Shield pump with axial force balancing unit

Abstract

The utility model relates to the technical field of shield pumps, and provides a shield pump with an axial force balancing unit, which comprises a pump shaft, a pump head unit, a shield motor unit, the axial force balancing unit, a heat exchanger unit and a metering pump unit, the shielding motor unit comprises a stator assembly and a rotor. The stator assembly comprises a motor shell front cover, a motor shell, a stator and a motor shell rear cover; the motor shell front cover and the motor shell rear cover are arranged at the two ends of the motor shell respectively, and the stator is arranged in the motor shell. The rotor is arranged on the pump shaft and located in the stator. The axial force balancing unit comprises a balancing ring, a balancing disc and an outer shell. The balance disc is fixed at the tail end of the pump shaft, and a balance hole is formed in the center of the pump shaft; a balance ring is fixed on the balance disc; and the outer shell is connected with the shielding motor unit. The shield pump can still balance axial force after the impeller is abraded by medium particles, and long-term stable operation of the pump is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of shielded pumps, in particular to a shielded pump with a balanced axial force unit. Background Art

[0002] The canned pump is a combination of a centrifugal pump and a canned motor. The centrifugal pump and the canned motor share a shaft supported by a pair of sliding bearings. The stator and rotor of the canned pump are inlaid with a shielding sleeve, which isolates the medium from the stator and rotor of the motor. The canned pump has only static seals but no dynamic seals. Since the canned pump solves the problems of running, bubbling, dripping, and leaking, it can be safe and leak-free and is widely used in the fields of chemical industry, petrochemical industry, nuclear power, medicine, refrigeration, etc., especially for corrosive, radioactive, toxic and harmful media.

[0003] Due to various reasons such as the different sizes of the front and rear covers of the impeller and the imbalance of pressure, the shielded pump will generate axial force. If the axial force cannot be well balanced, it will have a great impact on the service life, efficiency, and life cycle cost of the shielded pump.

[0004] Due to the small gap between the stator shielding sleeve and the rotor shielding sleeve of the shielded pump and the small gap between the sliding bearings, the medium passing through the gap between the stator shielding sleeve and the rotor shielding sleeve and the sliding bearings must not contain particles. Particles will cause the shielding sleeve to wear, the sliding bearing to wear and break, and the pump to be damaged. However, the media in the chemical and petrochemical industries often contain particles. At present, users in the industry use mud-type shielded pumps, most of which are external flushing methods. The pressure chamber formed by the balance hole of the pump head impeller and the gap between the mouth ring balances the axial force. However, when the gap between the mouth rings becomes larger due to the wear of particles in the medium, the axial force balance is immediately destroyed, and the axial movement of the rotating parts damages the bearings and then the pump. Utility Model Content

[0005] The utility model mainly solves the technical problem that for medium containing particles, a mud-type shielded pump is currently used. When the medium is worn by particles and the mouth ring gap becomes larger, the axial force balance is immediately destroyed, the axial movement of the rotating parts damages the bearing and then the pump. A shielded pump with a balanced axial force unit is proposed. After the impeller is worn by medium particles, the shielded pump can still balance the axial force to ensure the long-term stable operation of the pump.

[0006] The utility model provides a canned pump with a balanced axial force unit, comprising: a pump shaft, a pump head unit, a canned motor unit, a balanced axial force unit, a heat exchanger unit and a metering pump unit;

[0007] The pump shaft passes through the pump head unit, the shielded motor unit and the balanced axial force unit;

[0008] The pump head unit comprises: a pump body and an impeller; the impeller is arranged in the pump body, and the impeller is fixed to the front end of the pump shaft;

[0009] The shielded motor unit comprises: a stator assembly and a rotor; the stator assembly comprises a motor housing front cover, a motor housing, a stator and a motor housing rear cover; the motor housing front cover and the motor housing rear cover are respectively arranged at two ends of the motor housing, and the stator is arranged inside the motor housing; the rotor is arranged on the pump shaft and is located inside the stator;

[0010] The balancing axial force unit comprises: a balancing ring, a balancing disc and an outer shell; the balancing disc is fixed to the end of the pump shaft, and a balancing hole is opened in the center of the pump shaft; a balancing ring is fixed on the balancing disc; the outer shell is connected to the shielded motor unit, and the outer shell is connected to the heat exchanger unit;

[0011] The metering pump unit is connected to the heat exchanger unit.

