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EP-4739900-A2 - AXIAL PISTON PUMP WITH INTEGRATED AXIAL PISTON ENERGY RECOVERY DEVICE

EP4739900A2EP 4739900 A2EP4739900 A2EP 4739900A2EP-4739900-A2

Abstract

An axial piston pump having an energy recovery system.

Inventors

  • OKLEJAS, JR., ELI
  • OKLEJAS, ROBERT A.

Assignees

  • Fluid Equipment Development Company, LLC

Dates

Publication Date
20260513
Application Date
20240702

Claims (20)

  1. 1. An axial piston pump comprising: a casing having an inlet port and an outlet port; a rotatable barrel having a plurality of cylinders positioned in the housing, the cylinders being disposed to be in communication with the inlet port and the outlet port as the barrel is rotated; a piston moveably positioned in each of the plurality of cylinders, the pistons having a first end and a second end, the first end of the pistons being in communication with inlet port and the outlet port as the barrel is rotated; a plurality of connecting rods having a first end and a second end, the first end of the connecting rods being connected to one of each of the plurality of pistons, the second end of the connecting rods operatively engaging an angled plate; a drive means operatively connected to the barrel to cause the barrel to rotate, rotation of the barrel causing the pistons to be moved in the plurality of cylinders as the second end of the connecting rod is moved along the angled plate; a high-pressure inlet formed in the casing, the high-pressure inlet being in communication with the plurality of cylinders when the cylinders are in communication with the outlet port in the casing, the high-pressure inlet being disposed to be in alignment with the connecting rod and the second end of the piston in the plurality of cylinders; and a low-pressure outlet formed in the casing, the low-pressure outlet being in communication with the plurality of cylinders when the cylinders are in communication with the inlet port in the casing, the low-pressure inlet being disposed to be in alignment with the connecting rod and the second end of the piston in the plurality of cylinders.
  2. 2. The pump of claim 1 wherein the pistons have a first section that is adjacent the inlet port and a second section that is adjacent the connecting rod for the piston.
  3. 3. The pump of claim 2 wherein the second section has a diameter that is larger than the diameter of the first section.
  4. 4. The pump of claim 1 wherein a ceramic seal is positioned in the casing above and below the high-pressure inlet and the low-pressure outlet.
  5. 5. The pump of claim 3 wherein a drain port is disposed in the cylinder adjacent the first section of the piston, the drain port being in communication with an area of the casing adjacent the connecting rod.
  6. 6. The pump of claim 5 wherein a channel extends from the drain port to the area in the casing adjacent the connecting rod.
  7. 7. The pump of claim 1 wherein a lubrication channel extends through the pistons and connecting rods, the end of the lubrication channel and the second end of the connecting rod that is spaced apart from the piston being in communication with the angled plate.
  8. 8. The pump of claim 7 wherein a filter is positioned in the lubrication channel.
  9. 9. The pump of claim 1 wherein the drive means is a motor.
  10. 10. The pump of claim 1 wherein the drive means is a source of fluid under pressure that is operatively connected to the high-pressure inlet.
  11. 11. The pump of claim 10 wherein the source of the fluid under pressure is a high-pressure pump.
  12. 12. The pump of claim 11 wherein the low-pressure outlet is operatively connected to a fluid inlet for high-pressure pump.
  13. 13. The pump of claim 1 wherein the high-pressure inlet port and the low-pressure outlet port extend through the rotatable barrel.
  14. 14. The pump of claim 13 wherein the high-pressure inlet and the low-pressure outlet are disposed to be substantially perpendicular to the connecting rods.
  15. 15. The pump of claim 1 wherein the inlet port and the outlet port pass through the barrel and are in communication with the first end of the pistons.
  16. 16. The pump of claim 15 wherein the inlet port and the outlet port are disposed substantially perpendicular to the connecting rods.
  17. 17. The pump of claim 16 wherein the barrel has a first end that is disposed adjacent a top of the casing.
  18. 18. The pump of claim 17 wherein a bearing pocket is disposed in the casing adjacent the first end of the barrel, a passageway connects the outlet port with the bearing pocket wherein the bearing pocket forms a hydrostatic bearing between the casing and the first end of the barrel.
  19. 19. The pump of claim 18 wherein a needle valve is positioned in the passageway that connects the bearing pocket with the outlet port, the needle valve controlling the flow of fluid from the outlet port to the bearing pocket.
  20. 20. The pump of claim 15 wherein a circumferential passageway has a first area that connects the cylinders with the outlet port and a second area that connects the cylinders with the inlet port.

