Rotoflex, Inc.

Leonid G Zeltser

Arnold Kholodenko

Brian Simmons

A dry-face sealing method for preventing leakage around a rotary shaft uses an annular rigid seal having a smooth sealing surface and an annular resilient seal having a projecting sealing edge aligned coaxially therewith. The annular resilient seal has a breaking elongation of at least about 100 percent of its original length, the resilient seal being stretched at least about 20 percent and less than 40 percent of its breaking elongation in a direction substantially parallel to the smooth sealing surface to align polymeric resilient seal components in a direction parallel with the smooth sealing surface and smooth the sealing surface thereof. The projecting edge, because of its shape and position, functions as a stress concentrator, concentrating the stress hardening effect on the sealing surface of the projecting edge. The method comprises pressing the projecting edge in an axial direction against the smooth sealing surface with a pressure which is sufficient to effect a seal therebetween under operating conditions of the seal but which will not produce sufficient heat of friction to cause significant chemical changes in the projecting edge of the resilient seal. The result is an effective rotary sealing which does not require a liquid for lubrication or radial emission suppression. The smooth sealing surface of the device can be adjusted to change the sealing pressure to accommodate operating conditions, using a moveable, threaded housing made of a material having a high thermal conductivity. This primary seal can be used alone or in combination with a backup dry face stuffing box seal.

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Pleasanton, CA, United States of America

Leonid G Zeltser