# Popular Mechanics/Volume 50/Issue 5/The New Age of Electric Heat

Layout 2
The Latest Thing in Electric Welding, the Atomic-Hydrogen Process; Hydrogen Fed to the Arc Has Its Molecules Broken into Atoms, Which, in Recombining, Produce Intense Heat
By CALVIN FRAZER
WHEN you tell the average person that electrical heating has made revolutionary progress within the past few years, he thinks of his domestic furnace, now burning coal, oil or natural gas, and asks whether the time has come to discard these fuels for something better. Let us therefore explain that the new era of electric heat does not yet affect to any marked extent the problem of keeping your house warm in winter.
The "house without a chimney" flourishes on certain reclamation projects in the west, where cheap electricity is a by-product of irrigation under the auspices of a paternal government. It prevails to some extent in Europe, where water-power electricity is equally cheap. Electric "heat reservoirs" have been installed in many Swiss and German houses. These are huge tile-incased stoves, of ancient pattern but with electric heating elements placed inside instead of the usual coal or wood fires, to heat the heavy slabs of slate or soapstone that compose the walls. Current is supplied to these devices during the off-peak hours of the night at low rates, and they store enough heat to last all day. A few "all-electric" houses in England are heated on a similar basis, hot water being used to retain the heat.
Generally speaking, however, the heating of entire houses by electricity does not yet loom on the horizon, though small portable electric heaters for single room—especially bathrooms and bedrooms—are common. Even as applied to ordinary household cooking, electric heat is still unable to compete with coal and gas in most communities. Its uses in the home are mainly in small appliances that consume but little current, including toasters. ​grills, chafing dishes, percolators, flatirons, curling irons, bed warmers, hair driers, and so on. These domestic conveniences are steadily increasing in number, and their advent may be said to mark a new epoch in housekeeping, but it is in the industrial field that the amount of electric energy used as heat has lately become truly enormous. A well-known engineer has recently predicted that before the year 1935 we shall see as much electricity used industrially in this country for heating as is used in turning the wheels of machinery.
Putting Together a Steel Building by the New Process That Promises to Banish the Rat-a-Tat-Tat of Pneumatic Riveting Hammers
This development was undreamed of a generation ago. Look back to the year 1882, and you find Edison establishing in New York city the first public plant for supplying electricity. A 200-kilowatt generator sufficed for its needs and the output was devoted entirely to lighting. A few years later the motor load began to figure in central-station operations, with the advent of desk fans in offices. Electric elevators and other applications of the motor followed. By the early nineties of the last century, electricity was driving a large variety of machines, electric railways were rapidly multiplying, and the business of producing and selling electric current had come to be known as the electric-light and power industry, a name that it still retains. In the statistics of the industry, the part of the output used for lighting is usually segregated, while that used for driving motors, for heating and for electrochemical purposes is lumped together under the head of power. Not until the second decade of the present century did the central stations begin to supply more energy for power than for lighting, and only within the past six or eight years did the portion of the former applied to industrial heating begin to bulk large.
Let us now see how this new electrical giant is serving the needs of industry.
​There are two ways in which electricity can be used for heating: the arc method and the resistance method. The arc is, of course, a special case of electric resistance (the air or other gas between the electrodes being the resistant medium) but it always produces intense heat, while the resistance of a solid conductor can be adapted to producing any temperature desired. The arc method is therefore confined to the melting of metals, including iron, steel, brass, etc., and to welding. In using the resistance method, the electric current may be sent directly through the material to be heated, produced by induction in this material, or sent through a heating unit separate from the material to be heated. The last of these three processes is the most versatile and the most widely used.
Thawing Machine on the Alaska Railroad; a Small Electric Furnace Used to Glaze the Porcelain on Artificial Teeth at a Temperature of 1,945 Degrees, and Furnaces Making Abrasives.