Description

AXIAL PISTON PUMP WITH INTEGRATED AXIAL PISTON ENERGY RECOVERY DEVICE RELATED APPLICATIONS [0001] This application claims priority to United States Provisional Application No. 63/524,722 filed under 35 U.S.C. § 111(b) on July 3, 2023, the disclosure of which is incorporated herein by reference in its entirety. BACKGROUND OF THE INVENTION [0002] Numerous industrial fluid-based processes involve a process stream that needs to be pressurized to a high level required to achieve a transformation of the process stream in a beneficial manner. The stream entering the process is called the input stream. The output of the process may be a single output stream or multiple output streams with one or more of the output streams retaining a substantial fraction of the input pressure. High-pressure output streams hold the possibility of recovering hydraulic energy to reduce net energy consumption. [0003] Figure 1-A depicts a reverse osmosis desalination system. The input stream, seawater in this example, enters through pipe 1 and is pressurized by high-pressure pump 2 to about 55 to 65 bars before admitted into reverse osmosis (RO) membranes 3. RO membranes 3 selectively block dissolved substances from crossing the semi-permeable membrane of the RO element and thus a portion of the input stream is purified and exits through pipe 4 at low pressure. Anywhere from 35-50 percent of the input stream is purified and 50-65 percent of the input stream exits membrane 3 as an output brine stream at a pressure slightly less than input stream in pipe 1 through pipe 5 and control valve 6 to drain 7. This output brine stream offers the potential for recovering hydraulic energy. Figure 1-B shows an energy recovery device 8 that transfers energy from output stream in pipe 5 to input stream in pipe 1. Note that input stream has a flow substantially higher than output stream. [0004] Figure 1-C depicts a liquid-based absorption process used to purify gases such as natural gas. Raw gas enters contractor 52 by pipe 1. Liquid absorbent is sprayed from nozzles 53 at the top of contractor to absorb CO2 from the gas flowing upwards to exit through pipe 54 as purified gas. The absorbent, now laden with contaminants, collects at the bottom and exits through pipe 58 through control valve 57 regulated by liquid level monitor 56. The output stream of absorbent enters stripper 59 which removes contaminants from the liquid absorbent with contaminates exiting through pipe 60 and then is admitted through pipe 61to pump 55 that repressurizes the absorbent to the pressure in contractor 52 thus completing the purification cycle. Typical contractor pressure is 60 bar and stripper pressure well below 10 bar thus there is significant hydraulic energy available for recovery. Figure 1-D shows an energy recovery device 8 that transfers hydraulic energy from the output stream flowing through pipe 58 to the input stream flowing through pipe 61. Note that the input and output streams have similar flow rates. [0005] The process above has an input stream flowrate approximately equal to the output stream flowrate. Also, the output stream is laden with gaseous components that will come out of solution when the pressure is reduced hence the volume of the output stream can exceed the input stream as well as contain additional energy available from the expansion of the gaseous component. [0006] The invention described herein can accommodate the above operating scenarios. [0007] Many types of hydraulic energy recovery devices have been developed. The most numerous use a turbine to recover hydraulic energy. The mechanical energy generated by the turbine can be used to help drive the pressurization pump or be used for another application. Turbine-based energy recovery is most feasible for high flow rates (above 100 m3/hr.) which is favorable to high efficiency. Lower flows have a negative effect on efficiency thereby reducing the economic justification for using such equipment. Positive displacement energy recovery devices can have high efficiency at low flow rates but are generally expensive thereby reducing the economic justification. [0008] The present invention is an improvement in process hydraulic energy recovery by combining the pressurization pump and the depressurization energy recovery device into a single unit using positive displacement. Combining the high-pressure pump and energy recovery device into one unit reduces the cost and complexity of the system resulting in a greater economic justification to apply energy recovery to various processes. The additional flexibility of handling input and output streams of differing flow rates with gaseous components increases the range of application and energy recovery potential. DESCRIPTION OF THE PRIOR ART [0009] Figures 2 and 3 show a typical axial piston pump relevant to the present invention. Casing 75 and end caps 72 and 21 are attached by bolts 74-A and 74-B and bolts 22-A and 22-B respectively. Shaft 24 with ke