Air Holder No. 1.
The beginner will notice in Fig. 10 that this air holder is so constructed that it gets its air pressure direct from the head of water, and also that this pressure can be varied by making the connecting piece of pipe longer or shorter, as may be desired. Of course, the pressure will vary slightly as the water descends into the air chamber, but not enough to make it objectionable, as it will be the helper's duty to watch the water line and renew pumping as often as the water falls below a certain point.
To make this holder, a tank, a, Fig. 10, 12 inches high and 18 inches in diameter, should be constructed of galvanized sheet iron. On this tank double seam a flat bottom. The top must be raised slightly, as shown, to give it strength. This can be done with the raising hammer, or it can be done by making the circle for the top ¾ inch larger than the bottom, then making a cut to the center. It can then be drawn together and riveted in any desired pitch. A hole must be punched in the center of this top large enough to receive a 1-inch galvanized pipe, b. Six inches apart and 2 inches from the edge punch two holes, c and d, large enough to receive pieces of ⅜-inch galvanized pipe. This top should then be fitted and placed on the body of the tank.
Fig. 10.—Air Holder No. 1.
Take a piece of 1-inch galvanized pipe, e, sufficiently long to touch the bottom and projecting 1 inch out of the top of the tank, cut a thread on the projecting end and drill the other end full of ¼-inch holes, f, to the hight of 1 inch, to allow the water to flow freely. This pipe rests on the bottom of the lower tank and carries the weight of the upper tank. Solder this pipe in place. Then take two ⅜-inch nipples, 1 inch long, and solder them into their places, and on these nipples screw two ⅜-inch hose end gas cocks, c and d. One of these cocks is for the purpose of connecting to the air pump, and the other to the mixing cock. As close as possible to the bottom of the tank solder in a ½-inch coupling, g. Into this coupling screw a plug. This is for the purpose of draining the tank when out of use.
Now make another tank, h, 19 inches in diameter and 11 inches deep, the top to be left open and wired with a heavy wire. Double seam a flat bottom on this tank. Directly in the center of this bottom punch a hole large enough to receive a 1-inch coupling. Then cut a 1-inch coupling in half and solder it into this hole, putting the thread side down and leaving it as near flush with the outside of the tank as possible, so that if it is desired to move the air holder to and from a job it can be taken apart and the lower tank nested in the upper tank, making a compact bundle and reducing the danger of damage by careless handling.
To connect these tanks, all that is required is a piece of 1-inch iron pipe, h, 12 inches long, with a coupling on one end. To operate this air holder, close the two air cocks on the lower, or air, tank; then fill the upper tank nearly full of water, taking care not to put too much in it, or it will overflow the lower tank and get into the tubes, and if this happens the tubes will have to be removed and hung up to dry, or drops of water will be blown into the blow pipe and extinguish the flame. It is then ready for use. The air in the air chamber is compressed by the weight of the water in the upper tank, and if the water line is at the same hight as the acid line in the hydrogen gas generator the pressure of air must be the same as the pressure of gas. As air is used the water descends through the pipe and will gradually fill the lower chamber. It can then be forced back into the water chamber by attaching the air pump to the cock h in Fig. 9, or d in Fig. 10, without disturbing the gas or in any way interfering with the operator. To connect with the cock h in Fig. 9 it is only necessary to disconnect one line of hose and connect the pump; then close the other cock and work the pump until air bubbles up in the upper tank; then shut the cock, remove the pump and connect the hose to the gasoline can, open the cocks and the apparatus is ready for use.