W-5 Digitized by the Internet Archive in 2007 with funding from IVIicrosoft Corporation http://www.archive.org/details/electricheatingOOwilcrich ELECTRIC HEATING BY E. A. WILCOX, E. E. Member A. I. E. E. ELECTRIC HEATING SPECIALIST GREAT WESTERN POWER COMPANY Fird Thousand SAN FRANCISCO TECHNICAL PUBLISHING COMPANY CROSSLEY BUILDING LONDON E. & F. N. SPON, LIMITED 57 HAYMARKET 1916 COPYRIGHT, 1916 BY TECHNICAL PUBLISHING COMPANY / t-1 PREFACE The utilization of electricity for heating purposes on a large scale is a development so recent that little information on the subject has yet been published outside of the trade periodicals. The wealth of printed matter concerning electric lighting practice only em- phasizes the dearth of data regarding electric heating. Yet heat by wire seems destined to a far greater fu- ture than light by wire, not only as regards the amount of current consumed, but also in the intrinsic value of its service to mankind. In his capacity as a load builder for central sta- tions the author was early confronted with the lack of recorded facts about the how and why of electric heat- ing. For his personal needs he correlated widely- scattered notes, simplified the technical treatment so that it would be intelligible to the sales prospect and brought into convenient form much of the knowledge required by the salesman of electric heating appliances. This information has been so useful to the author that it was thought that it might also be of service to others in the industry, particularly since the elec- tric cooking load has become so desirable to the cen- tral station. Hence this book. Briefly, it aims to set forth in a practical way the many uses to which electric heat may be applied. The advantages and disadvantages of various kinds of heat- ing loads are compared and many types of heating devices are explained. The relative operating costs of 365508 electric and fuel-heated apparatus are shown by tables and simple calculations. Suggestions are given re- garding approved methods of installing and using do- mestic and commercial ranges, bake ovens, water heaters and industrial heating devices. Acknowledgement is here made of the courtesy of many manufacturers in supplying cuts used to illus- trate typical equipment. E. A. WILCOX. San Francisco, July, 1916. TABLE OF CONTENTS CHAPTER I. Page Heat Energy and Electricity 1 Deman 1 for Heat — Advantages of Electric Heat — Natui'e of Heat — Temperature Measurement — Meas- urement of Heat — Specific Heat — Thermal Capacity — The Calorie — Mechanical Equivalent of Heat — Relation to Electrical Units — Latent Heat — Radi- ation — Conduction — Convection — Comparison of Fuel 11 nd Electric Heat. CHAPTER n. Domestic Lamp Socket Heating Devices 8 Importance — Electric Irons — Electric Stoves — Toaster Stoves — Chafing Dishes — Coffee Perco- lators — Tea Samovars — Tea Kettles — Table Cook- ing Outfits — Electric Grills — Food Warmers — Plate Warmers and Hot Closets — Bake Ovens — Nursery Milk Warmers — Curling Iron Heaters — Warming Pads— Immersion Heaters — Other Household De- vices. CHAPTER HI. Installation of Heating Apparatus 19 Correct Installation — Wiring for Heating Appa- ratus — Carrying Capacities of Wires — Correct Volt- age — Methods of Wiring — Exp6sed Knob and Cleat Wiring — Flexible Metallic Conduit — Flexible Steel Armored Conductor — Switches — Grounding — Ranges in Apartment Houses and Flats — Proper Position for a Range. CHAPTER IV. Electric Cooking 26 The March of Progress — Advantages of Electric Cooking — Facility of Operation — Reduction in Meat Shrinkage — Importance of Proper Utensils — Econ- omy in Range Operation — Elimination of Kitchen Chimneys — Operation by Servants — Attention to Range Users — Electric Cooking in Schools — Elec- tric Cooking in Apartment Houses — Preparation of Food. CHAPTER V. The Electric Range 42 Demand — Essential Qualifications — Types of Heat- ing Units — Types of Electric Ranges. CHAPTER VI. Commercial Cooking 68 Opportunities — Advantages — Apparatus Available — Hotel Ranges — Meat Broilers — Hot Closets— Steam Tables — AVater Heaters — Frying Kettles — Toasters — Coffee Urns — Griddles — Electric Bake Ovens. CHAPTER VII. Electric Water Heating 9?. Comparison of Fuel and Electricity — Thermal Char- acteristics of Water- — Electric Energy Required — Heat Losses — Lagging — Methods of Heating Water Electrically — Essential Features — Automatic Tem- perature and Time Control Devices — Installation of Thermal Storage Water Heaters. CHAPTER Vin. Electric Heating of Buildings 115 Use and Advantages — Comparative Costs of Fuel and Electric Heat — Electric Heating Systems — Radiant Heaters — Convection Heaters — Oil and Water Radiators — Indirect Air Heaters — Steam and Hot Water Systems — Installation of Electric Heat- ers — Calculation of Heat Requirements. CHAPTER IX. Page Industrial Heating 130 Scope of Application — Development of Field — Advantages of Electric Heat — Comparison with Fuel and Steam Heat — Heating Elements — Heating- Specifications — Applications of Electric Heat (60 industries). CHAPTER X. Electric Furnaces 145 Economic Advantages — Field — Character of Service — Classification — Advantages and Limitations — Heat Energy Required — Furnace Walls — Furnace Elec- trodes. CHAPTER XI. Electric Furnace Applications 156 Fundamental Considerations — Production of Ferro- . Alloys — Smelting of Iron and Other Ores — PioJuc- tion of Graphite and Carbide — Electrolytic Furnace Processes — Aluminum — Nitrates — Steel — Resistance Furnaces — Induction Furnaces — Arc Furnaces. CHAPTER XII. Low Temperature Electric Furnaces and Ovens 174 Field — Advantages — Processes — Carbon Resistance Type — Metallic Resistance Type — Selection — Enam- eling Ovens — Equipping Fuel Ovens for Electric Heat — Revolving Type Ovens — Drying Ovens — Heat Losses Through Oven Walls. CHAPTER XIII. Incubating and Brooding 185 Modern Methods — Poultry Incubating — Electric In- cubators — Advantages — Relative Operating Costs — Brooding of Chickens — Electric Brooders — Advan- tages — Relative Costs of Operation. CHAPTER XIV. Electric Welding 197 Nature of Welding — Processes — Arc Welding — Com- parative Costs — Resistance Welding — Welding Vari- ous Metals — Energy Requirements. CHAPTER XV. Electric Steam Boilers 214 Application — Advantages — Calculations — Efficien- cies — Energy Requirements — Steam Boiler Appar- atus. CHAPTER XVI. General Applications of Electric Heat 221 Diversity of Use — Automobile Heater — Bacteriolog- ical Incubators — Bath Cabinets — Beer Vat Dryers — Branding Irons — Button Die Heater — Can Capping — Candy Batch Warmer — Celluloid Embossers — Choc- olate Warmers — Corn-Popping Machines — ^Dryers of all kinds — Embossing Press Heaters — Engravers' Stoves — Flask Heaters — Gilding Wheel Heaters — Glove Stretchers — Glue-Pots — Hatters' Tools — Heat- ing Units — Hot Plates— Irons — Linotype Pots — Liquid Heaters — Meat Branders — Metal Melting — Number Brander — Oil Tempering Baths — Pallette Die Heaters — Paper Seal Moistenei* — Paper Warmers — . Peanut Roaster — Perforator — Pipe Thawer — Pitch Kettles — Shoe Machinery — Solder Pots and Irons — Sterilizers — Tire Vulcanizers — Water Stills — Weight Redvicer — Yarn Conditioner. CHAPTER XVII. Rates for Heating Service 258 Establishing of Rates — Heating Loads — Rate Makers' Difficulties— N. E. L. A. Rate Principles — Application to Heating Rates. Appendix 261 HEAT ENERGY AND ELECTRICITY 3 raise the temperature of one pound of any substance one degree Fahrenheit. A clear conception of the use of this unit of meas- urement is essential to the designer of heating appa- ratus, since it indicates the capacity for absorbing heat for a given temperature change. All the heat taken up in raising the temperature of a substance is given off when the body cools. The total heat absorbed by a body is equivalent to the product obtained by multi- plying temperature difference, weight, and specific heat. It will be noted from the table in the back of the book that the specific heat of water (i.e., its heat absorbing power) is greater than that of most known substances. Thermal Capacity. — The thermal capacity of a substance is the quantity of heat required to raise its temperature one degree. It is the product of its spe- cific heat and mass. As the specific heat of water is unity, fifteen pounds of water has a thermal capacity of 15 X 1 ^ 15 B.t.u. Likewise the specific heat of cast iron being .1298, fifteen pounds of iron has a thermal capacity of 15 X .1298= 1.947 B.t.u. The Calorie. — Heating calculations are frequently expressed in calories instead of British thermal units. The French thermal unit, or calorie, is that quantity of heat required to raise the temperature of one kilo- gramme of water one degree Centigrade. It is equiv- alent to 3.968 British thermal units ; or one British thermal units is equal to .252 calorie. Mechanical Equivalent of Heat. — Heat and me- chanical energy are mutually convertible. The num- ber of foot-pounds of medhanical energy equivalent to one British thermal unit is the mechanical equiv- alent of heat. It has been established experimentally that one B.t.u. is equal to 778 foot-pounds, and on that basis it has been calculated that one horsepower is equivalent to 2545 B.t.u. per hour. Relation to Electrical Units. — Where resistance is offered to the flow of an electric current the electric energy is converted into heat energy. The heat gen- 4 ELECTRIC HEATING erated is proportional to the resistance of the con- ductor, the square of the current strength, and the length of time the current flows. It has been estab- lished experimentally that one ampere of current flow- ing through a resistance of one ohm for one hour will generate 3.412 B.t.u.. Since one ampere flowing one hour through a resistance of one ohm is equivalent to one watt-hour, 3.412 B.t.u. equals one watt-hour (EIT=RrT) or 3412 B.t.u. equals one kilowatt hour. If it is desired to raise a certain quantity of a substance through a certain temperature range the number of kilowatt hours required for the operation may be calculated as follows : Degrees rise F. X Pounds X Specific Heat Kw-hr. = % Efficiency X 3412 Divide the number of kilowatt hours determined by the above calculations by the number of hours allowed for the operation and the result will be the kilowatts of heater capacity required far perform- ing the work. Latent Heat. — The quantity of heat which is ab- sorbed by a body in a given state in converting it into another state without changing its temperature is termed its latent heat. Latent heat of fusion is the heat absorbed in changing a body of a certain weight from a solid to a liquid without changing its temperature. When the operation is reversed the same quantity of heat is given oflf as was previously absorbed. Latent heat of evaporation is the heat required to change a unit weight of a solid or liquid at a given temperature into a gaseous state at the same temper- ature. It is the heat that disappears during the change and which will reappear if the operation is reversed. Whereas it requires only 180 B.t.u. at atmospheric pressure to heat a pound of water from the freezing to the boiling point (termed sensible heat), it re- quires 970 B.t.u. (latent heat of evaporation) to con- vert the same quantity of water into steam at 212 de- grees F. HEAT ENERGY AND ELECTRICITY 5 The total heat of evaporation is the sum of the sensible heat and the latent heat of evaporation. Radiation. — Heat passes from warm to cold bodies by three general methods, — radiation, conduction, and convection. Radiation of heat takes places between bodies at all distances apart and the heat rays pro- ceed in straight lines until intercepted or absorbed by some object. The amount of heat transmitted varies inversely as the square of the distance from the source. The rate at which heat is given off or absorbed depends upon the character of the surfaces of the bodies as well as upon their relative temperatures. Dark and rough surfaces radiate and absorb heat more readily than smooth and polished ones. Radiant heat passing through air or other gases does not affect their temperature to any appreciable extent. Conduction. — The transfer of heat between two bodies or parts of a body in direct contact with one another is termed conduction. It differs from radiant heat in that it does not necessarily travel in straight lines, and in its gradual rather than instantaneous transfer. The quantity of heat conducted is propor- tional to the cross sectional area, to the temperature difference, and to the character of the material. Metals are, in general, better conductors of heat than other materials, although they vary to a very great extent. The conducting power of stone is less than one per cent that of copper, and iron is about 3500 times as good a conductor as air. Convection. — The transfer and diffusion of heat in a fluid mass through the motion of the particles of the mass is termed the convection of heat. The parti- cles must be in constant motion in order to insure uni- form temperature of the mass. When the particles come into contact with hot bodies the mass will be warmed in proportion to the freedom of circulation in the fluid. Air is usually heated in a room by circulation of the air particles and bringing them into contact with heated surfaces. The better the circulation of air 6 ELECTRIC HEATING against these surfaces the more uniform will the room temperature become. Comparisons of Fuel and Electric Heat. — The rela- tive heating values of fuels are often compared with electric heat. For instance, it may be shown that with coal having a heating value of 14,000 B.t.u. per pound and costing $5 per ton, manufactured gas having a heat- ing value of 600 B.t.vi. per cu. ft. and costing $1 per thousand cu. ft. and electricity having a heating value of 3412 B.t.u. per kilowatt hour and costing one cent per kilowatt hour, one cent will buy 56,000 B.t.u. of coal heat, 6000 B.t.u. of gas heat, and 3412 B.t.u. of electric heat. However, the fact must not be over- looked that all fuel apparatus is naturally less efficient than electric apparatus. With average efficiencies of say 10 per cent for coal, 20 per cent for gas, and 70 per cent for electric apparatus, the purchasing power of one cent under the above assumed prices and heat- ing values would be 5600 B.t.u. of coal heat, 1200 B.t.u. of gas heat, and 2388 B.t.u. of electric heat. The following table will be of assistance in mak- ing hasty comparisons of the B.t.u. value of fuel and electric heat. Efficiencies lower than 50 per cent are seldom, if ever, encountered in electric applications and are therefore omitted from the table. B.t.ii. PiiFfhasIng Power of One Cent. Efficiency of Apparatus in <7^.: 100 75 50 30 20 10 14,000 B.t.u. Coal— $ 5.00 per ton 56,000 42,000 28,000 16,800 11,200 5,600 $10.00 per ton 28,000 21,000 14,000 8,400 5,600 2,800 600 B.t.u. Gas — $1.00 M. cu. ft 6,000 4,500 3,000 1,800 1,200 600 $1.50 M. cu. ft 4,500 3,375 2,250 1,350 900 450 Electricity — Ic per kw.-hr 3.412 2,559 1,706 2c per kw.-hr 1,706 1,279 853 3c per kw.-hr 1,137 853 568 5c per kw.-hr 682 512 341 Actual experience proves that many careful cal- culations do not work out in practice. One might as- sume from the above figures, for instance, that the cost of using a gas range would be at least five times as LAMP SOCKET HEATING DEVICES 9 in greater quantities than any other electrically heated device known. The principal advantages of the electric iron over the old fashioned sad iron are saving in time and steps, even heat distribution, freedom from smoke, grease and soot, absence of excessive heat, and ease w^ith which it may be used in any part of the house. Irons varying in weight from 3 pounds to 9 pounds and in capacities from 200 watts to 675 watts are avail- able for domestic use. Electric Stoves. — Both the disc and open coil type are manufactured in various sizes and capacities. The disc stove has a metallic heating surface and delivers G. E. Twin Plate Disc Stove. heat to the utensil by conduction. The open coil stove gives off radiant heat from exposed coils which are usually imbedded in grooves of porcelain or mounted above metallic reflectors. Electric stoves are useful for many household pur- poses in place of gas or alcohol burners. They are suitable for heating water for various purposes, or for doing light cooking. They are safe, convenient and durable. For domestic lamp socket use they are sel- dom larger than six inches in diameter and 600 watts in capacity. Toaster Stoves. — Two distinct types are made — horizontal and vertical. Toast made on the horizontal type will be produced quickly but will not be toasted through so well unless the bread be dry. Toast made below radiant coils or in the vertical type toasters will be produced slowly but will be toasted thoroughly. Vertical toasters are usually provided with a warm- ing shelf on top to keep toast or other food warm. 10 ELECTRIC HEATING Westinghouse Horizontal Toaster Stove. One great advantage of electric toasters is that they may be used on the dining room table instead of in the kitchen. From 400 to 600 watts are usually required for operating toasters. Hot Point Vertical Toaster. Chafing Dishes. — These frequently have an outer pan in addition to the food pan for use as double boil- ers. The food pans are made in two and three-pint sizes. The capacities vary from 250 to 600 watts. A wide variety of styles and ornamental types are avail- able. Electric chafing dishes are obviously safer to op- erate than alcohol or other flame types, and further- more they give oflf no disagreeable odors or fumes. LAMP SOCKET HEATING DEVICES 11 Universal Chafing Dish. Coffee Percolators. — Coffee made in an electric percolator is rich in flavor, free from grounds, and contains less caffein and other harmful elements than boiled coffee. Starting with cold water, strong coffee may be prepared in from ten to fifteen minutes. Hot Point Percolator, Electric percolators in all styles, shapes and char- acter of ornamentation and in sizes varying from four to nine cups are available. They usually require from 450 to 600 watts. They are ideal for use on the dining 12 ELECTRIC HEATING room table because they are attractive in appearance and also keep the coffee hot with practically no atten- tion. Tea Samovars. — The housewife who prides herself on her tea-making is pleased with a device where the tea-ball may be drawn up when the infusion is just right and a beverage served of fine flavor, and free from the bitter tannic acid taste that results from 1)oiling tea-leaves in an ordinary pot. It is especially desirable for the afternoon tea because it can be oper- ated in the living room. It furthermore does away with the disagreeable odors, fumes and dangers of alcohol or other fuel types. Tea samovars are usually made in 5, 6 and 7 cup sizes and in capacities varying from 400 to 500 v/atts. Tea Kettles. — Two and three pint sizes are usually made, requiring from 400 to 550 watts for operation. They are convenient and dainty for heating water for the tea service. They make an attractive addition to the table and possess the charm of a modern household luxury. Simplex Dining Room Set. Table Cooking Outfits. — Single disc stoves sup- plied with a variety of hollow-ware utensils are called unit-sets, dining room sets or combination stoves. Cof- fee percolators, tea samovars, chafing dishes, nursery milk warmers, frying pans, tea kettles, griddle plates, and other utensils are included in the various sets. These devices bring electric cookery within reach of every one and encourage a better understanding of LAMP SOCKET HEATING DEVICES 13 its cleanliness, and convenience. For the hostess who does her own cooking the table cooking outfits are ideal. They are an ornament to any sideboard or table. Electric Grills. — Many handy devices for cooking on the dining room table, or in the sick room, and which are attractive and convenient, are made by various heating appliance manufacturers. The Hotpoint El Grillo is a useful table device. It may %^ Hot Point Grill Stove. be used for light toasting, frying and broiling as well as for boiling. Two of these operations may be carried on at one time as the utensils may be placed both above and below the glowing coils. It has a capacity of 600 watts and the dimensions of the heating element and pans are 4^4 by 8^ inches. The Westinghouse toaster stove is really a small complete cook stove. It may be used for broiling, frying, toasting, boiling or making griddle cakes. The stove is 5% by 9 by 3^ in. high and consumes 500 watts. The General Electric radiant grill may be used for frying, stewing, toasting, and broiling. This device consumes 600 watts. Food Warmers. — Eood warmers are made in a variety of portable styles, shapes, and sizes, and may be used on the table or sideboard. Simplex nickel or silver plated food warmers of the following sizes and capacities are available : Oval shape, 10 in. by 14 in 170 watts Oblong shape, 10 in. by 14 in 200 10 in by 18 in 250 Oblong- shape (extra heavy) 10 in. by 14 in 200 10 in. by 18 in 250 10 in. by 26 in 400 14 ELECTRIC HEATING Simplex Food Warmer. Plate Warmers and Hot Closets. — A variety of shapes and sizes of plate warmers and hot closets are manufactured to order to fit available spaces, or stand- ard portable types may be used. Hughes Plate Warmer In estimating- the size of a plate warmer closet a shelf space of at least 10>^ in. should be allowed for ordinary dinner plates and a height of 6 in. for twelve in a pile. On account of the relatively low temperature re- quired inside the oven, the current consumption is usually low, especially if the walls are well insulated against heat losses. Bake Ovens. — Devices like the small Hotpoint lamp socket bake ovens (El Bakos) are useful for light LAMP SOCKET HEATING DEVICES 15 baking operations. The inside dimensions are 11 in. by 10y2 in. by 7y2 in. and they consume 600 watts on the high heat. They are of steel construction with nickel Hot Point El Bako. trimmings and the walls are lined with mineral wool to retain the heat. These ovens have practically all the inherent advantages of larger electric ovens. Simplex Nursery Milk Warmer. Nursery Milk Warmers. — These consist of a water vessel and cover, a milk bottle, and a nipple. They are designed for quick heating and are made in capacities varying from 300 to 500 watts. They are ready for use at any time — day or night. The 500 watt size 16 ELECTRIC HEATING will heat a bottle of milk in about four minutes or boil a pint of water in about six minutes. Curling Iron Heaters. — These are desirable on ac- count of their absolute cleanliness, convenience, and safety. They are made in capacities varying from Universal Curling Iron and Hair Dryer. 60 to 90 watts and in plain or ornamental types. The Westinghouse electric curling iron is equipped with a heating element inside the iron which consumes 15 watts. Warming Pads. — For local applications of heat to the body electric pads are rapidly superseding the hot water bottle and similar devices. These pads are Simplex Warming Pad. usually made of soft padded cloth although some of the new Hotpoint pads are made of either rigid or flexible metallic materials. The Westinghouse pads are 11 in. by 15 in. and have an outer rubber cover. The Simplex pads have an eiderdown cover and are made in two sizes, 12 in. by 15 in. and 15 in. by 24 in. LAMP SOCKET HEATING DEVICES 17 The American warming pad is 12 in. by 13 in. Warm- ing pads are generally provided with regulating switches giving three degrees of heat. The capacities vary according to dimensions from 50 to 100 watts maximum. The American sweating blanket is 5 ft. long by 18 in. wide and requires 800 watts. Immersion Heaters. — These appliances are useful in the home that is not provided with a constant supply of hot water. By fastening to the lamp socket and sub- merging the heater in water or other liquid the sub- Hot Point Immersion Heateis. Stance can be brought to a boil very quickly. Inas- much as the heating element is placed directly in the liquid the efficiency of operation is high. They are handy for shaving and similar purposes. Heaters of various shapes and capacities are available. Other Household Devices. — A few of the better known heating and cooking devices are mentioned for reference purposes. Egg boilers are convenient because they can be used on the table and given personal supervision. Fry pans and saute pans designed for use on the dining room table are useful. Soup tureens are handy for keeping soups and other prepared foods at the proper temperature for serving. 18 ELECTRIC HEATING The Hotpoint utility outfit which comprises a three pound iron provided with a stand on which it may be inverted for cooking, and a receptacle for in- serting a curling iron is useful for the roomer or trav- eler. The foot warmer is a handy device for use in rooms with cold floors. If placed under a desk or Universal Egg Cooker table it will keep an occupant warm even when the room is comparatively cold. Air radiators of both the radiant and convection types are useful in small rooms and in cold corners. A separate chapter is, however, devoted to the sub- ject of air heating. CHAPTER III INSTALLATION OF HEATING APPARATUS. Correct Installation. — This is essential for ranges, water heaters, and other heating devices. If wires are too small, the service will be poor. If the appearance of the work is not good, the user will be dissatisfied. If proper protection against electric shocks is not aflForded, the customer may be in constant fear. If a range, for instance, is not placed in such a position that it can be conveniently operated by the cook or housewife, she may form mental prejudices that will be difficult to overcome. Intelligent supervision and caretul inspection of all heating installations will be of mutual benefit to all concerned. Wiring for Heating Apparatus. — The Code of the National Board of Fire Underwriters should be adhered to as closely as possible in wiring for heating apparatus. Furthermore, local city and state rulings have a distinct legal status the importance of which should not be overlooked. Unfortunately the National Code rulings which apply to the installation of heat- ing service are in some cases burdensome, and in others not strict enough. All wiring should be done in a neat and work- manlike manner so that an electric installation will not detract in any way from the appearance of the prem- ises. Electric ranges, water heaters, and other heat- ing devices on the market usually look attractive, but if they are not properly connected and installed the general appearance may be bad. Carrying Capacities of Wires. — The allowable car- rying capacity of conductors operating under pres- sures of 120 volts, two-wire, and 120-240 volts, three- wire, are given in Table I for convenient reference 20 ELECTRIC HEATING Table I. Maximum Allowable Wattage Carrying Capacity. Size Area — Rubber Covered — — Weather Proof— B. &S. Circ. 120 volt. 120-240 V. 120 volt 120-240 V. Gauge. Mils. 2-wire. 3-wire. 2-wire. 3-wire. 0000 211,600 27,000 54.000 39,000 78,000 000 167,800 21,000 42,000 33,000 66,000 00 133,100 18,000 36,000 27,000 54.000 105,500 15,000 30,000 24,000 48,000 1 83,690 12,000 24,000 18,000 36,000 2 66,370 10,800 21,600 15,000 30,000 4 41,740 8,400 16,800 10,800 21,600 6 26,250 6,000 12,000 8,400 16.800 8 16,500 4,200 8,400 6,000 12.000 10 10,380 3,000 6,000 3,600 7,200 12 6,530 2,400 4,800 3,000 6,000 Wires of sufficient size to conform to the allow- able carrying capacities in the above table will conform to the Underwriters' Code but may prove too small to insure good service. This will be true if the run is a long one because in the above table no account is taken of its length. Table II shows the drop in voltage (below 120) that may be figured per hundred feet of both two and three-wire circuits. The calculations are based on an assumed pressure of 120 volts for two-wire service and 120-240 volts impressed on a three-wire circuit. Table II. Wattage Load on End of Line. No. 2500 5000 7500 B. &S. 2- 3- 2- 3- 2- 3- Gauge wire. wire. wire. wire. wire. wire. OiQCO .204 .102 .409 .204 .619 .306 000 .258 .129 .515 .258 .774 .386 00 .325 .162 .650 .325 .975 .487 .410 .205 .819 .410 1.229 .615 1 .517 .258 1.033 .417 1.550 .775 2 .651 .326 1.303 .651 1.954 .977 4 1.036 .518 2.071 1.036 3.107 1.553 6 1.647 .824 3.294 1.647 4.941 2.471 8 2.618 1.309 5.237 2.618 7.855 3.927 10 4.164 2.082 8.329 4.164 6.246 12 6.623 3.312 6.623 9.935 No. 10,000 15,000 25,000 B. &S. 2- 3- 2- 3- 2- 3- Gauge wire. wire. wire. wire. wlre. wire. 0000 .818- .409 1.238 .619 2.044 1.022 000 1.03i0 .515 1.548 .774 2.576 1.288 00 1.200 .650 1.950 .975 3.250 1.625 1.638 .819 2.458 1.229 4.096 2.048 1 2.066 1.033 3.100 1.550 5.166 2.582 2 2.606 1.303 3.908 1.954 6.515 3.257 4 4.143 2.071 6.214 3.107 5.178 6 6.588 3.294 9.882 4.941 8.235 8 5.237 7.855 .... 10 8.329 .... 12 .... .... INSTALLATION OF HEATING APPARATUS 21 Correct Voltage. — For heating apparatus this is important. Many complaints may be obviated by sup- plying energy at a pressure as near as possible to the rated voltage of the apparatus. Low voltage results in slowness of operation, and excessively high volt- age is likely to cause burn outs. Assume a heating element rated at 1100 watts and 110 volts is supplied with energy at a pressure of 100 volts. The resistance of the element is therefore: R =E/I = 110/10=11 ohms. At 100 volts pressure the quantity of current flow- ing would be I ^ E/R ^ 110/11 ^ 9.1 amperes and the wattage dissipated in heat would be W = EI = 9.1X100^910 watts. The efficiency of operation of the element, therefore, would be 910/1100 = 82.7 per cent, whereas the voltage was supplied at only 100/110 = 91 per cent of the normal rating. Voltage readings should always be made at the terminals of the heating device at no load and at full load, otherwise the drop in voltage in the service leads or interior wiring may be overlooked, and a wrong impression gained. Methods of Wiring. — How to wire a building for heating service should be carefully considered before the actual work is undertaken. Exposed wiring with knobs and cleats is safe and cheap but is seldom used because of its unsightliness. Moulding work is some- times installed in old buildings but unless the work is done extremely well it may look unattractive. The concealed knob and tube method is often used in both new and old buildings and the work may usually be done at reasonable cost. Rigid or flexible conduit, or steel armored conductor wiring are generally consid- ered to be the best, although the most expensive methods. Exposed Knob and Cleat Wiring. — This is often used in wiring for heating and cooking service and in places where appearance is of little consequence it is one of the cheapest and best. The wires may be single braid rubber-covered or slow burning weather-proof. 