow without reference to the speed of rotation of the engine, and it had, for that reason, a "dwell," so to call it, at each end of the stroke, that permitted the steam to enter quickly and to escape freely. The ''dwell" exists, but it is is not by reason of any peculiarity of the eccentric itself, but on account of changing the motion of the valve from forward to back. At 47 this period in the stroke the eccentric and all its connections are in line, see fig. 7, and for a portion of the stroke, from a to 6, the eccentric exerts little or no effect upon its rod and the connections to it ; in itself, however, it is mov- ing- at the same speed it always moves at, Fig. 7. which speed is that of the engine. The idea that an eccentric has a variable speed doubt- less arose from some one looking at the long side of it passing over the shaft rapidly, and comparing it with the short side, which does move slower than the long side, because it is nearer the center of the shaft. Now, an ec- centric is hung out of its own center just half the stroke of the valve, because in a complete revolution it will double this throw, as it is called. The throw of an eccentric, then, is the amount it is out of truth (fig. 7), or the distance 48 from the center of the shaft to the center of the eccentric. Suppose this to be i}^ inches, then the eccentric is said to have i*4 inches throw, and the travel of the valve is three inches. Connections from the valve stem to the ec- centric are of various kinds. Where the steam chest is on the side the eccentric rod is con- nected directly to the valve stem by a pin on the side of the stem, or by a spade handle, as it is called, worked on the stem itself. Some- times, however, as when the steam chest is not on the side, there is a rock shaft between the eccentric and valve stem. This makes no difference in the action of the eccentric, but makes some difference in the position of it on the shaft, as will appear later on in this series. Sometimes there is an idler shaft, which also rocks, but makes no difference in the position of the eccentric on the shaft from that which it occupies when directly connected. The con- nections are in all cases merely carriers or dis- tributers of motion between the eccentric and the valve itself, and need not be considered as affecting the motion, except as hereafter ap- pears. THE CRANK PIN. There is no more important adjunct of an engine than the crank pin, for through it all the 49 power of the steam is transmitted. This state- ment does not refer to its office wholly, but to its condition and its construction. In most cases engineers are powerless to alter this with- out going- to a great deal of expense, but they can at all times keep it in good order, and in such condition that the friction of it is reduced as much as possible. Engineers worthy of the name take the greatest pride in having this de- tail free from every scratch or flaw on its working face, and, above all, never allow it to get more than hand-warm ; that is, about the heat of the human hand. It should not heat at all if properly attended to and when properly proportioned in the first instance, but there are many proprietors who run engines much be- yond the power they were intended for, and when this is the case the crank pin is liable to suffer first. Crank pins heat from several causes. When they have always run cool with the normal load on the engine, and de- velop a tendency to heat when the load is in- creased, the cause is too much pressure per square inch of surface ; this forces out the oil and brings the boxes into forcible contact with the pin, so that heat is engendered. A remedy in cases like this is to use a heavy oil, or a grease composed of equal parts of plumbago and tallow or lard. This finds its way into 4 50 the most minute ridges or imperfections in the bearing-, and keeps the surfaces apart ; it is a very excellent lubricant to use upon an over- loaded engine. More generally, however, crank pins heat from constant tinkering with the connecting rod end. An engineer hears a pound, and arguing at once that the crank pin brass must he slack, drives the key down, with the result of heating the pin. Now this matter of adjusting brasses on crank pins and on other bearings is an important one, not so well un- derstood as it should be. In a great many cases the brasses are not properly fitted when they leave the shop, and are liable to cause trouble from that fact. High speed engines of the best class are properly made, for the build- ers of them are men of experience, but there are some persons who, as soon as they get charge of such engines, proceed to "relieve" the brasses in the wrong place, so that they can key them up. Now what is good for a high speed engine is good for a slow speed engine, and every bearing, no matter what its office, should bear " brass and brass," as the term is, and shown in the diagram at a not as shown at b. The brasses should butt solidly and fairly together, and the pin should work easily inside of them. Then it will have merely the friction