Series submersible diaphragm pump

Abstract

The invention discloses a series submersible diaphragm pump. The system comprises a submersible motor, a protector and oil-submerged pumps, the submersible motor, the protector and the oil-submerged pumps are sequentially connected from bottom to top, and more than two oil-submerged pumps are sequentially connected in series in the axial direction; the oil-submerged pumps are connected in series through the camshaft; the well fluid channels of the oil-submerged pumps are sequentially communicated, and the well fluid channel of the oil-submerged pump located at the uppermost end is communicated with an oil pipe. A cam shaft and a pump body are arranged in a pump cylinder of the oil-submerged pump in parallel in the axial direction, and the well fluid channel is arranged in the axial direction of the pump body. The diaphragm pump has the beneficial effects that the diaphragm pump is formed by connecting multiple sections of diaphragm pump monomers in series, large-displacement operation can be realized, and different sections of diaphragm pumps can be designed according to the yield of an oil well, so that the displacement can be adjusted; the diaphragm pump, the protector and the motor adopt modular design, so that the maintenance is convenient, and the problem of many faults caused by threading of a cable from the interior of the pump is solved; the upper and lower protectors separate pressure liquid from motor oil, so that the temperature rise of the motor can be effectively reduced, the working temperature of the diaphragm is reduced, and the service life of the diaphragm pump is prolonged.

Description

Technical Field

[0001] The invention relates to a submersible pump, in particular to a series submersible diaphragm pump, and belongs to the technical field of oil and gas development. Background Art

[0002] As oilfield development enters the late stages of production, individual well production continues to decline, leading to a gradual expansion in the use of small and medium-displacement electric submersible pumps. Simultaneously, the increasing number of water extraction and degassing operations in coalbed methane production, characterized by small displacement and long duration, has increased demand for small and medium-displacement electric submersible pumps. Currently, small and medium-displacement electric submersible pumps primarily consist of submersible screw pumps and conventional submersible diaphragm pumps. Conventional submersible diaphragm pumps are integrated, with the diaphragm pump, protector, and motor housed within a single steel cylinder. Due to structural design flaws and numerous field operation issues, their widespread adoption has been hindered. Key challenges include non-adjustable displacement and a limited range of applications; a shared lubricating oil system, resulting in poor heat dissipation and rapid temperature rise; internal cable routing, making power connections difficult and prone to failure; and manufacturing difficulties and high costs. Submersible screw pumps, when used in small-displacement wells, suffer from low energy efficiency and a short lifespan. Furthermore, screw pumps are expensive, making market adoption difficult. Summary of the Invention

[0003] In order to overcome the above-mentioned deficiencies of existing submersible screw pumps and conventional submersible diaphragm pumps in the production process of small-displacement oil wells and water-producing and exhaust-gas coalbed methane wells, the present invention provides a series submersible diaphragm pump.

[0004] The technical solution adopted by the present invention to solve its technical problems is: a series submersible diaphragm pump, including a submersible motor, a protector, and a submersible pump. The submersible motor, the protector, and the submersible pump are connected in sequence from bottom to top, and more than two submersible pumps are connected in series in sequence along the axial direction; the submersible pumps are connected in series through a camshaft; the well fluid channels of the submersible pumps are connected in sequence, and the well fluid channel of the submersible pump located at the uppermost end is connected to the oil pipe.

[0005] A camshaft and a pump body are arranged in parallel along the axial direction in the pump barrel of the submersible pump, and the well fluid channel is arranged along the axial direction of the pump body.

[0006] The pump body is provided with a liquid inlet valve, a diaphragm pump, and a liquid discharge valve in sequence from bottom to top, and a liquid flow channel is provided between the liquid inlet valve, the diaphragm pump, and the liquid discharge valve. The liquid flow channel is provided with a liquid inlet channel, a diaphragm cavity, and a liquid discharge channel in sequence in the pump body; the liquid discharge hole provided in the pump body above the liquid discharge valve is connected to the well liquid channel.

[0007] The diaphragm pump is arranged radially along the pump barrel and is driven by a camshaft.

[0008] When the cam of the camshaft moves toward the bottom dead center, the volume of the diaphragm cavity increases, the liquid inlet valve opens, and the well fluid is sucked in.

