GB821053A - Fluid pressure-reducing mechanism - Google Patents

Abstract

821,053. Valves. DUNLOP RUBBER CO. Ltd. Feb. 7, 1957 [Feb. 28, 1956], No. 6106/56. Class 135. A pressure-reducing valve comprises a pressure chamber 13 connected to a source of fluid pressure through an inlet 14, an operating chamber 9 connected through an outlet 10 to a mechanism to be operated, a piston 3 slidable in the operating chamber, an annular knifeedged valve member 19 controlling a passage leading from the pressure chamber to the operating chamber, the valve member being attached to a metal bellows 17 and seating on a seat 20 formed on the wall 15 separating the two chambers, means interconnecting the piston and valve comprising a piston-rod 24 abutting the valve member and carrying a stem 30 on which the valve member is free to slide, but is urged into abutment with the end of the piston-rod 24 by a light spring 32, a spring 7 acting on the piston in a direction to open the valve member 19 to maintain the valve open until the pressure in the operating chamber reaches a predetermined pressure to move the piston to close the valve and a plurality of angularly equi-spaced axially extending passages 11 in the bore of the operating chamber 9 arranged such that should the pressure in the operating chamber rise above the pressure required to close the valve 19, the further movement of the piston 3 will uncover the ends of the passages to permit the excess pressure to exhaust to atmosphere via the outlet 6. The outer diameter of the valve member 19 is equal to the effective diameter of the bellows 17 so that the loading of the valve is not affected by the pressure in chamber 13. The outlet 10 may be located at the end wall 18 of the housing 1 within the bellows 17, the air passing through passages 12 in the valve member 19 and the passages 11 may be replaced by holes in the wall of the operating chamber leading directly to atmosphere.