GB994818A - Improvements in or relating to fluid control valves - Google Patents

Abstract

994,818. Hydraulic apparatus. H. TEVES, E. A. TEVES, and M. TAUSEND, [trading as ALFRED TEVES MASCHINEN-UND ARMATURENFABRIK KOMM. GES]. March 27, 1963 [April 4, 1962], No. 12106/63. Heading FIP. In a fluid-pressure control system a pump, not shown, connected to a pipe 17 charges via a valve 1 and a check valve 22 a pressure accumulator 24 connected to a load system having a multi-way valve 25, the valve 1 comprises a casing having a piston valve 2 slidable therein and defining therewith a first chamber 5 connected by a pipe 26 to the accumulator 24 and a second chamber 6 containing a compression spring 7, the arrangement being such that the accumulator pressure is operative to displace the piston valve to the left whereby the pump supply is by-passed through a pipe 20 leading to a tank. A branch pipe 18 connected to the supply pipe 17 communicates the pump pressure to a passage 12 to act on the end face 19 of a plunger 11 integral with the piston valve 2, and the accumulator pressure is communicated to the chamber 5 through the pipe 26, a check valve 27 and a restriction 8 to act on the face 28 of the piston 2. As the charging proceeds the pressure in the chamber 5 and the passage 12 rises and because of the difference in area of the faces 19 and 28 the piston is displaced to the left until the groove 4 is uncovered whereby the pressure in the chamber 12 collapses and the piston valve snaps fully open by-passing the pump supply. When the pressure in the accumulator 24 falls a piston 29 having a tappet 30 is urged by an adjustable spring 31 to open the check valve 27 thereby allowing the piston valve 2 to return to the position shown. In a modification the pressure is communicated to the chamber 12 through passages drilled in the piston valve 2. In another embodiment the check valve 27 is a shouldered plunger having an axial bore for a poppet valve which is opened by the tappet.