Magnetic suspension shield pump system and axial force testing method thereof

Abstract

The invention discloses a magnetic suspension shield pump system and an axial force testing method thereof, and relates to a shield pump system and an axial force testing method thereof. The problems that a bearing of a traditional shield pump is short in service life and loud in noise in the working process, and an existing shield pump axial force testing method is low in precision are solved. The device comprises a top cover, a thrust disc assembly, an eddy current position sensor, a flange, an upper radial magnetic suspension bearing, a shielding motor stator, a shielding motor rotor, a lower radial magnetic suspension bearing, an impeller and a shaft. The thrust disc assembly and the upper radial magnetic suspension bearing sequentially sleeve the upper end of the shaft from top to bottom, the shielding motor stator and the shielding motor rotor sequentially sleeve the middle of the shaft from outside to inside, the lower radial magnetic suspension bearing and the impeller sequentially sleeve the lower end of the shaft from top to bottom, and the flange sleeves the thrust disc assembly and the upper radial magnetic suspension bearing. The top cover is fixedly connected with the upper surface of the flange, and the eddy current position sensor is installed on the flange. The invention belongs to the technical field of magnetic suspension shield pumps.

Description

Technical Field

[0001] The present invention relates to a canned motor pump system and an axial force testing method thereof, belonging to the technical field of magnetic levitation canned motor pumps. Background Art

[0002] Traditional canned motor pumps mostly adopt mechanical bearings, which generate a water film during operation to reduce bearing wear, but the effect is not good, resulting in low bearing life and high noise during the working process. The magnetic levitation canned motor pump is a new type of canned motor pump that applies magnetic levitation bearings to the canned motor pump, having the advantages of no wear, low vibration, and long life. The testing methods for the axial force of canned motor pumps are mainly the direct measurement method and the simulation calculation method. The direct measurement method is to directly measure the axial force by installing a tension-compression sensor on the pump shaft and performing dynamic sealing when the rotor shaft system rotates. This method requires installing a sensor on the pump shaft, which has a certain impact on the structure and performance of the pump, and the installation and debugging are complex, and the accuracy of the axial force test result is not high. The simulation calculation method is to establish a mathematical model of the magnetic levitation canned motor pump and use computer simulation to calculate the axial force. The advantage of this method is that it does not require actual testing and can quickly obtain an estimated value of the axial force. The disadvantage is that it is difficult to ensure the accuracy of the simulation model, and there may be a large deviation between the calculation result and the actual value. Summary of the Invention

[0003] In order to solve the problems of low bearing life and high noise during the working process of traditional canned motor pumps, as well as the low accuracy of the existing axial force testing methods for canned motor pumps, the present invention further provides a magnetic levitation canned motor pump system and an axial force testing method thereof.

[0004] The technical solution adopted by the present invention to solve the above problems is that a magnetic levitation canned motor pump system described in the present invention includes a top cover, a thrust disc assembly, an eddy current position sensor, a flange, an upper radial magnetic levitation bearing, a canned motor stator, a canned motor rotor, a lower radial magnetic levitation bearing, an impeller, and a shaft;

[0005] The thrust disc assembly and the upper radial magnetic levitation bearing are sequentially sleeved on the upper end of the shaft from top to bottom. The canned motor stator and the canned motor rotor are sequentially sleeved on the middle part of the shaft from outside to inside. The lower radial magnetic levitation bearing and the impeller are sequentially sleeved on the lower end of the shaft from top to bottom. The flange is sleeved on the thrust disc assembly and the upper radial magnetic levitation bearing. The top cover is fixedly connected to the upper surface of the flange. The eddy current position sensor is installed on the flange.

[0006] Further, the thrust disc assembly includes an upper axial stator, a thrust disc, and a lower axial stator;

[0007] The upper axial stator, the thrust disc, and the lower axial stator are sequentially sleeved on the upper end of the shaft from top to bottom.

[0008] Further, the upper radial magnetic levitation bearing includes an upper radial magnetic levitation bearing rotor and an upper radial magnetic levitation bearing stator;

[0009] The upper radial magnetic levitation bearing rotor is sleeved on the upper end of the shaft, and the upper radial magnetic levitation bearing stator is sleeved on the upper radial magnetic levitation bearing rotor.

[0010] Furthermore, the lower radial magnetic levitation bearing includes a lower radial magnetic levitation bearing stator and a lower radial magnetic levitation bearing rotor;

[0011] The lower radial magnetic levitation bearing rotor is sleeved on the lower end of the shaft, and the lower radial magnetic levitation bearing stator is sleeved on the lower radial magnetic levitation bearing rotor.

