Gland Plate Construction

An essential component of any seal installation is the gland plate. The purpose of this part is to hold either the mating ring assembly or the seal head assembly, depending on whether the seal head is rotating with the shaft or stationary to the pump casing. It is also a pressure-containing component of the installation. The alignment of one of the sealing surfaces, particularly the mating ring used with a rotating seal assembly and a gland plate bushing, is dependent on the fit of the gland plate to the pump. To ensure the proper installation, the API specification requires a register fit with the inside or outside diameter of the seal chamber. The static seal on the face of the seal chamber must be completely confined. Three basic gland plate constructions are shown in Figure 34:

• 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 hazardous to the plant environment and will not crystallize 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 seal 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 atmospheric side of the seal. The purpose of the quench fluid, which may be a liquid, gas, or steam, is to prevent the buildup of any carbonized or crystallized material 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. This gland plate can also be used for flush, vent, and drain where seal leakage needs to be controlled. Flammable vapors leaking from the seal can be vented to a flare and burned off, while nonflammable liquid leakage can be directed to a safe sump.

Figure 35 illustrates some restrictive devices used in the gland plate when quench or vent-and-drain connections are used. These bushings can be pressed in place, as in Figure 35a, or allowed to float as in Figures 35b, c, and d. Floating bushings enable closer running clearances with the shaft because such bushings are not restricted at their outside diameter. The bushing shown in Figure 35d is also split to enable the thermal expansion of the shaft. This restrictive bushing is preferred on refinery applications. Small packing rings can also be used for a seal quench, as shown in Figure 35e.

Survival Treasure

Survival Treasure

This is a collection of 3 guides all about survival. Within this collection you find the following titles: Outdoor Survival Skills, Survival Basics and The Wilderness Survival Guide.

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