GB1444397A - Fluid pressure control valve - Google Patents

Abstract

1444397 Dual circuit control valves GIRLING Ltd 24 June 1974 [16 July 1973 26 July 1973] 33821/73 and 35735/73 Heading F2F A dual circuit control valve assembly comprises two valves each having a stem movable in response to inlet pressure to close the valve against a preload supplied by a common means comprising a tension spring responsive to vehicle loading and force transmitting means acting on the stems to transmit the spring force thereto. Fig. 1 shows a valve assembly with two circuit inlets 2, 2A and brake line outlets 3, 3A. Upon pressure build-up in both circuits, pressure acts on the cross-sectional difference between right- and left-hand diameters of the stem 5 of one valve 8, 9, and on the right-hand end of a stem and closure member assembly 17, 19, to eventually overcome the bias of the spring 25 to close the valves. Upon pressure failure in either circuit, the pressure build-up in the other circuit to close its valve is doubled. Fig. 2 shows valves 38 operating as the valve 8 in Fig. 1, whereby if a failure occurs in one circuit a plate 47 is pivoted about the stem of the non-operative valve for movement of the other valve. The valves can act alternatively as pressure reducing valves.