A valve, comprising a housing having means defining an elongate chamber therein and means defining first, second and third ports in said housing which are each in fluid communication with said chamber;
- sleevelike insert means which is disposed in said chamber and includes first and second axially offset insert members, said first insert member having means defining a valve seat thereon which faces generally in a first axial direction and having means for providing fluid communication between said first port and the region within said first insert member on the side of said valve seat remote from said second insert member;
- a closure member supported in said sleevelike insert means for axial movement between first and second positions, movement of said closure member from said first to said second position taking place in said first axial direction, said closure member having sealing surface means thereon which faces in a second axial direction generally opposite said first axial direction and which includes first and second surface portions, said first surface portion sealingly engaging said valve seat when said closure member is in said first position;
- first resilient means for yieldably urging said closure member toward said first position;
- a ram supported in said chamber for axial movement between third and fourth positions, movement of said ram from said third to said fourth position taking place in said first axial direction, said ram having a surface which faces generally in said first axial direction and which is spaced from said closure member when said ram is in said third position, said surface on said ram sealingly engaging said second surface portion on said closure member when said ram has moved from said third position to a fifth position which is located between said third and fourth positions, movement of said ram from said fifth position to said fourth position effecting movement of said closure member from said first to said second position against the urging of said first resilient means;
- second resilient means for yieldably urging said ram toward said third position;
- and means defining first and second passageways which each provide fluid communication between opposite sides of said closure member, fluid flow through said first passageway being obstructed when said first surface portion on said closure member is sealingly engaging said valve seat on said first insert member, and fluid flow through said second passageway being obstructed when said surface on said ram is sealingly engaging said second surface portion on said closure member;
- and wherein said second insert member includes means defining third and fourth passageways therein which respectively communicate with said first and second passageways and which each communicate with a respective one of said second and third ports.