A shielded electric pump with impeller thrust automatic balance

Abstract

The utility model relates to a shielded electric pump of impeller thrust automatic balance mainly includes pump cavity mechanism and drive mechanism. Pump cavity mechanism contains pump body, front bearing seat and the impeller in pump cavity, the front bearing seat and pump body form the pump cavity, and the impeller near the front bearing seat side is connected fixed throttling ring, and the front bearing seat near the impeller side is connected flow channel ring. Form fixed throttling gap and variable throttling gap between the two, and the flow channel ring is equipped with a plurality of first through -hole in circumference, and the fixed throttling ring is equipped with a plurality of second through -hole in circumference, and the front bearing seat near the second through -hole is equipped with pressure balance cavity. Drive mechanism contains the pump shaft of one end connected impeller, and the pump shaft is successively covered front bearing sealing assembly, rotor assembly, rear bearing sealing assembly and rear bearing seat, and the outside of rotor assembly is successively equipped with stator subassembly and pump shell. The electric pump passes through the two annular gaps of fixed throttling ring and flow channel ring, controls pump cavity pressure to adjust the impeller movement and the width of variable throttling gap, balances the axial thrust of impeller, prolongs the service life.

Description

Technical Field

[0001] This utility model relates to the field of shielded electric pump technology, specifically to a shielded electric pump with automatic impeller thrust balancing. Background Technology

[0002] As a leak-free conveying device, the impeller of a canned motor pump generates axial force due to uneven pressure distribution of the medium during high-speed rotation. If this axial force cannot be effectively balanced, it can lead to increased friction and wear between the impeller and pump body components, shaft bending and deformation, shortened bearing life, and in severe cases, equipment vibration, abnormal noise, or even shutdown. Existing axial force balancing schemes for canned motor pumps have the following technical defects and drawbacks: 1. Traditional balance hole / balance disc solution: Balance holes need to be opened in the impeller cover plate or an additional balance disc needs to be configured. This not only damages the impeller hydraulic structure and reduces hydraulic efficiency (efficiency loss is usually 5-8%), but also makes the balance holes easy to be blocked by media impurities, leading to balance failure. The balance disc relies on precision fit, and the sealing surface is prone to corrosion and wear in highly corrosive media, resulting in poor balance reliability.

[0003] 2. Symmetrical arrangement of dual impellers: This requires a reverse installation structure of dual impellers, which increases the pump body size and manufacturing cost. It is only suitable for specific flow conditions. When operating under varying conditions, the balance accuracy drops significantly and it cannot meet the needs of complex operating conditions.

[0004] 3. Separate design of guide vane and impeller: In existing shielded pumps with guide vanes, the guide vanes only play a role in guiding and stabilizing the flow, and do not participate in axial force balancing. Axial force balancing still needs to rely on other auxiliary structures, resulting in a complex overall structure, high assembly difficulty, poor coordination among multiple structures, and delayed balancing response.

[0005] Furthermore, existing solutions generally lack automatic adjustment capabilities. When parameters such as viscosity, pressure, and flow rate of the conveyed medium fluctuate, the axial force balance cannot be adapted in real time, easily leading to dynamic imbalance problems. Therefore, developing an impeller balancing mechanism that integrates fins, back rings, balance discs, variable balance holes, and especially a uniquely designed flow channel ring, with automatic axial force balancing capabilities, a compact structure, and high reliability, has become a key direction for the technological upgrade of canned motor pumps. Utility Model Content

[0006] The purpose of this invention is to overcome at least one of the defects of the prior art and provide a shielded electric pump with automatic impeller thrust balancing.

