Experimental verification of thermoelastic mechanical seal face deflectionby local wear measurements

Mechnnical seals can wear differentially in a ; radial direction across the ir faces when initially flat faces are distorted by fluid pressure and ther mal gradients. In this study, differential wear on carbon graphite seal fac es was determined by comparing local wear measurements that were made with a novel measurement method. A minute scratch was made on the seal face surf ace with a toolmaker's riffler file and then the depth was measured using a vertical interference microscope. A second image of the same scratch was t aken after a wear test was complete to yield a measure of the absolute wear of the face at one location. Because the scratches are small, differential wear across the face can be measured by placing several scratches at diffe rent radial positions. The wear data of this study validate an analytical m odel of thermoelastic seal face deflections. The data also show, that wear rates decrease with test time.