Electric heating costs more, per unit of heat produced, than heating by the use of fuel, but it offers many striking advantages over the latter process, and it is also in many cases much cheaper in the long run on account of incidental economies realized in its use. Heating with fuel means combustion, and combustion means that a great amount of air must be heated, much of this heat escaping up the chimney; that undesirable fumes and soot are produced, and that exact regulation of temperature is difficult or impossible. Electric heating is not a combustion process; it requires no air; produces no soot or fuel gases, and can be regulated as perfectly and easily in ordinary industrial work as under the conditions of the electrical laboratory. One of the many incidental advantages of electric heat is that it can generally be used without raising the temperature of the air in workrooms, and thus it is not, like combustion heating, a source of discomfort to the workmen.
No type of equip ​ment for applying electric heat has had a more spectacular success in the industrial world than the electric furnace, of which there are several varieties, some working on the arc principle and some on the resistance principle. Among the main uses of the electric furnace are the melting and the heat-treatment of metals. In the iron and steel industry, for example, a high grade of pig iron is produced by the use of the electric furnace in place of the blast furnace. A much more important application, however, is in the making of steel. In the electric furnace, the charge is melted in a closed chamber. There is no oxidation, no contamination from fuel gases, and the temperature can always be perfectly controlled. Thus, steel of crucible quality can be made much more rapidly than by the crucible process. The electric furnace is used especially for making the various alloy steels, and for super-refining steel made by the open-hearth and Bessemer processes. It is also widely used in melting steel for castings. Lastly the electric-heat-treatment furnace provides a far more perfect control of temperatures than any fuel-heated furnace, and is therefore the ideal means of annealing, hardening and tempering metal.
Pouring the Molten Charge from an Electric Steel Furnace: a Large Percentage of All the Energy Generated at Niagara Falls Is Used as Heat in Various Manufacturing Processes.
The triumph of electric steel dates essentially from the year 1915, when the demand for high-grade steel was greatly stimulated by the requirements of warfare. Since that time, electric heat has come into extensive use for the melting and heat treatment of brass and other nonferrous metals. In a long list of metallurgical operations, electricity introduces the exactness of laboratory practice into the workshop and at the same time minimizes the need of skilled labor.
The most romantic feats of the electric furnace are those achieved by the use of temperatures unattainable by fuel-heated furnaces, as, for example, in the manufacture of artificial abrasives and in the fixation of atmospheric nitrogen. Carborundum, of which thousands of tons are produced annually at Niagara, owes its existence entirely to electric heat. All the aluminum made in the world is produced in electric furnaces. The same is true of calcium carbide, calcium cyanamide, alu​mina and a large number of other highly useful compounds.
The electric oven, used for baking, drying, etc., at temperatures lower than those of the electric furnace, offers similar advantages of accurate temperature control, facility of operation and freedom from the contaminating effects of combustion. These ovens are now used in the preparation of hundreds of important products, ranging from pies and doughnuts to glassware, enamel ware, motor armatures, piano keys and watch dials. Chinaware is fired more easily and successfully in the electric oven than in combustion ovens, as the former provides a perfectly uniform temperature in all parts of the heating chamber, and any desired temperature can be exactly reproduced for each batch fired.
The electric "lehr" or annealing oven has recently come to the front in the glass industry. The quality of the glass annealed in it has proved so superior that many large users of glassware now specify in their orders, "must be annealed by electric lehr." One nationally known maker of ginger ale, after experiencing an average bottle breakage of two per cent in his filling machines, made the astonishing record of filling and capping 720.000 electrically annealed bottles, with the loss of only four from the entire lot!
Battery of Electric Babbitt Pots Used by a Street-Railway Company to Melt Metal to Be Poured into Car Bearings.
To describe, even briefly, all the applications of electric heat in industry would require a large book which would be out of date by the time it was published, as interesting new developments are cropping up every day. The following are a few random details of the story:
Electric heat is used to stimulate oil wells that are running dry. Heating coils are lowered into the well to melt the heavy-oil accumulation and permit it to flow freely.
The evenness of heat essential to the correct curing and vulcanizing of rubber is automatically obtained by the use of electric apparatus to produce steam. In this process, the operation is confined to a single self-contained unit and does away with all piping.
