Page 420 - Centrifugal Pumps 2E

384 Centrifugal Pumps: Design and Application

or outside diameter of the stuffing box. This is an industry standard for
refinery service. In addition, the gland plate at the stuffing box must
completely confine the static seal.
There are three basic gland plate constructions, as shown in Figure
17-21.
A plain gland plate is used where seal cooling is provided internally
through the pump stuffing box and where the liquid to be sealed is not
considered to be hazardous to the plant environment and will not crystal-
lize or carbonize at the atmospheric side of the seal.
A flush gland plate is used where internal cooling is not available.
Here, coolant (liquid sealed or liquid from an external source) is directed
to the seal faces where the heat is generated.
A flush and quench gland plate is required on those applications that
need direct cooling, as well as a quench fluid at the atmosphere side of
the seal. The purpose of a quench fluid, which may be a liquid, gas, or

Figure 17-21. Basic gland plate designs.