Page 421 - Centrifugal Pumps 2E

Mechanical Seats 385

steam, is to prevent the buildup of any carbonized or crystallized mate-
rial along the shaft. When properly applied, a seal quench can increase
the life of a seal installation by eliminating the loss of seal flexibility due
to hangup.
A flush, vent and drain gland plate is used where seal leakage needs
to be controlled. Flammable vapor from a seal can be vented to a flair
and burned off, while non-flammable liquid leakage can be directed to a
sump.
Figure 17-22 illustrates some common restrictive devices used in the
gland when quench or vent and drain connections are used. These bush-
ings may be pressed in place, as shown in Figure 17-22A, or allowed to
float, as in figures 17-22B, C and D. Floating bushings allow for closer
running fits with the shaft because such bushings are not restricted at
their outside diameter. Floating bushings in Figures 17-22C and D, are

Figure 17-22. Common restrictive devices used with quench or vent-and-drain
gland plate.