Leakage-free canned pump

Abstract

The application provides a leakage-free canned motor pump, belonging to the technical field of pumps. The application solves the problem of large cooling circulation flow resistance of the existing canned motor pump. The leakage-free canned motor pump comprises a pump shell, a motor shell and a rotating shaft, the motor shell is internally fixed with a stator assembly, the stator assembly is internally provided with a rotor assembly fixed with the rotating shaft, the pump shell is provided with a water inlet, a water outlet and a pump cavity, a water passing flow channel is arranged between the inner circumferential wall of the motor shell and the outer circumferential wall of the stator assembly, the inlet of the water passing flow channel is connected with the pump cavity, a water passing hole is arranged in the center of the rotating shaft, the outlet of the water passing flow channel is connected with the water passing hole; the end of the rotor assembly is provided with blades, and the adjacent blades form a flow guiding channel; the bottom wall of the motor shell is provided with a fixed circular ring part, the side wall of the motor shell is provided with a water passing groove, the first water passing gap is left between the end surface of the rotating shaft and the bottom wall, the second water passing gap is left between the lower end surface of the stator assembly and the bottom wall, and the water passing flow channel is connected with the water passing hole through the second water passing gap, the flow guiding channel, the water passing groove and the first water passing gap. The application has the advantages of small flow resistance and high pumping efficiency.

Description

Technical Field

[0001] This invention relates to the field of pump technology, specifically to a leak-free shielded pump. Background Technology

[0002] A canned motor pump is a seal-free pump with an integrated, fully enclosed structure where the motor and pump body are integrated. The stator and rotor are separated by a shielding sleeve, and the pumped medium is cooled by its own circulation. This fundamentally eliminates the risk of leakage caused by the rotating shaft seal, making it particularly suitable for conveying flammable, explosive, toxic, corrosive, or valuable liquids.

[0003] In conventional canned motor pumps, a small portion of the cooling medium is typically drawn from the pump outlet, passes through a filter, and enters the motor cavity. It then flows sequentially through the rear bearing and the gap between the stator and rotor, forming an internal cooling loop. For example, patent CN113404701A discloses a canned motor pump where the cooling channel is such that liquid flows from the pump body through a first connecting hole on the connecting housing into the space between the stator assembly and the hollow shaft. It then flows sequentially through the gap between the stator assembly and the outer rotor assembly, the outside of the outer rotor assembly, and then through a second connecting hole on the end cover into the hollow shaft, finally flowing back to the pump body through the hollow shaft. This channel allows multiple internal motor components to be directly immersed in the medium, enhancing heat dissipation. However, this channel path is tortuous and long, requiring the liquid to pass through multiple narrow, multi-directional gaps, resulting in a significant increase in flow resistance. This high-resistance, tortuous channel can lead to insufficient actual circulation flow, especially under high-flow conditions with small pressure differentials, making it difficult to meet heat dissipation requirements. The complex channel structure increases the pump's manufacturing difficulty and cost, and is also detrimental to later maintenance. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a leak-free canned motor pump. The technical problem this invention seeks to solve is how to provide a cooling channel with low flow resistance and high heat dissipation efficiency while ensuring a compact pump structure and reliable sealing.

[0005] The objective of this invention can be achieved through the following technical solution: a leak-free shielded pump, comprising a pump casing, a motor casing, and a rotating shaft. A stator assembly is fixedly connected inside the motor casing, and a rotor assembly is disposed inside the stator assembly. The rotor assembly is fixedly connected to the rotating shaft. The pump casing has an inlet and an outlet, as well as a pump chamber connecting the inlet and the outlet. A water passage is provided between the motor casing and the stator assembly. The inlet end of the water passage connects to the pump chamber. The rotating shaft has an axially penetrating water passage hole in the middle, and the outlet end of the water passage connects to the water passage hole.

