UC-NRLF 
 
 13 MD1 
 
 o 
 
 LJ 
 
oc 
 
 3 o 
 
 3 O 
 
 ELEMENTS 
 
 v OF 
 
 INDUSTRIAL HEATING 
 
 HOC 
 
 3 O C 
 
 O C 
 
 3 O 
 
 September, 1922 
 
 No, 
 
DEMAND for the educational 
 papers relating to principles 
 and practice of industrial heating 
 that we have issued, has led to 
 their revision and publication in 
 this convenient form, to better 
 meet requirements for a supple- 
 mentary textbook for shop train- 
 ing classes, vocational schools, 
 colleges, etc., as well as for the 
 man in the shop and others 
 interested in the subject. 
 
HE purpose of this booklet is to draw attention to essential factors governing the quality and 
 cost of products subjected to the action of heat in the process of manufacture, and the selection 
 and use of equipment, fuel or electricity necessary to produce better results at lower cost. 
 
 The influence of heat upon the quality and cost of practically all manufactured products, and the 
 comparatively inefficient methods in general use, indicate the necessity of developing a broader view of 
 the industrial heating problem. 
 
 The demand for better and cheaper products can only be met with better methods of heating and 
 handling, better equipment, and above all, men better qualified to understand and properly apply in practice 
 the simple principles of one of the oldest and most important, though indifferently practiced, industrial arts. 
 
 The views outlined are the result of years of practical experience with a great variety of heating opera- 
 tions and direct contact with actual manufacturing conditions. This has taught the necessity for a better 
 understanding of the underlying principles and purposes of industrial heating operations, the results of 
 which should be measured in terms of quality and cost of finished product not merely cost of fuel or 
 labor, mere tonnage of output, nor indication of temperature control. Such factors are too generally 
 accepted as determinative, although they bear about the same relation to the result sought in industrial 
 heating as in illumination or transportation. 
 
 CONTENTS 
 
 TITLE PAGE 
 
 Variety of Industrial Heating Processes ... 3 
 
 Factors Governing Quality and Cost of Heat-Treated 
 Products . 4 
 
 Relation of Temperature Control to Uniformly Heated 
 Product .6 
 
 Factors Affecting Time and Method of Heating and 
 Cooling ........ 8 
 
 Influence of Furnace Design on Cost of Production . 1 
 
 Selection of Furnaces . .. . . . .12 
 
 Illustrations of Practical Methods of Heating and 
 Handling, and the Variety of Furnace Designs 
 employed in the Metallurgical, Chemical, Ceramic and 
 other industries . 14-25 
 
 > TITLE PAGE 
 
 Scope and Limitations of Regenerative Furnaces . . 26 
 
 Relation of Type and Arrangement of Equipment 
 
 to Cost of Production . . . . . .28 
 
 Relation of Price of Fuel to Cost of Production . . 30 
 
 Factors Governing Selection of Fuel or Electricity . .32 
 
 Comparati ve Prices of Fuel on B. t. u. Basis . . .34 
 
 Comparative Heating Value of Industrial Fuel Gases . 36 
 
 Composition of Industrial Fuel Gases . . . .38 
 Utilization of Fuel Resources ..... 40 
 
 Data on Heat . 42 
 
 Copyrighted 1922 
 United States and Great Britain 
 
Variety of Industrial Heating Processes 
 
 HE variety of industrial heating processes is 
 
 rarely realized except by those directly concerned 
 with the development of improved methods of 
 heating and handling to meet the need for better 
 and cheaper products in the metallurgical, chemical, 
 ceramic and other industries. 
 
 The use of heat in practically every branch of industry 
 
 has naturally resulted in the development of different methods of 
 generating heat from fuel or electricity; many different methods 
 for the application and utilization of heat in the product, and 
 a great variety in furnace design and equipment for handling the 
 material to be heated or cooled. 
 
 The ever-increasing demand for better quality and lower 
 cost of product and improvement of working conditions for 
 the operatives directs attention to the ever-important question as 
 to the manner of applying heat to the product, which is so directly 
 related to quality, and the influence of methods of heating and 
 handling and design and layout of furnace equipment upon the 
 cost of production. 
 
 The fundamental principles affecting the application of 
 heat are fixed, but there is an untold variety in method of 
 applying these principles in different processes to meet the great 
 variety of manufacturing requirements and plant conditions. 
 
 In certain lines of manufacture, experience has determined the 
 method of heat application and the physical or mechanical 
 requirements of the process, which in a large measure influence 
 the type, size and general arrangement of furnace equipment and 
 the form of fuel or electricity to employ for generating heat. 
 
 The latitude for improvement is frequently confined to re- 
 finement in design of furnace and auxiliary equipment and in 
 methods of generating or utilizing heat and handling material to 
 be heated and cooled, etc. Often there is apparently little room 
 for material improvement without a radical change in the nature 
 of the manufacturing process. Frequently, the heat-treatment 
 process is conducted with methods and equipment which are 
 passable under certain conditions but are not really suited to the 
 operation in hand, making it exceedingly difficult to materially 
 improve the quality or decrease the cost of production. Such 
 conditions generally warrant the policy of ignoring precedent, 
 usually the result of circumstance, and starting afresh from the 
 fundamentals of the problem. 
 
 The "human element" is the ultimate controlling 
 factor, and bears about the same relation to the heat-treated 
 products of the shop that the cook bears to the heat-treated 
 products of the kitchen. The common and wasteful practice 
 of delegating to unskilled men the control of important heat- 
 treatment processes, which so frequently affect subsequent 
 operations and value of the finished product, must be corrected 
 in the practice of the future. 
 
 The need of the moment is for improved methods of 
 heating and handling and competent operatives or super- 
 visors who understand the principles affecting the generation, 
 application and transfer of heat, and who can properly employ 
 furnaces, fuel or electricity, pyrometers, etc., as tools for the 
 conduct of the ever-important work of " heat application. " 
 
 The variety of methods of heating and handling, and 
 
 design and layout of furnaces that may be used in the various 
 industries, is generally unknown to those not familiar with the 
 wide range of processes, manufacturing requirements and plant 
 conditions, and the possibility of effecting improvement in one 
 line of manufacture through experience gained by practice in 
 others. 
 
 To the average man, a furnace means that piece of necessary 
 equipment in the cellar of his house which is more or less a 
 nuisance and expense for six to nine months of the year. 
 
 The furnace horizon of the blacksmith extends very little 
 beyond the smith fire which serves for general forging or heat- 
 treating of the small pieces of metal to which it is adapted. 
 
 The drop forger sees little more than a comparatively small 
 uncomfortable furnace with an uncovered opening in front, 
 through which the material to be heated is introduced and with- 
 drawn. 
 
 The smith accustomed to heavy forge work and steam hammers 
 or hydraulic presses is more at home with the single-door or 
 multi-door forge furnace, and occasionally with some type of 
 large annealing or heat-treating furnace. 
 
 The foundryman engaged in the production of iron castings 
 is concerned primarily with the cupola and core oven, though he 
 may be familiar with air furnaces for melting, and annealing 
 ovens if malleable iron castings also are produced. 
 
 The brass founder is interested in little beyond his crucible 
 pit fires and core ovens, though in some instances he may be famil- 
 iar with the tilting type of crucible or reverberatory melting 
 furnaces, or with electric melting furnaces. 
 
 The rolling mill man producing brass or copper products is 
 familiar with coal or coke pit fires for melting brass in crucibles, 
 or perhaps with the tilting type of electric furnaces in which the 
 heat may be released through induction, or through some form of 
 arc or resistance. He is also familiar with large annealing muffles; 
 and, if engaged in the manufacture of metal specialties, with other 
 types of furnaces for annealing, brazing and other operations. If 
 he manufactures brass or copper wire or tubes, he will undoubtedly 
 know various types and sizes of billet heating furnaces, and even 
 scaling or cake heating furnaces if producing sheets or plates. 
 
 Those engaged in the production of copper are primarily 
 interested in smelting furnaces for reducing the ore or in large 
 reverberatory furnaces for refining the metal. 
 
 Those concerned with the manufacture of steel are familiar 
 with furnaces of quite different designs, there being a wide variety 
 to meet the requirements for steel sheets, wire, rods, pipes, etc., 
 starting with the blast furnace and followed by the open hearth, 
 converter, or electric melting furnaces, the soaking pit, billet 
 heater and other units to meet the heating, forging, welding, and 
 annealing requirements. 
 
 Even steel mill men producing structural products are 
 frequently unfamiliar with the extremely wide variety of furnaces 
 for heating, forging, and heat-treating required in the fabrication 
 of alloy steels into manufactured products, ranging from heavy 
 ordnance to the smallest needles. 
 
 The production manager in the large automobile or similar 
 plant fabricating large quantities of different kinds of metal in 
 assorted sizes has a broad range of vision in the industrial heating 
 field, which includes many of the furnaces previously referred to 
 and various types of other furnaces more or less special in nature 
 to suit production requirements for normalizing, hardening, 
 carbonizing, annealing, and miscellaneous heat-treating operations. 
 
 The chemical engineer is confronted with some interesting 
 heating problems, which require a wide range of furnaces adapted 
 to the special nature of his processes and the manufacturing 
 requirements and plant conditions governing his practice. 
 
 The outline of principles and illustrations of their 
 practical application in different lines of industry, which 
 follow, have been compiled in the belief that the information will 
 be of benefit to those interested in industrial heating processes, 
 by indicating the opportunities for improving the quality and 
 decreasing the cost of production by better methods of heating 
 and handling, which frequently result from proper selection and 
 use of "FURNACE AND FUEL TO SUIT CONDITIONS." 
 
Factors Governing Quality and Cost of 
 Heat-Treated Products 
 
 HE importance of the application and utiliza- 
 tion of heat in manufacturing processes should 
 lead to a thorough consideration of the factors 
 that govern the production of heat-treated prod- 
 ucts and the selection and use of furnaces and 
 fuels as a means to that end. 
 
 Heat in one way or another affects the quality and 
 cost of practically every manufactured product. Its in- 
 fluence is far-reaching, particularly in the manufacture of metal 
 products, yet it is doubtful if there is another manufacturing 
 process as important as industrial heating so generally neglected 
 and misunderstood. 
 
 The selection of methods, equipment and fuel is fre- 
 quently made difficult by widely divergent recommendations, 
 based on opinion or prompted by commercial interest, which 
 cloud the real problem. 
 
 Many essential factors must be considered in the problem 
 as a whole, including intangible values which cannot be definitely 
 measured on account of evolution in the art and the ever-changing 
 economic, industrial and manufacturing conditions. 
 
 Essentials may be overlooked in abstract consideration 
 of related details, such as fuel values, methods of releasing heat, 
 temperature control, furnaces, burners, pyrometers, control 
 devices, etc. 
 
 V 
 
 The problem boils down to selecting the combination 
 
 of raw materials, methods, production equipment and facilities 
 and personnel, which, when properly adapted to individual 
 manufacturing requirements and plant conditions, will most 
 nearly accomplish the result sought, i. e., the production of 
 quality product at minimum cost. Every detail, technical or 
 otherwise, is but a means to this end. 
 
 It is as much a waste for the manufacturer to use the wrong 
 form of heat energy (fuel or electricity), regardless of its cost on 
 the basis of " heat unit value, " as it is to waste the right form of 
 heat energy or raw material in furnaces improperly designed, 
 constructed or operated, regardless of heat balance. 
 
 Selection may be simplified by consideration of the factors 
 outlined by the chart on page 5, which govern every industrial 
 heating operation, whether it be baking a loaf of bread or melting, 
 forging, or heat-treating tons of steel. 
 
 Quality and cost of finished product are the basic factors. 
 
 .There are many contributing factors, including the human 
 element, any one of which may influence the ultimate result. 
 
 Consideration of factors affecting quality must include 
 the manner of cooling as well as heating, and the effect of 
 atmosphere. Uniform heating prepares material' for uniform 
 heat-treatment; the adjustment of the structure and final set in 
 cooling actually determine the uniformity of the heat-treatment. 
 
 Uniformity of heating and cooling is governed by factors 
 many of which are not generally considered. Control of 
 furnace chamber temperature is but one of the factors influencing 
 uniformity of heated product. Of primary importance are 
 uniform application of the heating or cooling medium to the 
 surface of each piece of the charge, the rate of heating or cooling, 
 
 degree of saturation and the effect of atmosphere inside and out- 
 side the furnace. 
 
 Temperature must be considered with the element of 
 time and the surface exposure of each piece to the heating 
 and cooling mediums. The relation of surface to mass is 
 the basic factor determining time of exposure, other conditions 
 such as conductivity of material, rate of heating or cooling, etc., 
 being equal. The shape of the individual pieces, affecting the 
 relation of surface and mass, or a mere change in shape without a 
 change in weight or composition, may dictate changes in the 
 method or rate of heating, cooling or handling. With highly 
 figured dies or irregularly shaped forgings or castings, it is 
 desirable to heat slowly to prevent overheating the thin sections 
 or sharp corners, which, by reason of large surface in propor- 
 tion to mass, are heated and cooled more rapidly. 
 
 The all-important work of properly applying heat to 
 the product is frequently neglected by consideration of 
 related conditions, such as "temperature control," "fuel values," 
 methods of releasing heat through combustion or electricity, 
 or methods of indicating or controlling temperature. 
 
 The cost of heat energy in the form of fuel or electricity is 
 frequently accepted as a standard by which to measure heating 
 cost, but it is of little value without consideration of other 
 factors determining quality and ultimate cost of product. 
 
 Fuel cost, which includes quantity consumed as well as price, 
 is but one item in the final cost of heating, just as it is but one 
 
 item in the final cost of illumination or transportation. In all 
 cases, the design, operation and suitability of the appliance, 
 whether it be a lamp, boiler, engine, motor truck or furnace, must 
 be considered in relation to the quality and cost of the ultimate 
 result. Fuel consumption records bear about the same relation to 
 manufacturing or transportation costs that pyrometer records 
 bear to quality of product. 
 
 Industrial heating results cannot be measured, as in power, 
 illumination or transportation, by definite standards, such as the 
 horse power hour, kilowatt hour, candle power hour, ton mile, etc., 
 because of the many variable factors influencing the quality and 
 cost of finished product. 
 
 Cost per unit of given quality not cost of fuel, of labor, 
 of tonnage output, nor indication of temperature control 
 is the determinative test of an industrial heating opera- 
 tion. 
 
 The human element cannot be eliminated by devices 
 which govern supply of heat energy, except in rare cases where 
 the manufacturing routine does not vary in essential detail. 
 Variations in size, shape, weight, quantity, rate of flow, time of 
 exposure, composition of material, or in the heating or cooling 
 process, require skill and judgment on the part of the operative. 
 Recognition of the difference between control of temperature and 
 means of releasing heat on the one hand, and control of other 
 essential factors related to finished product on the other hand, 
 should cause appreciation of the importance of the human 
 element. 
 
 Low first cost of material, or fuel, or equipment, or labor does 
 not assure low cost of quality product. Improvement in 
 quality and decrease in cost, or both, will result only from a 
 proper co-ordination of all factors. 
 

 
 u. S 
 
 >- ^ 
 
 
 
 
 ^ 
 : 
 
 
 
 
 
 
 < z 
 
 
 
 
 
 - 
 
 
 
 z 
 o 
 
 5 
 ^ 
 
 
 
 
 : 
 l 
 
 I =3 
 
 -> o S 
 
 3 
 SG 
 
 1 
 
 jS 
 
 < r 
 
 p 
 
 o ^ 
 o: 
 
 " X 
 
 z o 
 2 g 
 
 
 
 
 t 
 
 ; 
 i 
 
 3 
 '- 
 '. 
 
 V) UI 
 
 Oi- 
 o. O ~ 
 
 X DC C 5 
 
 tj- S2 
 
 I 
 
 X 1 ? 
 
 t-v 
 
 Q 
 
 ? 
 
 1 
 
 < 
 
 5 
 
 OL _J UI 
 O < UI Z i 
 
 35 
 
 Z 
 
 IA 
 
 UI 
 
 > 
 P 
 
 UI 
 
 . 
 
 1 
 \ 
 
 Y &y 
 
 II 
 
 
 
 3 
 
 U. S - 
 
 X X 
 
 < 
 
 
 
 i 
 
 
 K O 3) Q 
 
 
 o 
 
 ^5 
 
 t? 
 
 
 ^ 
 
 
 j 
 
 UI IE UI 2 
 _1 OJ < IE - 
 
 
 z z 
 
 S < = S 
 
 Y 
 
 O 
 
 
 
 t 
 
 < Z 1 r 1 
 
 
 Z p 
 
 3 x a > 
 
 1 UI 
 
 u. f 
 
 ! z o 
 
 | 
 
 
 _j* < <rr 
 
 S o 
 
 z 
 
 Jir^J 
 
 in Q cc y 
 
 o 
 
 Joo 
 
 
 
 n!i! 1 1 
 
 V s sis! i ! 
 
 o o9 N 
 
 Z UJ3 
 
 3 ijo z h 
 
 o 3 J i- z 
 
 O 7 1 < ui 
 V UX 
 
 . xo. 
 
 8 
 
 ft 
 
 X O w ' < 
 
 n. o? s 
 
 - 1 -J -1 3 
 
 MU*T* 
 
 < * K 1 I 
 
 . S S f" ?" z 
 
 gzs Y s 
 
 "CJ r 1 , * 
 
 -i 'g| 3 y 
 
 0? 1 ~ 
 
 rCOMFORT 
 HEAT 
 LIGHT 
 
 ;5S 
 
 = = * 
 
 5zi g 
 
 >>s agK_j-^ 2 
 
 OF SUPPLY 
 IUIPMENT-1 
 
 _^_ 
 
 N ~l| DESIGN OF HEATING CHAMBER 
 r-MATERIAL IN t 
 
 LposiTION OF-J COMBUSTION ( 
 POSITION OF-H |NLET ANQ 0(J 
 
 L HEATING ELEN 
 PP_rREQUIRED IN PROCESS 
 -UNIFORMITY DESIRED 
 !FACE-|_ ExposED r-HEATING-i 
 SS T- ISED '0-L COOLING^ 
 MDUCTIVITY OF MATERIAL 
 
 ;REE OF SATURATION DESIRED 
 
 RATE OF l__rHEATING-i_ UF niiiL 
 RCULATION J '-COOLING-^ 
 rNEUTRAL 
 
 1 REDUCING 
 E | OXIDIZING 
 LCHEMICAL REACTION 
 ON 1 rTHERMAL UNIFORMITY OF 
 H DESIGN OF COOLING EQUI 
 
 aS H 
 \ a 
 
 ill! 
 
 V5S 
 
 UI _l < 
 
 o Q- a 
 
 Ms 
 
 2 * 
 
 : 5 L_T 
 
 (/) Q 
 
 ifi 
 
 iso|^ 
 3 <a2 
 
 5 ?"-"? 
 
