Easily-vaporized internal supercharging type shielding electric pump structure
By adding a secondary impeller to the rear chamber of the pump and changing the circulation method of the pump, the cavitation problem in the rear chamber of the reverse circulation shielded pump is solved, effective boosting of the rear chamber pressure and media flow are achieved, and the cavitation risk is reduced.
Patent Information
- Application Number
- CN202421722310.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-07-19
AI Technical Summary
The existing reverse circulation shielding pumps have cavitation problems in the rear cavity, and the existing improvement solutions are mainly concentrated at the main impeller, and there is a lack of effective improvement methods at the rear reverse circulation.
Add a secondary impeller to the rear chamber of the pump, change the circulation method of the internal supercharged shielded electric pump, add a small cycle, and supercharge the rear chamber through the secondary impeller to solve the problem of lowering the pressure of the rear chamber.
By increasing the secondary impeller, the pressure in the rear cavity is effectively increased, the cavitation phenomenon is reduced, and the flow path of the medium is optimized, the residence time of the medium in the pump is reduced, and the cavitation risk is further reduced.
Smart Images
Figure CN223035272U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electric pumps, and particularly relates to a vaporization-prone internal pressurization type canned motor pump structure. Background Technique
[0002] Cavitation is extremely likely to occur when the pressure of the container decreases and the temperature rises. For vaporization-prone media, a vertical reverse circulation structure is usually selected. For a reverse circulation structure canned motor pump, cavitation not only occurs at the main impeller, but also occurs near the reverse circulation flange at the rear cavity.
[0003] As shown in Figure 1, the existing medium circulation mode of the reverse circulation type canned motor pump is as follows:
[0004] One part is: the pump body inlet → impeller → pump body outlet;
[0005] Another part is: the pump body inlet → impeller → FB end cover circulation hole → between the stator and rotor sleeves → RB end cover circulation hole / between the bearing and the RB end cover → reverse circulation flange.
[0006] Since the motor stator and rotor itself generate heat during operation, the temperature of the internal circulating liquid will rise when passing between the stator and rotor sleeves. When running to the rear RB end cover, due to the existence of the reverse circulation flange port, the pressure decreases, so cavitation occurs.
[0007] However, at present, there are mainly solutions to improve cavitation at the main impeller, and there is no effective improvement method at the rear reverse circulation part. Content of the Utility Model
[0008] The purpose of the utility model is to overcome the above-mentioned problems and provide a vaporization-prone internal pressurization type canned motor pump structure.
[0009] The technical solution adopted by the utility model to achieve the above purpose is as follows:
[0010] A vaporization-prone internal pressurization type canned motor pump structure includes a pump body and a motor connected to the pump body. FB end covers and RB end covers are respectively installed at the front and rear ends of the rotating shaft of the motor. An impeller is installed at the front end of the rotating shaft located at the FB end cover. The impeller is arranged in the pump cavity of the pump body. The outlet of the pump body is communicated with the RB end cover circulation hole on the RB end cover through an external circulation pipeline. A rear bearing is installed between the rear end of the rotating shaft and the RB end cover. A secondary impeller is installed at the front end of the rotating shaft located at the rear of the rear bearing. A rear shaft head circulation hole is opened at the rear end of the rotating shaft. One end of the rear shaft head circulation hole is communicated with the RB end cover circulation hole, and the other end is communicated with the secondary impeller.
[0011] The secondary impeller is located at the rear end of the rotor of the motor and is key-connected to the rotating shaft.
[0012] The rear bearing set is installed on the rear bearing housing, and the rear bearing housing is installed on the RB end cover.
[0013] The characteristics of the present utility model are as follows: by adding a secondary impeller to the rear cavity of the pump, the circulation mode of the internally pressurized canned motor pump is changed, a small circulation is added, and the rear cavity is pressurized by the secondary impeller, so as to solve the problem of the reduction of the rear cavity pressure and reduce cavitation. Description of the Drawings
[0014] Figure 1 It is a schematic diagram of the circulation structure of the existing reverse circulation pump.
[0015] Figure 2 It is a schematic diagram of the structure of the present utility model.
[0016] Figure 3 It is a schematic diagram of the structure at the secondary impeller of the present utility model.
