A self-driven rotary pressure energy recovery device with built-in guide impeller structure

Abstract

This invention discloses a self-driven rotary pressure energy recovery device with a built-in guide impeller structure, comprising an outer sleeve, an upper end cover, a lower end cover, and a rotor. The rotor is coaxially and rotatably mounted inside the outer sleeve, with a clearance fit between the rotor and the outer sleeve. The upper end cover is sealed to one end of the outer sleeve, and the lower end cover is sealed to the other end of the outer sleeve. An upper impeller is coaxially driven to one end of the rotor, and a lower impeller is coaxially driven to the other end of the rotor. In this invention, through the built-in impeller structure of the rotor, high and low pressure fluids flow into the impeller through the inlet, impacting the impeller. The fluid velocity is converted into tangential velocity, driving the rotor to rotate and providing kinetic energy for the rotor's rotation. This achieves self-drive of the rotor and stable rotational speed, thus eliminating the need for additional kinetic energy supply to the device, improving the stability and reliability of the entire system, and enabling the device to operate under a wider range of conditions.

Description

Technical Field

[0001] This invention relates to the field of seawater desalination technology. Specifically, it relates to a self-driven rotary pressure energy recovery device with a built-in guide impeller structure. Background Technology

[0002] In processes such as reverse osmosis seawater desalination, petrochemicals, and industrial reverse osmosis water treatment systems, high-pressure waste liquids are often directly discharged or treated by throttling. Because the discharged liquids still have high pressure energy, this results in a huge waste of energy and an increase in the overall energy consumption of the process.

[0003] Energy saving is the key to the success of reverse osmosis seawater desalination technology, but energy consumption remains the most significant factor limiting the system's operating costs. In the entire reverse osmosis seawater desalination process, the residual pressure of the high-pressure brine after the reverse osmosis membrane reaches as high as 5.8–6.0 MPa. Therefore, utilizing the pressure energy of this high-pressure fluid becomes a crucial step in reducing the energy consumption of reverse osmosis seawater desalination technology. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a self-driven rotary pressure energy recovery device with a built-in guide impeller structure that is simple in structure, requires no external power, reduces failure rate and maintenance cost, and can better adapt to flow changes.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a self-driven rotary pressure energy recovery device with a built-in guide impeller structure, comprising an outer sleeve, an upper end cover, a lower end cover, and a rotor. The rotor is coaxially and rotatably installed inside the outer sleeve, with a clearance fit between the rotor and the outer sleeve. The upper end cover is sealed to one end of the outer sleeve, and the lower end cover is sealed to the other end of the outer sleeve. An upper impeller is coaxially driven to one end of the rotor, and a lower impeller is coaxially driven to the other end of the rotor. Both the blade tips of the upper impeller and the blade tips of the lower impeller have gaps between them and the inner wall surface of the sleeve. The blades of the upper impeller have gaps with the inner wall of the upper end cover, and the blades of the lower impeller have gaps with the inner wall of the lower end cover. A transducer channel is provided inside the rotor; one end of the transducer channel is connected to the upper impeller, and the other end is connected to the lower impeller. A high-pressure fluid inlet and a low-pressure fluid outlet are connected to the upper end cover, and a high-pressure fluid outlet and a low-pressure fluid inlet are connected to the lower end cover. High-pressure waste liquid enters the outer sleeve through the high-pressure fluid inlet, driving the upper impeller to rotate; low-pressure seawater enters the outer sleeve through the low-pressure fluid inlet, driving the lower impeller to rotate. The upper and lower impellers synchronously drive the rotor to rotate.

[0006] The aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure has a first liquid storage chamber formed between two adjacent blades of the upper impeller and a second liquid storage chamber formed between two adjacent blades of the lower impeller. The two ends of the transducer flow channel are respectively fluidly connected to the first liquid storage chamber and the second liquid storage chamber. When the rotor rotates: one of the first liquid storage chambers is fluidly connected to the high-pressure fluid inlet and the low-pressure fluid outlet in sequence, and one of the second liquid storage chambers is fluidly connected to the high-pressure fluid outlet and the low-pressure fluid inlet in sequence.

