Air line pressure regulator

Claim 1

A fluid pressure regulator comprising a. a housing having an inlet at one side and an outlet at the other, the outlet terminating within the housing in a downwardly facing annular seat, an annular upward guide wall in the housing below and aligned with said seat, the housing also containing a regulator spring and a pressure diaphragm communicating with the outlet, the diaphragm having a central vent port; b. a valve member having an upwardly facing annular sealing surface adapted to seal against said seat, the valve member having a downward piston extending into the guide in sealing relation, the valve member having an axial bore extending from the top to the bottom thereof and having three connected portions, an upper, wider portion and a lower, narrower portion, and a tapering portion intermediate the two, all portions being circular; c. a valve stem extending through the bore and upward therefrom into the outlet passage, the lower portion of the stem being of smaller diameter than the lower portion of the bore and the second portion of the stem, immediately above the lower portion, fitting snugly into the upper portion of the bore and having at least one flat side, the upper end of the stem normally blocking the vent port being urged downward by the regulator spring, and d. means removably but firmly attaching the stem anD the valve member with the bottom of the upper portion of the stem shouldering on the tapered portion of the bore, the attaching means tightly engaging the bottom of the valve member, whereby downstream pressure communicates through the valve bore between the stem and the valve member to the chamber formed by the piston and guide to substantially balance the forces on the valve member, and the firm attachment of the stem and the valve permits accurate operation of the regulator and proper alignment with the vent port.