 3F OPERATIVES 
 SPACE AVAILABLE rR 
 TRANSPORTATION FACILITIES W 
 NEIGHBORHOOD L T 
 ERATION TCONTINUOUS-l f-DAII 
 
 *TION t, NTERM | TTENT J LSEA 
 
 URNACES IN SHOP RELATION TO 
 
 E "M HANDLING-IT MATERIAL 
 ._n STORAGE """-FUEL 
 L AUXILIARY EQUIPMENT 
 
 OURCES OF HEAT ENERGY Cp^II 
 
 r- ELECTRIC rALTERNATING 
 r|ir|" RIC ^ : DIRECT CURRI 
 .ABLEH STEAM 
 AIR 
 "-HYDRAULIC r | NT ELLIGEI> 
 
 '-MORALE 
 
 E FACILITIES 
 rFUl 
 AM 
 rlNTERNAL-1 JJJ 
 OD INFLUENCE 
 -EXTERNAL- 1 
 S _rLEGAL 
 
 -ICONTRACTURAL IJ 
 
 | FAILURE 
 
 L ETC 
 J FURNACES AND AUXILIARY EC 
 HANDLING FACILITIES 
 
 MATERIAL IN STORAGE 
 LFUEL IN STORAGE 
 ^ FLOOR SPACE 
 EQUIPMENT _ RAW 
 
 MATERIAL L? R : ES , 
 
 2 = 5<5: 
 
 .' *~ t/1 Z O C 
 
 C UI 1 y p- 1- 
 C O r UJ < , 
 
 u, u-^ 
 
 i , i a. u. 
 1 u. 
 
 o * u> : 
 
 ? S < L 
 
 E ( 
 
 ' I 
 
 JO Z I 
 > Z I O = 
 
 
 
 
 t i K < i U 
 
 " V i 3 fe 
 
 . ll 
 
 ' Z u, O 
 
 n- O "i > 
 
 J 
 
 < <e 5 
 
 : 
 
 < 
 
 < U. < JK I ' '| 
 
 ou u 
 
 ^ ^ 
 
 U) ^ 
 
 i s 
 
 K 
 
 ^ UI 3 
 
 OT a n < L 
 
 o: o < o: : 
 
 J 
 
 : : 
 
 ? S y J 
 
 i J5 
 
 
 5 
 
 _J I j 
 
 J 
 
 ^ w 
 
 < 
 
 O < -J ui 
 
 c ; 
 
 i i ^ * 
 
 
 o 
 
 5 = 
 
 E * < 
 
 s * 
 
 > 
 
 9 !fi < * s 
 
 E 
 
 e " S> : 
 
 i 
 
 S 
 
 < H 
 
 
 J < 
 
 O > < 
 
 r" X ., o : 
 
 5 
 
 3 < B B : 
 
 : 
 
 x 
 
 7 1 T h 
 
 ? 1 
 
 y * 
 
 -1 O -1 
 
 t 1 < a. 2 
 
 : : 
 
 B Z 2 I 
 
 5 
 
 : Z 
 
 TI ' 
 
 : =P 
 
 : u- 
 
 III 1 
 
 L -T J 1 1 
 
 
 1 i I 
 
 
 
 ft 
 
 m 1 f\ 
 
 
 UI < 
 
 ui a: z 
 
 
 
 O S 
 
 
 
 z 
 
 
 u o 
 ui o Q 
 
 Q < UI 
 
 g ii 
 
 i-HEATING 
 
 L COOLING 
 
 
 
 ^5 
 
 =|i 
 
 o 
 
 z 
 
 :AL REACTIC 
 
 MEDIUM 
 
 zz p j 
 
 ui ui < o 
 
 Z Z ui o 
 ui ui z o 
 a: a i_j 
 55 T 
 
 _i 
 < 
 o: 
 
 DESIRED 
 
 UI 
 
 A 
 z z 
 
 rNEUTR, 
 J REDUC 
 
 1 OXIDIZ 
 
 z 
 
 III 
 
 o 
 
 J 
 
 ^ 
 
 o o o 
 
 ui ui t: 
 
 UI 
 
 i- 
 
 z 
 o 
 
 5i 
 
 5gx 
 
 
 
 r-HEATING 
 ""-COOLING 
 
 -PHYSICAL R 
 CHEMICAL R 
 
 ]- EXPOSED 
 
 riVITY OF MA 
 
 }F SATURATI 
 
 Xo 
 
 iS 
 
 < 
 
 V 
 5 J 
 
 </> a 
 
 > u 
 
 j 
 
 C 
 
 1 
 I 
 
 1 
 
 
 u. 
 
 
 
 
 y -I 
 
 I 3 
 
 
 
 O 
 
 TC. 
 
 Jj J^ 
 
 3 C 
 
 O Li 
 
 S 
 
 ii 
 
 0. 1. 
 
 5 
 
 
 O 
 
 3 a i" 
 
 Z t- 
 
 (J 
 
 1 - 
 
 
 
 
 
 H 3 < 
 
 o < 
 
 UI 
 
 o 
 
 
 
 
 t- 
 
 < in Z 
 
 oa 
 
 a 
 
 u 
 
 1 
 
 
 
 
 0: I 
 
 
 
 1 
 
 19 L 
 
 i 
 
 
 O 
 
 ui ' 
 
 1 
 
 
 
 z : 
 
 
 
 _l 
 
 E 
 
 
 
 
 
 
 
 t 
 
 UI 
 
 t 
 
 
 
 s i 
 
 i 
 
 
 T 
 
 H- 
 1 
 
 j 
 
 
 
 X t 
 
 > 
 
 
 
 g 
 
 
 
 
 T 
 
 
 
 l r 
 
 s 
 
 
 
 
 
 
 
 il 
 
 I 
 
 
 
 
 
 c 
 
 
 * 
 
 o 
 
 
 
 
 
 H 
 (j 
 
 
 88 
 
 >- > 
 
 h- t- 
 
 
 
 
 
 
 
 
 ^ j 
 
 I I 
 
 
 
 
 
 H 
 
 
 o 5 
 
 a: a: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 5 
 
 
 X X 
 
 on. 
 
 z z 
 
 3 3 
 
 
 
 
 
 5 
 
 
 V 
 
 J 1 
 
 
 
 1 
 
 ' 
 
 i 
 
 
 
 FESC 
 
 u. u. r: u. 
 o o<o 
 t_ i_ o: i_ 
 
 E t: ui t: 
 
 V 
 
 i 1 * 
 
 
 z g 
 
 < < o 
 
 EC E Ik MB! 
 
 zo . 
 
 KZ ' 
 
 3< i 
 
 Dz 
 
 3 P Q 
 
 o a z 
 
 T| 
 
 S I- 
 
 s ? 
 
 J I L 
 
 J=T* 
 
Relation of Temperature Control to 
 Uniformly Heated Product 
 
 NDICATION of "temperature control is fre- 
 quently accepted as evidence of a thermal condi- 
 tion suited to the production of a uniformly heated 
 product, regardless of the fact that indication of 
 uniform furnace temperature does not of itself 
 establish the uniformity of a heating or cooling 
 process. 
 
 Uniform temperature is necessary to produce uniformly heated 
 product, but heating a chamber uniformly and uniformly 
 heating a charge within that chamber are two distinct 
 matters. 
 
 Indication of temperature control is misleading without 
 consideration of other factors affecting the uniform heating or 
 cooling of the product, as outlined by the chart on page 7. 
 
 Of primary importance are the uniformity of heat ap- 
 plication to the surface of the individual piece, the time 
 of exposure and the rate of heating. Variation in product 
 may be caused by differences in furnace design, in placing of 
 charge in the chamber, in the time of exposure and in rate of 
 heating or rate of charging and discharging, resulting in differ- 
 ence in the application of heat to the charge, without any 
 indication of chamber temperature variation. 
 
 The ideal condition for the production of properly heated 
 product is nearest attained when the heating and cooling mediums 
 are uniformly applied to the entire surface of each piece or section 
 in the same manner, at the same temperature, at the same rate, 
 for the same time, in the same atmosphere, in equipment properly 
 adapted to the nature of the process, production requirements 
 and plant conditions. 
 
 The relation of indicated chamber temperature to heated 
 product is illustrated by the diagram on page 7. 
 
 The pyrometer chart is the record of a furnace in actual 
 operation. Although it might be assumed that a charge would be 
 uniformly heated in any furnace recording such a chart, there is 
 a marked variation in the heating of the charge in many of the 
 furnaces (1 to 11) even though the indicated chamber 
 temperature and time of heating are the same. The approx- 
 imate locations of the incompletely heated zones are shown by the 
 shaded sections. 
 
 The electric furnaces (5, 6, 7) are not exceptions to the 
 rule, for while they are alike in manner of generating and 
 controlling the heat, they differ in manner of applying it and 
 in method of handling the charge. 
 
 The product will likewise vary in uniformity in each of 
 these furnaces, depending on distribution of the charge 
 
 mass and surface exposed to heat although there may be no 
 variation of indicated chamber temperature or time of heating. 
 Diagrams "A" to "O" illustrate the variation from uniformity 
 resulting from different methods of distributing the same charge. 
 
 The rate of heat input must be intelligently considered 
 whenever there is a material variation in the mass or surface of 
 the pieces. Such variations may warrant changes in type or 
 design of furnace in order to control the rate of heating, time of 
 exposure, and placing of the charge in the chamber, independently 
 of the manner in which the heat itself may be generated, controlled 
 or indicated. 
 
 With the method of loading illustrated by diagram 12, it is 
 apparent that if the pieces of the charge were handled individually, 
 the one first placed in the chamber would be the last withdrawn, 
 and the piece last charged the first withdrawn. If all the pieces 
 of the charge were withdrawn when the one first introduced was 
 fully heated, and if this one had been introduced at approximate 
 working chamber temperature, there would be a difference 
 in time of exposure and degree of saturation of all the 
 pieces. If the pieces were placed close to or on top of one another, 
 
 the condition would be still more unfavorable. In such a furnace, 
 regardless of the uniformity of temperature or method of generating 
 or applying heat, a charge will not be heated uniformly unless it is 
 introduced and withdrawn as a unit, or unless the furnace and 
 charge are slowly heated together. 
 
 A cold charge placed in a hot furnace will absorb heat 
 rapidly, causing a drop in chamber temperature, whether it be 
 indicated by the pyrometer or not. The temperature drop and 
 time of recovery will be greater in a light furnace than in a heavy 
 furnace of the same type and chamber area. The greater heat 
 storage in the heavier furnace is of advantage in minimizing such 
 drop and time of recovery, in addition to effecting economy 
 in operation. 
 
 The temperature will also vary with the regularity of 
 input and outgo of material and heat; and with the relation 
 between the temperature, mass and surface exposure of material 
 in the chamber, and the temperature, mass and surface exposure 
 of material which follows. The actual temperature fluctuation 
 will decrease with the subdivision of the charge as the torque of a 
 gasoline engine or diagram of pump flow becomes more uniform 
 with an increase in the number of cylinders. 
 
 Determination of such factors as placing of charge in the 
 chamber, methods of handling, and suitable arrangement of 
 furnace equipment, etc., must include consideration of the 
 manner of applying heat to the charge, i. e., whether it be 
 transferred by radiation, convection or forced circulation of 
 chamber atmosphere. 
 
 While in both fuel-fired and electrically heated furnaces a great 
 deal of the heat is transferred by radiation, a considerable amount 
 is transferred by the circulation of the chamber atmosphere. 
 
 Heating by radiation alone is frequently undesirable in 
 fuel-fired furnaces of the muffle type or in electric furnaces in 
 which there is no forced circulation of the heating chamber 
 atmosphere, because of the difficulty of properly transferring 
 heat to the entire surface of the charge or individual unit, 
 and the consequent possible lack of uniformity. 
 
 Much of the heating that is supposed to be conducted 
 solely by radiation is actually performed by convection 
 currents brought about by a temperature differential, which 
 naturally creates motion and prohibits existence of the so-called 
 "quiescent atmosphere." The rate of circulation of such 
 convection currents is influenced by the temperature differential 
 and the relative mass and exposed surfaces of the receiving and 
 emissive bodies. 
 
 Frequently, as in the operation of electrically heated japanning 
 ovens or fuel-fired furnaces of the muffle type, in the chamber of 
 which there is but a slight temperature differential, it is necessary 
 to provide for forced circulation of the chamber atmosphere in 
 order to permit of efficient heat transfer, which would be unnec- 
 essary if the temperature differential were greater. 
 
 The continuous furnace (13) may be employed in a variety 
 of designs and methods of heat generation, with improved quality 
 of product resulting from uniformity of heat application, and 
 time and rate of exposure, and with lowered operating cost, 
 resulting from the efficient method of handling the product and 
 directly utilizing the heat. The field of usefulness of the con- 
 tinuous furnace, however, is determined by the size and shape of 
 the pieces to be heated, as well as by the quantity and regularity 
 of their flow. 
 
 Uniform heating is a relative term, 
 formity is rarely, if ever, attained. 
 
 Absolute uni- 
 
 Practical uniformity of heated product is secured only by the 
 proper co-ordination and application of all factors essential to 
 the selection and operation of industrial heating equipment. 
 
RELATION OF TEMPERATURE 
 
 TO HEATED PRODUCT 
 
Factors Affecting Time and Method of Heating 
 
 and Cooling 
 
 I ME the period required for 
 heating or cooling is a vital 
 factor in all processes involving 
 the application of heat. 
 
 The influence of the "time 
 factor" is not generally appre- 
 ciated in practice, due no doubt to a misunder- 
 standing of its importance and the many 
 variables that affect it. Unwarranted em- 
 phasis on "temperature control" as the es- 
 sential element in heating or cooling operations, 
 and "output," "fuel consumption," etc., as the 
 determination of cost, frequently leads to 
 neglect of the influence of the time and 
 manner of exposure and the rate of heating 
 or cooling upon quality and cost of the 
 finished product. 
 
 HEATED - 
 
 ~TFMPEIATURE-r REQUIRED IN PROCESS 
 
 * ^- I 
 
 UNIFORMITY DESIRED 
 
 CONDUCTIVITY OF MATERIAL 
 -RATE OF 
 
 -TIHE- 
 
 Control of time and rate of heating or 
 cooling is just as essential as control of temperature. 
 Time and temperature are so inseparably linked that it would be 
 well to associate the two as one controlling factor "time- 
 temperature." The use of such a term may tend to discourage 
 the usual abstract consideration of temperature without regard 
 to the time necessary to attain a given temperature; and to 
 encourage the thought that there are a number of factors in 
 addition to control of temperature that influence the uniformity 
 with which a given piece is heated or cooled. 
 
 The "time factor" is just as important in heating or 
 cooling operations in the shop as it is in the cooking 
 processes in the kitchen, where its influence is more generally 
 appreciated. The care with which a cook exposes a dish to the 
 heat ("heat application"), the attention given to time and rate 
 of heating, as in boiling an egg or baking a pie, and the good 
 results that generally follow the operation without provision for 
 automatic control of temperature, suggest application of the 
 same simple principles in industrial heating operations. Such pro- 
 cedure would do much to eliminate the irregularities so fre- 
 quently disclosed by physical tests, regardless of evidence in the 
 form of pyrometer records and analyses of material to show that 
 such irregularities should not exist. 
 
 The viewpoint of the engineer with reference to "the 
 rate at which heat CAN be transferred" to save time or 
 fuel or increase production, should be considered with the 
 views of the metallurgist or chemist in determining 
 "the rate at which heat SHOULD be transferred" in order 
 to effect the desired results in quality of finished product. 
 The result of the heat-treating operation should be expressed in 
 terms of quality and cost of finished product not cost of fuel 
 or labor, mere tonnage, nor indication of uniform chamber 
 temperature. 
 
 The ideal condition for the production of uniformly 
 heated product is nearest attained when the heating or cooling 
 medium is uniformly applied to the entire surface of each section 
 or piece and to each piece individually in the same manner, at 
 the same temperature, at the same rate, for the same time, 
 in the same atmosphere, in equipment properly adapted to the 
 nature of the process, form of fuel or electricity employed, 
 manufacturing requirements and plant conditions. 
 
 Temperature is a more or less fixed factor, determined by 
 the nature of the process and the physical or chemical require- 
 ments of the product to be heated or cooled. It should be con- 
 sidered with reference to the distinction between temperature 
 of the chamber or bath in which a piece is exposed and the 
 temperature throughout the piece itself, which is naturally 
 affected by the time of exposure and the rate of heat absorption. 
 
 ^-MEDIUM 
 
 rHEATING 
 ^COOLING 
 
 -DEGREE OF SATURATION DESIRED 
 
 I RATE OF L_rHEATING-i i-GASEOUS 
 
 rl -CIRCULATION- f '-COOLING-^ MEt " U *T-LIOUID 
 
 rAPPLICATIONT 
 
 H OF T 
 
 I HP AT 1 
 
 r THERMAL UNIFORMITY OF HEATING ZONE 
 DESIGN OF HEATING CHAMBER 
 
 MATERIAL IN HEATING 
 COMBUSTION CHAMBER 
 INLET AND OUTLET PORTS 
 HEATING ELEMENTS 
 
 "-POSITION OF 
 
 Fig. 3. Factors Determining Uniformity of Heating and Cooling 
 
 Time of heating is a variable factor and is influenced by the 
 manner of transferring heat to or from the surface of the piece; 
 the manner of loading, or exposure; the relation of one piece to 
 another and to the source of the heat; the difference between 
 temperature of the piece and the chamber or bath in which it is 
 exposed; the rate of circulation over the surface; conductivity 
 of the material of which the piece is composed; relation of the 
 mass of the charge to the chamber or bath in which it is exposed, 
 and other factors outlined by Fig. 3. 
 
 Rate of heating or cooling of material must be determined 
 with reference to the physical or chemical requirements of the 
 finished product, and with reference to the mass, shape, section, 
 exposed surface, and manner of exposure of the material, all of 
 which affect the rate at which it SHOULD be heated or cooled, 
 regardless of how fast heat COULD be transferred. 
 
 Rate of heat transfer affects the time required for heating 
 or cooling, and exerts material influence upon quality 
 of the finished product. It should be considered with reference 
 to the relation of the condition inside of the piece to the sections 
 near the surface. The influence of variable section, shape 
 or surface exposed upon the rate of heating or cooling 
 may necessitate slow heating or preheating in order that the 
 mass may be well saturated before being subjected to the final 
 temperature. Disregard of this point is responsible for the dif- 
 ficulties that frequently follow the practice of maintaining furnace 
 temperatures materially higher than that required in the stock. 
 
 The relation of the temperature of a furnace to the 
 temperature at the outside of a piece is not necessarily an 
 indication of uniform structure unless the time period has been 
 sufficient for thorough saturation and the stock properly exposed 
 to the heat. A difference in time of exposure or manner of 
 exposing two similar pieces at the same temperature may result 
 in a difference in structure. 
 
 The method of loading a furnace affects the time re- 
 quired for heating the individual piece; the uniformity of 
 structure of each piece throughout its mass; and the relation of 
 the uniformity of each piece to another. The influence upon 
 the time and rate of heating of the exposure resulting from a given 
 manner of loading and variations in the surface, shape and 
 section, may be illustrated by the diagrams in Fig. 4. 
 
 A round billet of given mass and weight placed on the 
 hearth of a furnace (A) will heat less uniformly and at a different 
 rate than if placed above the floor (B) to permit circulation under- 
 neath and uniform application of heat to the entire surface. 
 
. 
 
 A billet of the same mass and weight 
 in rectangular form will heat at a 
 different rate and to a different degree 
 of uniformity if placed in either position 
 on account of the relatively larger surface 
 in proportion to the mass at the corners, 
 which are the first to heat up and the 
 first to cool off. Even though the shape 
 of the rectangular billet may permit a 
 higher rate of absorption, it is obvious 
 that the difference in shape may ac- 
 tually suggest a lower rate of heat 
 transfer to permit a slow rate of heating, 
 in order to prevent a material difference in 
 temperature or time of exposure to that 
 temperature between the corners and 
 center of the mass. 
 
 The same billet in the form of an 
 irregularly shaped crankshaft or axle 
 with variable sections will heat in a 
 still different manner if placed in 
 either position on account of the difference 
 in surface and section. 
 
 A gear blank (D) will absorb heat at an 
 entirely different rate than the finished 
 gear (E), on account of the difference in 
 section incident to the shape of the teeth 
 and opening for the shaft keyway, etc. 
 
 A similar condition may result from the 
 relation of the pieces to each other, 
 
 even in a chamber that shows every indi- 
 cation of uniform temperature. Thus, 
 two rectangular pieces placed above the 
 floor, with provision for heat application 
 to all surfaces, will heat at a different rate 
 and to a different degree of uniformity 
 when placed in contact with each other(C). 
 
 Fig. 4. Illustrations 
 
 Heating in baths of molten metal, 
 salts, etc., is generally considered to be an 
 ideal method for operations in which 
 
 uniformity of heating and temperature control are essential 
 factors. However, the difference between heating in a molten 
 bath and in a "bath" of gases in the chamber of a furnace is 
 not as great as is generally supposed. The essential dif- 
 ference is in the influence of the bath upon the surface of the 
 piece; the manner of exposure and the resistance of the 
 bath to rapid transfer of heat. 
 
 The necessity for suspending the piece in a bath naturally 
 results in an ideal condition for proper "heat application" 
 to the surface, and eliminates many chances for error likely 
 to result from improper methods of loading in the chamber of 
 a furnace, particularly if it is desired to localize the heat, 
 as in hardening the cutting section of a tool. 
 
 Inequalities of temperature may exist throughout a 
 bath without indication by the pyrometer in its customary 
 fixed position, as may be observed in heating the bath from a 
 cold condition; in introducing a comparatively large mass of 
 cold material ; or when the input of cold material does not cor- 
 respond with the withdrawal of heated material. 
 
 The use of a bath does not eliminate the necessity for 
 considering the time element with reference to the factors 
 that influence the rate of heat transfer and uniformity of heating 
 or -cooling. A difference in relation of mass and surface, due to a 
 difference in shape or section, naturally affects the rate of heat 
 transfer and the time required for saturation. Thus, if a tap 
 were suspended in a bath of molten metal (F),the comparatively 
 thin sections would reach the temperature of the bath before the 
 center of the piece; and even though the center ultimately attains 
 the same temperature (G) ,the fact remains that the thin sections 
 have been subjected to that temperature for a longer time, which 
 of itself is frequently sufficient to create a difference in structure. 
 
