Pressure regulator

A pressure regulator having an inlet for high pressure gas and an outlet, said regulator comprising a housing defining first and second chambers separated by a movable partition, wherein said movable partition comprises a rigid central portion, passage means for permitting communication between said first chamber and a reference pressure, said housing carrying pivot means for operative engagement with said movable partition as to thereby establish a pivot axis about which said movable partition may rotate, wherein said pivot axis is located as to define an axis for pivotal rotation which is situated eccentrically of a mid-portion of the rigid central portion of said movable partition, the second chamber including a pilot jet facing the partition and closeable thereby at a position on the side of the pivot axis remote from the centroid of the rigid portion of the partition and a vent leading from the second chamber for fluid communication with the outlet of the pressure regulator, the housing further defining a third chamber communicating with the pilot jet and partially defined by a valve member adapted for movement between an open position and a closed position, to respectively allow or deny access from a high pressure supply port to the outlet of the pressure regulator, the high pressure being supplied to the third chamber via an orifice such that while a predetermined back pressure is applied to the outlet the rigid portion of the partition is held in a position to close the pilot jet and the valve member is held in its closed position by the pressure in the third chamber, and that when the back pressure is reduced to below a predetermined value the pilot jet is opened, the pressure in the third chamber reduces, and the valve member moves towards its open position.