[0007] The objective of this utility model can be achieved through the following technical solutions: A shielded electric pump with automatic impeller thrust balancing, comprising: A pump chamber mechanism includes a pump body, a front bearing housing that surrounds the pump body to form a pump chamber, and an impeller disposed within the pump chamber. A fixed throttling ring is fixedly connected to the side of the impeller near the front bearing housing, and a flow channel ring is fixedly connected to the side of the front bearing housing near the impeller. The gap between the fixed throttling ring and the front bearing housing constitutes a fixed throttling ring gap, and the gap between the fixed throttling ring and the flow channel ring constitutes a variable throttling ring gap. The flow channel ring is provided with a plurality of first through holes spaced apart along its circumference, and the fixed throttling ring is provided with a plurality of second through holes spaced apart along its circumference. A pressure balance chamber is provided in the portion of the front bearing housing near the second through holes. The drive mechanism includes a pump shaft with one end connected to the impeller drive, and a front bearing sealing assembly, a rotor assembly, a rear bearing sealing assembly and a rear bearing housing sequentially sleeved on the pump shaft. A stator assembly and a pump casing are sequentially arranged on the outside of the rotor assembly. Furthermore, fins are provided circumferentially at intervals on one side of the impeller near the fixed throttling ring.

[0008] Furthermore, the impeller and the fixed throttling ring are welded together or bolted together.

[0009] Furthermore, the front bearing housing is welded to or bolted to the flow channel ring.

[0010] Furthermore, an impeller nut is provided between the pump shaft and the impeller for connecting the two.

[0011] Furthermore, the front bearing housing is sleeved on the pump shaft, and the front bearing sealing assembly is disposed within the front bearing housing.

[0012] Furthermore, a stator front flange is provided between the stator assembly and the front bearing housing to connect the two.

[0013] Furthermore, a stator rear flange is provided between the stator assembly and the rear bearing housing to connect the two.

[0014] Furthermore, a pair of thrust discs are also fitted onto the pump shaft, and the pair of thrust discs are respectively disposed on both sides of the rotor assembly.

[0015] Furthermore, the shielded electric pump is also provided with a support for supporting the stator assembly.

[0016] Furthermore, the support body is a shock-absorbing support seat.

[0017] Compared with the prior art, the present invention has the following advantages: (1) This utility model provides a shielded electric pump with automatic impeller thrust balancing. The shielded electric pump forms a fixed throttling ring gap and a variable throttling ring gap by a fixed throttling port ring fixed on one side of the impeller and a flow channel ring on the front bearing seat. By controlling the pressure in the pump chamber, the movement of the impeller can be controlled, thereby controlling the width of the variable throttling ring gap, so as to balance the axial thrust generated when the impeller is running and effectively extend the service life of the shielded electric pump.

[0018] (2) This utility model provides a canned electric pump with automatic impeller thrust balancing. The canned electric pump forms a complete pressure buffer and drainage channel by fixing a flow channel ring on the front bearing housing, and cooperating with the first through hole of the flow channel ring, the second through hole of the fixed throttling ring, and the pressure balancing cavity of the front bearing housing. This structure can effectively eliminate the vortex disturbance generated when the impeller rear cover plate and fins drive the liquid movement, quickly smooth out pressure pulsation, eliminate operational interference, and significantly improve the operational stability of the canned electric pump under different working conditions.

[0019] (3) This utility model provides a shielded electric pump with automatic impeller thrust balancing. The front bearing housing of the shielded electric pump is provided with a flow channel ring. The flow channel ring can eliminate the pressure disturbance and pulsation caused by the liquid vortex driven by the impeller rear cover plate and fins, eliminate interference and improve stability.

[0020] (4) This utility model provides a shielded electric pump with automatic impeller thrust balancing. The fins arranged circumferentially on the impeller of the shielded electric pump can optimize the medium flow field distribution, reduce pressure fluctuations, and further improve the response speed and stability of thrust balancing. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a canned electric pump with automatic impeller thrust balancing in the embodiment. Figure 2 for Figure 1 A magnified view of a portion of the text; Figure 3 This is a cross-sectional view of the impeller in the embodiment; Figure 4 This is a front view of the impeller in the embodiment; Figure 5 This is a cross-sectional view of the flow channel ring in the embodiment; Figure 6 This is one of the usage status diagrams of the canned electric pump with automatic impeller thrust balancing in the embodiment; Figure 7 This is the second diagram showing the usage status of the shielded electric pump with automatic impeller thrust balancing in the embodiment. The numbers in the diagram indicate: 1-Pump body; 2-Impeller; 3-Fixed throttling ring; 4-Flow channel ring; 5-Front bearing housing; 6-Front bearing sealing assembly; 7-Stator assembly; 8-Rotor assembly; 9-Pump shaft; 10-Pump casing; 11-Rear bearing sealing assembly; 12-Rear bearing housing; 13-Stator front flange; 14-Stator rear flange; 15-Thrust disc; 16-Support body; 201-Fin; 301-Second through hole; 401-First through hole; 401-Counterhead; a-Fixed throttling ring clearance; b-Variable throttling ring clearance; c-Pressure balance chamber. Detailed Implementation