 This illustrates the difference between uniform tempera- 
 ture in a furnace and uniformly heated product, and the 
 
 of influence of mass, surface, shape, and manner of exposure upon time 
 and uniformity of heating. 
 
 necessity for considering the influence of the factors that affect 
 time or rate of heating, as well as the factors that affect control of 
 temperature. Uniform heating is a relative term. Absolute 
 uniformity is rarely, if ever, attained. 
 
 The necessity for uniform time and method of exposure 
 and rate of heating or cooling to produce uniform product 
 indicates the need for a method of heating, cooling and handling 
 that will provide the same treatment for each piece. 
 
 "Batch heating" or cooling rarely results in uniform 
 product, regardless of the indication of uniform chamber 
 temperature, because of the lack of uniformity in method and 
 time of exposure and rate of heating or cooling. Variation is 
 generally disclosed by the structural difference between the pieces 
 at the outside of the charge and those at the center or bottom. 
 
 The advantages of the continuous furnace (L) in providing 
 a regular input and output of material, and control of the factors 
 affecting time and rate of heating, suggest application of the 
 principle of individual treatment whenever the manufacturing 
 requirements and plant conditions will so permit. 
 
 The difference between control of temperature in a 
 furnace and control of the application of heat to the 
 product is not merely a function of controlling the input of heat- 
 ing energy, whether it be fuel or electricity. The manner in which 
 the heat is applied to the surface of the piece, which very largely 
 reflects the design and method of operating the furnace, is of 
 paramount importance; and necessarily involves factors affecting 
 the element of time and rate of heating and cooling, which are 
 equally as important as factors that influence control of tempera- 
 ture. All of these must be considered in order to produce a 
 product as uniform as the pyrometer indicates it should be. 
 
Influence of Furnace Design on Cost of Production 
 
 HE ultimate cost of a finished product of 
 
 given quality is governed by the rate of production 
 and the cost of operation. 
 
 Because of the many variable factors governing 
 the quality and cost of product (page 5), the selec- 
 tion of furnace equipment (page 13), and the 
 selection of fuel (page 33), consistent efforts to reduce cost of 
 production require a thorough study of methods of heating and 
 handling adapted to specific manufacturing requirements and 
 plant conditions. 
 
 The influence of furnace design on the quality and cost 
 of product is illustrated by the diagrams on page 11, which are 
 examples from actual practice. 
 
 These diagrams illustrate the economy attainable by the 
 proper use of furnaces of suitable design, the selection of which is 
 based upon consideration of the manufacturing problem as a 
 whole. They also illustrate the economic weakness of the far too 
 common practice of basing selection only on price or form of fuel, 
 equipment or labor; quantity of output; temperature control, etc., 
 without reference to other equally essential factors affecting 
 quality and cost of the finished product. 
 
 There are no fixed standards to determine definitely the 
 proper form of equipment or fuel to use. Each must be 
 selected with reference to the other, and the suitability of the 
 combination to the heating process, manufacturing requirements 
 and plant conditions. 
 
 Frequently it is possible to better the quality of product 
 by adapting an improved method of heating or cooling to 
 existing conditions. A different type or arrangement of furnace 
 equipment may decrease labor, fuel and time; utilize the floor 
 space to better advantage; and provide more comfortable working 
 conditions. This generally results in an increased output and 
 lowered production cost even with the same unit prices for fuel, 
 labor and power, and without necessarily requiring new building 
 construction. 
 
 Requirements for quality should determine the method 
 of heat application. With this as a basis, the production 
 requirements and plant conditions should determine the type, 
 size, number and arrangement of furnaces; the form of fuel or 
 electrical energy; and the methods of routing and handling the 
 material. 
 
 It is a common but misleading assumption that control of 
 chamber temperature or of heat supply is synonymous with 
 control of heated product. On the contrary, control of the 
 generation of heat is not equivalent to control of the 
 application of heat, or to control of the uniformity of 
 product. Other essential factors (page 13) influence the 
 ultimate result. 
 
 The difference between control of heat as it is generated 
 in the furnace, and control of heat as it is applied to the 
 product in the furnace, must be considered with electric as well 
 as fuel-fired furnaces. 
 
 The comparative ease of controlling electricity, gas or oil is 
 frequently considered as the determinative factor in the selection 
 of heating equipment, regardless of a material difference in price 
 of other forms of heat energy or equipment. 
 
 Automatic control of the delivery of coal through stokers or 
 in powdered form; of gas, oil or steam through automatic valves; 
 or of electricity through various forms of regulating devices, 
 may result in control of the generation of heat, but does 
 not necessarily determine the use made of the heat. 
 
 The question of control involves control of the supply of 
 fuel or electricity to the furnace; control of supply of heat 
 to the working chamber; control of the heat as it is actually 
 applied to the surface of the product; and control of the 
 
 time of exposure and the rate at which heat is transferred 
 to the product. 
 
 Temperature is inseparably linked with time of exposure 
 and rate of heating. The time factor must be considered with 
 reference to the mass, surface and shape of the individual piece; 
 the method of loading; and the rate at which heat SHOULD be 
 transferred, as well as the rate at which heat CAN be transferred 
 to effect economy in fuel or time of heating. 
 
 The variable factors affecting time of heating, noted on the 
 chart, page 8, indicate the necessity of considering the time factor 
 with regard to the result sought in quality of the finished product. 
 The mass, surface, shape or section of the charge may suggest a 
 slower rate of heating, from the viewpoint of the metallurgist or 
 chemist, with regard to quality, than that possible from the 
 standpoint of the engineer to increase output or effect economy 
 in fuel. 
 
 The influence of furnace design upon the application and 
 utilization of heat is far-reaching. For instance, there is a 
 radical difference between the arc, induction, and resistance 
 methods of generating heat by electricity. There is even a 
 distinction within each of these broad groups. With the re- 
 sistance method, for example, the heat may be generated by 
 means of metallic resistors distributed on the walls of the furnace 
 or by other forms of resistance material the nature of which 
 prohibit such distribution. In each instance the furnace design 
 must be adapted to the method of generating and delivering heat 
 to the working chamber. 
 
 It is thus apparent that the practice of associating a given 
 form of fuel or electricity with quality or low cost of pro- 
 duction is misleading, unless there is definite reference 
 to the form of furnace and method of heat application and 
 utilization. 
 
 This fact may be illustrated by an unusual case which involved 
 a comparatively efficient type of furnace fired manually with bi- 
 tuminous coal, and three less efficient furnaces, one fired with oil, 
 another with natural gas and the third heated electrically through 
 metallic resistors with suitable control devices. With all other 
 conditions substantially alike, it was conclusively proved 
 that the quality and cost of the product were most favor- 
 able with the coal-fired furnace. 
 
 This example, however, does not prove that any one method of 
 generating heat is superior. In this instance the difference in 
 results was due to the better design and operation of the 
 coal-fired furnace, and the manner of applying and utilizing 
 heat in the product. In one case, the apparent disadvantage of a 
 crude form of fuel was overcome by an efficient furnace, while in 
 the others, the apparent advantages of the more flexible forms of 
 fuel, and particularly the advantage of electricity with control 
 devices, were neutralized by inefficient furnaces. 
 
 Other heat-treatment processes, manufacturing requirements 
 or plant conditions might prohibit any three of these methods of 
 generating heat; and the most expensive form of heat energy in 
 combination with a suitable furnace might show better results at 
 less cost. 
 
 There is no one form of fuel, electricity or furnace suit- 
 able for all conditions but there undoubtedly is a suitable 
 combination which, when properly used, will best meet the re- 
 quirements of each case. 
 
 Cost of production cannot be definitely expressed in terms of 
 .output per operative, per unit of fuel, time or floor space. It is 
 actually determined by quality and ultimate cost, which 
 include many intangible factors difficult to measure. It is greatly 
 influenced by the nature of equipment and the skill and in- 
 telligence of the operatives. Improvement will begin with proper 
 selection and use of furnace equipment properly adapted to the 
 heat-treating process, manufacturing requirements, and plant 
 conditions. 
 
 10 
 

 INFLUENCE OF FURNACE DESIGN ON COST OF PRODUCTION 
 
 EXAMPLES FROM PRACTICE. ILLUSTRATING THE ECONOMY EFFECTED 
 PROPER SELECT.ON AND USE OF FURNACES OF 1MPROVH 
 D-12 ADAPTED TO MANUFACTURE REQU.REMENTS AND ^AN? CONDONS 
 
 SMftLL DROP FORQE FURNflCE OPERATION 
 
 J 
 
 OUTPUT PER UNIT OF FLOOR SPflCE -37J& INCREflSE 
 OUTPUT PER UNIT OF FUEL-7ef INCREflSE 
 
 SMflLL DROP FORQE FURNflCE OPERflTION 
 
 OUTPUT PER UNIT OF FLOOR SPflCE- STT5y INCREflSE 
 OUTPUT PER UNIT OF FUEL- ZT^o INCREflSE 
 
 HEflT-TREflTINQ DROP FORQED 5TEEL PflRTS 
 
 OUTPUT PER MflN-IOOj& INCREflSE 
 
 EH 
 
 OUTPUT PER UNIT OF FLOOR SPflCE -I7fo INCREflSE 
 
 cn 
 
 OUTPUT PER UNIT OF FUEL - 33 J& INCREASE 
 
 CflRBONIZINQ fiUTOMOBILE PflRTS 
 
 KJVW 
 
 1700 
 IfeOO 
 1500 
 1400 
 1300 
 1200 
 1100 
 1000 
 
 1 
 
 
 / 
 
 * 
 d 
 
 /, 
 
 # 
 
 '/ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 t 
 
 
 
 I 
 
 / 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 V 
 
 fe 
 
 r 
 
 r^ 
 
 
 
 ~u 
 
 ^r 
 
 jfl 
 
 :E 
 
 "fl 
 
 " 
 
 r u 
 
 _L 
 
 L 
 
 IN 
 
 E 
 
 
 
 j 
 
 f 
 
 * 
 
 
 
 FU 
 
 Rr 
 
 4fl 
 
 :E 
 
 "E 
 
 - 
 
 DC 
 
 Tl 
 
 E 
 
 5 
 
 LI 
 
 ME 
 
 
 
 
 1 
 /> 
 
 > 
 ?' 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 1 
 
 1 
 
 
 
 
 i 
 
 /( 
 
 
 v/ 
 
 > 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 / 
 
 t c 
 
 C^ 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 3 
 
 / 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 (*-! HOURS FIRINQ TIME FOR FURNflCE"fl" 
 1*23 H u M "6" 
 ^MRTERIRL CHflRQED 
 
 TEMPERflTURE f TIME OF HEflTINQ PERIOD 
 FURNflCE "fl" 
 
 5MRLL DROP FORQE FURfNflCE OPERflTION 
 
 UNIT OF FLOOR SPflCE -eSOf. INCRCR8C 
 OUTPUT PER UNIT OF FUEL -47% INCREflSE 
 
 DROP FORQE FURNflCE OPERflTION 
 
 TIME FROM UQHTINQ FURNflCE TO STflRTINQ FORQINQ 
 DCCREfWE 
 
 OUTPUT PER HOUR -43fo INCREflSE 
 OUTPUT PER UNIT OF FUEL -^0% INCREASE 
 
 HflRDENINQ SNIflLL HIQH CflRBON STEEL PflRTS 
 
 OUTPUT PER MflN- I40^> INCREflSE 
 
 OUTPUT PER UNIT OF FLOOR SPflCE - 50fo INCREflSE 
 I 1 
 
 QUflLITy- REJECTIONS REDUCED FROM Sfo TO .07fcf. 
 
 flNNEflLINQ PRESSED STEEL PflRTS 
 
 OUTPUT PER MflN-75% INCREflSE 
 
 OUTPUT PER UNIT OF FLOOR SPflCE - 103 % INCREASE 
 
 cn 
 
 OUTPUT PER UNIT OF FUEL-Z5% INCREflSE 
 
 flUTOMflTIC END flNNEflLINQ OF SMflLL BRflSS TUBES 
 
 OUTPUT PER MRN- 200^0 INCREflSE 
 
 CD 
 
 OUTPUT PER UNIT OF FLOOR SPflCE -O% INCREflSE 
 QUflLITy- REJECTIONS REDUCED FROM 5^ TO If* 
 
 flUTOMflTIC END flNNEflLINQ OF LflRQE BRflSS TUBES 
 
 OUTPUT PER MflN- 275^0 INCREflSE 
 
 OUTPUT PER UNIT OF FLOOR SPflCE -28Of INCREflSE 
 
 B" - 4 FOR SflME OUTPUT QUflLlTy- REJECTIONS REDUCED FROM 10% TO I % 
 
 iMH^M i^^HH 1 
 
 r ur\ nrn-c. o ~T r wrv w ii ii* ** 
 
 _ DDDD 
 
 EQUIVflLENT MEflRTH flREfl,- FLOOR SPflCE 
 flND RELflTIVE WflLL THICKNESS 
 
 CMEMICflL OXlDflTION OF METflLLIC POWDER 
 
 OUTPUT PER MflN-6>5O"fo INCREflSE 
 
 OUTPUT PER UNIT OF FLOOR SPflCE -II 10 "f INCREflSE 
 
 I ^Ml 
 
 OUTPUT PER UNIT OF FUEL -<^0 fo INCREflSE WITH 
 FMRNftCE "fl" OVER FURNflCES "B" 
 
 -OXIOflT I ON INCREftSED FROM &O% TO 
 
 Fig. 5 
 
 11 
 

 
 Selection of Furnaces 
 
 HE selection of industrial heating equipment, 
 which must be coincident with the selection of a. 
 suitable form of heat energy (combustible or elec- 
 tric), resolves itself into the problem of determin- 
 ing the type, design, size, number and arrange- 
 ment of furnaces and auxiliary equipment necessary 
 to meet specific plant conditions, and of providing the most 
 efficient methods of heating, cooling, routing and handling the 
 material. 
 
 The physical or chemical nature of the heat-treatment 
 process; the requirements of quality; rate and quantity of 
 production; plant conditions and cost of operation are 
 basic factors which influence selection. There are many 
 other factors of varying importance, outlined by the chart on 
 page 13, any one of which may also influence the selection 
 and arrangement of equipment or the cost of production. 
 
 Uniformity of heating and cooling, and the relationship 
 of temperature, atmosphere, rate and time of heating and cooling 
 to the surface exposure and mass of product, are governed by 
 natural laws which cannot be ignored without sacrifice in quality 
 or quantity of product or economy of operation. 
 
 Selection is largely a matter of compromise in reconciling 
 requirements of quality with others related to methods of heating 
 and handling, output, plant conditions and cost of production. 
 
 Standardization of furnaces as to type, design and size, 
 to the extent common with boilers, engines, motors, machine 
 tools, etc., is impracticable because of the endless variety of 
 individual requirements. Such requirements usually involve 
 differences in size, shape, weight or composition of materials; 
 quantity and rate of flow; processes; methods of heating, cooling, 
 routing and handling of material; arrangement of equipment; 
 floor space; hours of operation; forms of fuel available; etc. 
 To meet such conditions there must be corresponding 
 variety in design and size of furnaces. 
 
 There is no more reason to assume that one form of fuel, 
 electricity, or furnace may be adapted to all industrial heating 
 requirements, than to assume that one type of dwelling or factory 
 would meet all building requirements, or that one form of prime 
 mover would meet all requirements for power. 
 
 The difficulty of definitely measuring heating results, 
 unlike measuring results in power, illumination or transportation, 
 adds to the complication because appraisement of furnace 
 performance must be based on quality and cost of prod- 
 uct and the method of operation under specific plant 
 conditions. 
 
 Temperature control, price or quantity of fuel, composition 
 of gases, etc., are merely contributing factors, and bear about the 
 same relation to industrial heating as they bear to the operation 
 of a motor truck. 
 
 The "heat unit" (B. t. u.) standard for judging fuel 
 values and " heat balance " for testing furnace performance 
 are incomplete and misleading, except for comparing fuels 
 of the same physical and chemical characteristics, and furnaces 
 of the same mechanical characteristics, operated under identical 
 conditions of applying and utilizing heat and of loading and 
 handling material. The "heat unit value" of a fuel, like the 
 "heat balance" of a furnace, is but one indication of economic 
 value. 
 
 It is misleading to compare coal, oil, gas or electricity 
 without considering their form characteristics and the 
 differences in the mechanical form and operation of the 
 furnaces or other appliances adapted to their use. Like- 
 wise, it is misleading to compare fuels of the same physical form, 
 
 such as clean producer gas, water gas, city gas, natural gas, 
 acetylene gas, etc., without considering differences in chemical 
 composition, combustible mixture, products of combustion and 
 calorific intensity of heat release. Consideration must be 
 given to the influence of furnace design and operation 
 upon the temperature and atmosphere, and upon the 
 uniformity and cost of product. 
 
 Electricity must be considered with regard to its "form 
 value" in determining its field of usefulness. A difference 
 in current (alternating or direct), or in voltage, phase or cycle; 
 the difference between arc, resistance and induction methods of 
 releasing heat, and the effect upon the product of differences in 
 the atmosphere set up in releasing the heat, must be considered in 
 relation to individual requirements. 
 
 The common practice of comparing inefficient furnaces, 
 
 unsuited to the specific manufacturing conditions and improperly 
 operated, with furnaces of a suitable type, more efficiently 
 operated, using another form of fuel, and crediting the improved 
 results to the difference in form of fuel or heat energy, is largely 
 responsible for mistakes in the selection of both furnaces and 
 fuels. 
 
 The "form value" of fuel or heat energy must be con- 
 sidered with the design and operation of the furnace. 
 
 Very often a fuel requires a particular type of furnace to enable it 
 to do certain work. Producer gas, for instance, is unsuited for 
 melting steel except in a regenerative furnace. Electricity with 
 the resistance method of releasing heat may be used to accomplish 
 a result not possible with the arc method, or vice versa. 
 
 It is unreasonable to compare an intermittently operated or 
 "batch type" regenerative furnace with a furnace of the con- 
 tinuous non-regenerative type, or to compare continuous furnaces 
 of different types, or single-chamber with multi-chamber furnaces, 
 even though the "heat balance" be identical, unless each affords 
 equally efficient means for applying the heat and handling the 
 product. 
 
 A difference in method of applying heat or handling 
 material may result in a difference in quality or cost of 
 product that would not be disclosed by consideration solely of 
 heat balance, fuel consumption, analysis of flue gases or indica- 
 tion of chamber temperature control. 
 
 No one type of furnace or form of heat energy (com- 
 bustible or electric) has a monopoly on uniformity of 
 heating or economy of operation. 
 
 Furnaces and fuels should be selected for the useful service 
 they can render when properly employed under specific condi- 
 tions, and with due regard to their form as well as price. Each 
 should be selected on its merits, judged by the factors outlined in 
 the chart. Their use is but a means to an end, the economic 
 value of which is measured by the resulting quality and cost 
 of the finished product or service, and not by any one phase 
 of their performance. 
 
 The variety in furnace design is illustrated by the accom- 
 panying diagrams of Rockwell furnaces, which have been developed 
 during many years of practice in different branches of industry. 
 Virtually all of the furnaces illustrated, each of which has its 
 field of usefulness as well as its limitations, have been built in 
 different sizes with varying methods of heat application, arrange- 
 ment of chambers, working openings, etc., for the use of different 
 fuels and electricity, to meet a wide range of heating processes, 
 manufacturing requirements and plant conditions. They 
 illustrate the endless variety of methods of applying in practice 
 the principles that govern the production of heat-treated prod- 
 ucts, and the necessity for considering each case on its merits 
 and in light of the development resulting from practice. 
 
 12 
 
II 
 
 15 ui 
 2"-" 
 
 
 z 
 
 S 2 
 
 1- <1 ^ 
 
 II 
 
 < 
 
 z^o:< 
 
 
 o 
 
 o st; 
 
 zS! 
 
 * 
 
 =3l5ii 
 
 t-0: |/)XUI 
 
 5 * SE 
 
 SzSS 2 
 
 Z L 
 bl 3 
 . 
 
 w fi u 
 
 
 "< ,1 
 
 -- 
 
 x-oo^l 2| 
 o-oXoal 2 T ? 
 
 a: a: ^- 
 
 * X 2 l 
 
 
 - Sfe 
 
 o: ui * 3 
 ui -i X 
 
 
 
 1 O L r J 
 
 t^go J 
 r-i oo2z r 1 -! 
 
 lilf ss< ! 
 
 i- u. < o 1*0 
 
 > m i| 
 o: < M 
 
 <?>- JL 
 
 
 S 
 
 UjZ 1 OJH- (OUI ' 
 
 O Z ^ 1 1 *~ Ul 
 
 ... ^^ *- . 1 II. 
 
