Patent ID: 6959930

Claim:
An oil scraper ring/gas seat ring assembly for disposition in a groove formed in a packing cup which is adapted for stationary mounting over and around a reciprocally mounted piston rod of a gas compressor, said assembly comprising a first annular oil scraper ring for mounting in compression around and against the rod in a first side portion of the groove for scraping oil from the rod as the rod moves in one direction; an annular center oil scraper ring for mounting in compression around and against the rod in a central portion of the groove adjacent said first ring for scraping oil from the rod missed by said first ring as the rod moves in said one direction, said center ring having a diagonally tapered outer peripheral surface portion forming a wedge shaped slot in combination with an adjacent side of said first ring; an annular gas seal ring for mounting in compression around and against the rod in a second side portion of the groove adjacent said center ring for preventing a gas from leaking between the rod and a bore of said seal ring; and an annular side loading element disposed in compression in said slot and bearing against said tapered surface portion and the adjacent side of said first ring for driving said first ring and said center ring axially apart in the groove to form a thermal expansion gap between them for axial expansion of said rings as their temperature increases, for providing a gas tight seal between opposing sides of said center ring and said seal ring and for driving said seal ring against an adjacent side of said groove to prevent a gas from leaking between opposing sides of said seal ring and the groove.