A mechanical seal performance testing platform for pumps

Abstract

This invention belongs to the technical field of mechanical seal performance testing for nuclear power plant water pumps, specifically relating to a testing platform for pump mechanical seal performance. The mechanical seal under test is fitted with the shaft sleeve, shell sleeve, and housing in pairs via transition fits. The shell sleeve is secured by a mechanical seal gland and bolts. The non-drive shaft is connected to the drive shaft via a coupling and to the shaft sleeve and coupling via a key. The end cover is connected to the housing, the end cover is connected to the bearing bracket, and the housing is connected to the base. The mechanical seal connects the mechanical seal gland and the end cover to position the mechanical seal. The bearing and non-drive shaft are fitted with an interference fit. The bearing gland and bearing bracket are connected to secure the bearing. The coupling is fixed to both the pump side and the motor side via keys and the non-drive shaft, thus connecting the non-drive shaft and the drive shaft. The coupling is equipped with a coupling protective cover. The motor and base are connected. This invention can simulate the actual operating conditions of a nuclear power plant water pump, improving measurement accuracy and platform versatility.

Description

Technical Field

[0001] This invention belongs to the field of mechanical seal performance testing technology for nuclear power plant water pumps, and specifically relates to a mechanical seal performance testing platform for pumps. Background Technology

[0002] In nuclear power plants, the importance of mechanical seals for water pumps cannot be ignored. They rely on an end-face sealing pair perpendicular to the rotating shaft to maintain a tight seal and slide relative to each other under the combined action of fluid pressure and a compensation mechanism, effectively preventing fluid leakage. As the shaft sealing device for the water pump, the mechanical seal ensures stable operation of the pump under harsh environments such as high pressure, high temperature, and radiation. If the mechanical seal performance is poor, the risk of pump leakage will increase, which will not only interfere with the normal operation of the nuclear power plant but may also pose safety hazards. Therefore, the testing technology for mechanical seal performance requires extremely stringent standards.

[0003] Currently, traditional testing of mechanical seal performance in water pumps primarily relies on mechanical seal testing machines. While these machines possess some testing capabilities, they still present several challenges. First, nuclear power plant water pumps require extremely high mechanical seal performance, needing to maintain excellent sealing stability under extreme conditions (such as high temperature, high pressure, and strong radiation environments). Although mechanical seal testing machines can simulate some environmental conditions, they struggle to replicate the actual operating conditions of nuclear power plant water pumps, potentially affecting the accuracy of test results. Second, mechanical seal testing machines are mainly designed for specific sizes or types of mechanical seals and are generally incompatible with other sizes, exhibiting poor versatility. Finally, using mechanical seals that fail sealing tests can lead to wasted time and manpower on reassembly and disassembly, as well as risks such as radioactive wastewater leakage. Therefore, a novel performance testing platform for nuclear power plant water pump mechanical seals is urgently needed to effectively address these issues. Summary of the Invention

[0004] The purpose of this invention is to provide a pump mechanical seal performance testing platform that can meet the requirements for mechanical seal sealing performance testing of nuclear power plant water pumps, simulate the actual operating conditions of nuclear power plant water pumps, improve measurement accuracy and platform versatility, overcome the limitations of traditional testing methods, and avoid frequent on-site disassembly and assembly due to substandard mechanical seal performance, thereby significantly saving time, manpower and material costs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A pump mechanical seal performance testing platform is disclosed. The mechanical seal under test is connected to the shaft sleeve, housing sleeve, and housing in pairs via transition fits. The housing sleeve is secured by a mechanical seal gland and bolts. The non-drive shaft is connected to the drive shaft via a coupling and to the shaft sleeve and coupling via a key. The end cover is connected to the housing, the end cover is connected to the bearing bracket, and the housing is connected to the base. The mechanical seal connects the mechanical seal gland and the end cover to position the mechanical seal. The bearing and non-drive shaft are interference-fitted. The bearing gland and bearing bracket are connected to secure the bearing. The coupling is fixed to both the pump and motor sides via keys and the non-drive shaft, thus connecting the non-drive and drive shafts. The coupling is equipped with a coupling guard. The motor is connected to the base. The testing platform has horizontal radial input and vertical axial output water pipelines, and is equipped with an inlet valve, an outlet valve, an exhaust valve, an inlet pressure gauge, and an outlet pressure gauge. The inlet valve supplies water from the centrifugal pump outlet, giving the input medium a certain kinetic and pressure energy, thereby simulating the actual operating conditions of a centrifugal pump.