22 ELECTRIC HEATING In cellars or other places exposed to moisture rubber- covered wire must be used. Wooden Moulding Wiring. — Where a neat ap- pearing low-priced job is required this construction may well be used. Its use in damp places is however prohibited by the Underwriters. Single braid rubber- covered wire is required. For first class work hard wood moulding, matching in finish the trim of the room, can be used. Wiring in Metal Moulding. — As this is restricted to circuits carrying not more than 1320 watts it is seldom employed for heating or cooking circuits. Single braid rubber-covered wire may be used for this class of work. Metal moulding must always be grounded permanently. Concealed Knob and Tube Wiring. — In frame buildings where a low cost of installation is essential the wires may be installed within floors and partitions. Wires can ordinarily be concealed in this manner more cheaply than by any other method. Single braid rubber-covered wire may be used. Rigid Iron Conduit. — This is approved for both exposed and concealed work. Ordinarily it is prob- ably the best, although the most expensive. Double braid, rubber-covered wire must be used in rigid conduit. The same conduit may contain as many as 4 two-wire or 3 three-wire circuits. Stranded wire in sizes larger than No. 6 is customarily used for rigid conduit work. Rigid conduit must be permanently grounded. Table III. Size of Size of Conduit, Inches. Wire. Two Wires in Conduit. Three Wires in Conduit. B. &S. Short Medium Long- Short Medium Long Gauge. Run. Run. Run. Run. Run. Run. 10 V2 % % % 1 1 8 % % 1 1 IV4 ly* 6 1 1 1^ 1 iy4 1% 4 1 1% 1^ IV4 iy4 1V2 2 1% 1% 1% 1% 1V2 2 1 IV* 1% ' 2 IV2. 2 2 1% 2 2 2 2 2 00 1% 2 2 2 2 2y2 000 2 2 2 2 2y2 2y2 0000 2 2 2% 2 2y2 3 INSTALLATION OF HEATING APPARATUS 23 Table III shows the size of double braid rub- ber-covered wires that can readily be pulled into con- duit. Flexible Metallic Conduit. — For all kinds of ex- posed or concealed work such construction is often preferable to rigid conduit. The installation of flexible conduit can be made easier, quicker, and more cheapl}^ than can riged conduit. The same code rules apply to flexible as to rigid conduit. It must be securely grounded. Double braid rubber covered wire is re- quired. Flexible metallic conduit may be used to ad- vantage in finished houses and in frame buildings. The sizes of wire that may be accommodated in flexible steel conduits are given in table IV. Nominal Table IV. aside Diam. Largest Wires Accomm( adated. In Inches. o ne Wire. Two W ires. Three Wires. y2 % 1 ly* IVs 2 8 2 00 200,000 400,000 800,000 12 10 4 1 200,000 12 8 6 3 00 Flexible Steel Armored Conductor. — Here a cable consisting of rubber-covered wires is protected from injury and to a certain extent from dampness by two layers of flexible steel armor. It may be obtained leaded or unleaded. The leaded cable diflfers from the unleaded in that it has a lead covering between the wire and the steel armor to protect it from excessive damp- ness. Both the leaded and the unleaded cables are made with single and multiple conductors of almost any gauge wire. The leaded cable is approved for all classes of work, open or concealed, in fireproof or non- fireproof buildings, and in new or old houses. The un- leaded cable is approved and may be used for open or concealed work in places not subject to moisture. For wiring old buildings steel armored con- ductor can be used to great advantage. It can be run with utter disregard to contact with pipes or other materials and may be fished for long distances. It can be installed quicker and with less cutting away of the walls and floors than either rigid conduit, flex- 24 ELECTRIC HEATING ible tubing, or concealed knob and tube work. Steel armored conductor should always be carefully grounded. The Main Entrance Switch. — For three-wire heat- ing circuits this should always be of the fused type with the neutral fuse coppered. Control Switch. — Heating devices should be pro- vided with control switches that will indicate at a glance whether the circuit is open or closed. The switch should be mounted on the device or on the wall imme- diately adjacent to it so as to be easily accessible. It should be of the enclosed knife blade or snap switch type and so designed as to entirely disconnect the heat- type appliance at the wish of the operator. Grounding. — The frames of all heating appliances, especially those of the larger types, should be carefully grounded, whether they are connected to two-wire or three-wire circuits. Satisfactory grounding may be accomplished by connecting the frame of the device to a water pipe. If the appliance is operated from a three- wire grounded neutral system the frame may be con- nected to the neutral wire. In case of doubt as to the character of the ground on such a system, the neutral may be grounded, in turn, to some convenient water pipe inside the building. When a rigid or flexible metallic conduit or steel armored conductor job is installed, the frame of the device may be grounded to the conduit or steel armor ; provided, of course, the conduit or armor is itself grounded elsewhere. Ranges in Apartment Houses and Flats. — In this case separate circuits from the main switchboard are necessary. Each circuit must be fused but in the case of three-wire circuits the neutral should be coppered. Main service wires and switches supplying group cooking loads are never called upon to carry the entire connected load. Apartment houses equipped with ten or more ranges are never known to have a demand greater than one-fourth the connected load. The larger the number of ranges supplied from a single INSTALLATION OF HEATING APPARATUS 25 service the less will be the demand in proportion to the load connected. This is a condition seldom met with in supplying other classes of electric service and one for which no provision has been made in the Un- derwriters' Code. It is obvious, however, that to install service leads, main switches, fuses, etc., of sufficient carrying capacity to handle the total con- nected load would be of no advantage, and would in- volve needless expense. The Proper Position for a Range. — The range should be located where it can be operated with ease and conven- ience. If it is placed where the light is bad, in an inac- cessible corner of the kitchen, or where the cook or housewife has to walk back and forth a greater distance than that to which she has been accustomed, a serious prejudice may be created in her mind. An electric range is often installed in a kitchen by the side of a coal, gas, wood, or oil range, the latter being left in, either for auxiliary use or for want of a better place for storing the old equipment. When this con- dition is met, every endeavor should be made to secure permission to place the electric range in the most advantageous position. Otherwise the customer will have a tendency to use the appliance most favorably located for most of her work. CHAPTER IV ELECTRIC COOKING. The March of Progress. — Modern civilization's ad- vance may be clearly indicated by the progress in methods of cooking. Wood was the first material to be used as a fuel. Water was boiled in a kettle sus- pended over a log fire and meats were broiled on a spit, or roasted in the embers, for many hundreds of years. When it was found that coal produced a more uniform and hotter fire, and was far more desirable than wood, another era of progress was marked. The old fashioned fire place gave way to the more modern kitchen range. Then came fuel gas, which may be considered a product of coal, and the gas stove made its appearance. Although the use of gas obviously in- volved more danger and was somewhat more expen- sive, it was found to be quicker and far more con- venient. Crowning success was achieved, however, when the electric method was perfected, and the bridging of space between the historic fuel fire and the modern heat produced without flame was accomplished. Advantages of Electric Cooking. — The extent of the improvement brought about by the electric range is almost unbelievable. The heat is under absolute control. The operator knows and commands the tem- perature at all times. The wasting of heat has been reduced to a minimum. The units or burners generate the heat right where it is used, and very little loss takes place. The heat utilized in the oven is generated on the inside, and as its walls are heavily insulated with material of low thermal conductivity, there is prac- tically no opportunity for useful energy to escape. Facility of Operation. — The electric range is easier to operate and can be regulated with a much greater degree of accuracy and certainty than the fuel range. ELECTRIC COOK] 27 Being clean, safe and labor-saving, its use promotes greater cleanliness and comfort. It produces no excess heat, smoke or fumes to vitiate the atmosphere, and does away with the constant attention and anxiety of the fuel fire. Cooking utensils, furthermore, may always be kept clean and free from smoke and soot on both the inside and outside. Hughes No. 60 Range (for Large FamUy Use). Uniformity is attained in the electric range be- cause it will always produce the same results under the same operating conditions. For instance, the oven has to be opened but twice for each operation — once when the food is inserted, and again when the cooking is completed. The operator has only to watch the clock while the food is cooking. This advantage par- tially removes the objection that many persons have to a low oven, which, with fuel stoves, requires con- stant bending over to examine the condition of the 28 ELECTRIC HEATING food. Any housewife, of even moderate intelligence, should be able to master the essential features of the operation of an electric range in a short time by simply reading the card of instructions that is sent out by the manufacturers with each range. Special Advantages. — The individual operations in which the electric range outclasses every known type of fuel stove, are baking, roasting and broiling. The heat being uniformly distributed in all parts of the oven, insures even baking and browning. It will bake bread, cake, and pies that are most attractive in ap- pearance. They will always have just the right color, will contain more nourishment, and remain fresh longer. Roasts should always be prepared in an open pan containing no moisture, and basting is unnecessary in the electric oven. Sufficient moisture and meat greases will collect in the pan during the operation to prevent burning, and to provide material for gravy. The roast itself will come out of the oven uniformly browned on top, bottom and sides, if no basting is done. In both roasting and broiling operations the meat is seared, thereby retaining its natural juices, and mak- ing it more delicious, nutritious and attractive to serve. Reduction in Meat Shrinkage. — Many experiments have been made in actual practice to show that there is less shrinkage in meats prepared electrically than by any other means. The meats sear over as soon as placed in the oven ; there is no burning away of the fats and juices; and a saving of from 15 per cent to 18 per cent in the actual weights of the meats is efifected. The tremendous economy in household ex- pense that is made possible by the use of the electric range is apparent if we consider a family whose meat bill has averaged $15 per month and a saving made of 15 per cent in the meat shrinkage by the use of elec- tricity. Meat costs in this family would be reduced $2.25 per month with the exercise of no additional self denial. Assume an eight pound roast is placed in a 1600 watt electric oven and roasted IVi hours. The current ELECTRIC COOKING 29 consumption at high heat would be 4 kilowatt hours, but by proper manipulation of the oven switch not over half this amount, or 2 kilowatt hours, would be actually consumed. The saving in weight of the meat over gas or coal cooking would amount to at least one pound. With current costing three cents per kilo- watt hour and meat twenty cents per pound the actual saving to the housewife in cooking the roast electrically would be as follows : 1 lb. of meat saved at 20c $ .20 2 kw -hr. at 3c cost 06 Actual saving $0.14 Model G Hot Point Range. Simplex 5-K Range. Important to Use Proper Utensils. — Only flat bot- tomed utensils should be used for surface cooking on the electric range. Air is a poor conductor of heat, and consequently, the closer the heating unit can be brought to the bottom of the utensil, the greater will be the efficiency of operation. The necessity is par- ticularly apparent in ranges making use of an element of the enclosed type, where the heat is transmitted to the food from a hot surface through the bottom of a utensil. If direct metallic contact is not secured the efficiency will be tremendously impaired ; slow opera- tion will result ; and the housewife will become dis- pleased. Agate or enameled ware should never be used on enclosed type elements. Iron, copper, or aluminum 30 ELECTRIC HEATING vessels will be found far more efficient. On the other hand, agate, enameled ware, and black bottomed iron utensils have been found very satisfactory for use with open type elements. Polished metallic bottom sur- faces reflect and do not take up the heat from a ra- diant type element as do black surfaces. Contrary- wise, highly polished sides and tops retain heat in a utensil much more efficiently than do dark or rough surfaces. If the bottom of any kind of utensil is cor- rugated, hollowed out or warped it cannot be ex- pected to give satisfactory results. Economy in Range Operation. — Food prepared on the cooking surface will not burn on the inside of the utensil as long as any moisture remains in the ves- sel, because heat is applied only at the bottom and never at the sides. For this reason, the amount of water usually required to keep food from burning may be reduced and the operations performed more easily and quickty. The food will be steamed thoroughly, and the natural sweetness and flavor will be cooked into the food, rather than boiled out into the water poured away. Water absorbs more heat than any commonly known substance, and a little economy in the use of water will effect considerable saving in both heat and electricity. Users of electric ranges should be encouraged to use water drawn from the hot water storage supply for cooking purposes. Water taken from the top of a tank is obviously purer than that taken from the water mains because the tank acts as a natural settling basin for the collection of all impurities and sediment. If hot water is used in preparing foods, the operations may be done more quickly, and considerable saving in current consumption effected. One very common method of effecting economies in the operation of a range, is to place as many foods as possible in the oven instead of on the cooking sur- face. The oven, being heavily insulated, retains prac- tically all the heat generated and the usual losses that attend cooking on the surface units are thereby done away with. ELECTRIC COOKING 31 Water for laundry work, washing, bathing, and other domestic purposes cannot be heated as econom- ically on an electric range surface as by other means. If the housewife desires, however, she may success- fully boil clothes by placing an ordinary copper bot- Hughes Junior Range (for Early Training of Housewife). tom boiler over two of the range discs. Quicker ac- tion will result if the boiler is kept covered, and a heavy paper wrapped about the sides of the vessel. The saving that may be effected by skilful use of the individual three-heat switches is often little under- stood by the average woman. She should be trained to know that the low heat consumes but one-quarter, and the medium heat one-half as much current, as the high heat. Food brought to the boiling point on high heat should be retained at this temperature at 32 ELECTRIC HEATING low or medium heat. A boiling temperature higher than 212 degrees F. cannot be obtained in an open vessel and food will cook just as quickly when boiling slowly as when boiling rapidly. Elimination of Kitchen Chimneys. — If fuel is burned in a kitchen a chimney is naturally required. On the other hand the expense of installing a chimney may be obviated by using an electric range. Even with gas the harmful products of combustion must be removed as shown by the following from page 20, Technical Paper 109, U. S. Bureau of Mines : "Natural gas, when burned with sufficient oxygen for complete combustion, forms carbon dioxide and water vapor. Each cubic foot of natural gas burned produces a little over 1 cubic foot of carbon dioxide and a little more than 2 cubic feet of water vapor. Carbon dioxide is an irrespirable gas and should not be allowed to accumulate in a room. Water vapor also should be removed, because it has a depressing effect if present in still, warm air in sufficient proportion and tends to make the walls, ceilings, curtains and other objects in a room dirty because the dust is entrained iby it and settles on the objects." "The only way to remove these two gases is by means of a vent leading from the stove to the house chimney. It is absurd for any manufacturer of stoves to claim that these two gases are practically absorbed or eliminated in any other way." Operation by Servants. — Care should be exercised in placing a range in the hands of a professional cook. This type of individual is frequently a difficult person to handle. He seldom favors anything new. He is prone to form intense prejudices; and will often re- fuse to make an intelligent investigation of new appa- ratus, especially when he has not been previously con- sulted. He is always a very powerful factor in matters concerning the management of a kitchen, and his posi- tion should not be overlooked. If he dislikes equipment placed in his charge he may damage it, refuse to handle it properly, or cause the operating cost to run up excessively. Disastrous results are certain to accrue if the cook's attitude is unfavorable. ELECTRIC COOKING 33 Repeated experience has proved that the house- wife who does her own cooking is the most desirable user of an electric range. She will be, as a rule, thor- oughly alive to its advantages, will practice the many little economies that are possible, and will generally become a "booster" for electric cooking. Attention to Range Users. — When ranges are first installed the users should receive very careful atten- tion. It must be remembered that the manipulation General Electric No. S-3 Range. of an electric range is entirely new to the average housewife. If something about the apparatus is out of order; if the best results are not secured at the start ; or if some of the many little economies that may be practiced are overlooked and the first month's bill proves higher than has been anticipated, an erroneous mental impression may be formed that may prove dif- ficult to correct. If troubles are not rectified or ex- plained away, they will become magnified as time passes, and the housewife may finally become seri- ously prejudiced. Furthermore, every electric range placed is naturally watched by the many friends, rel- atives and neighbors of the user. In as much as it is generally conceded that the best advertising medium 34 ELECTRIC HEATING is the satisfied customer, it is well worth while to give the user early and painstaking attention. Electric Cooking in Schools. — The encouragement of electric cooking in the domestic departments of ed- ucational institutions will foster the more rapid intro- duction of electric ranges in the homes. In order that correct impressions may be created in the minds of the students, it is highly important that the equipment be intelligently selected, that the apparatus be properly installed, and that the service be the best attainable. Domestic Science Classroom, Westminster College, Salt Lake City. For classroom work, small rather than large in- dividual disc stoves should be installed, because only a small amount of food need be prepared at one time. Double boilers and frying pans should be provided with each stove, and these utensils should be of a size to fit and of a kind that w^ill operate properly with the particular type of disc stove that is installed. Small individual bake ovens are comparatively inexpensive, occupy little space, produce excellent results, and may be recommended for well-equipped departments. In some school where domestic science is taught complete electric cooking equipments have been pro- vided and meals prepared and served cafeteria style during the noon hour periods. The income from the ELECTRIC COOKING 35 iioininal charge made for these meals has been ade- quate, in a number of instances, to pay the operating^ cost of the electric kitchen, as well as of the entire department. Other institutions have gone further, and arranged for the use of electric flat irons, water heaters, and other labor-saving devices. At least one complete elec- tric range should be made the part of any modern domestic science room equipment. The comparatively few hours during which classes are in session make the operating cost of electrically operated installations very small. Although the income from this class of McDonald Apartments, Boston, Equipped with Hughes Ranges. business is not large, the load is of an oiT-peak char- acter, and the results are far-reaching. The favorable impression created by equipping domestic science de- partments in this manner cannot but have a beneficial efifect upon the school and a credit to the individuals in charge. Electric Cooking in Apartment Houses. Adaptability of Electric Range. — The electric range seems to be peculiarly adapted for use in apart- ment houses. The character of construction of the buildings, the mode of living of the tenants, and the many recognized advantages of the electric range make it much superior to the fuel burning stove. A resume of the most essential qualifications of this type of appa- ratus and the better conditions that may be brought about where it is installed for apartment house cooking service should not be out of place in these pages. 36 ELECTRIC HEATING Jensen ApartmL nts. Gieat Falls, Mont. Simplex Ranges.) (Equipped with Economy in Space. — In the design of the modern apartment house every foot of space is valuable and the architect must plan to utilize it to the best ad- vantage. His efforts in this direction seem to ha\'e resulted in the laying out of very small kitchens which are often stufTy and poorly ventilated. The electric range is best fitted to meet these recognized conditions for several reasons : It is compact in construction, and as the exterior never becomes hot enough to burn the woodwork it may be placed against the wall and there- by take up less space. The unbearable heat of a fuel range in a small kitchen is eliminated. There is no combustion in the electric range and it neither throws off poisonous fumes nor takes up the life-giving oxygen from the air. Expense Saved. — The initial outlay required for the installation of chimneys and gas plumbing may be entirely eliminated. When the building is once occu- pied the periodical expenditures incident to repainting, retinting and repapering, may be cut in half. The very nature of the electric range, which creates no products of combustion, and which overcomes the ELECTRIC COOKING 37 smoke, moisture and grease nuisances peculiar to the fuel range, makes the frequent refinishing of interiors unnecessary. Elimination of Hazard. — Where fuel stoves are used there is constant danger of fire. Gas offers the menace of asphyxiation and explosion. The careless opening of a valve, a temporary cut-off of the main supply, or a little mistake of the cook or housewife may .|n::i::::H:|:;:||i;i:.j:.d.H|^::|n:j!H: i H::|^^^ Typical Apartment House Cooking- Load Curve, 24 Ranges, 75 kw. Connected, Maximum Demand 11% kw. result disastrously. In as much as the electric range produces no flame, and neither utilizes nor gives off any explosive or poisonous gas, its use does away with all danger of loss of life or property. Convenient for the Tenant. — On account of the ab- sence of soot and burned foods, the utensils used on an electric range are easier to cleanse both inside and outside. Silverware in an apartment house never tar- nishes as it does where gas is used. Unlike gas, elec- tricity throws off no sulphur fumes. Another condition that goes to make the electric range popular, is that an auxiliary supply of hot water is usually available for use in the apartment house, and may be utilized for cooking operations to attain quick results. 38 ELECTRIC HEATING Desirable Central Station Load. — I^>om an oper- ating standpoint the apartment house business is very desirable for the central station company. The load is, for the most part, of an off-peak character. The load factor and diversity factor are both unusually at- tractive. The maximum demand is frequently shown to be not over one-sixth of the connected load. Com- pared with apartment house lighting and elevator loads the business is obviously more desirable. Preparation of Food. Knowledge of Cooking Valuable. — For those inter- ested in the sale of electric ranges or in the building up of electric cooking loads, a general understanding of how foods are prepared, why it is necessary to cook them, and the best methods' to employ, will be of value. If one endeavors to interest a housewife in an elec- tric range, he should know something about the use to which it is to be applied, otherwise he will not read- ily gain her confidence. Anyone familiar with the fol- lowing paragraphs as well as with the natural advan- tages of electric heat, will be able to show the average housewife wherein electricity is superior to fuel heat in performing the various cooking operations sug- gested. Reason for Cooking. — The cooking of food has much to do with its nutritive value. Many articles which are quite unfit for nourishment when raw are nutritious when cooked. It is also a matter of com- mon experience that a well cooked food is wholesome and appetizing, whereas the same material badly cooked may be both unhealthful and unpalatable. Purposes gf Cooking. — There are three chief pur- poses of cooking. The first is to change the mechan- ical condition so that the digestive juices can act upon the food more freely. The second is to make it more appetizing by improving the appearance or flavor, or both. Food which is attractive to the taste quickens the flow of saliva and other digestive juices, and thus aids digestion. The third is to kill any disease germs, parasites, or other dangerous organisms it may con- ELECTRIC COOKING 39 tain. This is often an important object, and applies to both animal and vegetable foods. Cooking of Meats. — For the most part meat is either boiled, stewed, fried, broiled or roasted. In general, it is probably true that cooking diminishes the ease of digestion of most meats. It may also remove considerable quantities of the nutrients. Boiling of Meat. — If it is desired to heat the meat enough to kill bacteria in the inner portions of the cut, the piece must be exposed to the action of heat for a long time. If it is brought slowly to a boil, a good broth will be obtained, but the meat will be tough and tasteless. If a piece of meat is plunged into boiling water or very hot fat, the albumen on the entire surface of the meat is quickly coagulated and the crust thus formed resists the dissolving action of water and prevents the escape of the juices and flavoring matters. Thus cooked, the meat will possess the desired meaty taste but the resulting broth will not be considered good. It is impossible to make a rich broth and have a juicy highly flavored piece of meat at the same time. If the meat alone is to be used, it should be plunged into boiling water and kept at that temperature for about ten minutes, after which the cooking should be continued at about 180 degrees F. until the tissues become tender. Stewing of Meat. — If both the broth and the meat are to be used, the process of cooking should be quite dififerent from that of boiling. In stewing, the meat should be cut into small pieces so as to present rela- tively large surface area and, instead of being quickly plunged into hot water, should be put into cold water, in order that the juices and flavoring materials may be dissolved. The temperature should then be slowly raised until it reaches about 180 degrees F. where it should be kept for several hours. Treated in this way the broth will be rich, and the meat tender and juicy. Roasting of Meat. — The principle difiference be- tween roasting and boiling, is in the medium in which the meat is cooked. In boiling the flesh is surrounded 40 EL.ECTRIC HEATING by hot water, whereas in roasting it is surrounded by hot air and acted upon to some extent by radiant heat. In both operations, if properly conducted, the meat fibers are cooked in their own juices. When the meat only is to be eaten, either roast- ing, broiling, or frying in deep fat is a more rational method than boiling, for the juices are largely con- served in the meat. Cooking of Vegetables. — Vegetables baked, roasted, fried or boiled, are used for preparing a large variety of dishes. The most common method of cooking is that of boiling in water. The steaming of vegetables is often resorted to, but the results are similar to those of the boiling process. The simpler the method of cooking and serving vegetables the better. A properly cooked vegetable will be palatable and readily digestible. Poorly cooked, water soaked vegetables generally cause serious digestive disturbances. All vegetables should be thor- oughly cooked, but the cooking should stop while the vegetable is yet firm. As long as the vegetable is kept at a temperature above 125 degrees F. changes con- tinue to go on in the vegetable substance. The most marked of these are in the starch, and in the odor, color, and flavor of the vegetable. Overcooking changes and toughens the texture of vegetable foods, destroys the coloring matters, and volatilizes or other- wise injures the substances which contribute to its flavor. Cooking of Breads and Pastries. — In breads, cakes, pastries and other foods prepared from flour, the aim is to make a palatable and higher porous substance that can be more easily digested than the raw ma- terials could be. Sometimes this is accomplished sim- ply by means of water and heat. The heat changes part of the water content into steam, which, in try- ing to escape, forces the particles of dough apart. The protein (gluten) of the flour stiffens about the tiny bubbles thus formed and the mass remains porous even after the steam has escaped. More often, however, other ingredients, such as yeast and baking powder. ELECTRIC COOKING 41 are used to "raise" the dough. The baking powder gives off carbon dioxide gas, and the yeast causes fer- mentation in the dough and produces carbon dioxide. This gas acts the same as steam, only much more powerfully. Baking of Bread. — Bread is placed in the oven as a heavy uniform mass, and comes out a light body of increased volume with a crisp, dark exterior — the crust • — and a firm, spongy interior — the crumb. The crumb naturally heats more slowly than the crust. The moist- ure which it contains prevents its temperature from rising much above the boiling point of water (212 degrees F.) When first put into the oven the yeast begins to work but a temperature of 158 degrees F. kills it. The gas in the dough, how^ever, continues to expand, and forcing its way outward, enlarges the loaf and gives it a spongy appearance. Meanwhile the crust becomes hard and dark and the heat changes its starch into stiff gum and sugar and dries out the moisture. The brown color is due to chemical changes known as ''caramelization." Baking Temperatures. — The heat in the oven should not be too great, or the outside of the bread will harden too quickly, and the crust will be thick and hard before the interior is done. Furthermore, the gas expanding in the crumb will be unable to escape through the crust and will lift up the latter, leaving great holes beneath it. The temperature of an oven and the time required for baking depends upon the size of the loaves and the character of the dough. Small biscuits or rolls can stand a much hotter oven, and quicker baking, than large bread loaves. For ordinary purposes, a temper- ature of from 400 degrees to 500 degrees F. is satis- factory for a pound loaf of bread. An experienced cook can tell when an oven has reached the proper heat by inserting his