Reverse circulation volumetric canned motor pump

Abstract

The invention relates to the technical field of shielding pumps, and particularly discloses a reverse circulation positive displacement shielding electric pump which comprises a pump device, the pump device comprises a pump stator, a pump rotor and a sliding piece, a pump cavity is formed in the pump stator, the pump rotor is eccentrically and rotationally arranged in the pump cavity, a plurality of sliding grooves are formed in the side wall of the pump rotor, and the sliding piece is arranged in the pump cavity. The sliding piece is connected into the sliding groove in a sliding mode, and the other end of the sliding piece is used for abutting against the inner wall of the pump stator. The motor device comprises a motor body, a motor stator and a motor rotor, the motor stator and the motor rotor are arranged in the motor body, the motor stator is fixedly arranged in the motor body, and the motor rotor and the pump rotor are coaxially and fixedly connected, so that after the motor stator is powered on, the motor stator is driven to rotate; and the motor rotor rotates under electromagnetic induction and drives the pump rotor to rotate. The sliding vane pump is adopted as a pumping unit, the self-suction capacity and the cavitation resistance are high, and the pump is more suitable for conveying media easy to vaporize.

Description

Technical Field

[0001] This application relates to the field of canned pump technology, and in particular to a reverse circulation positive displacement canned electric pump. Background Technology

[0002] Reverse circulation positive displacement canned motor pumps are mainly used for conveying easily vaporized liquids and unloading tanks. They are used to transport flammable, explosive, toxic, and volatile liquids such as liquid ammonia, liquefied petroleum gas, chloromethane, dimethyl ether, and isobutylene. They are widely used in ammonia production, gas, petroleum, chemical, pharmaceutical, and new materials industries.

[0003] Most existing canned motor pumps are centrifugal pumps, which use rotating impellers to transport liquids. During the unloading process of tanks carrying easily vaporized liquids, cavitation can easily occur as the inlet liquid level decreases. When cavitation occurs, a large number of air bubbles occupy the flow channel space, changing the effective shape of the flow channel and disrupting the continuity of liquid flow. This prevents the impeller from effectively transferring energy to the liquid, causing a sharp drop in the pump's head, flow rate, and efficiency. Consequently, the pump's output end cannot discharge liquid, affecting the normal operation of the pump. Summary of the Invention

[0004] To mitigate the adverse effects of cavitation on canned motor pumps, this application provides a reverse circulation positive displacement canned motor pump.

[0005] The reverse circulation positive displacement shielded electric pump provided in this application adopts the following technical solution:

[0006] A reverse circulation positive displacement shielded electric pump includes a pump assembly, which is a vane pump. The pump assembly includes a pump body, a pump stator, a pump rotor, and vanes. The pump stator is disposed in the pump body and has a pump chamber inside. The pump rotor is eccentrically rotatably disposed in the pump chamber. Multiple sliding grooves are spaced apart on the side wall of the pump rotor. One end of the vane is slidably connected to the pump rotor and disposed in the sliding groove, and the other end of the vane is used to abut against the inner wall of the pump stator.

[0007] The motor device includes a motor body, a motor stator and a motor rotor disposed in the motor body. The motor stator is fixedly disposed in the motor body, and the motor rotor is coaxially and fixedly connected to the pump rotor, so that when the motor stator is energized, the motor rotor rotates under electromagnetic induction and drives the pump rotor to rotate.

[0008] By adopting the above technical solutions, the vane pump, due to its positive displacement working principle, achieves stable and mechanical liquid transportation. The suction process of the vane pump is gentler, the pressure drop is gradual, and it is less likely to generate bubbles. Moreover, the vane pump can better accommodate and expel the air bubbles that have been sucked in, while the gas in the centrifugal pump will directly disrupt the liquid suction process. Therefore, it avoids the core problem of the centrifugal pump generating violent eddies and local extremely low pressure at the suction end due to kinetic energy conversion, and is less prone to cavitation, thus ensuring the smooth transportation of liquid.

[0009] Optionally, the motor stator has a rotor cavity coaxially formed inside for accommodating the motor rotor, the rotor cavity is connected to the pump cavity, and a drain port connected to the rotor cavity is formed at the end of the motor stator away from the pump device; a shielding sleeve is also provided inside the motor body, and the motor stator is located between the motor body and the shielding sleeve.