[0012] Preferably, the pump body is connected to the shielded motor unit via a connecting section;

[0013] The connecting section is connected to the shielded motor unit via a through-bar;

[0014] An auxiliary bearing and an auxiliary impeller are installed inside the connecting section;

[0015] The connecting section is provided with a circulation hole for connecting with the heat exchanger unit.

[0016] Preferably, the pump head unit further comprises: a wear-resistant plate and a mouth ring;

[0017] The wear-resistant plate is fixedly connected to the connecting section; and the mouth ring is inlaid on the pump body.

[0018] Preferably, a stator shielding sleeve is embedded inside the stator assembly, and the stator shielding sleeve is welded to the stator shielding plates at both ends of the motor housing front cover and the motor housing rear cover respectively;

[0019] The outer circumference of the rotor is inlaid with a rotor shielding sleeve, the rotor shielding sleeve is welded to the rotor shielding plates inlaid at both ends of the rotor, and the rotor shielding plates are welded to the pump shaft;

[0020] There is a gap between the stator shielding sleeve and the rotor shielding sleeve.

[0021] Preferably, a front bearing body is installed at the front end of the shielded motor unit, and a rear bearing body is installed at the rear end;

[0022] The front bearing body is provided with a circulation hole, and the rear bearing body is provided with two circulation holes;

[0023] The two circulation holes of the rear bearing body are respectively connected to the medium inlet heat exchanger circulation pipe and the balanced axial force circulation pipe;

[0024] The rear bearing body is fixed on the rear cover of the motor housing by the outer housing.

[0025] Preferably, a balance ring seat is fixed on the rear bearing body, and a balance ring is arranged on the balance ring seat;

[0026] The balancing ring is fixed on the balancing disk; the balancing disk is key-connected to the pump shaft.

[0027] Preferably, a front main bearing, a rear main bearing and a set of auxiliary sliding bearing assemblies are installed inside the shielded motor unit;

[0028] The front main bearing and the rear main bearing are arranged on the pump shaft, the front main bearing is fixedly connected to the front bearing body; the rear main bearing is fixedly connected to the rear bearing body;

[0029] The auxiliary sliding bearing assembly is fixedly connected to the connecting section.

[0030] Preferably, a circulation hole is opened on the pump shaft.

[0031] Preferably, the heat exchanger unit comprises: a heat exchanger body, a medium inlet heat exchanger circulation pipe, a medium outlet heat exchanger circulation pipe and a balanced axial force circulation pipe;

[0032] The heat exchanger body is connected with the medium inlet heat exchanger circulation pipe, the medium outlet heat exchanger circulation pipe and the balanced axial force circulation pipe through the medium inlet heat exchanger circulation pipe.

[0033] Preferably, the metering pump unit comprises: a metering pump and a safety valve;

[0034] The metering pump is connected to the heat exchanger body through a medium inlet heat exchanger circulation pipe.

[0035] The utility model provides a shielded pump with a balanced axial force unit, which is provided with a metering pump unit, a balanced axial force unit, and a heat exchanger unit. The metering pump unit, the external heat exchanger unit, and the shielded motor unit form independent cycles respectively, and the pressure is higher than the pressure of the pump head unit, so as to ensure that the medium with particles does not enter the motor unit and wear the sliding bearing and the stator and rotor shielding sleeve; the balanced axial force unit can ensure that the axial force of the whole pump remains balanced after the gap of the ring of the pump head impeller is worn by the particle medium, and ensure that the pump will not be damaged due to the imbalance of the axial force caused by the wear. The utility model can prevent the medium with solid particles in the pump head unit from entering the motor cavity and damaging the bearing, and can ensure that the rear balanced axial force unit can still balance the axial force of the whole pump after the gap between the impeller and the wear-resistant plate of the pump head unit is enlarged due to the wear of solid particles and the axial force balance is destroyed, so as to ensure that the shielded pump will not be damaged due to the imbalance of the axial force. The utility model can ensure that the shielded pump can balance the axial force when conveying a medium containing a large amount of particles, and the pump can operate stably and reliably for a long time. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of a canned pump with a balanced axial force unit provided by the utility model;

[0037] Figure 2 yes Figure 1 Middle A-direction view;

[0038] Figure 3 yes Figure 1 Circulation diagram of ;

[0039] Figure 4 yes Figure 1 A partial enlarged view of the front end of the middle shield motor unit.