hand, but a pyrometer, (as a thermometer for measuring high temperature is called) makes a much better guide for the ordinary operator. CHAPTER V THE ELECTRIC RANGE. Demand for Domestic Ranges. — Interest shown in the domestic range is increasing more rapidly than in any other single heating appliance. In line with the attention now being given to this type of apparatus, and the rapidly growing market for it, the manufac- turers of heating apparatus are making many improve- ments in both their original designs, and character of product. A number of concerns which have heretofore confined their activity solely to the production of fuel stoves, have taken up the manufacture of electric ranges. The result of these developments has been a 50 per cent reduction in range prices during the past five years, greater reliability in the heating units, a larger diversity of designs from which choice of equip- ment can be made, and simpler and more desirable standards of construction. Essential Qualifications of the Electric Range. — The features of the domestic range which make its use desirable to the customer, the central station, and to those having the marketing of the product in hand, are generally agreed upon by all who have given the sub- ject their serious consideration. The range, first of all, must be of substantial and durable construction, and of pleasing appearance. The designs must be stand- ardized as rapidly as possible with the economic object in view of lower costs and increasing production. Sim- plicity of operation and ease of handling and clean- ing are also essential. The heating elements must be rugged, reliable and efficient. Furthermore, they should be so designed as to be easily, quickly, and cheaply renewed whenever troubles develop. The ovens must be well insulated with heat resisting ma- terial, readily accessible, and easily cleaned. Some provision for broiling, either in the oven or on the cooking surface, is generally considered necessary. THE ELECTRIC RANGE 43 It is of interest to note that the early types of ranii^es were so designed as to keep down the connected load and the central station demand as much as pos- sible, whereas the present tendency is to neglect this phase of the design in favor of larger capacity units capable of doing quicker work. This is a step in the right direction. The natural diversity of the range load, and the short period demands which it creates are of little moment in comparison with the necessity for greater speed of operation. Furthermore, there is no reason for believing that a range of high rated capacity will consume any more energy in performing its work than one of lower capacity. The efficiency may be approximately the same with either design. Types of Heating Units. — Heat is usually gener- ated in electric range units by the passage of current through high resistance wires or strips of metallic ribbon. Heating elements in common use may be classified into three diflferent types — first, the enclosed type, second, the radiant type, and third, the reflector type. Enclosed Type Elements. — These usually consist of a resistance wire or ribbon, enclosed between mica or asbestos strips, or surronded with an enamel or other electric insulating material of high thermal conduc- tivity. The element is usually enclosed within, bound upon, or otherwise imposed against, a metal disc or grid which takes up the heat, and in turn dissipates it. The heat generated in such a unit is transmitted from the metal surface to the cooking utensil and thence to the food by conduction. When this type of unit is used in an oven, however, the heat is trans- mitted to the food through the air by convection. It is obvious that this type of element takes a little longer to start heating than do open elements, because the mass of material of which it is composed has to first absorb a certain quantity of heat before it can begin throwing it oflf. It is claimed, however, that this type of element will lose less of the heat generated during a longer period of operation than the open coil element. There are certain apparent advan- 44 ELECTRIC HEATING tages in having the hot wires hermetically sealed, such as the prevention of oxidation and mechanical injury, but unless the insulating materials are able to withstand extreme temperatures they are liable to serious dam- age, if the voltage is higher than normal, or if the ele- ment is connected for a long period without some means of carrying away the excess heat that is gener- ated. Most enamels melt before they reach a tem- perature of 1650 degrees F. (Cherry red). SCCTION fl-A CNLARCLD SECTION B-B Process of Manufacture of General Electric Sheath Wire Heat- ing Elements. Radiant Type Units. — These are usually coils of high resistance wire laid in grooves, or supported on the surface of insulating material. Current passing through this wire brings it to a high temperature, and the heat is transmitted for the most part as radiant heat direct to the utensil or the food to be cooked. Some of the heat, however, is absorbed by the insulating support and some is given off as convected heat both from the support and from the wire itself, the percentage varying with the design of the unit and its composition. In a well designed unit much of this convected heat is finally taken up by the food. Radiant type units begin to throw off a large amount of heat almost as soon as the current is turned on. The heat in the coils, is visible on account of the high temperature. The nature of the radiant heat THE ELECTRIC RANGE 45 given off makes it possible to use the ordinary kitchen utensils to better advantage on the open than on the enclosed type elements. The coils being exposed, however, and the supports, as now manufactured, being somewhat brittle, this type of unit is to some extent liable to mechanical injury, short circuits, and grounds. It is also harder to keep clean than the enclosed type element. Hug-hes Open-Type Element. Reflector Type Element. — Use is here made of the heat reflection principle. It usually consists of exposed coils of wire surrounded by air and supported adjacent to a bright metallic reflector. Part of the heat generated in the coils passes directly to the cooking utensil or to the food in the same manner as from the ordinary radiant type element. Another portion of the heat travels in the opposite direction until it reaches the polished surface, where it is reflected back on its course to the cooking utensil. A small percentage of the en- ergy is, of course, given oflf as convected heat and some passes away through the reflector. This type of element heats quickly, makes possi- ble the use of most ordinary kitchen utensils, and pro- 46 ELECTRIC HEATING duces a visible heat in the coils. It is, however, more subject to mechanical injury than the enclosed type element. The reflectors, although they can be easily and cheaply replaced, are also likely to become discol- ored and become inefficient on account of the intense heat. The future development of a cool reflector, how- ever, may do away with the latter objection. Types of Electric Ranges. A large variety of electric ranges are manufac- tured in this country. They are available in many styles and capacities, and at various prices. Each of them has been developed with certain individual characteristics in design or operating features, having some advantages over those of other makes, but all of which could not possibly be incorporated in any single design. This chapter is therefore devoted to descriptions of the most prominent makes of electric ranges in order to convey a general understanding of the design, construction and individual characteristics of the types now available. Hughes Ranges. — This make of electric range has been on the market for a number of years. It is made in a large variety of shapes and sizes, in either the high oven, low oven, or cabinet types, and in capacities ranging from 4140 to 10,340 watts. The frame is con- structed of black heavy gauge sheet metal supported on cast iron legs. The legs, top, and fittings are nickel finished in most of the designs. The general con- struction is rugged and of handsome appearance. The heating elements are of the open or radiant type and consist of coils of resistance wire held in place below the cooking surface by means of a grooved composition block. This block is in turn, surrounded by another block of asbestos compound having high thermal resistance. The units may be easily removed with a screw driver and pliers. The oven is thoroughly insulated with mineral wool. The interior of the oven is finished in black enamel. The doors are of the drop shelf type and are usually trimmed in nickel and white porcelain enamel THE ELECTRIC RANGE 47 Thermometers are fitted in these doors. There are two heating elements in the oven — one in the top, and the other in the bottom. Each of these units is regu- lated by a three heat switch. The top unit is used for broiling. An enameled tray and rack for this pur- pose are provided with each range. Some of the higher priced ranges are supplied with white porce- lain enamel splashers around the cooking surfaces, which add materially to the appearance of the equip- ments. Type. No. Style. C-2 C-3 C-4 Cabinet Cabinet Cabinet Wattage. 2-880 HUGHES RANGES. Cook Oven No. Dimensions. Elemen 18x12x12 2-880 18x12x12 2-1100 18x18x12 C-18 Low oven No. 27 Low oven No. 30 Low oven 2-880 2-880 2-880 18x12x12 18x12x12 18x12x12 No. 33 High oven 2-880 18x12x12 No. 37 Low oven 2-1100 18x18x12 No. 40 Low oven 2-1100 18x18x12 No. 44 High oven 2-1100 18x18x12 No. 47 Cabinet 2-1100 18x18x12 W^armer- 21i4x20x9 No. 48 Low oven 2-1100 18x18x12 No. 50 Cabinet 2-1100 18x18x12 W^armer- 211^x20x9 No. 56 Cabinet No. 60 Cabinet 1-1800 18x18x8 2-1100 18x18x12 Warmer- 21^/4x20x9 1-1800 18x18x8 2-1100 18x18x12 Warmer- 21^/4x20x9 ng Surface. Total Wattage Wattage s. (of Each) of Range. 1500 880 1500 1100 880 1500 1100 880 1500 880 1500 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 1500 1100 880 4140 5240 5680 4140 4140 5240 5240 5680 6560 6560 5680 8540 6560 8360 10340 48 ELECTRIC HEATING Hughes No. 50 Cabinet Range. Simplex Ranges. — These ranges were first put on the market about nineteen years ago. The modern domestic types usually consist of an oven, a broiler, and several disc heaters. They are made up in either the low oven, or cabinet type, and in capacities rang- ing from 3100 to 8200 watts. They are finished in black japan. The general construction is rugged and compact. The heating units are of the enclosed type, the resistance wires being embedded in enamel, and fused to the under side of the cast iron discs. The discs protrude slightly above the top of the range, and are provided with a simple locking device by which the utensils are clamped fast to the heating surface to insure good contact. The units are fastened to the frame with thumb screws. The utensils included THE ELECTRIC RANGE 49 with each range are made of heavy copper, nickeled outside and tinned inside. The broiler is mounted on the cooking surface. It consists of a corrugated heating plate slightly inclined toward the front, from which an outlet carries off the juices for serving with the meat. A separate smooth top fits on the broiler for making griddle cakes, etc. The oven is made of Russia iron with japan finished iron frame and nickel plated trimmings. The walls are heavily insulated with corrugated asbestos and provided with a vent. The heating elements in both SIMPIiEX RANGES. Cooking Surface. Total Type. No. Style. Wattage. —Oven No. of Dimensions. Elements. Wattase (of Each) Wattage of Range, 4K Low oven 1300 15x12x111/2 1 2 440 735 3210 5K Low oven 1300 1300 15x12x111/2 9x12 broiler 1 1 440 735 3775 6K Low oven 1600 1300 15x18x111/2 9x12 broiler 2 J. 440 735 4515 7K Low oven 1600 1300 15x18x111^ 9x12 broiler 1 2 440 730 4810 8K Low oven 1600 1300 15x18x111/2 9x12 broiler 2 2 440 735 5250 9K Low oven 1600 1300 15x18x111/2 9x12 broiler 1 2 i 440 735 1100 5910 14K Low oven 2400 2200 211/2x19x13 12x18 broiler 1 1 1 1 440 735 1100 1300 8175 21K Cabinet 1600 1300 200 15x18x111/2 2 9x12 broiler 1 15x15x7 warmer 440 735 4715 22K Cabinet 1600 1300 200 15x18x111/2 9x12 broiler 15x15x7 warmei 1 2 440 735 5010 23K Cabinet 1600 1300 200 15x18x111/2 2 9x12 broiler 2 15x15x7 warmer 440 735 5450 24K Cabinpt 1600 1300 200 15x18x111/2 9x12 broiler 15x15x7 warmer 1 2 1 440 735 1100 6110 31K Cabinet 1600 1300 15x18x111/2 9x12 broiler 2 1 440 735 4515 32K Cabinet 1600 1300 15x18x111/^ 9x12 broiler 1 2 440 735 4810 33K Cabinet 1600 1300 15xl8xllV2 9x12 broiler 2 2 440 735 5250 34K Cabinet 1600 1300 15x18x111^ 9x12 broiler 1 2 1 440 735 1100 5910 50 ELECTRIC HEATING Simplex No. 7-K Range. top and bottom are of the enclosed grid type, and are controlled by a single three-heat switch. The oven door is of the drop shelf type, fitted with an indicating thermometer. General Electric Ranges. — Ranges of this make have been on the market for a considerable time and the makers may be credited with having done a great deal of development work. These ranges are now manufactured in two standard types — the "R" type and the "S" type, either of which are available in either the high oven, low oven, or cabinet styles. The **R" type was first developed. It is of heavier and better construction, provided with special "Calorox" oven insulation, and is likewise more ex- pensive. The ''S" type is a later development. The frame of the range is made by a fuel stove manufacturing concern. The heating units and other electrical fea- tures are provided by the General Electric Company. THE ELECTRIC RANGE 51 General Electric No. R-2 Range The ovens are equipped with separate top and bottom heating elements and provision made for broiling inside. The standard oven dimensions on each range is 18 in. by 18 in. by 12 in. It is of interest to note that all the heating ele- ments used on ranges made by this company have been of the enclosed type. The ''D" type unit which has been discarded for some time, consisted of a ribbon wire resistance clamped between mica strips and fas- tened to the bottom of the element. The units used on the "R" and "S" type units are made up by pour- ing molten iron around sheathed wire. This so called "sheated wire" consists of a small hollow wire enclos- ing a fine resistance wire, the space between being filled with an insulating material of high thermal con- 52 ELECTRIC HEATING GENERAL ELECTRIC RANGES. Type. Style. ( 3ven Dimensions. Cooking No. of Elements. Surface. Wattage (of Each) Total Wattage of Range. No. Wattage. R-1 Low oven 2-1000 18x18x12 2 3 1000 200* 4600 R-2 High oven 2-1000 18x18x12 2 3 1000 200* 4600 R-3 R-4 Cabinet oven Cabinet oven 2-1000 18x18x12 1-300 warmer 2-1000 18x18x12 2 3 2 3 1000 200* 1000 200* 4900 4600 S-1 Low oven 1-1000 1-1500 18x18x12 3 1000 5500 S-2 High oven 1-1000 1-1500 18x18x12 3 1000 5500 S'-3 Cabinet oven (♦cookers) 1-1000 1-1500 18x18x12 3 1 1000 200* 5700 due tivity (presi amably aluminum or other metallic oxide). Vegetable cookers may be substituted for any one or all of the top heating units if desired. These cook- ers are heavily insulated and consume little current. They are especially useful for preparing stews, vege- tables, cereals, etc. All the elements on the stove have plug connec- tions and may be changed by anyone without the use of any tools. Westinghouse Ranges (Copeman Patents). — These ranges are at present manufactured in two standard styles — the low oven type known as the 2-19, and the cabinet type known as the 3-19. Either of these ranges may be obtained in either plain or nickel finish, and may or may not be provided with the special automatic feature. The cabinet type is always equipped with white porcelain enamel splashers around the cooking surface. The construction of both ranges is substantial. The legs and frame are of cast iron, and other parts of sheet steel. Open or radiant type elements consisting of coils of resistance wire, held in place in spiral grooved com- position blocks are used. The cooking surface on each of these ranges consists of two 8 in. 1000 watt units, and one 10 in. 2000 watt unit. The latter is so connected that the low heat utilizes the inner third THE ELECTRIC RANGE 53 » I I Westinghouse 3-19 Automatic Range. of the surface, medium the inner two-thirds of the surface, and high the entire 10 in. surface. The ovens are thoroughly insulated with mineral wool. The oven doors open to the side. The interior dimensions of the oven are 18>^ by 13^ by 16 in. The cabinet type range is provided with a small boiling oven (10^ in. by ISjA in. by 11>^ in.) in addition to the large oven. Provision is made also for broiling in the large oven. Either type range may be equipped with a relay, whereby the current will be automatically turned off 54 ELECTRIC HEATING WESTIXGHOUSE RAIVGKS. Cooking Surface. Total Type. 0\en -\o. of Wattage. Wattage No. Style. Wattage. Dimensions. Elements. (of Each) of Range. No. 3-19 Cabinet 2-1000 181/2x131/2x16 1 2000 1-850 10 %xl3 1/2x11 1/2 2 1000 6850 No. 2-19 Low oven 2-1000 18 1/2x13 1/2 xl 6 1 2000 2 loOO 6000 No. 406 Low oven 1-1000 16x12x111/2 2 1000 1-660 3660 when the ovens reach a certain desired temperature. The cabinet type range, furthermore, may be equipped with a clock device, whereby the current may be auto- matically turned on in the oven at any desired time. The number 406 range is smaller than the two standard styles and of less expensive construction. Olston Ranges. — These ranges have been on the market for several years and are made in one-oven, two-oven, and three-oven types and in capacities vary- ing from 1980 watts to 4620 watts. They are con- structed of sheet iron, enameled in gray, and trimmed in nickel. The ovens are mounted on sheet metal legs, and are easily accessible without stooping. No heating elements are furnished for top cook- ing, but flush receptacles for attaching disc stoves and other heating devices, are provided. The oven ele- ments are of the open type. OLSTEN RANGES. Total Type. Oven \\attage No. Style. Wattage. Diniens ons of Range. 1 Low 1980 111/2x111^x18 1980 2 Low 2970 (111^x111^x18 (iiy2Xllv2Xl8 2970 3 Low 4620 (lli/2xliy2Xl8 X i i > X 4 Wall type. Same as No. 1. 5 Wall type. Same as No. 2. (13 %xl2 1/2x21) 4620 The ovens are heavily insulated with mineral wool and are provided with drain cups to collect the excess moisture caused by condensation. The doors open to the side. The ovens are controlled by flush snap switches and the temperatures are regulated by ther- mostatic devices, which automatically maintain any desired temperatures for which they are set. When THE ELECTRIC RANGE 55 the required heat is generated, the current switches off, and v/hen the oven cools a few degrees, the cur- rent is switched on, thus maintaining a constant tem- perature. Pilot lamps, mounted over the temperature control dials, indicate at all times whether or not current is being consumed. No. C Good H( ■keeping Cooker, Good Housekeeping Cocker. — This device, which has been on the market for several years, has been known as the automatic steam cooker, or the Berkeley cooker. Although the principle of operation has not been changed, its mechanical construction has been greatly improved. The cylindrical outside shell is 14 inches in diam- eter and made of polished sheet steel. The cast iron base and top are trimmed in nickel. Two 8 inch enclosed type disc elements of 1000 watts capacity each, may or may not be -mounted on the cooker surface. The top of the cooker is 31^^ in. from the floor. A 56 ELECTRIC HEATING GOOD HOUSBKGKPING COOKER. Cooking Surface. Total Type. Cooker Pot No. of Wattage Wattage No. Style. Wattage. Dimensions. Elements, (of Each) of Range. A Cooker 550 14 gallons None 550 C Cooker 550 14 gallons 2 1000 2550 small ovenette, for use over one of the discs, may be obtained with the cooker. The space provided in the cooker is approximately 13 inches deep and has a capacity of about 14 gallons. The walls and cover are heavily insulated with mineral wool and granulated roasted cork. The cooking compartments consist of two cylin- drical copper jackets welded one within the other with a slight space between, from which the air is exhausted, and a small quantity of water and ether introduced. An enclosed type heating element of 550 watts capacity is fastened to the bottom of the outer jacket. A dia- phragm, the buckling of which, actuates a contact lever controlling the flow of current in the heating element, is made a part of the outer compartment jacket. At a temperature of 250° F., a steam pressure of 15 pounds is produced causing the diaphragm to buckle, thereby actuating the lever, and cutting off the current to the heating element. At 220° F. the pressure is reduced with the result that the element is again connected. This action is continued as long as the cooker is in service. An automatic clock device, for turning the current on in the cooker at a prede- termined time, is also provided with each equipment. Globe Ranges. — The Globe Stove and Range Com- pany which has confined its efforts to the production of wood, coal and gas stoves, for many years has re- cently taken up the manufacture of electric ranges. Those w^hich have thus far been placed on the market possess several novel and attractive features. The desire of the average women for bright enamel and nickel trimmings has been catered to in the finish of the ranges. The sheet metal parts are made of twenty gauge Armco iron with white enamel on one side, and ground coat on the other. The ovens are insulated with three inches of "Sil-o-cel" and lined with sixteen gauge Armco iron. THE ELECTRIC RANGE 57 One-quarter inch steam packing gaskets insulate the oven from the front frame of the stove, and also sep- arate the inner and outer casings of the door. Heavy- latches used on the oven doors make them practicall}' air tight. Globe No. B-5 Range. The heating elements used in the oven are of the enclosed type in the bottom, and of the open coil radiant type in the top, for broiling operations. The top surface elements are unique in that they combine, in a measure, the features of both the open and en- 58 ELECTRIC HEATING closed types. Resistance wires, wound in flat helical coils, are fastened in grooved porcelain plates, and protected with thin cast iron plates ^' ' ' are grooved to correspond These plates with the position of the globe: ranges. Tjpe. Style. c Oven N 'ooking 0. of ments. Surface. Wattacre (of Each) Total Wattaf?e of Range. No. Wattage. Dimensions. Ele A2 Dow oven 1-1500) 1-2000) 191^x19^x13 2 1500 Low oven 1-1500) 1-1000) liy2Xl9%xl3 2 800 10.600 A3 Cabinet 1-1500 1-1000 Iiy2xl9%xl3 9 2 1500 800 7.100 A4 Low oven 1-1500 1-1000 Il%xl9%xl3 2 2 1500 800 7,100 Bl Low oven 1-1500 1-1000 13^4x1314x1914 2 2 1 1500 800 330 7.430 B2 Cabinet 1-1500 1-1000 13%xl3i4xl9i4 2 2 1 1500 800 330 7.430 B3 Low oven Special 1-1500 1-1000 13 1/4x19 1/4 X131A 2 1 1500 800 6,300 B3 Low oven 1-1500 1-1000 I3V4XI914XI31/4 2 1 1500 330 5,830 B4 Cabinet Special 1-1500 1-1000 131/4x191/4x131/4 2 1 1500 800 6,300 B4 Cabinet 1-1500 1-1000 1314x1914x13^ 2 1 1500 330 5,830 B5 High oven 1-1500 1-1000 131/2x191/2x131/2 2 1 2 1500 330 800 7,430 wires. It is therefore apparent that a utensil placed over one of the heatins: elements is heated by both radiant and conducted heat. Estate Ranges. — The Estate Stove Company is re- cently bringing to bear its many years of experience in the construction of fuel stoves and ranges, in the manufacture of electric ranges. Three standard tyr>^'^ have thus far been placed on the market. The ranges are of substantial construction, resembling the stand- ard gas ranges in appearance. The cast iron parts are treated with a coat of ebonite, and the sheet metal parts are made of rust resisting steel. The oven doors and broiler pans are of white enamel, as are the splasher backs in the cabinet type ranges. The cooking surface elements are of the enclosed type, consisting of nichrome wire, wound around mica THE ELECTRIC RANGE 59 discs, and clamped between iron plates. These plates are connected by means of plugs which fit into re- ceptacles and may he removed or connected as easily as any ordinary socket plug. The heating elements in the ovens are also of the iron clad type with the No. S4 Estate Range (with Cookers Attached). exception of the broiling elements, which are of the radiant type. The ovens are of ample capacity for ordinary baking and roasting, and are heavily insulated. The doors, which open to the side, are strongly latched and fitted with thermometers. Broiling operations are performed in the ovens, except in the No. 84 cabinet range, which is provided with a separate broiling com- partment mounted below the oven. The cylindrical fireless cookers, which may be hinged to the legs of the cabinet type ranges and swung out of the way when not in use, are a special feature. These cookers are heavily insulated, have interior dimensions of 8 inches depth by 10 inches diameter, and consume 500 watts each. . 60 ELECTRIC HEATING ESTATE RANGES. Tvi-f. Style Wattage. Cooking No. of Elements. Surface. Total Wattage W.ittage (of Each) of Range. No. Dimensions. 83 Low oven 1030) 1370) 18x12x12 2-61/2 in. 1-8 in. 650 1200 4900 84 Cabinet 1500) 2000) 1500 18x18x12 Broiler 3 -6 1/2 in. 1-8 in. 650 1200 8150 88 Cabinet 1500) 2000) 18x18x12 3-6 1/2 in. 1-8 in. 650 1200 6650 Rutenber Ranges. — After several years experience in the manufacture of electric ranges the Rutenber Electric Company has adopted three standard low oven types which are made up in either plain or nickel finish. No. 115 Rutenber Range. The frames of the ranges are made of cast iron and the sheet metal parts of blue polished steel. The heating elements are of the radiant type, con- sisting of coils of wire laid in grooves of a special THE ELECTRIC RANGE 61 moulded clay compound. Each range is provided with two such elements. The ovens are heavily insulated with rock wool and the interior walls are made of a special alloy. RUTENBER RANGES. lype. style. Cooking No. of Elements. Surface. Watta-e. (of Each) Total Wattage of Range. No. Wattage. Dimensions. 105 Low 2-1000 18x18x14 4 1000 6000 110 Low 2-800 18x18x14 3 1000 4600 115 Low 2-800 18x12x14 2 1000 3600 The doors open to the side, are heavily latched to pre- vent the loss of heat, and are fitted with standard oven thermometers. Acorn Ranges. — Rathbone Sard & Company, which has been the maker of the well-known Acorn fuel ranges for many years, has recently taken up the man- ufacture of electric ranges. It now has a line of these new ranges, consisting of two low oven types and five cabinet types. It will be noted that the low oven types are the same except that one has three surface elements, whereas the other has four. The cabinet type ranges have the same number of surface elements, 62 ELECTRIC HEATING ACORN RANGES. 1 Xo. El ■yi>o. St.vle. Low Oven Cooking Surface. Wattage (of Eacli) 1000 Total Wattage of Range. 5500 Wattage. 1-1500 1-1000 Dimensions. Elements. 18x14x18 3-101/^ in. E5 Low 1-1500 1-1000 18x14x18 4-101/2 in. 1000 6500 ElO Cabinet 1-1500 1-1000 18x14x18 4-101/2 in. 1000 Plate warmer 18x10x18 6500 E20 Cabinet 1-1500 1-1000 1-1500 18x14x18 18x10x18 4-101/2 in. 1000 8000 E30 Cabinet 1-1500 1-1000 1-1500 18x14x18 18x10x18 4-101/2 in. 1000 Plate warmer 18x10x18 8000 E40 Cabinet 1-1500 1-1000 18x14x18 Plate warmer 18x10x18 4-101/^ in. 1000 6500 EoO Cabinet 1-1500 1-1000 Warmer 18x14x18 18x10x18 ■i-lOMi in. 1000 Plate shelf 18x10x18 6500 the same dimension and capacity baking and warming ovens, and occupy the same floor areas. The frames are made of cast iron and the sheet metal parts of heavy gauge iron. They are finished plain or equipped with white enameled splashers and nickel trimmings. The ovens are lined with a special heat insulating material known as "duro-therm." They are provided with white enameled doors and broiler pans. The doors are also equipped with thermometers and posi- tive tight closing latches. The heating elements of the cooking surfaces are the standard General Electric sheathed wire enclosed types, whereas the oven units are the sheathed wire radiant types. Two hundred watt vegetable cookers may be substituted for any one of the surface cooking elements. Standard Ranges. — The Standard Electric Stove Company, successors to the Detroit Fireless Stove Company, has developed a line of electric ranges which is different from other makes in several particulars. The ranges are made of Armco iron, finished in blue enamel, and nickel trimmed. The ovens and cooker pots are thoroughly insulated with rock wool, and lined with aluminum. THE ELECTRIC RANGE 63 The compartments are mounted with the covers even with the cooking surface. These covers are hinged at the back and provided with locking devices. The compartments and surface heating elements are ^^j|^^^H standard No. 500 Range. mounted side by side in a line parallel with the front of the stove. The ovens are mounted above the cook- ing surface and fitted with plate glass doors. The oven elements are of the radiant type. The compartment and surface heating elements are of the STANDARD RANGES. No, Type Style. Cooking No. of Elements. Surface. Wattage (of Each) Total Wattage of Range. Wattage. Dimensions. 300 Low cooker 1-660 cooker 2 1000 2660 400 Low cooker 2-660 cooker 2 1000 3320 500 Hig-h oven Low cooker 2-800 1-660 11x12x161/2 cooker 2 1000 4260 501 High oven Low cooker 2-1000 1-660 11x12x19 cooker 2 1000 4660 600 High oven Low cookers 2-800 2-660 11x12x161/2 cookers 2 1000 4920 601 High oven Low cookers 2-1000 2-660 11x12x19 cookers 2 1000 5320 64 ELECTRIC HEATING enclosed type, consisting of resistance wires, baked in a special cement composition which is backed up with an iron shell. The high oven types are provided with an auto- matic device which may be set to turn the current off after the food has cooked a certain length of time. Control switches and pilot lamps, mounted on the frame of the ranges, are also desirable features. Garland No. 26 Range. Garland Ranges.- — The Michigan Stove Company, one of the larger manufacturers of fuel stoves has re- cently placed a new line of electric ranges on the mar- ket which are somewhat different from other makes of electric stoves. They are made up by various com- binations of interchangeable parts in much the same way as sectional book cases. The cast iron frame and sheet steel parts are coated with black enamel, and the bright parts are nickeled. Doors, broiler pans, and splashers are also white enameled. The heating elements consist of resistance ribbons, wound on mica cores, and incased in sheet steel covers, forming flat strips or bars % in. in width. Six of these strips, each of 200 watts capacity, are mounted THE ELECTRIC RANGE 65 side by side to form a heating unit. These units or grids are separately fused and located on top of hinged plates. The cooking tops are built with either two or three grids. The special indicator switches which are mounted on the grids are very desirable as their positions may be determined at a glance. The oven is of a single standard size and may be used alone, or made a part of several combinations with the grid tops. The aluminized steel inner wall is surrounded with an inch air space, which is in turn insulated with an inch of special material. The dou- GARI^AND RANGES. Type. Style. Cooking No. of Elements. Surface. Wattage (of Each) TotPl Wattage of Pange. No. Wattage. Dimensions. 