Patent GB-481201-A (GB)
Title: Improvements in and relating to motors for pumping and similar uses
IPC: F01L25/06
Filed: 1936-09-15
Abstract: 481,201. Engine valve-gear. TRIGGS, W. W. (Sullivan Machinery Co.) Sept. 15, 1936, No. 25120. [Classes 122 (ii) and 122 (iii)] [Also'in Group XXVIII] In single-acting pumping mechanism applied to a well, separate inlet and exhaust lift valves, or a slide valve controlling both admission and exhaust, have associated with them fluidpressure actuating-areas which are alternately put to pressure and exhaust by cylinder connections controlled by the pistons and non-return valves. Each passage is connected at two points to the cylinder, which are so arranged that the piston in its working- stroke must pass beyond both points before inlet to the areas can take place, and must pass both points oppositely in its return stroke before exhaust can occur. A compressed-air operated pump for oil wells is shown in Fig. 1. The motor 6 is supported by a member 3 mounted upon a frame 2, and carries a valve chest 8 supplied with air which passes from a compressor through a pipe 10, a preheater 11, past a stop valve 13, a vent valve 15, an automatic control valve 14 to the chest 8, the exhaust returning to the compressor. The admission and exhaust valves are arranged beneath the cylinder as shown in Fig. 2. A piston of two diameters 38, 39 is connected to the admission valve 37. The piston 38 is of the same area as the port 35. The annular piston area is open to exhaust. The cylinder of piston 39 is connected to the main cylinder at points 51, 57 through passages 44, 50, 47, 56. The passages contain spring- pressed non-return ball valves which permit fluid to pass through passage 50 to the piston 39, and from piston 39 to the passage 56. The passage 50 is connected to a casing with a hand-controlled valve which permits communication with the cylinder at a point 52. A piston of two diameters 71, 73 is associated with the exhaust valve 59 the port controlled by which is equal in area to the piston head 71. The valve has a spring-pressed stem 66 which is reduced at 66b and enters a bore in the piston. The top of the piston 73 is connected by passages 76, 81, 84 with the main cylinder. At the top it communicates with the port 52, and at the bottom with a port connection 85 or 57, depending upon the position of the valve mechanism 86, Fig. 3. The passages contain spring-pressed, non- return, ball valves. Pressure fluid may pass from the top end of the cylinder to the valve chamber, or from the valve-chamber to the bottom end of the cylinder. Plugs 87 permit adjustment of the connection points 51, 85. The cylinder ports associated with the passages control the connection ; the port at 51 controls the expansion. In the position shown in Fig. 2, fluid-pressure at 250 or 300 lb. per square inch will raise the piston 20. If the port at 51 controls the expansion, as the piston passes the port the valve 37 is closed. Upon the piston passing port 52 the exhaust valve 59 is opened. The weight of the rod line &c. moves the piston down against the back pressure which is above atmospheric in the discharge line 16 leading to the compressor. When the piston moving down uncovers the port at 85, if the adjustment of the valve mechanism at 86 permits, the exhaust valve 59 will close under the pressure on head 71 and the spring 67. When the piston uncovers port 57, fluid will escape from the top of piston 39 and the compression in the cylinder will open the admission valve. A modification, Figs. 6-8 (not shown), is described wherein the spring-pressed balls in the cylinder connections are replaced by spring-pressed conical valves mounted in the cover of the auxiliary cylinders and in the pistons 39, 73 respectively. When the piston moves up, the closing of the admission valve and the opening of the exhaust valve are initiated by fiuid-pressure from the upper end of the cylinder and completed by fluid from the lower end of the cylinder. A modification is described wherein the valve is formed as a piston valve with differential piston heads sliding transversely to the end of the main cylinder. It works under a supply pressure of 200-300 lb. per square inch and an exhaust pressure of 75-100 lb. per square inch. The upper end of the cylinder is provided with a series of byepasses, and a non-return valve with. a leakage port which is normally open to admit or exhaust air, but is closed upon the plunger-rod breaking by the sudden rush of air produced by the up movement of the piston. Specification 423,925 is referred to.