of work, and not the friction due to the work, 5 1 with that due to the pressure of the key added. Many persons hold that no more pressure can be put upon a crank pin than that due to the work, and unless the pressure of the key or bolts exceeds that of the work, it adds nothing to the labor of the bearing. Those who hold this view are requested to try the experiment of driving in the key a little on a bearing which shows signs of heating. They will speedily Fig. relinquish their theory. Another cause of heat- ing of crank pins and other bearings is faulty workmanship. The brasses do not bear fairly or seat squarely and while they appear all right to the eye they are not all right to the bearing, which speedily gets warm over the matter. A crank pin brass must seat squarely on the end of the connecting rod, and the rod end itself must be square. If the key, when driven, 52 forces the brass to one side or the other, and twists the strap on the rod so that its sharp edges can be felt on the side, it will draw the brass a-cock-bill on the pin, and make it bear the hardest on one side of it, reducing the area for working by the amount it is out of truth. The same condition of things is true of the main bearing. If the brasses do not bed fairly on the bottom of the pillow block casting, and do not go down evenly, without springing in any way, they will not run as they should. It matters not whether an engineer is a workman or not, in regard to his seeing these things. When they are pointed out to him, he can, and that is our reason for directing attention to them. If he knows where the fault is he can find men to remedy it. Another cause of heating in bearings is too much surface in contact that is merely friction- al. This is best explained by fig. 9, where all the work of transferring the power of the steam is done upon the surface of the pin, which is shown in section. All the bearing beyond this is of no service, but is a positive injury if if touches the pin, for it merely rubs and wears, without doing any good. Engineers then " clear " the brass on its sides as shown in fig. 9, for all bearings, whether those of the main shaft or elsewhere. We say "clear" the brass 53 which means that it is to be just free, or so that it does not touch; not as shown in the diagram, where it has to be exaggerated to be seen at all. This clearance has another value, that of permitting the oil to stay on the pin, and to cover it at all times. This end is also furthered by cutting X grooves in the brasses, but this practice we have never been greatly in favor of, except in solid brasses which oscillate, or Fig. 9. do not completely traverse the pin. For these last oil grooves are essential, inasmuch as when they are hard worked the oil is not dis- tributed as it is in a complete revolution, and they are very liable to cut from want of access of the oil to all parts. Oil grooves, however, have the disadvantage of retaining dirt which may find its way in, they invite fracture, and they reduce the bearing surface. They are not to be used indiscriminately. No greater annoyance can happen to an en- 54 gineerthan to have bearings heat beyond a cer- tain degree. When shafts run hand warm it is no great matter, but it is better to have them quite cold, for then they do not give any anxi- ety lest they should become hot. Heat of any degree about a bearing is certain evidence of friction; what causes it is for an engineer to find out. If all bearings about an engine were ab- solutely parallel to each other, perfectly round, smooth, and true, of ample area and properly lubricated, they certainly would not give any trouble, but it is because some of the qualities above mentioned are lacking that they do give trouble. Want of proper materials in contact is also a cause of heating; dirty lubricating oil, or that which is too light in body for the work to be done, will also work badly for an en- gineer. Badly designed engine frames cause heating of main bearings by springing; settling- of foundations, and badly fitted bearings do the same. For example, if on taking up a bearing that heats, the brass is found to bear as shown by the shaded lines in figure 10, the remedy is to scrape away the shaded portions so as to have a fair bearing, but before doing this an engineer should be sure that the fault is in the brass and not in some part of the pillow block, or other detail that holds the brass in its place. Brasses are usually made as light as possible to 55 save material, and it is a very easy matter to spring them in fitting up. If they are so sprung it is of no use to refit the bearing itself, because that does not cure the trouble. It will continue to bear badly until worn out if the cause which springs it is in existence. Get the spring out first, and then refit the bearing, and there will be no trouble. Chronic heating in brasses is almost always caused by this defect badly fitting brasses. Another cause is, as stated, dirt, pure and simple. This need not be like sand or gravel to give trouble. Sometimes dirt gets in with the oil. All oil should be strained through a cloth, no matter how clear it looks. There is a great deal of dirt in lubri- cating oil ot the average quality, as engineers find who strain it. Dirt also gets in through 56 carelessness. Any work done on a floor over an engine shakes dirt down upon it at some time or other, and all floors over engines should be ceiled absolutely dust proof by laying paper between the planks. Imperfect lubrication is also a source of difficulty with bearings, though, as a rule, there is oftener too much oil used than too little. 