21 Low 2-1200 18x12x12 2 1200 4800 23 Low 2-1200 18x12x12 4 1200 7200 25 2-Low 4-1200 18x12x12 6 1200 12000 26 Cabinet 2-1200 18x12x12 2 1200 4800 27 High 2-1200 18x12x12 2 1200 4800 28 Low 2-1200 18x12x12 4 1200 7200 31 Low 2-1200 18x12x12 3 1200 6000 33 Low 2-1200 18x12x12 6 1200 9600 36 Cabinet 2-1200 18x12x12 3 1200 6000 ble door is made up in much the same way as the oven walls and is provided with a tight latch. Broiling is performed in the oven by placing the meat on adjust- able pans, which press it against wire bars below the grids. Hotpoint Ranges. — After many years successful experience in the production and marketing of lamp socket heating devices the Hotpoint Electric Heating Company has extended its efforts to the construction of electric ranges. The five types of ranges now man- ufactured are made of cast iron and sheet steel. They are attractively designed and trimmed in nickel and white enamel. The ovens are heavily insulated with mineral wool. The doors latch tightly and may be fitted with glass if desired. The lining of the ovens is made of alum- inized steel. The cooking surfaces are hinged at the back, thus permitting easy access for inspection or repairs. The 66 ELECTRIC HEATING heating elements are of the open coil radiant type, mounted above polished concave reflectors which col- lect the heat rays passing downward and direct them backward against the utensils. The reflectors are mounted on the crumb trays below the cooking sur- faces, and may be easily removed for cleaning. HOTPOINT RANGES. No. Type. Style. Waflage. Cooking —Oven No. of Dimensions. Elements. Surface. Wattage (of Each) Total Wattase of Range. D Cabinet 2-1200 181/2x181/2x12 1 *18i^xl8xl0 1 1500 1200 800 6,700 E Cabinet 2-1000 16 1/2x1 6 1/2x1 11/2 1 *12i/2Xl2i/^xlOi/2 1 1500 1200 800 5,500 F High oven 2-1000 181^x161/2X111/2 1 1500 1200 800 5,500 G Low oven 2-1000 181^x16x11% 1 1500 1200 800 5,500 H Low oven ♦Warming 2-1000 closets. 16x14x12 1 1500 800 4,300 Hot Point Range. Other Types of Ranges. — The recent rapid devel- opment of the electric range market has served to arouse latent interest in their production. A number of manufacturers of electric heating devices and fuel THE ELECTRIC RANGE 67 I ranges have signified their intention of designing and marketing electric ranges in the near future. The effort that is being put forth by the central stations and manufacturers to popularize and create a market for electric ranges must result in improved apparatus, standardization of design and eventual lowering of production costs. CHAPTER VI COMMERCIAL COOKING. Opportunities in Hotels and Restaurants. — The substitution of electric for fuel heating apparatus in hotels, restaurants and institutions presents enor- mous commercial possibilities. Consideration of the opportunities afforded the central station companies, and the manufacturers of heating devices, however, have only recently been given favorable attention. The savings and other advantages accruing to the cus- tomer, the tremendous possibilities for building up attractive central station loads, and the ever widening market for the various kinds of electric heating de- vices in the modern hotels and restaurants, make the subject one of mutual interest worthy of serious con- sideration. Advantages of Electric Cooking. — Most of the ad- vantages already cited in favor of electric ranges in the home, apply to the use of electric cooking equip- ment in commercial enterprises to an even greater ex- tent. The absence of dirt, smoke, excessive heat, and poisonous fumes, the advertising value of the clean sanitary kitchen, the improvement of food, and the saving in floor space, fuel storage capacity, and meat shrinkage, are all points of superiority that create keen interest. Careful Planning Essential. — In spite of the ad- vantages of electric cooking service in the modern hotel and restaurant kitchen, many failures have occurred. These have frequently been due to unwise selection of apparatus, lack of appreciation of the users' requirements, or the adverse attitude of a cook or chef. A careful preliminary study of each individual condition is of extreme importance if success is to be achieved. COMMERCIAL COOKING 69 It is first necessary to know the approximate max- imum amount and kinds of food that will be served, how long a period will be allowed in which to serve them, how long they must be kept warm, etc. It is always necessary to consider maximum conditions. Unlike fuel apparatus electric equipment cannot be forced under conditions of stress. The attitude, intelligence, and often the nation- ality of the cooks who actually operate the apparatus is worthy of serious consideration. The care and skill with which electric devices are manipulated, have General Electric Ranges and Broilers in Bethlehem (Pa.) Steel Company's Kitchen. much to do with their successful operation. Many cooks trained by long experience in the actual prepa- ration of food, dislike to take up new methods. Others are intellectually unfitted or flatly refuse to learn. Choice of Apparatus. — In laying out an installation it must be remembered that the equipment will be subjected to extremely rough usage. Only the best and most substantial apparatus available should be in- stalled. It should be designed for easy control. The cooking surface of the range should be of adequate capacity because much top cooking is done in the 70 ELECTRIC HEATING average hotel or restaurant. A few extra capacity units for rapid work are usually required. Prelimi- nary advice, as to the kind of utensils that will give the quickest and most efficient results, will also be helpful to the user. Shrinkage in Meats. — The tendency to minimize the importance of meat shrinkage by the management of hotels and restaurants is very general, but never- theless such losses are worthy of serious considera- tion. The enormous v^aste resulting from the ordinary fuel methods of preparing meats, coupled with its high Special Hughes Cooking Surface and Standard Meat Roasting Oven in Cafeteria, Sacramento, Cal. cost and serving value, make the savings effected by the application of electrical methods of real importance, especially where large quantities of meat are cooked daily. To those who have actually observed meats pre- pared by both fuel and electric means the saving is obvious. A great many actual tests have been made, and universally the results have shown a marked sav- ing in favor of electricity. The following table is a I COMMERCIAL COOKING 71 compilation of experiments made by Mr. K. B. Mat- thews of England in the preparation of beef and mut- ton with coal, gas, and electricity: Weight Weight before after Type Loss of Loss cooking. cooking. of weight. per lb. oz. lb. oz. Oven lb. oz. cent. Ribs of beef 5 7 3 12 Coal 1 11 31.0 Leg of mutton 8 8 5 13 Coal 2 11 31.7 Shoulder of mutton. . . 6 13 5 1 Coal 1 12 25.7 Leg of mutton 8 4 6 Gas 2 4 28.1 Leg of mutton 9 7 12 Elec. 1 4 13.1 Shoulder of mutton. . . 4 12 4 2 Elec. 10 13.1 Ribs of beef 9 17 6 Elec. 1 11 18.6 Leg of mutton 9 1 7 10 Elec. 1 7 15.8 Shoulder of mutton. . . 5 10 5 Elec. 10 11.1 General Electric Ranges in Galley of U. S. S. Texas. Apparatus Available. — Only a few manufacturers of electric heating devices in this country have under- taken the extensive production of commercial cooking apparatus. There are several reasons for this condi- tion. Development work is expensive and the market for the equipment has, until recently been limited. Only such apparatus as will "stand up" under the severest kind of operating conditions ever proves sat- isfactory. The rather sad experience, which some con- cerns have had in attempting to utilize the less rugged 72 ELECTRIC HEATING types of domestic cooking devices for hotel and res- taurant service, has exerted a somewhat discouraging efifect on further development. There is no doubt, however, but that the experi- ence gained thus far, has been valuable. The types of apparatus that have stood the test have been ex- tremely satisfactory to the users, and now that so many improvements have been made in the design of heating apparatus, there is no question but the market will develop rapidly and result in quantity pro- duction and further price reduction. General Electric Type D-54 Range in Dietary Kitchen in Penn- sylvania State Hospital, Philadelphia, Pa. As quite a few types of apparatus designed ex- clusively for commercial cooking service are now avail- able, some of the features of those best known will be described. Hotel Ranges. — No other piece of kitchen equip- ment is subject to such severe treatment as the hotel or restaurant range, especially the top cooking sur- face. Earlier installations were either too frail, too small, or too slow in heating to give satisfaction. The modern types, however, are heavily constructed, COMMERCIAL COOKING 73 available in adequate capacities, and generally pro- vided with sufficient wattage in the heating units to perform work quickly. General Electric Hotel Range. — This type of range is constructed of heavy cast iron, and steel sheet metal. The oven walls are well insulated with navy firefelt. The cooking surfaces are composed of eight oblong 9^ by 12 in. enclosed type cast iron heating units, placed side by side, arranged with four 1600 watt units in front for high temperature cooking, and with four 800 watt units in back for lower temperature work. There are two ovens, each having a capacity of 4800 watts, and inside dimensions of 18 in. width, 28 in. depth and 16 in. height. The doors are heavily constructed and are of the drop type. All the heating units are fused and controlled by knife switches located in a sheet metal compartment above and at the rear of the cooking surface. The overall dimensions of the range are width 44 in., depth 38 in. and height to top of switch box 68 in. The maximum rated capacity is 19.2 kilowatts. An equipment sufficiently large to take care of any requirements can be provided by placing as many of these ranges side by side as are necessary. Simplex Hotel Ranges. — The high duty ranges manufactured for hotel and restaurant service are made of much heavier materials than those designed for domestic use. The parts are constructed of heavy gauge steel and cast iron. The general appearance is much the same as that of the more elaborate hotel fuel ranges. They are ordinarily made up in complete sections consisting of a cooking surface 7 ft. 6 in. long by 2 ft. 9 in. wide, with two ovens mounted beneath. For very large installations, two or more of these sections are placed, end to end, or back to back. The cooking surface is usually made up to suit the customer's requirements. The units may consist of any suitable arrangement of the following heating elements in various capacities : 74 ELECTRIC HEATING Rim or flat griddles, 9 in. by 12 in., 12 in. by 18 in. or 18 in. by 24 In. sizes. Hotel broilers, 9 in. by 12 in., or 12 in. by 18 in. sizes. Disc stoves 4i/^ in. diameters to 20 in. diameters together with special heavy copper kettles and other utensils of similar dimensions. Deep fat frying kettles — 12 in. diameter, 5 in. deep. Hotel toasters — 10 in. by 12 in., or 12 in. by 18 in. sizes. Waffle irons — two or three section (for 4 V^ in. waffles.) Simplex •ovtn Range, ^V'eit■a^e DiUtng Hall, Kdison Electric Illuminating Company, Boston. The ovens are of heavy construction, well insu- lated and provided with massive drop doors. The Foi ■tion Simplex Range, Montana State Hospital, Billings. interior dimensions are 24 in. wide, 27 in. deep, and 16 in. high. The oven heaters are located in both the top and bottom. i COMMERCIAL COOKING 75 Kach range section is supplied with a distributing panel, located between the ovens and accessible from the front. The circuits are separately fused, and each device has its own control switch, and pilot light. Meat Broilers. — Two types of broilers are made — the open type and the enclosed type. It is safe to Hughes Meat Broiler. say that better results can be secured with either of these types than are attainable with any kind of fuel broiler. The Simplex open type apparatus consists of a corrugated cast iron surface slanting slightly towards 76 ELECTRIC HEATING a grooved end. The meat rests on the hot surface and the juices are collected at the mouth of the groove and poured over the meat before serving. The heating is done by means of a sealed-in unit under the corrugated surface. The standard hotel size is 12 in. by 18 in. and has a capacity of 2200 watts. The Hughes Broiler is of the enclosed type and is manufactured in three standard sizes. The smaller size has interior dimensions of 18 in. by 30 in. by 8 in. and has a capacity of 4.5 kilowatts. The medium size is composed of two compartments placed side by side, each having the same dimensions and capacity. The large size is 32 in. by 30 in. by 8 in. and has a capacity of 10 kilowatts. The walls of these broilers are heavily insulated. The units are of the open type and give off radiant heat. The exteriors are finished in black iron, and the bodies are supported on angle iron frames. The General Electric broiler is of the enclosed type and equipped with radiant heating elements. The General Electric Meat Broiler. broiling area is 14 in. by 20 in. The rated capacity is 5 kilowatts, of which 4.5 kilowatts is used during actual operation and 500 watts for maintaining the temperature when the device is not in service. It is COMMERCIAL COOKING 77 made of heavy sheet steel and angle iron construction and the walls are thoroughly insulated. It is mounted on angle iron supports. Hot Closets. — Hot closets are required in almost every hotel and restaurant kitchen for keeping food and dishes warm. They generally consist of double walled or well-insulated ovens with oue or more shelves, doors opening to the side, and equipped with Cutler-Hammer Hot Closet. relatively small heating units mounted in the bottom. They are usually provided with three-heat control switches. The Hughes and Simplex warming ovens are made up in several standard sizes but may be de- signed in any special size or capacity. Steam Tables. — When food must be kept warm for any length of time for serving, a steam table is usually considered a necessity. Either immersion or circulation heaters may be used for this purpose. Immersion heaters may be inserted through the top or in the side of the steam table. They must be 78 ELECTRIC HEATING kept covered with water constantly, or the elements will burn out. Circulation heaters of various types may be util- ized in heating a steam table by connecting them with pipes to the bottom of the tank and placing the heat- ers at an angle of about 10° to 15° with the horizontal. The colder water reaching the lower end of the heater will rise in temperature and gradually pass up through the heater into the tank, thus creating a constant cir- culation and gradual heating of water as long as the current is applied. 'Neuco" steam Table. It is essential that steam tables be well insulated against heat losses. If the circulation method of heat- ing is employed, the pipes leading to and away from the heater should be well lagged. In making calculations of the heater capacity re- quired for a steam table, area of radiating surface, kind and thickness of lagging, nature of top surface, amount of water in reservoir, hours of use, and the maximum quantity of food warmed, should be taken into consideration. Water Heaters. — A supply of hot water for cook- ing, dish washing and various other purposes must always be provided in the hotel or restaurant kitchen. The subject of heating water electrically is taken up COMMERCIAL COOKING 79 more fully in another chapter, but it is well to keep in mind that the demand for hot water is usually much in excess of most chefs' or cooks' preliminary estimates. Frying Kettles. — Fat, oil, or lard is often required to be heated to a high temperature for preparing French fried potatoes, doughnuts, croquettes, and other foods. The Simplex frying kettle designed for heavy service has standard dimensions of 12-inch diameter and 5-inch depth. It has a maximum rated capacity simplex Frying Kettle. of 2400 watts and is provided with a three-heat con- trol switch. Larger sizes are sometimes manufactured for special work. Toasters. — Some provision for toasting bread evenly and quickly is required in all hotel and restau- rant kitchens. A high heat is required and the device must do the work rapidly, or the toast will be dry and hard. The General Electric radiant type toaster has a capacity of two, three, or six slices of toast, during the preparation of which 1350 watts, 1800 watts, and 80 ELECTRIC HEATING General Electric Hotel Toaster 3150 watts, respectively are connected. The sides, base, and back of the device are of sheet iron. The top and front are open. The heating coils, of which there are seven, are placed at each end and between the hinged wire racks that support the slices of bread. Each rack is separately hinged to facilitate the removel Hughes Hotel Toaster. or examination of individual slices. The Plughes toaster is of the oven type. The toast is placed on a rack measuring 8 inches by 18}^ inches and inserted within the sheet iron casing be- tween radiant type heating elements. The rated COMMERCIAL COOKING 81 capacity is 2 kilowatts. The outside dimensions of the device are 9^ inches wide, 19 inches deep, and 9 inches high. Sixteen slices of bread may be toasted at one time. As the operation is performed within the casing the heat is conserved to a marked extent. The Simplex toaster consists of an oblong fiat top griddle on which the bread is placed and provided with either one or two grids, hinged at the back, which are folded down upon the upper surface of the bread, Cutler-Hammer Coffee Urn. thereby toasting both sides of the slices simultane- ously. The device is made in two sizes. The smaller one is 10 inches by 12 inches and has a rated capacity of 1000 watts. The larger one is 12 inches by 18 inches and is rated at 1700 watts. Both sizes are equipped with three-heat switches and so connected that the bottom griddle may be heated separately for baking hot cakes and similar operations. The heating elements are of the enclosed sealed-in type. 82 ELECTRIC HEATING Coffee Urns. — Either immersion type or disc type elements may be used for heating coffee urns in a hotel or restaurant. Electrically heated urns of ten gallons capacity or larger, provided with heating units of either the immersion or disc type, are available. Some of these urns are of the single shell type, whereas others are double walled and thoroughly insulated. Some are of the spray type and others are equipped with stoneware crocks for holding the coffee. Simplex Hot Cake Griddle. The rated capacities of the standard single shell type urns vary from about 1200 watts for a two gal- lon size, to about 4500 watts for the ten gallon size. The double walled types are much to be preferred, however, on account of their higher operating effi- ciencies. It is often desirable to convert a fuel burning urn into an electrically heated device. This may be done, either by inserting an immersion heater of the proper design in the top, or by supporting a heating element against the bottom of the urn. Hot Cake and Frying Gridldes. — Flat top griddles for making hot cakes are available in many sizes and makes. The 18 inch by 24 inch Simplex flat top grid- dle has a rated capacity of 2800 watts, whereas the frying griddle of the same make has a rated capacity of 3300 watts. Frying griddles are a necessary adjunct to the modern hotel and restaurant kitchen. They are usually provided with raised edges. For quick frying COMMERCIAL COOKING 83 of eggs, steaks, and fish orders they are convenient. Operated on medium heat, the frying griddles may be used for making hot cakes. Simplex Frying- Griddle. Waffle Irons. — For making waffles the electrically heated device is much superior to those heated by fuel. Little grease is required. The waffles are evenly browned and very attractive and palatable. The Simplex waffle irons are made in two sizes, adaptable for making dther two or three 4^ in. waffles at a time, and of rated capacities of 770 watts and 1150 watts respectively. They are so designed Simplex Two-Section Waffle Iron. that the sections are connected in series when heating up and in parallel when the waffles are baking. This arrangement makes it possible to keep the elements moderately hot between operations, and very hot while the waffles are cooking. The elements are of the sealed-in type imbedded in the iron. The frame of the device is of heavy cast iron. Electric Bake Ovens. Extent of Use. — The electric bake oven is being used extensively and with marked success in a num- ber of western cities and towns as well as in some 84 ELECTRIC HEATING parts of the east. It combines efficiency, speed, econ- omy, and durability. It has found widest application in small bakeries, hotels, restaurants, and various institutions. The electric bake oven is a compara- tively new development, and its possibilities have but recently been realized. There is no doubt, but what it has a wide field of usefulness, and will eventually afford a desirable load for central stations throughout the country. Construction of Electric Ovens. — Electric ovens are usually constructed in the cabinet form, with from three to five decks or compartments built one above the other. This design is unlike the brick baker's oven which has only one deck but is somewhat similar to the ordinary portable gas oven. The exterior walls are generally made up of galvanized sheet iron and the space between the exterior and interior walls filled with a thick layer of mineral wool or some other heat resisting material. The capacities of ovens now in use vary from 30 to 500 one-pound loaves, with baking surfaces of from 10 to 160 square feet, and with heater capacities of from 4 to 65 kilowatts. The weights of these ovens vary from 700 to 10,000 pounds. They may usually be heated to the proper temperature for bread baking in from 40 to 60 minutes. There are two' common methods of heating elec- tric ovens, both of which have certain advantages. In the styles first placed on the market, the heating ele- ments were mounted below the lower deck, and the heat circulated upwards along the sides and interior walls which were so arranged as to properly distrib- ute the heat at each deck. The General Electric and Simplex ovens are made in this way. The Hughes bake oven, however, is heated by coils of resistance wire mounted between each deck, above the top deck, and below the bottom deck. Each element is con- trolled by a three-heat switch. The wattage of each element is a little greater than the one above it, and likewise, the front part of each deck is made some- what hotter than the back. These provisions are COMMERCIAL COOKING 85 necessary on account of the gradual rise of heat to the top, and because of the heat losses around the deck doors. Features of Electric Ovens. — The decks are ac- cessible through hinged drop doors. The standard height of deck is about eight inches but they may be made higher if necessary. Tile decks may be used for continuous or heavy baking. Ovens so equipped will require more time to heat up but will maintain the temperature to better advantage when they are finally heated. Ovens not provided with tile decks are usually furnished with drip pans. An accurate pyrometer for indicating the temper- ature should always be made a part of the oven equip- ment. This instrument will be an aid to economy of operation and a great convenience for the baker. Table I. — Simplex Bake Ovens. Sq. ft. Height Maximum No. 1-lb. No. of of Baking of Decks kw. No. Loaves. Decks. Surface. in Inches. Demand. 152 36 3 12 8 6 154 56 4 18 8 8 156 70 5 23 8 9 158 90 5 26 8 10 Simplex No. 156 Bake Oven. Simplex Ovens. — Four standard sized ovens, as shown in Table I, are made by the Simplex Company. The temperatures in the ovens are controlled by single 86 ELECTRIC HEATING three-heat switches, which are usually fastened to the wall. The heating elements are of the cast grid type mounted in the base. , General Electric Ovens. — Three standard ovens, as shown in Table II, are manufactured by the Gen- eral Electric Company. They are of the Blodgett type, General Electric Type D-46 Bake Oven. with grid resistance heating units fitted into the base. The temperature is controlled by a three-heat knife switch, which may be mounted in any convenient position. Table II. — General Electric Bake Ovens. No. Sq. ft of Dimensions of 1%-lb. No. of Baking Baking Comp. in Inches. Type. Loaves. Decks. Surface, Width. Depth. Height. D-44 30 3 11.74 28 20 6.75 D-46 56 4 21.11 38 20 6.75 D-47 84 4 31.66 38 30 6.75 Maximum kw. Demand. 13 Hughes Ovens. — Ten standard ovens, as shown in Table III, are made by the Hughes Company. The heating units are mounted between the decks, and each COMMERCIAL COOKING 87 set is controlled by a separate three-heat switch. These ovens may be manufactured for use with tile decks when desired. Hughes No. 200 Bake Oven. 88 ELECTRIC HEATING Cat. No. 150 175 200 215 220 250 300 315 400 415 No. 1-lb. Loaves. 30 40 63 84 126 168 192 252 378 504 Table III HiiKhes Sq. ft of No. of Depth. 3 Baking Surface. 10 13.5 20.75 27.75 41 54.5 61.5 82 121 161 Bake Oveus. Dimensions of Baking Comp. in Inches. Width. Depth. Height. 18 18 37 37 37 37 37 37 73 73 27 27 27 27 53 53 80 8(0 80 80 Maximum kw. Demand. 4 5 7.3 10 15 20 23.5 31 47 62 Advantages of Electric Ovens.— The many fea- tures of superiority of electric heat over fuel heat which apply in the use of electric ranges obviously attend its use in connection with electric baking ovens A baker's shop is ordinarily a hot, stuffy place because ( N E U C O ) ^ jmu \ L-' - -03 ifi Jm> fi. ' ^^^. — -WtoS ■'• 1 i If r^ Bir #., :;^ 1 £-,-__ ^c^ ; I L -J%i 'Neuco- No. 107 Bake Oven (Capacity 48 2-lb. Loaves ELECTRIC WATER HEATING 89 of the intense heat. Very little radiation of heat, however, is noticeable from the electric oven on account of its heavy insulation. The hand may be held against the outside with no discomfort after the oven has been in service several hours. Heat Regulation. — The heat regulation in an elec- tric oven is nearly perfect. It is an obvious advantage Hug-hes No. 300 Bake Oven, Installed in Bakery and Grocery, Norfolk, Va. to be able to obtain the desired temperature in an oven in a short period of time. This feature alone goes a long way toward insuring satisfactory results. With coal ovens it is necessary to have a contin- uous fire in order that they may be put in operation without delay. Sometimes only one or two batches of bread are baked during the night but the fire must be kept up to take care of the next day's business. The electric oven overcomes this objection as it can be heated quickly. If the oven is not used contin- uously it may be maintained at baking temperature on the low heat with one-quarter the maximum current consumption. 90 ELECTRIC HEATING Saving in Floor Space. — Only a fraction of the floor space is required for an electric oven that is necessary for a brick oven. The user of a brick oven, furthermore, must have a large space in front of his oven in which to manipulate his peel for inserting and removing material. Very small space for this pur- pose is required by the user of an electric oven. The use of coal ovens, moreover, makes it necessary to provide storage space for a large supply of fuel. Coal must also be paid for in advance and a considerable Hughes 500-Ijoaf Oven (Special Design). amount of money is tied up. No storage space, how- ever, is required for electric energy, and it is not paid for until used. When a new bakery is constructed it may be made of lighter material, because electric ovens weigh only a fraction as much as brick ovens. Sanitary Features of Electric Ovens. — Electric ovens are absolutely sanitary. The heat is derived from resistances operating at comparatively low tem- peratures. There are no fumes or objectionable odors such as are produced by gas ovens, to contend with. The dirt and dust always encountered with brick ovens are entirely obviated. The electric ovens may also be easily and quickly cleaned. COMMERCIAL COOKING 91 The fact that an electric oven is used in a place of business is an advertisement for the establishment. It carries an appeal to the public generally. Diversity of Baking. — All classes and kinds of bread, cake, cookies, pies, pie shells, patty shells, and rolls may be baked in the electric oven with the great- est satisfaction and ease, and at a very reasonable cost. Patty shells will attain the beautiful brown and flaky appearance in an electric oven without the use ot Ggg BK MIDNICKT """" Typical Load Curve Hughes Special 500-L.oaf Oven, Turning Out 560 141/^-oz. Loaves Every 45 Minutes. and butter mixtures that are usually required in other ovens. Bread, cake and pies will always have just the right shape and color. They will likewise remain fresh longer, as less moisture is removed from the product. A larger, better colored, finer textured, and thin- ner crusted loaf of bread can be produced in the elec- tric, than in the fuel oven. The light golden brown color of bread baked electrically will always increase the demand for the product. Cakes, cookies, etc., which require lower temper- atures than bread, can be baked after the bread is taken from the oven without using additional current, or they may be baked while the oven is heating up. Economy in Roasting Meats. — The great variety of food that may be prepared in an electric oven, makes 92 ELECTRIC HEATING it of considerable value for cafe, cafeteria, hotel, and restaurant use. All kinds of meats, including fish and fowl, may be roasted in an electric oven with less shrinkage than in any type of fuel oven. The shrink- age loss in fuel ovens varies from 30 to 40 per cent, whereas it is only from 15 to 20 per cent in the elec- tric oven. The meats will always be juicy, wholesome, clean, attractive, and delicious in flavor. No oxygen being consumed or poisonous gases being given off in the electric oven, the meats do not take on the hard, bitter tasting crust often apparent where fuel is used. In roasting chickens in the electric oven it is not necessary to spread a greased cloth over them to prevent the formation of hard crusts. They will be juicy and palatable if cooked in an open pan. Utilizing Stored Heat. — After the day's cooking is done, cereal, baked apples, baked pork and beans, spiced ham, etc., can be prepared in electric ovens without using any additional current. Simply place the materials in the oven. They will cook on the stored heat and be readv to serve for breakfast. CHAPTER VII ELECTRIC WATER HEATING. Hot Water a Necessity. — Enormous quantities of energy are constantly required for heating water. In the average home, more energy is used for heating water than for any other domestic purpose aside from that utilized in warming the air. In the industrial field, the operations that require hot water are almost without number. For generations the only way of heating water has been by fuel combustion methods whereby chemical energy stored in fuel is transformed into heat energy, which is in turn taken up by the water in amounts varying with the efficiency of the apparatus employed. Comparison of Fuel and Electricity. — As set forth in another chapter, most fuels, on the basis of actual cost of the two mediums, have a higher heating value than electricity. It is possible, however, to operate an electric water heater at a much higher efficiency than a fuel heater. If necessary, the electric heater may be immersed in the liquid itself, in which case practically all the heat generated must be imparted directly to the water. This is impossible with a fuel device which requires that external heat be applied. It is obvious that fuel heat generated on the outside of a tank must lose much useful energy through the chimney and the surrounding atmosphere. Although it should not be understood that elec- tricity for heating water can compete on a cost basis with the many cheap fuels that are available in most localities, it should be known that it is often possible to so design electrical installations that they will not be more expensive to operate than the less efficient fuel burning devices that are commonly used. This condi- tion is especially true with the smaller installations. 