 < tj " 5 
 
 Z V 3 O Q. 
 
 .. u. t- a. o in 
 
 1 
 
 !2f-o o 
 
 J , O *. 
 
 v n 
 
 ce ui ' 
 
 i>S2 
 
 iuiui t* u (- 
 
 
 lil 
 
 OU>Q 
 
 o: ui z 
 
 < (r. - 
 
 CEOP P 
 < . 
 
 -S IP 
 
 < l__l 
 
 *- 5 X 
 
 < ui ui o fJ-i o 
 
 
 i i 
 
 > 
 
 lsl| l| 11*11 5 
 
 S-M AUTOMATIC J^g 
 H PUSH 
 
 T-l LSEMI-AUTOMATIC-! GRAV 
 
 L SPEC 
 
 VTION Tft _T MATERIAL T0 BE H 
 .ATION TO LRATE OF PRODUC 
 FLE 
 -MUFFLE DcurDDroiTnov 
 
 " LCUPOLA 
 
 (POSITION pHEATING 
 TABILITY COOLING 
 
 'OROSITY LUNDER LOAD 
 
 HAMBER-ij-SINGLE END 
 HAMBER-TT- DOUBLE END 
 
 DTH 
 
 :IGHT 
 
 TION TO OPERATINt; FLOOR LEV 
 {ARC 1 
 RESISTANCE pVOLTS 
 CONVECTION^ l-AMPERES p 
 RADIATION ' 
 >rT 1 
 
 -^?I r v? * si 
 
 o <s i n P uis xo 
 
 e 5s g| iljalllf 
 
 3 zo N2 fe- -uninx LJ 
 
 t i Hi &is Is V ?L 
 
 t * </) < K- S JL ttU 
 
 ui ^^ '"u 5- O -i PI J3 
 Safe 5u !23ui<oui <u, 
 
 "^ Oztt!2| I xo V LJ 
 
 ^>o yS^fz *T J^ T 
 
 o*-C l _ii <z 2 
 r5 oo i ui ui 1 -!! 
 
 = S -- Big 8 Z 5 g|s 
 
 35x 52 gfla id til 
 
 Hurt eg! 
 
 *; M fi M?, 
 
 po^a S xil ?i < " 
 o a a Q o in a. < ^<n"S 
 
 jiiLJ YV i j : 
 
 ti O<z- . ui z 
 
 l.io i 1 i z PS 
 ftg-.o J- a 3 S 5 s M -3 
 ^pgu- 3 > 2 5 
 PC WE > J z u< " "Sui 
 
 z<|<2 83 1 z | o-jg- 
 
 TURNING. TILTING "-DRAWINC 
 STIRRING. ETC. 
 i. ETC. 
 ILVES. DAMPERS. ETC. 
 RS. TRANSFORMERS. SWITCHES. 1 
 
 
 f-MOTORS. BLOWERS. PUMPS BC 
 TANKS. BINS. GAS HOLDERS. 
 GENERATORS. TRANSFORMERS. 
 GAS PRODUCING EQUIPMENT 
 
 I Ji!S* 
 
 o= O"Q "Y *X 
 
 < <UIQ u. ce 
 _i c IIT i r; ui 
 
 *u.< d 5; iSj? 
 
 ,-0035 au!58 ,0*2" 5S?5=!Z >2 
 
 
 
 O o: ^u 
 
 ji; -SoziS ui i l 1 
 
 Ul 2 
 
 
 U. Z X - O Z ^ 
 
 < u a: _i | t-oO-iQ*- ^ 
 
 ;^ *-7i .^ 
 
 
 
 3 l Xin 
 
 1 Ir-Lh 
 
 z ui a: 
 t- I uj 
 
 V Z *xE 
 
 bd SS25 
 rn ^I 
 
 s-lH- 1 
 
 I3z r 1 ! 
 
 - P j 1 a. u. 
 
 O (K w <z j j_ i__l 
 
 J t%t Z3 
 
 .ot S* 
 
 es^z V * 
 
 uiit=ui ui y 
 
 a: o u>Q ' m t- 
 
 -T- 1 3 ssg 
 
 I 5 zwa. 
 
 I 2 H- 
 
 S o "> 
 
 Ul . 
 
 S u "r 1 zx 
 g g P-U U 
 
 2 3 5 [|1 T 
 
 x c iiioi 1 
 
 j Ul Ul S 3 UI Ul 
 
 rf So'lsiS g 
 
 in o < ui Q. _i o < 
 J 1 r 1 1 . 1 i 
 
 TT^ 
 
 = u. t P "o* 
 
 z^o < < ,< 
 
 O< z i Xi i-t-ui 
 
 E^ T , U T S^ u 
 
 in uiin <DQ z 
 O iui zoo: 
 0.1-Q 00:3 
 
 y Y-r 
 
 i- i- 
 * < i 
 
 U bl j 
 XX 3 
 
 Si X \~^ S l!sGs5S;is|s 
 52 a JL i ai s lt5s;i2 
 V..i M ! Cf 111 ?!*!??!. 
 
 ill s*5 liTiTfir 
 
 y g< "5s ti E ! i 1 5 g 
 
 5i 505 <o _i * z 
 
 a zz= w u oo . 
 
 -l 1 l 1 H K i ~ O 
 
 
 
 :OOLING SYSTEM 
 
 <*5 S < a. 
 
 O ui z Si > 
 
 5 o | 
 
 S t fi 
 
 P 
 
 u 
 
 111 
 
 uJ 5 
 
 u. u. u. 
 O O 1 
 
 r-J ^~^ , ' J __ 
 
 u * i 
 V "-I- 1 
 
 1 I 
 
 i T i 
 
 T ^ Ul 
 
 1 z a. 
 
 a 
 
 2 I U. Z Z 
 
 ( | U 
 
 HI 
 
 r s i B t 
 
 u y z s 
 
 
 _J * 2 2 
 
 o 5 
 
 i" : 
 
 ii 5 
 
 O z l- t- l 
 
 rn z g 2 o 
 
 J Li 
 
 Ml 
 
 U 
 
 luS 
 
 OO" 
 
 J I 
 
 _l Z 
 
 u 
 
 " I 
 
 ^ 
 
 
 z 
 
 i' . ? 
 
 s! 5x!j 
 
 pBSoi 
 
 
 LJ ^" 
 
 >: x w 
 
 
 
 it ^ 
 
 S 
 
 
 
 Z Ul 
 E Q. 
 3 O 
 
 03 < 
 
 (t O ft- 
 
 w 
 
 il 2 
 
 a: j 
 < 5 
 *" S V 
 
 2 88s 
 
 3 S ( 
 
 X o z ^S 
 
 Z 2 
 
 " *~ z 
 
 rl, l2 < <2 I 
 ' ' in rj ui ui y) i 
 
 S z S "^z?- 
 z . S <nnW jj o z<y 
 
 2 <"* ESSS 2 oz^z 
 5 ^3- oi u x "" "" *<ui< w 
 too ^"-"f o oz oSi SS 1 5 /?5] /v 
 
 O < l 1 
 
 OO<^ cc u uiui 
 
 < 3 UI | ( 
 
 ; s s^ < s: Aix**"^^ 
 
 O Ul 
 
 5-h--O-iS Z 
 
 ^a:,. ty, tp 
 
 n o J z < -o 1 />? i S('k 
 
 < x 
 u. ,_ u ui_i 
 
 S iesi 
 2 2^ Y- 
 
 E L_i*-3si3i,ix5 
 
 in 1 =zoou.^3m Q 
 O O Q i | ^ u> in ui 
 
 u. "-in 01 z " 
 
 *z| (n 2o8i ^ 
 o: O<x t_ uj ZI->Q a. 
 
 o ^< * .i 5 < 5o 
 
 it jf ff 
 
 Q Q 5 Ul i 
 
 1 Ul Ul N 5 
 
 <n i- ;r 5 
 r^ < <? 
 
 5 _i -J zol t-ea ce. ui 
 
 JlJTi ,V |<S2i|^ |g r 
 
 1 g^ii <3 z ui-io>uiin Oo 
 
 1 oi 1 
 
 Z Z U.Z .? 
 
 oo oo - 
 
 *Xx * V 
 
 < < :30 lu,- 1l? 
 
 * [^ <^z< ^x go: 
 
 nr (_ 
 
 
 3 Ul U. 
 
 OL o o 0:0: 2r> '-H 
 
 ,uiu alilS >ui 5,1 ui 
 
 ri ^ 
 
 < < a: t- 
 
 * T 1 IT 
 
 x 35 x uiui o_ 
 
 *~ 3 ' n L xi r: z 4 
 
 
 
 - - ._ 
 
 
 < <a >-9 ' 1 ' 0.0 S S 
 
 tnui ui o 1 3 
 
 ui - -< 
 
 51 Si 
 
 Unl* - 
 
 To o 1 
 
 si o VtS LS 
 
 1 " lil ill 
 
 ^ j ^ _i jn Q | - ^ 
 
 T<2 t-y zo:_ u, 
 <n z 1 C3 u 
 Vg' 2x u |* x^ 
 
 - P Lj5 z^2 I " ^ I i 1" a: 
 
 i | . o. o 
 H-i -^ " 2 
 
 z i <_i 
 
 Ul - ZO. Z W 
 !tj V>, Z Z 
 
 njSps 
 
 "uJ fig] 
 
 z i^ X V Lfi^lj 
 
 ^ 1^ o^^l ol V 2 ? 
 
 < > 3 _ U l l 3 O 1 CO Q- o Ul 
 
 2 zxzH^o 5_i 1 i i 
 OQz*in,Cl>! Q "o 3 E ^5 
 
 t -l i_iO 30 
 -uiiz...ul 00 
 Ij * Ul g DC ,-LJ 
 
 o5"d<J 1 
 
 2 *23ft?l 
 
 ui tt^vswiio* 
 t >- ^ z ' i 
 
 l ~^~~ l 5 " 12 
 
 O < ui u^ 
 
 
 z = Oiy J p 2 
 
 !u-5oo-oS <J5jJ 1 o a^B ~* 
 
 Z 5 5<H " 
 
 y> j Z ^ 1 j 
 
 f\n O^lS 
 
 P S LL ' ' "> O 1- 
 1 1 . > O3 < 
 
 V fe i x o 
 
 n9 3<3o> r- ' i 1 l z^9< 
 
 - E <5 ' i ' ^ 
 
 ?_." z 55j- 8 
 
 i I^f 
 
 < S z 
 
 ui l- O 
 
 O O t- lil 
 
 o **"* o 
 t i I o ^ u^ 
 
 z <E ce t- O 
 = O O ui - 
 
 ss; z cxcfain nn t^f^s^s s 
 
 sii i v^ 1 TI^Y s z 
 
 ,zz s^^gg si^si^i 
 
 uj 1 u_ (/> " O V O 9 
 
 gfiiy 
 
 Hi i 
 
 r-L-i. 8 " 
 
 U. U. Ul j_ 
 
 ol 3 3 ui : 
 
 o z ^ tg u o z i o z 
 
 S o S S: 8 ^5 z l| i S 
 
 t^gogdS z5t; 
 
 2 o 
 
 i ui O 
 
 V Y 
 
 i < "* ""* 
 
 o o 5 5 
 
 Z z 
 
 e JT7H | Q.L s g o ; 
 
 p g wC i^o 35c!x3< x = 
 1 iSll Sls 8 V V , 
 
 3 < LJ Ul I 
 
 e x z <A 
 
 L 
 
 n 
 
 L 
 
 1 
 
 jf 
 
 13 
 
HEATING FURNACES 
 
 LIGHT AND HEAVY FORGING - WELDING - TUBE BRAZING - RIVET. PLATE. ANGLE AND BILLET HEATING - 
 
 CONTINUOUS SLUG. BILLET AND ROD HEATING 
 
 u 
 
 2 - FB 3 - FC 4 - FD 5 - FE 
 
 6 - FF 7 - fG 6 - FH 9 - FJ ' 10 - FK 
 
 17 - FR - 18 - FS 
 
 - 21 - FV 22- FW 23- FX 24- FY 25- FZ 26- HA 
 
 Fig. 7 
 
 14 
 
ANNEALING AND HEAT-TREATING FURNACES 
 
 HARDENING - TEMPERING - CARBON.ZING - SHEET. ROD. W.RE AND TUBE MILL ANNEALING 
 
 SPRING FITTING - HIGH SPEED STEEL HARDENING 
 
 Fi 
 
 15 
 
ANNEALING AND HEAT-TREATING FURNACES 
 
 SHEET, ROD. WIRE AND TUBE MILL ANNEALING - CIRCULAR SAW AND PLATE HARDENING WITH 
 
 PREHEATING CHAMBER PUSHER. PAN PULLER AND CONTINUOUS LIVE ROLL ANNEALING 
 
 AND HEAT-TREATING - PACK ANNEALING IN TUBES WITH CHARGING TRUCK 
 
 
 73 
 
 7J!.j;aaaaie 
 
 D 
 
 / /n* Q p ^ r\ 
 
 / L 
 
 f * y 
 
 
 
 yy/ ///////// // // // ///////</// 
 ^\\ -iiii iHi-1T^F^Fii^^r^r^F : ~in^Fiir~ii, 
 
 
 a a a 
 
 Fig. 9 
 
 16 
 
CAR-AND-BALL AND CAR TYPE FURNACES 
 
 DRY.NG - BAK.NG - BLU.NG - JAPANN.NG _ CORE QVENS . HEAT . TREAT)NG 
 
 LARGE .RREGULAR FORG.NGS AND CAST,NGS - MISCELLANEOUS MATER.AL 
 PACKED IN POTS OR BOXES FOR BRIGHT ANNEALING. ETC. 
 
 J 
 
 adL 
 
 /M^; 
 
 1 -CA 
 
 / 
 
 3 
 
 
 / ////////////,- 
 
 4-CO 
 
 2! 
 
 I 
 
 Fi?. 10 
 
 17 
 
CONTINUOUS ANNEALING AND HEAT-TREATING FURNACES 
 
 &MlurTO 
 
 PUSHER TYPES FOR ANNEALING SMALL PARTS IN PANS. WITH COOLING TABLE. MECHANICAL DUMP INTO 
 
 PICKLING MACHINE OR TRUCK. WITH CONVEYOR RETURN OF PANS TO CHARGING END - CONVEYOR 
 
 AND PUSHER TYPES FOR A SEQUENCE OF HEATING AND COOLING OPERATIONS 
 
 Fig. 11 
 
 18 
 
AUTOMATIC CONVEYOR FURNACES 
 
 CARRY-THROUGH. .NS.DE DISCHARGE AND SIDE TAKE-OUT TYPES FOR DRY.NG. ANNEAL.NG. HARDENING AND 
 TEMPERING - ALSO FOR VERTICAL AND HORIZONTAL END HEATING AND FOR STR.P ANNEALING 
 
 I 
 
 AV V\ \VA\ AY VYAVAVAVA 
 
 
 
 ffi 
 
 Fig. 1 
 
 19 
 
MUFFLE, RETORT AND POT FURNACES 
 
 DIRECT-FIRED AND MUFFLE TYPES FOR ENAMELING, CUPELLING. RETORT ANNEALING AND HEAT-TREATING 
 
 AIR AND GAS HEATING - GALVANIZING AND TINNING - CYANIDE, LEAD. SALT AND OIL BATHS - SOFT 
 
 METAL MELTING - MISCELLANEOUS CHEMICAL, LIQUID BOILING AND SIMILAR OPERATIONS 
 
 tO-EK 
 
 Fig. 13 
 
 20 
 
CONTINUOUS ANNEALING AND HEAT-TREATING FURNACES 
 
 BRIGHT ANNEALING FOR COPPER - OIL AND LEAD TEMPERING - WIRE PATENTING - TINNING FOR 
 STRIP. WIRE AND SHEET - HARDENING AND TEMPERING IN SEQUENCE - 
 OPEN FLAME AND PLATE TYPE CLOTH SINGEING 
 
 \ 
 
 Fig 
 
 21 
 
ANNEALING, HEAT-TREATING AND PROCESSING FURNACES 
 
 DRYING - PLATE AND SAW TEMPERING IN SHAPE-RETAINING DIES - ROTATING HEARTH TYPES, WITH MANUAL 3 
 
 OR AUTOMATIC SIDE OR CENTER DISCHARGE - ROTARY CARBONIZING - REVOLVING DRUM, SCREW 
 
 CONVEYOR AND RABBLING TYPES FOR PROCESSING - REMOVABLE ROOF TYPE FOR 
 
 ANNEALING, HARDENING, TEMPERING AND SHRINKING - LIVE ROLL TIRE HEATING 
 
 Fig. 15 
 
 22 
 
ROTARY CYLINDRICAL FURNACES 
 
 INTERNALLY AND EXTERNALLY FIRED TYPES FOR ANNEALING AND HEAT-TREATING BOLTS. RIVETS. FORCINGS 
 CUPS. HUBS AND OTHER MISCELLANEOUS MATERIAL - DRYING. OXIDIZING AND REDUCING 
 METALLIC AND MINERAL POWDERS - HEAT-TREATING OPERATIONS IN SEQUENCE 
 
 23 
 
AUTOMATIC HEAT-TREATING FURNACE ARRANGEMENTS 
 
 ROTARY CYLINDRICAL TYPE IN SERIES FOR A THREE-OPERATION HEAT-TREATMENT, WITH MECHANICAL TRANSFER - 
 
 CARRY-THROUGH AND INSIDE DISCHARGE WALKING BEAM TYPES FOR ANNEALING AND HEAT-TREATING - 
 
 FLOOR PLAN OF CONVEYOR FURNACES IN COMBINATION WITH FORMING MACHINE AND QUENCHING TANK 
 
 'V.'V .''/////// ////TV. 
 
 5 - BE 
 
 Fig. 17 
 
 24 
 
MELTING FURNACES 
 
 SCRAP RECLAIMING - VITREOUS ENAMEL MELTING - PRECIOUS AND NON-FERROUS METAL MELTING IN 
 STATIONARY AND TILTING CRUCIBLE AND REVERBERATORY TYPES 
 
 25 
 
Scope and Limitations of Regenerative Furnaces 
 
 HE regenerative furnace illustrates the neces- 
 sity of considering the suitability of type and 
 design of furnace and form of heat energy (com- 
 bustible or electric) and the relation of thermal 
 conditions incident to the generation or 
 utilization of heat in a furnace to other 
 
 equally essential factors that influence the quality and cost 
 
 of heat-treated products. 
 
 Like the thermally efficient gas or oil engine, the re- 
 generative furnace has its limitations as well as its field of 
 usefulness. It is an efficient type of furnace for releasing and 
 utilizing heat from fuel, and is particularly suitable for the use of 
 fuels, such as producer gas, which, by reason of chemical compo- 
 sition and low calorific intensity, are not suited to high temper- 
 ature heating requirements without regeneration. 
 
 The regenerative principle, by recovering a part of the sensible 
 heat carried out of the heating chamber by the spent gases, 
 and utilizing it to preheat the air or fuel, or both, permits a high 
 ruling temperature and results in economy of fuel. 
 
 The regenerative furnace should be considered when the tem- 
 perature and nature of the heating process, the size of the furnace, 
 the cycle of operation or the plant conditions will not permit of a 
 simpler or cheaper method of securing the result desired. 
 
 Regeneration, like recuperation, is really an indirect 
 method of utilizing or recovering heat, and at times is 
 limited to preheating the air alone, as certain fuels, such as natural 
 gas and other hydrocarbon gases, cannot be preheated to the^ 
 extent possible with producer gas. When the temperature 
 requirements and plant conditions permit the use of 
 furnaces with more direct methods of utilization or re- 
 covery, the regenerative principle is unnecessary. But 
 where a high temperature is required, as for heavy forging, 
 welding or melting operations, it is frequently necessary to 
 resort to regeneration in order to establish a sufficient tem- 
 perature differential, to increase the rate of heating, or to make 
 possible the attainment of the desired working tempera- 
 ture, regardless of the saving in fuel or cost of furnace. 
 