[0006] This design creates a compact, short, and low-resistance cooling circuit by incorporating a water flow channel between the motor housing and the stator assembly, and utilizing the axial water passage in the center of the rotating shaft as a return channel for the cooling medium. This design avoids the complex and tortuous gap channels found in traditional canned motor pumps, effectively reducing the flow resistance of the circulating fluid and ensuring sufficient cooling flow even under high flow conditions, significantly improving motor heat dissipation efficiency. Simultaneously, it simplifies the internal structure of the pump body, reduces manufacturing difficulty and maintenance costs, and improves the operational reliability and service life of the canned motor pump under different operating conditions while maintaining leak-free sealing performance.

[0007] Furthermore, the inner wall of the motor housing has at least two protruding motor ribs that are evenly distributed circumferentially. The inner circumferential surface of each motor rib abuts against and is fixed to the outer circumferential surface of the stator assembly. Two adjacent motor ribs and the stator assembly together form a water flow channel. The motor housing and the motor ribs are integrally formed, wherein the motor ribs are elongated and evenly distributed circumferentially on the inner wall of the motor housing. The shape of the motor ribs can also be arc-shaped or spiral-shaped. The stator assembly includes stator magnets and a stator shielding sleeve that encapsulates and fixes the stator magnets. Here, the stator shielding sleeve includes an inner stainless steel sleeve and a stator molding compound. First, the stator magnets and the inner stainless steel sleeve are pressed and fixed, and then the stator molding compound is molded to make the stator assembly a sealed integral part. Then, the inner stainless steel sleeve of the stator assembly is pressed and fixed to the inner circumferential surface of the motor ribs.

[0008] Furthermore, at least two stator protrusions are fixedly provided on the outer periphery of the stator assembly. These stator protrusions are evenly distributed circumferentially, and their outer circumferential surfaces abut and are fixed to the inner circumferential surface of the motor housing. Two adjacent stator protrusions and the motor housing together form a water passage. The stator assembly includes stator magnets and a stator shielding sleeve that encloses and fixes the stator magnets. The stator protrusions are fixed to the outer periphery of the stator shielding sleeve. The stator protrusions and the stator shielding sleeve are integrally formed by injection molding or by casting and welding.

[0009] Furthermore, the rotor assembly includes a rotor magnet and a rotor support that encloses the rotor magnet. The rotor support is fixedly connected to the rotating shaft. The rotor support has at least two blades protruding outward in the axial direction. A flow channel is formed between two adjacent blades. The flow channel is connected to a water channel and a water passage hole.

[0010] This design incorporates at least two blades on the rotor support, forming a flow channel between adjacent blades. This allows the rotor to actively pump the coolant during rotation, forcing it into the water passages of the rotating shaft, significantly enhancing the driving force and flow of the cooling cycle. Utilizing the rotor's own rotational kinetic energy, this design effectively overcomes flow resistance without requiring additional power components, ensuring sufficient cooling flow even under high flow rates and high pressure differentials. This further improves heat dissipation efficiency and motor operational stability, while also offering a simple, compact structure that is easy to manufacture and assemble.

[0011] Furthermore, a fixed ring portion is formed on the bottom wall of the motor housing, and the rotating shaft is embedded in the fixed ring portion. The rotating shaft and the fixed ring portion are rotatably connected by a rotating assembly.

[0012] Furthermore, a fixed retaining ring is formed at the bottom of the fixed ring portion, one end of the rotating component abuts against the upper end of the fixed retaining ring portion, a first water passage gap is formed between the rotating shaft and the bottom wall of the motor housing, and a water passage groove is also formed on the side wall of the fixed ring portion. The water passage groove extends from the upper end of the fixed retaining ring portion to the bottom wall of the motor housing, and the water passage groove is connected to a water passage hole and a drainage channel.

[0013] Furthermore, the upper end of the fixed ring is embedded in the rotor support, the blades are evenly distributed around the outer periphery of the fixed ring, and a guide plate is fixedly installed in the middle of the outer periphery of the fixed ring, the guide plate being located directly below the blades.

[0014] Furthermore, a second water passage is provided between the stator assembly and the bottom wall of the motor housing, the water passage extending to the bottom wall of the motor housing, and the second water passage connecting the water passage and the drainage channel.