Power and light companies find it profitable to use electric heat in purifying transformer oil. The oil is placed in a rotating apparatus which separates the suspended carbonized particles. The application of heat then vaporizes the contained water and other impurities, leaving the oil in proper condition to be used again.
In the preparation of effervescent salts, electric heat is found to be the most effective means of expelling moisture. It is now widely applied to drugs that must be packed in a perfectly dry condition.
Electric melting pots attached to typesetting machines are a boon to the printing industry. With the even temperature thus secured, the operator's attention is no longer diverted at frequent intervals to watching the thermometer, and production is said to be increased from fifteen to twenty-five per cent. Moreover, the appearance of the typography is much improved, as a sharp, clear type face results from maintaining exactly the right casting temperature.
Electric heat is used with great ad​vantage to melt glue in the manufacture of paper boxes, shoes, furniture, books, pianos and automobiles. It is also the ideal means of melting lead and tin, as well as solder, babbitt and similar alloys. The electric melting pot maintains the correct temperature automatically, without the danger of burning and without slag.
Goggled to Protect His Eyes against the Glare of Molten Steel, the Attendant Tests the Charge to See If It Is Ready for Pouring; Electric Steel Is Expensive but Best.
The electric welding of steel and other metals began half a century ago, but it has lately assumed many new forms and has been applied to a great variety of purposes. One of its newer feats is to add metal to rails where they are worn at the joints without removing them from the track. Various automatic welding machines have come into use, especially for welding the seams of tubes and pipes. Electric arc welding has had sensational success during the last two or three years as a substitute for riveting in the construction of steel-frame buildings, and also in shipbuilding.
Another important application of welding is in the construction of airplane fuselages. Metal has practically displaced wood in American-built commercial planes because of the superior strength of special alloy tubing, with no appreciable difference in the weight of the completed machine. Tests of properly welded joints invariably show that the weld is stronger than the rest of the material.
"Heat it electrically." is the new watchword of industry.
INSECTS THAT DEVOUR INSECTS TO PROTECT PLANTS
Orchardists in South Africa have been calling upon California for supplies of a certain species of beetle that devours the troublesome mealy bugs attacking trees in Africa. Growers are attempting to cultivate the beetles and raise a large army of them against the mealy bugs.
GAS GUN LIKE FOUNTAIN PEN TO AID BANK CLERKS
Pen-Shaped Gas Holder for Repulsing Bandits; It Shoots Fumes Twelve Feet and More
Shaped like a fountain pen, a small container for gas fumes, to foil bandits, has a lever that shoots the vapors a distance of twelve feet and more. It is intended for the use of bank tellers, clerks and others, and is deceptive to an intruder as its appearance gives no indication of its purpose. The "pen" unscrews in the middle for the insertion of a gas cartridge.
IRON WIRE ACTS AS NERVE ACID TEST SHOWS
The expression, "he is a man of iron nerves," may be more true literally than has been supposed, an interesting series of tests just concluded by Prof. Ralph S. Lillie, of the University of Chicago, indicates. His experiments have revealed a striking similarity between nervous action, particularly heart action. and the behavior of iron wire in a nitric-acid bath. A pure iron wire, one to five centimeters long, was immersed in a nitric-acid solution of sixty to eighty per cent. A colorless film immediately formed over the wire and, if one end was scratched, a wave traveled rapidly along the wire. When a glass tube was placed in the acid, around one end of the wire, rhythmical waves passed the length of the piece at the rate of fourteen to 120 times a minute, depending upon the strength of the solution, the temperature and the length of the wire. Dr. Lillie concluded that a sort of battery was formed. The film, only one molecule in thickness, acquired an electrical charge negative to that of the wire. When the film was scratched, a current was set up which dissolved the film next to the bare spot. This continued until the bare spot, which was seen as a wave, had passed the length of the wire. The film forms again after the wave has passed. The influence of temperature, electrical polarization, concentration of acid and length of the wire, have been shown to be the same as their influence on living nerves.
HOUSE TRAVELS OVER THE SEA ON POWERFUL CRANE
A sturdy crane picked up a house and floated it several miles across the water to a new location in Rotterdam recently. The crane was part of the equipment of a powerful harbor vessel, used in wrecking, dredging and other heavy tasks.