[0009] When the cam of the camshaft moves toward the upper dead center, the volume of the diaphragm cavity decreases, the drain valve opens, and the well fluid is discharged.

[0010] The pump barrel below the liquid inlet valve is provided with a screen pipe for well fluid to enter.

[0011] Furthermore, adjacent camshaft ends are connected by splines.

[0012] Furthermore, the submersible pump arranged at the bottom is connected to the protector through a connecting device.

[0013] A transmission mechanism is provided in the connecting body of the connecting device, and the transmission mechanism converts the axial rotation of the motor shaft into the eccentric rotation of the cam shaft.

[0014] The transmission mechanism comprises an external gear pair, an intermediate shaft, and an internal gear pair which are sequentially connected from top to bottom; the lower end of the transmission mechanism is connected to the protector.

[0015] The protector includes an upper protector for providing pressure liquid to the submersible pump and a lower protector for providing motor oil to the submersible motor. The upper protector and the lower protector are connected in sequence, and a mechanical sealing device is provided at the connection between the upper protector and the lower protector.

[0016] The beneficial effects of the present invention are that the structural design is reasonable, and multiple diaphragm pump units are connected in series to form a diaphragm pump, which can achieve large-displacement operation. At the same time, diaphragm pumps with different numbers of sections can be designed according to the oil well production to achieve adjustable displacement; the diaphragm pump, protector and motor adopt a modular design, which is easy to maintain and solve the problem of frequent failures of cables passing through the inside of the pump; the upper and lower protectors separate the pressure liquid and motor oil, which can effectively reduce the temperature rise of the motor, reduce the working temperature of the diaphragm, and extend the service life of the diaphragm pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of the series submersible diaphragm pump of the present invention.

[0018] Figure 2 It is a schematic structural diagram of the diaphragm pump in the present invention.

[0019] Figure 3 yes Figure 2 AA cross-section diagram.

[0020] In the figure: 1. spline, 2. bearing, 3. camshaft, 4. external gear pair, 5. intermediate shaft, 6. internal gear pair, 7. diaphragm support plate, 8. return spring, 9. support rod, 10. diaphragm, 11. diaphragm cavity, 12. drainage hole, 13. drainage valve, 14. drainage channel, 15. inlet channel, 16. inlet valve, 17. screen pipe, 18. well fluid channel, 19. oil pipe, 20. upper protector, 21. lower protector, 22. pump body, 23. joint, 24. transmission shaft, 25. straightening frame, 30. pump barrel, 40. diaphragm pump, 100. submersible motor, 200. protector, 300. submersible pump, 400. connecting device, 401. connecting body, 402. transmission mechanism. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and examples. However, those skilled in the art should be aware that the present invention is not limited to the specific embodiments listed, and any embodiments that conform to the spirit of the present invention should be included within the scope of protection of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "vertical", "up", "down", "left", "right", "horizontal", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing or simplifying the description of the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," "connected," and "sealed" should be understood broadly. For example, a connection can be fixed or removable, direct, indirect, or integral; it can be mechanical, indirectly connected through an intermediate medium, or internally connected between two components. A seal can be an oil seal, a packing seal, or other forms of seal. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0024] See attached Figure 1 The present invention provides a series submersible diaphragm pump, comprising a submersible motor 100, a protector 200, and a submersible pump 300. The submersible motor 100, the protector 200, and the submersible pump 300 are sequentially connected from bottom to top, and two or more submersible pumps 300 are sequentially connected in series along the axial direction.

[0025] The submersible pumps 300 are connected in series via the camshafts 3 , and adjacent ends of the camshafts 3 are connected using splines.

[0026] The well fluid passages 18 of the submersible pumps 300 are connected in sequence, and the well fluid passage 18 of the submersible pump 300 at the uppermost end is connected to the oil pipe 19 .

[0027] See attached Figure 2 、 3 The camshaft 3 and the pump body 22 are axially arranged in parallel within the pump barrel 30 of the submersible pump 300. The well fluid passage 18 is axially arranged along the pump body 22. Preferably, there are two well fluid passages 18. Typically, the well fluid passage 1 axially penetrates the pump body 22. The lower end of the well fluid passage 1 located at the bottom of the pump body 22 of the submersible pump 300 can be blocked.