57 CHAPTER X. ADJUSTMENT OF BEARINGS. Another, and perhaps a by far too common cause of trouble with bearings, is improper ad- justment of them; that is to say, to the friction of the load proper is added the friction caused by excessive tightening* of the bolts and nuts, or gibs and keys. It is easy to see, we think, that the office of a bearing is simply to hold the detail in its place while it is at work. A gib and key will not only do this, but it will also permit an engineer to take up a bearing as it wears, in other words, make it larger or smaller. Now, this is not a virtue, by any means, but a defect, for it gives an opportunity for careless men to do mischief through want of judgment. Men who do not think, so soon as they hear a pound or a noise about an engine, immediately accuse some bearing and go at it with a ham- mer or a wrench, and tighten it up. Bearings on an engine which is in line and in good or- der seldom require any attention of this kind. It is really surprising how long they will run without being touched in any way. We know of stationary engines doing heavy duty which have not had the crank-pin bearing touched in three years, and from which not a sound comes. It is the same with the main bearings; where everything is in good order they do not want any tinkering, and the best evidence an engine can give that it is not in order is noisy action. We know of some stationary engines that run at high speeds (240 revs, per minute constantly), yet no one would know they were running if. they turned their back upon them. They are actually and absolutely noiseless. Not one penny has been spent upon them for repairs in over two years, and no tinkering of any kind has been done upon them. Facts like these prove our assertion that perfectly ad- justed bearings and good workmanship com- bined will run satisfactorily for long periods. Unfortunately, not every engine is the best of its kind, and engineers can not always control the conditions. In other words they can not rebuild the engines, and we are willing to ad- mit that there are some engines which it is very hard to "get the pound out of." Let it be borne in mind just what the office of a bearing is, however, and much can be done to lessen the annoyance of pounding. Reference will be made to this further on in this work, as some of it is due to faulty valve setting. THE VALVE AND GEARING. Having now gone from the cylinder head to the main shaft of our engine, and briefly re- 59 viewed the principal details, let us go back to the steam chest again and look at the slide valve and the valve seat, as shown in fig i. Let us compare them and see what relation they bear to one another. The office of the valve is to open and close the ports alternately, as we all know, and if it is rightly made, it will do this unfailingly, but it too often happens that it is not rightly made, but is simply a cast- iron box stuck in the steam chest anyhow, as we may say. Sometimes, in small shops (and in large ones for that matter), foremen get notions in their heads that a slide valve was never made until they got one up, and the man who is afflicted with an engine of this kind has a big bill for fuel. At other times engineers themselves get notions as to exhaust lap and exhaust lead, and cut away or add to slide valves that were in perfect order before they meddled with them. We have no theories of any kind to propound, and no hobbies to ride, and shall illustrate, therefore, only the usual defects and the methods of curing them, leav- ing every one to adopt or reject them as they see fit. Figs, n, 12, 13, show the slide valve in various positions: the first one at mid-stroke, where it covers both ports; the second with lead, or just opening the port; and the third 6o with the port full open. This valve is shown as having line and line exhaust, that is to say, without lap on the exhaust side. The result is shown by looking at a, fig. 12, where the steam is passing out, as shown by the arrow; it has a free exit, to the extent of half the steam port nearly, when the crank is nearly on the center, but the exhaust began to open before the piston arrived at the end of its stroke. This is just the point where, it is claimed by those who are p 1 1 1 1 1 '//^y////^ \ v 1 H 62 in favor of inside lap on a slide valve, that an error is made, because it lets the steam escape before it has done all the work that it can. In some measure this is true, because every inch that a piston travels under pressure gives power, but the