[0040] 1. Pump housing; 2. Impeller; 3. Wear plate; 4. Mouth ring; 5. Auxiliary bearing; 6. Connecting section; 7. Auxiliary impeller; 8. Front bearing body; 9. Front main bearing; 10. Front cover of motor housing; 11. Rotor; 12. Rotor shielding sleeve; 13. Stator shielding sleeve; 14. Rotor shielding plate; 15. Rear main bearing; 16. Rear cover of motor housing; 17. Stator shielding plate; 18. Rear bearing body; 19. Balance ring seat; 20. Balance ring; 21. Balance disk; 22. Outer housing; 23. Stator; 24. Motor housing; 25. Heat exchanger body; 26. Medium out of heat exchanger circulation pipe; 27. Through bar; 28. Medium inlet of heat exchanger circulation pipe; 29. ​​Balance axial force circulation pipe; 30. Safety valve; 31. Metering pump; 32. Metering pump inlet; 33. Pump shaft; 34. Stud. DETAILED DESCRIPTION

[0041] In order to make the technical problems solved by the present invention, the technical solutions adopted and the technical effects achieved clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for the sake of ease of description, only the parts related to the present invention are shown in the accompanying drawings, rather than all of the contents.

[0042] like Figure 1-4 As shown, an embodiment of the utility model provides a canned pump with a balanced axial force unit, including: a pump shaft 33, a pump head unit, a canned motor unit, a balanced axial force unit, a heat exchanger unit and a metering pump unit.

[0043] The pump shaft 33 passes through the pump head unit, the shielded motor unit and the balancing axial force unit. The pump shaft 33 is a hollow shaft in its entirety or in part. A circulation hole (balancing axial force circulation hole C) is opened on the pump shaft 33, and the circulation hole C can be opened before the auxiliary impeller 7 or the impeller 2 according to the size of the axial force balance.

[0044] The pump head unit comprises: a pump body 1 and an impeller 2; the impeller 2 is arranged in the pump body 1, and the impeller 2 is tightened and fixed to the front end of the pump shaft 33 by an impeller nut.

[0045] The pump body 1 is connected to the shielded motor unit through the connecting section 6; the connecting section 6 is connected to the shielded motor unit through the through rod 27, and the through rod 27 tightens the various parts of the stator assembly; the auxiliary bearing 5 and the auxiliary impeller 7 are installed inside the connecting section 6. The auxiliary impeller 7 is key-mounted on the pump shaft 33. The connecting section 6 is provided with a circulation hole connected to the heat exchanger unit, specifically connected to the medium outlet heat exchanger circulation pipe 26 of the heat exchanger unit.

[0046] The pump head unit further comprises: a wear-resistant plate 3 and a mouth ring 4; the wear-resistant plate 3 is fixedly connected to the connecting section 6; the mouth ring 4 is mounted on the pump body and forms a gap with the front mouth ring of the impeller 2.

[0047] The shielded motor unit includes: a stator assembly and a rotor 11; the stator assembly includes a motor housing front cover 10, a motor housing 24, a stator 23 and a motor housing rear cover 16; the motor housing front cover 10 and the motor housing rear cover 16 are respectively arranged at both ends of the motor housing 24, and the stator 23 is arranged inside the motor housing 24; the rotor 11 is arranged on the pump shaft 33 and is located inside the stator 23.