[0012] Furthermore, it also includes an upper protection bearing and a lower protection bearing;

[0013] The upper protection bearing is sleeved on the upper part of the shaft, and the upper protection bearing is located between the upper radial magnetic levitation bearing and the shield motor rotor. The lower protection bearing is sleeved on the lower part of the shaft, and the lower protection bearing is located between the shield motor rotor and the lower radial magnetic levitation bearing.

[0014] Furthermore, a flange is also sleeved on the lower radial magnetic levitation bearing, and an eddy current position sensor is inserted on the flange.

[0015] The steps of the axial force test method for a magnetic levitation canned motor pump system according to the present invention include:

[0016] Step 1: The canned motor pump is not filled with water, the shaft ends of the rotor shaft system are exposed, the magnetic levitation bearings work to make the rotor shaft system float at the central positions in the radial and axial directions respectively. The initial weight of the rotor shaft system is known, and the magnitude of the control current at this time is recorded; within the bearing capacity range of the axial magnetic levitation bearing, upward and downward axial forces are respectively applied to the rotor shaft system by applying a tensile force at the shaft end, and the relationship curve between the control current ix of the axial magnetic levitation bearing and the sum F of the rotor shaft system weight and the applied axial force is recorded;

[0017] Step 2: Within the axial movement range of the rotor shaft system, change the axial floating position of the rotor shaft system, and repeat the measurement of the relationship curve between the control current ix of the axial magnetic levitation bearing and the sum F of the rotor shaft system weight and the applied axial force;

[0018] Step 3: Seal the canned motor pump system with magnetic levitation bearings and connect the pipeline;

[0019] The radial magnetic levitation bearing always suspends the rotor shaft system at the radial central position. When the canned motor pump operates at different speeds, the rotor shaft system is controlled at different axial positions by the axial magnetic levitation bearing. Look up the table according to the relationship curve between the control current ix of the axial magnetic levitation bearing and the axial position and the sum F of the axial forces of the rotor shaft system obtained in Step 1 and Step 2, and then subtract the weight and buoyancy of the rotor shaft system to obtain the axial force of the canned motor pump at different speeds and different axial positions.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The present invention adopts non-contact axial force measurement, without installing sensors and dynamic seals on the shaft, and the measurement accuracy of the axial force is very high;

[0022] 2. For canned motor pumps with magnetic levitation bearings, the axial force measurement method described in the present invention can be directly used for axial force measurement. For ordinary canned motor pumps without magnetic levitation bearings, magnetic levitation bearings can be installed at both ends of the canned motor to test the axial force, and only the port connection method and the installation of the magnetic levitation bearing rotor need to be considered.

[0023] 3. The magnetic levitation bearing can effectively reduce the vibration of the canned motor pump system, reduce the vibration and noise of the canned motor pump system, and greatly improve the stability, repeatability and accuracy of axial force measurement;

[0024] 4. The magnetic levitation bearing has no wear, greatly improves the service life of the canned motor pump, and saves the maintenance cost of disassembling and replacing the bearing of the traditional canned motor pump;

[0025] 5. When the magnetic levitation bearing is running, it is convenient, fast and accurate to change the suspension position of the rotor shafting, and the axial force at any position within the movement range of the rotor shafting can be measured, which is convenient to find the best working point of the canned motor pump. Description of the Drawings

[0026] Figure 1 is a cross-sectional view of the magnetic levitation canned motor pump system;

[0027] Figure 2 is a cross-sectional view of the rotor shafting of the magnetic levitation canned motor pump system;

[0028] Figure 3 is a flowchart of axial force measurement of the magnetic levitation canned motor pump system;

[0029] Figure 4 is a control schematic diagram of the magnetic levitation bearing;

[0030] Figures 1 to 4 In the figure, 1 - top cover, 2 - upper axial stator, 3 - thrust disk, 4 - lower axial stator, 5 - eddy current position sensor, 6 - flange, 7 - upper radial magnetic levitation bearing rotor, 8 - upper radial magnetic levitation bearing stator, 9 - upper protection bearing, 1,0 - canned motor stator, 1,1 - canned motor rotor, 1,2 - lower protection bearing, 1,3 - lower radial magnetic levitation bearing stator, 1,4 - lower radial magnetic levitation bearing rotor, 1,5 - impeller, 1,6 - shaft. Detailed Embodiments

