It will be necessary to leave small holes between the lead seams at intervals for the hooks to pass through. However, these can be burned over at any time, and where the ends of the top should overlap the end of the chamber the lead can be left turned up until the staging is removed, after which it can be turned over and burned. The hooks are made of ⅝ round iron and have a long thread cut on one end, so as to allow for adjustment. The details are shown in Fig. 41. There are also numerous fittings used in connection with these condensing chambers, but they are all easily made and are too simple to take up space here in explanation. Should it be necessary to use nails for any purpose on the inside of the chamber, the heads should be dipped into a pot of melted lead that has not quite set until the adhering ball of lead is about ½ inch in diameter, as shown in Fig. 43. These nails can be driven in place and the lead burned to the sheet lead, which will prevent corrosion.
CHAPTER XII.
SPECIAL HYDROGEN APPARATUS AND BURNER.
The articles on the universal method of lead burning having been completed, I desire to call attention to a new method and a new generator recently patented and put on the market by the Kirkwood & Herr Hydrogen Machine Company, 3129 South State street, Chicago, Ill. It is called the Kirkwood generator and a general view of it is given in Fig. 44. This generator is a radical departure from the old style generator, as used for the purpose of lead burning, inasmuch as it dispenses with the air blast and consequently with the mixing fork and tubes. The air required to reduce the hydrogen gas to a working condition is obtained by absorbing the air at the mouth of the burner.
The new generator differs also in the amount of pressure used on the gas. With the old style generator, previously described, a pressure of 1½ to 2 pounds is used, whereas the Kirkwood generator is used under a pressure varying from 8 to 30 pounds. At the higher pressure the maker claims the best results are obtained. The generator is made in a size that enables the operator to take it to a job on a street car or train, and that while containing the full charge of acid and zinc, as it weighs when charged about 50 pounds. This is a very important advantage over the old style machine.
Construction of the Generator.
The generator is constructed, so to speak, just the reverse of the old style generator, inasmuch as the lower chamber contains the charge of acid, while the zinc is placed in the upper chamber. The generator shown in the sectional view, Fig. 45, is cylindrical in shape, 9 inches in diameter and 30 inches high. A horizontal partition, to which is burned a pipe long enough to reach to a point about 1 inch above the bottom of the acid chamber, is burned into the cylinder at a point a little above the middle of the cylinder, making the acid chamber larger than the gas chamber. This arrangement allows the back pressure of gas to force the acid down into the acid chamber, compressing the air in the acid chamber without permitting any gas to find its way into the acid chamber and thus preventing a waste of gas. In this horizontal partition and over the pendent pipe a number of ¼-inch holes are drilled or punched. This enables the acid to pass freely into the gas chamber, and prevents any small particles of zinc from falling into the acid chamber, which would generate gas in the chamber. Connected to the top of this acid chamber is a small pipe which runs up through the gas chamber and terminates above it, as shown. This pipe has an air inlet valve, or small hose end gas cock, connected into the side of the pipe, to which the hose from the force pump is attached when supplying air to the acid chamber to force from the acid chamber to the gas chamber in order to start the generation of gas. A safety or blow off valve is also attached to this pipe at the top, and is set to an ordinary working pressure of 15 pounds, or to any pressure desired. If gas is being generated faster than is required it gets up a pressure in excess of 15 pounds. Then the safety valve opens and allows the air in the acid chamber to escape until the gas goes down to the desired pressure again. This obviously allows a portion of the acid to return to the acid chamber, and later, as the acid becomes weaker, the air in this chamber will have to be renewed by the admission of a little more air.
| Fig. 44.—General View. | Fig. 45.—Sectional View. |
| The Kirkwood Lead Burning Machine. | |
Fig. 46.—The Kirkwood Lead Burner.