[0048] The stator assembly is embedded with a stator shielding sleeve 13, which is respectively welded to the stator shielding plates 17 at both ends of the motor housing front cover 10 and the motor housing rear cover 16, specifically by argon arc welding, to ensure that the shielded stator assembly is isolated from the conveying medium. The outer circumference of the rotor 11 is embedded with a rotor shielding sleeve 12, which is welded to the rotor shielding plates 14 embedded at both ends of the rotor 11, and the rotor shielding plates 14 are welded to the pump shaft 33, specifically by argon arc welding, to ensure that the rotor 11 is completely isolated from the conveying medium. There is a gap between the stator shielding sleeve 13 and the rotor shielding sleeve 12, but the gap is small.

[0049] The front bearing body 8 is installed at the front end of the shielded motor unit, and the rear bearing body 18 is installed at the rear end; the front bearing body 8 is fixed to the front cover 10 of the motor housing by screws. The front bearing body 8 is provided with circulation holes, which are evenly distributed and one of the circulation holes must be directly above. The number and size of the circulation holes are determined according to the circulation volume of the shielded motor. The rear bearing body 18 is provided with two circulation holes (circulation hole A and circulation hole B, and circulation hole A is directly above the rotor cavity); the two circulation holes of the rear bearing body 18 are respectively connected to the medium inlet heat exchanger circulation pipe 28 and the balanced axial force circulation pipe 29, the circulation hole A is connected to the medium inlet heat exchanger circulation pipe 28, and the circulation hole B is connected to the medium outlet heat exchanger circulation pipe 29. The rear bearing body 18 is fixed to the rear cover 16 of the motor housing by the outer shell 22. A junction box is provided on the shielded motor unit, and the junction box is connected to the lead wire of the coil wound on the stator 23.

[0050] A balancing ring seat 19 is fixed on the rear bearing body 18 , and a balancing ring 20 is arranged on the balancing ring seat 19 ; the balancing ring 20 is fixed on a balancing disc 21 ; the balancing disc 21 is key-connected to the pump shaft 33 , and is fixed to the pump shaft 33 with a shaft nut.

[0051] A front main bearing 9, a rear main bearing 15 and a set of auxiliary sliding bearing assembly 5 are installed inside the shielded motor unit; the front main bearing 9 and the rear main bearing 15 are arranged on the pump shaft 33, the front main bearing 9 is fixedly connected to the front bearing body 8; the rear main bearing 15 is fixedly connected to the rear bearing body 18; the auxiliary sliding bearing assembly 5 is fixedly connected to the connecting section 6.

[0052] The balanced axial force unit includes: a balance ring 20, a balance disk 21 and an outer shell 22; the balance disk 21 is fixed to the end of the pump shaft 33, and a balance hole is opened in the center of the pump shaft 33; the balance ring 20 is fixed on the balance disk 21; the outer shell 22 is connected to the shielded motor unit (motor housing rear cover 16) with a stud 34, and the outer shell 22 is also connected to the heat exchanger unit, specifically, the outer shell 22 is connected to the medium inlet heat exchanger circulation pipe 28 and the balanced axial force circulation pipe 29 of the heat exchanger unit.

[0053] The heat exchanger unit includes: a heat exchanger body 25, a medium inlet heat exchanger circulation pipe 28, a medium outlet heat exchanger circulation pipe 26 and a balanced axial force circulation pipe 29; the heat exchanger body 25 is connected with the medium outlet heat exchanger circulation pipe 26 and the balanced axial force circulation pipe 29 through the medium inlet heat exchanger circulation pipe 28.

[0054] The metering pump unit is connected to the heat exchanger unit. The metering pump unit includes: a metering pump 31 and a safety valve 30; the metering pump 31 is connected to the heat exchanger body 25 through the medium inlet heat exchanger circulation pipe 28. The metering pump 31 has a metering pump inlet 32, which is used to connect to the user's clean medium source (clean medium without particles). The outlet of the safety valve 30 is connected to the metering pump inlet 32.