 Considerable time is required to raise the temperature in the 
 regenerative furnace from a comparatively cold condition to a 
 relatively high working temperature. This is objectionable 
 when the furnace is used only eight or ten hours per day, unless 
 the heat is maintained between shifts to balance radiation and 
 flue losses. Temperature requirements and the nature of the 
 heating process or of the fuel may, however, make this fornace 
 and practice desirable even under such intermittent operation. 
 The objection does not hold when the furnace is operated con- 
 tinually at working temperature and capacity in two or more 
 shifts. 
 
 Practically all regenerative furnaces are of the "batch" 
 type and, therefore, limited in ability to continually maintain the 
 chamber at full working capacity and at uniform temperature, 
 due to the "batch" method of charging and discharging. 
 
 The requirements of temperature, output and the nature of a 
 process, such as melting, may make this batch handling necessary. 
 
 In other operations not confined to the "batch" type furnace, 
 an increase in production requirements without a change in the 
 nature of the heating process may suggest a different type of 
 furnace, capable of showing equal fuel economy with added 
 advantages in the metrfod of applying and utilizing heat, handling 
 material, reduction in floor space, etc. 
 
 Regeneration should not be considered when the furnaces 
 required are comparatively small and scattered. The floor 
 space required for a regenerative furnace is relatively large, due 
 to the area of the regenerators, reversing valves, flues and 
 chimney, which frequently occupy a greater space than the 
 furnace itself. This, with the heavier foundations required, 
 must be considered with the production requirements, plant 
 conditions and the space available for the furnaces, machines and 
 operatives. 
 
 There is a limit in the size of a regenerative furnace* 
 below which it is impracticable to go, because the possible 
 economy in fuel is outweighed by other considerations related to 
 the cost of installation and operation. 
 
 The regenerative furnaces of Rockwell design illustrated on 
 page 27, all of which were built prior to 1900, compare favorably 
 with the best present-day practice. 
 
 From the standpoint of fuel economy, these furnaces were 
 entitled to consideration prior to 1900 just as they are today. 
 Conditions limited their use at that time just as conditions, of a 
 different nature, limit their use now. 
 
 The tendency to consider the regenerative or recupera- 
 tive furnace as a possible solution of the so-called "fuel 
 problem" should lead to consideration of conditions responsible 
 for the limited use of such furnaces in the past and the extent of 
 their use in the future. 
 
 The relative cheapness in the past and flexibility of such highly 
 concentrated fuels as natural gas and oil made it possible for 
 the manufacturer to conduct many of his heating operations 
 without regard to fuel conservation. As fuel was cheap and 
 apparently not worth saving, the regenerative furnace did not 
 often appeal to him. Production, rather than cost of fuel, was 
 the order of the day. This, with relatively low labor cost and 
 working conditions not now countenanced, have been responsible 
 for the lack of progress that should have followed as a matter of 
 course. 
 
 Changing conditions and the demand for better quality 
 and decreased cost, coupled with relatively higher prices for 
 material, fuel and labor, will compel an increasing apprecia- 
 tion of all the factors that control the selection and use of 
 furnaces and fuels for the production of heat-treated products. 
 
 The question is not merely one of building a furnace 
 properly, but of determining the proper type and Design of 
 furnace to be built, with due regard to its suitability to the 
 nature of the heating operation, the manufacturing requirements 
 and the plant conditions. This calls for a careful study of the 
 problem as a whole, in order that none of the essential factors 
 affecting the quality of product and the cost of production 
 in the plant may be overlooked in an abstract consideration of the 
 generation and utilization of heat in a furnace. 
 
 26 
 
REGENERATIVE FURNACES 
 
 FORGING - WELDING - ROLLING - 
 CRUCIBLE PIT MELTING 
 
 27 
 
Relation of Type and Arrangement of Equipment 
 
 to Cost of Production 
 
 NE of the prime necessities when selecting in- 
 dustrial heating equipment is to provide means 
 for such heat application to the material 
 as will produce the best quality of finished 
 product. It is 'equally necessary to provide 
 equipment of such nature, extent and arrange- 
 ment as will afford the best means for handling as well as 
 heating the material in order to produce the greatest quantity 
 at the lowest cost. And it is certainly advantageous to provide 
 means for the operatives to work efficiently and in 
 reasonable comfort. 
 
 All these considerations should contribute to the final result, 
 so that the required quality and quantity of finished product may 
 be secured with minimum labor, fuel, power, floor space, rejected 
 material and overhead charges. 
 
 The advantages of adapting industrial heating equip- 
 ment to the manufacturing requirements and plant con- 
 ditions in each individual case are not always appreciated. 
 Consideration only of strictly thermal features of the operation 
 is often responsible for failure to effect the economies which, 
 almost without exception, may be brought about by intelligent 
 selection, arrangement and operation of equipment 
 properly adapted to the individual plant conditions. 
 
 No two cases are alike. Two plants manufacturing the 
 same product in the same quantity may require different heating 
 equipment or different fuel, just as they may require different 
 building construction or different methods of handling the mate- 
 rial. Two separate departments of the same plant working on the 
 same material may require different equipment, fuel or methods 
 on account of different manufacturing requirements or other 
 influences such as location, floor space, relation of these to each 
 other, etc. 
 
 A different and better type of furnace, a different ar- 
 rangement of furnaces or other equipment, method of 
 handling, form of fuel or all together may so alter an 
 overcrowded, uncomfortable heating department that it 
 will turn out more and better product at less cost. 
 
 The furnace floor plans on page 29 (without reference to size 
 of furnace or manner of heating) illustrate different arrangements 
 of chambers and working openings, and suggest different types 
 and designs of furnaces and various methods of charging and 
 discharging in order to secure the greatest uniformity of product 
 and rate of production. 
 
 i 
 " 1-KA" may be a tool room forge with a chamber a few inches 
 
 wide or a plate heating furnace fifteen or twenty feet wide. 
 Or it may vary in length from a size required to heat a small tool 
 up to one suitable for a steel shaft a hundred feet long. It may 
 represent the chamber in a japanning oven maintaining heat at a 
 few hundred degrees or a furnace for forging steel. 
 
 "25-KZ" similarly may vary in chamber size and temperature, 
 with means for moving the material through the chamber con- 
 tinuously or intermittently, or for charging and discharging at 
 either or both ends. 
 
 Either of these may be built in double-chamber form (7-KG or 
 29-LD) with similar variations in size or temperature, and various 
 methods pf handling material and producing and applying heat. 
 
 Many such combinations may be provided to facilitate 
 the proper heating and handling of the material. Other 
 combinations may be warranted by the necessity for improve- 
 ment in working conditions, to employ the floor space to better 
 advantage, or to effect the general all-around economy that 
 frequently results from discarding comparatively small and in- 
 efficient furnaces in favor of the larger and heavier units. 
 
 The type, design, size and .number of furnaces, with reference to 
 the form and calorific intensity of the fuel or heat energy, and the 
 methods of handling and routing material must be determined 
 with reference to the methods of heat application, manufacturing 
 requirements and plant conditions. The furnace units should 
 be as few as possible to secure the desired output with 
 continuity of operation. Each should be properly designed 
 and proportioned so that it will contribute its share of properly 
 he'ated product with economy of fuel, labor and floor space. 
 
 A number of small furnaces should not be considered when 
 fewer larger units may be employed, because of the relative re- 
 duction in floor space, radiating surface, fuel consumption, time 
 and labor. 
 
 Manufacturing requirements for quality product at low 
 cost under conditions of quantity production frequently 
 suggest mechanical means for handling to such an extent 
 that the furnace is in reality an automatic heating 
 machine. 
 
 Such automatic methods represent ideal practice and should be 
 chosen wherever the conditions permit. The field of usefulness 
 of such automatic methods, however, is limited by the quantity 
 or rate of flow of the material to be heat-treated, and by varia- 
 tions in size, shape or composition of the individual pieces or 
 batches, and by other conditions that do not permit of strictly 
 continuous operation on a comparatively large scale. 
 
 To heat correctly is the first consideration. Whatever the 
 manner of heat application or method of handling material, it 
 must always be borne in mind that the fundamental factors 
 governing uniformity of heating or cooling cannot be 
 ignored without corresponding sacrifice in quality of product 
 and ultimate cost. 
 
 To heat economically it is necessary to consider the influence 
 of the type, design, size, number and arrangement of furnaces 
 on the items of labor, fuel, output, floor space, and investment, 
 and other items included in the actual cost of production. 
 
 28 
 
ARRANGEMENTS OF FURNACE CHAMBERS AND WORKING OPENINGS 
 
 SOME OF THE POSSIBLE ARRANGEMENTS OF FURNACE CHAMBERS AND WORKING OPEN.NGS 
 
 AVAILABLE FOR MEET.NG .NDIV.DUAL REQU.REMENTS AS TO MATERIAL TO BE HEATED. 
 
 CHARACTER OF OPERATION AND PLANT CONDITIONS 
 
 , 
 
 2ZZZZI 
 
 vV///// 
 
 / 
 
 t 
 
 / 
 
 / 
 
 'h 
 
 n 
 
 / 
 / 
 
 n r. 
 
 D n n 
 
 ///// 
 
 / 
 / 
 / 
 
 / 
 
 i2 d 
 
 / 
 
 / 
 
 > 
 / 
 
 / 
 
 // /// 
 
 i d 
 
 / 
 / 
 > 
 '-' 
 
 
 2 
 
 -\ n P^ 
 
 \ 
 
 l n ^ 
 
 7- 
 
 
 / 
 
 i n n d 
 
 . 
 
 /,-/.- /'V.'V.-V-V'V 
 
 b n n FV 
 
 6 
 
 - 
 
 UH 
 
 
 
 
 9 
 
 
 
 <j 
 
 
 
 
 10 
 
 - 
 
 KK 
 
 i3 r 
 
 / 
 
 3 r 
 
 -; 
 
 /i d 
 
 / 
 
 / 
 
 h F 
 
 / 
 
 
 / 
 
 1 E 
 
 / 
 
 a c 
 
 . 
 
 /_ 
 
 
 / 
 
 ^/ 
 
 . 
 
 bi r 
 
 
 2Z22Z 
 
 
 
 Y,'Y- 
 / 
 
 / 
 F/ 
 
 -r 3 h 
 
 / 
 
 / 
 
 / 
 
 7 
 V 
 
 /; 
 
 / 
 
 TIZS 
 
 1 
 
 u I 
 
 "TTJt, 
 
 - 
 ,/ 
 / 
 
 / 
 
 / 
 
 '/////, 
 
 / 
 / 
 
 / 
 T t r-; 
 
 '/////, 
 
 71 M 
 
 '/''///////////////// 
 
 
 / 
 / 
 
 / 
 / 
 
 / 
 
 ^ 
 
 '/v/y /////////// /////// 
 
 Li lj 
 
 i 
 
 
 /A \/ ///////////////// 
 
 /\ n n n n n 
 
 23- KX 
 
 T 
 
 xi 
 
 23 
 
 T3 E 
 
 J3. 
 
 TJ 
 
 n 
 
 .. ; ''.' '.'. . '.-i i [ 
 
 - r 
 
 - 
 
 u u 
 
 n n. 
 
 Fig. 20 
 
 29 
 
Relation of Price of Fuel to Cost of Production 
 
 HE relation of price of fuel to ultimate cost of 
 production in industrial heating is, in many 
 respects, similar to that prevailing under other 
 conditions involving the use of fuel or heat, such 
 as illumination or transportation. 
 
 The character and cost of the final result 
 are determined by a combination of apparatus, fuel and 
 operative, and not by any one or two of these factors. 
 
 The cost of fuel, which is based upon the price and quan- 
 tity consumed, is but one item in the ultimate cost of 
 production. The fuel consumption is governed by the 
 design of the furnace and the manner in which the heat is gener- 
 ated, applied and utilized. The average manufacturer does not 
 control the price of fuel, but to a great extent he can control the 
 cost of his heating operations by using furnaces and fuels 
 adapted to his manufacturing requirements and plant 
 conditions. 
 
 Too great emphasis is usually placed on the heat unit 
 (B. t. u.) cost of fuel and upon the details of combustion 
 and heat release ; and too little attention is given to the economy 
 attainable under better methods of heat application and utiliza- 
 tion possible with apparatus of improved design. 
 
 The practice of selecting fuel on the basis of "heat unit 
 cost, " or of selecting apparatus to use any one form of 
 fuel on the basis of " heat balance, " or "fuel consumption, " 
 without considering the mechanical form and suitability of the 
 apparatus, or the intelligence and skill of the operatives, is just 
 as illogical in industrial heating as in transportation. 
 
 Many absurd comparisons are made between different fuels 
 merely on their heat unit content, without regard to physical and 
 chemical form, which very largely determine their field of useful- 
 ness. 
 
 Price, on the basis of heat unit content, must be con- 
 sidered together with the form of fuel and apparatus, and 
 
 the suitability of both to the conditions. 
 
 The economic value due to "form" of fuel and equip- 
 ment, suggests consideration of "form value" in the selection 
 of fuels and furnaces or other apparatus dependent upon heat for 
 operation. 
 
 "Form value" is a term denoting the intangible value due 
 to physical condition or chemical association of a source of 
 heat energy (combustible, electrical or mechanical) and method 
 (apparatus and operation) of transformation into useful service. 
 It is not measured by the thermal (B. t. u.) value or the price 
 of fuel, nor the type, price or heat balance of a furnace. 
 
 Innumerable instances in the fields of power production, 
 transportation, and illumination indicate that "form value" is 
 of greater importance than thermal value in the selection of 
 fuel and apparatus. Otherwise no other form of heat energy 
 could compete with bituminous coal, and the chief elements of 
 progress in each field thus far attained would be nullified. 
 
 "Form value" is a factor of fundamental significance in 
 the problem of selecting fuels and furnaces or other 
 apparatus dependent upon heat for operation. Accordingly, 
 an adequate survey of the problem should include specific con- 
 sideration of the "form value," in addition to the "thermal 
 value, " price of fuel, " heat balance, " and cost of apparatus. 
 
 Such survey is necessary for an unbiased consideration of the 
 problem as a whole and a proper appraisal of the actual require- 
 ments. Individual conditions and the economic value of 
 the ultimate result must decide the conflicting claims of ad- 
 
 vocates of the arc, induction or resistance methods of heating by 
 electricity; combustion experts; those urging the merits of differ- 
 ent forms of gas generated in isolated or central station plants; 
 fuel oil or powdered coal enthusiasts; mechanical stoker adherents, 
 etc., or those interested in special forms of furnaces or other 
 apparatus without reference to the form of fuel or electricity 
 to be employed in connection with them. 
 
 The approximate relation of the heat energy in fuel to 
 the results accomplished by its use, and the possibilities for 
 improvement in application and utilization of such heat energy, 
 are illustrated by the diagrams on page 31, which are fairly 
 representative of present-day practice. 
 
 The indirect relation of the cost of fuel and the more 
 direct relation of the combination of equipment, fuel and 
 operative to the character and total cost of the service or prod- 
 uct is even more pronounced in industrial heating than in the more 
 highly developed field of power. 
 
 Inadequate appreciation of the great variety of manufacturing 
 conditions; the difficulty of definitely valuing the quality and 
 cost of finished product ; and the too frequent practice of apprais- 
 ing the operation by thermal standards only, lead to neglect of 
 the principles governing the production of heat-treated products 
 and the selection and operation of apparatus as a proper means 
 to that end. 
 
 It is apparent from practice that unless other conditions 
 are equal, the cost of fuel or so-called "thermal efficiency" 
 of the apparatus are not the determinative factors. 
 
 The common hot-air engine extensively used in isolated country 
 districts for pumping water, and for other operations requiring a 
 small amount of power, is relatively inefficient in utilizing fuel 
 energy compared with the Diesel or other internal combustion 
 engines. Under certain conditions, however, it has some operat- 
 ing advantages in permitting the use of comparatively cheap fuel 
 and requiring minimum attention, the economic value of which 
 more than offset the loss in fuel. 
 
 The simply constructed and operated foundry cupola for 
 melting grey iron is generally considered an example of thermal 
 inefficiency compared with the modern regenerative open hearth 
 furnace for melting steel. Although the two should not be 
 compared on the basis of "heat balance," because of the differ- 
 ence in construction, operation and purpose, it is interesting to 
 note that the cupola is the more efficient of the two in heat appli- 
 cation to the product and in utilization of heat. If 
 it were operated continuously and the waste heat utilized as in 
 blast furnace practice, the comparison would be even more 
 striking. 
 
 Similar comparisons, illustrating the economic value due to 
 form of apparatus or heat energy regardless of "thermal 
 efficiency," represented by the "heat balance," may be made 
 between steam, electric or gasoline-driven cars moving on rails 
 and automobile trucks or passenger automobiles moving on 
 roads ; and internal combustion engines of two or four cycles with 
 1, 2, 4, 6, 8, 12 or more cylinders to meet the varying requirements 
 of automobiles, watercraft, aircraft, or small isolated power 
 plants. 
 
 While the heat unit standard is a gauge of the thermal 
 value of fuel, it is not a real gauge of its economic value, 
 nor is the " hea( balance" a real gauge of the economic 
 value of apparatus. 
 
 Each form of fuel, electricity and appliance has its field of 
 usefulness as well as its limitations. Proper selection of equip- 
 meiflt and fuel to suit conditions necessitates consideration of all 
 factors governing the accomplishment of a specific result. 
 
 30 
 
D-25 
 2521 
 
 ECONOMIC VALUE OF BY-PRODUCTS. POSSIBLE HEAT RECOVERY AND 
 THE EFFECT OF OPERATING CONDITIONS NOT CONSIDERED 
 
 BLUE: WHTER Gfl5 (COLD COKE) 
 
 10% STEflM 
 
 1.57. fl5H-rrc. 
 
 BLOW-UP QflS 
 
 SS.5% SENSIBLE HEflT 
 BLUE WflTER Qfl5 
 
 REVERBERATORS flIR FURNflCE 
 
 RICHflRDS 
 
 .< e ]. WflSTE 
 RflDlflTlON-ETC. 
 
 FOUNDRY CUPOLfl 
 
 RICHflRDS 
 
 50% WflSTE Qfl3-ETC. 
 
 18% RflDlflTION-ETC. 
 
 HOT flIR ENGINE 
 
 TRflOC CflTflLOQ 
 
 CONVERSION L055 
 
 1.5 fo PUMP LOSS 
 
 1.57. IN WflTER PUMPED 
 
 OIL PRODUCER 
 
 TEST RCPOBT 
 
 6% RflDlflTlON flND 
 CONDUCTION 
 
 f. PILOT FLflME 
 37. SENSIBLE MEflT 
 
 15%, RESlDUflLS 
 '-727. OIL PRODUCER Gfl5 
 
 BLflST FURNflCE 
 
 fl.l & 51., MODIFIED - 
 
 5TOVE5 
 % POWER 
 25% SURPLUS QflS 
 52% IN FURNflCE 
 
 10% EVAPORATION -ETC. 
 i 
 
 / / / / 7~A 14% SLflQ 
 
 % REDUCTION 
 MOLTEN IRON 
 
 GflSOLENE flUTOMOBILE: 
 
 13% FRICTION 
 387. COOLING 
 
 31% TO 43% EXhflUST 
 
 -*fl*- t>7. TO 107. flT ENGINE SMflTT 
 
 .5 7 TO fo% ROflO L035 
 1.57. TO 47. USEFUL POWER 
 
 Qfl5 ENQINE 
 
 Or MINES. MODiriEO- 
 
 35% EXHFW5T 
 
 PRODUCER Gfl5 (BITUMINOUS COflL) 
 
 -w.-5.-M., 
 
 7% FRICTION fiND RflDMTION 
 
 25% flT ENGINE 5MflFT 
 31 
 
 157. SENSIBLE KflT 
 COLD PRODUCER Gfl3 
 
 OPEN-HCflRTh FURNflCE 
 
 - RICM(WD5, 
 
 7% 
 
 REQENERflTOR L055 
 
 3% 
 
 21% CHIMNO 
 
 MOLTEN 3TEEL 
 
 STEflM LOCOMOTIVE 
 
 fl SM.E 
 
 40% BOILER LOSS 
 
 201. 
 
 'S////A wt 
 
 ZZJ 10% TO 12% FRICTION 
 47. TO fe7. flT DRflWSflR 
 
 DIESEL ENGINE 
 
 \ZZ2 l<7 FRICTION flND PVMP3 
 
Factors Governing Selection of Fuel or Electricity 
 
 HE selection of fuel for industrial heating 
 
 should be based upon appreciation of the radical 
 difference between the price of fuel, on the one 
 hand, and the quality and cost of product result- 
 ing from the generation, application and utilization 
 of heat, on the jother. 
 