diagram, fig. 14, shows, to our mind, that the steam on the last quarter of the piston stroke does very little work indeed. It is at a comparatively low pressure, having been expanded through the cylinder, and the force exerted by it is spent upon a crank whose radius is shown at a, fig. 14, and not in a direct line, or at right angles with the line of motion, but at a very obtuse angle, as shown by the dotted lines, so that the effort to turn the crank is absorbed to a great extent before it reaches the shaft itself. Suppose we do add inside lap, as shown by the dotted lines at b, figs. 12, 13, to the extent of half the steam lap, then we re- tain the steam in the cylinder until the piston has completed its stroke; we follow it up with spent steam until it begins the re- turn stroke; we get a full exhaust of the spent steam through the steam port, but we lose nearly half the area of the exhaust port in the valve seat, so that, as shown at tical bends are made in them. Air collects in the tops of these bends and stops the water quite as effectually as a block of wood could. It lies on top of the water as wood floats on it, because it is very much lighter, and is com- pressed so much by the action of the plunger that it resists the main flow of the current, and the water surges back and forth in the cham- bers. This is fully shown in an air chamber, which is a well known adjunct to pumps, both single and double-acting. If metal valves are used for the lift or force sides, they should be carefully examined, from time to time, to see that they are tight on their seats, and lift squarely, and seat fairly. An unsuspected source of trouble is often found in the seats of valves. These last are brass bushes driven into cast-iron chambers. Sometimes these cham- bers are bored out for the valve seats, and very often they are not, but taken as they come from the foundry. In work of this character it is not uncommon to find leaks. The seats also work loose in the castings, and leak from that cause. Another difficulty with pumps is found in the lift or rise given the valves. Quick working pumps require very little lift to the valves on either side, but the most should be given on Ill the force side. Divide the diameter of the Valve by four; this will give a lift equal to the area of the opening in the valve seat, which is all that can be delivered to the pump barrel. A two inch valve, then, should lift only half an inch, and even this will be found too much in some cases. Plunger pumps that run at high speed, or over 100 feet per minute, are very apt to pound violently and make a great deal of noise. This can be overcome wholly by sim- ply coning the end of the plunger to an angle of 30 or 40 degrees. Put the plunger in a lathe and bevel the end off, and there will be no more pounding. The reason for this is not easy to find. Pumps are still used in many places for feeding boilers, but in a majority of cases in- jectors are used. These last are simply man- aged, and the fullest directions are sent with them by the manufacturer. If they are follow- ed implicitly there will be no trouble, but if persons undertake experiments on their own account they must not blame the apparatus. These are succinctly the principles govern- ing the action of condensing engines and the pumps by which they are worked. All pumps act upon the same principles as those previ- ously alluded to. Whether the detail which ex- hausts the air from the water supply pipes is a scroll, a screw, or a fan attached to a shaft and 112 rotated by it, as in a centrifugal pump, whether it is a simple bucket or a plunger, the fact is the same: the air must first be removed before any water can get to the pump, and the special de- tail, the fan aforesaid, or the bucket or plunger which forces the water out of the pump cham- ber has no direct influence upon drawing the water itself. It may-be that we have reiterated this too often, but we think not, in view of the fact that we were told quite recently by a per- son in charge of a pump that the suction valves were so heavy that the plunger could not lift them. It is very hard to get rid of notions and ideas; the more erroneous they are the more difficult it is to abandon them. This is our apology, if any is needed, for insisting upon the facts laid down as regards the action of pumps. Also, let us say here, that in previous chapters we have stated that water would rise only 32 feet in a pipe in a perfect vacuum. We should have said in a working vacuum, which is far from being a perfect one. The mean pressure of the atmosphere within its known limits is 14.7 pounds per square inch, which corresponds to a column of mercury (supports it) 29.9 inches high, or will support a water column 33.9 feet high at the sea level. These are the exact figures, but we have all along in this work preferred to deal with every day results and figures, rather than submit mere cut and dried recitals of tabulated details. Dismissing the steam engine and its belong- ings, with the bare review of its functions and management which has been possible in the assigned limits of this work, and assuming that we have a new plant to start for the first time, let us mention some details that are of great im- portance. 