[0007] In the aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure, the energy transducer is arranged along the axial direction of the rotor and extends through both ends of the rotor. The high-pressure fluid inlet and the high-pressure fluid outlet are axially corresponding to each other, and the low-pressure fluid outlet and the low-pressure fluid inlet are axially corresponding to each other.

[0008] The aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure has two or more transducer channels equally spaced along its circumference inside the rotor, and any one of the first liquid storage chambers is fluidly connected to the second liquid storage chamber through at least one transducer channel.

[0009] In the aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure, a partition is formed between two adjacent energy transducer channels. The blade thickness of the upper impeller or the lower impeller is equal to the thickness of the partition, and the blades of the upper impeller or the lower impeller are connected to the partition.

[0010] The self-driven rotary pressure energy recovery device with a built-in guide impeller structure has a transducer channel length of 220 mm and upper and lower impeller lengths of 40 mm.

[0011] The aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure has an upper impeller and a lower impeller with identical structures and are arranged in a mirror-symmetrical manner about a cross-section perpendicular to the rotor axis.

[0012] In the aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure, the angle between the upper impeller blade and the rotor axis is 45 to 80 degrees, and the angle between the lower impeller and the rotor axis is also 45 to 80 degrees.

[0013] In the aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure, the inner diameters of the high-pressure fluid inlet, the low-pressure fluid outlet, the high-pressure fluid outlet, and the low-pressure fluid inlet are the same, and all are greater than the maximum distance between two adjacent blades of the upper impeller or the lower impeller.

[0014] The aforementioned self-driven rotary pressure energy recovery device with a built-in guide impeller structure includes a lubrication gap formed between the outer circumferential surface of the rotor and the inner circumferential surface of the outer sleeve. A lubrication groove is formed along the circumferential direction on the middle of the outer circumferential surface of the rotor, and the lubrication gap is in fluid communication with the lubrication groove. A drain hole is formed through the side wall of the outer sleeve at a position corresponding to the lubrication groove, and the drain hole is in fluid communication with the lubrication groove. The length of the lubrication groove is 50 mm, and the diameter of the drain hole is 10 mm. During rotor operation, the working fluid fills the lubrication groove, providing hydraulic lubrication and preventing damaging friction between the rotor and the rotor sleeve during operation. A pressure equalization groove is formed along the circumferential direction on the side of the upper end cover that contacts the end of the outer sleeve. A portion of the equalizing groove is located between the end face of the upper end cover and the outer sleeve, and the other portion of the equalizing groove is in fluid communication with the outer sleeve. Another equalizing groove is formed along the circumference of the side of the lower end cover that contacts the end of the outer sleeve. A portion of this other equalizing groove is located between the end face of the lower end cover and the outer sleeve, and the other portion of this other equalizing groove is in fluid communication with the outer sleeve. The equalizing groove has a depth of 2 mm and a width of 1.5 mm. By setting the equalizing groove, the system pressure is balanced under high-speed rotor rotation, reducing fluid resistance loss and pressure fluctuations generated during flow. A central shaft is coaxially fixedly connected inside the rotor. One end of the central shaft is rotatably connected to the upper end cover, and the other end of the central shaft is rotatably connected to the lower end cover.

[0015] The technical solution of the present invention achieves the following beneficial technical effects:

[0016] 1. In this invention, by using a rotor with an internal impeller structure, high and low pressure fluids flow into the impeller through the inlet and impact it. The fluid velocity is converted into tangential velocity, which drives the rotor to rotate and provides kinetic energy for the rotor rotation. This enables the rotor to be self-driven and achieve stable rotation speed. Therefore, no additional kinetic energy is required for the device, which improves the stability and reliability of the entire system and enables the device to operate under a wider range of conditions.

[0017] 2. In this invention, the rotor start-up process is completed by fluid self-drive, and the rotor speed can be adjusted by controlling the impeller tilt angle through the matching relationship between flow rate and rotation speed. This design can better adapt to changing pressure and flow conditions under different working conditions, maintain efficient operation and ensure stable pressurized water supply.