[0015] This design establishes a continuous, low-resistance coolant circulation path by incorporating a fixed annular section and a fixed retaining ring on the bottom wall of the motor housing. This, along with a first water passage gap between the rotating shaft and the bottom wall, a water passage groove on the side wall of the fixed annular section, and a second water passage gap between the stator assembly and the bottom wall, connects the water passage channel, the second water passage gap, the drainage channel, the water passage groove, the first water passage gap, and the water passage hole. Simultaneously, blades are circumferentially distributed around the outer periphery of the fixed annular section, with a guide plate positioned directly below the blades. This guide plate directs the coolant into the drainage channel in an orderly manner, and the pumping force generated by the rotor rotation enhances the circulation drive force. The abutment structure between the rotating assembly and the fixed retaining ring ensures rotational stability. This design achieves active and efficient coolant flow within a compact structure, further reducing flow channel resistance, improving bearing lubrication and cooling, enhancing the heat dissipation performance and operational reliability of the canned motor pump under high flow rate and high pressure differential conditions, and facilitating machining and assembly.

[0016] Furthermore, a front cover is sealed and fixedly connected between the pump housing and the motor housing. The front cover is connected to the rotating shaft via a rotating assembly. At least two axially penetrating water inlet holes are formed on the front cover, connecting the water flow channel and the pump chamber. The front cover supports the rotating shaft, providing end-to-end support, significantly improving the shaft's operational stability and vibration resistance, and extending the lifespan of the bearings and the entire machine. The front cover and pump housing together form the pump chamber. A large third gap exists between the front cover, the stator assembly, and the rotor assembly. The front cover is located between the pump chamber and this third gap, connecting them via the water inlet holes. This means that before entering the water flow channel, the liquid is stored in the third gap. This large spatial gap acts as a buffer and pressure stabilizer, effectively smoothing pressure fluctuations within the pump chamber and reducing the impact and pulsation of the coolant on subsequent flow channels. This ensures a smooth and continuous cooling cycle, further improving heat dissipation and the operational reliability of the canned pump.

[0017] Furthermore, at least two blades protrude outwards from both ends of the rotor support. Liquid enters from the pump chamber through the water flow channel and through the gap between the rotor assembly and the stator assembly.

[0018] Compared with existing technologies, the technical advantages of this invention are as follows: 1. By setting up a flow channel composed of a water passage, water holes in the rotating shaft, and blades on the rotor support, a cooling circuit with a short flow path, few turns, and low resistance is formed. The rotor's rotational kinetic energy is used to actively pump the coolant, significantly enhancing the circulation driving force and ensuring sufficient cooling flow even under harsh conditions such as high flow rate and high pressure differential, effectively improving the motor's heat dissipation efficiency. 2. The rotating shaft adopts a two-end support structure, improving the shaft's operational stability and vibration resistance. Simultaneously, a third gap with a large space is formed between the front cover and the stator and rotor, connecting the pump chamber and the water passage through the water inlet hole, playing a buffering and pressure stabilizing role, smoothing pressure fluctuations, ensuring continuous and stable cooling circulation, and extending the life of the bearings and the entire machine. 3. Compared with the tortuous and narrow traditional flow channels, this invention simplifies the internal structure, reducing manufacturing difficulty and maintenance costs. Attached Figure Description

[0019] Figure 1 This is a cross-sectional view of Embodiment 1 of the present invention.

[0020] Figure 2 This is a perspective view of the motor housing according to Embodiment 1 of the present invention.

[0021] Figure 3 This is a perspective view of the rotor assembly according to Embodiment 1 of the present invention.

[0022] Figure 4 This is a front view of a portion of an embodiment of the present invention.

[0023] Figure 5 This is a perspective view of the front cover of Embodiment 1 of the present invention.

[0024] Figure 6 This is a perspective view of the stator assembly in Embodiment 2 of the present invention.