[0010] By adopting the above technical solution, the pump eliminates the mechanical seal device and combines the pump unit and motor unit into a sealed container filled with the transported liquid using a static seal, thus eliminating leakage problems. The pumping medium can flow into the rotor cavity to lubricate and cool the motor rotor, and then be discharged through the drain port. In this way, the flowing transport medium achieves heat dissipation for the motor unit. While ensuring sealing, it can also ensure the heat dissipation effect of the motor unit, thereby enabling the device to operate normally and avoiding damage caused by excessive temperature.

[0011] Optionally, a coolant jacket for circulating coolant is provided on the outer wall of the motor body.

[0012] By adopting the above technical solution, external coolant can be introduced into the coolant jacket to provide auxiliary cooling for the motor, further improving the heat dissipation effect and ensuring stable operation of the motor in high-temperature environments.

[0013] Optionally, the slide includes a support block, a sliding block, and a spring. One end of the sliding block is used to abut against the inner wall of the pump stator, and the other end of the sliding block has a receiving groove for accommodating the support block. One end of the support block abuts against the bottom wall of the groove, and the other end of the support block is slidably disposed in the receiving groove. The spring is connected between the support block and the sliding block. The spring causes the sliding block to tend to slide away from the support block, and causes the end of the sliding block to abut against the inner wall of the pump stator.

[0014] By adopting the above technical solution, the spring provides preload, ensuring that the sliding block always remains in contact with the inner wall of the stator. This guarantees the sealing effect during startup and when the pump rotor is at low speed, preventing liquid leakage between adjacent sealing cavities and thus ensuring the pump's working efficiency. When the pump rotor speed is high, the combined effect of the centrifugal force on the sliding block and the spring preload makes the sliding block press against the inner wall of the pump stator, ensuring the sealing effect. The sliding vane adopts a split structure, preventing the spring from directly contacting the conveyed liquid, avoiding the possibility of the spring being corroded by the conveyed liquid, and helping to extend its service life.

[0015] Optionally, the end of the sliding block away from the support block is arc-shaped.

[0016] By adopting the above technical solution, the arc-shaped design ensures uniform and stable surface contact between the end of the vane and the inner wall of the pump stator, thereby forming an effective sealing zone. This helps reduce the leakage of liquid from the discharge chamber to the suction chamber through the gap at the end of the vane, thus improving the pump's volumetric efficiency and output pressure. The arc-shaped design also reduces the contact stress between the sliding block and the inner wall of the pump stator, reducing wear and helping to extend the service life of the vane.

[0017] Optionally, a guide rod is fixedly provided on the inner wall of the sliding block. The guide rod is located in the receiving groove. A guide hole is provided on the support block. One end of the guide rod is slidably disposed in the guide hole. The spring is located in the guide hole and is connected between the end of the guide rod and the bottom wall of the guide hole.

[0018] By adopting the above technical solution, the cooperation between the guide rod and the guide hole can guide the sliding of the sliding block, thereby ensuring the stability of the sliding process of the sliding block; the spring is located in the guide hole, which further reduces the possibility of the spring coming into contact with the conveyed liquid, thereby reducing the possibility of the spring being corroded.

[0019] Optionally, the support block is slidably disposed in the groove so that when the sliding block abuts against the inner wall of the pump stator, the support block can slide into the receiving groove under the action of centrifugal force.

[0020] By adopting the above technical solution, when the pump rotor speed is relatively slow, the spring causes the sliding block to press against the inner wall of the pump stator and the support block to press against the bottom wall of the sliding groove. At this time, the preload of the spring plays a dominant role, ensuring the sealing between the end of the sliding block and the pump stator. When the pump rotor speed increases, the centrifugal force on the sliding block increases, further enhancing the sealing between the end of the sliding block and the pump stator. In addition, the support block will also slide outward under the action of centrifugal force, causing the spring to be further compressed, thereby applying a greater preload to the sliding block, which helps to enhance the sealing. When the support block slides completely into the receiving groove, the support block and the sliding block form a whole. This whole is heavier and therefore experiences a greater centrifugal force. At this time, the centrifugal force plays a dominant role, thus ensuring the sealing between the sliding block and the pump stator even when the pump rotor speed is relatively fast, reducing leakage between the discharge chamber and the suction chamber, thereby ensuring the working efficiency of the pump.