[0018] 3. In this invention, through the integrated design of the rotor and impeller structure and the modular design of the device, the structure is simple, the operability is good, the convenience is good, the service life is long and the maintenance requirements are low, thus reducing the complexity and cost of operation. Attached Figure Description

[0019] Figure 1 A front view of the structure of the present invention;

[0020] Figure 2 Top view of the structure of the present invention;

[0021] Figure 3 This invention Figure 2 Schematic diagram of the cross section at point AA;

[0022] Figure 4 This invention Figure 2 Schematic diagram of the cross section at BB;

[0023] Figure 5 A schematic diagram of the upper and lower impellers of the present invention mounted on the rotor;

[0024] Figure 6 A three-dimensional cross-sectional structural diagram of the present invention;

[0025] Figure 7 A three-dimensional structural schematic diagram of the rotor of this invention;

[0026] Figure 8 A partial cross-sectional schematic diagram of the upper and lower impellers of the present invention mounted on the rotor;

[0027] Figure 9 A partial schematic diagram of the connection between the upper and lower impellers and the partition layer in this invention;

[0028] Figure 10 A partial schematic diagram of the pressure equalization groove of the present invention.

[0029] The reference numerals in the figure are as follows: 1-outer sleeve; 2-upper end cover; 21-high pressure fluid inlet; 22-low pressure fluid outlet; 3-lower end cover; 31-high pressure fluid outlet; 32-low pressure fluid inlet; 4-rotor; 5-central shaft; 6-upper impeller; 7-lower impeller; 8-transducer channel; 9-pressure equalization tank; 10-lubrication tank; 11-drain hole; 12-first liquid storage chamber; 13-second liquid storage chamber; 14-partition. Detailed Implementation

[0030] This embodiment describes a self-driven rotary pressure energy recovery device with a built-in guide impeller structure, such as... Figure 1 , Figure 3As shown, the device includes an outer sleeve 1, an upper end cover 2, a lower end cover 3, and a rotor 4. The rotor 4 is coaxially and rotatably mounted inside the outer sleeve 1. A central shaft 5 is coaxially and fixedly connected inside the rotor 4. One end of the central shaft 5 is rotatably connected to the upper end cover 2, and the other end of the central shaft 5 is rotatably connected to the lower end cover 3. The rotor 4 and the outer sleeve 1 are clearance-fitted. The upper end cover 2 is sealed to one end of the outer sleeve 1, and the lower end cover 3 is sealed to the other end of the outer sleeve 1. At one end of the rotor 4, an upper impeller 6 is coaxially connected to it, and a lower impeller 7 is coaxially connected to it. Both the blade ends of the upper impeller 6 and the blade ends of the lower impeller 7 have gaps between them and the inner wall of the sleeve 1. The blades of the upper impeller 6 have gaps between them and the inner wall of the upper end cover 2, and the blades of the lower impeller 7 have gaps between them and the inner wall of the lower end cover 3. This arrangement ensures that the rotor 4, upper impeller 6, and lower impeller 7 can rotate normally. The smaller the gaps mentioned above, the better. A transducer channel 8 is provided inside the rotor 4. One end of the transducer channel 8 is connected to the upper impeller 6, and the other end is connected to the lower impeller 7. A high-pressure fluid inlet 21 and a low-pressure fluid outlet 22 are connected to the upper end cover 2, and a high-pressure fluid outlet 31 and a low-pressure fluid inlet 32 ​​are connected to the lower end cover 3. High-pressure waste liquid enters the outer sleeve 1 through the high-pressure fluid inlet 21, driving the upper impeller 6 to rotate. Low-pressure seawater enters the outer sleeve 1 through the low-pressure fluid inlet 32, driving the lower impeller 7 to rotate. The upper impeller 6 and the lower impeller 7 synchronously drive the rotor 4 to rotate. Through the rotor's built-in impeller structure, high and low-pressure fluids flow into the impeller through the inlet, impacting it. The fluid velocity is converted into tangential velocity, driving the rotor to rotate and providing kinetic energy for its rotation. This achieves rotor self-drive and stable rotation speed, thus eliminating the need for additional kinetic energy supply to the device, improving the stability and reliability of the entire system, and enabling the device to operate under a wider range of conditions.