[0025] Drawing number markings: 1. Pump casing; 11. Inlet; 12. Outlet; 13. Pump chamber; 2. Motor casing; 21. Motor protrusion; 22. Bottom wall; 23. Fixing ring; 24. Fixing retaining ring; 25. Water passage groove; 26. Guide plate; 3. Rotating shaft; 31. Water passage hole; 4. Stator assembly; 41. Stator protrusion; 5. Rotor assembly; 51. Rotor support; 52. Blade; 53. Drainage channel; 6. Water passage channel; 7. Rotating assembly; 81. First water passage gap; 82. Second water passage gap; 83. Third gap; 9. Front cover; 91. Inlet through hole. Detailed Implementation

[0026] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0027] It should be noted that the descriptions of directions such as "upper", "lower", "left", "right", "top", and "bottom" in this invention are defined based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and are not intended to indicate or imply that the device must be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Example

[0028] like Figures 1 to 5 As shown, a leak-free shielded pump includes a pump housing 1, a motor housing 2, and a rotating shaft 3. A stator assembly 4 is fixedly installed inside the motor housing 2, and a rotor assembly 5 is disposed inside the stator assembly 4. The rotor assembly 5 is fixedly connected to the rotating shaft 3 and can drive the rotating shaft 3 to rotate together. The motor housing 2 and the stator assembly 4 are fixedly secured by clamping.

[0029] The pump casing 1 is provided with an inlet 11 and an outlet 12, and the pump casing 1 has a pump chamber 13 that connects the inlet 11 and the outlet 12. A water passage 6 is provided between the inner peripheral wall of the motor housing 2 and the outer peripheral wall of the stator assembly 4. The inlet end of the water passage 6 is connected to the pump chamber 13. At the same time, a fully penetrating water passage 31 is provided axially at the center of the rotating shaft 3. The outlet end of the water passage 6 is connected to the water passage 31.

[0030] To achieve the aforementioned water flow channel 6, multiple motor protrusions 21 are evenly distributed on the inner wall of the motor housing 2. The inner circumferential surface of each motor protrusion 21 is tightly abutted and fixed to the outer circumferential surface of the stator assembly 4, thereby separating the annular space between the motor housing 2 and the stator assembly 4. Thus, two adjacent motor protrusions 21 and the outer wall of the stator assembly 4 together form an axially extending water flow channel 6. This structure ensures reliable fixation while minimizing the flow resistance of the cooling medium.

[0031] Furthermore, the rotor assembly 5 includes a rotor magnet and a rotor support 51 that surrounds and fixes the rotor magnet. The rotor support 51 completely surrounds and fixes the rotor magnet. The rotor support 51 is fixedly connected to the rotating shaft 3 by a key. On the axial end face of the rotor support 51 away from the pump casing 1, multiple blades 52 are formed protruding outward. These blades 52 are evenly distributed circumferentially, and a flow channel 53 is formed between adjacent blades 52. The rotor assembly 5 includes two rotor supports 51, which are located at both ends and sealed and fixed to the rotor inner bushing, the rotor magnet, and the rotor steel sleeve. A sealing element is provided between the rotor inner bushing and the two rotor supports 51. The rotor outer bushing is welded and fixed to the outermost circumferential surface of the two rotor supports 51, forming a rotor assembly 5 that is easy to process and has good sealing performance.

[0032] A fixed annular portion 23 is integrally formed on the bottom wall 22 of the motor housing 2. One end of the rotating shaft 3 is embedded in the fixed annular portion 23 and is rotatably connected to the fixed annular portion 23 through a rotating assembly 7. A fixed retaining ring portion 24 is formed at the bottom of the fixed annular portion 23, and one end of the rotating assembly 7 abuts against the upper end face of the fixed retaining ring portion 24 to achieve axial positioning. A first water passage gap 81 is left between the end face of the rotating shaft 3 and the inner surface of the bottom wall 22 of the motor housing 2. At the same time, multiple water passage grooves 25 are formed on the side wall of the fixed annular portion 23. These water passage grooves 25 extend from the upper end face of the fixed retaining ring portion 24 to the bottom wall 22 of the motor housing 2, connecting the first water passage gap 81 with the space above the fixed annular portion 23.