[0028] The pump body 22 is provided with a liquid inlet valve 16, a diaphragm pump 40, and a liquid discharge valve 13 from bottom to top. A liquid flow channel is provided between the liquid inlet valve 16, the diaphragm pump 40, and the liquid discharge valve 13. The liquid flow channel is composed of a liquid inlet channel 15, a diaphragm cavity 11, and a liquid discharge channel 14 that are connected in sequence in the pump body 22; the liquid discharge hole 12 provided in the pump body 22 above the liquid discharge valve 13 is connected to the well liquid channel 18.

[0029] The diaphragm pump 40 is arranged radially along the pump barrel 30 , and the diaphragm pump 40 is driven by the camshaft 3 .

[0030] Furthermore, when the cam of the camshaft 3 moves toward the bottom dead center, the volume of the diaphragm cavity 11 increases, and the liquid inlet valve 16 opens to complete the well fluid suction.

[0031] Furthermore, when the cam of the camshaft 3 moves toward the top dead center, the volume of the diaphragm cavity 11 decreases, and the drain valve 13 opens to discharge the well fluid.

[0032] The pump barrel 30 below the liquid inlet valve 16 is provided with a screen pipe 17 for well fluid to enter.

[0033] The submersible pump 300 disposed at the bottom is connected to the protector 200 via a connecting device 400 .

[0034] Furthermore, a transmission mechanism 402 is provided in the connecting body 401 of the connecting device 400 , and the transmission mechanism 402 converts the axial rotation of the motor shaft into the eccentric rotation of the camshaft 3 .

[0035] The transmission mechanism 402 includes an external gear pair 4 , an intermediate shaft 5 , and an internal gear pair 6 , which are sequentially connected from top to bottom. The lower end of the transmission mechanism 402 is connected to the protector 200 .

[0036] The protector 200 includes an upper protector 20 for providing pressure liquid to the submersible pump 300 and a lower protector 21 for providing motor oil to the submersible motor 100. The upper protector 20 and the lower protector 21 are connected in sequence, and a mechanical sealing device is provided at the connection between the upper protector 20 and the lower protector 21.

[0037] Example:

[0038] A series submersible diaphragm pump includes a submersible motor 100, a protector 200, a submersible pump 300 and a connecting device 400. The protector 200 includes an upper protector 20 and a lower protector 21. The submersible motor 100, the lower protector 21, the upper protector 20, the connecting device 400, and the submersible pump 300 are connected in sequence from bottom to top. Two submersible pumps 300 are connected in series according to the well fluid displacement (such as Figure 1 As shown), the upper end of the submersible pump 300 arranged at the top is connected to the oil pipe 19 through a joint 23, and the submersible motor 100 is an asynchronous submersible motor; wherein: the submersible motor 100 is a power output unit, the protector 200 is a power transmission unit, and the submersible pump 300 / diaphragm pump 40 is a power execution unit.

[0039] The submersible pump 300 includes a pump barrel 30, a diaphragm pump 40, a pump body 22, a camshaft 3, a liquid inlet valve 16, and a liquid discharge valve 13. The camshaft 3 and the pump body 22 are arranged in parallel along the axial direction in the pump barrel 30 (as shown in FIG. Figure 2 、 3 The cam is arranged in the middle of the camshaft 3. The diaphragm pump 40 is arranged radially along the pump barrel 30, and the diaphragm pump 40 is rotationally driven by the camshaft 3.

[0040] The diaphragm pump 40 includes a diaphragm support plate 7, a return spring 8, a support rod 9, and a diaphragm sheet 10. The cam of the camshaft 3 is connected to one end of the support rod 9. The return spring 8, the diaphragm support plate 7, and the diaphragm sheet 10 are installed on the axial diameter of the support rod 9 from left to right. The diaphragm support plate 7 and the diaphragm sheet 10 are located in the diaphragm cavity 11 on the right side of the pump body 22 (as shown in FIG. Figure 2 、 3 As shown in FIG, a carbon fiber skeleton is provided inside the diaphragm 10 to increase its strength, and a diaphragm support plate 7 is installed on the back thereof to push the diaphragm to agitate. The camshaft 3 rotates and the cam drives the support rod 9 to realize the reciprocating motion of the diaphragm 10.