[0031] like Figure 3 , Figure 5 As shown, a first liquid storage chamber 12 is formed between two adjacent blades of the upper impeller 6, and a second liquid storage chamber 13 is formed between two adjacent blades of the lower impeller 7. The two ends of the transducer channel 8 are respectively fluidly connected to the first liquid storage chamber 12 and the second liquid storage chamber 13. When the rotor 4 rotates: one of the first liquid storage chambers 12 is fluidly connected to the high-pressure fluid inlet 21 and the low-pressure fluid outlet 22 in sequence, and one of the second liquid storage chambers 13 is fluidly connected to the high-pressure fluid outlet 31 and the low-pressure fluid inlet 32 ​​in sequence.

[0032] like Figure 3As shown, the transducer channel 8 is arranged along the axial direction of the rotor 4 and extends through both ends of the rotor 4. The high-pressure fluid inlet 21 and the high-pressure fluid outlet 31 correspond to each other in the axial direction, and the low-pressure fluid outlet 22 and the low-pressure fluid inlet 32 ​​correspond to each other in the axial direction.

[0033] like Figure 5 , Figure 7 As shown, the rotor 4 has 16 and transducer channels 8 evenly spaced along its circumference. Any one of the first liquid storage chambers 12 is fluidly connected to the second liquid storage chamber 13 through the two transducer channels 8.

[0034] like Figure 7 , Figure 8 , Figure 9 As shown, a partition 14 is formed between two adjacent transducer channels 8. The blade thickness of the upper impeller 6 or the lower impeller 7 is equal to the thickness of the partition 14, and the blade of the upper impeller 6 or the lower impeller 7 is connected to the partition 14. The length of the transducer channel 8 is 220 mm, and the lengths of the upper impeller 6 and the lower impeller 7 are 40 mm.

[0035] like Figure 5 As shown, the upper impeller 6 and the lower impeller 7 have the same structure and are arranged in a mirror symmetrical manner about a cross-section perpendicular to the axis of the rotor 4. The angle between the blades of the upper impeller 6 and the axis of the rotor 4 is 45 to 80 degrees, and the angle between the lower impeller 7 and the axis of the rotor 4 is also 45 to 80 degrees.

[0036] like Figure 1 , Figure 2 As shown, the inner diameters of the high-pressure fluid inlet 21, the low-pressure fluid outlet 22, the high-pressure fluid outlet 31, and the low-pressure fluid inlet 32 ​​are the same, and all are greater than the maximum distance between two adjacent blades of the upper impeller 6 or the lower impeller 7.

[0037] like Figure 3 , 4 As shown in Figure 5, the gap between the outer circumferential surface of the rotor 4 and the inner circumferential surface of the outer sleeve 1 forms a lubrication gap. A lubrication groove 10 is formed along its circumferential direction in the middle of the outer circumferential surface of the rotor 4. The lubrication gap and the lubrication groove 10 are in fluid communication. A drain hole 11 is formed through the side wall of the outer sleeve 1 at a position corresponding to the lubrication groove 10. The drain hole 11 is in fluid communication with the lubrication groove 10. The length of the lubrication groove 10 is 50 mm, and the diameter of the drain hole 11 is 10 mm.

[0038] like Figure 10As shown, a pressure equalization groove 9 is formed along the circumference of the side of the upper end cover 2 that contacts the end of the outer sleeve 1. A portion of the pressure equalization groove 9 is located between the end faces of the upper end cover 2 and the outer sleeve 1, and the other portion of the pressure equalization groove 9 is in fluid communication with the outer sleeve 1. Another pressure equalization groove 9 is formed along the circumference of the side of the lower end cover 3 that contacts the end of the outer sleeve 1. A portion of the other pressure equalization groove 9 is located between the end faces of the lower end cover 3 and the outer sleeve 1, and the other portion of the other pressure equalization groove 9 is in fluid communication with the outer sleeve 1. The depth of the pressure equalization groove 9 is 2 mm and the width is 1.5 mm.

[0039] The working principle of this invention: The main function of this invention is to use the residual pressure of the high-pressure brine after the reverse osmosis membrane in the reverse osmosis seawater desalination process to pressurize the seawater feedstock, thereby providing pressurized seawater feedstock for seawater desalination and realizing pressure energy recovery.

