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Dry Heat Storage
Oct.. 10.3o.l
CLJRRENTTorrcs.
54’
mercial development of aluminum products and the common use of vacuum devices have contributed to the extent of overcoming the It is now possible to purchase the difficulty of costly apparatus. so-called ” Alcoa ” in thin sheets, which readily take the curvature This material of a suitable cradle form without previous shaping. reflects over 80 per cent. of solar radiation, and may be used for years without dimming. As the loss of heat in the boiler at the focus of a solar-radiation appliance is the great obstacle to be provided against, the possibility of making cheap glass jackets enclosing high vacua like thermos bottles is the other great improveOf special ment. The author describes various kinds of apparatus. interest is that of a cooker for food in which the use of water was dispensed with in favor of “ Arochlor ” a nearly black liquid product This was made almost completely of the 11onsanto Chemical Co. absorptive of sun rays by adding- a small amount of lampblack in suspension. It does not boil below 3<5o deg. C. and evaporates scarcely at all at lower temperatures and is used directly in a Also, a flash solar boiler for vacuum jacketed glass focus tube. With the high efficiency and great simplicity power is described. of the arrangement Mr. Abbot computes that power can be had from the sun at not exceeding 0.5 cent per horsepower hour and still give a good return on the investment. Ii.
H.
0.
Dry Heat Storage.-( Ideating and Ventilating, \,‘ol. 36, No. 8.) Increased interest is being shown in the commercial possibilities of dry heat storage in which small lumps of magnetite are contained in refractory tubes and heated by electricity. This method is being employed in the heating of buildings and for drying. According to CASTOS Roux, writing m Revue Gene&e de 1’Electricite. the first industrial plant of this type was installed at the Chedde (Haute Savoie) works of the Cie. de Produits Chimiques et Electra-Metallurgiques Alais, Froges at Camargue, in 1936. This heater, directly connected to a 6,000 volt supply, absorbed 100 kw. and stored approximately ~,OOO,OOOB.T.U. in 6 tons of broken magnetite, heated to between 900' and I 100~ F. Satisfactory results were obtained in the drying of potassium chlorates and other salts, and a second high voltage heater was installed at Asnieres for heating offices and rooms for engineers of the Nord-Lumiere company. At Asnieres, about 4,158,ooo B.T.U. are stored during a charging period of rq hours, and the stored heat is utilized over the twenty-four hours. For use in small houses and flats, thermal storages operating on the same principle are made by compressing powdered magnetite in steel
CURRENT
TOPICS.
[J. F. I.
tubes lined with insulating material and surrounded by cast-iron blocks which contribute to the storage of heat. Magnetite has been chosen as the best material for this form of heat storage after estensive trials with many minerals. R. H. 0. Shadow of Ship Fires Torpedo.-( Commerce and Industry, Vol. XIX, No. ho-II.) A torpedo that would utilize the shadow of the enemy ship to blow up that vessel has been designed by JOHN HAYS HAMMOND, JR., of Gloucester, Mass. This is revealed in a patent (No. 2,164,916) awarded by the U. S. Patent Office to Mr. Hammond. The torpedo is photoelectrically operated. It travels deep under the surface of the water, turns suddenly upward when it comes in the shadow of the ship, and explodes under the ship’s bottom. In the top of the torpedo is a photoelectric cell. This is connected to an electrical system which controls the course and the explosion of the torpedo. When the torpedo is fired, natural daylight filtering through the water is focused on the photoelectric cell and the solenoid mechanism which controls the explosion is de-energized. However, as soon as the torpedo passes under the bottom of the ship, the light to the photoelectric cell is cut off by the shadow of the ship. This is ‘(noted” by the photoelectric cell. The mechanism controlling the course of the torpedo automatically changes so as to direct the torpedo upwardly against the bottom. At the same time the solenoid is energized to explode the torpedo under the ship. To prevent premature explosions, as when the torpedo may pass under some floating debris, there is included a delay action unit which makes it necessary for the photoelectric cell to be cut off from light for an appreciable period of time before the torpedo will esplode. R. I-I. 0.
