Patent GB-927098-A (GB)
Title: Hydraulic engine
Inventor: SARGENT EDWARD JOSEPH
IPC: F04B47/08
Filed: 1959-12-22
Abstract: 927,098. Reciprocating pumps. SARGENT RODLESS PUMP CO. Dec. 22, 1959, No. 43584/59. Addition to 831,394. Class 102(1). [Also in Group XXIX] A liquid-pressure engine 14 for operating a deep well pump 12 comprises a piston 17 reciprocable in a cylinder 18 formed in a stationary member, a valve housing 53 fixed relative to the piston and having a main valve 69, 70 controlling the fluid supply to, and exhaust from, the cylinder, the main valve being movable by a pilot valve having first and second separable parts 80, 81 mounted to slide in a bore in the valve housing and co-operable with the stationary member, both parts being movable at the end of the power stroke of the piston and only one part 81 being movable at the end of the exhaust stroke, and a passage 90 in the housing which introduces fluid pressure between the pilot valve parts to separate them axially and is blocked by the shifting of the part 81 at the end of the exhaust stroke. The engine 14 is lowered into a casing 11 by a tubing 15 until the pump 12 rests on a shoe 13. Fluid pressure supplied through the tubing 15 to the motor passes into a tube 46 connected to the piston of the motor. A pressure chamber 45 beneath the piston is connectible to the pressure in the tube 46 to move the piston upwardly and to exhaust so that pressure acting on the upper surface of the tube 46 moves the piston downwardly to reciprocate the plunger 20 of the pump, the fluid pumped passing through ports 26 to enter a chamber 27 to mix with fluid exhausted through ports 29 from the motor. The control of fluid to the pressure chamber 45 is effected by the main valve which is in two parts 69, 70 to prevent misalignment between its operative surfaces. The upper part 69, when in its lowermost position, connects the fluid pressure in the tube 46 with a passage 72 leading to the chamber 45; in the uppermost position of the valve, the passage 72 is connected to a further passage 74 leading to a discharge space 75, annular passage 77 and exhaust chamber 28. The main valve is controlled by the pilot valve parts 80, 81. During the downstroke of the piston the valve parts are separated by fluid pressure from the tube 46 passing through the passage 90. The fluid pressure also passes through a bore 94 in the valve part 81 and passages 92, 93 to the space below the main valve part 70 which is thus urged upwardly to the position shown in Fig. 3, in which position the pressure chamber 45 is connected to the exhaust chamber 28. At the lower end of the stroke of the piston, the pilot valve part 81 is moved relative to the valve housing by a ring 84 abutting a surface 98 to cut-off the supply of fluid pressure to the space below the main valve part 70 which is then vented to exhaust by passages 91 and 74 so that the main valve moves downwardly and connects the pressure in tube 46 to the pressure chamber to move the piston 17 upwardly; the part 81 also blocks the passage 90 so that the parts 80, 81 are not separated. At the upper end of the stroke of the piston, the pilot valve part 80 is moved downwardly relative to the housing by a ring 76 abutting a surface 101 and in turn moves the lower part 81 to reconnect the fluid to the lower part of the main valve to connect the chamber 45 to exhaust. Movement of the part 81 also uncovers the passage 90 so that the fluid pressure again separates the parts 80, 81. A dashpot effect is provided at the ends of the stroke of the piston by portions 50, 55 entering recesses 51, 56.