Importance

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Abstract

The present invention is directed to an improved wear compensating stem sealing apparatus. The elements thereof include a unitarily formed or separably formed O-ring separator disposed upon a valve stem. A first, or 'wiper' O-ring is disposed on the stem in a space provided on the O-ring separator. A second (and in some embodiments, a third) O-ring is disposed about the stem in a similar space on the O-ring separator above the level of the first O-ring. The second and/or third O-ring provide a subsequent sealing of the stem from pressurized fluid migrating upwardly upon wear of the first O-ring. The first O-ring may be made of a material which will wear more rapidly and/or wipe more efficiently than the second and/or third O-ring, or provide less radial squeeze, such that the second and/or third O-ring is subjected to increased compressive pressure from the pressurized fluid upon the wearing of the first O-ring.

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First Claim