Valve

Claim 1

A control valve comprising: a cylindrical hollow housing having a longitudinal axis; a first chamber formed within said housing; a first valve seat associated with said first chamber; a source of fluid under pressure coupled to said first chamber; a second chamber formed within said housing spaced from said first chamber, said first valve seat being disposed between said first and second chambers; a low-pressure reservoir coupled to said second chamber; a longitudinally movable member disposed coaxially of said longitudinal axis within said housing including a first valve member disposed on the outer surface thereof adjacent said first chamber and a first longitudinal bore through said movable member having a given diameter and disposed coaxially of said longitudinal axis; a first spring engaging said movable member to hold said first valve member against said first valve seat; a longitudinal actuator for said movable member disposed coaxially of said longitudinal axis within said housing and longitudinally spaced from said movable member, said actuator having at least a portion thereof adjacent said second chamber and a second longitudinal bore through said actuator having said given diameter and disposed coaxially of said longitudinal axis; a utilization means coupled to said second bore and being in communication with said reservoir through said second chamber when said valve member is seated on said valve seat; first means spaced from said first valve seat and disposed between said first and second chambers to provide communication between said first chamber and said utilization means through at least said second bore when said first valve member moves off said first valve seat; and second means carried by said actuator to close the communication between said reservoir and said utilization means prior to moving said first valve member off said first valve seat when said actuator is moved axially toward said movable member.