GB598922A - Hydraulic mechanism for effecting reciprocation of a pump - Google Patents

Abstract

598,922. Liquid - pressure engines. DEHN, F. B. (Alco Valve Co.). June 8, 1945, No. 14573. [Class 69 (ii)] In a hydraulic mechanism for reciprocating a pump, a reverse valve 16 controls the flow of pressure fluid to and from the opposite ends of a cylinder 13 to reciprocate therein a piston 12 which is connected to the pumping device S to be actuated. A continuously operating pump 19 delivers pressure fluid through a line 17 to the reverse valve 16 which latter is connected by fluid lines 14, 15 to opposite ends of the cylinder 13, said reverse valve comprising a casing provided with reciprocating valves 25, 26, 27 and fluid passages whereby the pressure fluid is alternately conducted into one and then into the other of the fluid lines 14, 15, the fluid line not connected with the pressure line 17 being connected by passages in said casing and controlled by said reciprocating valves to a discharge line 18. As shown in Fig. 2, pressure fluid flows from the inlet 17 through an open passage 44 to a passage 45 leading to the line 14 to raise the piston 12. At the same time, fluid displaced from above the piston 12 escapes. through the line 15 and passages 49, 57, 55 and 53 to the discharge line 18. Pressure fluid from the passage 45 also traverses a passage 46 to a chamber 32 beyond one end of the piston valve 25. A spring 35 in the chamber 32 holds apart two apertured washers 33, 34 on an extension 31 of the piston valve 25 to hold the valve in the neutral position shown. When the piston 12 reaches the end of its stroke, or meets an obstruction, the pressure builds up to a predetermined value at which it moves the valve 25 to the left, compressing the spring 35. Fluid displaced by the opposite end of the valve 25 escapes through a passage 50 to the passage 49 and so to the discharge line 18. By the movement of the piston valve 25, collars on it cease to obstruct passages 60, 62 leading to the ends of the chamber of the second piston valve 26 and face the hydraulic lock thereon; the passage 62 is opened to the pressure line 17 and the passage 60 to the discharge line 18. The valve 26 moves quickly to the right and a central collar thereon passes the fluid pressure passage 44 permitting the fluid to traverse a restricted passage 66 leading to one end of the chamber containing the third piston valve 27, while a similar passage 64 at the other end of the chamber becomes open to the passage 53 and discharge line 18. The valve 27 moves slowly to the right reversing the connections to the lines 14, 15. The passage 46 is now open to the discharge line 18 and the pressure of the spring 35 returns the valve 25 to its neutral position.