A 2,300 psi rotary shaft seal test with 0.015” radial extrusion gap clearance


A pair of 10.49” PN 682-21-303 extra wide type A plastic lined seals was tested for 100 rotating hours at 2,300 psi (15.85 MPa) and 45 rpm (123.6 sfpm) using an ISO 68 viscosity grade lubricant and a nominal radial extrusion gap clearance of 0.015”. The test included 353 rotational start/stop cycles under full pressure. The seals were in excellent condition at the conclusion of testing, despite operating with such a large extrusion gap clearance. The combined hydrodynamic pumping related leak rate for the pair of seals was 0.42 ml/hour.

Antifreeze was circulated through a cooling circuit above the pair of seals and through a small heat exchanger at about 0.9 gpm. The coolant entering the test fixture was about 76°F and the coolant exiting the test fixture was about 82 to 85°F. As a result of this modest amount of circulation, the bulk lubricant temperature between the seals ranged from 100 to 120°F. The region below the rotary seals contained stagnant (i.e. non-circulating) oil.

Because the upper rotary seal was exposed to a circulating coolant during the 2,300 psi test, it has less wear than the lower rotary seal. Both seals are in excellent condition after 100 hours of operation.

 

This is the fixture that was used to perform the 2,300 psi rotary shaft seal test.