114 CHAPTER XVII. STARTING A NEW PLANT. New engines and boilers should be started with great care; this statement applies particu- larly to the boiler. If the latter is large, the fire under it should be started at least three days before the boiler is actually needed for work, and the fire should be very small indeed at first. For the first day no attempt should be made to raise steam, and the fire should not be urged in the least. The water should be al- lowed to get "hand-warm" only, and be kept at this temperature for twenty-four hours. The reasons for this must be apparent with very little thought. Everything is cold on the start, and all the dimensions will be greatly changed by heat, and unless great care is taken at the outset much injury can be done to the brick work setting and the boiler itself. For the second day the temperature may be increased to nearly the boiling point, but the fire should not be driven. The furnace doors must be kept shut all the time, and the ash-pit doors also, the amount of draught and of fuel being governed so as to keep the boiler from making steam. On the third day the boiler may be allowed to make steam, but the pres- sure must be brought up gradually, and the fire H5 upon no account forced. The furnace doors must be always kept closed as before. As the pressure rises above the atmosphere, open all the steam connections and allow the steam to warm the pipes thoroughly before putting greater pressure upon them. Do not close any valve with a rush when the pressure rises to the working point. The boiler should be full of water on the start, three full gauges, so that while the pres- sure is still low the boiler can be blown down through the blow-cock to get rid of all the rubbish that has accumulated in inaccessible corners. Open the blow-cock steadily, not with a twitch of the handle, and blow down to two gauges. This should not be done until a few minutes before starting the engine; the feed will not be needed for a few minutes then, and in that time all the feed-pipe connections will warm up and expand equally. Try all movable joints, handles, cocks, safety valves, everything in short, to see if they work properly, and examine every valve and stuffing box personally to see if they have been packed properly. Look carefully to all the joints un- der pressure, and do all this before a working pressure is raised; keep up this inspection from time to time as the pressure increases. On starting the engine, open all the cylinder cocks to blow out the condensed water which has accumulated in the pipes and cylinder. This is imperative, not only to get rid of the con- densed water, but to blow out the sand, chips and minute filings, that can be removed in no other way. These have accumulated in the engine while it was being built and erected, and in no other way can they be so effectually removed. Move the live steam valves, so that steam is blown through both ends of the cylin- der for the purpose mentioned. Before turning the engine over the center for the first time make absolutely sure that every- thing is clear ; give the engine steam easily, and run the crank over on the three-quarter position; then give steam the other way, if there is hand gear which admits of it, and drive the crank back again. Do this carefully, and before the engine is finally allowed to pass the center shut the throttle entirely, so that if any- thing is wrong or anything carries away, the mischief will be confined to one stroke. The flywheel will carry the engine over the center. An engine should be started the first time under very moderate pressure ; five pounds should be enough if the engine is properly made. No power is needed, and the only points to be established are, whether every- thing is in apparent good working order. If possible, do not lace any main belts until after the engine has been tested. There is no knowing 1 what may have to be done, for mistakes are possible to all until the en- gine has been tried. If indicator attachments are on, take friction diagrams at this time with the unloaded engine, and see what it requires to move itself. Do the same* when the main belts and shafting are on. without the machines, and valuable data will be had for future reference. As to the engine con- nections, the main bearings, crank-pin, and cross-head end, should be left perfectly easy. If they thump slightly, it does not matter when the engine is running slowly. Thumping from loose connections is very different in sound from pounding for want of proper ad- justment, and the careful and experienced engineer will detect the difference at once. In all that has been said, we have endeavor- ed to inculcate the idea that, above all other things, the most watchful care and supervision is needed on first starting a new engine and boiler. On such occasions a tremendous change is introduced. Cold metal is made hot, and, in this