[0021] In this design, the support block can slide outward as the pump rotor speed increases, thereby increasing the centrifugal force on the vane. Therefore, when the pump rotor speed is low, the preload of the spring can ensure the seal, and it can also prevent the vane from applying excessive pressure to the pump stator, thus reducing wear. When the pump rotor speed is high, it can adaptively increase the pressure applied by the vane to the pump stator, thereby ensuring the seal. Therefore, the split vane structure can take into account both low-speed wear and high-speed sealing insufficiency, making it more practical.

[0022] Optionally, flexible pads are provided on the bottom wall of the receiving groove and at one end of the support block located in the receiving groove, and the flexible pads on the bottom wall of the receiving groove and the flexible pads at the end of the support block are used to abut against each other.

[0023] By adopting the above technical solution, the flexible pad can buffer the impact and vibration between the support block and the sliding block, reduce noise, and improve the smoothness of operation.

[0024] Optionally, the sliding block is provided with an oil drain hole, one end of which is connected to the receiving groove, and the other end of which is connected to the pump chamber.

[0025] By adopting the above technical solution, the oil drain hole can keep the liquid pressure in the receiving tank balanced with the liquid pressure in the pump chamber, avoiding the formation of a closed high-pressure chamber inside the receiving tank, thus allowing the sliding block to slide smoothly. During the operation of the pump device, the sliding block and the support block will intermittently move closer and further away from each other, allowing the liquid in the pump chamber to enter the receiving tank through the oil drain hole, and then the liquid in the receiving tank will be discharged into the pump chamber through the oil drain hole. Therefore, the liquid in the receiving tank can play a role in heat dissipation and lubrication, avoiding excessive internal structural temperature and jamming.

[0026] Optionally, the support block is provided with a balance hole, one end of which is connected to the receiving groove and the other end of which is connected to the sliding groove.

[0027] By adopting the above technical solution, the balance hole further ensures the balance of internal pressure of the slide, ensures the smooth sliding of the support block, and improves the slide's response to changes in rotational speed and pressure.

[0028] In summary, this application includes the following beneficial technical effects:

[0029] 1. Using a sliding vane pump as the pumping unit, it has strong self-priming ability and anti-cavitation performance, making it more suitable for conveying easily vaporized media. It also has uniform output flow, stable operation, and low noise, effectively solving the problem of cavitation that easily occurs when centrifugal pumps are unloading at low liquid levels.

[0030] 2. The motor and pump adopt an integrated shielded design, forming a sealed container filled with the pumped liquid using a static sealing method, thus eliminating leakage problems. The pumped medium can circulate through the inside of the motor to cool and lubricate the motor rotor. At the same time, a coolant jacket is provided on the outside of the motor body. The dual cooling system ensures the long-term reliable operation of the motor under harsh working conditions.

[0031] 3. The sliding vane adopts a split structure design. This structure adaptively adjusts the contact force between the sliding vane and the inner wall of the stator through the synergistic effect of centrifugal force and spring preload. In the pump start-up state and when the pump rotor speed is low, the sliding block is pressed against the inner wall of the pump stator by the spring. At this time, the weight of the sliding block is relatively light, so the pressing effect can be guaranteed with a lower elastic force, which can reduce wear. As the pump rotor speed increases, the support block can gradually slide into the receiving groove inside the sliding block under the action of centrifugal force, thereby increasing the spring preload and the overall centrifugal force. At this time, the contact force increases, which can guarantee the pressing effect and thus ensure sealing. Therefore, this solution can solve the contradiction of high wear at low speed and insufficient sealing at high speed.