Giving a House a Ride: Powerful Crane Carrying Dwelling across Stretch of Water to New Location at Rotterdam
UNIFORM AIRWAY MARKERS TO AID FLYING
Assistant Secretary of Commerce William P. MacCracken, Jr., and Art Goebel Examining Sample Markers Proposed for Use on the Airways of the Country to Guide Flyers
Department of commerce officials are endeavoring to induce the adoption of a uniform style of markers to guide flyers along the airways of the nation. Different colors will be used for different cross-country routes, and other distinguishing details will be employed, according to present plans, to make it easy for the pilots to tell where they are. When the proper form of markings has been decided upon, it is intended to have them widely displayed to make them known.
NEW WAY OF BUILDING WALL ELIMINATES PLASTERING
Greater economy, a saving of time, and other advantages, are claimed for a patented form of wall construction which leaves the interior in such a finished state that it is not necessary to use plaster. The essential feature of the method is its interlocking units which may be made of metal, concrete, fiber, gypsum or other materials suitable for wall construction. These units are molded in long channel shape and are set on end instead of being built up as the ordinary wall of blocks or of brick. The length of the channel depends upon the height of the story, it is two feet or more wide and has an interlocking flange that holds it to the channel placed next to it. The depth of the channel depends upon what thickness of wall is desired, and the interior of the unit forms a dead-air space which affords insulation or may be used for wires, pipes or other conduits. Where a column is desired for support, the space may be filled with concrete. When finished, the wall requires no stone or other covering on the inside, while the joints on the outside may be concealed beneath any appropriate form of finish.
FAKE PEARLS ARE REVEALED BY SPECIAL CAMERA
Using the Pearl-Inspecting Camera, and a Close View of Three Genuine Pearls Showing the Internal Structure
French experts have recently introduced a camera that takes pictures of the inside of pearls so that the genuine may be told from the imitation. Detailed views of the interior structure, and other points that are impossible to detect with the unaided eye, are said to be clearly revealed so that successful passing of the false for the gennine is not likely to occur after an examination with the instrument.
DEATH WHISPERS FROM QUARTZ KILL SMALL ANIMALS
Further interesting experiments with inaudible sound waves have been performed recently by Alfred L. Loomis, who causes a quartz crystal to produce vibrations at the rate of two and one-half million per second, called "death whispers," because they kill small organisms in water. In earlier experiments, he produced vibrations at the rate of three-quarters of a million per second. The more recent effects have been obtained with a tiny slab of quartz, less than an inch long, about three-eighths of an inch wide and one-sixteenth of an inch thick. Its high rate of vibration is partly due to its smaller size as compared with the other crystal. and to the more rapidly oscillating electric current to which it is submitted to cause vibrations. Plant and animal cells were killed by the violent stirring of their contents. The cell walls of the plants were not broken, as they were evidently too tough and strong, but the contents were seen to be swirled into a disorganized mass by the action of the weird whispers of death.
TONE TESTER LOCATES RADIO TROUBLES BY KEEN HEARING
Listening to radio programs through loud speakers, as many as 250 of them a day, is the task of Martin T. Olsen, a veteran in one of the most highly specialized activities in the world. He is a tone tester. Just as the tea taster's sense of taste has been developed to a point where he can detect the slightest difference in blend, so Olsen's ears can distinguish the least variation in pitch. The average person can tell the difference in tones or notes up to about 5,000 or 6,000 frequencies per second, scientists say, but Olsen, in a competitive test, demonstrated that he was able to distinguish notes at frequencies of over 10,000 cycles per second. During a broadcast program, he can usually tell if distortion or extraneous noise is the fault of the microphone, is in the station studio or if the interfering noise or faulty tone is caused by the set itself, and if so, where the trouble lies. His chief business is to listen to the loud speakers manufactured by a radio company to determine if they are up to the standard of the master model in tone and pitch. If they are not, Olsen's keen sense of hearing aids in locating the difficulty.
Martin T. Olsen, Testing Tone of Loud Speaker