INSTALLATION OF WEDGE GASKETS.Apply a heavy coating of sealing compound to both faces of the two gaskets (fig. 9-9, #3), and install them over the bolts (fig. 9-9, #4). Use a generous amount of sealing compound at the overlap to seal The opening under the small end.

TIGHTENING TANK BOTTOM.- Work from the small end of the plates and remove all of the catch nuts. Install a rubber gasket, a steel recessed washer, and a nut on each of the bolts. This applies to all of the bolts in the tank bottom with the exception of those in the outer circumference (chime) of the tank bottom,

Figure 9-9.-Method of installing the wedge gaskets at the installation of the last bottom plate

Figure 9-10.-Applytng sealing compound to the bottom chimes of the staves.

which secures the side staves. Tighten all of the bolts in the tank bottom, starting at the small end of the plates.

SEALING SEAMS.- Sweep the bottom clean after tightening the bolts. With the bottom dry, apply a sealing compound to all of the bottom seams (fig. 9-10).

Side Staves

This is a single ring tank Place all of the center support ladder components and the manhole dome on the bottom just before installing the last stave. This is to prevent them from having to be lifted over the top of the staves later. The top and the bottom flanged edges of the staves are called chimes, and the side edges are called vertical seams. The staves have a single row of bolt holes in each seam.

LAYOUT OF STAVES.- There are five special and nine plain staves in the ring. Place the staves with the opening and pipeline connections in the proper position, then lay out the remaining staves around the perimeter of the bottom. Place the staves with the chimes side down for convenience in preparing them for assembly. The staves are laid out so each straddles a radial seam of the bottom.

Staves have an offset at the top and the bottom. The top is determined by looking at the stave in a

Figure 9-11.-Stave chimes bent.

vertical position from the outside. In proper position, offsets are at the lower left and upper left comer.

DRESSING STAVES.- The end of the chime at the offset and the plain section, top and bottom, must be slightly bent for ease in installation. The end of the chimes at the offsets (fig. 9-11) must be bent inward (towards each other). The end of the plain chimes is bent outward (away from each other). The bends are made with a few sharp blows from a hammer.

Along the right seam of each stave, as it will be put in place with the chimes out, place a strip gasket on the outside at the row of bolt holes. The gasket material comes in rolls and is cut to proper length for each stave. Cut the gasket material so that it covers and projects one bolt hole past the top and the bottom chimes.

Insert 1/2-by 1 1/4-inch bolts through the stave joint channel, the stave, and the gasket, in that order. Omit one bolt about 10 inches from the bottom of the stave and other bolts at about 2-foot intervals, so the driftpins can be inserted to align the staves with one another before bolting them together.

PREPARING OUTER EDGE OF TANK BOTTOM.- AS no channels are used with the bolts inserted through the chime (outer edge) of the bottom, it must be raised to provide clearance to insert and tighten the bolts following installation of the staves.

Raise the chime and block it up with short lengths of 3- by 3- or 4- by 4-inch timbers at equally spaced intervals around the perimeter of the bottom. Set the blocking about 16 inches from the outer edge.

Install the strip gasket to coverall of the bolt holes. When one roll of gasket material is used up and a new one is started, the overlap should extend over two bolt holes. Apply putty at each end of the overlap. Insert a wedge gasket underneath the gasket at the laps formed by the bottom plates.

Insert 1/2- by 1-inch bolts through all of the bolt holes in the bottom and the gasket, in that order, except in the lap seams of the bottom. Insert 1/2-by 1 1/2-inch bolts in each lap seam.

Omit the rubber gaskets and steel recessed washers on all of the chime bolts.

FIRST STAVE.-The first stave (fig. 9-12, #1), installed on the bottom, must be the one fitted with a pipe coupling of the same size as the tank supply pipe.

Place the stave over the proper bolts, so the stave straddles a radial seam in the bottom. As a result, each subsequent stave will straddle a radial seam. Install four equally spaced catch nuts to hold the stave in position. Run the nuts down by hand to fasten the stave loosely. The nuts are not tightened until the last stave in the ring is in place.

Two special gaskets are needed. The wedge gasket fills the space by the lap offset at the vertical seam, and a radii gasket is installed underneath the gasket at the bottom and the top chimes of the stave. Radii

Figure 9-12.-Installing first stave.

gaskets must be placed between the chimes and the rubber gasket material at the seams, the top, and the bottom of all of the side sheets to ensure a leakproof connection.

SECOND STAVE.- Install the staves in a counterclockwise direction around the bottom. To assist in the installation of this stave, push two or three bolts flush with the gasket in the chime of the bottom to the right of the first stave. Install the rubber gaskets and steel recessed washers on all of the vertical seam bolts.

Set the stave in position with the left seam outside the right seam of the first stave. Use driftpins in the open bolt holes in the stave to align the holes in the stave. Install the nuts only at every sixth or tenth bolt in the row. As the remaining staves are installed, check carefully the position and the tightness of all the radii, the strip, and the wedge gaskets.

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