Patent GB-896185-A (GB)
Title: A fluid operated well pump
Inventor: COBERLY CLARENCE JAMES
IPC: F04B47/08
Filed: 1960-03-09
Abstract: 896,185. Fluid-operated well pumps. KOBE Inc. March 9, 1960, No. 8323/60. Class 102(1). [Also in Group XXIX] A fluid-operated well pump including at least two axially, tandem connected, fluid-operated pump units, each unit comprising a pump and an engine, said pump units cooperating to sustain full pumping load and wherein a valve device controlling the supply and exhaust of operating fluid to and from each of said engines is operable by the pump units to progressively apply the pumping load to said pump units in sequence and to remove the pumping load from each of said pump units as the pumping load is applied to another of said pump units. As shown in Fig. 1, the pump comprises two fluid-operated pump units 14a, 14b spaced apart and connected in series in a tube 22 to pump crude oil entering the tube at 40 to the surface. Each pump unit comprises a pump and an engine constituted by a cylindrical fixed block 90a through which slides a tubular rod 30a carrying pistons 26a, 32a at its ends and a valve 42a controlling flow through the bore 38a of the rod. The undersurface of each piston 26a is constantly under pressure of operating fluid, usually clean crude oil, supplied through tubing 18 and a passage 44 whilst the upper surface of each piston 32a is alternatively connected to the supply of operating fluid and exhaust. The pistons 32a and the tube portions in which they slide are slightly larger in diameter than the-pistons 26a and the tube portions in which they slide, so that when the upper surfaces of the pistons 32a are open to exhaust the pumps perform their working strokes and when open to pressure their return strokes. Slide valves 56a, 56b fitted in the tube 18 control the supply and exhaust of operating fluid to and from the upper surface of the piston 32a. As shown in Fig. 1, the pump unit 14a is nearly at the completion of its working stroke pushing the oil previously pumped up the tube 22, the pump unit 14b has completed or nearly completed its return stroke during which oil is sucked through the bore 38b and transferred to the tube portion 28b. The lower valve 56b is held in its upper position by operating fluid supplied from the pipe 18 through the passage 44, passage 70a, bore 64a, restricted passage 84a and passage 74a so that communication is cut between a supply passage 70b and restricted passage 84b and passage 74b connected to the upper valve 56a. The lower face of the upper valve 56a at this time being connected to exhaust through the passage 74b, restricted passage 84b, bore 64b and passage 50b to hold the valve 56a in its lower position. As the pump unit 14a moves upwardly a control groove 80a in its rod 30a interconnects passages 76a, 78a so that the space below the lower valve 56b is connected to exhaust through passages 74a, 76a, 78a and 50a whence the valve 56b moves downwardly connecting the upper face of the piston 32a of the lower unit to exhaust through passages 48b, bore 64b and passage 50b whence the pump unit 14b commences its upward working stroke prior to the pump unit 14a completing its working stroke to prevent sudden pressure changes. On the valve 56b reaching its lower position the under surface of the valve 56a is opened to pressure through passages 44, 70b, bore 64b, restricted passage 84b and passage 74b so that the valve 56a is moved slowly upwards due to the restricted passage 84b, to slowly connect the upper face of the piston 32a of the upper unit 14a to pressure through passages 44, 52a, bore 64a and passage 48a to slow down the final upward movement of the pump unit 14a prior to the commencement of its return stroke. Similarly the pump unit 14b will control the valve 56a which in turn will control the valve 56b to control the pump unit 14a which as before commences its pumping stroke before the pump unit 14b finishes its pumping stroke. Another embodiment is described in which three pump units in axial alignment one behind the other are associated with three sliding valves. The pump units operating in sequence in overlapping relation so that at any one time at least one of the pumps is carrying out its pumping stroke.