[0017] Wherein: 1. Pump body; 11. Inlet; 12. Outlet; 2. Motor; 21. Rotating shaft; 211. Rear end head circulation hole; 22. Rear bearing; 23. Rear bearing housing; 24. Rotor; 3. FB end cover; 4. RB end cover; 41. RB end cover circulation hole; 5. Impeller; 6. Outer circulation pipeline; 7. Secondary impeller. Specific Embodiments
[0018] As Figure 2-3 shown, the present utility model is a structure of an internally pressurized canned motor pump prone to vaporization, including a pump body 1 and a motor 2 connected to the pump body 1. FB end cover 3 and RB end cover 4 are respectively installed at the front and rear ends of the rotating shaft 21 of the motor 2. An impeller 5 is installed at the front end of the rotating shaft 21 located in front of the FB end cover 3. The impeller 5 is arranged in the pump cavity of the pump body 1. The outlet 12 of the pump body 1 is communicated with the RB end cover circulation hole 41 on the RB end cover 4 through an outer circulation pipeline. A rear bearing 22 is installed between the rear end of the rotating shaft 21 and the RB end cover 4. The rear bearing 22 is sleeved on the rear bearing housing 23, and the rear bearing housing 23 is installed on the RB end cover 4. A secondary impeller 7 is installed at the front end of the rotating shaft 21 located behind the rear bearing 22. The secondary impeller 7 is located at the rear cover plate of the rotor 24 of the motor 2 and is key-connected to the rotating shaft 21. A rear shaft head circulation hole 211 is opened at the rear end of the rotating shaft 21. One end of the rear shaft head circulation hole 211 is communicated with the RB end cover circulation hole 41, and the other end is communicated with the secondary impeller 7.
[0019] The present utility model changes the circulation mode of the internally pressurized canned motor pump by adding a secondary impeller 7 to the rear cavity of the pump, specifically as follows:
[0020] A part of the medium: flows into the impeller 5 through the inlet 11 of the pump body 1 and then is discharged through the outlet 12 of the pump body 1;
[0021] Another part of the medium: It flows into the impeller 5 through the inlet 11 of the pump body 1 and then flows into the external circulation pipeline 6 through the outlet 12 of the pump body 1. Then it flows into the auxiliary impeller 7 through the RB end cover circulation hole 41 and the rear shaft head circulation hole 211. The medium running here is divided into two steps: One part runs between the stator and rotor sleeves of the motor 2 to the FB end cover 3 and is discharged from the outlet 12 of the pump body 1 through the circulation hole of the FB end cover 3; Another part runs between the rear bearing 22 and the RB end cover 4 or between the rear bearing 22 and the rear bearing seat 23 to the rear shaft head circulation hole 211, and the medium then runs to the lower part of the auxiliary impeller 7. The overall running rule of the medium is to run from the RB end cover 4 towards the pump body side.
[0022] The utility model adds an auxiliary impeller 7 to the rear cavity of the pump, so that a small circulation is added to the rear cavity of the internally pressurized canned motor pump. A rear shaft head circulation hole 211 is added at the rear end of the rotating shaft 21 and extends to the lower part of the auxiliary impeller 7, so that a part of the medium is led to the lower part of the auxiliary impeller 7 through the rear shaft head circulation hole 211, and the rear cavity is pressurized by the auxiliary impeller 7, thus solving the problem that the pressure of the rear cavity will decrease. Moreover, when the medium runs, a part of the medium that should originally flow towards the pump body 1 between the stator and rotor sleeves of the motor 2 can only flow towards the RB end cover 4 due to the high pressure in the front cavity, thereby increasing the pressure and reducing cavitation; Another part of the medium flows out from the auxiliary impeller 7 and directly flows towards the RB end cover 4, which can play a role in promoting the medium, enabling the medium to pass through at an accelerated speed and minimizing the residence time of the medium here, thereby achieving the effect of reducing cavitation generated by the medium in the pump.
[0023] In specific applications, the increased pressure of the auxiliary impeller 7 on the rear cavity needs to be controlled. Therefore, the size of the impeller 5 in the front cavity is increased, and the number of circulation holes in the FB end cover 3 needs to be doubled, so that the pressure generated by the medium in the front cavity is transmitted to the rear cavity to the maximum extent.
[0024] The above is only the preferred specific implementation manner of the utility model, but the protection scope of the utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution of the utility model and its inventive concept, makes equivalent substitutions or changes, and should be covered within the protection scope of the utility model.
Claims
1. An easily vaporizable internally pressurized canned motor pump structure, comprising a pump body and a motor connected to the pump body, characterized in that: The front and rear ends of the rotating shaft of the motor are respectively installed with FB end covers and RB end covers. The rotating shaft is installed with an impeller at the front end of the FB end cover. The impeller is arranged in the pump cavity of the pump body. The outlet of the pump body is connected with the RB end cover circulation hole on the RB end cover through an external circulation pipeline. A rear bearing is installed between the rear end of the rotating shaft and the RB end cover. The rotating shaft is installed with an auxiliary impeller at the front end of the rear bearing. A rear shaft head circulation hole is opened at the rear end of the rotating shaft. One end of the rear shaft head circulation hole is connected with the RB end cover circulation hole, and the other end is connected with the auxiliary impeller.
2. The easily vaporizable internally pressurized canned motor pump structure according to claim 1, characterized in that: The auxiliary impeller is located at the rear end of the rotor of the motor and is keyed to the rotating shaft.
3. The easily vaporizable internally pressurized canned motor pump structure according to claim 1, characterized in that: The rear bearing is sleeved on the rear bearing seat, and the rear bearing seat is installed on the RB end cover.