GB906709A - Pressure fluid operated apparatus - Google Patents

Abstract

906,709. Reciprocating pumps. ROLLSROYCE Ltd. Sept. 21, 1960 [Sept. 28, 1959], No. 32880/59. Class 102 (1). [Also in Groups XXVI and XXIX]. A liquid pressure actuated pump for injecting methanol into a fuel system comprises a double acting piston and cylinder arrangement controlled by a liquid actuated shuttle valve 32. A stepped cylinder 34 houses a piston rod 35 and stepped piston 36, 37. Methanol enters pumping chambers 45, 46 via passages 47, 48 and is delivered via passages 25, 26. In the position shown liquid pressure from a pipe 27 passes to the end 44 of cylinder 34 via passages 74, 73, 62, 75 and 75<SP>11</SP> to move the piston assembly to the left. Shuttle valve 32 is maintained in the position shown by the pressure differential set up by pressure liquid passing to pipes 55 and 56 via a port 81, bore 68 and passages 69 and 72, pipe 55 being closed by piston rod 35 and pipe 56 connected to an outlet 58 by a groove 60. On movement of the piston assembly to the left groove 60 moves out of alignment with pipes 56 and 58 and valve 32 is then maintained in position by the passage of liquid from pipe 56 to an outlet 79 via a passage 78. At the end of the stroke groove 60 is aligned with pipes 55 and 57 so that valve 32 is moved to the left. Pressure liquid then enters the end 54 of cylinder 34 via bore 68 and passages 62, 76 and 76<SP>1</SP> to move the piston assembly to the right for the suction stroke. The pressure liquid outlets lead to the low pressure side of a fuel pump, Fig. 1 (not shown). Fuel under pressure serves as the pressure liquid.