[0033] A second water passage gap 82 is also provided between the lower end face of the stator assembly 4 and the bottom wall 22 of the motor housing 2. The water passage 6 extends downward to the bottom wall 22 of the motor housing 2 and communicates with the drainage channel 53 on the rotor support 51 through the second water passage gap 82.

[0034] The high-pressure liquid in the pump chamber 13 enters the water passage 6 and flows along the water passage 6 between the motor housing 2 and the stator assembly 4. After reaching the bottom wall 22 of the motor housing 2, it enters the guide channel 53 on the rotor support 51 through the second water passage gap 82. When the rotor assembly 5 rotates, the blades 52 generate a pumping action, forcibly guiding the liquid in the guide channel 53 to the water passage groove 25 on the fixed annular part 23. The liquid passes through the water passage 25 and enters the first water passage gap 81 at the bottom of the rotating shaft 3, and finally enters the water passage hole 31 in the center from the end of the rotating shaft 3. The coolant flows upward along the water passage hole 31 and finally flows back to the low-pressure area of ​​the pump chamber 13, completing a complete cooling cycle.

[0035] A ring-shaped guide plate 26 is fixedly installed at the center of the outer periphery of the fixed annular portion 23. The guide plate 26 is located directly below the blades 52 on the rotor support 51. The guide plate 26 can guide the coolant flowing out from the second water gap 82 to enter the flow channel 53 between the blades 52 more smoothly and orderly, reducing eddies and energy loss, and further improving pumping efficiency.

[0036] A front cover 9 is sealed and fixedly connected between the pump housing 1 and the motor housing 2. This front cover 9 is also connected to the rotating shaft 3 via a rotating assembly 7, thereby supporting the rotating shaft 3 as a two-end support structure, significantly improving the stability of the rotating shaft 3 during operation. The rotating assembly 7 can be a rolling bearing or a sliding bearing.

[0037] The front cover 9 and the pump housing 1 together form the pump chamber 13. Multiple axially penetrating water inlet holes 91 are provided on the front cover 9. These water inlet holes 91 connect the pump chamber 13 to the inlet end of the water flow channel 6. A relatively large third gap 83 is formed between the front cover 9, the stator assembly 4, and the rotor assembly 5. The coolant in the pump chamber 13 first enters this relatively large third gap 83, which acts as a buffer and stabilizes the pressure, and then enters the water flow channel 6 through the water inlet holes 91. This design effectively suppresses pressure fluctuations within the pump chamber 13, ensuring a more stable cooling cycle.

[0038] The rotor support 51 has been further improved. Multiple blades 52 protrude outwards from both axial ends of the rotor support 51, namely the end near the pump housing 1 and the end near the bottom wall 22 of the motor housing 2. Correspondingly, gaps for coolant passage are formed between the bottom wall 22 of the motor housing 2 and the stator assembly 4, and between the front cover 9 and the stator assembly 4. This design also allows coolant to enter the motor from the pump chamber 13 through the radial gap between the rotor assembly 5 and the stator assembly 4, further increasing the cooling circulation path and efficiency. Example

[0039] according to Figure 6As shown, in this embodiment, instead of providing protrusions on the inner wall of the motor housing 2, multiple stator protrusions 41 are fixedly provided on the outer circumferential surface of the stator assembly 4. These stator protrusions 41 are evenly distributed circumferentially, and the outer circumferential surface of each stator protrusion 41 abuts tightly against the inner circumferential surface of the motor housing 2. Two adjacent stator protrusions 41 and the inner wall of the motor housing 2 together form a water passage. The stator protrusions 41 can be integrally formed with the stator shielding sleeve of the stator assembly 4 by injection molding, casting, or welding, simplifying the manufacturing process.

[0040] The above embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection defined by the claims of the present invention.

