Page:Popular Science Monthly Volume 88.djvu/657

 The Home Workbench

���Making an Acetylene Gas Generator

THE gas generator used by the United States Life Saving Corps and also by the Volunteer Life Saving Corps for their searchlights on beach-wasfons is not difficult to construct, in diameter is used,

��Carbide about V^

��in.

��per pound, home three

��and costs, retail, 10 cents Fifteen pounds will light a hours each evening for one month, at a cost of $1.50. For each pound of carbide a gallon of water is used. Hence to make a 15-pound carbide generator, a 15-gal- lon tank must be used. (Jnly galvanized iron should be used, as it corrodes the least of any metal.

After deciding upon the size (say 15 pounds), take two 15-gallon tanks. Se- lect one which will fit, in- verted, inside of the other, allowing enough space to slide up and down with- out binding (see diagram). Another small tank, half the height, is used to catch the falling carbides. This holds the sediment, prevents it from spreading and simplifies cleaning. Besides, it is the only, tank which cor- rodes. To determine how large to make the hood, use 15 pounds of dry earth as a medium for measuring. Pile it in a cone, the width corresponding to the width of the tank. The height measure- ment gives the depth of the hood. A model of the hood should first be made out of pasteboard to avoid waste or er- ror in cutting. It should fit snugly, in- verted in the gasometer tank. Cut off the point of the hood to allow a 1-in.

���A government gas gen- erator which is easily built by an amateur

��hole for a valve-opening. Lay the mod- el flat on metal and draw around it, cut with shears, roll carefully around a pipe- to get the shape, and solder together. A 1-in. flat washer is used, being soldered into the valve-hole on the inside to act as a guide for the valve-head when it is closed. A A^-in. pipe soldered intj a 1-in. cap for a valve-head and stem can be used, the length of the stem being 2 ins. longer than the gasometer (see diagram). Place the valve in position, solder the hood in the gasometer, and make sure there are no leaks in any of the tanks. If you are not sure of the tight- ness, turn both tanks up- side down and test with water.

In the top of the ometer drill a 2-in. solder in a nipple, screw on a cap with leather washer. This

��gas- hole, and a

is

��used for filling the hood with carbide. A gas-cock is soldered in the side of the gasometer near the top for the gas supply, for the hose, or for the pipe to the gas line. A 1-ft. acety- lene burner gives 100 candle power.

To operate the generator, fill the wa- ter tank with water and the hood with carbide. Close the gas-cock and place the gasometer in the water-tank. Open the gas-cock to let the air out. The gas- ometer will sink very slowly until the valve-stem touches the bottom, thus opening the valve and letting the carbide escape into the inner tank and generate gas. The gas will rai.se the ga.someter three-quarters of the way up, and thus

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