COMPRESSION PACKING

Engineering Data/FAQs

Utilization of Gasket Spacers

For some time, gasket spacers have been used in conjunction with braided packing rings to enhance performance in a variety of applications. The main purpose in using gasket spacers is to close up the clearances that exist around the inside diameter of the packing set. By cutting the I.D. of the gasket spacers close to the shaft diameter, the spacer can serve as an "excluder", keeping solid particles from progressing through the packing set along with the liquid leakage. In some cases (particularly where the leakage rate is relatively high) a spacer would also act as a throttle bushing, causing the pressure to be reduced on the "outboard" side of the spacer.

Gasket spacers are particularly effective in cases where excessive clearances exist between the I.D. of the stuffing box bottom and the shaft O.D. Excessive clearances may exist because of wear, corrosion, or simply the way a piece of equipment is manufactured. Here, a spacer can also serve to keep the packing from extruding beyond the stuffing box bottom.

In applications involving high stuffing box pressures (particularly reciprocating pumps) gasket spacers can be used to reduce the amount of leakage that occurs through the body of the braid. The spacers (being nearly impermeable) force leakage to the I.D. of the packing set and help eliminate O.D. leakage.

Another advantage of using spacers in reciprocating pumps is that they serve to keep the packing "square". The alternating direction of the shaft, along with the high frictional forces that result from the high pressure, cause the packing to be stressed back and forth continually. In some cases this can actually make the packing "roll over" in the stuffing box. This can eventually cause a premature failure. The rigidity of gasket spacers helps to restrict packing movement.

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