Patent ID: 6840520
Filing Date: 2005-01-11
Classification: F16J,F16K,Y10T

Abstract:
1. A valve comprising: a body defining a bore extending along an axis; a plug sized to fit inside the bore and adapted for slidable movement along the bore axis; a seal ring disposed between the plug and the bore, the seal ring being formed of a flexible material to tightly seal between the plug and the bore; a first wiper ring disposed between the plug and bore and positioned axially upstream of the seal ring; a second wiper ring disposed between the plug and the bore and positioned axially downstream of the seal ring; a first back-up ring positioned between the second wiper ring and the seal ring and, a second back-up positioned axaially downstream of the second wiper ring; wherein each of the first and second wiper rings have an outside surface sized to engage the bore and are formed of a wiper ring material sufficiently rigid to scrape foreign material from a surface of the bore as the plug moves yet sufficiently resilient to minimize damage to the bore surface.