[0031] Detailed Embodiment 1: As Figure 1As shown in the figure, a magnetic levitation canned motor pump system includes a top cover 1, a thrust disc assembly, an eddy current position sensor 5, a flange 6, an upper radial magnetic levitation bearing, a canned motor stator 10, a canned motor rotor 11, a lower radial magnetic levitation bearing, an impeller 15, and a shaft 16;

[0032] The thrust disc assembly and the upper radial magnetic levitation bearing are successively sleeved on the upper end of the shaft 16 from top to bottom. The canned motor stator 10 and the canned motor rotor 11 are successively sleeved on the middle part of the shaft 16 from outside to inside. The lower radial magnetic levitation bearing and the impeller 15 are successively sleeved on the lower end of the shaft 16 from top to bottom. The flange 6 is sleeved on the thrust disc assembly and the upper radial magnetic levitation bearing. The top cover 1 is fixedly connected to the upper surface of the flange 6. The eddy current position sensor 5 is installed on the flange 6.

[0033] In order to improve the measurement accuracy, an eddy current position sensor 5 is also installed on the top cover 1.

[0034] A flange 6 is also sleeved on the lower radial magnetic levitation bearing, and an eddy current position sensor 5 is inserted on the flange 6.

[0035] Among them, the thrust disc assembly includes an upper axial stator 2, a thrust disc 3, and a lower axial stator 4;

[0036] The upper axial stator 2, the thrust disc 3, and the lower axial stator 4 are successively sleeved on the upper end of the shaft 16 from top to bottom.

[0037] Among them, the upper radial magnetic levitation bearing includes an upper radial magnetic levitation bearing rotor 7 and an upper radial magnetic levitation bearing stator 8;

[0038] The upper radial magnetic levitation bearing rotor 7 is sleeved on the upper end of the shaft 16, and the upper radial magnetic levitation bearing stator 8 is sleeved on the upper radial magnetic levitation bearing rotor 7.

[0039] Among them, the radial magnetic levitation bearing includes a lower radial magnetic levitation bearing stator 13 and a lower radial magnetic levitation bearing rotor 14;

[0040] The lower radial magnetic levitation bearing rotor 14 is sleeved on the lower end of the shaft 16, and the lower radial magnetic levitation bearing stator 13 is sleeved on the lower radial magnetic levitation bearing rotor 14.

[0041] Specific Embodiment 2: As Figure 1 shown, it further includes an upper protective bearing 9 and a lower protective bearing 12;

[0042] The upper protective bearing 9 is sleeved on the upper part of the shaft 16, and the upper protective bearing 9 is located between the upper radial magnetic levitation bearing and the canned motor rotor 11. The lower protective bearing 12 is sleeved on the lower part of the shaft 16, and the lower protective bearing 12 is located between the canned motor rotor 11 and the lower radial magnetic levitation bearing.

[0043] Specific Embodiment 3: As Figures 1 to 4As shown, a method for testing the axial force of a magnetic levitation canned motor pump system, the specific steps include:

[0044] Step 1: The canned motor pump is not filled with water, the shaft end of the rotor shafting is exposed, the magnetic levitation bearing operates to suspend the rotor shafting at the central positions in the radial and axial directions respectively, the initial weight of the rotor shafting is known, and the magnitude of the control current at this time is recorded; within the bearing capacity range of the axial magnetic levitation bearing, upward and downward axial forces are respectively applied to the rotor shafting by applying a tensile force at the shaft end, and the relationship curve between the control current ix of the axial magnetic levitation bearing and the sum F of the weight of the rotor shafting and the applied axial force is recorded.

[0045] Step 2: Within the axial movement range of the rotor shafting, change the axial suspension position of the rotor shafting, and repeat the measurement of the relationship curve between the control current ix of the axial magnetic levitation bearing and the sum F of the weight of the rotor shafting and the applied axial force.

[0046] Step 3: Seal the canned motor pump system with a magnetic levitation bearing and connect the pipeline.

[0047] The radial magnetic levitation bearing always suspends the rotor shafting at the radial central position. When the canned motor pump operates at different speeds, the rotor shafting is controlled at different axial positions by the axial magnetic levitation bearing. Look up the relationship curve between the control current ix of the axial magnetic levitation bearing and the axial position and the sum F of the axial forces of the rotor shafting obtained in Step 1 and Step 2, and then subtract the weight and buoyancy of the rotor shafting to obtain the axial force of the canned motor pump at different speeds and different axial positions.