[0055] The specific working process of the utility model is as follows: In order to resist the wear of the medium containing solid particles, ensure that the pair of main bearings (front main bearing 9, rear main bearing 15), stator shielding sleeve 13, and rotor shielding sleeve 12 of the shielded motor unit are not damaged by the wear of the medium containing particles, and cool the shielded motor, a heat exchanger unit is installed on the upper part of the shielded motor unit, and the heat exchanger unit is connected to the metering pump unit. An exhaust device is installed on the upper part of the heat exchanger unit, and the metering pump inlet 32 ​​is connected to the user's clean medium without particles. See Figure 1-3 In the circulation 1○, when the pump is turned on, first open the metering pump 32 to allow the clean medium to fill the shielded pump, ensure that the pair of main bearings (front main bearing 9, rear main bearing 15), stator shielding sleeve 13, and rotor shielding sleeve 12 of the motor are filled with clean, particle-free medium, and then open the inlet and outlet valves of the shielded pump. When the shielded pump is running, the clean medium entering the connecting section 6 is pressurized by the auxiliary impeller 7 and passes through the gap between the stator shielding sleeve 13 and the rotor shielding sleeve 12, and enters the medium inlet heat exchanger circulation pipe 28 through the circulation hole A of the rear bearing body 18, and merges with the outlet of the metering pump 31 through the medium inlet heat exchanger circulation pipe 28 to enter the heat exchanger body 25. This part of the medium absorbs the heat generated by the shielded motor unit, and after cooling through the heat exchanger body 25, it re-enters the connecting section 6 through the medium outlet heat exchanger circulation pipe 26 and re-enters the auxiliary impeller 7 to keep reciprocating. The pressure of this part of the cycle is higher than the pressure of the pump head unit cavity, so the clean particle-free medium will pass through the auxiliary bearing 5, ensuring that the particle medium will not enter the motor cavity and damage the main bearing, stator shielding sleeve 13, and rotor shielding sleeve 12. At the same time, the motor is cooled to ensure long-term stable operation of the motor.

[0056] At present, the main axial force of the shielded pump conveying granular media is balanced by the pressure chamber formed by the impeller 2, the balancing hole D on the impeller and the wear-resistant plate 3. The axial force is greatly affected by the gap formed by the impeller 2 and the wear-resistant plate 3. In order to ensure that the entire shielded pump can still maintain axial force balance after the gap between the impeller 2 and the wear-resistant plate 3 increases due to the wear of the granular medium and affects the axial force, a balancing axial force unit is installed at the rear of the shielded motor unit. Figure 1-3In the circulation 2○, the clean medium is cooled by the heat exchanger body 25 and enters the pressure chamber formed by the balance ring seat 19 and the balance ring 20 through the balance axial force circulation pipe 29 and the circulation hole B of the rear bearing body 18, and enters the pressure chamber at the rear of the balance disk 21 through the gap between the balance ring seat 19 and the balance ring 20. The pressure chamber at the rear of the balance disk 21 is connected with the circulation hole in the center of the pump shaft 33. Through the circulation hole and the circulation hole C in the center of the pump shaft 33, the axial force to be balanced can be returned to the inlet of the auxiliary impeller 7 or the inlet of the impeller 2 according to the size of the axial force to be balanced. Since the pressures of the pressure chambers before and after the balance disk 21 are different, the balance disk can move slightly left and right in the pump chamber to dynamically balance the axial force. Therefore, the utility model can achieve that the axial force of the shielded pump remains balanced when the gap between the impeller and the wear-resistant plate contains granular media.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in the field should understand that modifying the technical solutions recorded in the aforementioned embodiments, or replacing part or all of the technical features therein by equivalents, does not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A canned motor pump with a balanced axial force unit, characterized in that: include: A pump shaft (33), a pump head unit, a shielded motor unit, a balanced axial force unit, a heat exchanger unit, and a metering pump unit; The pump shaft (33) passes through the pump head unit, the shielded motor unit and the balanced axial force unit; The pump head unit comprises: a pump body (1) and an impeller (2); the impeller (2) is arranged in the pump body (1), and the impeller (2) is fixed to the front end of the pump shaft (33); The shielded motor unit comprises: a stator assembly and a rotor (11); the stator assembly comprises a motor housing front cover (10), a motor housing (24), a stator (23) and a motor housing rear cover (16); the motor housing front cover (10) and the motor housing rear cover (16) are respectively arranged at two ends of the motor housing (24), and the stator (23) is arranged inside the motor housing (24); the rotor (11) is arranged on a pump shaft (33) and is located inside the stator (23); The balanced axial force unit comprises: a balance ring (20), a balance disk (21) and an outer shell (22); the balance disk (21) is fixed to the end of a pump shaft (33), and a balance hole is opened at the center of the pump shaft (33); the balance ring (20) is fixed to the balance disk (21); the outer shell (22) is connected to a shielded motor unit, and the outer shell (22) is also connected to a heat exchanger unit; The metering pump unit is connected to the heat exchanger unit.