CLJRRENTTorrcs.
54’
mercial development of aluminum products and the common use of vacuum devices have contributed to the extent of overcoming the It is now possible to purchase the difficulty of costly apparatus. so-called ” Alcoa ” in thin sheets, which readily take the curvature This material of a suitable cradle form without previous shaping. reflects over 80 per cent. of solar radiation, and may be used for years without dimming. As the loss of heat in the boiler at the focus of a solar-radiation appliance is the great obstacle to be provided against, the possibility of making cheap glass jackets enclosing high vacua like thermos bottles is the other great improveOf special ment. The author describes various kinds of apparatus. interest is that of a cooker for food in which the use of water was dispensed with in favor of “ Arochlor ” a nearly black liquid product This was made almost completely of the 11onsanto Chemical Co. absorptive of sun rays by adding- a small amount of lampblack in suspension. It does not boil below 3<5o deg. C. and evaporates scarcely at all at lower temperatures and is used directly in a Also, a flash solar boiler for vacuum jacketed glass focus tube. With the high efficiency and great simplicity power is described. of the arrangement Mr. Abbot computes that power can be had from the sun at not exceeding 0.5 cent per horsepower hour and still give a good return on the investment. Ii.
H.
0.
Dry Heat Storage.-( Ideating and Ventilating, \,‘ol. 36, No. 8.) Increased interest is being shown in the commercial possibilities of dry heat storage in which small lumps of magnetite are contained in refractory tubes and heated by electricity. This method is being employed in the heating of buildings and for drying. According to CASTOS Roux, writing m Revue Gene&e de 1’Electricite. the first industrial plant of this type was installed at the Chedde (Haute Savoie) works of the Cie. de Produits Chimiques et Electra-Metallurgiques Alais, Froges at Camargue, in 1936. This heater, directly connected to a 6,000 volt supply, absorbed 100 kw. and stored approximately ~,OOO,OOOB.T.U. in 6 tons of broken magnetite, heated to between 900' and I 100~ F. Satisfactory results were obtained in the drying of potassium chlorates and other salts, and a second high voltage heater was installed at Asnieres for heating offices and rooms for engineers of the Nord-Lumiere company. At Asnieres, about 4,158,ooo B.T.U. are stored during a charging period of rq hours, and the stored heat is utilized over the twenty-four hours. For use in small houses and flats, thermal storages operating on the same principle are made by compressing powdered magnetite in steel
CURRENT
TOPICS.
[J. F. I.
tubes lined with insulating material and surrounded by cast-iron blocks which contribute to the storage of heat. Magnetite has been chosen as the best material for this form of heat storage after estensive trials with many minerals. R. H. 0. Shadow of Ship Fires Torpedo.-( Commerce and Industry, Vol. XIX, No. ho-II.) A torpedo that would utilize the shadow of the enemy ship to blow up that vessel has been designed by JOHN HAYS HAMMOND, JR., of Gloucester, Mass. This is revealed in a patent (No. 2,164,916) awarded by the U. S. Patent Office to Mr. Hammond. The torpedo is photoelectrically operated. It travels deep under the surface of the water, turns suddenly upward when it comes in the shadow of the ship, and explodes under the ship’s bottom. In the top of the torpedo is a photoelectric cell. This is connected to an electrical system which controls the course and the explosion of the torpedo. When the torpedo is fired, natural daylight filtering through the water is focused on the photoelectric cell and the solenoid mechanism which controls the explosion is de-energized. However, as soon as the torpedo passes under the bottom of the ship, the light to the photoelectric cell is cut off by the shadow of the ship. This is ‘(noted” by the photoelectric cell. The mechanism controlling the course of the torpedo automatically changes so as to direct the torpedo upwardly against the bottom. At the same time the solenoid is energized to explode the torpedo under the ship. To prevent premature explosions, as when the torpedo may pass under some floating debris, there is included a delay action unit which makes it necessary for the photoelectric cell to be cut off from light for an appreciable period of time before the torpedo will esplode. R. I-I. 0.