The acetylene gas jets are lighted ordinarily with a match or taper but electric igniters are often used for that purpose. Electric lighters for acetylene lamps are practically the same as those used with ordinary gas lamps but they must be adapted to the type of burner on which they are used. Electric igniters that are intended to be used with lamps placed in inaccessible places are different in construction from those within reach. In Figs. 214 and 215 are illustrated two forms of igniters that are intended to be used on bracket or pendent lamps. They differ in mechanical construction to suit two different conditions. Fig. 214 is an igniter in which is also included the gas-cock. The gas is lighted by pulling a cord or chain attached to the lever L. The movement of this lever turns on the gas and at the same time brings the piece C in contact with the wire A to complete an electric circuit. As the contact between these two pieces is broken, a spark is formed that ignites the gas escaping from the burner at B. On releasing the lever a spring returns the piece C to its original position. The light is extinguished by a second pull of the lever.

Fig. 215 illustrates a style of igniter which may be attached to an ordinary gas-cock. It is attached to the stem of the burner by a clamp D. The gas is turned on by the usual gas-cock and by pulling the chain at the left the jet is lighted. In pulling the chain the arm A is raised and carries with it the arm B. When the arms A and B touch, an electric circuit is formed with a battery and spark coil. When the desired position of the arms is reached, the points separate to form an electric flash which lights the gas.

Fig. 216 illustrates in A the method of installing electric igniters like those described. A battery B and a spark coil S are joined in circuit as shown. The gas pipe acts as one of the wires of the circuit. A battery of four dry cells is commonly used for the purpose. The spark coil is a simple coil of wire wound on a heavy iron core, which serves to intensify the spark when the circuit is broken. In using the igniter, it is only necessary to see that the cells are joined in series with the coil and attached to the insulated part of the igniter. As already explained the action of the igniter is to close the circuit and immediately break the contact at a point where the spark will ignite the gas. On being released the igniter returns to its original position.

In the fixture shown at C is an igniter such as is used in places that cannot be conveniently reached. To light the jet, the circuit is completed by turning the switch at W. As soon as the gas is lighted the switch is again turned to break the igniter-circuit. In this device the current passes through a magnet coil in the igniter which acts to open and close the circuit with the same effect as in the others.

Fig. 216. - Diagram of electric igniters attached to gas burners.

Acetylene Stoves

Stoves in which acetylene is used as a fuel are quite similar in construction to those which burn coal gas. The principle of operation is that of mixing the acetylene with air in proper proportion so as to produce complete combustion when burned.