[0032] 4. By setting oil drain holes and balance holes on the sliding block and support block, the risk of high-pressure oil circuit blockage is avoided. The structure is simple and reliable, and it can significantly improve the maximum operating speed and pressure limit of the pump without relying on a complex hydraulic system, thus broadening the application range of the pump. Attached Figure Description

[0033] Figure 1 This is a cross-sectional view of Embodiment 1 of this application;

[0034] Figure 2 This is a structural schematic diagram of Embodiment 1 of this application, used to illustrate the positions of the inlet pipe and the outlet pipe;

[0035] Figure 3This is a cross-sectional view of Embodiment 1 of this application used to illustrate the installation position of the slider;

[0036] Figure 4 This is a cross-sectional view of Embodiment 2 of this application, used to illustrate the installation position of the slider;

[0037] Figure 5 yes Figure 4 A cross-sectional view along the direction aa;

[0038] Figure 6 This is a cross-sectional view of Embodiment 3 of this application used to show the location of the drain hole and the balance hole.

[0039] Reference numerals: 1. Pump assembly; 11. Pump body; 111. Inlet pipe; 112. Outlet pipe; 12. Pump stator; 121. Pump chamber; 13. Pump rotor; 131. Sliding groove; 14. Sliding vane; 141. Support block; 1411. Guide hole; 1412. Balance hole; 142. Sliding block; 1421. Receiving groove; 1422. Oil drain hole; 143. Spring; 15. Baffle; 2. Motor assembly; 21. Motor body; 211. Motor housing; 212. Front flange; 213. Rear flange; 22. Motor stator; 221. Rotor cavity; 222. Drain port; 23. Motor rotor; 24. Shielding sleeve; 25. Coolant jacket; 3. Guide rod. Detailed Implementation

[0040] The following combination Figures 1-6 This application will be described in further detail.

[0041] Example 1

[0042] This application discloses a reverse circulation positive displacement shielded electric pump. (Refer to...) Figure 1 The reverse circulation positive displacement canned electric pump includes a pump unit 1 and a motor unit 2 connected to one end of the pump unit 1.

[0043] Reference Figure 1 and Figure 2 Pump assembly 1 is a vane pump, comprising a pump body 11, a pump stator 12, a pump rotor 13, and vanes 14. An inlet pipe 111 and an outlet pipe 112 are fixedly mounted on the pump body 11, both communicating with the interior of the pump body 11. The inlet pipe 111 is the input end of the pump body 11, which is in the low-pressure zone; the outlet pipe 112 is the output end of the pump body 11, which is in the high-pressure zone. The pump stator 12 is fixedly installed inside the pump body 11, and a through-hole is formed on the pump stator 12. Baffles 15 are provided on both sides of the pump stator 12 inside the pump body 11, and a cylindrical pump chamber 121 is formed between the inner wall of the through-hole of the pump stator 12 and the baffles 15 on both sides.

[0044] Reference Figure 3The pump rotor 13 is arranged in a disc shape and is eccentrically mounted in the pump chamber 121. The pump rotor 13 can be driven to rotate by the motor device 2. Multiple sliding grooves 131 are evenly spaced circumferentially on the circumferential sidewall of the pump rotor 13, and the depth of the grooves 131 is arranged radially along the pump rotor 13. A sliding vane 14 is slidably mounted in each groove 131, with one end of the vane 14 away from the groove 131 located in the pump chamber 121 and abutting against the inner wall of the pump stator 12.

[0045] Multiple sealing cavities with periodically changing volumes can be formed between the inner curved surface of the pump stator 12, the outer surface of the pump rotor 13, the sliding vane 14 that slides in the sliding groove 131 by centrifugal force, and the baffles 15 on both sides of the pump rotor 13. As the pump rotor 13 rotates, the volume of the sealing cavity on the side closer to the low-pressure area gradually increases, and a negative pressure is generated to draw the conveying medium from the low-pressure area. When the pump rotor 13 rotates at a certain angle, the volume of the sealing cavity will gradually decrease, thereby squeezing the conveying medium out of the high-pressure area. The pump rotor 13 completes one cycle from suction to discharge for each rotation.

