Patent ID: 9482211
Filing Date: 2016-11-01
CPC Classification: B24C,F04B,F16J

Claim Text:
1. A seal assembly for sealing a gap between a pump plunger and a high pressure cylinder of a pump, the seal assembly comprising: a first seal ring having a bore through which the plunger extends, a front axial end, and a rear axial end, the rear axial end including a rear surface defining an undercut, the first seal ring positioned to contact both the pump plunger and the high pressure cylinder; a first O-ring positioned on the first seal ring between the front and rear axial ends of the first seal ring to selectively in the presence of fluid pressure forms a first seal between the first seal ring and the high pressure cylinder; a second seal ring having a bore through which the plunger extends, a front axial end, and a rear axial end, a portion of the front axial end extending into the undercut defined by the rear surface of the first seal ring such that axial pressure exerted on the first seal ring in a direction toward the second seal ring deflects the front axial end of the second seal ring radially inwardly to facilitate sealing engagement with the plunger, the second seal ring positioned to contact both the pump plunger and the high pressure cylinder; and a second O-ring positioned on the second seal ring between the front and rear axial ends of the second seal ring to selectively in the presence of fluid pressure forms a second seal between the second seal ring and the high pressure cylinder, wherein the high pressure fluid transmits a pressing force from the first seal ring toward the second seal ring and the second seal is axially spaced apart from the first seal; wherein the undercut of the first seal ring is defined by a first portion of the rear surface that extends substantially normal to the bore, a second portion of the rear surface that extends substantially normal to the bore and that is offset axially from the first portion, and a third portion of the rear surface that extends oblique to the first portion, the second portion, and the bore; wherein the portion of the front axial end of the second seal ring that extends into the undercut is defined by a surface having a first portion abutting and corresponding in length to the first portion of the rear surface of the first seal ring, and a second portion abutting and corresponding in length to the third portion of the rear surface of the first seal ring.