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9.24 CHAPTER NINE

Vertical Edge Outlet
Bottom Outlet
FIGURE 9.14 Vacuum leaf mountings.

Outlet Connections. Fixed-leaf filter leaves usually have spigot-type outlet connections
made of castings machined to fit into the sockets of the outlet manifold. Figure 9.15 shows
two types of outlet construction. The central drain hub shown in the figure is used for ro-
tating leaves and is of two-piece construction, clamped to the center of the circular leaf
by bolts. The leaf outlet connection must be of sufficient size to allow full flow of the fil-
trate collected by the leaf at a minimum head loss. As leaf size and loading increase, the
distribution of flow within the leaf and the transition to the outlet connection increase in
importance.

Comparison of DE Filter Systems
If DE filtration has been selected for use in a water treatment system, a selection must be
made between vacuum and pressure filter options. The length of filter run expected from
either type of filter should be determined in pilot testing preceding design evaluation. The
two types of filter systems may be evaluated in regard to costs, including the following
items:

• Capital cost of installation of the complete filter system and ancillary equipment

Section AA Section BB S D

Center Drain
"O" Ring Gasket Flat Gasket 2 Piece Hub
FIGURE 9.15 Outlet connections.