US 8,312,805 B1 · High pressure pump piston

Abstract

A high pressure piston for use within a liner sleeve of a reciprocating pump comprises a dual-durometer elastomeric seal having first and second coaxial seal sections and, in certain embodiments, a circumferential bearing ring. Interactions of the seal components, including seal elastomers, result in stress redistribution within the seal which maintains sealing preload, with corresponding improved extrusion resistance and seal durability. When a bearing ring is present, a pump's pressure stroke causes at least a portion of the bearing ring to elastically expand radially to narrow or close the extrusion gap, thus tending to block elastomer extrusion by establishing sliding contact between the bearing ring's external surface and the liner. On the pump's return stroke the slightly wider extrusion gap allows cooling water directed generally toward the proximal flange of the piston hub to better cleanse, as well as cool, the liner wall.

Claims35

Dependent claims

A piston hub and seal assembly having a longitudinal axis, said piston hub and seal assembly comprising:

a piston hub substantially symmetrical about said longitudinal axis, said piston hub having at least one circumferential seal retention area;
and
an elastomeric seal cast-in-place in at least one said circumferential seal retention area, each said elastomeric seal being substantially symmetrical about said longitudinal axis and comprising:
a first seal section having a cylindrical external surface portion adjacent to a frusto-conical external surface portion, said first seal section comprising a first polyurethane;
and
a second seal section, at least a portion of said second seal section lying radially between one said circumferential seal retention area and at least a portion of said first seal section, said second seal section contacting said first seal section along a substantially non-planar intra-seal interface, and said second seal section comprising a second polyurethane having a lower modulus than said first polyurethane;
wherein said first seal section frusto-conical external surface portion is angled outwardly about 3 degrees to about 7 degrees with respect to said adjacent first seal section cylindrical external surface portion;
and
wherein said intra-seal interface comprises a cylindrical portion substantially coaxial with said first seal section cylindrical external surface portion.

6 more elements

A piston hub and seal assembly having a longitudinal axis, said piston hub and seal assembly comprising:

a piston hub substantially symmetrical about said longitudinal axis, said piston hub having at least one circumferential seal retention area;
and
an elastomeric seal cast-in-place in at least one said circumferential seal retention area, each said elastomeric seal being substantially symmetrical about said longitudinal axis and comprising:
a first seal section having a cylindrical external surface portion adjacent to a frusto-conical external surface portion, said first seal section comprising a first polyurethane;
a second seal section, at least a portion of said second seal section lying radially between one said circumferential seal retention area and at least a portion of said first seal section, said second seal section contacting said first seal section along a substantially non-planar intra-seal interface, and said second seal section comprising a second polyurethane having a lower modulus than said first polyurethane;
and
a circumferential bearing ring partially embedded coaxially in said first seal section, said circumferential bearing ring having a cylindrical external surface portion;
wherein said first seal section frusto-conical external surface portion is angled outwardly about 3 degrees to about 7 degrees with respect to said adjacent first seal section cylindrical external surface portion;
and
wherein said intra-seal interface comprises a frusto-conical portion substantially coaxial with said first seal section cylindrical external surface portion.

7 more elements

Dependencies are inferred from the claim text.

High pressure pump piston

Life of this patent

High pressure pump piston

Life of this patent

Abstract

Claims35