Abstract: A relief valve (10) incorporating a poppet assembly (14) having a metallic sealing disc (46) in engagement with an annular valve seat (34). The disc is acted on by a ball (44) received within a recess formed in the end of the poppet stem (36). The disc and the ball are retained in free-floating relationship with the stem by means of a cylindrical retainer (40), which allows the ball to center itself over the disc and valve seat and thus effectively apply the closing force at a point at the center of the disc. The point application of the closing force causes the disc to flex a finite amount, which causes the disc to contact the inner edge only of the annular valve seat, thus approximating an ideal knife-edge engagement between the valve seal and the seat.

Abstract: A pressure relief valve (10) including a valve stem (34) having an elastomeric valve element (36) received in a counterbore (38) formed in one end thereof and engageable with a valve seat (32) formed in the body (12) of the valve. An annular channel (58) is formed in the valve body surrounding the valve seat, and the valve element is recessed below the outer edge of the counterbored end of the valve stem, such that a thin, annular wall section (39) defined by the difference between the diameter of the counterbore and the outer diameter (40) of the valve stem, extends downward into the annular channel when the valve is closed.The outer diameter of the counterbored end of the valve stem is substantially smaller than the inner diameter (22) of the main valve chamber to define an annular fluid escape passage (64) and a lip is formed on the valve stem above the counterbored end to guide the valve stem in the main valve chamber.