Patent GB-607767-A (GB)
Title: Improvements in or relating to flow dividing and equalizing means, and hydraulic systems and controls including the improved flow dividing and equalizing means
IPC: F15B11/22
Filed: 1944-04-04
Abstract: 607,767. Fluid-actuated valves. PESCO PRODUCTS CO. April 4, 1944, No. 6263. Convention date, April 16, 1943. [Classes 69 (ii) and 135] [Also in Groups XXVI and XXXIII] In a hydraulic control system such as, for example, for operating the wing flaps 22, 24, Fig. 1, of an aircraft by a number of double-acting hydraulic motors 68-74 from a single control valve 28, fluid flow dividing and equalizing means shown at 34, 56 and 58 are provided to divide and equalize the flow from supply conduit 35 to conduits 52, 54 and from conduits 52, 54 to conduits 60, 62, 64, 66 and 61, 63, 65, 67 respectively. The two-way flow divider and equalizer 34 shown in Figs. 2-4 comprises a double gear pump structure 92, 94 and 96, 98 operating under the flow of a supply of pressure fluid from conduit 35 to a common inlet 110 for the two pumps. Each pump has a separate outlet port 118, 120 from which the pressure fluid passes to outlets 126, 128 to which are connected the conduits 54, 52 respectively. Valves 134, 136 are provided in chambers 122, 124 which open under the supply pressure or control the flow from each pump to compensate for any differences of pressure arising in the outlet conduits due to different resistances so that the flows are equalized to ensure equal operation of each motor or, in this case, each set of motors. Each of these valves comprises a valve member 140 sliding in a bore 160 against a spring 142 seating it upon a seating ring 138 and a second valve member 148 carried by the valve member 140 controlling a passage through openings 146 therein. The valves 148 and 140 are provided with small clearances in their bores so that the outlet pressure acts in chamber 162 behind these valve members so that any increase tends to close valve member 140 and reduce the flow therethrough. The pressure in chamber 162 of one valve is communicated to the corresponding chamber of the other valve through a passage 158 and annular chamber 132 of each valve and a communicating passage 130, Fig. 3, so that change of pressure on one valve is communicated to the other with a corresponding closing movement to maintain the flows equal. The valves 148 act as check valves which open to allow return flow of the fluid when the operation of the hydraulic motors is reversed. A pressure relief valve 178 is provided in the communicating passage 130 to relieve excessive pressure developed in the system by, for example, heat. The four-way flow dividers and equalizer 56 and 58 function in essentially the same way as the device 34, but each pump comprises a compound pump of three gears which divides the flow into two, so that with a double pump four outlets are provided. An equalizing valve is provided for each outlet in which the outlet pressure acts on the back of the valve member tending to close it. All the four chambers behind these valves are in communication so that a change of pressure in any one is communicated to the others to produce a corresponding adjustment of the flows through each valve. The flow dividing pumps may be positively driven by, for example, an electric motor, in which case a pressure boost from a low-pressure supply may be obtained. Specification 546,350 is referred to.