[0007] The non-drive shaft is a stepped shaft.

[0008] The end cap and the housing are connected by flanges.

[0009] The end cap is connected to the bearing bracket by bolt B.

[0010] The housing is connected to the base by bolt A.

[0011] The mechanical seal is an integrated mechanical seal.

[0012] The mechanical seal is connected to the end cap by bolt A.

[0013] The bearing cap and bearing housing are connected by bolt B.

[0014] The motor is a variable frequency motor and is connected to the base by bolt A.

[0015] Close the outlet valve; open the vent valve; open the inlet valve; start the inlet centrifugal pump to input the medium at a flow rate of 50% of the rated flow rate of the centrifugal pump corresponding to the mechanical seal under test, so that the cooling water fills the chamber, thereby venting the air in the chamber; after the chamber is vented, start the motor at a speed of 50% of the rated speed of the centrifugal pump corresponding to the mechanical seal under test; close the vent valve; gradually open the outlet valve, and after the operation is stable, slowly increase the valve opening until it is fully open, while constantly monitoring the outlet pressure gauge data during operation; maintain the 50% speed for 5 minutes, then increase the motor speed to 100%; maintain the 100% speed for 5 minutes, then increase the motor speed to 130%; adjust the motor speed to 100%, and increase the inlet centrifugal pump input flow rate to 100% of the rated flow rate; maintain this state for 5 minutes, then increase the inlet centrifugal pump input flow rate to 130% of the rated flow rate; maintain this state for 5 minutes. If there is no water leakage in the chamber, the mechanical seal performance is considered good; close the inlet and outlet valves, and disconnect the motor power supply; the operation is complete.

[0016] The beneficial effects achieved by this invention are as follows:

[0017] 1) High simulation realism. The design of this platform, the speed regulation of the variable frequency motor, and the inlet regulating valve make the mechanical seal closely resemble the actual operating conditions of a nuclear power plant water pump during the testing process.

[0018] 2) High versatility. Through the internal and external fit design of the bushing, housing, and mechanical seal, the platform can flexibly adapt to mechanical seals of different sizes, thereby greatly reducing testing costs and achieving efficient use of resources.

[0019] 3) High accuracy. Because the platform operates very closely to the actual operating conditions of nuclear power plant pumps and can provide different speeds and inlet flow rates, the accuracy of the test is improved.

[0020] 4) Intuitive test results. Traditional mechanical seal testing machines require a combination of bubble continuity and pressure gauge changes to judge the test results, while this platform only needs to observe whether there is water leakage to determine whether the mechanical seal has passed the test, greatly simplifying the judgment process.

[0021] 5) Reduced risk of repetitive maintenance. The use of this platform can improve the accuracy of mechanical seal performance testing and avoid the risk of repeated disassembly and assembly due to substandard mechanical seal sealing. Attached Figure Description

[0022] Figure 1 A schematic diagram of a performance testing platform for mechanical seals used in pumps;

[0023] In the diagram: 1-Mechanical seal under test; 2-Sleeve; 3-Mechanical seal cover; 4-Shell; 5-Shell; 6-Outlet valve; 7-Exhaust valve; 8-End cover; 9-Mechanical seal; 10-Bearing; 11-Bearing cover; 12-Coupling protective cover; 13-Elastic element; 14-Coupling; 15-Motor; 16-Key; 17-Bolt A; 18-Bearing bracket; 19-Non-drive shaft; 20-Drive shaft; 21-Bolt B; 22-Inlet valve; 23-Inlet and outlet water lines of the testing platform; LP1-Inlet pressure gauge; LP2-Outlet pressure gauge. Detailed Implementation

[0024] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0025] A pump mechanical seal performance testing platform includes: 1-the mechanical seal to be tested; 2-shaft sleeve; 3-mechanical seal gland; 4-shell sleeve; 5-shell; 6-outlet valve; 7-vent valve; 8-end cover; 9-mechanical seal; 10-bearing; 11-bearing gland; 12-coupling protective cover; 13-elastic element; 14-coupling; 15-motor; 16-key; 17-bolt A; 18-bearing bracket; 19-non-drive shaft; 20-drive shaft; 21-bolt B; 22-inlet valve; 23-inlet and outlet water pipelines of the testing platform; LP1-inlet pressure gauge; LP2-outlet pressure gauge.

