Plunger packing with wedge seal having extrusion recess

摘要

A seal assembly is disposed in an annular recess in a cylinder chamber between a pump cavity and a pump exterior. The seal assembly includes a main seal and a back-up seal and seals to a pump plunger disposed within the cylinder chamber. The back-up seal includes an extrusion recess extending from a surface of the back-up seal adjacent the main seal along an inner or an outer diameter of the back-up seal. During pumping operations the plunger strokes through the cylinder chamber causing the main seal to extrude into the extrusion recess to form a seal between the plunger and the cylinder chamber.

主权项

1. A seal assembly for use within an annular recess of a cylindrical chamber for receiving a plunger in a pump, the seal assembly comprising:
a main seal having an axis, a forward side, and a rearward side; a back-up seal configured to be in abutment with the rearward side of the main seal, the back-up seal having inner and outer diameter cylindrical surfaces; the back-up seal being of a material harder than a material of the main seal and being expansible in a radial direction that is perpendicular to the axis of the main seal in response to an axially directed force; at least one extrusion recess on a forward side of the back-up seal for receiving an extruded portion of the rearward side of the main seal during a forward stroke of a pump plunger; and wherein the backup seal comprises a rearward wedge ring and a forward wedge ring each of the wedge rings having a cylindrical surface, wherein the rearward wedge ring and the forward wedge ring each have a mating angled surface configured to slide against one another such that the rearward and forward wedge rings can slidingly move in the radial direction to adjust a combined radial width relative to a cylinder chamber during operation of a pump and to receive the extruded portion of the main seal at least partially within the extrusion recess during a forward stroke of a pump plunger.