94 ELECTRIC HEATING In making comparisons between fuel and electric water heating methods, the many advantages of elec- tric operation, aside from the cost, should be consid- ered. Dirt, smoke, moisture, fumes, and excessive heat are obviated when the electric method is used. The dangers of fire and explosions are done away with. The care and attention required by fuel burning appa- CtRCvmriON TYPt HZMLR IMMEKSIOH TYP£ HEATER fTTANK^W: MldTFH CIRCULATION TYPE HEATEP 9 t fe ~ • I ^_i ] PRESSURE Ti*NK HEATER Typical Methods foi- Heating Water. ratus is eliminated and the only attention necessary is the turning on and ofif of the current. Some of the electric devices now being constructed are controlled automatically, and therefore demand no attention whatever. Thermal Characteristics of Water. — No other known liquid or solid has as high a specific heat as water. In other words, water has a greater capacity for storing heat energy than an equal weight of any liquid or solid raised an equal number of degrees in temperature. Its capacity for storing heat may be ELECTRIC WATER HEATING 95 considered analogous to that of a sponge for absorb- ing water. After the boiling point of water is reached, steam begins to be generated and unless the water is heated under pressure, it no longer continues to store energy, but gives off the heat with the same rapidity it is taken up. Water, like other liquids, is heated by convection currents set up within the substance itself. Very little of the heating is done by conduction between the indi- vidual particles of which it is composed. The con- vection currents are created by the difference in weight of hot and cold water. Whereas, at 32° F. water weighs 62.42 pounds per cubic foot, it only weighs 59.85 pounds at 212° F. It is this difference in weight that causes the top of a storage tank to become hot before the bottom, and which creates the circulation in the ordinary hot water heating system. Cutler-Hammer Instantaneous Water Heater. Electric Energy Required for Heating Water — Assuming the weight of water to be 8.3356 pounds per gallon it may be calculated that one kilowatt hour of electric energy will raise 409.33 gallons of water one degree F. or 4.0933 gallons 100° F. If a water heater of one kilowatt capacity be operated at 100 per cent efficiency it would accomplish the following results : 96 ELECTRIC HEATING Raise 409.33 gal. 1° F. in 1 hour and consumo 1 kvv.-hr Raise 8.19 gal. 50° F. in 1 hour and consumo 1 kw -hr ^'■^]^*^ „„ 4.09 gal. 100° F. in 1 hour and con.sunie 1 kw.-hr Raise 9823.9 gal. 1° F. in 24 hours and consume 24 kw -hr Raiso 196.48 gal. 50° F. in 24 hours and consume 24 kw"-hr* Raise 98.24 gal. 100° F. in 24 hours and consume 24 kw!-hr! For ordinary calculations, it is often convenient to remember that one kilowatt of capacity will raise about 100 gallons of water 100° F. in twenty-four hours. Westinghouse Disc Type Immersion Heater. Simplex Coil Type Immersion Heaters. Utilizing Waste Energy. — The energy utilized in heating water is expended in two ways. A certain per- centage is required to supply the losses of heat which take place on account of radiation, convection, and conduction from the heater, piping system, and stor- age tank. Energy, so expended, cannot be utilized in any other way and is entirely wasted. The balance of the heat energy generated may be called the useful energy, as it alone affords the user his supply of hot water. It is therefore apparent that every possible effort should be made to so design a water heating installation that the losses will be reduced to a mini- mum, and in that way utilize the waste energy. This purpose is usually accomplished by covering the pipes and tank with material of low heat conductivity — a process generally known as lagging. Heat Losses. — Authorities vary in their estimates of heat losses from metallic surfaces, between 1.5 and 3 B.t.u. per square foot per Fahrenheit degree differ- ELECTRIC WATER HEATING 97 ence in temperature per hour. The loss is naturally greater from dark, rough radiator surfaces than from the brighter and smoother ones of galvanized iron tanks and pipes. For ordinary water heating calcu- lations it has been found safe to figure a loss of 0.6 of a watt (approximately 2 B.t.u.) loss per square foot per Fahrenheit degree difference of temperature per hour. The tremendous amount of heat that is lost from surfaces of exposed water tanks and piping systems is seldom appreciated. It may be assumed, for in- stance, that a 24 gallon tank of water having an ex- posed area of 14 square feet, is to be maintained at a temperature of 100° F. above that of the surrounding atmosphere. The energy that would be required to maintain such a temperature, provided no water was drawn off, would be approximately : 14X .6X 100 = 840 watts. If this tank were heated with a one kilowatt heater there would be but 160 watts of the total capacity available for supplying hot water at the required tem- perature. In this instance, the energy produced by the 840 watts of the heater capacity would be lost and only 160 watts capacity utilized. Efficient Lagging Essential. — Had this tank been covered with some form of lagging material of low heat conductivity, having an efficiency of say 85 per cent, the capacity required to maintain the desired temperature would have been : 14 X .6 XlOO X 15% = 126 watts. It is thus apparent that the energy produced by only 126 watts capacity could be lost, whereas, the re- maining 874 watts capacity could be utilized for heat- ing water to the required temperature. The operating efficiency of the unlagged tank installation would be 16 per cent, whereas it would be 87.4 per cent efficient when lagged in the manner assumed. Table 1 indicates the number of gallons of water that can be delivered per day at a temperature 100° F. above that of the water supply and of the surround- 98 ELECTRIC HEATING ing atmosphere with various installations. The figures are based on the use of seven different standard sized tanks and six different capacity heaters. The daily output is computed, first with the tanks unlagged, second with a 50 per cent efficient covering applied, and third with an 80 per cent efficient covering applied. Other losses than those from the surfaces of the tanks are not considered. J. M. Magnesia Sectional Pipe Covering. TABLE 1. Gallons of Water per day — 100° F. Temperature Rise. -.^^ Tank Dimensions and Capacities. * "1 J? Gallons Capacity . 18 24 30 40 66 82 100 ^^ Dimensions... . . . . 12"x3 ' 21"x4 l'12"x5' 14"x5' 18"x5' 20"x5' 22"x5 ^O.S Area in Sq. F1 . . . 11 14 17.25 21.3 27 30.5 34 Unlagged . . 9 750 Lagged 50% Eff.' 42 33 23 ii . . Lagged 80% Eff. 62 58 54 49 43 38 34 Unlagged . . 34 16 1000 Lagged 50% Eff'. 67 58 48 36 i9 '9 Lagged 80% Efe. 88 83 79 74 68 63 59 Unlagged . . 84 66 46 22 1500 Lagged 50% Efe'. 117 108 98 86 69 58 48 Lagged 80% Eff. 137 133 129 124 118 113 109 Unlagged . . 116 97 72 38 17 2000 Lagged 50% Efc'. 158 148 136 119 109 98 Lagged 80% Eff. 183 179 174 168 163 159 Unlagged . . 197 172 138 117 96 3000 Lagged 50% Eff. 248 236 219 209 198 Lagged 80% Eff. 279 274 268 263 259 Unlagged . . 372 338 317 296 5000 Lagged 50% Eff'. 436 419 408 398 Lagged 807c Eff. 474 468 463 459 Methods of Heating Water Electrically. — There are two general methods of heating water that have come into general use — the instantaneous method and ELECTRIC WATER HEATING 99 the thermal storage method. The former makes use of special devices which heat the water as it passes from the faucet and which are not connected at other times. The latter method, as the name implies, is used \ United Sales Hot Water Faucet. 100 ELECTRIC HEATING for heating water and storing it for future use in a tank or reservoir. Two types of heating devices are commonly used with thermal storage systems — the immersion type, and the circulation type. The former is usually in- serted in the tank, whereas the latter is connected with pipes outside the tank. Instaiitaneous Water Heating. — Devices for this class of service are usually made to attach to the ordi- nary water faucet. They are convenient for many pur- poses where only small quantities of hot water are needed. As it is possible for one kilowatt to heat only about 4 gallons of water 100° F. per hour, their use is naturally somewhat limited. The load which they create is often considered undesirable on account of the high demand and relatively low energy consump- tion. Instantaneous heaters are usually made with a resistance coil around which the water circulates, and which is connected when the faucet is opened. Another device, however, consists of a hollow cylinder and core of graphite. When the water flows around the core inside the cylinder it acts as a conductor and the flow of current set up causes heat to be generated in the water itself. In other words, the water is heated in the same way as in the common water rheostat. Thermal Storage Water Heating. — The thermal storage method is more often employed than the in- stantaneous method. The equipment must consist of at least two essential parts — a water heater and a containing vessel for storing the water after it is heated. With an equipment of this kind the user may store up a large quantity of hot water slowly and draw it ofif as rapidly as he wishes when it becomes heated. The load created by this kind of a heater is desirable on account of its low demand and relatively high energy consumption. It is apparent, on the other hand, that such equipments are necessarily wasteful of energy unless the heat stored in the water is con- served. ELECTRIC WATER HEATING 101 Immersion Type Heaters. — The heating of water or other liquids is accomplished with these devices, by the insertion of resistance elements in them. Many types of immersion heaters have been developed. Some Hatl^tti-rioi, roMOT wAreit ^Auetf MUST BC TA.KCNrifOM TOP or r eOL o wA Ten HCJ Supply p'ps Apfel Immersion Tank Heater. Coin Circulation Tank Heater. consist of open coils and others of hermetically sealed tubes. Some are constructed for use in open vessels, and others are provided with fittings for attaching them to closed tanks. 102 ELECTRIC HEATING The essential advantage of this type of heater, for thermal storage water heating, is that the device must give off practically all its heat to the liquid. En- ergy can only be dissipated indirectly from the water and surface of the containing vessel or directly by con- duction through the metallic fiittings. Circulation Type Heaters. — It is customary, though not essential, to mount a circulation type heater outside the tank or reservoir. A pipe leading Westinghouse Circulation Heater. Westinghouse Immersion Heater. from the bottom of the containing vessel carries the colder water to the heater. As the water becomes hot- ter it rises through another pipe connected to the top of the containing vessel. This process continues, re- gardless of whether any pressure is applied, until all the water is heated. Circulation heaters are available in many styles, forms, and sizes. The Westinghouse heater consists essentially of a waterproof bayonet element, inserted in a metal casing, and designed so that the water cir- culates around the heating element inside the casing. The Simplex, General Electric, and many other types of circulation heaters, are made up of resistance wire ELECTRIC WATER HEATING 103 wound around hollow tubes through which the water passes. The Coin Machine heater is of the induction type, and so designed that the passage of current through copper wires surrounding an iron core creates eddy currents in the iron and causes it to heat. The advantages of the induction type heater over the re- sistance types are its rugged construction and its capacity for running dry without burning out when the water supply is cut off. The present designs of induction heaters, however, create a relatively low power factor load, averaging about 80 per cent. The attractive features about the circulation type heaters are the ease with which they may be attached to any tank or containing vessel, and the facility with which they may be removed for repairing or cleaning. The water, furthermore, is delivered to the top of the tank as it is heated and is soon ready for use even though only a portion of the tank may be heated when the water is wanted. The great disadvantage is the extra radiating surface the heaters and pipes present, and the additional, though relatively small, heat losses that must inevitably result. Essential Features of a Water Heater. — A device of this character should be durable, easily removed for cleaning or repairing, and readily controlled. The surface exposed to the air should be of small area or thoroughly insulated from heat losses. The rela- tive area of the heating surface exposed to the water should be large in proportion to the wattage of the heater. Air bubbles and deposits will inevitably col- lect if the heating element is operated at a high tem- perature. The amount of scale which forms inside the heater varies widely in different localities, and de- pends upon the amount of salts in solution. The scale may be chipped off or removed with a dilute solution of hydrochloric acid. In either the instantaneous or circu- lation type heaters, it is generally best to have the water passage quite large, so that sediment or deposits will not obstruct the flow. It is sometimes desirable to restrict the flow of water through a circulation heater in order that it may rise to a higher temperature as it 104 ELECTRIC HEATING passes. This may be done by making the passageway smaller or by mounting the heater somewhat higher than the bottom of the tank. Water heaters that cre- ate low demands and are required for long hour use are generally considered more desirable load builders than those constructed for high demands and short hour use. Automatic Temperature Control Devices. — Where it is desirable to keep a supply of hot water available for use at any and all times or to maintain water at a certain temperature for various purposes, automatic temperature control devices have a wide field of appli- cation. Electrical apparatus lends itself particularly well to automatic control, but the possibilities it natur- ally affords are as yet little understood. Any device of this kind that will cut off the current supply imme- diately a certain predetermined temperature is attained will be a wonderful convenience, and a great econ- omizer of energy. Its general application cannot but improve the diversity factor of central station loads. Devices of this character should be simple, durable, easily repaired, and readily adjusted. Performance Curves Therm Elect Water Heater. Temperature and Load Regulation, 24 hrs. ELECTRIC WATER HEATING 105 Explanation of Temperatures and I^oad Regulation CurveH of Tlierm-Eleet lo(M)-watt Water Heater. The above curves were plotted from observations taken on the 24-hour operation of a 1500-watt tihermally-controlled Therm-Elect Immersion Heater installed in a standard 30-gal- lon kitchen boiler. The heavy black lines extending- from the top of the chart are a graphic representation of the hot water duty-cycle im- posed upon the heating system in a liousehold using 100 gallons of 116 degree F. water per day. The length of each line is in proportion to tlie gallons of water drawn at the time indicated by its position; covering the day from the preparation of breakfast at 6:30 a. m. through the bathing period from 9 to 10 p. m. The curve in the center of the chart indicates the tempera- ture regulation of the water drawn from the tank, and rep- resents a regulation of 95 per cent for the immersion heater. The load curve produced by the six-point thermal control is shown at the bottom of the page, with its peaks at 10 a. m., 3 p. m. and at 10 p. m., and its valleys at 6 a. m., 12 noon and 6 p. m., indicating the diversity which would be obtained with respect to a cooking load operating in combination wUh the thermally-controlled water-heater. Automatic Time Control Devices. — Many com- panies are in position to supply energy during off peak hours at lower rates than during the period of maxi- mum load. The building up of such loads by means of thermal storage water heating apparatus, operated with time control devices, has probably not been given the attention heretofore that it will receive in the future. The loads that could be created would prove enormous. An equipment of this kind naturally requires larger water storage facilities than one that may be supplied with energy at any and all times. The addi- tional storage necessary will depend on the number of hours during which the energy will not be avail- able and upon the quantity and temperature of the water needed. Average Hot Water Requirements. — Many indi- viduals have little conception of the amount of hot water required for either domestic or commercial pur- poses. It should be clearly understood that when 30 gallons of water at 150° F. is mixed with an equal quantity at 50° F. the temperature of the 60 gallons will be 100° F. The temperature of bath water is usually about 98° F., whereas 120° F. is scalding tem- perature. It is therefore apparent that if a relatively 106 ELECTRIC HEATING 'Therm Elect" Immersion Heater and Thermostat. Hughes Circulation Heater Applied to Tank. ELECTRIC WATER HEATING 107 small quantity of water is heated to a high tempera- ture, it will afford a considerably larger amount when diluted with cold water for ordinary use. The hot water requirements of hotels, restaurants, barber shops, Good Housekeeping- Automatic Temperature Conti'ol Circulation Watei- Heater. and other commercial users is generally underes- timated, and it is advisable to give each proposed in- stallation careful preliminary consideration. Installation of Thermal Storage Water Heaters. Correct Plumbing Essential. — The relative posi- tion of the tank and heater, the connections between the two, the size of tank and pipe used, the elimina- tion of air pockets, and many other plumbing features are worthy of serious consideration when a thermal storage water heating system is installed. The tank used with equipments operated under pressure should 1)e mounted vertically to insure maxi- mum difference in temperature between the top and 108 ELECTRIC HEATING bottom, to obviate mixing the hot and cold water when the supply is drawn off rapidly, and to create better circulation of water through the heater. Standard tanks are usually fitted with two taps at the top. The tap used for connecting the tank to a water main should be provided with an inside pipe connection so that the cold water will be delivered to within a few inches of the bottom. It is necessary to have a very small hole drilled in this vertical pipe near the top of the tank to prevent the water being drawn out by syphonage whenever a hot water faucet is located below the level of the tank and a possibility exists of the pressure being withdrawn. Instances of where this precaution is necessary are often found in country residences when the domestic water supply is furnished from a pressure or storage tank. It is obvious that if the water is syphoned out of the water tank the heater will become dry and possibly burn out. Installation of the Heater. — Immersion type heat- ers are usually, though not necessarily, inserted in the bottom of the tank. Circulation type heaters should be installed as close to the storage tank as pos- sible. Better circulation will obtain if they are mounted vertically, and in such a position that the lower portion of the heating element will not be higher than the bottom of the tank. Rapid circulation is not always desirable, however, as the water passing through may not take up enough heat to produce the desired difference in temperature between the top and bottom of the tank. Pipe Connections. — Circulation type heaters should be connected with pipe unions to permit of their quick and easy removal for inspection, cleaning, or repairing. Unless an electric heater is of extremely large capacity in proportion to the size of the storage tank, its upper end should be connected either to the hot water out- let or to a special tap near the top of the tank, rather than to the standard side outlet usually provided. If the hot water coming from the heater is delivered at or near the top, rather than at the side, it will be found that the circulation will be better and that a quantity ELECTRIC WATER HEATING 109 of hot water can be drawn from the tank much more quickly than otherwise. By-Passing. — The pipe connections at the top of the tank should be carefully arranged. The hot water distribution pipe should lead straight out of the tank, and the connection from the heater should connect to Epco Immersion Heater showing Application to Tank. it from the side as close to the tank as possible. If this precaution is not taken the water drawn out through the distribution pipes may come partially from the top 110 ELECTRIC HEATING of the tank and partially from the bottom on account of the rapid suction of cold water through the heater. The action produced is somewhat similar to that in an ordinary atomizer and is called by-passing. Some manufacturers recommend the use of special "non- by-pass tees" to entirely obviate this difficulty. Air Pockets. — Unless the plumbing is properly done and the hot water distribution pipes are free from air pockets, unsatisfactory operation is likely to be Cutler-Hammer Circulation and Immersion Type Heaters showing- Form of Heating Elements. charged to the electric heater. Air pockets are formed when the water is carried up and finally deliv- ered at a lower point. The air gradually collects at the highest point and prevents the passage of water. The only relief from such a condition is the placing of an air cock at the highest point, or a rearrangement of the piping system. Design of Distribution System. — The arrangement should be such that the storage tank will be situated I I I ELECTRIC WATER HEATING 111 as near as possible to the central point of distribution. Connections between the tank and faucets should be made by the shortest routes, and the pipes should not be larger than is absolutely necessary for satisfactory service. The longer and larger the pipes that are used, the greater will be the loss through radiation from their surfaces. So-called ''return systems," wherein hot water is allowed to circulate continuously from the top of the tank, through the distribution pipes, and back to the bottom of the tank, will be found to require much more energy for their operation than ordinary systems, on account of the constant heat losses that take place from the surface of the pipes. Storage Tank and Pipe Lagging. — As heretofore suggested the proper lagging of tanks and piping sys- tems is often of as much importance as provision for adequate heater capacity. The kind of material em- ployed should be carefully considered and the most approved methods of application adopted. Unless good lagging is used and properly applied, the oper- ating efficiencies of the heating system may be greatly impaired. A few of the commonly known types of lagging materials are described and the methods of application outlined. Keystone Tank Cover. — This form of lagging con- sists of a % in. layer of compressed hair felt having an asbestos lining, and a canvas cover. Experiments show that this form of lagging will prevent at least 50 per cent of the usual radiation losses from the sides of an exposed tank. Keystone covers should be laced tightly. The upper edge of the cover should be allowed to project at least half an inch above the side edges of the tank. The top of the tank should then be covered with a half- inch layer of cement and pasted over with six-ounce drill. Economy Tank Covers. — The Johns-Manville Economy tank covers are made up olf 1 in. hair felt lined with asbestos and covered with a canvas jacket. They are designed to hit the standard water tanks. The top 112 ELECTRIC HEATING and sides are in one piece and may be laced tightly around the tank. A rope wrapped temporarily about the jacket will hold it in place and make the lacing much easier. When the tank is exposed the canvas jacket should have a coat of sizing and be painted with two coats of cold water paint or lead and oil. or WATER SERVICE Pipe TOP conNEcrioH eilTHCR TOSERVIce. flPZ on Tt^HK simplex Heater and Stand- ard Pipe Connections. Economy Covering Applied to Tank and Pipes. The manufacturers claim an efficiency for this form of lagging of from 85 per cent to 90 per cent. Although Economy covers cost about twice as much as Keystone covers the increased savings which they effect warrant their use. ELECTRIC WATER HEATING 113 Directions for Lacing Tank Covers. — Start lacing at the top of the cover. Tie the end of the lace to the right hand eyelet and thread it over to the oppo- site eyelet. Make two loops and then lace diagonally under the cover to the eyelet below the first and make two loops. Repeat the process until the last pair of eyelets is reached and then make three loops. Lace one of these loops back and tie it to the lace end by means of a bowknot beneath the cover. Block Lagging. — Many forms of heat insulating blocks for lagging the larger sized tanks are available. One inch thickness is usually recommended for water tanks and the insulating efficiencies may be figured at from 80 per c,ent to 90 per cent depending upon the material used and the care with which it is applied. The blocks usually come in strips about 6 in. wide and 3 ft. long. For lagging the sides of a small tank the blocks are usually cut in strips about 3 in. in width so that they will more nearly conform with the surface con- tour. These strips are then placed around and length- wise of the tank and held in position temporarily with a small rope. The blocks are allowed to project about 1^ in. over each end of the tank to conform with the top and bottom lagging. Soft annealed wire (about No. 16 gauge) is then wound around the blocks and tightened up so as to hold them firmly in place. The blocks are then beaten down into shape with a wood paddle or mallet so that no air passages may be left between the covering and the tank. Cement is then mixed with water to about the con- sistency of ordinary mortar and applied to the outside about y2 in. in thickness by means of a trowel. All cracks and crevices should be filled, and the surface made smooth and even. A six-ounce drill jacket is then pasted on the outside. Flour and water may be used for paste. The salvage edges of the drill should be torn off, before it is dipped in the paste, to prevent puckering. The ends of the tank ar^ usually lagged with small blocks wired in position (when possible), pounded 114 ELECTRIC HEATING down, coated with cement and a drill cover pasted on in a similar way to that suggested for the sides. When the tank is convex at the bottom or so mounted that the blocks cannot be placed in position, a coating of soft cement is put on the surface of the tank first. The blocks will then adhere to the outside while the next coating of cement is trowelled over them and the covering is put in place. Pipe Lagging. — A large variety of coverings are available for lagging pipes and fittings. Sectional pipe covering which may be hinged over, pasted together by means of a lap in the canvas jacket, and held secure with brass bands, is most commonly used. It may be secured in thicknesses varying from ^ to 3 inches, but for water piping, 1 in. thickness is ample. It is usually made up in 3 ft. lengths. The savings in heat that may be effected by the careful lagging of pipes and fit- tings are enormous. Fifty feet of 1 in. pipe for in- stance, has approximately the same area as a thirty gallon tank, and filled with water at the same temper- ture, will radiate heat just as rapidly. It is of the utmost importance that the pipe leading from the heater to the top of the tank should be lagged when water is heated by the circulation method. The water circulates constantly in this portion of the sys- tem as long as the heater is in service. J. M. Asbestocel Sectional Pipe Covering". CHAPTER VIII ELECTRIC HEATING OF BUILDINGS. Use and Advantages. — Were it possible to heat buildings with electricity at no greater cost than with combustion methods, it would be only a matter of time until they would all be heated electrically on account of the many superior advantages aflforded. The pres- ent high cost of generating and distributing electric energy, however, precludes its universal application as a substitute for fuel heat. It is only in localities where fuel is very costly, or where electricity may be used for heating during off-peak seasons or oflf-peak hours, that extensive use may be made of it as an Westinghouse Convection Heater. air heating medium. In some sections of the west, where water power is used extensively for irrigation pumping in the summer, it has been applied during the winter season to the heating of buildings with con- siderable success. The energy so used, which might otherwise be wasted, is turned into a useful by-product and sold at a low rate in competition with coal and other fuels, at the same time netting the central sta- tions a small profit. 