[0046] Reference Figure 1 The motor unit 2 includes a motor body 21, a motor stator 22, and a motor rotor 23. The motor body 21 includes a motor housing 211, a front flange 212, and a rear flange 213, which are fixedly connected to both ends of the motor housing 211. A shielding sleeve 24 is also fixedly installed inside the motor housing 211, with its outer wall spaced apart from the inner wall of the motor housing 211. Both ends of the shielding sleeve 24 are fixedly connected to the front flange 212 and the rear flange 213, respectively. The motor stator 22 includes stator windings, which are fixedly installed in the gap between the motor housing 211 and the shielding sleeve 24. The motor rotor 23 is located inside the shielding sleeve 24 and is rotatably disposed inside the motor housing 211. The motor rotor 23 is coaxially fixedly connected to the pump rotor 13 via a connecting shaft. Therefore, when the stator windings are energized, the motor rotor 23 rotates under electromagnetic induction, driving the pump rotor 13 to rotate, thereby realizing the transportation of liquid.

[0047] The motor stator 22 has a coaxial rotor cavity 221 inside, which houses the motor rotor 23. A drain port 222 is located at the end of the motor stator 22 furthest from the pump unit 1; one end of the rotor cavity 221 communicates with the drain port 222, and the other end communicates with the pump chamber 121. Therefore, some of the pumped medium can enter the rotor cavity 221 to cool and lubricate the motor rotor 23 before being discharged from the drain port 222, achieving reverse circulation.

[0048] "Reverse circulation" refers to a circulation method in which a small portion of the high-pressure liquid pumped out does not flow directly to the outlet, but is guided back and flows in the opposite direction. It first flows through the motor unit 2 for cooling and lubrication, and then flows back into the main process or returns to the pump chamber 121. Reverse circulation is mainly used to solve the heat dissipation problem of the motor unit 2, which is the key to its ability to safely transport easily vaporized media.

[0049] Furthermore, a coolant jacket 25 is fixedly installed on the outer wall of the motor body 21. The coolant jacket 25 allows coolant to circulate, thereby providing auxiliary cooling for the motor device 2.

[0050] When the gas content of the conveyed medium suddenly increases, although the positive displacement pump is not prone to cavitation, its efficiency will decrease and the medium flow rate will decrease, which may lead to insufficient cooling and lubricating fluid flowing through the motor unit 2, and the motor unit 2 may overheat. The coolant jacket 25 in this solution can cope with this extreme working condition and provide dual cooling protection.

[0051] The pump unit 1 is also equipped with a safety valve assembly, which can automatically release pressure, thereby playing a role in overload protection and avoiding damage.

[0052] The implementation principle of a reverse circulation positive displacement shielded electric pump according to an embodiment of this application is as follows: When the stator winding is energized, a rotating magnetic field is generated. Under the electromagnetic induction effect, the motor rotor 23 can rotate. Then, the motor rotor 23 drives the pump rotor 13 to rotate through the connecting shaft. Multiple sealing cavities with periodically changing volumes can be formed between the inner curved surface of the pump stator 12, the outer surface of the pump rotor 13, the sliding vane 14 sliding in the sliding groove 131 by centrifugal force, and the baffles 15 on both sides of the pump rotor 13. As the pump rotor 13 rotates, the volume of the sealing cavity near the low-pressure area gradually increases, and a negative pressure is generated to draw liquid from the low-pressure area. When the pump rotor 13 rotates a certain angle, the volume of the sealing cavity gradually decreases, thereby squeezing the liquid out of the high-pressure area. Each rotation of the pump rotor 13 completes one process from suction to discharge. Because a positive displacement pump is used, its anti-cavitation ability is much stronger than that of a centrifugal pump, thus facilitating the smooth progress of the transportation process.

[0053] The pumped medium partially flows into the internal circulation of the motor unit 2, carrying away heat. Combined with the external coolant jacket 25, this ensures the long-term stable and reliable operation of the motor unit 2 and the pump unit 1.

[0054] Example 2

[0055] Reference Figure 4 and Figure 5The difference between this embodiment and Embodiment 1 is that in this embodiment, the sliding plate 14 adopts a split structure, including a support block 141, a sliding block 142, and a spring 143. One end of the sliding block 142 is arc-shaped and abuts against the inner wall of the pump stator 12. The arc shape can reduce contact stress. The end of the sliding block 142 away from the pump stator 12 has a receiving groove 1421 along the depth direction of the corresponding slide groove 131. One end of the support block 141 contacts the bottom wall of the slide groove 131, and the other end of the support block 141 extends into the receiving groove 1421 and slides against the inner wall of the receiving groove 1421. The spring 143 is connected between the support block 141 and the sliding block 142. The spring 143 is in a compressed state, so the preload of the spring 143 can make the sliding block 142 always have a tendency to extend outward, and make the end of the sliding block 142 tightly adhere to the inner wall of the pump stator 12, forming an effective seal.