[0022] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are implemented based on the technical solution of the present invention, providing detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0023] Example This embodiment provides a shielded electric pump with automatic impeller thrust balancing; see the specific structure below. Figure 1-5 ,include: The pump chamber mechanism includes a pump body 1, a front bearing housing 5 that surrounds the pump body 1 to form a pump chamber, and an impeller 2 disposed within the pump chamber. A fixed throttling ring 3 is fixedly connected to the side of the impeller 2 near the front bearing housing 5, and a flow channel ring 4 is fixedly connected to the side of the front bearing housing 5 near the impeller 2. The gap between the fixed throttling ring 3 and the front bearing housing 5 constitutes a fixed throttling ring gap a, and the gap between the fixed throttling ring 3 and the flow channel ring 4 constitutes a variable throttling ring gap b. The flow channel ring 4 is provided with a plurality of first through holes 401 spaced apart along its circumference, and the fixed throttling ring 3 is provided with a plurality of second through holes 301 spaced apart along its circumference. A pressure balancing chamber c is provided in the portion of the front bearing housing 5 near the second through holes 301. The drive mechanism includes a pump shaft 9, one end of which is connected to the impeller 2 for transmission, and a front bearing sealing assembly 6, a rotor assembly 8, a rear bearing sealing assembly 11, and a rear bearing housing 12 sequentially sleeved on the pump shaft 9. A stator assembly 7 and a pump housing 10 are sequentially arranged on the outside of the rotor assembly 8. The front bearing sealing assembly 6 and the rear bearing sealing assembly 13 both contain accessories such as bearing housings, bearings, bushings, and mechanical seals. The bushing is made of silicon carbide.

[0024] In this embodiment, fins 201 are arranged circumferentially on one side of the impeller 2 near the fixed throttling ring 3. The fins 201 can guide and rectify the flow of the medium in the pump chamber, optimize the flow field distribution, and reduce local pressure changes. The flow channel ring 4 eliminates the pressure disturbances and pulsations caused by the liquid vortex driven by the rear cover plate and fins 201 of the impeller 2.

[0025] In this embodiment, the impeller 2 and the fixed throttling ring 3 are welded together or bolted together.

[0026] Optionally, the front bearing housing 5 is welded to the flow channel ring 4 or bolted to it. In this embodiment, the two are bolted together and connected by screwing into the countersunk hole 402 of the flow channel ring 4.

[0027] In this embodiment, an impeller nut is provided between the pump shaft 9 and the impeller 2 to connect the two.

[0028] In this embodiment, the front bearing housing 5 is sleeved on the pump shaft 9, and the front bearing sealing assembly 6 is disposed inside the front bearing housing 5.

[0029] In this embodiment, a stator front flange 13 is provided between the stator assembly 7 and the front bearing housing 5 to connect the two.

[0030] In this embodiment, a stator rear flange 14 is provided between the stator assembly 7 and the rear bearing housing 12 to connect the two.

[0031] In this embodiment, a pair of thrust discs 15 are also sleeved on the pump shaft 9, and the pair of thrust discs 15 are respectively disposed on both sides of the rotor assembly 8.