[0041] The pump body 22 is provided with an inlet valve 16, a diaphragm pump 40, and a discharge valve 13 from bottom to top. The inlet valve 16, the diaphragm pump 40, and the discharge valve 13 are connected in sequence through the inlet channel 15, the diaphragm cavity 11, and the discharge channel 14 provided in the pump body 22; the pump body 22 located above the discharge valve 13 is provided with a radial discharge hole 12, and the discharge hole 12 is connected to the well fluid channel 18.

[0042] The pump barrel 30 below the liquid inlet valve 16 is provided with a screen tube 17 , and the well fluid enters the pump body 22 through the screen tube 17 .

[0043] The well fluid passage 18 is arranged along the axial direction of the pump body 22, and the number of the well fluid passage 18 is 2 (such as Figure 3As shown), the well fluid channel 1 axially penetrates the pump body 22, and the well fluid channels 18 of the submersible pumps 300 connected in series are connected in sequence. The lower end of the well fluid channel 1 of the pump body of the lowest submersible pump 300 is blocked.

[0044] To support the camshaft 3 and prevent it from moving up and down, bearings 2 are mounted near each end of the camshaft 3. Preferably, the bearings 2 are a set of double-row tapered roller bearings. A centralizing bracket 25 can also be installed on the inner wall of the pump barrel 30 on the side where the camshaft 3 is mounted to radially support the camshaft 3 and ensure its rotational stability.

[0045] The camshaft 3 is provided with splines at both ends. The splines 1 of adjacent submersible pumps 300 are located within the connector 23, connecting the camshafts 3 of adjacent submersible pumps 300 via the splines 1. The camshaft 3 is provided with a spline shaft at the upper end and a spline sleeve at the lower end. The connector 23 is provided with an axial through-hole corresponding to the well fluid passage 18 of the pump body 22.

[0046] The submersible pump 300 at the lower end of the series submersible diaphragm pumps is connected to the protector 200 via a connecting device 400 .

[0047] The connecting device 400 includes a connecting body 401 and a transmission mechanism 402. The transmission mechanism 402 is arranged in the connecting body 401. The upper end of the transmission mechanism 402 is connected to the camshaft 3, and the lower end of the transmission mechanism 402 is connected to the protector 200, converting the axial rotation of the motor shaft into the eccentric rotation of the camshaft 3.

[0048] The transmission mechanism 402 includes an external gear pair 4, an intermediate shaft 5, and an internal gear pair 6, which are sequentially connected from top to bottom. The lower end of the transmission mechanism 402 is connected to the protector 20. In this embodiment, a transmission shaft 24 is mounted on the lower end of the internal gear pair 6 and is connected to the protector 200 via a spline.

[0049] The protector 200 includes an upper protector 20 and a lower protector 21. The upper protector 20 provides pressure fluid to the submersible pump 300, and the lower protector 21 provides motor oil to the submersible motor 100. The upper and lower protectors 20 and 21 are connected in sequence, and a mechanical seal is provided at the connection between the upper and lower protectors 20 and 21. By providing the upper and lower protectors 20 and 21, the pressure fluid and motor oil are separated, which can effectively reduce the temperature rise of the motor, lower the operating temperature of the diaphragm, and extend the service life of the diaphragm pump.

[0050] The working process of the series submersible diaphragm pump of the present invention is:

[0051] When the cam of the camshaft 3 moves toward the bottom dead center, the volume of the diaphragm cavity 11 of the diaphragm pump 40 increases, the liquid inlet valve 16 opens, and the well fluid enters the pump body 22 through the screen tube 17, and then enters the diaphragm cavity 11 through the liquid inlet valve 16 and the liquid inlet channel 15, completing the well fluid suction.

[0052] When the cam of the camshaft 3 moves toward the upward dead center, the volume of the diaphragm chamber 11 of the diaphragm pump 40 changes from large to small, the liquid inlet valve 16 is closed, and the liquid discharge valve 13 is opened. The well fluid in the diaphragm chamber 11 passes through the liquid discharge valve 13, the radial liquid discharge hole 12, and the well fluid channel 18 in sequence, and is discharged into the oil pipe 19.

