GB807267A - Improvements in or relating to fluid pressure valves - Google Patents

Abstract

807,267. Fluid-pressure servomotor-control systems. ROLLS-ROYCE Ltd. Feb. 28, 1956 [Feb. 28, 1955], No. 5952/55. Class 135. The flexible metal diaphragms 11, 12 have their centres inter-connected by a rod 13 whilst the space 14 between the diaphragms is open to the inlet of a gas-turbine engine fuel-pump, not shown, via a channel 15, the diaphragm being subjected to opposing fluid pressures on their other sides; extending from the rod is an arm 17 having opposed pairs of ports 19, 20 and 21, 22 aligned with the free end thereof. The spaces 23, 24 between each pair of ports are joined through a conduit 25 and supply fluid at a controlled pressure to the cylinder of a power device, not shown; the spaces 23, 24 are also in communication with the space 14 by way of ports 20, 21, and with the fuel-pump deliverychannel 26 via ports 19, 22. Co-operating with ports 19, 20 is a valve member 27 formed with a pair of opposed frusto-conical elements 28, 29 disposed in the space 23 and located on a rod 30 maintained in contact with the arm 17 by differential pressure; a further pair of frustoconical elements 32, 33 is associated with ports 21, 22, the elements being oppositely disposed with respect to the other elements 25, 29 and located outside of the space 24, the valve rod 34 being held as before in contact with the arm 17. The valve elements each have the same area and the arrangement is such that the force on each valve element due to fluid pressure is opposed by a similar force on the other element which controls a port connected to the same inlet or discharge side of the pump so that the load transmitted to the diaphragms is reduced or eliminated. In a modification, the connections to the pump inlet and delivery ducts may be interchanged and the valve members connected to the operating arm; the valve members are preferably replaced by a single member formed with two pairs of valve elements. Specification 703,619 is referred to.