In one type of wickless stove it is necessary to heat the burner so that the kerosene will vaporize when it comes in contact with it (see Figure 15). Such a burner may be heated by pouring a small quantity of gasoline into it. A lighter is then applied to the burner. When the latter is sufficiently heated, the kerosene is turned on. The kerosene then vaporizes as it flows into the hot burner and burns.
In other types of so-called wickless stoves, the burners are equipped with asbestos or other incombustible material. This material becomes saturated with kerosene and carries the fuel to the tip of the burner somewhat as does a cloth wick.
It is especially necessary to keep kerosene burners clean. Bits of carbon collect in them and prevent perfect combustion. This results in "smoke" or soot issuing from the burner. It is well to keep the burners and wicks free from charred material, and to renew the latter when they become short.
Most kerosene stoves are equipped with removable containers for the fuel. These should be kept filled with sufficient kerosene for burning. A wick burner should never be allowed to burn after all the kerosene in the container is exhausted.
GASOLINE STOVES [Footnote 10: See note to the teacher, Footnote 9.]— Since gasoline is a much more readily inflammable fuel than kerosene, it requires a different type of burner and stove. As a usual thing gasoline cannot be burned in kerosene stoves nor kerosene in gasoline stoves. (In the stove shown in Figure 15, however, either fuel may be burned.)
When gasoline is used in a stove, it is necessary to vaporize the gasoline before lighting the burner. This is accomplished in most stoves by letting the gasoline flow into a cup situated underneath the burner, turning off the supply of gasoline, and then applying a match to the cup. By the time the gasoline is burned the burner is heated. Then the stopcock is turned on, a match applied to the burner, and the gasoline vaporizes and burns.
Gasoline burners, like those in which kerosene is burned, should be kept clean. When a mixture of gasoline vapor and air is heated, an explosion may result. It is for this reason that the tank or gasoline container of a stove should never be filled while the burners of the stove are lighted or even hot.
[Illustration: Courtesy of Westinghouse Electric and Manufacturing
Co FIGURE 16.—ELECTRIC RANGE.]
ELECTRIC STOVES. [Footnote 11: See note to the teacher, Footnote 9.]—It was mentioned previously that electricity is not a fuel. Hence electric stoves are not provided with burners. They have heaters which contain coils of wires through which an electric current passes. Electricity is the cleanest source of heat for cooking. But in order to operate an electric stove economically, it is necessary to utilize the current required for a heating element to its greatest extent. For example, if the current is turned on to heat the oven as many foods as possible should be cooked in the oven (see Figure 16).
[Illustration: FIGURE 17.—PRESSURE COOKER.]