[0048] The above is only a preferred embodiment of the present invention, and does not impose any form of limitation on the present invention. Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to the equivalent embodiments by using the disclosed technical content within the scope of the technical solution of the present invention. However, as long as it does not depart from the content of the technical solution of the present invention, any simple modification, equivalent replacement, and improvement made to the above embodiments according to the technical essence of the present invention within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A magnetic levitation canned motor pump system, characterized in that, It includes a top cover (1), a thrust disc assembly, an eddy current position sensor (5), a flange (6), an upper radial magnetic levitation bearing, a canned motor stator (10), a canned motor rotor (11), a lower radial magnetic levitation bearing, an impeller (15) and a shaft (16); The thrust disc assembly and the upper radial magnetic levitation bearing are sleeved on the upper end of the shaft (16) in sequence from top to bottom. The canned motor stator (10) and the canned motor rotor (11) are sleeved on the middle part of the shaft (16) in sequence from outside to inside. The lower radial magnetic levitation bearing and the impeller (15) are sleeved on the lower end of the shaft (16) in sequence from top to bottom. The flange (6) is sleeved on the thrust disc assembly and the upper radial magnetic levitation bearing. The top cover (1) is fixedly connected to the upper surface of the flange (6). The eddy current position sensor (5) is installed on the flange (6).

2. The magnetic levitation canned motor pump system according to claim 1, characterized in that, The thrust disc assembly includes an upper axial stator (2), a thrust disc (3) and a lower axial stator (4); The upper axial stator (2), the thrust disc (3) and the lower axial stator (4) are sleeved on the upper end of the shaft (16) in sequence from top to bottom.

3. The maglev canned motor pump system according to claim 1, wherein, The upper radial magnetic levitation bearing includes an upper radial magnetic levitation bearing rotor (7) and an upper radial magnetic levitation bearing stator (8); The upper radial magnetic levitation bearing rotor (7) is sleeved on the upper end of the shaft (16), and the upper radial magnetic levitation bearing stator (8) is sleeved on the upper radial magnetic levitation bearing rotor (7).

4. A magnetic levitation canned motor pump system according to claim 1, wherein The lower radial magnetic levitation bearing includes a lower radial magnetic levitation bearing stator (13) and a lower radial magnetic levitation bearing rotor (14); The lower radial magnetic levitation bearing rotor (14) is sleeved on the lower end of the shaft (16), and the lower radial magnetic levitation bearing stator (13) is sleeved on the lower radial magnetic levitation bearing rotor (14).

5. A magnetic levitation canned motor pump system according to claim 1, characterized in that, It also includes an upper protective bearing (9) and a lower protective bearing (12); The upper protective bearing (9) is sleeved on the upper part of the shaft (16), and the upper protective bearing (9) is located between the upper radial magnetic levitation bearing and the canned motor rotor (11). The lower protective bearing (12) is sleeved on the lower part of the shaft (16), and the lower protective bearing (12) is located between the canned motor rotor (11) and the lower radial magnetic levitation bearing.

6. The magnetic levitation canned motor pump system according to claim 1, wherein A flange (6) is also sleeved on the lower radial magnetic levitation bearing, and an eddy current position sensor (5) is inserted on the flange (6).

7. A method for testing the axial force of a magnetic levitation canned motor pump system, characterized in that, The specific steps include: Step 1: The canned pump is not filled with water, the shaft end of the rotor shafting is exposed, the magnetic levitation bearing works to make the rotor shafting suspended at the central positions in the radial and axial directions respectively. The initial weight of the rotor shafting is known, and the magnitude of the control current at this time is recorded. Within the bearing capacity range of the axial magnetic levitation bearing, axial forces in the upward and downward directions are respectively applied to the rotor shafting by applying a tensile force at the shaft end, and the relationship curve between the control current ix of the axial magnetic levitation bearing and the sum F of the rotor shafting weight and the applied axial force is recorded; Step 2: Within the axial movement range of the rotor shafting, the axial suspension position of the rotor shafting is changed, and the relationship curve between the control current ix of the axial magnetic levitation bearing and the sum F of the rotor shafting weight and the applied axial force is repeatedly measured; Step 3: Seal the canned pump system with the magnetic levitation bearing and connect the pipeline; The radial magnetic levitation bearing always suspends the rotor shafting at the radial center position. When the canned motor pump operates at different speeds, the rotor shafting is controlled at different axial positions by the axial magnetic levitation bearing. Look up the relationship curve between the control current ix of the axial magnetic levitation bearing obtained according to Step 1 and Step 2 and the sum F of the axial position and axial force of the rotor shafting, and then subtract the weight and buoyancy of the rotor shafting to obtain the axial force of the canned motor pump at different speeds and different axial positions.

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