[0053] The submersible pump, protector and motor of the series submersible diaphragm pump of the present invention are modularly designed and are independent units of each other; the submersible pump is an execution unit, and multiple sections of submersible diaphragm pump units can be connected in series according to the displacement requirements. Each section of the submersible diaphragm pump unit pushes the support rod through the camshaft, and then pushes the diaphragm to reciprocate and pump out the well fluid; the protector is divided into two sections, the upper section provides pressure liquid for the submersible pump, and the lower section provides motor oil for the submersible motor. Separating the pressure liquid and the motor oil can effectively reduce the temperature rise of the motor, reduce the working temperature of the diaphragm, and extend the service life of the diaphragm pump.

[0054] The tandem submersible diaphragm pump of the present invention adopts a modular design, which can reduce costs and facilitate maintenance and servicing; it has the advantages of adjustable displacement, high efficiency, low failure rate, and low cost, and can meet the production requirements of wells with complex wellbore structures such as corroded wells, sand-containing wells, small-displacement oil wells, and coalbed methane wells.

[0055] It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the claims.

Claims

1. A series submersible diaphragm pump, comprising a submersible motor, a protector, and a submersible pump, characterized by: The submersible motor, protector and submersible pump are connected in sequence from bottom to top, and two or more submersible pumps are connected in series in sequence along the axial direction; The submersible pumps are connected in series via a camshaft; the well fluid channels of the submersible pumps are connected in sequence, and the well fluid channel of the submersible pump located at the uppermost end is connected to the oil pipe.

2. The tandem submersible diaphragm pump according to claim 1, characterized in that: A camshaft and a pump body are arranged in parallel along the axial direction in the pump barrel of the submersible pump, and the well fluid channel is arranged along the axial direction of the pump body.

3. The tandem submersible diaphragm pump according to claim 2, characterized in that: The pump body is provided with a liquid inlet valve, a diaphragm pump, and a liquid discharge valve in sequence from bottom to top, and a liquid flow channel is provided between the liquid inlet valve, the diaphragm pump, and the liquid discharge valve. The liquid flow channel is provided with a liquid inlet channel, a diaphragm cavity, and a liquid discharge channel in sequence in the pump body; the liquid discharge hole provided in the pump body above the liquid discharge valve is connected to the well liquid channel; The diaphragm pump is arranged radially along the pump barrel and is driven by a camshaft.

4. The tandem submersible diaphragm pump according to claim 3, characterized in that: When the cam of the camshaft moves to the bottom dead center, the volume of the diaphragm cavity increases, the liquid inlet valve opens, and the well fluid is sucked in. When the cam of the camshaft moves toward the upper dead center, the volume of the diaphragm cavity decreases, the drain valve opens, and the well fluid is discharged.

5. The tandem submersible diaphragm pump according to claim 4, characterized in that: The pump barrel below the liquid inlet valve is provided with a screen pipe for well fluid to enter.

6. The tandem submersible diaphragm pump according to claim 1, characterized in that: The adjacent camshaft ends are connected by splines.

7. The tandem submersible diaphragm pump according to claim 1, characterized in that: The submersible oil pump arranged at the bottom is connected to the protector through a connecting device.

8. The tandem submersible diaphragm pump according to claim 1, characterized in that: A transmission mechanism is provided in the connecting body of the connecting device, and the transmission mechanism converts the axial rotation of the motor shaft into the eccentric rotation of the cam shaft.

9. The tandem submersible diaphragm pump according to claim 8, characterized in that: The transmission mechanism comprises an external gear pair, an intermediate shaft, and an internal gear pair which are sequentially connected from top to bottom; the lower end of the transmission mechanism is connected to the protector.

10. The tandem submersible diaphragm pump according to claim 1, characterized in that: The protector includes an upper protector for providing pressure liquid to the submersible pump and a lower protector for providing motor oil to the submersible motor. The upper protector and the lower protector are connected in sequence, and a mechanical sealing device is provided at the connection between the upper protector and the lower protector.

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