[0040] At work, such as Figure 3 , Figure 6 As shown, the high-pressure fluid inlet 21 is connected to the high-pressure wastewater, and the low-pressure fluid inlet 32 ​​is connected to the low-pressure seawater feedstock. The specific decomposition steps are as follows:

[0041] Step 1: High-pressure wastewater enters the outer sleeve 1 through the high-pressure fluid inlet 21 and drives the upper impeller 6 to rotate before entering the first transducer channel 8. The upper impeller 6 drives the rotor 4 and the lower impeller 7 to rotate synchronously. The second liquid storage chamber 13 on the lower impeller 7, the first transducer channel 8, and the first liquid storage chamber 12 of the upper impeller 6, which are filled with wastewater, rotate at a certain angle and are offset from the high-pressure fluid inlet 21 and the high-pressure fluid outlet 31 at a certain angle. At this time, the first liquid storage chamber 12, together with the inner wall of the upper end cover 2 and the inner wall of the outer sleeve 1, forms a closed space a1. The second liquid storage chamber 13, together with the inner wall of the lower end cover 3 and the inner wall of the outer sleeve 1, forms a closed space a2. The two closed spaces a1 and a2 and the first transducer channel 8 together form a first large closed space A1 for storing wastewater.

[0042] Step 2: Low-pressure seawater enters from the low-pressure fluid inlet 32 ​​and enters another second liquid storage chamber 13 on the lower impeller 7, then enters the second transducer channel 8, and finally enters the first liquid storage chamber 12 in the upper impeller 6. At the same time, when the low-pressure seawater passes through the lower impeller 7, it drives the lower impeller 7 to rotate. Other principles are the same as those described above, and a second large closed space A2 containing low-pressure seawater is formed.

[0043] Step 3: Liquid energy conversion process: When the large enclosed space A2 containing low-pressure seawater rotates to the position of high-pressure fluid inlet 21, it is connected to the high-pressure fluid inlet 21. High-pressure wastewater enters through the high-pressure fluid inlet 21 and pushes and squeezes the original low-pressure seawater to be discharged outward through the high-pressure fluid outlet 31, thereby increasing the pressure of the low-pressure seawater and realizing pressure energy recovery. At this time, the low-pressure seawater in the large enclosed space A2 is replaced by wastewater. As the rotor 4 continues to rotate, when the low-pressure seawater enters the energy conversion channel 8 through the low-pressure fluid inlet 32, it pushes the wastewater out of the low-pressure fluid outlet 22.

[0044] In actual operation, the above process is fast and continuous; the breakdown is only for the purpose of understanding the operating principle and process.

[0045] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A self-driven rotary pressure energy recovery device with a built-in guide impeller structure, characterized in that, The device includes an outer sleeve (1), an upper end cover (2), a lower end cover (3), and a rotor (4). The rotor (4) is coaxially rotatably installed inside the outer sleeve (1). The rotor (4) is clearance-fitted with the outer sleeve (1). The upper end cover (2) is sealed to one end of the outer sleeve (1), and the lower end cover (3) is sealed to the other end of the outer sleeve (1). An upper impeller (6) is coaxially driven to one end of the rotor (4), and a lower impeller (7) is coaxially driven to the other end of the rotor (4). The blade ends of the upper impeller (6) and the blade ends of the lower impeller (7) have gaps between them and the inner wall of the sleeve (1). The blades of the upper impeller (6) have gaps between them and the inner wall of the upper end cover (2). The lower impeller... (7) The blades have gaps with the inner wall of the lower end cover (3); the rotor (4) has a transducer channel (8) inside, one end of the transducer channel (8) is connected to the upper impeller (6), and the other end of the transducer channel (8) is connected to the lower impeller (7). The upper end cover (2) is connected to a high-pressure fluid inlet (21) and a low-pressure fluid outlet (22), and the lower end cover (3) is connected to a high-pressure fluid outlet (31) and a low-pressure fluid inlet (32). High-pressure waste liquid enters the outer sleeve (1) through the high-pressure fluid inlet (21) and drives the upper impeller (6) to rotate. Low-pressure seawater enters the outer sleeve (1) through the low-pressure fluid inlet (32) and drives the lower impeller (7) to rotate. The upper impeller (6) and the lower impeller (7) drive the rotor (4) to rotate synchronously. The upper impeller (6) forms a first liquid storage chamber (12) between two adjacent blades, and the lower impeller (7) forms a second liquid storage chamber (13) between two adjacent blades. The two ends of the transducer channel (8) are respectively fluidly connected to the first liquid storage chamber (12) and the second liquid storage chamber (13). When the rotor (4) rotates: one of the first liquid storage chambers (12) is fluidly connected to the high-pressure fluid inlet (21) and the low-pressure fluid outlet (22) in sequence, and one of the second liquid storage chambers (13) is fluidly connected to the high-pressure fluid outlet (31) and the low-pressure fluid inlet (32) in sequence.