[0032] In this embodiment, the shielded electric pump is further provided with a support body 16 for supporting the stator assembly 7. The support body 16 is a shock-absorbing support seat. An arc-shaped pad is provided on the shock-absorbing support seat, and rubber is placed on the arc-shaped pad for connection and fixation. This can effectively reduce the vibration of the shielded pump during operation, ensure good internal structural sealing, and extend service life.

[0033] Working principle: When impeller 2 moves to the left (see...) Figure 6 (Arrow direction shown): The variable throttling annular gap b is fully open, impeller 2 drives fins 201 to pump the medium, a low-pressure zone is formed on the back of impeller 2, the back pressure of impeller 2 decreases, and the pressure acting on the front cover plate of impeller 2 is greater than the pressure on the rear cover plate of impeller 2. The pressure difference causes impeller 2 to move to the right as a whole, pushing the system to reset backward; when impeller 2 moves to the right (see...) Figure 7 (As indicated by the arrow direction): The variable throttling annular gap b closes, blocking the pressure balance with the low-pressure zone behind impeller 2. Consequently, the pressure in the pressure balance chamber c rises, generating a reverse resultant force that pushes impeller 2 forward to reset. However, in the actual operation of the canned motor pump, the pressure inside the pump chamber is regulated between high and low pressure. The resultant force and displacement are gradually corrected to a certain position, at which point the generated force is zero. The moving parts remain stable and completely balanced between high and low pressure to balance the axial thrust generated during impeller operation, effectively extending the service life of the canned motor pump.

[0034] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from its technical solution shall still fall within the protection scope of this utility model.

Claims

1. A shielded electric pump with automatic impeller thrust balancing, characterized in that, include: The pump chamber mechanism includes a pump body (1), a front bearing housing (5) that surrounds the pump body (1) to form a pump chamber, and an impeller (2) disposed in the pump chamber; a fixed throttling ring (3) is fixedly connected to the side of the impeller (2) near the front bearing housing (5), and a flow channel ring (4) is fixedly connected to the side of the front bearing housing (5) near the impeller (2); the gap between the fixed throttling ring (3) and the front bearing housing (5) constitutes a fixed throttling ring gap (a); the gap between the fixed throttling ring (3) and the flow channel ring (4) constitutes a variable throttling ring gap (b); the flow channel ring (4) is provided with a plurality of first through holes (401) spaced apart along its circumference; the fixed throttling ring (3) is provided with a plurality of second through holes (301) spaced apart along its circumference; and a pressure balancing chamber (c) is provided in the part of the front bearing housing (5) near the second through holes (301). The drive mechanism includes a pump shaft (9) that is connected to the impeller (2) at one end, and a front bearing sealing assembly (6), a rotor assembly (8), a rear bearing sealing assembly (11) and a rear bearing housing (12) sequentially mounted on the pump shaft (9). A stator assembly (7) and a pump casing (10) are sequentially arranged on the outside of the rotor assembly (8).

2. The shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, The impeller (2) has fins (201) spaced around its circumference on the side near the fixed throttling ring (3).

3. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, The impeller (2) and the fixed throttling ring (3) are welded or bolted together; the front bearing seat (5) and the flow channel ring (4) are welded or bolted together.

4. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, An impeller nut is provided between the pump shaft (9) and the impeller (2) for connecting the two.

5. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, The front bearing housing (5) is sleeved on the pump shaft (9), and the front bearing sealing assembly (6) is disposed inside the front bearing housing (5).

6. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, A stator front flange (13) is provided between the stator assembly (7) and the front bearing housing (5) to connect the two.

7. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, A stator rear flange (14) is provided between the stator assembly (7) and the rear bearing housing (12) to connect the two.

8. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, A pair of thrust discs (15) are also fitted on the pump shaft (9), and the pair of thrust discs (15) are respectively arranged on both sides of the rotor assembly (8).

9. A shielded electric pump with automatic impeller thrust balancing according to claim 1, characterized in that, The shielded electric pump is also provided with a support (16) for supporting the stator assembly (7).

10. A shielded electric pump with automatic impeller thrust balancing according to claim 9, characterized in that, The support (16) is a shock-absorbing support seat.

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