Automatic pressure-control valve, especially for a pressurized-gas supply installation

Claim 1

A pressure-control comprising: a valve body having two housing parts connected together and defining an elongated valve chamber, said body being formed with at least two longitudinally spaced-apart ports communicating with said chamber; a poppet-type valve member linearly displaceable in said chamber longitudinally thereof and having a doubly-conical valve head defining a pair of oppositely converging sealing surfaces; a seating ring of deformable polytetrafluorethylene clamped in said body between said housing parts and engageable with a selected one of said sealing surfaces upon displacement of said valve member and positioned interchangeably with a seating ring engageable with the other valve surface thereof; a spring received in said body and acting upon said valve member to bias the latter in one linear direction against a fluidpressure differential applied to said head, said valve forming a pressure-buildup controller upon insertion of one of said rings into said body and a pressure-drop controller upon introduction of the other oF said rings into said body; and a spacer sleeve in said body and bearing axially upon said ring, said sleeve being axially engaged by one of said housing parts and urging said ring annularly against the other housing part; One of said housing parts including a casing receiving said spring, a disk threaded into said casing and forming a seat for said spring, a partition in said one of said parts separating said casing from said chamber and formed with a throughgoing bore slidably receiving an end of said valve member remote from said head, at least one vent passage formed in said partition and communication between the interior of said casing and a space around said valve member, and an axially extensible and contractable bellows anchored at one end to said head and at the other end to said partition and enclosing said vent passage.