 The result sought from the application of heat is pro- 
 duced not by fuel or heat alone, but by a combination of 
 equipment, fuel and operative. These elements should be 
 selected with regard to their suitability to the conditions govern- 
 ing the conduct of the operation as a whole, and to their ability 
 to produce the desired result at a reasonable cost. 
 
 In industrial heating, as in transportation and illumination, 
 a complex field must be surveyed before a proper selection of 
 fuel and equipment can be made. The nature of the heating 
 process, the type and size of furnaces adapted to the 
 manufacturing requirements, the plant conditions, the 
 personnel, and price of available fuels or electrical energy 
 are the controlling factors. Each of these must be considered 
 together with other essentials outlined by the chart on page 33, 
 any one of which may influence the final choice. 
 
 The practice of selecting fuel on the basis of thermal 
 value and price is both inaccurate and misleading unless 
 at the same time proper consideration is given to other essentials 
 which largely determine the suitability of fuel and equipment 
 regardless of price or thermal value. Otherwise, no other form 
 of fuel could compete with bituminous coal burned in the open 
 grate or blacksmith fire. 
 
 The price of fuel may influence but it certainly does 
 not determine the cost of finished product. Price must 
 be considered with the amount consumed and the suitability 
 of the "form value," both of fuel and equipment, to the nature 
 of the heating operation as a whole. 
 
 The form of equipment must be considered with ref- 
 erence to the manner of applying and utilizing the heat, 
 and of handling the material to be heat-treated, because 
 these essentials are as directly linked to the quality and cost 
 of finished product as are the price of fuel or method of generating 
 heat, whether it be through combustion or the arc, induction 
 or resistance methods of releasing heat from electrical energy. 
 
 Whenever there is a difference in physical or chemical 
 form of fuel, or in mechanical form of equipment, there is 
 a difference in economic value regardless of comparative 
 thermal value or price. 
 
 Fuels of the same physical form may vary greatly in 
 chemical composition. A difference in ash, sulphur or 
 moisture content of coals, or in percentage of inerts, com- 
 bustibles, or combination of the same chemical elements in 
 different gases, may influence the choice regardless of price. 
 The difference between the arc, induction and resistance methods 
 of releasing heat may influence the choice of equipment and the 
 form of electricity, i. e., whether alternating or direct current, 
 and the voltage, phase or cycle. 
 
 It is as illogical to compare different forms of heat 
 energy with regard to a certain result, as it is to compare 
 electricity with any one form of fuel on the basis of thermal 
 value, unless proper consideration is given to the form 
 of equipment adapted to each. 
 
 In industrial heating, as in illumination or transporta- 
 tion, much of the advantage frequently credited to some 
 one form of energy is actually due to the appliance em- 
 ployed in connection with it. A different design of appli- 
 ance or method of operating may reverse conclusions based 
 on thermal value or price. 
 
 The relative cost of kerosene, city gas or electricity on the 
 heat unit basis is determined by the price per gallon, per thou- 
 sand cubic feet, or per kilowatt hour, respectively, but such 
 comparisons do not indicate their relative value as sources of 
 energy for illumination. The price and form of energy is usually 
 considered with the type of lamp, which largely determines the 
 nature and cost of the result. 
 
 Frequently the "form value" of a suitable combination 
 of equipment and fuel will prevail regardless of price. 
 
 This is illustrated by the practice of using comparatively ex- 
 pensive gas for intermittent cooking operations in the kitchen 
 in preference to comparatively cheap coal, which under different 
 service requirements is preferable for heating the house. The 
 advantages of incandescent electric lamps for the illumination 
 of the interior of a railway coach may be accompanied by the 
 use of oil lamps as signals at the end of the train. 
 
 Similar conditions in the field of industrial heating indi- 
 cate the necessity of considering, in addition to the apparent 
 value due to price of fuel, the "form value" due to physical 
 condition or chemical composition of the fuel or mechanical 
 characteristics of suitable equipment, in order to establish a 
 reasonable balance between the price of fuel and the nature 
 and cost of the heating operation. 
 
 The efficient utilization, in suitable furnaces, of the 
 right form of fuel or electricity, selected to meet definite 
 requirements of heating and handling, rather than the 
 price alone, must be depended upon to lower the cost and 
 improve the quality of heat-treated products. 
 
 The nature of the heating process, manufacturing require- 
 ments and plant conditions may in many instances make city 
 gas at $1 per thousand cubic feet economically preferable to oil 
 at one cent per gallon, or coal at $1 per ton. In other instances, 
 electricity at a very much higher price, based on equivalent 
 energy cost, is given the preference because of the operating 
 advantages made possible by a specific form of electric energy 
 and appliance. 
 
 A fuel such as bituminous coal may be attractive on the 
 basis of price but objectionable in form, or vice versa, as 
 in the case of gas or electricity. Gases of the same physical 
 form may vary greatly in chemical composition, which in itself 
 may limit the field of usefulness regardless of price. Suitable 
 furnace design may overcome these objections. Thus the 
 use of bituminous coal is made possible in enameling furnaces 
 by the use of a muffle, which might be unnecessary in electric 
 furnaces in which gases, if any, originating from the resistance 
 material did not affect the product to be heated. 
 
 The innumerable factors controlling the selection of fuel 
 and the generation, application and utilization of heat for 
 industrial or domestic purposes, denotes a field of useful- 
 ness, in suitable apparatus, for all varieties of solid, 
 liquid, gaseous and electrical fuel or heat energy. 
 
 Extension of the use of any one form of fuel or electricity 
 automatically follows the development of apparatus for con- 
 verting that form of energy into useful service in heat, power 
 or illumination. The apparent relative economic value of the 
 different forms on the basis of price, at the moment, may be 
 changed in the future, as it has been in the past, by the develop- 
 ment of better methods of heat application and more 
 efficient apparatus to make possible either a different 
 result or to accomplish the same result at less cost, by 
 decreasing the amount of energy required without any change 
 in the price. 
 
 32 
 
Itf IS I s v 
 
 u -< ow T> * 
 
 LJ I 3 B tJ LJ 5 1 
 
 V J I I 1 1 ,1 L 
 
 L 5 ; 
 
 
 
 1 
 
 
 i_i i a ssg ' 
 p=^ 52 i i i : 
 
 ; 
 
 33 
 
Comparative Prices of Fuel on B. T. U. Basis 
 
 HE chart on page 35 affords a ready means of 
 comparing fuels on the basis of their B. t. u. 
 cost by direct comparison of the price of one 
 fuel with the price of another; by comparison 
 of the relative qosts per million B. t. u., or, on 
 
 an assumed cost per million B. t. u., reading directly the 
 
 "permissible" prices for various fuels. 
 
 The horizontal lines represent prices for fuels; the 
 vertical lines, costs per million B. t. u. of heat energy; the 
 diagonal lines are the plotted heat unit values of fuels. 
 
 The chart is read by converting the price of a given fuel (hori- 
 zontal line), at its intersection with the diagonal line of the heat 
 unit value of the fuel in question, to the vertical intersecting 
 line which, read at the bottom of the chart, indicates the cost 
 per million B. t. u., or vice versa. 
 
 To illustrate: For a comparison of 12,000 B. t. u. coal at 
 $5.00 per ton with fuel oil. Reading from the left scale, the 
 horizontal line from $5.00 per ton is followed to its intersection 
 with the diagonal value line for 12,000 B. t. u. coal, then verti- 
 cally down to the scale at the bottom of the chart, which in- 
 dicates a cost of approximately 21c per million B. t. u. The 
 same vertical line is followed to its intersection with the diagonal 
 value line for fuel oil, then horizontally to the scale on the right 
 of the chart, which indicates a price of approximately 3c per 
 gallon, at which such fuel oil would have to be procured to 
 equal on a heat unit cost basis 12,000 B. t. u. coal at $5.00 per 
 ton. 
 
 Reversing this process, if fuel oil should cost 8c per gallon, 
 this horizontal line carried to its intersection with the fuel oil 
 diagonal, then down to the bottom, indicates a cost of approxi- 
 mately 56c per million B. t. u. This same vertical line carried 
 to its intersection with the 12,000 B. t. u. coal diagonal, then 
 horizontally to the left, indicates a comparative price for coal 
 of $13.50 per ton. Direct comparisons are thus available be- 
 tween the coal and fuel oil prices; indicating that fuel oil would 
 have to be available at 3c per gallon to equal in heat unit cost 
 12,000 B. t. u. coal at $5.00 per ton; and that if fuel oil cost 8c 
 per gallon, 12,000 B. t. u. coal would be no higher in B. t. u. cost 
 at $13.50 per ton. 
 
 This method of comparison takes into account the cost 
 per million B. t. u. merely as an intermediate step. If 
 
 desired, fuel prices may be compared directly. For example, 
 following along the horizontal line of $5.00 per ton coal to its 
 intersection with the diagonal 12,000 B. t. u. coal value line, 
 then vertically down to the intersecting diagonal line for fuel 
 oil, then horizontally to the right, reading directly the com- 
 parative price of 3c per gallon for fuel oil. 
 
 At an assumed cost per million B. t. u., the "permissible" 
 prices for the various fuels to be considered will be found by 
 following the vertical "cost per million B. t. u. " line to its 
 intersection with each of the fuels in question, then to the right 
 or left respectively to read the "cents per gallon" for a liquid 
 fuel, the "dollars per ton" for a solid fuel, or the "cents per 
 thousand cubic feet" for a gaseous fuel. 
 
 In the cases of acetylene gas and electricity, the prices 
 are read to the left and right respectively of the chart as 
 cents per hundred cubic feet and per Kw.h. The ver- 
 tical intersecting lines, however, must be read at the 
 extreme bottom of the chart as dollars per million B. t. u. 
 and transposed accordingly for comparison with the other fuels 
 which are rated at cents per million B. t. u. 
 
 The chart "Industrial Fuels" on page 44 furnishes a direct 
 B. t. u. cost comparison of the ordinary industrial fuels based 
 on assumed prices which approximate the present-day market. 
 
 These charts have been prepared to facilitate a comparison 
 of the B. t. u. cost of fuels, but in making such comparisons it 
 must always be borne in mind that B. t. u. costs are but one 
 factor, and in most cases the minor factor, affecting the total 
 cost of any heating operation or the manufacture of any heat- 
 treated product. 
 
 If mass generation of heat is considered without refer- 
 ence to its nature or use, then the B. t. u. cost of fuel 
 would be the factor determining the choice. In prac- 
 tically all cases, however, the combustion of fuel the generation 
 of. heat is a preliminary to the application and utilization of 
 heat in the accomplishment of a required result, and in every 
 instance there must first be considered the suitability of a 
 fuel to the nature of the operation, equipment, and the 
 general operating conditions. 
 
 Much the same situation exists as in the case of foods, 
 
 which are frequently considered as a form of fuel. Certain 
 foods may be low priced in relation to their potential value in 
 calories, and yet not suitable for use under every condition. 
 Baked beans, for example, represent a low-priced food, and yet 
 for the convalescent requiring a large amount of nourishment, 
 such relatively high cost foods of different character as milk, 
 eggs, animal jellies, etc., may be given the preference. The 
 choice should be based not alone on the relative value in calories 
 of such foods, but with regard to their suitability to the indi- 
 vidual requirements. 
 
 The term "form value" is suggested to give expression to the 
 intangible value due to difference in physical characteristics and 
 chemical association that exists between the various fuels; 
 and it is the "form value" in addition to price of a fuel, 
 influenced, of course, by the design and method of operating 
 the equipment employed with it, that largely determines its 
 economic value and field of usefulness. 
 
 It is the advantages due to "form value" of electricity 
 with suitable appliances which, under certain conditions, 
 suggests its use for illumination when gas or oil might 
 be cheaper on a B. t. u. basis. Similar conditions may 
 suggest the use of gas with the modern gas range for cooking 
 in preference to coal, wood or oil at a lower B. t. u. price. Dif- 
 ferent conditions may warrant the choice of lower-priced fuels 
 which, with suitable apparatus, may meet the operating require- 
 ments at reasonable cost. 
 
 With fuel, as with food, the choice is determined not by 
 the relative heat unit cost, but by consideration of price 
 with "form value" of the fuel and equipment adapted 
 to it, and the suitability of the combination to definite 
 operating conditions. 
 
 A comparison of fuels on the basis of B. t. u. value is not 
 a test of economic value unless the fuels, so compared 
 have the same physical characteristics and chemical 
 association and are utilized in appliances having the same 
 mechanical characteristics and operated under the same 
 conditions. 
 
 Price of fuel is but one item in the cost of heating, 
 just as it is but one item in the cost of transportation or 
 illumination. Operating cost includes not only the price of 
 fuel, but also the quantity consumed, which is largely governed 
 by the manner of applying and utilizing the heat in useful 
 service. This in turn is greatly influenced by the design and 
 method of operating the appliance, whether it be a furnace or 
 a motor truck. 
 
 34 
 
CENTS PER GALLON OF LIQUID FUEL OR PER kw.ll. OF ELECTRICITY, 
 
 oo r-- co ira o- co cxi * c 
 
 DOLLARS PER TON (2000 Ib.) OF SOLID FUEL, 
 
 00 
 
 _gggsgss 
 
 CENTS PER 1000 cu.ll. OF GASEOUS FUELS OR PER 100 Ctl.ft, OF ACETYLENE GAS, 
 
 35 
 
Comparative Heating Value of Industrial Fuel Gases 
 
 HE relative value of gases for industrial or 
 domestic heating or power service is not defi- 
 nitely determined by the customary method 
 of comparison on the basis of heat units (B. 
 t. u.) per cubic foot. 
 
 It is a common belief that the suitability of 
 a gas as a source of heat or power is determined by its B. t. u. 
 value and price, and that gases higher in B. t. u. per cubic foot 
 are the more desirable; but this is far from true. 
 
 The heat unit content of a gas is not a true indication 
 of its heating value in an economic sense. In addition to 
 the B. t. u. value there must be considered the chemical com- 
 position of the gas and of the mixture of gas and air supplied 
 for combustion, and also the influence of the design of furnace 
 or other appliance employed for the generation, application 
 and utilization of the heat. 
 
 The chemical composition of a gas fixes the volume of 
 air required for combustion, and the mixture so formed, 
 from which the heat is released, has a B. t. u. value per 
 unit of volume much less than that of the original gas 
 itself. The quantity of air required for combustion of the 
 various gases fluctuates greatly, being more for the richer gases 
 and in general less with the decrease in B. t. u. value. 
 
 The heat unit value of the usual industrial gases may vary 
 from 100 to 1500 B. t. u. per cubic foot; the theoretical quantity 
 of air required for combustion may vary from one to twelve 
 cubic feet per cubic foot of gas; the B. t. u. value of the com- 
 bustible mixtures of these same gases, with the theoretical 
 quantity of air required for combustion, may vary from 50 to 
 115 B. t. u. per cubic foot, or less with an increase in the relative 
 quantity of air supplied. See chart page 37. 
 
 The B. t. u. value of a gas or its combustible mixture 
 does not indicate the temperature obtainable by com- 
 bustion or determine its field of usefulness. 
 
 Natural gas at 900 B. t. u., while apparently three times 
 as rich as water gas at 300 B. t. u. per cubic foot, has a lower 
 flame temperature and rate of flame propagation. Natural gas 
 would not be as suitable as water gas for high temperature 
 blow-pipe operations, such as welding. On the other hand, 
 natural gas is preferable to water gas in internal combustion 
 engines, in which the air and gas are mixed under heavy com- 
 pression. 
 
 Producer gas, in its washed state, while suitable for gas 
 engines, is not as well suited as water gas for high temperature 
 operations, such as forging or welding, yet with regenerative 
 furnaces it is extensively used for melting steel. The design 
 and operation of the furnace favor a field of usefulness 
 which is not disclosed by an analysis of the gas itself. 
 
 Both these gases and the air required for their combustion 
 may be preheated to a high temperature in regenerative fur- 
 naces. If natural gas were employed in the same furnaces, 
 the preheating would be limited to the air alone, because the 
 natural gas, by reason of its chemical composition, would dis- 
 sociate in the regenerative chambers at high temperatures. 
 
 Many examples from every-day practice with various forms 
 of fuel could be given to illustrate the point not generally ap- 
 preciated, that the difference in composition or "chemical 
 form value" of industrial gases, the influence of the 
 quantity of air supplied for combustion, and the design 
 of the appliance, denote fields of usefulness and limitations 
 which are not revealed by the customary B. t. u. com- 
 parison. 
 
 The distribution of natural gas is frequently affected in cold 
 weather by the formation of solids in the pipe lines. The dis- 
 
 tribution of carbureted water gas under similar conditions 
 frequently results in the deposition of oil in the pipe lines re- 
 sulting from condensation of certain hydrocarbons peculiar to 
 this gas. Producer gas, while relatively cheap and less susceptible 
 to such conditions in transportation, is not suitable for general 
 distribution by reason of its low heating value and unusually 
 high percentage of incombustibles. 
 
 By reason of their composition, gases such as acetylene or 
 blue water gas have a more or less well denned field of usefulness, 
 which makes them unsuited for the average domestic or industrial 
 heating requirements. 
 
 "City gas" is well adapted to the average industrial and 
 domestic heating operations. As a domestic fuel it has become 
 almost indispensable, particularly in congested districts. An 
 efficient extension of its use is highly desirable for the influence 
 it will exert on conditions of living and manufacturing and in 
 conservation of fuel resources. Its field of usefulness in industrial 
 heating, at present, is narrowed by relatively high price and 
 comparatively inefficient appliances. 
 
 The prevailing high price of "city gas" is very largely 
 due to existing costly and wasteful methods employed 
 in its manufacture and distribution an inheritance from 
 the days when gas was used primarily for illumination. This 
 results either in a needless production of "domestic coke" 
 or the use of oil and anthracite coal, which could be well 
 diverted to more essential purposes. 
 
 The improvement of electric appliances, resulting in an 
 extension of the use of electricity for many industrial heating 
 operations which could be efficiently conducted with gas, is 
 gradually developing an appreciation of the fact that the cus- 
 tomary methods of gas manufacture and utilization must 
 be superseded by others better adapted to present-day 
 conditions if the gas industry is to survive and render 
 its full measure of service. 
 
 The need may be supplied by a "fuel gas" generated through 
 complete gasification of bituminous coal, under standards which 
 will eliminate the oil or anthracite coal or "domestic 
 coke" to maintain obsolete candle-power requirements 
 or unnecessarily high heat-unit value. The heating value 
 could be lowered to approximately 400 B. t. u., which, with 
 suitable chemical composition to meet requirements of flame 
 temperature and odor, would be well suited to present-day 
 domestic and industrial conditions; for, as indicated by the 
 chart on page 37, it would be substantially equal to the present- 
 day "city gas" in heating value. 
 
 Low-priced gas of the proper heat value and chemical 
 composition is not in itself sufficient, because the cost and 
 nature of service to the consumer are determined not by 
 price alone, but by the quantity consumed and the design 
 of heating appliances. The appalling waste of natural gas 
 in the operation of industrial furnaces, which generally lack 
 the essentials of air control and dampers provided with the 
 common coal kitchen range or house heater, and the influence 
 of excess air in lowering the heating value of gases, indicate 
 the influence of furnace design and operation upon the 
 quality and cost of the heating service. 
 
 Electricity, at a much higher price on equivalent energy 
 basis, has outdistanced gas for many industrial heating 
 operations; not always by reason of inherent advantage in 
 electricity itself, but by reason of its use in more efficient 
 furnaces or other appliances. A comparison of the relative 
 thermal efficiency of the average gas appliance with electrical 
 appliances offered for the same purpose, indicates the need for 
 improvement and the influence of the design and operation 
 of equipment upon the cost of product or heating service, 
 of which the price of fuel is but one factor. 
 
 36 
 
COMPARISON OF INDUSTRIAL GASES 
 
 APPROXIMATE COMPOSITION ENERGY CONTENT AND CALORIFIC INTENSITY 
 
 OF 
 
 GASES AND COMBUSTIBLE MIXTURES 
 
 D-17 FURNACE DESIGN AND OPERATION NOT CONSIDERED 
 
 292O 
 
 oot- 
 
 00' 
 
 00 H 
 
 1U 
 
 u 
 00 
 
 .CfllR. ftND QftSES flT 3TF flND 
 
 INCHES OF MERCURY.). 
 
 -^00* 
 
 -3<CC 
 
 =. -V - 
 
 113 
 
 SS 
 
 ^ 
 
 ^H, 
 
 \ 
 
 ;gzi^ 
 
 -t3000j 
 
 ~*-^ 
 
 - C fl 
 
 .87. 
 
