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FIGURE 1 ***Author: Replacement caption was not provided***

0.003 in per inch (0.002 to 0.003 mm per millimeter) of the shaft diameter within a solid stainless steel (typically 12 percent chrome) stationary bushing installed in the pump casing end cover. Grooved serrations are applied to the hardened stainless steel rotating surface (usually a shaft sleeve) or to the stationary bushing or to both rotating and stationary surfaces to effect a high throttling action or stuffing box leakage reduction.

The serrations create a more effective pressure breakdown than a smooth axial surface and enable increased running clearances to let foreign particles, such as grit, pass through or flush out in the grooves. The increased clearances also enable more tolerance for any displacement between rotating and stationary components that might result from assembly misalignment or from distortions induced by transient temperatures. The grooved running surface area at clearances is greatly reduced relative to that of a smooth axial surface, and therefore possible metal surface contact between rotating and stationary parts is reduced during transient operations.

Seal leakage could be reduced by decreasing the running clearance in the injection seal, but the smaller clearance would limit the capability of the serrated seal to conform to radial shaft movement. Reduced clearances in any injection seal design may lead to problems with thermal distortions caused by a loss of available cool injection water and may also increase galling by particles trapped in the seal running fits.

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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