Fig. 36.—Burning in the Tee Joint.
If the tank is over 18 inches high the lead must be fastened to the sides with bullseyes. These are made by countersinking places in the sides of the tank. The lead is then dressed into these holes and it is held in place with large headed brass screws, which are covered by burning over the heads. Lead for the purpose is taken from lead strips. The building up process is resorted to in covering these screw heads.
The lead should be arranged so as to avoid corner seams as much as possible, as it is quite a difficult job to get the proper thickness of lead in such seams. No rule can be given for cutting lead to fit a tank, as tanks are of such a variety of sizes and shapes, and the lead is of so many widths, that the mechanic must study how to cut the stock without waste and have as few seams as possible.
CHAPTER XI.
ACID CHAMBER WORK.
It is not my intention to give an elaborate description of how acids are made or to attempt to describe all of the different fittings employed in that work, because while all plants are similar in construction no two are alike. For that reason I will confine myself to the methods employed in handling lead in large quantities, as the lead used in this work ranges in weight from 18 to 24 pounds to the foot and is therefore very heavy to handle. These chambers are known as condensing chambers, and their use is to catch and condense a mixture of sulphur and steam which is blown into them through a large lead pipe. For that reason they are usually built out of doors, and sometimes have a sort of temporary roof built over them. Consequently in repairing they are easily gotten at, which, by the way, is seldom necessary.
Fig. 37.—Method of Framing Chamber.
To begin with, the sheet lead should be purchased of such a width as to make as few seams as possible. The bottom of the chamber for this lead to lie upon should be made of 2-inch cypress plank, the same to be tongued and grooved as for floors, and should be planed down, if necessary, so that it will present a perfectly smooth surface for the lead to rest upon, for if there are any uneven spots that is where the lead will eventually crack. The frame work for the sides should also be put in place before the lead work is started, or at least enough of it to prevent dirt and other stuff from bothering the burner. One end of the chamber, however, should be left open, so as to enable the workmen to bring in the lead or other material. The sides should not be closed up, but should be framed, as shown in Fig. 37, so as to allow the lead to be securely fastened to the frame work, which should be made of heavy stock, depending, of course, upon the depth and size of chamber, as they are in all sizes, from 10 feet to 60 feet long and longer.
After seeing that this part of the work is all right, begin to place the bottom in position. This lead should be cut large enough to allow of its being turned up about 2 inches all around for tight tanks. The sides are not burned to the bottoms of some chambers, but the bottom lead is turned up different hights, depending upon how deep it is required to carry the acid in the chamber, which is from 4 to 10 inches or deeper. The studding should be notched out to allow the turned up lead to face with the face of the studding, otherwise there would be a bend in the side lead where it overlaps the sides of the bottom. The flat seams in the bottom should be butted together, so as to give a perfectly smooth surface, which will allow all the acid to be drawn off.