[0056] Furthermore, a guide rod 3 is fixed on the inner wall of the sliding block 142. The guide rod 3 is located in the receiving groove 1421 and is arranged along the depth direction of the receiving groove 1421. A guide hole 1411 is opened at the end of the support block 141 away from the bottom wall of the sliding groove 131. The guide hole 1411 is arranged along the depth direction of the receiving groove 1421. One end of the guide rod 3 is inserted into the guide hole 1411, and the guide rod 3 and the guide hole 1411 can slide relative to each other. A spring 143 is installed in the guide hole 1411. One end of the spring 143 is fixedly connected to the end of the guide rod 3, and the other end of the spring 143 is fixedly connected to the bottom wall of the guide hole 1411. Therefore, the sliding cooperation between the guide rod 3 and the guide hole 1411 can improve the stability of the sliding block 142 during the sliding process. Moreover, the spring 143 is located in the guide hole 1411, which can prevent the spring 143 from directly contacting the conveyed liquid, thereby reducing the corrosion of the spring 143 and helping to ensure the normal use of the spring 143. In addition, spring 143 is made of stainless steel, which further enhances its durability.

[0057] The support block 141 is located in the slide groove 131 and is pressed against the bottom wall of the slide groove 131 by the elastic force of the spring 143. As the speed of the pump rotor 13 increases, the support block 141 will slide radially outward under the action of centrifugal force, that is, the support block 141 will slide towards the side closer to the receiving groove 1421. Since the end of the sliding block 142 is always pressed against the inner wall of the pump stator 12, the spring 143 is further compressed as the support block 141 slides, which further increases the preload force applied by the spring 143 to the sliding block 142, thereby enhancing the sealing performance. As the rotational speed of the pump rotor 13 increases further, the support block 141 continues to slide until the end of the support block 141 contacts the bottom of the receiving groove 1421. At this time, the support block 141 and the sliding block 142 merge into a whole. Due to the increased weight of this whole, the centrifugal force increases, thereby increasing the sealing effect between the sliding vane 14 and the inner wall of the pump stator 12, further ensuring the sealing performance, reducing the leakage of liquid (i.e., internal leakage) between the end of the sliding vane 14 and the pump stator 12, thereby ensuring the working efficiency of the pump device 1.

[0058] The split structure of the vane 14 allows it to adaptively adjust according to the speed changes of the pump rotor 13, maintaining a good seal between the vane 14 and the inner wall of the pump stator 12 while reducing wear between the two.

[0059] Furthermore, a flexible pad (not shown in the figure) is bonded to the bottom wall of the receiving tank 1421 and the end of the support block 141 near the receiving tank 1421. The flexible pad is a rubber pad, which can buffer the impact between the end face of the support block 141 and the bottom wall of the receiving tank 1421, thereby ensuring the stable operation of the pump device 1.

[0060] Example 3

[0061] Reference Figure 6 The difference between this embodiment and Embodiment 2 is that, in this embodiment, to further optimize pressure balance, a through-hole 1422 is provided on the sliding block 142, which connects the receiving groove 1421 to the pump chamber 121. The diameter of the oil drain hole 1422 is small to ensure that sufficient sealing pressure can be established between the sliding block 142 and the inner wall of the pump stator 12, while allowing the medium to slowly seep in to balance the pressure, thereby ensuring the smooth sliding process of the sliding block 142.

[0062] The support block 141 has a balance hole 1412, which connects the receiving groove 1421 and the sliding groove 131. The diameter of the balance hole 1412 can be slightly larger than that of the oil drain hole 1422 to ensure that the support block 141 responds sensitively and can slide smoothly.

