Insert the channel assembly through the center bottom plate and gasket.

NOTE: To prevent damage to the gasket, do not use a sharp-edged tool or pipe to force the gasket over the bolts. Use a well-rounded, smooth, mouth tool.

Lay the center bottom plate on the bolt-retaining boards. These boards will prevent movement of the bolts when the bottom plates are installed.

Bottom Plates

The tank bottom consists of 14 tapered, flat steel plates. Thirteen plates are plain, and one is soecial. All of the plates are interchangeable. When the bottom is completely installed, the plate pattern resembles a wheel. The first bottom plate (fig. 9-7, #7) has a bolt channel placed under each radial lap seam with l/2- by 1 l/4-inch bolts (fig. 9-8). A strip gasket is placed along each seam. The seams are identified as right and left, facing the large end.

Starting at the large end of the plate (fig. 9-7), place a bolt channel under the right and left lap seams of the plate. Insert the bolts through all except the end bolt holes in the plate and channel. As the channels are put in place, position the bolt-retaining boards to facilitate installation of the gaskets. Install the gasket along the full length of the right and left lap seams. Allow a l/2-inch bolt hole overlap at each end. NOTE: When there is a break in the gasket material, the ends should overlap two bolt holes and be cut squarely across the second hole. Putty must be

Figure 9-8. - Installation of bottom plates.

applied to each end of the overlap strip to ensure a leakproof joint.

Upon the completion of the assembly, move this plate to the approximate installation position on the tank foundation.

Of the 13 intermediate plates, one is an outlet plate, which is assembled with channels and strip gaskets. The channels are placed under the right lap seams. Follow the same assembly procedures as outlined above. In addition, the outlet plate has a blind flange set assembled on it. The above procedure does not apply to the last bottom plate as no further assemblies are made on it. Keep the last bottom plate separated from all of the other plates until it is installed in the tank bottom.

Cut six one-hole gaskets from the strip gasket material (fig. 9-8, #2). Force a one-hole gasket over and against the head of each flange bolt. Insert the bolts through the bolt holes in the inside flange half from the outside face of the flange with the heads of the bolts fitting into the cutouts provided. Lay bolt-retaining boards on the ground. Position the flange assembly with the bolt head resting on the boards. Slip a gasket over the bolts and force it down against the inside face of flange #7, using a round smooth, mouth tool. Work from the ground face of the plate (fig. 9-7, #7) and push the bolts through the bolt holes of the flanged opening. Place blocking under the bolt and flange assembly to hold it in position. Slip a gasket over the bolts and force it down against the inside face of the plate. Slip the outside flange half over the bolts with the machined face of the flange facing the gasket. Apply the nuts to the bolts. lighten the bolts. Remove the plate from the blocking and lay it on the tank foundation

With the first bottom plate in the approximate installation location on the tank foundation, lay the remaining plates around the tank foundation. Proceed with the installation as follows.

FIRST PLATE. - Place the small end of the plate over the center plate bolts (fig. 9-8, #3). Apply finger-tightened catch nuts to the bolts inside the lap seams. Catch nuts are ordinary nuts applied to the bolts to hold the assembled plates in position.

FIRST INTERMEDIATE PLATE . - Wedge-shaped gaskets must be used wherever three plates are joined together. Before installation of the plate, you should place a wedge gasket (fig. 9-8, #4) over the gasket (fig. 9-7, #3) at the right edge of the first plate #7. Face the small end of the plates. Install