Dual sealing valve assembly

Abstract

A valve assembly is disclosed having a valve body with dual valve seats and movable valve member located in the valve body having dual sealing surfaces to bear against the two value seats. One of the valve seats has a sharp-edged configuration which is contacted by a generally frusto-conical sealing surface on a movable primary valve member to crush or break any foreign material in the fluid flow stream. The conical sealing surface and the sharp-edged valve seat also act as a seal to block the fluid flow passageway. A secondary valve member is attached to the primary valve member and has a second sealing surface configured to engage the second valve seat of the valve body. The second valve seat and the second sealing surface may be annular and each have a partially, spherical, cross-sectional configuration. The secondary valve member is connected to the primary valve member such that they may move relatively to each other along their axis of movement. The primary valve member may also be skewed relative to its axis of movement, caused by any foreign particles between the sharp-edged valve seat and the frusto-conical sealing surface without such skewed movement being imparted to the secondary valve member. Thus, even if the primary valve member should be skewed relative to its axis of movement, thereby preventing the first sealing surface from blocking the fluid flow passageway, the sealing surface of the secondary valve member will still contact the second valve seat to block the fluid flow passageway.