 47 
 
 85, 
 
 ^B 
 
 se>_ 
 
 ^s 
 
 fl_ 
 
 50 
 
 8&_ 
 
 ^7 
 
 24C 
 
 1300- 
 
 100 
 
 53 
 
 .67_ 
 
 _03 
 
 _Sfo_ 
 SO" 
 
 -o ^ccJ 
 5 
 
 .0 fecoJ 
 
 83. 
 
 AT' 
 
 *JL 
 
 $R-ier30 
 
 Ml 
 
 3 r-> 
 
 0- 
 
 3 ~& 
 
 I 
 
 fl fl CflLOI^IFIC INTENSITY CTHEOieETlCftL OK SUPPLY) 
 
 B B NET B.T.U. PER CUBIC FOOT OF COMBUSTIBLE MIXTURE tTHEOieETlCflL flllC 
 
 C C CflLORtFIC INTENSITY OOQ% EXCESS fill?) 
 
 D NET&T.U. PEW CUBIC FOOT OF COMBUSTIBLE MIXTURE (100^ EXCESS fllfO 
 
 E E NET BT.U. PER CUBIC FOOT OF GflS 
 
 NITROQEN IN flirt 
 
 OMQEN IN 
 
 INERT5 IN 
 
 W- ONE CUBIC FOOT OF QflS 
 
 X - THEORETICflL fllR SUPPLY FOI^ COMBUSTION 
 
 OF ONE CUBIC FOOT OF Qfl5 
 > - COMBU5TIEH.E MIXTURE^ ONE CUBIC FOOT OF QflS 
 
 PLUS flIR SUPPLY 
 Z - ONE CUBIC FOOT OF COMBUSTIBLE MIXTURE 
 
 COMBUSTIBLE PLUS OX*QEN 
 
 (ONE cu. FT. OF 
 
 COMBUSTIBLE MIXTUREj 
 
 y CONTINUOUS PROCESS 
 
 UTIUZINQ HOT COME FOP WflTER QflS 
 FIND BLOW-UP QflS TO MEflT f?CTOI?T5 
 
 OIL QflS MflOE WITH 
 HKED RETORT OR 
 
 .1 
 
 (3 
 
 ^ 
 
 T^ in 
 
 'N 
 
 r 
 
 <r 
 
 
 1 
 
 a 
 
 
 t^ 
 
 K 
 
 
 j _ 
 
 c 
 
 111 
 
 i-r- 
 
 
 
 
 U 
 
 
 ^ 
 
 3 
 
 
 
 
 2 
 
 1 
 
 
 i 
 
 V 
 
 
 |]R 
 
 S - 
 
 7 
 
 r. 
 
 
 
 
 1 ^ 
 
 > i 
 
 4 
 
 -3 
 
 Z 
 
 H. 
 
 d 
 
 wxvz W x>r 
 
 syppyO 
 
Composition of Industrial Fuel Gases 
 
 HE composition of industrial gases, their com- 
 bustible mixtures, and products of combustion, 
 are essential factors governing the selection of 
 gases and suitable equipment for the production 
 and application of heat, power or light. 
 
 When a gas is to be used as a reducing agent or for 
 some special purpose not requiring combustion, the composition 
 of the gas itself is generally all that need be considered. When 
 employed as a source of heat energy, however, it is necessary 
 to consider many other factors outlined by the chart on page 
 33, with particular reference to the influence of the composi- 
 tion of the gas or its combustible mixture upon the 
 nature of the operation to be conducted and the design of 
 apparatus to be employed for the generation and application 
 of heat. 
 
 When the material difference in B. t. u. value of the common 
 industrial gases is considered together with the comparatively 
 slight difference in heating value of their combustible mixtures, 
 it is apparent that chemical composition is of greater im- 
 portance than B. t. u. value in determining their field of 
 usefulness. 
 
 The quantity of inerts or incombustibles is relatively 
 small in the majority of industrial gases, with the exception 
 of producer gas, of which over 60% is inert matter. The inert 
 content is important insofar as it relates to the increase in 
 volume of gas or combustible mixture necessary to furnish a 
 given amount of heat energy, and to the nature and cost of 
 equipment and operations necessary for manufacture and dis- 
 tribution; but it is apparent from comparison of the inert 
 content of the combustible mixtures of the different gases that 
 the heating value of the gases is determined more by the 
 elements forming the combustibles than by the per- 
 centage of inerts in the gases or in their combustible 
 mixtures. 
 
 In the generation and utilization of heat, we are con- 
 cerned more with the heating value and composition of 
 the combustible mixture than with that of the gas itself, 
 
 although the composition of the gas enters into the problem 
 of distribution, as is illustrated by the action of carbureted 
 water gas, oil gas and natural gas in cold weather. 
 
 The relative importance of chemical composition, with 
 reference to both the character of the heat released and the 
 chemical influence of the products of combustion upon the 
 product to be heated or heating apparatus, is not generally 
 appreciated. The striking changes resulting from the 
 mixture of gas and the air necessary for combustion, 
 the further changes following ignition and combustion, 
 and the influence of excess air, are illustrated by the chart 
 on page 39. 
 
 Consideration of the comparatively large volume of products 
 of combustion of each gas, which are heated to the maximum 
 temperature of the heating process, will indicate the economies 
 attainable through efficient utilization of the spent gases 
 to perform useful work. The heat in these gases may be utilized 
 to preheat the air or fuel prior to combustion, or, as is generally 
 more desirable, to preheat the material before it is exposed to 
 the final working temperature. 
 
 The spent gases may be considered as a vehicle for 
 conveying heat in the manner that a wire is employed in con- 
 veying electricity. So-called quiescent atmospheres do 
 not actually exist. The advantages that result from the 
 transfer of heat by convection, and the natural motion of hot 
 gases created by a temperature differential, regardless of the 
 source or manner of heat generation, indicate the possibility 
 of utilizing an apparent disadvantage in composition not only 
 for effecting economy in fuel but for improvement in methods 
 of heat application. 
 
 The efficiency of such utilization is dependent upon 
 
 the design of the furnace or other appliance, and particularly 
 the method of heat application and manner of handling the 
 material and exposing it to the heat. 
 
 The field of usefulness of any gas is not entirely de- 
 pendent upon the B. t. u. value or composition of the 
 combustible mixture or products of combustion. The 
 
 design of equipment and method of releasing heat exert no 
 small influence upon the operating result, and necessitate con- 
 sideration of the physical conditions governing the design of 
 mixers, combustion chambers, rate of energy input, temperature, 
 time and other factors which are not apparent in the gas itself. 
 
 The comparatively high calorific intensity of water gas makes 
 it unsuited to certain forms of equipment, such as gas engines, 
 which may be employed to advantage with others, such as 
 natural gas, city gas or producer gas. This relation may be 
 reversed in other operations requiring the use of blow torches 
 or special heating equipment for high temperature operations. 
 
 The composition of the products of combustion must 
 be considered in relation to its influence upon the product, 
 
 because furnace atmosphere plays an important part in some 
 processes which may require either reducing, neutral or oxidiz- 
 ing conditions. 
 
 The apparent advantages of a comparatively cheap 
 fuel may be offset by the chemical action of the resultant 
 gases upon the process or apparatus, which would necessitate 
 modifications in the furnace design or process in order to retain 
 the advantage that may be represented by the form or price 
 of such fuel. This is illustrated by the practice of employing 
 crucibles for melting certain metals to decrease the possible 
 effect of oxidation, of packing material in sealed boxes or pots, 
 and by the muffle type of furnace employed for vitreous enamel- 
 ing; in each case permitting the application of heat without 
 contact between the material to be heated and the products of 
 combustion. Special atmospheres may be secured in muffles 
 by passing suitable gases into the muffle, which may or may 
 not be sealed. 
 
 Such limitation is not confined to fuels alone, as it is 
 
 frequently encountered in the arc or resistance methods of 
 releasing heat from electricity due to the gasification of the 
 electrodes or resistance material. In most cases it is desirable 
 to maintain neutral or reducing atmosphere in the heating 
 zone to protect the material from oxidation. While this may be 
 readily accomplished with most fuels in properly designed 
 furnaces by control of the air supplied for combustion, it is 
 comparatively difficult with others. Such a neutral or reducing 
 atmosphere may be readily secured in electric furnaces releasing 
 heat through some form of carbonaceous resistance material, 
 while a different form of resistance material may necessitate the 
 use of a material such as oil to provide the proper atmosphere 
 in the heating zone, even though the heat itself is generated by 
 an electrical process. 
 
 The gases, such as coal gas, carbureted water gas, etc., 
 commonly known as "city gas" of about 600 B. t. u., have 
 a lower flame temperature than unmixed blue water gas of 
 about 300 B. t. u., although the B. t. u. values of the combustible 
 mixtures are approximately the same. The difference in chemical 
 composition of the gases themselves, resulting in a compara- 
 tively insignificant difference in odor, which is frequently desir- 
 able in order to detect leaks, makes the so-called "city gas" 
 generally preferable for distribution to domestic consumers. 
 Likewise, the difference in chemical composition of the 
 combustible mixture or the products of combustion 
 frequently determines the field of usefulness in heat, 
 power or illumination, regardless of price on a heat-unit 
 basis. 
 
 The fundamental significance of chemical composition, 
 as affecting the quality and cost of product, must be con- 
 sidered in the selection of gases and of equipment for 
 the transformation and application of their energy values. 
 
 38 
 
D-21 
 292O 
 
 COMPARISON OF INDUSTRIAL GASES 
 
 VOLUMETRIC COMPOSITION 
 
 OF 
 GAS. COMBUSTIBLE MIXTURE AND PRODUCTS OF COMBUSTION 
 
 CRR6URETTED WflTER Qfl5 
 I I I 
 
 _ ETH^LENE 
 CwHM- ILUUMINflNTS 
 cO-CflRBON MONOXIDE 
 Qz- OA^QEN 
 CO s -CflRBON CXOWOC 
 HaO- WfTTER 
 
 I i 
 
 fl= VOLUMETRIC COMPOSITION 
 OF QflS. 
 
 B= COMBUSTIBLE MIXTURE 
 THEORETlCflL RIR SUPPLY 
 
 C = PRODUCTS OF COMBUSTION 
 THEORETICAL fill? 5UPPLV. 
 
 D= COMBUSTIBLE NllXTUf?E 
 100^ EXCESS flll? 
 E'PPCODUCTS OF COMBUSTION 
 EXCE35 fllf? 
 
 39 
 
 Fig. 
 
Utilization of Fuel Resources 
 
 HE so-called "fuel problem" is but one factor 
 in the real problem, i. e., the efficient utilization 
 of all the energy and commodity values in natural 
 fuel resources. 
 
 As regards the energy values alone, the problem 
 involves the production, transportation and utiliza- 
 tion of fuel in the application of heat, power or light. 
 
 A field of usefulness exists for each form of fuel used 
 in suitable apparatus. The scope of the respective fields is 
 not measured solely by price and thermal value, but includes 
 that intangible value due to the physical or chemical association 
 of the fuels and the mechanical form of the apparatus. This 
 element may be defined as "form value," in contrast to thermal 
 value as commonly expressed in "heat units" (B. t. u.) or "heat 
 balance. " A survey of the field is incomplete without 
 consideration of all the factors that govern the produc- 
 tion and transportation of fuel, and the selection of the 
 proper form of fuel and proper equipment for the efficient 
 application of heat to useful work. 
 
 "A solution of the fuel problem" is frequently advanced 
 by advocates of some one form of fuel, or those urging the 
 proposition that the utilization of fuel for the generation of 
 electricity, or production of gas in super-transforming stations, 
 is the logical method of . conserving fuel resources in meeting 
 the modern demand for energy service. 
 
 However, the requirements for power, illumination, industrial 
 and domestic heating, and the chemically important need for 
 by-products are so interwoven that all these needs cannot be 
 separately treated. The energy and commodity require- 
 ments must be appraised in their interdependence, and 
 determination made of the most practical means for 
 meeting these requirements. Economies that may be 
 effected in production and transportation of fuel must be con- 
 sidered together with the possible economies in utilization of 
 different forms of solid, liquid and gaseous fuels and electrical 
 energy in more efficient appliances adapted to each. 
 
 The possibility of improving present methods must be 
 borne in mind, as well as the advantages likely to result from 
 the substitution of better methods adapted to present-day 
 conditions. The quantity of fuel required to meet the country- 
 wide demand has grown to such a stupendous total that its 
 provision in the customary forms is becoming increasingly 
 difficult and results in tremendous wastes of material and effort. 
 
 The waste in production of oil is far greater in proportion 
 than that of coal, but the waste in transportation and 
 utilization is proportionately greater with coal. The handling 
 of coal engages over one-third the freight capacity of the 
 country, while the more flexible form of oil favors its simple 
 and cheap distribution through an extensive system of pipe 
 lines thousands of miles in length. Conversion of. the heat 
 energy in coal to the form of gas simplifies the problem 
 of distribution and utilization, particularly in congested 
 areas, which condition warrants consideration of "form value" 
 in distribution as well as in utilization. 
 
 The traffic congestion at the terminals and on the streets, 
 from the distribution of coal and removal of ash, and the enor- 
 mous losses and property damage due to smoke, soot and ash, 
 as also the loss by destruction of valuable by-products, etc., 
 following the transportation and use of coal in the customary 
 manner and form, are in marked contrast to the conditions 
 made possible by substitution of the more mobile forms of energy 
 such as oil, gas or electricity. These contrasting conditions 
 
 illustrate the influence of the "form value" of energy and 
 appliances upon the cost of transportation and ultimate 
 cost at the point of consumption. 
 
 In 1915, before the price of coal was advanced by war con- 
 ditions, the average cost of bituminous coal at the mines was 
 less than $1.25 per ton. The difference between this figure 
 and the price paid by the consumer represented the charges of 
 the carriers and dealers, from which it is apparent that any 
 economies possible through improved methods of pro- 
 duction would have exerted very little, if any, influence 
 in reducing the price to the consumer. 
 
 As an illustration of what can be gained by transforming 
 its energy into other forms, in addition to the saving in trans- 
 portation: The same coal utilized in the by-product coke oven, 
 or the central station gas plant by the coal-gas process, has 
 been made to yield domestic coke, gas for heating and illumina- 
 tion, and by-products valued at about $15. If its energy values 
 were entirely converted into a gas suitable for the average 
 domestic and industrial heating requirements or for the genera- 
 tion of power, the yield in gas and by-products would be over 
 $25. Additional gains resulting from the transportation 
 of energy in the form of gas through pipes, or electricity 
 by wires, are obvious, including the diversion of coal-carrying 
 equipment to more essential and profitable uses; the saving in 
 fuel incident to better methods of heat application possible 
 with gas or electricity, and a general improvement in living 
 conditions. 
 
 The losses and likewise the opportunities for improve- 
 ment in the utilization of fuel are shown by the diagrams 
 on page 41, representative of current practice. When the 
 additional losses in the production and transportation of 
 fuel before its combustion are considered together with the 
 still greater losses in the application of heat, power or 
 light after transformation, the condition is still more striking 
 and suggests the desirability of improvement in methods of 
 utilizing the energy resources. 
 
 An extension of the electrical program is desirable to 
 
 meet the need for power and illumination, but the limitations of 
 price and "form value" in the arc, resistance and induction 
 methods of releasing heat, and the special nature of electrical 
 equipment, limit the field of electricity as a substitute for fuel 
 in heating operations. 
 
 Reconstruction of the "city gas" industry offers an at- 
 tractive field for development because of the opportunity for 
 better utilization of the heat energy in bituminous coal and the 
 economic progress that will follow an extended use of cheaper 
 gas. Better methods of gasification and distribution, 
 elimination of the problems incident to the use of oil, 
 anthracite coal and "domestic coke," and utilization in 
 improved appliances, such as furnaces, gas engines, etc., 
 should result in better and cheaper methods of utilizing 
 fuel resources, with advantage to the community as well as 
 the gas industry. 
 
 That one coal pile and transforming station may be a 
 source of by-products and energy in the form of gas or 
 electricity for domestic and industrial heating is not an 
 idle dream. Every essential step has been proved in practice. 
 Public opinion needs to be awakened to the advantages that 
 will follow further extended use of the more mobile forms 
 of heat energy, such as gas or electricity, and to the fact 
 that those advantages can be gained, however, only through 
 far-reaching changes in present methods of provision and 
 utilization. 
 
 40 
 
HEAT DISTRIBUTION IN ENERGY CONVERSION PROCESSES 
 
 ECONOM.C VALUE OF BY-PRODUCTS. POSSIBLE HEAT RECOVERY AND 
 THE EFFECT OF OPERATING CONDITIONS NOT CONSIDERED 
 
 HOUSE HEfTTING BOILER 
 
 BUREflU OF MINES 
 
 <*0% CHIMNEY LOSS 
 
 207o UNCOVERED PIPING 
 
 5% POOR FIRING 
 
 3 10% DIRTy FLUES 
 -4XJ-257. HEflT TO ROOMS 
 
 CflRBURETTED WflTER GflS 
 
 FUEL" 
 
 VD.3.R. CO. 
 
 - ILL. GEO. SURVEY - 
 
 5% WflSTE QflS 
 RflDlflTION -CTC, 
 
 57. TflR-rrc. 
 
 3% CflRBONIZflTION 
 
 6% TO 10% fl5H 
 5% TO fc% TflR 
 LflMPBLflCK 
 
 TflR flND BY-PRODUCTS 
 
 22% BLOW-UP QflS flND 
 PROCESS L055 
 
 CflRDURETTED WflTER GflS 
 
 117. BLOW-UP Gfl3 
 71. fl3H 
 
 3.3% SENSIBLE HEflT 
 BLUE WflTER Qfl5 
 
 "FUEL" GAS 
 
 BV CONT^OV, moce,, mw* HOT cone 
 
 TOR WflTEK GHS flNO BLOW-UP G TO MEBT RtTOTT3. 
 
 POWER PLflNT (NON-CONDENSING) 5TEflM POWER PLflNT (CONDENSING) 
 
 RUPTAII OF Miwre _ ._ * ' 
 
 BUREflU OF MINES 
 
 30% BOILER L053 
 
 -7.5% flT ENGINE SHflFT 
 
 STEflM BOILER 
 
 CURRENT FRHCTICE 
 
 MOISTURE 
 
 15% CHIMNEY LOSS 
 
 5% RflDlflTION 
 -707. IN STEflM 
 
 60% EXHflUST 
 
 2.5% FRICTION -ETC. 
 
 SUCTION PRODUCER GflS PLflNT 
 
 R.O. WOOD CO., MODIFIED 
 
 20% PRODUCER LOSS 
 5% FRICTION flND RflDlflTION 
 . EXMflUST 
 
 ^j 32% COOLING 
 fTT ENGINE ShflFT 
 
 - BUREflV Of MINES - 
 
 25% BOILER L033 
 
 5B% CONDENSER 
 
 FRICTION flNO RflOlflTION 
 -137. flT ENGINE 5HflFT 
 
 COTTON MILL (flVERflGE) 
 
 BUItEflU Of MINES, MODIFIED 
 
 35% BOILER LOSS 
 
 57. RflDlflTION 
 67. FRICTION 
 
 CONDENSER 
 
 *-l7. flT ENQINE SHflFT 
 *===== fe% TRflNSMISSlON LOSS 
 
 3% ENERGY UTILIZED 
 
 GflS-ELECTRIC PLflNT 
 
 - fl.S.M.E. - 
 
 20% G05 PRODUCER 
 
 n% COOLINQ 
 
 Y///A 30% EXMflU5T 
 
 77. ENGINE flND QENERflTOR 
 BUS BflRS 
 
 SUPER STEflM- ELECTRIC PLflNT 
 
 BUREflU OF MINES 
 
 ICE MflKINQ PLflNT 
 
 -RS.R.E. 
 
 81 % CONVERSION LOSS 
 
 BUS BflR.5 
 
 41 
 
 30% BOILER LOSS 
 
 lfc% flUXILIflRIPS flND PIPING 
 
 33% CONDENSER 
 
 FRICTION 
 COMPRESSOR LOSS 
 
 -/k-157. ICE MflKINQ EFFECT 
 
 Fig. 
 

 
 
 
 
 g 
 
 
 
 
 
 
 
 T3 
 
 
 C-] 
 
 
 
 
 
 
 
 TJ 
 
 
 
 
 
 
 
 
 8 
 
 s 
 
 
 
 
 
 
 
 S 
 
 
 P 
 
 
 
 
 
 
 
 03 
 
 
 CM 
 
 CO 
 
 055 watt seconds. 
 78.3 ft. Ibs. 
 