[0026] The mechanical seal 1 under test is fitted with each of the machined bushing 2, housing 4, and housing 5 using a transition fit. The housing 4 is secured to the mechanical seal cover 3 and bolts. The non-drive shaft 19 is a stepped shaft, connected to the drive shaft 20 via coupling 14, and connected to the bushing 2 and coupling 14 via key 16. The end cover 8 and housing 5 are connected by a flange, and connected to the bearing bracket 18 via bolt B21. The housing 5 is connected to the base via bolt A17. The mechanical seal 9 is an integrated mechanical seal, secured to the mechanical seal cover 3 via bolt A17. The bearing 10 is connected to the end cover 8 to position the mechanical seal 9. The bearing 10 and the non-drive shaft 19 are fitted with an interference fit to bear the radial load of the device. The bearing cover 11 and the bearing bracket 18 are connected by bolt B21 to fix the bearing 10. The pump side and the motor side of the coupling 14 are fixed to the non-drive shaft 19 and the drive shaft 20 by key 16, thereby connecting the non-drive shaft 19 and the drive shaft 20. The motor 15 is a variable frequency motor, connected to the base by bolt A17 to adjust the speed of the device. The water inlet and outlet pipelines 23 of the detection platform are horizontal radial input and vertical axial output, and are equipped with an inlet valve 22, an outlet valve 6, an exhaust valve 7, and an inlet pressure gauge LP1 and an outlet pressure gauge LP2. The water supplied by the inlet valve 22 is the outlet water of the centrifugal pump, so that the input medium of the platform has a certain kinetic energy and pressure energy, thereby simulating the actual operating conditions of the centrifugal pump. The remaining pipelines are the bearing and mechanical seal cooling water pipelines, and the water supply comes from the cooling water tank. The coupling 14 is equipped with a coupling protective cover 12.

[0027] The method for testing the mechanical seal performance of a nuclear power plant pump is as follows: The inner diameter, outer diameter, and width of the mechanical seal 1 to be tested are measured. Based on the measurement data, it is assessed whether machining of the existing bushing 2 and housing 4 is necessary. Subsequently, the bearing components, hydraulic components, coupling, and motor are installed sequentially. The coupling is then aligned and adjusted, lubricating oil is added, and auxiliary pipelines are installed. After the platform assembly is complete, the outlet valve 6 is closed, the vent valve 7 is opened, and the inlet valve 22 is opened. After priming and venting, the motor is started. Once the unit is running stably, the outlet valve is gradually opened. The motor speed and inlet medium flow rate are adjusted via the motor and inlet valve to ultimately achieve the pump mechanical seal performance test. Specifically, the following steps are included:

[0028] 1) Measure the inner diameter, outer diameter and width of the mechanical seal 1 to be tested, and evaluate whether the existing bushing 2 and housing 4 need to be machined based on the measurement data;

[0029] 2) Install the bearing components, intact mechanical seal, hydraulic components, and mechanical seal to be tested in sequence to complete the installation of the test chamber;

[0030] 3) Then reinstall the coupling and motor, and perform coupling alignment adjustment, add lubricating oil, and install auxiliary pipelines and pressure gauges;

[0031] 4) Confirm that the cooling water tank flow rate is normal and ensure that the cooling water tank flow rate remains normal during subsequent platform operation;

[0032] 5) Close the outlet valve 6;

[0033] 6) Open the exhaust valve 7;

[0034] 7) Open inlet valve 22;

[0035] 8) Start the inlet centrifugal pump to input the medium (the flow rate is 50% of the rated flow rate of the centrifugal pump corresponding to the mechanical seal under test), so that the cooling water fills the chamber and the air in the chamber is discharged.

[0036] 9) After the chamber is vented, start the motor at 50% of the rated speed of the centrifugal pump corresponding to the mechanical seal under test;

[0037] 10) Close the exhaust valve 7;

[0038] 11) Gradually open outlet valve 6, and after ensuring stable platform operation, slowly increase the valve opening until it is fully open. At the same time, pay close attention to the outlet pressure gauge LP2 data during operation.