transition alone, inconceivable force is generated. It is none the less power- ful because it is invisible, and makes itself known only by rupture. Boilers are made n8 leaky by careless handling on the start which were perfectly tight and well made, and strains are set up within them by forcing them, which materially affects their life. The same is true of the brick-work, if the boiler is so set, and it is for this latter, primarily, that we advised three days moderate heating of the boiler upon starting it. It takes, or should take, a long time to heat a brick wall alike so that it all goes together, and three days is none too long. If these directions are followed, properly built engines and boilers will perform well from the start. There will be no running back and forth to the shop, or calking leaks, re- making joints, or any sort of fuss. There will be that harmonious straight-avvay condition of affairs which mark the difference between a man who knows his business and one who does not. From what has been said in preceding pages it is apparent that to be a successful engineer requires care and skill of the highest quality. The attention necessary to keep a steam plant up to its best condition all the while must be unremitting, otherwise great loss results. It does not follow from this that an engineer should be hopping around from engine room to fire room, or running here and there with a squirt can, or in a fuss generally ; what we mean to inculcate is that an engineer should keep the run of his plant in his head at all times, and not suppose things are all right because no accident has happened. Accidents never happen to careful men ; they only happen to persons who suppose instead of knowing, as far as human foresight can go. Mysterious boiler explosions, mysterious flywheel burst- ing, mysterious anythings about steam engines, could, if all the facts were known and the naked truth were told, be traced to a condition of things previously known to some one which was willfully neglected. "Let well enough alone," is a good maxim in an engine room, but this does not mean that bearings are never to be examined, boilers never cleaned, or never examined for defective braces, and the whole routine of an engineer's duties neglected. For ten hours daily, at the least, an engineer must keep watch of his engine and boiler, for things go wrong when they are least expected to. In a factory where hundreds of people are em- ployed, a very small matter to an engineer may precipitate a panic which will cost many lives, and it is for him to see that it does not occur through his carelessness. We were in an en- gine room fire room, rather once when a rivet blew out above the water line, and made a great fuss. A youth who was in the place I2O started for the door, shouting that the boiler had burst, but he did not get far enough to frighten others before he was caught by the collar and a little advice given him that was of service. When a rivet blows out it is a simple matter to whittle a pine plug and jam it in the hole, either above or below the water line, and it is not a bad idea to have plugs handy for this purpose. It is not uncommon for rivets to blow out. Another point that an engineer should bear in mind is that the engine is upon no account to be stopped in working hours, unless it goes to pieces, direct orders are given, or danger to life and limb is imminent. No engineer should stop a factory engine where goods are turned out by the piece, or by the yard, or any other quantity, for a hot bearing, or because some detail of the engine will be ruined if kept run- ning. The cost of most details of an engine is slight, but if the detail costs a hundred dollars it is better to lose it than a thousand dollars' worth of work, or two hundred dollars' worth of time. This is particularly the case in places where power is sold to tenants. Every revolution of the engine means some fractional part of a dollar to them, and the stopping of an engine for some trifling, or possibly serious, expense to the landlord, might mean ruin to a tenant, 121 who would, perhaps, depend upon that very half hour to complete a contract in a given time. Upon trifles, as we call them, very great events depend sometimes. We repeat again, never stop an engine in working hours except for the direst necessity. Also, never start an engine after it has been stopped without a direct written message, or direct personal notice, from the man in charge. Suppose nothing. It is a serious business to neglect either of the precautions above men- tioned 122 CHAPTER XVIII. THE HIGHEST QUALITIES DEMANDED. Finally, let me say, in conclusion of this work, that the duties of an engineer worthy of the name call for the highest qualities, and are not to be lightly undertaken, or held in low es- teem. A man who stops and starts an engine is not an engineer, and has no pride in his business, because he knows nothing of it ; he does not wish to know any more than that opening the throttle lets steam into the chest. But we should not be discouraged or care- less