116 ELECTRIC HEATING Some attention has also been given to the devel- opment of electric heating systems designed to make use of the great heat storage capacity of water, and so arranged as to heat large quantities of it during off- peak hours for use in warming buildings. Where con- ditions are favorable this method should find a wide application. In a general way it may be stated that electric energy is too costly to compete with ordinary fuels, but where the cost of heating a building is a relatively unimportant item in comparison with the desire for General Electric Convection Heater. Majestic Radiant Heater. convenience, it is certain to meet with favor. For heating small offices, bath rooms, sick rooms, cold cor- ners, and for taking the chill out of the air during mild weather its use is ideal. Electricity has the peculiar advantage of being instantly available, and regulated at will. It neither destroys oxygen nor vitiates the atmosphere. It is the cleanest and safest known method of heating. Among the advantages of electric heaters, are ease of instal- lation, simplicity of operation, portability, flexibility of location, and small floor space required. There are certain customers in nearly every locality that are willing to pay for the luxury afforded by electric heat, regardless of its cost, provided its ad- ELECTRIC HEATING OF BUILDINGS 117 vantages are made known to them. These individuals, in most instances, may be readily singled out and de- sirable business secured with little effort. Comparative Cost of Fuel and Electric Heat. — It should be understood that electric air radiators always operate at 100 per cent efficiency, whereas coal and gas apparatus may often operate at efficiencies as low as 10 per cent. By referring to the comparison of costs of fuel and electric heat set forth in Chapter I, it will be noted that 600 B.t.u. gas at $1.00 per thousand cubic feet operating at 20 per cent efficiency is about equiv- alent to electricity at 3 cents per kilowatt hour. Hughes Convection Heater. Electric Heating Systems. — A large variety of sys- tems of electric heating are in use, but few data are available to show their relative efficiencies and merits. On the assumption that the application of electricity to the heating of air is 100 per cent efficient, it is obvious that the essential feature to be considered with each system is the proper distribution of the heated 118 ELECTRIC HEATING air. If the heat is intense near the heater or radiator and other parts' of the room are cold the results will not be satisfactory. It is essential, therefore, that the system employed should not only heat the air but should set up convection currents that will serve to distribute it. The size, type, operating temperature, and design of the heaters have much to do with this par- ticular feature. The commonly known methods of electric heating are (1) by radiant heaters, (2) by convection heaters, (3) by oil and water radiators, (4) by indirect air heat- ing systems, and (5) by steam and hot water circula- tion systems. Radiant Heaters. — Radiant or Idilminous type heat- ers are made in a variety of styles and sizes. The heat- Estate Convection Heater. ELECTRIC HEATING OF BUILDINGS 119 ing elements may consist of coils of exposed wire or filaments within glass globes, which are heated to a glowing temperature. The units are usually mounted in front of polished reflectors which focus the heat in any desired direction. Some radiant heaters are man- Westinghouse Flush Type Radiant Heater. ufactured in small portable sizes, whereas others are made for use in open fireplaces or for flush wall mounting. The heat from glower type radiators is like sun- shine in that it only raises the temperature of a body which is opaque to heat waves. It passes through the air without heating it perceptibly, and only causes a rise of temperature in the air by heating objects that offer opposition to its passage, these objects in turn heating the air in contact with them by conduction. Heat waves are unaffected by air currents and glower type radiators are therefore convenient for warming portions of the body or for warming a person in a large open space. The light, cosy glow which they 120 ELECTRIC HEATING emit makes these heaters very attractive and cheerful in the home or office. It is often thought that a glow type radiator, in front of which it is uncomfortable to hold one's hands, must be emitting more heat than a resistance type, over which they may be held for any length of time \miii r^Jf €^ ^ nsa^ '"-^^ Hot Point Radiant Heater. without any sense of discomfort. This impression is wrong, because all the energy delivered to any elec- tric heater, regardless of the type, is transformed into heat energy. The glower type heater concentrates the heat by means of polished reflectors, while the resistor type distributes the heat through the air. Uni- form temperature throughout a room cannot readily be attained with a glower type heater. Convection Heaters. — Heaters of this type are also manufactured in a variety of sizes and capacities. They usually consist of coils of resistance wires or ribbons mounted on ornamental frames, surrounded with a sheet metal or cast iron casing, with openings above and below to permit the free passage of air through the coils. The elements are generally designed for opera- tion at temperatures below the red heat. The warmth generated by this type of heater is transferred to the air bv direct contact with the hot resistance elements ELECTRIC HEATING OF BUILDINGS 121 and the surface of the heater. Convection currents are consequently set up which tend to equalize the room temperature. Much depends upon the design of this type of heater, if proper heat distribution is to be attained. The construction should be such as to develop ample circulation of air through the heated coils. Convection heaters should never be mounted flush with the walls. They should be set a short distance away from the sides of a room. Where this is im- possible, guards should be mounted on top of the heat- ers to deflect the heated air toward the center of the Simplex Convection Heater. room. The tops of the heaters should be unobstructed in order to permit free passage of air. Two or more small heaters will always be found to give a better dis- tribution of heat than a single large one. Heaters placed under windows will warm the air admitted to a room and tend to obviate unpleasant draughts. Con- vection heaters in capacities larger than 750 watts are usually provided with three-heat switches to permit operation at lower temperatures during mild weather. Oil and Water Radiators. — A large number of oil and water radiators have been placed upon the market. They are usually made in the form of ordinary hot water radiators with the heating elements inserted in 122 ELECTRIC HEATING the sides and immersed in liquids. Their chief advan- tage IS in the greater radiating surface which they offer to the air in comparison with ordinary convection air heaters. The heating elements being submerged in the liquid operate at low temperatures and are less subject Hot Point Convection Heater. to oxidation. The water or oil which is used holds the heat for a considerable time after the current is shut off. The oil radiators may be operated at a higher temperature than the water radiators because oil vapor- izes at higher temperatures. The disadvantages of this type of heater are the slowness with which it heats up, its greater weight and lack of portability, and its higher manufacturing cost, in comparison with convection heaters. Indirect Air Heaters. — Radiators which are used to heat the air in a passage or flue which supplies air to a room are called indirect heaters. The radiators may consist of coils of wire or cast grid resistance mounted on a frame work so as to allow free passage of air and placed in a chamber or box at the foot of vertical flues leading to the rooms to be heated. Air is ad- mitted to the chamber from the outside, and after passing through the heated resistance, it is taken directly into the flue. Ventilating fans may be inter- posed between the heating chamber and the outside in order to increase the volume of air. Installations of this character in individual capacities of several hundred kilowatts have been in ELECTRIC HEATING OF BUILDINGS 123 successful service for a number of years. The chief advantages have been found to be a marked saving in floor space, ease of operation, cleanliness, and lack of attention required. Steam and Hot Water Systems. — Electrically heated steam and hot water systems are similar in every respect to ordinary fuel burning equipment, except that electric steam boilers and water heaters are substituted. A number of installations have been made which have proved very satisfactory. The chief advantages are even heat distribution, ease of operation, freedom from dirt, soot, and ashes, and Apfel Water Radiator. less attention required. It is apparent, however, that unless buildings are already equipped with steam or hot water heating systems, the cost of installation will be considerable greater than for direct air heating systems. Installation of Electric Heaters. — The use of nu- merous small heaters of three kilowatts capacity or less, each provided with three-heat switches, creates a better diversity of load for the central station than a few large single heat heaters. Many concerns require that buildings wired for electric heating shall be provided with 220 volt serv- ice in order to prevent the use of lights and lamp socket devices on special heating circuits. Such pro- 124 ELECTRIC HEATING vision has the further advantages of reducing the costs of wiring and service connections and producing better balanced load conditions. In making installations of electric heaters of all types every facility should be provided for convenient operation, otherwise the habit of opening windows, rather than turning off the current when the room be- comes too warm, will be encouraged. Calculation of Heat Requirements. — The energy needed to heat a building or an individual room is the sum of the heat required to warm the air for proper Radiator with Coin Circulation Water Heater Attaclied. ventilation and that which is transmitted to the out- side and lost. The former varies with the use for which the building is required, and the latter with the nature of its construction, exposure, etc. They both vary with the difference in temperature between the outside and inside of the buildings. The two most commonly known ways of calcu- lating the heat requirements of a building are (1) by ELECTRIC HEATING OF BUILDINGS 125 the use of the "B.t.u. method" and (2) by the appli- cation of an empirical formula. We shall call the B.t.u. method, the "watt method" because, for con- venience, all calculations will be made with watts rather than with British thermal units. The watt method is naturally more accurate, whereas the em- pirical formula is easier handled. The empirical form- ula is based on the watt method but is more general in its application. It is convenient for making prelim- inary estimates. Watt Method. — Calculation based on this method take into account the heat in watts (1) to heat the air required for ventilation as well as the air which leaks around windows, doors, and various crevices ; (2) to supply the losses by transmission of heat to the out- side through the walls, window^s, floors, and ceilings. The sum of the watts required by a building for heat- ing the air and for supplying the losses will determine the heater capacities. Heat Absorbed by Air. — One cubic foot of air will absorb approximately 0.0054 watts per hour per degree Fahrenheit diflference in temperature. In order to determine the amount of heat required for heating the atmosphere inside a building, it is necessary to multiply the number of cubic feet of air per hour admitted to the building by the difiference between the outside temperature and that required within, and by the constant 0.0054. i.e., quantity of air X temperature difference X 0.0054 = watts per hour. The quantity of air admitted to a building de- pends upon (1) the ventilation required, and (2) the air leakage. Ventilation requirements may be fixed by law for some classes of buildings and for others the amount is usually fixed by the architects' judg- ment. The character and habits of the people living in a building also have much to do with its ventila- tion. The following table gives a fair average of the amount of air that is usually required for various kinds of buildings : i2§ WUDCme HKAIiNO Atnt^mmj^ Hn>i\n, ,.,,.,.,,,,, ,, %tfm m, ft, pt^r nf^i, Vki4ftvri*ftt ttm workuptvn, , I ., i»fi|(» ««, ti, vt*r pfrmoft, (hf lAviim rttftmn,, <*vo n>ii,\,\: , « x/t^r hour (a) MftJJw (¥if\iU ttpt»u «ffl>rw«vc/ thrtx? itfUtp^^m t'hutiitfp* pt't' fitmr. H««t Lo«t by Tftniml»»iofi.— The ♦^ tn- 1,-- t,r«r irjwftf© /r^t of iUffftce per Fttlif^tilidt dcK" ' i"' ' > ' ' hi ti^wpeffttiffe^ between \ hnjld- ifigM a»nl roonii, a>» >»et fr^fth in the »foll(>wing tabic, »€effli to b« pretty well ei^tabliwhed by the beit an th(/fitieM; 4--iU(ih hrU'H Wttll, ,,,,,,,,.,» t .,,,,,,,., i ^>iU Wtttt* if--iff^h itrU'U wt*i], ,,,,,, 1 1 II I mm, til,, O.iH wnitn ii-'iw'U init'H w»^i, ,11, ,,,,,,,,, ,,,,,t,ti #/#|| WAii« ^di i»»/i, htittk whli, .,,,,,,,,,,,,,,,,,,,,, 0Mfi WttHM ' 1 iUifuff^iii wt^Uti,,,,,,,,,,,,,,, i,i n hi'>' ■'•♦« //ftJJw ,,/,;,///,,,/,/!#//,*////» 1.6 * bfh ■ milt »>oH* Hin**n ,,,,,,,,,,,,,,,,,,,,,,,,,, 0,100 wnffw l-'i/K'h woort i»ttf(H|ott ,///,// #11 //,/*«/» O.iaio wititi* WuhfSttu HmmfiM (aotih\t§ h^^mi,,,,,,,,, 9M wtttm ti'\tt*prou( rtof/f'fn^, ,,,,,,,,,,,,,,,,,,,,,, 0,080 Wfltt« r>JM tinnthm, ,.,..,, t, ,,,>,,,,,,,>, ill, , 9,999 Witiifimt ('f\uiipS' ,, i ,,,,,, 1 1 ,,,, i , t ,,,.,, , 0,051 H«w»^r»«f| #<^inH«f (fiff pfmr ft|»«v») ,,,,,, , Mf4 Wo/'fl*-** «'*«ll)«Mw tmrief Ifon ro§t,,,,,,,, 0,060 w«tt« irhfpi'itur ('niiffiffn ,,.,,,,,,,,,,,,,,,,,,, 0,04* wtttfx Wo<>f1uH rtoof :,.,,,,,,,,,,,,,,,,,,,,,,,, 0,1|0 WttttM poo»' {«/» whun, J/» inftM,,,,,,,,,, /,,,«, 0,170 wflttN plf««l** wifinow «|tt»B, ,,,,,,,,,,,,,,,,/!, O;»00 w«(t« hoHf>l«i wlfjflow ^)»«i,,,,, /,,,,,,,,,«,,,, 0,170 WrtttN HIh«I«< ««k>')lMht , , / , , ( r I > f I f I , > , , I , , , < / / / / 0/96^ WKtiM /»<*HlH*i nky\\^tM,,,,,,,,,,,,,,,,,,,,,, ,, , 0,1»6 wflii* To obttthi th« Witti loMt by int»iHiiiJf4^ir>fi, multiply the Hft?tt« of the respeetlve surfflceft, by the tctiipera- ture (llfferenee between the exterior and the ititerior of the bulldlnii or roofn, and by the wattafi^e eon«tant» In the above table. I.e., area X temperature diflference X ceoitant *«watt» tfanwmjtted. Air Ltikift.-=^A careftil cofi>»ideration of air leak- age l» of ai mvieh Importance In the de»i|(n of heating Initallations a» 1m that of ventilation, The lo§»eg of heat on at'eonnt of air leakage eannot be ealenlated readily, and are nMually estimated. Air leakage dimply \\\ AuuMu\u vATvwvis wi\h rtiw ^iit*. Willi |«t^> j\^Ae^ mM h^vU^ wiM \NU\^h s\a\ \\\a\\ on n ^ ov \v>on\, aopon*! lo a ^ft^XtV tWtWX \\]M\\\ \\\t AX\^ oi «^\|Hv^cvl \V;%U?i UUW WJHVW M\>i' \Mh<^r (t^u\r« *\t ih!;;m})!id m ^!<^;;fmM Principle of Spot Welding. (Heavy current and sure applied between A and B cause the metallic plates to heat up and weld at the point of applica- tion as shown.) with sufficient pressure to cause them to adhere. This is usually known as the Thomson system. Alternating current of low voltage, (usually from 3 to 5 volts), is employed in resistance welding. The work is ordinarily done rapidly, because heavy cur- rents and high pressures may be applied. ELECTRIC WELDING 207 Resistance Welding Apparatus. — The equipment for electric resistance welding requires machines espe- cially adapted to the work in hand. The frame is usually provided with a clamping device for holding the parts, and a means for applying pressure after they have been heated. A transformer for reducing the voltage on the circuit, together with a main con- trol switch, and some means of regulating the flow of current, are ordinarily supplied with the machine. Manufacturing Applications. — Resistance welding is limited almost exclusively to new work of moderate Winfield S-12 Spot Welder. 208 ELECTRIC HEATING size. Practically every kind of metal, and many alloys and combinations of metals may be welded, if the sur- faces can be joined and the parts manipulated in the machines. A few of the many applications of resistance weld- ing apparatus are as follows : Wire Rings, Flat Hoop, Small Carriage Tire and Steel Cylinder Welded With a Thomson Welder. I ELECTRIC WELDING 209 Rail bonds. Wagon tires. Iron beds. Automobile parts. Shovels. Wheelbarrow bodies. Structural iron work.Iron wheels. Cooking utensils. Pipes. Typewriter parts. Chains. Screens. Stove pipe Valve heads. Axles. Steel shelves. Knives. Umbrella rods. Steel lockers. Boilers. Sheaves. Classification of Resistamce Welds. — The original method was known as butt welding, and consisted in bringing the pieces together either end wise or edge wise. After they became heated they were forced to- gether. A process known as spot welding was after- wards developed for welding lapped joints. It was accomplished by making contact, about rivet size, be- tween the sheets of metal, passing a current through the contact, and applying pressure when the metal be- came plastic. A number of other kinds of welds, which, in a more or less degree, are modifications of the butt and spot welds, have found a very wide application. Lap or seam welding consists in passing a current through a lapped seam and applying pressure by means of rolls. Butt seam welding, as the name signifies, is a some- what similar process. Cross welding for making screens, etc., and tee and jump welding for fastening bars or pipes together, are other common welding pro- cesses. Welding Various Metals. — Although most of the metals may be welded successfully, the commercial ap- plication of resistance welding apparatus is usually limited to only a few of them. Iron and steel are most frequently subjected to welding operations, and are about the easiest to handle. The pressure imposed should be high and the metal should be kept below the melting point. Cast iron is very difficult to weld by the resistance process on account of its structure and composition. High carbon steel may be welded, provided it is afterwards annealed to remove the strains. Nickel steel makes a very strong weld. Gal- vanized iron of moderately thin gauge, may be welded. 210 ELECTRIC HEATING provided the joints are regalvanized when the opera- tion is completed. Sheet aluminum, brass, copper, iron and copper, and brass and copper, may also be suc- cessfully welded by skilled operators. Clamp for Thomson 4'0-A Butt Welder. Spot and butt welding operations are limited in the extent to which they can be applied commercially. If the metals are very thick, the amount of energy re- quired will be very large, and the radiation losses from the metals and the cooling water will become ex- cessive. ELECTRIC WELDING 211 Character of Resistance Welds. — If the weld is upset so that its cross sectional area is slightly greater than that of other portions of the piece, the joint should When finished have as much strength as the stock Winfield BB-255 Butt Welder. to the same diameter as the stock, it should have a strength efficiency of from 7^ per cent to 90 per cent. Ordinarily the strength of a weld may be improved by working. Care should be exercised to prevent heating the material too hot, or the weld may be burnt and thereby w^eakened. 212 ELECTRIC HEATING Butt and Spot Welding Costs. — The average costs of resistance welding are shown in the two following tables, which are figured on the basis of an energy rate of two cents per kilowatt-hour. Butt Welder Data. Rd. Iron Cost Diamter Kilowatts Time in Seconds per 1000 Welds in Inches. Required. to Make Weld. 2'. Cents per kw. % 2 3 0.04 Vz 5 5 0.14 % 12 15 1.00 1 18 20 2.00 IV2 50 40 11.10 2 75 50 20.84 Spot Welder Data, Cost per Gauges Thickness in Approximate Time in 1000 Welds of Sheet Fractions Kilowatts Seconds to at 2 Cents Steel. of an linch. Capacity. Make a Weld. per kw. 28 1-64 5 .3 0.009 24 1-40 7 .5 0.02 20 3-80 9 .7 0.035 16 1-16 12 .9 0.06 10 9-64 18 1.5 0.15 6 13-64 28 4.0 0.62 Energy Requirements and Character of Load. — Electric current is usually supplied to the machines at a pressure of 220 volts, which for ordinary welding operations, is reduced to from 3 to 5 volts. The power required for resistance welding opera- tions depends upon the kind of material, the area of cross section of the pieces, and the time taken for mak- ing the weld. The following table shows the average power and time required for butt welding: Power and Time for Butt Welding Iron and Steel. Area. Sq. In Power, kw. Seconds. Horsepower. 0.5 10.0 28 13.5 1.0 18.75 40 25 2.0 33.00 57 44.0 4.0 56.3 80 76.0 6.0 69.0 98 92.5 Power and Time for Butt Welding Brass. oa. Sq. In Power, kw. Seconds. Horsepower. 0.25 12 14 15.7 0.50 15 20 20.0 1.00 29.5 28 39.5 2.00 53 40 71,0 3.00 66 49 88.5 Power and Time for Butt Welding Copper. Area. Sq. In Power, kw. Seconds. Horsepower. 0.125 8.5 7 11.5 0.250 18 10 24.0 0.500 82 14 43.0 1.00 55.5 20 75.0 1.50 68 25 91.0 ELECTRIC WELDING 213 The character of resistance welding power loads depends largely upon the work that is being done. It is naturally very unsteady, and somewhat inductive. Unfinished Forgings of Meat Saw Back, S^/^-in. Ring and Two Single Throw Cranks Welded With Thomson Welder. CHAPTER XV ELECTRIC STEAM BOILERS. Application. — Where conditions are sucli that elec- tric energ-y may. be obtained at low cost during off peak periods or otherwise, or where only a small quan- tity of steam is required for certain operations, electric steam boilers may often 'be used advantageously. Industrial plants require steam for numerous purposes other than that of simply driving engines. Many machines, such as laundry apparatus and simi- lar devices, may use steam heat to better advantage than the usual form of electric heat. Where this con- dition obtains, steam boilers may be heated electrically to effect the desired results. Although electric steam boilers have not yet been applied very generally in the industrial field it is prob- able that the superior advantages which they afford will tend to bring them into wider use. Advantages. — The inherent features of electric steam boilers which commend them for industrial pur- poses are their efficiency of operation (often as high as 95 per cent), the reduction of labor cost, (no firemen needed), the safety of operation, (no danger of fire) and the convenience of location. As usual where elec- tric heat supplants fuel heat the annoyance di fuel burners, the heated atmosphere and the dirt are done away with. The boilers may be installed in any con- venient location and in places where other generators would be entirely impractical. Steam Boiler Calculations. — In order to make in- telligent recommendations for steam boiler installa- tions it is necessary to know something of the funda- mental principles of steam generation, the customary methods of rating the apparatus, and how to calculate the capacities required. The most important features to be considered together with some elementary defi- ELECTRIC STEAM BOILERS 215 nitions, tables, and practical examples are therefore set forth for the convenient reference of those less conversant with the subject. Boiler Efficiencies. — The definition of steam boiler efficiency is the ratio of the heat absorbed by the boiler in producing steam to the total amount of heat avail- able. As electric steam boilers are usually well lagged and equipped with immersion heaters it is apparent that practically all the energy applied is absorbed by G. E. S'team Boiler in Laundry of Estes Park (Colo.) Hotel. the boiler in producing steam. The efficiency of elec- tric boilers, therefore, may be as high as 95 per cent. The efficiency of a fuel-fired boiler, on the other hand, may vary anywhere from 50 per cent, or even less, to 80 per cent, depending upon the method of firing, the kind of combustible consumed, and the numerous losses of heat, the chief of which is that due to the temperature of the chimney gases. Boiler Horsepower. — The function of a boiler is that of producing steam by the evaporation of water and the term horsepower, having to do with the rating of boilers, should not be confused with the term horse- power relating to prime movers. Boiler horsepower is a measure of evaporation arid not of power. It is equal 216 ELECTRIC HEATING to an evaporation of 34.482 pounds of water per hour from and at 212° F. Since 970.4 B.t.u. (latent heat of evaporation) are required to evaporate a pound of water at atmospheric pressure after it has attained a temperature of 212° F., it is apparent that a boiler horsepower is equivalent to 34.482 X 970.4 or 33,461 B.t.u. Factors of Evaporation. — In order to calculate the amount of water that a boiler of a certain horsepower rating will evaporate per hour when supplied with water at a certain temperature and operated at a cer- tain pressure, it is necessary to divide by the corres- ponding factor of evaporation found in Table I. TABLE I. Factars of Evaporation. (Calculated from Marks and Davis TabL es.) Feed Temp. \awe Steam Prespure — Deg. F. 50 60 70 80 90 100 32 1.2143 1.2170 1.2194 1.2215 1.2233 1.2251 40 1.2060 1.2087 1.2111 1.2131 1.2150 1.2168 50 1.1957 1.1984 1.2008 1.2028 1.2047 1.2065 60 1.1854 1.1881 1.1905 1.1925 1.1944 1.1961 70 1.1751 1.1778 1.1802 1.1822 1.1841 1.1859 80 1.1548 1.1675 1.1699 1.1720 1.1738 1.1756 90 1.1545 1.1572 1.1596 1.1617 1.1636 1.1653 100 1.1443 1.1470 1.1493 1.1514 1.1533 1.1550 Assume a boiler of 5 h.p. rating supplied with feed water at 50° F. and operated at 60 pounds gauge pressure. The boiler will evaporate 5 X 34.482/1.1984 = - 143.9 pounds of water per hour. (The same boiler would, of course, evaporate 5 X 34.482=172.4 pounds of water per hour if supplied with feed water at 212° F. and operated at zero pounds pressure). Calculating Boiler Capacity. — It is necessary to kno'w three things in order to calculate the boiler rapacity required for any purpose with any degree of accuracy — (1) the boiler feed water temperature, (2) the steam pressure desired, and (3) the number of pounds of water that is to be evaporated per hour. The process is as follows : (1) Find the factor of evaporation from Table I corresponding to the temperature and pressure given. ELECTRIC STEAM BOILERS 217 (2) Multiply the pounds of water evaporated by the factor of evaporation and divide by 34.482. The result will be the required boiler capacity (neglect- ing losses in steam distribution). In case the number of pounds and character of fuel consumed under a boiler are known, the approx- imate boiler capacity utilized, or the equiv.alent ca- pacity required, may be determined as in the follow- ing example : Assume boiler consumes 40 pounds of 14,000 B.t.u. coal per hour with an assumed efficiency of 60 per cent. Then 40 X 14,000 X -60 = 336,000 B.t.u. input. Since one b.h.p. = 33,461 B.t.u., Then 336,000/33,461 = 10 boiler horsepower ca- pacity. Electrically Heated Boilers. — Since a boiler horse- power is equivalent to 33,461 B.t.u. per hour (the heat required to evaporate 34.482 pounds of water from and at 212° F.), and since one kilowatt-hour is equivalent G. E. steam Boiler Applied to Shoe-Stitching- Machine. to 3412 B.t.u. per hour, it is apparent that the capacity required to operate a standard boiler at 100 per cent efficiency is equal to 33,461/3,412 = 9.8 kilowatts per boiler horsepower. On the basis of 95 per cent effi- ciency (which is a fair average for electrically heated boilers) the capacity required would be 9.8/.95 = 10.3. 218 ELECTRIC HEATING Comparative costs of operating fuel and electric steam boilers under assumed efficiencies and using •fuel and electricity at various costs and rates are shown in Table II. TABLE II. Hourly Operating: Costs per B.H.P. in Cents. 60% Efficiency — Boiler Using- d5% Efficiency — Boiler Using 14,000 B.t.u. Coal. 3412 B.t.u. Electricity. Cost of Fuel per Ton. Cost of Current per kw-hr. $2.50 $5.00 $10.00 Ic 2c 3c .5c 1.0c 2.0c 10.3c 20.6c 30.9c Although the cost of steam produced with fuel is much less than that produced electrically according to Table II, the labor cost and the many disadvantages of fuel must also be taken into accounts in making intelligent comparisons. Electrical Energy Required to Evaporate Water. — In order to determine the amount of energy required to evaporate a certain weight of water per hour sup- plied at certain temperatures and operated under cer- tain pressures Table III will be found useful. TABLE III. Watts Capacity Requiretl to Evaporate one Pound of "Water per Hour Into Steam Assuming^ Certain Initial Feedwater Temperatures and Certain Final Pressures. (Transformation 100% Efficiency.) Lb. Gauge -Initial Feed Water Temperatures De^ees Fahr. Pressure. 40 50 60 70 80 90 100 110 334.8 331.9 328.9 326.0 323.1 320.2 317.2 314.3 10 337.7 334.7 331.8 328.9 326.0 Si'?3.0 320.0 317.2 20 339.6 336.6 333.7 330.8 327.9 324.9 322.0 319.1 30 341.0 338.1 335.1 332.2 329.3 326.3 323.4 320.5 40 342.1 339.2 336.2 333.3 330.4 327.5 324.5 321.6 50 343.0 340.1 337.2 334.2 331.3 328.4 325.4 322.5 60 343.8 340.9 337.9 335.0 332.1 329.2 326.2 323.3 70 344.5 341.5 338.6 335.7 332.7 329.8 326.9 324.0 80 345.0 342.1 339.2 336.3 333.3 330.4 327.5 324.5 90 345.6 342.6 339.7 336.8 333.9 330.9 328.0 325.1 100 346.0 343.1 340.2 337.3 334.3 331.4 328.5 325.5 Assume 100 pounds of water at 60 degrees F. feedwater temperature is to be evaporated under 70 pounds pressure and at an efficiency of 95 per cent. The capacity required would be : 100 (pounds) X 338.6 (from table III)/.95 (efficiency) = 35,642 watts or 35.642 kw. Furthermore, since one boiler horsepower is equivalent to 10.3 kw. at 95 per cent efficiency, the ELECTRIC STEAM BOILERS 219 size boiler required for the operation would be : 35.642/10.3 = 3.46 boiler horsepower. These figures may be checked by the method sug- gested under paragraph headed "Calculating Boiler Capacities." Steam Boiler Apparatus. — The Simplex and Gen- eral Electric companies manufacture electric steam boilers in various capacities. They are usually equipped with water and steam gauges, safety valves, and other standard boiler fittings. Simplex boilers G. E. Electric Steam Boiler. are of the horizontal type and are somewhat similar to so-called ''fire tube toilers" in that the heating ele- ments are inserted in longitudinal tubes passing through the shell. These tubes are welded in the boilers and the heating elements may be readily re- moved for inspection and repairs. The General Electric boilers are of the vertical type and are usually heated by means of direct immer- sion heaters which are inserted into the shell radially and from the outside. They are mounted in rows around the circumference and near the bottom of the tank. The capacity of each unit is one kilowatt and obviously a large number are employed for heating the larger boilers. The sizes and capacities of General Electric steam boilers are set forth in Table IV. 220 ELECTRIC HEATING TABLE IV. General Electric Steam Bollerai. Lbs. Evap. Approx. per hr. Boiler Gallons Height Floor Kw. Ca- From and Horse- Capacity, Over all Space No. pacity. at 212° F. power. Full. In Ins. In Feet. 10 30 101 2.9 85 59 3 x4 11 45 151 4.4 110 66 3 x4 12 60 201 5.8 145 74 3^x41/^ 13 85 285 8.3 180 79 3%x4i^ 14 100 335 9.7 250 85 4 x5 15 150 503 14.6 340 92 4^x51/2 16 200 671 19.5 480 104 5 x6 To determine the amount of water which the different sized boilers will evaporate under various pressures and with various feedwater temperatures, divide the figures in column 3 by the corresponding factors of evaporation found in Table I. The boilers are all thoroughly lagged with heat- insulating material. Although it might be considered unsafe to operate the present open shell and fire tube types of electric boilers at excessively high pressures, there seems to be no obvious reason why electric steam boilers might not be designed on principles simi- lar to those of water tube boilers and operated at any desired pressures. CHAPTER XVI GENERAL APPLICATIONS OF ELECTRIC HEAT. Diversity of Use. — Although it is impossible to enumerate in a single chapter the many uses to which electric heat has been successfully applied, a number of its possible applications in the industrial field are set forth. The descriptions are arranged in alpha- betical order for convenient reference. Automobile Heater. — A number of small low watt- age heaters have been developed for placing in auto- mobile hoods to keep the engtines and radiators warm in cold weather. These heaters keep the water from freezing and make the engines start more easily. Bacteriological Incubators. — Electric heat is par- ticularly well adapted for bacteriological work. The character of the heat afforded, the positive automatic temperature control apparatus available, and the ab- sence of fire hazard make electrically heated devices of this nature verv desirable. A number of bacterio- 222 ELECTRIC HEATING logical ovens are in actual successful use and the de- sired temperatures are maintained to within a frac- tion of a degree. Bath Cabinets. — Every advantage of the Turk- ish or steam bath room is afforded by the electric cab- inet bath, and it is being substituted for them quite generally. The expense of maintaining hot air and steam rooms and the disagreeable features attending their use are thereby eliminated and the patients given better and more healthful treatments. The cabinets are usually constructed of wood, steel, or marble and are designed for patient's use Electric lialh Cabinet. in either a sitting or reclining posture. The in- teriors are lined with reflecting surfaces. Rows of electric lights (usually carbon filament) are mounted close to these reflecting surfaces and the patient re- ceives the beneficial effect of the actinic light rays as well as of the heat produced by the lights surrounding him. The wood and steel cabinets are generally lined with mirrors, whereas marble acts as the reflecting surface where it is used. The patient's head is always allowed to protrude from the cabinet and he is never forced to breathe the hot air contaminated by the toxic GENERAL APPLICATIONS 223 emanations of his person, which is unavoidable in the hot air and steam rooms. The marble cabinet shown in the illustration is made l)y James B. Clow & Sons. It is lined with 56 sixty-watt car'bon lights and has a total capacity of 3360 watts when all the six control switches are closed. The range of temperature is from 80 deg. to 180 deg. F. From 3 to 10 minutes is required to bring out a sweat and the average duration of the bath is from 12 to 20 minutes, depending upon the initial heating, the outside temperature, and the physical condition of the patient. Beer Vat Dryer. — For drying out vats in a brew- ery during the varnishing season, the General Electric beer vat dryer is convenient and satisfactory. It is 4 feet long, 8^ inches wide, 4 inches high and is fitted G. E. Beer Vat Dryer. with six 500-watt resistance tubes mounted on center and end castings. The ends and sides are of sheet metal, and the top and bottom of galvanized wire mesh. It is claimed by the manufacturers that one of these devices will dry out a 50-barrel vat in about 10 hours. Two heaters are recommended for a 150- barrel vat, and three for a 350-barrel vat. Branding Irons. — A large number of special elec- trically heated branding irons are in use. They are ideal for branding wood, leather, meats, etc. Button Die Heater. — Electrically heated dies have been used for some time in the manufacture of cellu- C. H. Heater Applied to CeUuloid Button Die. 224 ELECTRIC HEATING loid buttons. These devices are made in capacities of from 60 to 150 watts, and are usually controlled by rheostats mounted on the bed plates. A number of dies may be mounted on one head. Can Capping Machine Heater. — An application of electric soldering iron units of 250 watt capacity to can capping machines has been designed by the General Electric Company. Apparatus operated in this manner has been found much more satisfactory than gas heated equipment. Candy Batch Warmer. — The electric batch warmer is portable and has a swing adjustment so that the heat can be thrown in different directions as de- sired. It serves the same purpose as the open gas C. H. Batch Warmer. warmer, but has certain obvious advantages over fuel apparatus. The Cutler-Hammer batch warmer is made in two standard sizes, as follows : Length in Inches, Watts. No. Heats. 