[0039] 12) Maintain 50% speed for about 5 minutes, then increase the motor speed to 100%;

[0040] 13) Maintain 100% speed for about 5 minutes, then increase the motor speed to 130%;

[0041] 14) Adjust the motor speed to 100% and increase the inlet centrifugal pump input flow rate to 100% of the rated flow rate;

[0042] 15) Maintain this state for approximately 5 minutes, then increase the inlet centrifugal pump input flow rate to 130% of the rated flow rate;

[0043] 16) Maintain this state for about 5 minutes. If there is no water leakage in the chamber, the mechanical seal is considered to be performing well.

[0044] 17) Close inlet valve 22 and outlet valve 6, and disconnect the motor power supply;

[0045] 18) Work completed.

Claims

1. A mechanical seal performance testing platform for pumps, characterized by: The machine seal to be tested is in transition fit with the shaft sleeve, the shell sleeve and the shell, and the shell sleeve is fastened through the machine seal gland and the bolt connection; the non-driving shaft is connected with the driving shaft through the shaft coupling, and is connected with the shaft sleeve and the shaft coupling through the key; the end cover is connected with the shell, the end cover is connected with the bearing frame, and the shell is connected with the base; the machine seal connects the machine seal gland and the end cover, so as to realize the positioning of the machine seal; the bearing is in interference fit with the non-driving shaft; the bearing gland is connected with the bearing frame, so as to fix the bearing; the motor side and the pump side of the shaft coupling are fixed through the key and the non-driving shaft, so as to realize the connection of the non-driving shaft and the driving shaft, the shaft coupling is provided with a shaft coupling protective cover, and the motor is connected with the base; the water inlet and outlet pipelines of the detection platform are horizontally radially input and vertically axially output, and are provided with an inlet valve, an outlet valve, an exhaust valve and an inlet pressure gauge and an outlet pressure gauge; the water supply of the inlet valve is the outlet water of the centrifugal pump, so that the input medium has certain kinetic energy and pressure energy, thereby simulating the real running condition of the centrifugal pump; The outlet valve is closed; the exhaust valve is opened; the inlet valve is opened; the inlet centrifugal pump is started to input medium, the flow is 50% of the rated flow of the centrifugal pump corresponding to the machine seal to be tested, so that the cooling water fills the chamber, thereby discharging the air in the chamber; after the chamber is exhausted, the motor is started, the rotating speed is 50% of the rated rotating speed of the centrifugal pump corresponding to the machine seal to be tested; the exhaust valve is closed; the outlet valve is gradually opened, the valve opening is slowly increased until fully opened after stable operation, and the outlet pressure gauge data is paid attention to at all times during operation; the rotating speed is kept at 50% for 5 minutes, the rotating speed of the motor is increased to 100%, the rotating speed is kept at 100% for 5 minutes, the rotating speed of the motor is increased to 130%, the rotating speed of the motor is adjusted to 100%, the input flow of the inlet centrifugal pump is increased to 100% of the rated flow, the state is kept for 5 minutes, the input flow of the inlet centrifugal pump is increased to 130% of the rated flow, the state is kept for 5 minutes, if there is no water leakage in the chamber, it is judged that the machine seal performance is good; the inlet valve and the outlet valve are closed, and the motor power supply is cut off; the work is finished.

2. The mechanical seal performance testing platform for pumps of claim 1, wherein: The non-driving shaft is a stepped shaft.

3. The mechanical seal performance testing platform for pumps of claim 1, wherein: The end cover and the shell are flange connected.

4. The mechanical seal performance testing platform for pumps of claim 1, wherein: The end cover is connected with the bearing frame through the bolt B.

5. The mechanical seal performance testing platform for pumps of claim 1, wherein: The shell is connected with the base through the bolt A.

6. The mechanical seal performance testing platform for pumps of claim 1, wherein: The machine seal is an integrated mechanical seal.

7. The mechanical seal performance testing platform for pumps of claim 1, wherein: The machine seal connects the machine seal gland and the end cover through the bolt A.

8. The mechanical seal performance testing platform for pumps of claim 1, wherein: The bearing gland is connected with the bearing frame through the bolt B.

9. The mechanical seal performance testing platform for pumps of claim 1, wherein: The motor is a variable frequency motor, and is connected with the base through the bolt A.

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