ourselves because such men get places, to the exclusion of their betters. There are usurpers everywhere. Quack doctors abound, so do quack ministers and shyster lawyers. It would be quite as logical and sensible for skilled professional men of these classes to give up trying to rise as it would be for an engineer to follow the same course. Knowledge of our business is paid for always, but ar. engineer must know where to find the best market for his services, exactly as every other man must who has something to sell. A dentist, let us say, settles in a certain locality and does not thrive. He does not immediately accuse his profession as the cause of his trouble, but he says that there is no business in that place, and 123 searches until he finds one that is better. " Knowledge is power" is as true to-day as ever, but there are some places that are better than others to sell it in. If an engineer spares no effort to improve himself, and studies first principles so as to know where to look for the cause and cure of troubles never encountered before, he is a bet- ter man for a steam user than a mere stopper and starter who does not wish to learn. Some- where there is a steam user looking for him, and it is the engineer's business to find a place where he is paid for his work. We need only look around us to see engineers who have good homes, are socially esteemed, and are bringing up families to be a credit to them- selves and the State. These men started from small beginnings, and were careful, prudent and anxious to learn. They did learn, and that is why they thrived. THE MAN HIMSELF is THE FACTOR. It is not the business which a man follows that keeps him down or lifts him up ; it is the man himself in every case, and it is well to bear in mind that a man can not be an engi- neer, or a lawyer, or a doctor, or anything else, at a bound. Long service, patient waiting, dis- appointments, reverses, learning through them and learning by success also all these have 124 their perfect work. No faithful service is ever lost. If a steam plant is in perfect order and running lower than others in the vicinity be assured that if the employer does not see it, others do, and perhaps when we least expect it we may get a call to go elsewhere with manifest benefit. There are many things conducive to success in engineering, as in all other callings which mankind follow, and none of these has more effect in business intercourse than a pleasant address. Engineers are commonly supposed to be " rough men," but after living and asso- ciating with them for forty odd years, all over the United States, and of all classes, locomo- tive, stationary and marine, we have found fewer engineers of violent manners and rude bearing than we have in other professions. Some may feel that civil speech has little to do with success. It has everything to do with it, for as a rule, even if men are skillful in their special line, we will not encounter them if we can avoid it when they greet us roughly and are surly in their dealings with us. LASTLY. In these United States no man is above his calling or beyond it. If he is a man in all that the word implies, he is independent of circum- stances and of conditions, and is always in demand. The trickster perishes by his own I2 5 sword. It does not take long to discover whether men are honest or the reverse, and once the verdict is given either way no one can escape the consequences. Not merely honest in the sense that he will not take what does not belong to him, but an honest man in a moral sense. And with this little sermon we say farewell. THE CORLISS EKGIHE. BY JOHN T. HENTHORN. AND MINIGEMENT OF THE CORLISS ENGINE. BY CHARLES D. THURBER. Uniform in One Volume, Cloth Cover; Price, $1.00. Table of Contents. CHAPTER I. Introductory and Historical; Steam Jack- eting. CHAPTER II. Indicator Cards. CHAPTER III. Indicator Cards continued; the Governor. CHAPTER IV. Valve Gear and Eccentric ; Valve Setting. CHAPTER V. Valve Setting continued, with diagrams of same; Table for laps of Steam Valve. CHAPTER VI. Valve Setting continued. CHAPTER VII. Lubrication with diagrams for same. CHAPTER VIII. Discussion of the Air Pump and its Management. CHAPTER IX. Care of Main Driv- ing Gears; best Lubricator for same. CHAPTER X. Heating of Mills by Exhaust Steam. CHAPTER XI. En- gine Foundations; diagrams and templets for same. CHAP- TER XII Foundations continued ; Materials for same, etc. Sent free by mail on receipt of price. Egbert P, Watson & Son, 150 Nassau St., N. Y, A FORTNIGHTLY PATER FOR ENGINEERS, STEAM USERS, AND ALLIED TRADES. TWELFTH YEAR, Contains useful matter of the class indicated by this work, and treats all subjects in a plain matter of fact way, without pedantry and without pretense. Two Dollars per Year Always in Advance. EGBERT P, WATSON & SON, 150 Nassau Street, New York. FOURTEEN DAY USE RETURN TO DESK FROM WHICH BORROWED This book is due on the last date stamped below, or on the date to which renewed. Renewed books are subject to immediate recall. _OJan'56CTX JAK 51993 865694 srrr OF CALIFORNIA