24 2500 3 48 5000 6 Celluloid Embossers. — A method of attaching 25 watt and 38 watt soldering iron units to the embossing heads on the lower part of celluloid embossing presses has been developed by the General Electric Company. The electrically heated dies are ideal ; a maximum tem- perature of 140° F. is maintained ; and all danger from working with inflammable material is obviated. GENERAL APPLICATIONS 22f Chocolate Warmers. — For maintaining chocolate at proper temperature for dipping, the electrically heated warmers have proved their superiority on ac- count of the accuracy of adjustment possible and the cleanliness and convenience afforded. They consist of two pans ; an inner one holding the chocolate and an outer one fitted with a surface heating element. Chocolate warmers in the following sizes and ca- pacities may be obtained for flush mounting on dipping tables : C. H. Chocolate Dipping- Table With Warmer and Side Pans. Rectangular Chocolate Warmers (Cutler-Hammer). Quarts Capacity, Inside Dimensions in Ins. —Watts- 2/3 Full. Length. Width. Depth. High. Medium. Low 4 12 3/16 6 3/16 5 180 90 45 6 14 1/16 7 5/16 5% 220 110 5& 10 141/2 10 7 310 155 77 12 20 12 51/2 375 188 94 Rectangrular Tjpe (Westi nghouse). 4 12 61/2 5 220 110 55 Round Type Chocolate Warmer (Cutler-Hammer). Quarts. Capacity. Inside Dimensions, Ins. — Watts — 2/3 Full. Diameter. Depth. High. Medium. Low. 4 9 6% 160 80 40 ELECTRIC HEATING Electrically heated side pans are furnished with the Cutler-Hammer rectangular chocolate warmers in- stead of marble slabs. Two of them may be mounted on opposite sides of the warmer. They are made in the following standard sizes HEATER RECEPTACLE CONTROL SWITCH CHOCOLATE PAN Westinghouse Chocolate Warmer. Heated Side Pans. Dimensions in Inches. Watts. 12"xl5" 25 12"xl7" 29 12" X 221/2" 38 Clothes Dryers. — Where fuel cost is high or where operating cost is relatively unimportant in com- parison with convenience, electrically heated clothes dryers are desirable. It is obvious that the drying of clothes in the laundry saves time and eliminates the many disadvantages of hanging out the washing on the old-fashioned clothes line. The Chicago electric dryer is made of heavy gauge galvanized sheet metal with single casing, double cas- ing insulated with asbestos, or double casing insulated with an intervening air space. The panels of the racks are of similar material. The rear panels are provided with extension plates, so that when the racks are pulled out, the heat will not escape from the machine. The brackets are of cast iron, and the hanging bars are of galvanized pipe. The sheave wheels are run on ball bearings. The base of the cabinet below the racks is provided with galvanized wire screen for the protection of clothes that might fall from the racks. The electrically heated dryers are made in four standard sizes for use on 110 or 220 volt circuits. Lineal Ft. Dryer Outside Dimensions. No. Hanging Kw. Ca- Number. Height. Length. Width. Racks. Capacity pacity. E 29 7' 7' 2' 1" 2 78 3 E39 7' 7' 2' 10" 3 117 4.5 E49 7' 7' 3' 7" 4 156 6 E59 7' 7' 4' 4" 5 195 7.5 GENERAL APPLICATIONS 227 Corn Popping Machines. — An electric corn pop- per of 1500 watts heater capacity and operated with a one-sixth horsepower motor is now available. It is similar to those seen in public places, and has a ca- pacity of about 60 bags of popcorn per hour. Corset Irons. — The Simplex corset iron is made in an 8^ pound, 500 watt size. It may be obtained with either a hand or an automatic regulator or a com- bination of both. Drying Ovens. — Specially constructed ovens are used for drying lumber, for removing moisture in photogravure work, for drying leather boxes and traveling bag parts that have been glued, and for re- moving the moisture from bottles and cans before filling with powders. Embossing Press Heaters. — Any gas or steam heated embossing head may be easily fitted with electric heaters and higher operating efficiencies insured. They may be heated quickly (usually from ten to fifteen minutes), and afiford a sensitive and uniform temper- ature over the entire surface. Simplex embossing press heaters have been made in a great variety of sizes and capacities. They are usually made to order on account of the great variety of press heads in use. The heaters are fiat discs about one inch thick. They are bolted to the press head and the embossing dies placed over them. They may be made in two or more sections, so that portions only of the head may be heated, if desired. Cutler-Hammer press heads and press blocks are also manufactured in a variety of sizes and capacities for industrial use. The following information is usually required for making up a design of press heater: (1) Nature of work to be done. (2) Speed of operation. (3) Temperature required. (4) Pressure to be applied. (5) Dimensions of dies and manner applied. (6) Sketch showing dimensions of press head. 228 ELECTRIC HEATING Sheridan No. 8D Press Equipped With 46 in. x 33 in. Press Head. Engraver's Stoves. — Three-heat stoves of 600 watts capacity are being- used successfully for heating engraved plates during the inking process. Envelope Gum Dryer. — With a 500 watt heating unit fitted in the blower cabinet, the capacity of a machine will be increased about 100 per cent. Fan Drying Equipment. — A small dryer of 1000 watts capacity, which is attachable to a standard fan motor, has been developed by the General Electric Company. It has a wide field for application in pho- GENERAL APPLICATIONS 229 C. H. Engraver's Stove. tographic studios for drying prints and negatives. The heating coils are mounted vertically in an aluminum frame and covered with a screen guard. Motion Picture Film Dryer. I Film Dryers. — A large motion picture studio has developed a film drying oven, consisting of an outside casing, within which a large ribbed cylindrical reel, 230 ELECTRIC HEATING similar to a ferryboat paddle wheel, is mounted. The oven is heated with four 3000 watt G. E. beer vat dryers mounted around the sides. The film is wound on the outside of the reel. The drying process com- pletes work in 30 minutes that formerly required 10 hours' time, and much better results are obtained. E. & A. Type FW Laboratory Flask Heater. Flask Heaters. — A flask heater for laboratory use is very convenient. It is made of copper with a con- centric ring top. The small size is 8^x4 inches deep, and consumes 500 watts at maximum heat. Gilding Wheel Heaters. — These devices are used for bookbinding, and are convenient on account of the absence of soot and dust and the concentrated heat afforded. They are fitted with heaters which revolve on roller bearings. Ordinary dies may be used with these heaters by turning a recess on one side and drill- ing holes for the clamping studs. Simplex gilding wheel heaters are made in the following sizes and ca- pacities : 77 watt heater, 3 19/32" diameter, 21" long. 85 watt heater, 4" diameter, 21" long-. A rheostat may be supplied with the larger size for finer temperature adjustment. Glove Stretchers and Laying-off Boards. — The electrically heated glove stretchers and laying-off boards manufactured by the C. L. McBride Manufac- turing Company are ideal for the dry cleaner and glove manufacturer. The stretchers are superior to the or- dinary steam heated devices. Steam laying-off boards are not flexible ; will not give to allow the gloves to be GENERAL APPLICATIONS 231 fitted, and consequently require more time to adjust the glove fingers. The heat also varies with the pres- sure, and the quality of the work is not uniform. These disadvantages are overcome in the electric glove stretcher. The temperature is regulated by a thermo- stat. It is mounted on a revolving base. The quality of the work is better, and may be done more rapidly and with less skilled labor than where steam is used. Only a relatively few forms are required, because each stretcher will make four full sizes of gloves from one form. The electrically heated laying-oi¥ boards are made for finishing dry cleaned gloves, and may be used in a kid glove factory although they are too light for heavy gloves. They are much cleaner and safer and will turn out more and better work than steam boards. Glue Pots. — Electrically heated glue pots elimi- nate soot, smoke, and flame; do away with steam and gas pipes; are readily moved from place to place, and insure even temperature regulation. They are manu- factured both with and without water jackets. The relative sizes and capacities of glue pots made by three prominent manufacturers are as follows : Westinghous" Cast Iron Glue Pot. Simplex No. 40S Glue Pot. General Electric Glue Pot. Pot Make. Capacity. Gen. Electric. ..1/^ pt. to 8 qt, Gen. Electric... 1 pt. to 4 qt. Westinghouse.. 1 pt. to 4 qt. Simplex 1 pt. to 2 qt. Simplex 1 pt. to 20 qt. American 2 pt. to 4 qt. Small. Large. Low. High. Low. High. 20 250 jacketless 85 340 275 1100 jacketed 55 200 200 660 jacketed 110 440 220 880 jacketless 85 330 625 2500 jacketed 125 500 250 1000 jacketed 1-heat 3 -heat 3-heat 3-heat 3-heat 3-heat 232 ELECTRIC HEATING Glue Cookers. — Quantities of glue may be heated in large pots and transferred to small pots for use in various parts of an establishment. The cookers are usually heavily insulated against heat losses. 1 • ■■• ■ 1 ! i T " ] ^ ^ , "T"'" ! !> i 1/-— — \J Section of a Westinghouse Glue Cooker. Tabular specifications of standard Westinghouse glue cookers are as follows : Gallons V^atts Input. No. of Capacity. Starting. Running-. Heats. 3 1800 450 2 5 2200 550 2 10 2700 675 2 15 6000 750 5 20 6600 825 5 25 7200 900 5 The following data refer to standard General Electric glue cookers : Gallons V7atts Input. Av. Hr. Time Floor Space Capacity. Starting. Running. to attain 165° F. in feet. 20 10,500 450 1 3i4x3y4 35 14,000 5i00 ly* 31/2x8^ 50 16,500 600 1^ 3%x3% 80 20,000 700 1% 4 x4 140 26,500 850 2 4y2x4% 220 32,aoo 1,050 2y2 5 x5 Gold Leaf Stamp Heaters. — These devices may be used in place of gas for stamping gold leaf on combs, pipes, neckwear, etc. A Simplex die heater consuming 80 watts has been designed to fit a standard pencil stamping machine for imprinting gold leaf letters. GENERAL APPLICATIONS 233 Hatters' Flanging Bags. — Electrically heated flanging bags are superior in every way to bags heated over steam bake ovens. The heat is constantly gen- erated within the bag; the thermal efficiency is greater ; the temperature is more uniform ; and no time is lost C. 11. I'langing- Uag'. in reheating. Hats may be flanged in less time and with better and more uniform results. The Cutler- Hammer flanging bags consume 440 watts, and are furnished with a metal pan fitted with lifting ears. The sand, lifting tackle and canton flannel covering are provided by the user. Hatters' Hand Flats. — Four faces of the straw hat- ters' hand flats are working surfaces. Three standard styles are made by the Cutler-Hammer Company. The hand flat is mounted on a support, and may be used in any desired position. Cleanliness is essential in the manufacture of straw hats, and the clean, uniform heat supplied by the electric hand flat makes for in- creased speed and perfection of product. The energy required for these devices varies from 550 to 700 watts, depending upon the style of hand flat used. Hatters' Hand Shell. — The Cutler-Hammer hat- ters' hand shells conform in shape to the old-fashioned shells. The body of the shell is a single casting, and can be dipped in water for cooling the faces of the iron. These irons are made in the following standard weights and capacities : 234 ELECTRIC HEATING Weight in Pounds. 10 1^ 12 15 Watts. 300 or 350 300 or 350 350 or 500 350 or 500 Simplex hatters' irons are made in 9 and 15 pound sizes, and with 450 watts capacity each. They may be provided with plain or automatic regulators. C. H. Hand Shell, Hand Flat and Velouring- Stove. Hatters' Velouring Stove. — The Cutler-Hammer velouring stove is encased in a heavy cast iron frame with tight joints to prevent particles of felt from lodg- ing in the crevices. They are made in the following standard sizes for either single or two-heats : Size of Top, Watts Capacity in Inches. Single-Heat. Two-Heat. 4y2x6 315 315-475 514x7 450 450-675 Doran Machine Iron Nos. 1 and 2. Hatters' Machine Irons. — Irons for use on hatters' machines are more satisfactory, more economical, and result in better work and greater output than other such appliances. Gas heated machine irons, equipped GENERAL APPLICATIONS 235 with gas and air-blast tubes, soon develop loose con- nections, create dangerous hot spots, and do not main- tain a uniform heat. Tweedy Right Hand CurHng Machine Iron. Cutler-Hammer irons are made for the following hat blocking and curling machines : Watts. Doran Machine Iron No. 1 300 Doran Machine Iron No. 2 30i0 Doran Machine Iron No. 3 275 Newark Machine Iron 400 Tweedy Right Hand Curling Iron 750 Tweedy Left Hand Curling Iron 750 Hot Air Blower. — A 25 kilowatt General Electric hot air blower fitted with 152 ribbon wound flat heat- ing units and a blower fan has been found useful for drying transformers and other similar operations. The volume and temperature of the air supplied naturally depends upon the size and speed of the fan. Industrial Heating Units. — In order to avoid de- signing and manufacturing special heating units for each industrial application that is presented, the General Electric Company has standardized on three types of units, one or more of which are adaptable to the usual conditions that are met. These units are known as cartridge, flat leaf, and tubular type units. Cartridge units are made in various capacities up to 750 watts, and in sizes up to 1^ inch diameter and 8 inch length. These units operate at a dull red heat. They are usually fitted -into drilled holes in castings and bolted to the body to be heated. They consist of 236 ELECTRIC HEATING Westing-house Narrow Type Industrial Heater. Westing-house Wide Type Industrial Heater. resistance ribbons wound edgewise, cemented and sealed inside of metallic tubing. Flat leaf units are used for heating flat surfaces. They are made in capacities of 300 watts or less and with dimensions of 6 inches by 2 inches by }i inch. They consist of resistance ribbons wound on mica sheets and clamped between iron protecting plates. Any desired number of these units may be bolted to the surface of any smooth, flat surface to be heated. Tubular type units are used for air heating and are made for low temperature work. The standard N/r No I Htr No Z Heater Terminals I To 7. J-Heat Heaters Htr No I Htr No 2 Htr No 3 Htr No 4 neater \ Terminols\ I -Heat Heaters To Line To Line 3-HeatSnapSii/itch Higt) tl J r To Heaters Two-Heat f(nife Switch. Diagram for Connecting Two Single Heat Heaters or Multiples Thereof for Three Heat Control. GENERAL APPLICATIONS 237 size is 2 in. in diameter and 22 in. long, and dissipates about 350 watts. It consists of resistance wire wound on an asbestos tube and coated with a stiffening of insulating compound. The Westinghouse Company has recently devel- oped a very complete line of ''steelclad" heating units for industrial purposes. They consist of flat ribbon resistors assembled on mica sheets covered with steel casings, and provided with suitable terminals. They are made in the form of bayonets with single or three heat control, in lengths varying from 10 in. to 50 in. The narrow type is j/g in. thick and 1% in. wide, and the wide type 3/16 in. thick and 2%. in. wide. The wattage of these units may be calculated from the fol- lowing table : Maximum Watts per Inch of Length. Class. Wide Type. Narrow Type. A (Ovens and drying- rooms) 15 7.5 B (Ordinary Air Heating) 30 15 C (Pressheads, hot plates, etc 50 25 Ironing Machines. — Laundry machines of all kinds may be equipped with electric heaters. They insure a clean, sanitary, cool laundry, and result in producing more and better work. An example of an application of electric heat in the laundry is that of the American Iron Machine Company's ''Simplex Ironer," which is made in the following sizes and capacities : Simplex Ironers. Length of roll in inches. 24 26 32 37 42 46 48 56 Diam. of roll in inches.. 6 7 7 7 7 7 8.5 8.5 Ironing shoe face in inches 58888899 Ironing shoe contact, ins. . 2.5 5 5 5 5 5 6 6 Ironing speed ft. per min. 6.5 7 7 7 7 7 8.5 8.5 Kw. capacity — high 1.85 2 2.5 3 4 4.8 5 6 Kw. capacity— medium. . . 1.25 1.3 1.7 2 2.7 3.2 3.4 4 Kw. capacity— low 60 .75 .85 1 1.3 1.6 1.7 2 Size of motor in hp 1-10 1-8 1-8 1-8 1-6 1-6 1-4 1-4 Laboratory Hot Plates. — The uniform, depend- able and safe heat obtainable from electric hot plates and stoves make them most desirable. Simplex 4i^ in. by 24 in. Laboratory Hot Plate, 238 ELECTRIC HEATING Rectangular Simplex hot plates of the following dimensions and capacities are available for securing various temperatures : 6" X 6" 500 watt three-heat 6"xl2" 750 watt three-heat 2%"x 24" 500 watt three-heat 41/2" X 24" 600 watt three-heat 3"x6" 200 watt three-heat 6"x6" 350 watt three-heat Small, round Simplex discs in sets of six mounted on slate bases are convenient for milk testing and other laboratory operations. 6- 31/^" discs total &00 watts single-heat. 6- 4%" discs total 1500 watts single or three-heat. Laundry and Tailors' Irons. — The conditions un- der which these irons are used are vastly different than those in the home. They are usually subject to rough. Simplex No. 1540 Drag Iron. careless handling, and severe long hour use. They must be heavily and durably constructed to meet ordi- nary requirements. A large variety of irons are available for industrial use. Pointed and round nose, smoothing and finishing- irons are manufactured in many sizes. Those made for laundry work usually vary in weight from four to twelve pounds and consume from 275 to 750 watts. Drag irons are made in weights of from 30 to 50 pounds and wattages of from 1400 to 1600 watts. Puff irons in egg and half egg shapes are made in capacities of from 150 to 400 watts. Tailors' irons usually vary from 12 to 25 pounds in weight and from 600 to 900 watts in capacity. They are made with diamond, oval, and special broad noses. Simplex irons of various sizes and shapes are made for use in pressing machines. GENERAL APPLICATIONS 239 Westinghouse, American, Cutler-Hammer, Gen- eral Electric and Simplex laundry and tailors' irons are manufactured in a variety of types, shapes and sizes. C. IL Tailor's Jr.. Leather Creasing Tool. — A recently developed de- vice for branding designs, ruling parallel lines, and edge finishing leather articles has been found very use- ful. The tool is designed on the principle of a solder- ing iron and differs only in the tip and handle. Linotype and Monotype Pots. — Among the numerous advantages gained by the application of electric heat to type metal pots are rapid heating, per- fect temperature regulation, absence of gas fumes, smoke and soot, elimination of excessive room tem- perature, ideal working conditions, no burning out of the tin of the metal mixture, and production of solid, sharp slugs. The Cutler-Hammer pots are equipped with im- mersion heaters, heavy thermal insulation, and auto- matic temperature control. The latter consists of a dynamic thermometer and a magnetic switch panel. Expansion or contraction of mercury in the thermom- eter actuates a relay which in turn operates the mag- netic switch, cutting the current in the heating ele- ments on or ofif. It maintains a temperature of approximately 550° F. in the type metal. Initial heating requires 240 KLECTRIC HEATING C. H. Linotype Pot. 1600 watts, for about 50 minutes after which 550 watts is sufficient to maintain the temperature when 100 slugs are being cast per hour. G. E. Monotype Pot. The General Electric pots are usually equipped with standard cartridge units. Regulation of the hear is obtained by means of a hand operated rheostat. For heating a linotype pot holding 40 pounds of metal a GENERAL APPLICATIONS 241 maximum capacity of 2250 watts is provided. To maintain working temperature using 8 pounds of metai per hour 750 watts is required. P'or heating the same weight of metal in a monotype pot 2900 watts is pro- vided, and for maintaining the proper temperature, using 16 pounds of metal per hour, 2400 watts is re- quired. Liquid Heating Tanks. — Manufacturing processes that require the use of hot liquids for dipping purposes may often utilize electrically heated tanks to advan- tage, especially where the solution is of an inflam- mable or explosive nature. The vessels are usually well lagged and fitted with covers. Tanks of the following dimensions and capacities are made for heating liquids by the General Electric Com pan v: Average Hours Capacity Required in Total Outside Dimensions. for Heating Gallons. Kilowatts. Diameter. Height. Oils to 212° F. 40 16.5 27" 25" 1.3 60 22.5 31" 29" 1.4 85 30 35" 31" 1.5 125 39 39" 35" 1.7 200 52.5 46" 40" 2 300 58.5 54" 45" 2.7 500 67.5 62" 55.5" 3.9 750 75 70" 62.5" 5.3 1000 79.5 76" 68.5" 6.7 I r Matrix Dryers. — The most important factors to be considered in matrix drying are quality of the mat, cost of drying and speed of drying. The temperature usually required for this work is from 350° to 400° F. The common methods of drying are accomplished by the use of either gas or steam heat. In addition to the many obvious disadvantages of gas heated ap- paratus, it does not provide the uniform temperature that is so desirable for this class of work. Steam heated dryers, on the other hand, supply a uniform heat, but unless excessively high pressures are avail- able the operating temperatures are too low for quick work. Electrically heated matrix dryers have overcome all the undesirable features of other apparatus. The heat is clean, safe, dependable, and automatically regu- lated to provide the desired operating temperatures, 242 ELECTRIC HEATING f C. H. Matrix Machine Heater. and it does away with the maintenance of troublesome and costly equipment. Cutler-Hammer matrix dryers are manufactured complete, ready to slip into the bed of the machine. G. E. Matrix Drying Press. The temperature is regulated by the pressure of satu- rated steam generated in a tube cast into the heater and attached to a contactor pressure gauge, which in GENERAL APPLICATIONS 243 turn actuates a magnetic switch, cutting the current on and off. The dryer is also fitted with pilot lamps to indicate when energy is being consumed. General Electric matrix dryers are also automat- ically controlled. The standard size is rated at 28 kilowatts, and is applied intermittently by the auto- matic regulator. It is claimed by the manufacturers that these dryers will consume about one kilowatt per hour per mat. Meat Brander. — This device is used for inspection stamps and is legible at end of curing process. A ham branding die made by the General Electric Company consists of a 21 pound block of cast iron heated with two 600 watt cartridge units. The branding die is of cast brass inserted in the top of the body casting. After initial heating, low heat is maintained. Each ham is branded by placing it on top of the heated die for from 3 to 4 seconds. Metal Melting Tanks. — For bringing tin, lead, solder, babbitt metal and various alloys to the melting point, electrically heated tanks can often be used to advantage, especially where it is desirable to secure accurate temperature adjustment. These tanks should be heavily constructed and provided with efficient thermal insulation. Tanks of the following sizes and capacities are manufactured by the General Electric Company : Capacity 80% Full. Lbs. .Lbs. Inside of Tank (inch es). Watts Lead. Tin. Diam. Length. Width. Depth. Capacity 30 19 4%" 5y2" 2,100 50 30 5%" evz" 2,400 75 45 eva" 6%" 3,000 10(0 60 7" TVs" 3,900 2>00 125 9" 9V2" 4.550 300 190 10" 11%" 6,500 400 250 11" 12%" 8,450 560 360 15" 13" 9" 13,000 80(0 520 15" 13" 13" 15,600 1080 690 20" 13" 13" 17,500 1230 860 20" 16" 13" 22,1(00 1640 1050 20" 16" 16" 22,800 2060 1275 25" 16" 16" 26,000 2330 1600 30" 16" 16" 28,600 2960 1900 30" 19" 16" 30,0(00 It is claimed that a 3000 watt pot will melt approx- imately 52 pounds of alloy consisting of 18 parts anti- 244 ELECTRIC HEATING mony, 20 parts tin, and 100 parts lead in one hour. Medium heat will perform the same operation in 3 hours. Cutler-Hammer type metal crucibles arc made with external or immersion heaters in sizes of from .SO pounds to 500 pounds capacity. G. E. Metal Melting Tank. Number Brander. — This recently developed de- vice consists of an electrically heated circular plate, on the outside of which is mounted a small wheel bear- in ^^ in. figures reading from to 9. G. E. Oil Tempering- Bath Oil Tempering Baths. — Where a large amount of tool tempering is done the electric oil bath is indis- pensable. Uniform temperature control is attained, and fire hazard, uncertainty, and harmful oxidation of the metals is eliminated in this process. The work may be done successfully with unskilled labor because the temper is drawn by the submersion process. GENERAL APPLICATIONS 245 General Electric oil tempering baths furnished with or without cooling coils and controlling panels are made in the following standard sizes and capacities : Oil Capacity Dimensions in Inches. Maximum Gallons. Length. Width. Depth. Kilowatts. 9 22 12 8 6 11 18 12 12 7.2 37 30 16 18 20 The drawing temperature of different grades of steel varies from 300° to 320° F. The 20 kilowatt size bath is said to have drawn the temper of 363 pounds of steel ball bearings in 1 hour and 45 minutes with a total energy consumption of 9.5 kilowatt hours. These baths are being used successfully for melt- ing rosin compounds required in the manufacture of shrapnel shells. They may be used equally as well for heating and melting many other compounds. C. H. Pallette Heater. Pallette Die Heaters. — In book binding establish- ments these devices have a number of advantages be- cause of the concentrated heat, freedom from dust and soot, and better working conditions brought about. The Simplex standard machine die heater is of 140 watts capacity, and fitted with rheostat and flexible cord. It is provided with a triangular piece of metal 246 ELECTRIC HEATING across the back for fastening in the head of the ma- chine. The rectangular pocket for the dies is 1>4 in. X 2^ in. X 5/^ in. deep. The hand die heater is of 135 watts capacity. The groove for the die is ^ in. x 5 in. X i^ in. deep. The length of the device including the handle is 9^2 in. Paper Seal Moistener. — Electric heat has been found convenient for heating water in the small paper seal moisteners used in sealing packages and cartons. Paper Seal Moistener. A small 30 watt heating unit immersed in a container 4 in. X 6 in. x 2 in. deep, will raise the temperature a sufficient amount. Paper Warmer. — In order to do away with the sticking effect produced by static electricity General Electric tubular heaters have been placed under the paper of large printing presses and satisfactory re- sults obtained. Peanut Roasters. — Wm. B. Berry & Company has developed a line of electrically heated and operated peanut roasters. They are built in standard sizes of 16, 24, and 32 quart capacities, and in a number of designs. The latter is equipped with 1.2 kw. in heating units and will roast about one bushel of peanuts per hour. The manufacturers claim the machines have been used successfully for roasting coffee as well as peanuts. Perforator for Drawings. — A recently developed heating device which makes minute perforations may be run over a drawing and the pattern used for a stencil. GENERAL APPLICATIONS 247 Photographic Drying Oven. — An unlagged galvan- ized iron oven 5 ft. long, 30 in. wide, and 30 in. high, fitted with two 500 watt General Electric tubular type heaters mounted 2 in. from the floor is said to dry pho- tographic prints in from 30 to 45 minutes, whereas from 3 to 4 hours was formerly required for drying them on blotting paper in the open air. Ventilation is provided by a 6 in. hole in the bottom and a small damper in the top. The prints are placed on blotting paper on three wire mesh shelves. Another installation, consisting of a revolving gal- vanized sheet iron drum 3 ft. in diameter and 2 ft. wide, heated by means of a 2000 watt three-heat Amer- ican radiator inside the drum, and operated by means of a l/6th horsepower motor, gave very quick results. A cloth belt passing around the drum and over rollers mounted on the framework permitted the wet prints to be inserted between the surface of the drum and the cloth belt. The warm surface of the drum and the dry cloth rapidly remove the moisture. Pipe Thawing Outfits. — Portable outfits have proven serviceable for thawing frozen pipes. The high tension leads are connected to the main line feeders and the low tension leads are attached to opposite ends of the frozen pipe section. In residences one lead is usually attached to the faucet and the other to a street hydrant. Connections may be made to two hydrants when street mains are frozen, or excavations may be made for attaching leads direct to the pipes. Pitch Kettles. — Portable devices for heating pitch, varnishes, oils, etc., have a wide range of application They are usually provided with three-heat control switches. The maximum heat is used for heating up the substance, medium heat for stirring, and low heat for maintaining a constant temperature. Simplex pitch kettles have the following dimen- sions and capacities : 12" X 21/^" deep 4 quart 1300 watts maximum. 