 07.6 kilogram meters. 
 
 ,0002931 kw. hour. 
 
 ,00039305 h. p. hour. 
 
 .0000685 Ib. carbon oxidiz 
 
 .001030 Ib. water evap. f 
 
 and at 212 C F. 
 
 000 watt hours. 
 
 .341 h. p. hours. 
 ,655,000 ft. Ibs. 
 
 ,600,000 joules. 
 
 3 
 
 -4J 
 
 03 
 -* 
 
 67,100 kilogram meters. 
 .234 Ib. carbon oxidized. 
 
 .52 Ibs. water evap. from 
 
 fa 
 
 o 
 
 CM 
 
 CM 
 
 S 
 
 2.77 Ibs. water raised froi 
 
 fa 
 CM 
 CM 
 
 S 
 
 .7457 kw. hour. 
 
 ,980,000 ft. Ibs. 
 
 3 
 
 
 
 10 
 
 73,745 kilogram meters. 
 
 .174 Ib. carbon oxidized. 
 
 .62 Ibs. water evap. from 
 
 fa 
 CM 
 CM 
 <-> 
 
 ai 
 
 7.0 Ibs. water raised from 
 F. to 212 F. 
 
 H t- 
 
 rH 
 
 
 
 o 
 
 o 
 
 o 
 
 
 H 
 
 rH CM 
 
 os 
 
 CO 
 
 CO O 
 
 CO 
 
 
 CM 
 
 
 
 
 H 
 
 CM 
 
 CM 
 
 o 
 
 CM 
 
 
 IH 
 
 .8 s 5 
 
 S 2 
 
 "81 
 II 
 
 * en to 
 
 CO OO CO CO 
 
 ^ eg t- ^_j 
 
 S o 
 
 I 
 
 i* It A 
 
 f . bt 3 ja . 
 
 . 3 O O ~ 
 
 ./ G = "-*; 
 IS J . a g*2 
 * * S 2 3 
 
 TF r-l TT Tf CM CM CO 
 
 oo oo -: r CM >- co 
 N . "? r- o . 10 . 
 
 
 O P 3 is co 
 +J p u CM 
 
 8 ;* S 
 
 * X 1 w W 
 
 3 ^O QJ .S 
 
 5 "8 
 
 C8 *> 
 
 h -3 - 
 
 ^flll 
 
 S ^ S ^ fc ^ 
 
 ft a G 3 v 
 
 .2 . "> * j S 
 
 g 3 'E S P S 
 
 P3 
 
 c S . 
 
 T ft o* 
 
 cr ^ 
 ^ 
 
 r-l O 
 
 O 
 <UJ> 
 
 o 
 
 t-tH T-H 05 
 L.^ 00 t-10 00 g 
 
 ^ U> 04 ^ CO 
 
 tij CO O rH O <N 
 
 3,* 
 
 S-- 
 
 ^X 
 
 ooq 
 
 S 8 
 
 6 
 
 ft 
 
 fe 
 
 c 
 
 i 
 
 <U ft CO ft 03 
 
 'S j.2 j.8 
 o 3 ^ 3 >H 
 
 3,j^,j^ 
 
 O . oS . ro 
 
 * MOPQO 
 
 CQ 
 
 82 
 
 c 
 
 Si 
 
 y 'no aad spunoj 
 
 04 
 
 S co 
 
 1 * 
 
 OOt- ^H TfTf m OOU5CONCO-^*CDr-tU5<OiH^HU3e<lOi 
 tOr-l r-l 100 -<t 50 tC CO -* CO [- 10 CO 00 > 10 to Til 
 iHT|i U5 1/iCM TJI C-5OTru5kOCOt-<DT|iTp(M-(CO -^* 
 
 X^IABJO oyiDadg 
 
 005 
 t- 5O 
 
 <NO 
 
 O> O CO 1O U5 (N>-l Ot- Tl< OOOOOOO5 OO5 
 OOCO ^H COeDTPOt-CO-^CCCOCSlOCDCOO'H 
 
 ooo> t^ i-<oi>oJoorHcsic>i>5Ti<o6iartC- 
 
 qi jad -n-vg uoisn j 
 
 JO ^B3H U3^Bq 
 
 M IS 
 
 O5 CO t- D i 
 
 i COOS i OOCM 1 
 
 
 0<0 
 
 OON 
 CO C- 
 
 t-O5 rt o : 
 
 t-N TT -H j 
 
 : oooo i us in : 
 : TII ; TTCM | 
 
 
 TfOS 
 * T!" 
 H 
 
 }9H 
 
 OyiDaag 93BJ3AV 
 
 co 
 
 00 -H ^ 
 
 co us a- 
 
 IM O C 
 
 oot- en 
 
 O tH U3 O" 
 
 O CO "-< (M CO Tf t- 
 
 1-1 o 1-1 oa o o i- 
 
 en CM if 
 
 10 ooo oco OIN 
 
 O5fHCOlO<OlOt-- 
 OrlOOOOO,- 
 
 cr 
 
 -- 
 
 c^ 
 c 
 
 00 
 
 05 
 O O5 
 OO 
 
 o o c 
 
 O O O O O O G 
 
 OOOOOOOG 
 
 c 
 
 'rHO 
 
 j -aaa 
 
 IUIQJ BaffiBIl 
 
 t-o o 
 
 iH tO O 
 MiH 1O 
 
 3-H 1OO O^H C 
 
 o oo TP ic o w c 
 
 ?S O5 O5 O CO <D C** 
 -1 -H r-KN CM (N 
 
 IM SO OOCM O Ci- 
 
 CO T(i OS CO O IO 
 IO tO r-l IO C^ -^ C\ 
 TC IMCO CO rH V 
 
 c> 
 
 L." 
 
 . 
 
 tc 
 
 00 <M tO 
 
 <M so 00 
 i-l t- 
 
 co 
 
 
 Aluminum 
 Antimony 
 
 Brass.. _ . 
 
 . B'O 1 
 
 -Isj 
 6 e"5 
 
 ll 11 s 
 
 60 i JJS 
 
 a Es -dSc 
 4,11 ^^^ 
 '|I||S* B .; 
 
 3.2 tSJj: c c-S 
 
 SBZ^eSwHHP 
 
 c 
 
 1 
 
 1 
 
 E^ 
 
 fa 
 
 flo, 
 
 Is 
 
 ^ K 
 g^t, 
 
 S^ E 
 
 >^N 
 
 S S'-s 
 
 OQ '-g 
 
 E S "S3 
 
 4t 
 
 S3 -1 
 
 .-o 
 
 
 
 
 
 
 
 CO 
 
 to 
 
 05 
 CO 
 
 Tl 
 Tf 
 
 , CM 
 
 - 
 
 III 
 
 II 
 
 ' 
 
 0.000393 
 
 0.00156 
 
 - 
 
 en 
 
 CO 
 
 
 o 
 o 
 o 
 
 1 
 
 o 
 
 o * h 5 
 
 CO 
 
 o 
 
 CO 
 
 oo 
 
 CM 
 1O 
 CM 
 
 
 - 
 
 t- 
 
 Tji 
 
 CM 
 
 1O 
 CM 
 O 
 
 3 
 J 
 
 M 
 
 * Jj 2. 
 
 CO 
 
 - 
 
 00 
 
 1 
 
 CO 
 
 5 
 
 ie 
 
 CM 
 
 - 
 
 S rt o 
 
 ^w 
 
 3 s 
 
 - 
 
 0.00029 
 
 0.001162 
 
 t- 
 
 1O 
 T? 
 t- 
 
 O 
 
 CO 
 O5 
 (M 
 
 
 
 O 
 
 < 
 
 OQ 
 
 = '- 
 
 -OS 
 
 <is CQ 
 
 P P| 
 
 w w D 
 
 A. Calorie 
 B Calorie 
 per hour 
 
 g g^ s I 
 
 M * 3 C 
 
 JJdl 
 
 < CO 
 
 ^1 00 G 
 
UALITY and cost of heat-treated products are greatly influenced by type layout - 
 
 P We * atmg a ^ ^^ e< ? ui Pnt and form of heat enJ^pod 
 
 We make a specialty of designing and constructing modern industrial 
 
 fuel or electricity ' for the 2MS <*!? 
 
 Our practical experience of over thirty years is illustrated by the following list of 
 ' "' h "" buUt '" 
 
 ANNEALING FURNACES. Rolling mill type. Improved underfired 
 downdraft design with perforated floor to permit delivery of 
 heat to bottom and top of charge, with or without recuperation- 
 improved side-fired design for comparatively low charges. 
 Single or multi chambers; single or double end; all sizes for ferrous 
 and non-ferrous metals in form of ingots, bars, rods, sheets, 
 coils, wire, tubes, etc.; miscellaneous stamped or drawn parts 
 such as cups, shells, etc.; light forgings, castings, etc. 
 Automatic conveyor, revolving (with or without retort), rotary 
 table and beam" types for ferrous and non-ferrous pieces 
 of uniform size in large quantities, with provision for automatic 
 charging, preheating, heating, discharging, quenching, draining 
 and delivery, as required. 
 Semi-automatic pan and pusher types for irregular shapes 
 
 carried on pans or trays, or regular shapes moved on rails. 
 Bright annealing for non-ferrous metals; continuous conveyor 
 
 type with water seals; pot type for fine wire, etc. 
 Car type with removable hearth for heavy and irregularly shaped 
 
 castings, forgings, etc. 
 Car-and-ball type for annealing wire, sheets, etc., in packing boxes; 
 
 heat-treatment of large forgings, castings, etc. 
 Removable roof type for steel castings, heavy forgings, etc. 
 Side-opening type with movable partitions to accommodate rela- 
 tively small parts or shafts over 100 ft. long. 
 Stationary type with single or multi chambers, with or without 
 
 charging machines or packing boxes. 
 Stoker-fired type for miscellaneous heavy work. 
 
 Direct recuperative type for recovery of heat in spent gases or in 
 outgoing hot charges to preheat incoming charge; continuous 
 or intermittent heating and handling. 
 BAKING FURNACES. For drying wire, miscellaneous metal pieces, 
 
 heat-treating chemical products, etc. 
 
 BILLET HEATING FURNACES. Continuous and intermittent 
 types for ferrous and non-ferrous ingots, billets, cakes, etc., for 
 rolling or forming; heat-treatment of uniformly shaped pieces, 
 such as car axles, etc.; single or multi-chamber design, with 
 different arrangements of working openings. 
 BLAST GATES. Improved air-tight blast gate for air, etc.; special 
 
 types for liquids, powders, etc. 
 BLOWERS. Turbo, positive pressure and fan types for air, with belt 
 
 or direct motor drive; argand or turbo types for steam. 
 BLUING FURNACES. Continuous and stationary types, with or 
 without muffles, for bluing large quantities of wire, etc.; auto- 
 matic type for miscellaneous small parts. 
 BRAZING FURNACES. For tubes, wire, etc. 
 
 BURNERS. Oil or gas 10 types in a variety of sizes for high pressure 
 steam and high or low pressure air; combination types; 
 special types for mechanical atomization of oil. 
 
 CARBONIZING FURNACES. Single and multi-chamber types, 
 with or without recuperation, in a variety of sizes with different 
 arrangements of chambers and working openings; special types 
 for carbonizing in retorts with gas. 
 
 CORE OVENS. Special designs in large sizes with movable reels, cars 
 or conveyors. 
 
 CYANIDE FURNACES. Single and twin-pot types, with or without 
 preheating chambers. 
 
 DRYING FURNACES. Rotary, conveyor and stationary types for 
 
 continuous and intermittent operations, with or without muffles, 
 for metal goods, chemical products, etc. 
 
 ELECTRIC FURNACES. Resistance type in automatic, semi-automatic 
 and stationary designs for miscellaneous heat-treatment opera- 
 tions on metallurgical, chemical, ceramic and other products 
 requiring accurate control of chamber atmosphere and tempera- 
 ture. 
 
 ENAMEL FURNACES. For burning and melting; standard muffle type 
 for coal, oil or gas; semi-muffle type for intermittent heating 
 with oil or gas and automatic control of fire; improved down- 
 draft recuperative type, with muffle, for bituminous coal, oil 
 or gas; reverberatory type for melting; electric resistance 
 type for burning continuous or intermittent operation. 
 
 FORGE FURNACES. Economizer shield type to protect operator and 
 utilize heat from working opening to preheat air for combustion. 
 Single or double end, for short or long heats, working off the 
 bar or with cut stock for serving drop hammers, upsetting 
 machines, rivet, bolt and nut machines, etc. Double end for 
 long rod heating, to serve continuous rivet and bolt making 
 machines. 
 
 Slot and magazine types for bolt heading. 
 
 Miscellaneous portable types for short end heats, tool dressing, etc. 
 Blacksmith type for general work. 
 Bulldozer type for small hammer work. 
 
 r large 8team ham ". 
 
 ~*" fuel or air - or for direct recover * 
 
 res Continuous and int.rmUtent typ.. 
 GLASS FURNACES. For melting and annealing glass 
 HARDENING FURNACES. Automatic, semi-automatic and sta- 
 
 h'?7 a H P h * ! a vanetv ? f Si2es with different methods of 
 
 HEATING FURNACE^ r" 8 ^ 3 ' P 4 tyP * ^ hardenin in batl - 
 
 HtATING FURNACES. Continuous, semi-automatic and station- 
 ary types for miscellaneous forming operations 
 
 HEAT-TREATING FURNACES Automaticf-emi-automatic and 
 stationary types, with direct or indirect heat recovery- size 
 and arrangement of chambers and working openings, methods 
 t heating and handling, etc., adapted to individual require- 
 ments, using coal, oil, gas or electricity; semi-muffle and 
 muffle types; combination types for continuous annealing, 
 normalizing, hardening, tempering, etc. 
 
 INCINERATING FURNACES. Special type, for disposal of waste 
 products. 
 
 JAPANNING FURNACES. Continuous and stationary type, in 
 
 large sizes for special drying or baking operations. 
 
 KILNS. Special designs for ceramic products 
 
 MELTING FURNACES. Stationary and tilting crucible and rever- 
 beratory types for non-ferrous metals, enamel powder and 
 special purposes. 
 
 MUFFLE FURNACES. For annealing, enameling, scaling, rust-proofing, 
 assaying and miscellaneous purposes. 
 
 OIL APPLIANCES. Burners; oil pumps; relief valves; heaters; unloading 
 hose; storage tanks; burner plates; blowers; blast gates; special 
 combustion chamber tiles; etc. 
 
 PATENTING FURNACES. For continuous heat-treatment of wire 
 
 PLATE HEATING FURNACES. For miscellaneous forming operations 
 in ship, railroad and boiler shop work; angle heating type for 
 angles, beams, rods, etc. 
 
 Continuous type for large quantities of uniformly shaped pieces 
 for hot press work. 
 
 POT FURNACES. Single and multi-pot types, with or without pre- 
 heating chambers, for heat-treatment operations in baths of 
 oil, lead, salts, etc.; melting soft metals, etc., with or without 
 spout and valve or special means of discharging or handling 
 material; special types for bright annealing, carbonizing and 
 miscellaneous processes. 
 
 REGENERATIVE AND RECUPERATIVE FURNACES. For high 
 temperature operations, such as forging, welding, melting, etc., 
 utilizing heat in spent gases to preheat air and fuel. 
 Direct recovery type, in continuous and stationary forms, with 
 single or multi chambers, utilizing heat in spent gases or hot 
 charge to preheat incoming material. 
 
 RE-HEATING FURNACES Intermittent and continuous types, 
 with single or multi chambers or doors. 
 
 RETORT FURNACES, in different types and sizes, with metal or refrac- 
 tory muffles. 
 
 REVERBERATORY FURNACES. For melting, heavy forging, etc. 
 
 RIVET FORGES. Portable and stationary types. 
 
 ROASTING FURNACES. Special types for roasting ores, chemical 
 products, etc. 
 
 ROD HEATING FURNACES. Single and double-end types for short 
 or long heats. 
 
 SCALING FURNACES, with or without muffles, for ferrous and non- 
 ferrous metal products. 
 
 SHEET AND PAIR FURNACES. Continuous and stationary types. 
 
 SINGEING FURNACES. For singeing cloth, carpet, etc., with hot 
 plates or gas flames. 
 
 SPRING FITTING FURNACES. Automatic, semi-automatic and 
 stationary types; combination fitting, hardening and 
 drawing stationary type for vehicular springs; continuous 
 and stationary types for one, two or four fitters on car springs, 
 etc. 
 
 STOKER-FIRED FURNACES. With or without recuperation, for mis- 
 cellaneous heating operations. 
 
 TEMPERING FURNACES. Automatic, semi-automatic and sta- 
 tionary types in a variety of designs and sizes; special types 
 with stationary or movable dies for saws, etc.; miscellaneous 
 designs for delicate parts, such as needles, etc. 
 
 TINNING FURNACES. Continuous type for wire, sheets, etc.; special 
 types for long tubes and miscellaneous small stamped and cast 
 parts. 
 
 TIRE HEATING FURNACES. Stationary and continuous types for 
 shrinking operations. 
 
 VARNISH BOILING FURNACES. For varnish, oils, gums, greases, etc. 
 
 SPECIAL DESIGNS OF FURNACES 
 
 for 
 Metallurgical, Chemical, Ceramic and Other Processes 
 
 43 
 
 V c^ c**^ 
 s&yVoS 
 
INDUSTRIAL FUELS 
 Comparative Cost Per Million B. T. U. at Unit Prices 
 
 BITUMINOUS COAL 
 at $5.00 per ton 
 
 NATURAL GAS 
 
 at 25c per 1000 cu. ft. 
 
 FUEL OIL at 5c per gal. 
 
 ANTHRACITE COAL 
 at $10.00 per ton 
 
 NATURAL GAS 
 
 at 40c per 1000 cu ft. 
 
 *"FUEL" GAS 
 
 at 25c per 1 000 cu. f t. 
 
 FUEL OIL at lOc per gal. 
 KEROSENE OIL 
 at lOc per gal. 
 
 CITY GAS 
 
 at 50c per 1000 cu. ft. 
 
 *"FUEL" GAS 
 
 at 50c per 1000 cu. ft. 
 
 CITY GAS 
 
 at $1.00 per lOOOcu.ft. 
 ELECTRICITY 
 
 at Ic per kw. hr. 
 GASOLINE 
 
 at 30c per gal. 
 
 ELECTRICITY 
 
 at 2c per kw. hr. 
 
 Assumed Thermal Value 
 
 B. T. u. 
 
 Per 
 Pound 
 
 Per 
 Cu. Ft. 
 
 Per 
 
 Gallon 
 
 FUELS 
 
 Bituminous Coal 15,000 
 
 Anthracite Coal 14,000 
 
 Natural Gas 950 
 
 City Gas 600 
 
 *"Fuel" Gas 400 
 
 Fuel Oil 142,000 
 
 Kerosene 130,000 
 
 Gasoline 85,000 
 
 Electricity (3411 B. t. u. = 1 kw. hr.) 
 
 *Gasification by continuous process utilizing hot coke for water gas 
 and blow-up gas to heat retorts. 
 
 1.67 
 
 
 
 
 
 
 
 " ' -*-- ' 1 1 1 
 
 i.l. 
 
 
 $0.50 1.00 2.00 3.00 
 
 4.00 5.00 
 
 6.00 
 
 DOLLARS PER MILLION 
 
 B. T. U. 
 
 
 Fig. 28 
 
 
 
 Quality and cost of finished product not cost of fuel, cost of labor, mere 
 tonnage, nor indication of uniform chamber temperature are the determi- 
 native tests of industrial heating operations. 
 
 "FURNACE AND FUEL TO SUIT CONDITIONS " 
 
 is our rule governing consideration of new or improvement of existing industrial heating equipment 
 to suit your needs under your plant conditions. 
 
 We make inspection of plant, devise methods of heating and handling material, furnish complete 
 industrial heating equipment adapted to your particular plant conditions, and guarantee results, 
 using coal, oil, gas or electricity, as your best interests require. 
 
 W. S. ROCKWELL COMPANY 
 
 Furnace Engineers and Contractors 
 
 50 CHURCH STREET NEW YORK 
 
 (Hudson Terminal Bldg.) 
 
 Works: NEWARK, N. J. 
 
 Branches: Chicago Cleveland 
 
 Detroit 
 
 Ellsworth Bldg. Engineers' Bldg. Majestic Bldg. 
 Britith Representative: GIBBONS BROS., Ltd., Dudley, Wore., England 
 
 44 
 
DEPARTMENT 
 
 
 
 FO RWNO.DD6,40m 
 
I