Pilot valve

Claim 1

Pilot valve, comprising a valve body having a cylindrical piston chamber opening thereinto from one of its ends and having a cylindrical passage opening thereinto from the other of its ends, said chamber and passage being coaxially aligned, a cylindrical shaft passage extending coaxially between said chamber and said passage through said valve body, a ring member having one of its ends concentrically disposed around said other end of said valve body and sealingly connected thereto, said ring member having an inwardly projecting annular formation therearound one side of which is engaged with said other end of said valve body and the other side of which forms a valve seat, said other end of said vaove body having an annular inward portion aligned with said valve seat and forming a continuation thereof, a cylindrical valve shaft sealingly but slidably disposed through said shaft passage and extending into said chamber at one end and into said passage at the other end and fixed to a piston sealingly but slidably disposed in said chamber at its said one end and to a valve at its said other end, said valve being sealingly seatable against said valve seat and being moved to seat thereagainst by movement of said shaft in one axial direction and being moved away from said valve seat by movement of said shaft in the other axial direction, a first removable closure closing the open end of said chamber, a second removable closure having a fluid flow inlet therethrough closing the other end of said ring member, a first fluid port to said chamber through said valve body at one side of said piston and a second fluid port to said chamber through said valve body at the other side of said piston, and a fluid outlet through said valve body extending from said passage to the exterior of said valve body.