[0063] The above are optional embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A reverse-cycle positive-displacement canned motor electric pump, characterized in that, The utility model relates to a pump device (1) and motor device (2) are provided, and the pump device (1) is the vane pump, the pump device (1) includes pump body (11), pump stator (12), pump rotor (13) and vane (14), the pump stator (12) is arranged in the pump body (11), the pump stator (12) is opened in and is equipped with pump cavity (121), the pump rotor (13) eccentric rotation is arranged in the pump cavity (121), a plurality of slide grooves (131) are arranged at the side wall of pump rotor (13) interval, one end of vane (14) is slidably connected with pump rotor (13) and is arranged in the slide groove (131), and the other end of vane (14) is used for being in abutment with the inner wall of pump stator (12). The motor device (2) includes a motor body (21), a motor stator (22) and a motor rotor (23) arranged in the motor body (21). The motor stator (22) is fixedly arranged in the motor body (21). The motor rotor (23) is coaxially fixedly connected with the pump rotor (13) so that the motor rotor (23) rotates under electromagnetic induction and drives the pump rotor (13) to rotate when the motor stator (22) is electrified. A rotor cavity (221) for accommodating the motor rotor (23) is coaxially arranged in the motor stator (22). The rotor cavity (221) is in communication with the pump cavity (121). A liquid discharge port (222) in communication with the rotor cavity (221) is arranged at one end of the motor stator (22) away from the pump device (1). A shielding sleeve (24) is further arranged in the motor body (21). The motor stator (22) is located between the motor body (21) and the shielding sleeve (24).

2. A reverse-circulation positive-displacement canned motor pump according to claim 1, characterized in that: A cooling liquid jacket (25) for circulating cooling liquid is arranged on the outer wall of the motor body (21).

3. A reverse-circulation positive-displacement canned motor pump according to claim 1, characterized in that: The vane (14) includes a support block (141), a sliding block (142) and a spring (143). One end of the sliding block (142) is used for abutting against the inner wall of the pump stator (12). An accommodating groove (1421) for accommodating the support block (141) is arranged at the other end of the sliding block (142). One end of the support block (141) abuts against the bottom wall of the slide groove (131). The other end of the support block (141) is slidably arranged in the accommodating groove (1421). The spring (143) is connected between the support block (141) and the sliding block (142). The spring (143) causes the sliding block (142) to have a tendency to slide away from the support block (141) and causes the end of the sliding block (142) to abut against the inner wall of the pump stator (12).

4. A reverse-circulation positive-displacement canned motor pump according to claim 1, characterized in that: The end of the sliding block (142) away from the support block (141) is arc-shaped.

5. A reverse-circulation positive-displacement canned motor pump according to claim 4, characterized in that: ​ 6. A reverse-circulation positive-displacement canned motor electric pump according to claim 4, characterized in that: The inner wall of the sliding block (142) is fixedly provided with a guide rod (3), the guide rod (3) is located in the accommodating groove (1421), the support block (141) is provided with a guide hole (1411), one end of the guide rod (3) is slidably arranged in the guide hole (1411), the spring (143) is located in the guide hole (1411), and the spring (143) is connected between the end of the guide rod (3) and the bottom wall of the guide hole (1411).

7. A reverse-circulation positive-displacement canned motor pump according to claim 4, characterized in that: The support block (141) is slidably arranged in the sliding groove (131), so that when the sliding block (142) abuts against the inner wall of the pump stator (12), the support block (141) can slide into the accommodating groove (1421) under the action of centrifugal force.

8. A reverse-circulation positive-displacement canned motor pump according to claim 4, characterized in that: The bottom wall of the accommodating groove (1421) and one end of the support block (141) located in the accommodating groove (1421) are provided with flexible pads, and the flexible pad on the bottom wall of the accommodating groove (1421) and the flexible pad on the end of the support block (141) are used to abut against each other.

9. A reverse-circulation positive-displacement canned motor pump according to claim 8, characterized in that: The sliding block (142) is provided with an oil drain hole (1422), one end of the oil drain hole (1422) communicates with the accommodating groove (1421), and the other end of the oil drain hole (1422) communicates with the pump cavity (121).

10. A reverse-circulation positive-displacement canned motor pump according to claim 9, characterized in that: The support block (141) is provided with a balance hole (1412), one end of the balance hole (1412) communicates with the accommodating groove (1421), and the other end of the balance hole (1412) communicates with the sliding groove (131).

Images