15" X 2y2" deep 7 quart 1600 .watts maximum. 19" X 9 " deep 40 quart 3000 watts maximum. 30"xl4%" deep 120 quart 7000 watts maximum. 248 ELECTRIC HEATING Pleating Machine Heaters. — An installation for pleating dress goods, made by the General Electric Company, consisted of a 600 watt heating unit fas- tened to the frame so as to project inside one of two 7-inch by 3-inch corrugated rollers, and a temperature of about 450° F. was attained. The electric heater was substituted for a gas burner, which was more or less dirty, dangerous, and uncomfortable to work over. Pouring Pots. — Where it is desired to keep wax and pitch compounds at the proper consistency for pouring, General Electric portable pots, made in forms similar to its jacketless glue pots, are useful. Printing Ink Heater. — In order to keep printing ink warm and fluid in cold weather, a small heating unit placed beneath the ink pad has produced good results. Rectifier Tube Boiler. — For lengthening the life of rectifier tubes the General Electric Company has developed a means of boiling the tubes in water for removing the carbon deposits on the inside of the glass. A copper tank 29^ in. long, 16^ in deep, and 13 in. wide, lagged with asbestos paper, fitted with a tight cover and heated with nine 1175 watt cartridge units constitutes the equipment. Roofing Material Vulcanizer. — This application of electric heat as a substitute for gas heat reduces the unit time of joining rolls of rubber roofing paper con- siderably. The heating units consist of mica insulated resistance ribbon clamped between iron plates (2 in. x6 in. X 3/16 in. thick). These 350 watt units are at- tached to the under side of a 9 in. x 60 in. x % in. thick iron vulcanizing plate, and a temperature of about 650° F. maintained. Electric operation eliminates gas fumes and fire hazard, and is far more convenient. Sealing Wax Pots. — For applying large quantities of sealing wax, an electrically heated pot is more con- ''/enient than ordinary stick wax. Special Simplex de- vices made of spun copper and having the following capacities are in use : Vz pint 175 watt maximum 4-heat. Wz pint 300 watt maximum 4-heat. GENERAL APPLICATIONS 249 KSimplex Sealing- Wax Pot. Shelf Heaters. — Cutler-Hammer electrically heat- ed shelves form a means of heating ovens already built or in use. The shelves form separate units, which may be mounted in any oven of similar dimensions. They are suitable for use in incubators, lacquering C. H. Self Heater. ovens, plate warmers, evaporating and drying closets and laboratory cabinets. The shelves are of perfor- ated sheet metal, mounted on iron frame work, with the heating units inside. The standard sizes and capacities of these heaters are as follows : ngth. —Size in Inches Width. Th ickness. Maximum Watts. Number of Heats. 12 6 iy2 200 1 16 8 1^ 350 1 20 10 1^ 550 1 24 12 1% 75'0 3 24 16 1% 1,000 3 30 20 11/2 1,500 3 Shoe Relaster. — The Fern Company of Baltimore has placed an 80 watt relasting iron on the market for the use of the retail shoe trade. This device is used for smoothing out wrinkles, creases, and irregularities in shoes and otherwise improving their appearance. Shoe Machinery. — Electric heat has been applied to various machines in shoe factories with marked suc- cess. The following table shows various applications of electric heat to standard shoe machinery. 250 ELECTRIC HEATING Electrically Heated Shoe Machinery. No. of Application. Heating Unfts. Machine. Lining Cementer Knurling machine Knurl holder Stitcher Wax pot Stitcher Take-up Stitcher Truck on wax pot Stitcher Shuttle Patent leather repairer.... Wax receptacle... Stitcher (old) Take-up Stitcher (old) Shuttle Stitcher (old) Wax pot 2 Stamper Turret 2 Embossing machine Die holder 2 Embossing machine Paste 1 Upper leather stamping Machine Die Holder .... Indenter and burnisher.... Knurl holder . Welter Wax pot Welter Looper Welter Tension Welter Thread tube .... Embosser Die Holder .... Goodyear stitch burnisher. Knurl holder . . Bobbin winder Wax pot "Expedite" Burnishing iron "Expedite" , Wax pot Toe softening machine Boiler Solder Pots. — For heating and maintaining correct temperature for soldering operations, electrically heated pots are ideal. They are much cleaner, safer Wattage of Each Unit. 200 126 75 250 63 150 63 200 126 75 182 121 38 200 126 75 182 75 38 300 75 100 425 200 750 Westinghouse S'older Pot. and simpler to operate than the ordinary charcoal or gasoline heated pots. The standard Simplex pots have the following sizes and capacities : 5%" xiy^" deep 4 pounds capacity 200 watts three-heat. &%" X IVi" deep 10 pounds capacity 440 watts three-heat. 7%"xl^" deep 20 pounds capacity 825 watts three-heat. The standard American pots have the following capacities : 5 pounds capacity 400 watts three-heat. 10 pounds capacity 575 watts three-heat. 20 pounds capacity 975 watts three-heat. 50 pounds capacity 1500 watts three-heat. GENERAL APPLICATIONS 251 Soldering Irons. — Electric soldering irons de- signed for intermittent use are manufactured in sizes varying from 12 ounces to 3 pounds, and consuming from 75 watts to 350 watts, respectively. The Simplex G. E. Soldering- Iron. automatic stand, which cuts oft one-half the current when the iron is placed upon it, prevents the iron be- coming overheated when not in use. Solution Tanks. — The General Electric Company has devised a means of heating solution tanks with its cartridge units. One 3000 watt installation applied to a tank of 7/16 in. cast iron and having inside dimen- sions of 18 in. X 18 in. x 14 in., is said to bring a full tank of water to boil in about thirty minutes. Sterilizers. — The application of electricity to the heating of sterilizers offers a profitable market for energy in nearly every community. All modern hos- Westinghouse Instrument Sterilizer. pitals, Operating rooms, and dental offices are equipped with sterilizing devices, and the cleanliness, con- venience, and healthfulness afforded by electrically heated apparatus appeals to the physician or dentist and creates a favorable impression among his patients. 552 SLSCTRIC hii:atl\(; American Sterilizer Installation. (Left to right — In- strument, Water, Utensil, and Dressing- Sterilizers.) For complete sterilization, dressings are kept un- der a steam pressure of 15 pounds for about 20 min- utes. AVater is maintained at 250° F. in closed cham- bers for approximately the same period, whereas uten- sils and instruments are submerged in boiling water for about 15 minutes. Several makes of electrically heated sterilizers are now available. Small instrument sterilizers are made by the Westinghouse, Simplex, Cutler-Hammer, and other heating manufacturers. The American Sterilizer Company makes a complete line of electrically heated apparatus of this character, and the accompanying tables gives the sizes, capacities, and operating fea- tures of some of its sterilizers : Diam. Length Kw. Inches. Inches. Cap. 9 19 3 12 20 6 14 99 6 16 24 6 16 30 6 16 36 12 Dressing Sterilizers. Time and Energy Required for One Sterilization. Initial Temp. 150° F. Minutes Minutes Kw -hr. High Heat. Low Heat. Consumed. 14.5 20 .97 13 20 1.8 16.5 20 2.12 18.5 2i0 2.32 21 20 2.6 15.5 20 4.1 GENERAL APPLICATIONS 253 AVater Sterilizers. Gallons Capacity Kw. Capacity Time Steri] ana lunerg-y jrtequirea lor une lization. Initial Temp. 150° F. per per Minutes Minutes Kw -hr. Reservoir. Reservoir High Heat Low Heat. Consumed. 6 3 40 20 2.25 8 3 44 20 2.45 10 6 30 20 3.5 15 6 40.5 20 4.52 20 12 29.5 20 6.86. 25 12 31.5 20 7.26 35 18 32 20 11.1 Utensil Sterilisers. Time an d Energy Required forO ne Sterilization. Initial Temp. 150° F. 4" of Water. Minutes Minutes Kw -hr. Dimens ions in Inches. Kw. High Low Con- Deptli. Width. Length. Cap. Heat Heat, sumod. 16 15 2(0 6 14 15 1.75 20 20 24 6 25 15 2.87 20 24 30 12 37 15 4,1 24 24 30 12 . . Instrument Sterilizers. Time and Energy Required forO ne Sterilization. Initial Temp. 150° F. 2" of Water. Minutes Minutes Kw -hr. Dimensions in Ii nches. Kw. High Low Con- Deptli. Width. Leng-th. Cap. Heat Heat, sumed. 6 8 16 3 7.5 15 .55 6 10 20 3 9.5 15 .66 7 12 18 6 6.5 15 .98 7 12 22 6 8 15 1.19 9 12 18 6 6 15 1. 9 12 22 6 8 15 1.2 It should be observed that the energy consump- tions and time required for sterilization is based in each case on the use of water with an initial temper- ature of 150° F. If water at lower temperature is used the time and energy consumption will naturally be in- creased. The heating units employed are made by the concern solely for its own use. The 3 kw. units have three-heat control and the 6 kw. units have seven heat control. Sweating-On Machines. — An application typical of the advantage of electric heat over the open gas flame is that of the sweating-on machine for mounting cop- per electrotype shells upon type metal blocks. The block is placed upon the heated plate until the solder foil is melted and the block with the shell upon it is then pressed firmly together and allowed to cool. Cut- 254 ELECTRIC HEATING ler-Hammer heating elements applied to machines of this character are said to produce work superior in every way to gas heated apparatus. Test Tube Heaters. — For laboratory use the Sim- plex test tube heater is convenient. It consists of an electrically heated grooved casting slightly inclined from the perpendicular, against which the test tubes may be rested. The standard size of this heater is 5 in. X 7% in., and consumes 500 watts. Thread Waxer Heater. — A wax receptacle of a stitching machine may be heated electrically by attach- ing a low wattage unit to the bottom. A number of these heaters are in successful use. They eliminate all the dangers and discomforts of gas operation and are far more convenient and cleanly. Tire Vulcanizers. — For light automobile tire re- pairs the electric vulcanizer is ideal. Sand blisters, cuts and stone bruises can be repaired without remov- ing the tire, and as the work can be done promptly with a handy device of this kind, it will save much tire expense. The heat is evenly distributed over the surface and the work may be done neatly and quickly. Shaler Type C Inside Casing Form. S'haler Type E Tube Vulcanizer. The C. A. Shaler Co. manufactures a complete line of electrically heated vulcanizing forms, which it claims to be equal or superior to its steam devices. Some of the advantages set forth are simplicity, porta- bility, quick heating, safety and non-confliction with any garage regulations. Each device may be pur- chased separately, attached to any work bench, and used for its own distinct class of work. The capacities of the standard devices are as follows : GENERAL APPLICATIONS 255 Type A — Outside casing form 70 watts Type C — Inside casing form 80 watts Type E — "Gang" or multi-tube form (4%" x 24") • • • • 200 watts The Westinghouse automobile tire vulcanizer con- sumes a maximum of 200 watts. It is furnished with a 15-point rheostat, a thermometer, and a flexible cord. \i^ Westinghouse Outside Casing Shaler Type A Outside Casing Vulcanizing Outfit. Form. Varnish Tank Heater. — A well-lagged varnish tank 5 ft. high and 3 ft. in diameter, located near the roof of a factory, and used for spraying automobile bodies, has been heated by three 3-heat, 900-watt cartridge units for some time. The units are placed in a 10 in. X 6 in. X 3 in. box of sand, mounted j^ in. from the bottom of the tank, and the leads are brought out through a }i in. conduit. Velvet Marking Iron. — A 150 watt General Elec- tric iron having a body 1 in. square by 6 in. long and a bottom surface % in. wide by 6 in. long, is being used by the J. B. Martin Co. of Norwich, Conn., for marking letters and numbers on velvet cloth. A gummed cloth label is cemented in place by the heat and pressure ct the iron. Water Stills. — Electrically heated water stills equipped with General Electric heating units have been developed by the Barnstead Water Still Company of Boston. It is claimed by the manufacturers that a 2400 watt still will provide one gallon of distilled water per hour. 256 ELECTRIC HEATING E. & A. Barnstead Type L Water Still. Wax Burning-In Irons. — Electrically heated burn- ing-in irons are useful in furniture factories and stores for burning in wax. They are usually made in one pound sizes and are similar to soldering irons in de- sign. G. K. Wax Knife Heater. Wax Knife Heater. — General Electric wax knife heaters are superior to all fuel heated devices used by cabinet finishers. The standard type is similar to a 4-inch disc stove, consumes 180 watts and is designed GENERAL APPLICATIONS 257 with an insulating cover, under which the knife is placed. Weight Reducing Cabinet. — A galvanized iron cabinet 18 in. in diameter, lined v^ith %. in. asbestos, has been equipped by the General Electric Company with two of its tubular type 500 watt heating units. Arrangement is made for heat regulation so that the attendant may vary the temperature to suit the pa- tient's needs. Yarn Conditioning Oven. — This device is manu- factured by the Tillotson Humidifier Company of Providence, R. I. It is used for measuring the mois- ture in yarns by v^eighing before and after drying. It is well insulated and thermostatically controlled. The oven is heated with two General Electric 600 watt units. CHAPTER XVII RATES FOR HEATING SERVICE. Establishing of Rates. — Electric heating service usually differs from lighting and motor service in its value to the user and in the character of load it adds to the central station lines. If the load created by any class of service is sufficiently attractive to warrant the central station in making rates for it that are equal to or less than its value to the user, it is apparent that an ideal condition exists. If the rate is of necessity higher than the customer is justified in paying for the service rendered, business of such character is not de- veloped, and the buyer is forced to obtain the same or equivalent service elsewhere at a less cost. On the other hand, if the rate must be made so low to obtain the customer's business, that the additional expense involved is greater than the additional income secured, the central station would not be justified in making such a rate. Heating Loads. — The character of heating loads varies widely on account of the diversity of application. From an operating standpoint, they are usually more attractive than other classes of load. With few excep- tions they are non-inductive. As they generally oper- ate over long hour periods, they tend to improve the central station load factors. Fluctuations of the cur- rent demand are less marked, and as many electrically heated appliances naturally take, or can be made to take, energy only during off-peak hours, the advan- tages are obvious. The opportunity for building up cooking and heating loads along existing residential and rural lines, which have heretofore required enor- mous investment in proportion to gross income, is apparent. , Rate Maker's Difficulties. — Many central station managers, realizing the profitable nature of the electric RATES FOR HEATING SERVICE 259 heating business and the demand for such rates as will foster its development, have been anxious to make tariff revisions, but have been undecided as to the proper course to pursue by the apparent adverse atti- tude of press, public and the various regulating bodies. x^s a whole, the public is notoriously ill-informed on central station rate making principles, and is prone to criticise the motives actuating those who make rates for certain classes of service lower than established rates for other classes. Furthermore, the attitude of the public has often been reflected in the actions and decisions of public service commissions. The fear of criticism, and the dread of establishing harmful prece- dents that might be used against them, deter many responsible concerns from making rates designed to attract new and profitable business, in spite of their positive convictions that such action would be produc- tive of good for those directly concerned, as well as for the public at large. It may be observed that the fear of popular criti- cism and the dread of having all service rates reduced by commission rulings, in proportion as individual rates are lowered, are for the most part unfounded. Any downward revision that may tend to improve living conditions, develop new industries, or result in greater good for a greater number, must eventually meet with universal favor. On the other hand, harsh criticism must sooner or later come upon those who do not offer their customers the benefit of such rates as they can well afford and as will make for their mutual welfare. N. E. L. A. Rate Principles. — The six principles set forth in the 1915 report of the Rate Research Com- mittee of the National Electric Light Association are really the basis of intelligent rate making in the elec- tric industry, as well as in the railroad and other in- dustries. **(1) The total net income of the company must be enough and no more than enough to give a fair return on the investment and attract capital freely to the enterprise. The gross earnings from the sale of 260 ELECTRIC HEATING the product must therefore be sufficient to cover all necessary expenses of operation, including taxes, bad debts, etc., a reserve for renewals and contingencies, interest at current rates and a reasonable profit in ad- dition. "(2) When conditions are the same, rates to dif- ferent customers or classes should be the same, but need not necessarily be the same when conditions are diflferent. ''(3) No rate should be below the bare cost, i. e., below the expense involved by adding that customer or class, including a fair return on any investment added or used exclusively for that customer or class. "(4) Rates should be such that as many customers as possible may be served at as low rates as possible, and yet the business as a whole furnish a fair return on all the investment. ''(5) No rate can be above the value of service, otherwise the customer will not take it. "(6) While cutomers whose circumstances *are alike should pay the same rates, it is not necessary that customers whose circumstances are unlike in re- spect to the amount their class can afiford to pay, should be asked to pay the same percentage on the investment they use jointly, especially when they would not take the service if asked to pay such rates, but, on the other hand, would take the service and pay something toward the fair return on the whole investment if offered rates they could afford to pay. Application of Principles to Heating Rates. — It is apparent that in applying the Rate Committee's prin- ciples to the establishment of rates designed to develop certain heating loads, the central station is justified in making rates based upon the actual cost of supply- ing the service, plus a reasonable return upon the ad- ditional portion of the investment required to supply it. It is not essential that the income derived from the application of a rate shall be adequate to earn a re- turn upon the total plant investment involved in sup- plying it. RATES FOR HEATING SERVICE 261 Each central station company must decide for itself what rates it shall adopt, because the matter is one that naturally depends almost entirely on local conditions. It is obvious that the present tendency is toward wholesale rather than retail energy supply and rates must be based accordingly. The fact should be kept in mind in all considerations of rate matters that a mere statement of rate per kilowatt hour does not mean very much. The individuals who have their money invested are much more interested in annual returns than in hourly revenues. APPENDIX. Containing References and Tables. Eleetrif Heating Mauufactiireri>(. Advance Machinery Co Toledo, Ohio Glue cookers and pots. American Electric Heater Co Detroit, Mich, Domestic cooking and heating devices. Industrial heating apparatus. American Ironing Machine Co.. 166 No. Michigan Ave., Chicago Simplex ironing machines. American Laundry Mach. Co Cincinnati. Ohio Mangles. Armstrong Cork & Insulation Co Cincinnati, Ohio Heat insulating materials Barnstead Water Still Co Boston, Mass. Water stills. C. A. Shaler Co Waupun, Wis. Vulcanizers. Chicago Dryer Co 624 So. Wabash Ave., Chicago Clothes dryers. C. H. Sharp Mfg. Co 1312 E. 12th St., Los Angeles Electric ranges. C. L. McBride Mfg. Co Toledo, Ohio Glove stretchers and laying-off boards. Coin Machine Mfg. Co Portland, Ore. Induction water heaters. Induction linotype pots, Cutler-Hammer Mfg. Co 144th St. and Southern Blvd., N. Y. Industrial heating apparatus. Domestic heating devices. C. W. Leavitt & Co Cortlandt Bldg., New York, N, Y. Girod steel furnaces, Driver-Harris Wire Co Harrison, N. J. Resistance wire. Efficiency Products Co Rialto Bldg., San Francisco Water heaters. Eimer & Amend Co 205 Third Ave., New York, N. Y. Industrial and laboratory heating devices. Electric Sales Corporation 418 Union St., Seattle, Wash. "Apfel" Water Heaters. Elec+ric Sales Service Co 109 Stevenson St., San Francisco 'Therm Elect" water heaters. Bacteriological incubators. Electric Specialty Co Salt Lake City, Utah Chicken incubators and brooders. Electro Hatch Incubator Co Petaluma, Cal. Chicken incubators and brooders. Estate Stove Company Hamilton, Ohio Domestic ranges. General Electric Co Schenectady, N. Y. Domestic heating and cooking devices. , Hotel and domestic ranges. Industrial heating devices, , Geuder, Paschke & Frey Co Milwaukee, Wis, Butt welders. Globe Stove & Range Co ^ Kokomo, Ind. Domestic ranges. Good Housekeeping Cooker Co Berkeley, Cal. Automatic cookers and water heaters. 264 APPENDIX Hamilton & Hansel! 17 Battery Place, New York Rennerfelt furnaces. Hoskins Manufacturing Co Detroit, Mich. Small furnaces and heating devices. Hospital Supply Co 55 Fifth Ave., New York Sterilizers. . Hotpoint Electric Heating- Co Ontario. Cal. Domestic heating and cooking devices. Electric ranges. Hughes Electric Heating Co 211 W. Schiller St., Chicago Domestic and commercial cooking devices. Bake ovens, etc. H. W. Johns-Manville Co New York, N. Y. Heat insulating materials. James L. Gibney & Bro Philadelphia Vulcanizers. James B. Clow & Sons 342 Franklin St., Chicago Bath cabinets. Landers, Frary & Clark New Britain, Conn. Domestic heating and cooking devices. Lee Electric Radiator Co 335 Wells St., Chicago, 111. Water heaters and radiators. Lincoln Electric Co E. 38th St. and Kelley Ave., Cleveland Arc Welders. Majestic Electric Development Co 428 O'Farrell St., S. F. Radiant air heaters. Michigan Stove Co Detroit, Mich. Domestic ranges. National Electric Utilities Co 103 Park Ave., N. Y. Hotel and domestic ranges. National Electric Welder Co Warren, Ohio Spot, butt and seam welders. Pelton & Crane Co 244 Harper Ave., Detroit, Mich. Furnaces for jewelers and opticians. Petaluma Incubator Co Petaluma, Cal Chicken incubators and brooders. Prometheus Electric Co 232 E. Third St., New York Sterilizers, radiators, etc. Presto Electric Co 323 Geary St., San Francisco Dental heating devices. Rathbone, Sard & Co Albany, N. Y. Domestic ranges. Rutenber Electric Co Logansport. Ind. Domestic ranges. Scanlan-Morris Co Madison, Wis. Sterilizers. Siemund. Wenzel Electric Welding Co 30 Church St., N. Y. Welding machines. Simplex Electric Heating Co Cambridge, Mass Domestic heating and cooking devices. Hotel and domestic ranges. Industrial heating devices. Snyder Electric Furnace Co Chicago, 111 Steel furnaces. Standard Electric Stove Co 1718 No. 12th St., Toledo. O. Domestic ranges. Thomson Electric Welder Co Warren, Ohio Welding machines. Union Fibre Co Winona, Minn. Heat insulating materials United Sales Company Hobart Bldg., San Francisco. Automatic water faucets. United States Steel Corporation Hoboken, N. J. Heroult steel furnaces. Vulcan Electric Heating Co 107 W. 13th St., New York, N. Y. Branding irons. Wenborne-Karpen Dryer Co 900 Michigan Ave., Chicago Varnish dryers. APPENDIX 265 Westinghouse Electric & Mfg. Co East Pittsburgh, Pa. Domestic heating and cooking devices. Domestic ranges. Industrial heating devices. Wilmot, Castle Co Rochester, N. Y. Sterilizers. Winfield Electric Welding Machine Co Warren, Ohio Welding machines. Wm. B. Berry & Co 79 North St., Boston, Mass. Corn poppers and peanut roasters. Conversion Data. kw -hr. = 3412 B.t.u. watthour == 3.412 B.t.u. wattminute = .0568 B.t.u. wattsecond = .0009477 B.t.u. large calorie =i 3.968 B.t.u. kw -hr. = 859.975 large cal- ories. 1 watthour = .859975 large calorie. 1 wattminute = .01433 large calorie. 1 wattsecond = .000239 large calorie. 1 gallon (U. S.) water contains 231 cu. in. or .1337 cu. ft. 1 cu. in. of water contains .00433 gal. and weighs .0361 lb. 1 cu. ft. of water contains 7.48 gal., and weighs 62.428 lb. 1 pound of water = 27.68 cu. in. 1 pound of water ==z. 958 pint. 1 kilogram of water = 1000 cu. cm. 1 kilogram of water = 1.0567 quarts. 1 B.t.u = .000293 kw -hr. 1 B.t.u. = .293027 watthour. 1 B.t.u = 17.58 wattminutes. 1 B.t.u.=r 1054.9 wattseconds 1 B.t.u. = .25199 large calorie. 1 large calorie = .001163 kw. hr. 1 large calorie i= 1.163 watt- hours. 1 large calorie = 69.769 watt- minutes. 1 large calorie == 4186.17 watt- seconds. 1 large calorie = 1000 small calories. 1 gram of water = 1 cubic cen- timeter. 1 pounu of water :=: 453.592 cu. cm 1 kilogram of water = 61.023 cu. in, 1 kilogram of water :== .035314 cu. ft. Resistance of Conductors at Various Temperatures. Rt = Ro (1 + xt). Rt ^ resistance at temperature t. Rft=r resistance at temperature given in standard tables. X =: temperature co-efflcient. (Table I.) t = difference between R^, and Rt. Table 1 — Relative Resistance and Temperature Coefficient. Relative Resistance Temp. Coef. Pure Metals. in per cent. Fahrenheit (x) Silver annealed 92.5 .00222 Copper annealed 97.5 .(00242 Copper (Standard) 100.0 Gold 99.9 per cent 138 .00210 Aluminum 99 per cent 161 .00235 Zinc 362 .00226 Platinum annealed 565 .00137 iron 570 .00347 Nickel 778 .00345 Tin 828 .00245 Lead 1,280 .00228 Antimony 2,21(0 .00216 Mercury 5,930 .00044 Bismuth 8,220 .00197 Nichrome (alloy) .00024 266 APPENDIX Table II. — Relation of Load Factor aud KiloAvatt-Hoiir Cou- suinptlon. Load Factor per cent. 100 90 80 70 60 Kw-hr. per Year per kw, 8760 7884 7008 6132 5256 Kw-hr. per Month per kw. 730 657 584 511 438 Load Factor per cent &0 40 30 20 10 Kw-hr. per Year per kw. 4380 3504 2628 1752 876 Kw-hr. jier Month per kw. 365 292 219 146 73 Table III. — Relative Radiating and Reflectingr Power of Different Substances (Kent). Radiating or Absorbing Power. Lampblack 100 Water 100 Carbonate of lead 100 Writing paper 98 Ivory, jet, marble 93 to 98 Ordinary glass Ice Gum lac Silver-leaf on glass Cast iron, bright polished, Mercury, about Wrought iron, polished. . . , Zinc, polished Steel, polished Platinum polished Platinum, in sheet Tin Brass, cast, dead polished , Copper, varnished Brass, bright polished.... Copper, hammered Gold, plated , Gold on polished steel.... Silver, polished bright 90 85 72 27 25 23 23 19 17 24 17 15 11 14 Reflecting Power. 2 7 to 2 10 15 28 73 75 77 77 81 83 76 83 85 89 86 93 93 95 97 97 Table IV. — Transmission of Heat Through Plates and Tubes from Steam or Hot Water to Air. (Kent). (B.t.u. per hour per sq. ft. per degree Fahr. difference.) Copper, polishea 0327 Sheet-iron, ordinary 5662 Tin, polished 0440 Glass 5948 Zinc and brass, polished. .0491 Cast iron, new 6480 Tinned iron, polished.... .0858 Common steam-pipe, in- Sheet iron, polished 0920 ferred 6400 Sheet lead 1329 Cast and sheet iron,, Wood, building stone, and rusted 6868 brick 7358 Table V. — Boillus Points at Atmospheric Pressure 14.7 lb. per square inch. (Kent). Deg. F. Deg. F. Ether, sulphuric 100 Av. sea water 213.2 Carbon bisulphide 118 Saturated brine 226 Ammonia 140 Nitric acid 248 Chloroform 140 Oil of turpentine 315 Bromine 145 Phosphorus 554 Wood spirit 150 Sulphur 570 Alcohol 173 Sulphuris acid 590 Benzine 176 Linseed oil 597 Water 212 Mercury 676 The boiling points of liquids increase as the pressure in- creases. The boiling point of water at any given pressure is the same as the temperature of saturated steam of the same pressure. APPENDIX 267 Tabh Substance. Bismuth Cast iron, gray Cast iron, white Lead Tin 25.65 Zinc 50.63 Ice 144. VI. — Latent Latent Heat of Fusion in B.t.u. . . . 22.75 ... 41.4 . . . 59.4 9.66 Heat of FuMiou. Latent Heal of Fusion Substance. in B.t.u. Silver 37.93 Beeswax 76.14 Paraffine 63.27 Spermaceti 66.56 Phosphorus 9.06 Sulphur 16.86 Table VII. — Meltlng-PointH of Various Substances, T>eg. F. Sulpliurous acid Carbonic acid . Mercury Bromine Turpentine — 148 — 108 — 39 • + . 14 9.5 Hyponitric acid 16 Ice 32 Nitro-g-lycerine 45 Tallow 92 Phosphorus 112 Acetic acid 113 Stearine 109 to 120 Spermaceti . . ." 120 Marg-aric acid 131 to 140 Potassium 136 to 144 Wax 142 to 154 Stearic acid 158 Sodium 194 to 208 Alloy. 3 lead, 2 tin and 1 bismuth 199 Iodine 225 Sulphur 239 (Kent). Deg. F. Alloy, 1 tin, 1 lead ... 370 to 466 Tin 442 to 446 Cadmium 442 Bismuth 504 to 507 Lead 608 to 618 Zinc 680 to 779 Antimony 810 to 1150 Aluminum 1157 Magnesium 1200 Calcium Full red heat Bronze 1692 Silver 1733 to 1873 Potassium sulphate 1859 Gold 1913 to 2282 Copper 1929 to 1996 Cast iron, white. .. 1922 to 2075 Cast iron, gray 2012 to 2228 Steel 2372 to 2532 Steel hard, 2570; mild 2687 "Wrought iron 2732 to 2912 Palladium 2732 Platinum 3227 Alloy. IVz tin, 1 lead 334 Cobalt, nickel, and manganese, fusible in highest heat of a forge. Tungsten and chromium, not fusible in forge, but soften and agglomerate. Platinum and iridium, fusible only before the oxyliydrogen blowpipe. Table VIII. — Specific Gravity of Substances. Wt. of substance. S-p.Gr. =-. Wt. Substance. Metals: Aluminum . . . of equal bulk of pure water. Average Sp. Gr. 2 67 Pounds per cu. ft. 166 5 Antimony . . . . Bismuth 6.76 ... 9 82 421.6 612 4 Brass: Copper 80 -f Zinc) 20 30 . 40 50 . r, 95 to 5 to 8 &0 536 3 70 8 40 523 8 60 8 36 521 3 50 8.20 511.4 Bronze: Coppe Tin, Cadimum 80 20 8.53 8.53 8 65 552.0 552.0 539 Gold, pure . . . . 19 258 1200 9 Copper Iron, Cast . . . . Iron, Wrought 8.853 7.218 7 70 552. 450. 480 Lead 11.38 709.7 Manganese . . . 8. 499. Magnesium . . . 1 75 109 Mercury 32° 13 62 849 3 Mercury 60° . . 13.58 846.8 268 APPENDIX Average Pounds per Substance. Sp. Gr. cu. ft. Mercury, 212° 13.38 834.4 Nickel 8.8 548.7 Platinum 21.5 1347.0 Silver 10.505 655.1 Steel 7.854 489.6 Tin 7.35 458.3 Zinc 7.00 436.5 Wood: Ebony 1.23 76 Oak, Live 1.11 69 Cedar 62 39 Pine, White 45 28 Pine, Yellow 61 38 Cork 24 15 Stoues, Brick, Cement, etc.: Asphaltum 1.39 87 Brick, Soft 1.6 100 Brick, Common 1.79 112 Brick, Hard 2.0 125 Brick, Pressed 2.16 135 Brick, Fire 2.32 145 Brickwork in mortar 1.6 100 Brickwork in cement 1.79 112 Cement, Rosendale, loose 96 60 Cement, Portland, loose 1.25 78 Clay 2.16 135 Concrete 2.08 130 Earth, loose 1.22 76 Earth, rammed 1.60 100 Emery 4. 250 Glass 2.63 164 Glass, flint 3.02 188 Gneiss 2.64 165 Granite 2.64 165 Gravel 1.76 110 Gypsum 2.24 140 Hornblende 3.36 210 Lime, quick, in bulk 84 53 Limestone 2.96 185 Magnesia, Carbonate 2.4 150 Marble 2.72 170 Masonry, dry rubble 2.40 150 Masonry, dressed 2.56 160 Mortar 1.52 95 Pitch 1.15 72 Plaster of Paris 1.23 77 Quartz 2.64 165 Sand 1.60 100 Sandstone 2.32 145 Slate 2.80 175 Stone, various 2.78 168 Trap 3.06 185 Tile 1.84 115 Soapstone 2.73 170 Liquids (at 60° F.): Acid, Muriatic 1.200 Acid, Nitric 1.217 Acid, Sulphuric 1.849 Alcohol, pure 794 Alcohol, 95