Seal assembly

Abstract

A sealing assembly, designed primarily for both very low and high prssure sealing of a rod while either stationary or reciprocating, comprising a first sealing ring having a generally rectangular cross-sectional configuration and including a diagonally depending wiper arm and a second sealing ring having a generally L-shaped cross-sectional configuration. The arm of the rectangular sealing ring seals in the static mode and also serves to wipe fluid off the surface of the reciprocating rod in the dynamic mode. This wiper arm is provided with a sharp wiping edge which in cooperation with the L-shaped sealing ring maintains both a higher loading per unit area and a high rate of pressure rise at the contact with the rod for maximum leakage control at both low pressure and high pressure. The L-shaped sealing ring also restricts and controls the deformation of the wiper arm so as to maintain an optimum contact area between the wiper arm and rod surface thereby minimizing friction and wear therebetween. The rectangular sealing ring is preferably made of a relatively flowable material such as rubber while the L-shaped sealing ring is preferably made of polytetrafluoroethylene to provide good sealing characteristics and low friction at high pressures. In an alternate embodiment, the L-shaped ring may be replaced with a rectangular cross-section ring, thereby enabling the sealing assembly to fit within a small sealing gland.