2. The self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 1, characterized in that, The transducer channel (8) is arranged along the axial direction of the rotor (4) and extends through both ends of the rotor (4). The high-pressure fluid inlet (21) and the high-pressure fluid outlet (31) correspond to each other in the axial direction. The low-pressure fluid outlet (22) and the low-pressure fluid inlet (32) correspond to each other in the axial direction.

3. The self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 2, characterized in that, The rotor (4) has two or more transducer channels (8) at equal intervals along its circumference. Each of the first liquid storage chambers (12) is in fluid communication with the second liquid storage chamber (13) through at least one transducer channel (8).

4. The self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 3, characterized in that, A partition (14) is formed between two adjacent transducer channels (8), the blade thickness of the upper impeller (6) or the lower impeller (7) is equal to the thickness of the partition (14), and the blades of the upper impeller (6) or the lower impeller (7) are connected to the partition (14).

5. A self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 4, characterized in that, The length of the transducer channel (8) is 220 mm, and the lengths of the upper impeller (6) and the lower impeller (7) are 40 mm.

6. A self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to any one of claims 1-5, characterized in that, The upper impeller (6) and the lower impeller (7) have the same structure and are arranged in a mirror symmetrical manner about a cross section perpendicular to the axis of the rotor (4).

7. A self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 6, characterized in that, The angle between the blades of the upper impeller (6) and the axis of the rotor (4) is 45-80 degrees, and the angle between the lower impeller (7) and the axis of the rotor (4) is also 45-80 degrees.

8. A self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 6, characterized in that, The inner diameters of the high-pressure fluid inlet (21), the low-pressure fluid outlet (22), the high-pressure fluid outlet (31), and the low-pressure fluid inlet (32) are the same and are all greater than the maximum distance between two adjacent blades of the upper impeller (6) or the lower impeller (7).

9. A self-driven rotary pressure energy recovery device with a built-in guide impeller structure according to claim 1, characterized in that, The gap between the outer circumferential surface of the rotor (4) and the inner circumferential surface of the outer sleeve (1) forms a lubrication gap. A lubrication groove (10) is formed on the middle part of the outer circumferential surface of the rotor (4) along its circumferential direction. The lubrication gap and the lubrication groove (10) are in fluid communication. A drain hole (11) is formed through the side wall of the outer sleeve (1) at a position corresponding to the lubrication groove (10). The drain hole (11) is in fluid communication with the lubrication groove (10). The length of the lubrication groove (10) is 50 mm, and the diameter of the drain hole (11) is 10 mm. A pressure equalization groove (9) is formed on the side of the upper end cover (2) that contacts the end of the outer sleeve (1) along its circumferential direction. A part of the pressure equalization groove (9) is located on the upper end cover (2). Between the end face of the outer sleeve (1) and the other part of the pressure equalization groove (9) is in fluid communication with the outer sleeve (1); another pressure equalization groove (9) is provided on the side of the lower end cover (3) that contacts the end of the outer sleeve (1) along its circumferential direction, a part of the other pressure equalization groove (9) is located between the end face of the lower end cover (3) and the outer sleeve (1), and the other part of the other pressure equalization groove (9) is in fluid communication with the outer sleeve (1); the depth of the pressure equalization groove (9) is 2mm and the width is 1.5mm; a central shaft (5) is coaxially fixedly connected inside the rotor (4), one end of the central shaft (5) is rotatably connected to the upper end cover (2), and the other end of the central shaft (5) is rotatably connected to the lower end cover (3).

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