Relief valve

In a relief valve comprising a body having an inlet port formed therein, a chamber intersecting said inlet port, a valve seat defined by the intersection of said inlet port with said chamber, a valve poppet assembly disposed within said chamber and movable between a first position in engagement with said valve seat and a second position out of engagement with said valve seat, at least one exhaust port formed through said body leading radially outward from said chamber, a spring biasing said poppet assembly into engagement with said valve seat, said spring being enclosed by said body, and an annular channel formed in said body surrounding said valve seat;

• the improvement wherein said poppet assembly comprises a cylindrical stem member;
• a counterbore formed in an end of said stem member, the diameter of said counterbore being slightly smaller than the diameter of said end to define a thin annular wall section therebetween;
• a resilient valve element received in said counterbore and engageable with said valve seat, the thickness of said valve element being somewhat less than the depth of said counterbore such that the annular wall section extends beyond the outer face of said valve element and into said annular channel when said poppet element is in its first position;
• a radially extending annular lip formed on said stem member and spaced above said end thereof to define a chamber within said valve body above said lip, the outer diameter of said lip being slightly smaller than the inside diameter of said chamber to define a sliding fit therebetween;
• and means for limiting movement of said valve stem in a direction out of engagement with said valve seat, the relationship between the axial location of said lip and said at least one exhaust port being such that at least a portion of the cross-section area of said at least one exhaust port is open to said chamber above said lip when said valve stem is in its maximum position out of engagement with said valve seat.