Claims

1. A leak-free shielded pump, comprising a pump casing (1), a motor casing (2), and a rotating shaft (3), wherein a stator assembly (4) is fixedly connected inside the motor casing (2), and a rotor assembly (5) is disposed inside the stator assembly (4), the rotor assembly (5) being fixedly connected to the rotating shaft (3), and the pump casing (1) having an inlet (11) and an outlet (12) and a pump chamber (13) connecting the inlet (11) and the outlet (12), characterized in that: A water passage (6) is provided between the motor housing (2) and the stator assembly (4). The inlet end of the water passage (6) is connected to the pump chamber (13). The middle part of the rotating shaft (3) has an axially penetrating water passage hole (31). The outlet end of the water passage (6) is connected to the water passage hole (31).

2. The leak-free shielded pump according to claim 1, characterized in that: The inner wall of the motor housing (2) is provided with at least two motor protrusions (21). The motor protrusions (21) are evenly distributed in the circumferential direction. The inner circumferential surface of the motor protrusions (21) abuts against and is fixed to the outer circumferential surface of the stator assembly (4). Two adjacent motor protrusions (21) and the stator assembly (4) together form a water passage (6).

3. The leak-free shielded pump according to claim 1, characterized in that: At least two stator protrusions (41) are fixedly provided on the outer periphery of the stator assembly (4). The stator protrusions (41) are evenly distributed in the circumferential direction. The outer peripheral surface of the stator protrusions (41) abuts against and is fixed to the inner peripheral surface of the motor housing (2). Two adjacent stator protrusions (41) and the motor housing (2) together form a water passage.

4. A leak-free shielded pump according to any one of claims 1 to 3, characterized in that: The rotor assembly (5) includes a rotor magnet and a rotor support (51) that encloses the rotor magnet. The rotor support (51) is fixedly connected to the rotating shaft (3). The rotor support (51) has at least two blades (52) protruding outward in the axial direction. A drainage channel (53) is formed between two adjacent blades (52). The drainage channel (53) is connected to a water channel and a water passage hole (31).

5. A leak-free shielded pump according to claim 4, characterized in that: A fixed ring portion (23) is formed on the bottom wall (22) of the motor housing (2). The rotating shaft (3) is embedded in the fixed ring portion (23). The rotating shaft (3) and the fixed ring portion (23) are rotatably connected by a rotating assembly (7).

6. A leak-free shielded pump according to claim 5, characterized in that: The bottom of the fixed ring part (23) is formed with a fixed retaining ring part (24). One end of the rotating component (7) abuts against the upper end of the fixed retaining ring part (24). There is a first water passage gap (81) between the rotating shaft (3) and the bottom wall (22) of the motor housing (2). A water passage groove (25) is also formed on the side wall of the fixed ring part (23). The water passage groove (25) extends from the upper end of the fixed retaining ring part (24) to the bottom wall (22) of the motor housing (2). The water passage groove (25) is connected to the water passage hole (31) and the drainage channel (53).

7. A leak-free shielded pump according to claim 6, characterized in that: The upper end of the fixed ring part (23) is embedded in the rotor bracket (51), and the blades (52) are evenly distributed around the outer periphery of the fixed ring part (23). A guide plate (26) is fixedly installed in the middle of the outer periphery of the fixed ring part (23), and the guide plate (26) is located directly below the blades (52).

8. A leak-free shielded pump according to claim 7, characterized in that: There is a second water passage gap (82) between the stator assembly (4) and the bottom wall (22) of the motor housing (2), the water passage channel (6) extends to the bottom wall (22) of the motor housing (2), and the second water passage gap (82) connects the water passage channel (6) and the drainage channel (53).

9. A leak-free shielded pump according to claim 5, characterized in that: A front cover (9) is sealed and fixedly connected between the pump housing (1) and the motor housing (2). The front cover (9) is connected to the rotating shaft (3) through a rotating assembly (7). At least two axially penetrating water inlet holes (91) are formed on the front cover (9). The water inlet holes (91) are connected to the water flow channel (6) and the pump chamber (13).

10. A leak-free shielded pump according to claim 4, characterized in that: The rotor support (51) has at least two blades (52) protruding outward at both ends of its axial direction.

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