Alcohol, Acetylene, and Canned Heat 42. Alcohol Stoves. Alcohol stoves are made only in small sizes for light housekeeping. There are three general types of these—those which burn with a wick, those which generate gas, and those which permit the alcohol to burn off of the top surface of the container. Alcohol does not produce much smoke in burning, even when no provision is made for mixing air with it. The ordinary alcohol lamp, having a wick, may be used as a heating stove. Stoves with wicks draw the alcohol up by capillary attraction to the point of ignition, and the metal jacket about the wick prevents the fire burning back into the bowl containing the alcohol. The char from the top of the wick must be brushed off from time to time. No other care is needed for these stoves or lamps. Some of them are provided with devices for checking the burning of the alcohol in order to regulate the heat. This is desirable since a small flame of alcohol produces much heat. Extinguish the fire by covering the wick with a metal cup. 43. Vapor Stoves. Alcohol vapor stoves which generate gas hold the alcohol in a tank slightly raised above the level of the burner. A pipe leads from this to the burner, where a small stream of alcohol is permitted to enter when the valve is open. When starting these stoves, the valve is first opened and enough alcohol allowed to flow out to fill a cup which is below This heats the burner enough to vaporize the alcohol. When the burner is heated, open the valve and ignite the gas. If all the alcohol is not vaporized, the burner has not been heated hot enough. Close the valve until all the alcohol in the cup is burnt. 44. Wickless Stoves. Wickless alcohol stoves are used commonly on chafing dishes. The burner of one type consists of a metal dish packed with a porous material which is non-inflammable, but a good conductor of liquids by capillary attraction, and the top is covered over by a wire screen. The alcohol is poured into the dish. The packing and screen prevent air from entering the bowl with sufficient rapidity to let the fire burn below the screen so the flame stays above it, burning off any alcohol which is conducted to the surface. The only possible way to control these stoves is by a device which can cut off air. One of these is a plate-like device with a handle. This fits over the stove and only that portion of the top burns which is exposed to air through the hole in the plate. Making the hole larger or smaller makes the burning surface larger or smaller. To extinguish the fire, cover the entire top with a solid plate to cut off all air. 45. Canned Heat. Canned heat is alcohol combined with other substances into a cake about the consistency of hard soap. The cover to the can is used to extinguish the fire. It should not be fitted into the top of the can until the flame has been extinguished for two or three seconds. Then 46. Acetylene Gas Stoves. By adjustment of the amount of air that enters the burner, acetylene may be burnt in a gas stove. Usually a cap is placed over the air hole while the gas is being ignited. This is removed as soon as the gas is lighted, so that it will burn with a blue flame. The use of the cap prevents burning back. It is best, however, to use stoves especially designed for burning acetylene. |