2. The canned motor pump with a balanced axial force unit according to claim 1, characterized in that: The pump body (1) is connected to the shielded motor unit via a connecting section (6); The connecting section (6) is connected to the shielded motor unit via a through-bar (27); An auxiliary bearing (5) and an auxiliary impeller (7) are installed inside the connecting section (6); The connecting section (6) is provided with a circulation hole for connecting with the heat exchanger unit.

3. The canned motor pump with a balanced axial force unit according to claim 2, characterized in that: The pump head unit further comprises: a wear-resistant plate (3) and a mouth ring (4); The wear-resistant plate (3) is fixedly connected to the connecting section (6); and the mouth ring (4) is mounted on the pump body.

4. The canned motor pump with a balanced axial force unit according to claim 1, characterized in that: A stator shielding sleeve (13) is embedded inside the stator assembly, and the stator shielding sleeve (13) is welded to stator shielding plates (17) at both ends of the motor housing front cover (10) and the motor housing rear cover (16) respectively; The outer circumference of the rotor (11) is inlaid with a rotor shielding sleeve (12), the rotor shielding sleeve (12) is welded to rotor shielding plates (14) inlaid at both ends of the rotor (11), and the rotor shielding plates (14) are welded to the pump shaft (33); There is a gap between the stator shielding sleeve (13) and the rotor shielding sleeve (12).

5. The canned motor pump with a balanced axial force unit according to claim 1, characterized in that: The front end of the shielded motor unit is mounted with a front bearing body (8), and the rear end is mounted with a rear bearing body (18); The front bearing body (8) has a circulation hole, and the rear bearing body (18) has two circulation holes; The two circulation holes of the rear bearing body (18) are respectively connected to a medium inlet heat exchanger circulation pipe (28) and a balanced axial force circulation pipe (29); The rear bearing body (18) is fixed to the motor housing rear cover (16) by the outer housing (22).

6. The canned motor pump with a balanced axial force unit according to claim 5, characterized in that: A balance ring seat (19) is fixed on the rear bearing body (18), and a balance ring (20) is arranged on the balance ring seat (19); The balancing ring (20) is fixed on the balancing disk (21); the balancing disk (21) is key-connected to the pump shaft (33).

7. The canned motor pump with a balanced axial force unit according to claim 2, characterized in that: A front main bearing (9), a rear main bearing (15) and a set of auxiliary bearings (5) are installed inside the canned motor unit; The front main bearing (9) and the rear main bearing (15) are arranged on the pump shaft (33); the front main bearing (9) is fixedly connected to the front bearing body (8); and the rear main bearing (15) is fixedly connected to the rear bearing body (18); The auxiliary bearing (5) is fixedly connected to the connecting section (6).

8. The canned motor pump with a balanced axial force unit according to claim 1, characterized in that: The pump shaft (33) is provided with a circulation hole.

9. The canned motor pump with a balanced axial force unit according to claim 1, characterized in that: The heat exchanger unit comprises: a heat exchanger body (25), a medium inlet heat exchanger circulation pipe (28), a medium outlet heat exchanger circulation pipe (26) and a balanced axial force circulation pipe (29); The heat exchanger body (25) is connected to the medium heat exchanger outlet circulation pipe (26) and the balancing axial force circulation pipe (29) via the medium heat exchanger inlet circulation pipe (28).

10. The canned motor pump with a balanced axial force unit according to claim 9, characterized in that: The metering pump unit comprises: a metering pump (31) and a safety valve (30); The metering pump (31) is connected to the heat exchanger body (25) via a medium inlet heat exchanger circulation pipe (28).

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