Method for measuring axial runout and wear of a turbo-assisted centrifugal pump

Abstract

The application discloses a novel steam-driven auxiliary centrifugal pump axial movement and wear measuring method, which comprises a steam-driven auxiliary feed water pump and a small steam turbine, the steam-driven auxiliary feed water pump is provided with the small steam turbine at the left side, the small steam turbine is connected with the central pipe in the middle of the steam-driven auxiliary feed water pump, the small steam turbine is connected with a cylinder head at the left side, the steam-driven auxiliary feed water pump and the small steam turbine are penetrated with a rotor shaft in the middle, and the rotor shaft is connected with a steam turbine disc at the left end. The novel steam-driven auxiliary centrifugal pump axial movement and wear measuring method can avoid the large workload of pump disassembly inspection and pump cover removal, save working time, improve the detection efficiency, and obtain the axial movement value of the pump rotor, the value can be accurately measured to 0.02mm according to the plug size, the accuracy is high, and more importantly, the method can obtain the wear amount of a certain direction on the two sides of the rotor balance piston, the abnormal position and direction of the equipment can be accurately positioned, and the equipment fault diagnosis is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of advanced maintenance methods and techniques, and in particular to a method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump. Background Art

[0002] At present, pressurized water reactor nuclear power plants are equipped with special safety facilities, among which the steam-driven auxiliary feedwater pump is a secondary nuclear safety equipment. When any main feedwater is lost in the nuclear island of the nuclear power plant, it supplies water to the secondary side of the steam generator, so its importance is self-evident; the steam-driven auxiliary feedwater pump is a bedroom multi-stage centrifugal pump driven by a small steam turbine. The small steam turbine impeller has a single row of blades. The pump impeller, guide vanes and small steam turbine impeller are all installed on the same shaft, which is supported by two water-lubricated radial bearings; the high-speed operation of the steam-driven pump is very likely to cause rotor wear, making the equipment unusable, so it is important to measure and inspect the axial movement and axial wear of the rotor.

[0003] 1. The pump cover on the water pump side needs to be removed, and a dial indicator is placed on the turbine side. Personnel push and pull the rotor to measure the movement. Disadvantages: Removing the pump cover and the turbine side cylinder cover in a nuclear power plant requires a lot of manpower and time, which takes more than one day. This causes the nuclear power plant's dedicated safety facilities to be unavailable for a long time, and the unit generates alarms. This is unsafe and unreliable. At the same time, this method can measure the total amount of movement, but it cannot clearly determine the amount of wear and the amount of wear in both directions of the rotor.

[0004] 2. Disassembly and direct measurement method. The water pump needs to be disassembled to measure the wear on both sides of the balance piston that limits the movement of the water pump rotor. The surface wear can be directly measured with a vernier caliper. The wear can be compared with the initial equipment parameters to determine the rotor movement and wear, and whether it exceeds the standard and needs replacement. This method can directly determine the wear amount, but the disadvantage is that it requires a complete disassembly of the water pump, consumes a large number of personnel, and occupies a long period of time when the nuclear power plant equipment is out of service, usually more than three days, resulting in significant economic losses and safety threats.

[0005] Therefore, a method for measuring the axial movement and wear of a pneumatic-assisted centrifugal pump is needed to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for measuring the axial movement and wear of a pneumatic-assisted centrifugal pump, so as to solve the problem proposed in the above background technology that the existing method for measuring the axial movement and wear of a centrifugal pump is complicated in detection process, consumes a lot of manpower and time, and requires a long detection time, which will cause great economic losses and safety threats.

[0007] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump, comprising a pneumatic-assisted feedwater pump and a small steam turbine:

[0008] A small steam turbine is provided on the left side of the steam-driven auxiliary water feed pump, and a central pipe is connected between the small steam turbine and the middle part of the steam-driven auxiliary water feed pump;

[0009] The left side of the small steam turbine is connected to a cylinder head, the pneumatic auxiliary feedwater pump and the middle of the small steam turbine are penetrated by a rotor shaft, and the left end of the rotor shaft is connected to a turbine disc;

[0010] The right end of the rotor shaft is connected to a balancing piston, a balancing disc is provided on the right side of the balancing piston, and a bearing seat is provided on the left side of the balancing piston;

[0011] A sleeve is provided on the left side of the cylinder head, and a fixing plate is fixedly connected to the right end of the sleeve;

[0012] An array of mounting holes is provided on the exterior of the fixing plate, and the fixing plate is fixedly connected to the cylinder head via bolts.

[0013] Preferably, the sleeve passes through a connecting rod, and a handle is connected to the left end of the connecting rod;

[0014] A connecting threaded screw is fixedly installed on the right end of the connecting rod, and the right end of the connecting threaded screw is threadedly connected to the turbine disc.

[0015] By adopting the above technical solution, the connection with the turbine disc is achieved through the connecting threaded screw installed at the right end of the connecting rod, so that the movement of the connecting rod can drive it and the rotor shaft to move synchronously.

[0016] Preferably, a limiting groove is provided at the left end of the connecting rod, and a threaded block is engaged and connected inside the limiting groove;

[0017] The right end of the handle passes through the threaded block, and the threaded block is connected to the handle bearing.

[0018] By adopting the above technical solution, the threaded block connected by the bearing can rotate outside the handle without moving axially.

[0019] Preferably, an inner wall of the left end of the sleeve is provided with an internal thread, and the threaded block is threadedly connected to the left end of the sleeve;

[0020] The left end of the threaded block is fixedly connected with a reference plate, and the reference plate is connected to the handle bearing, and the diameter of the reference plate is the same as the outer diameter of the sleeve.

[0021] By adopting the above technical solution, through the threaded connection between the threaded block and the sleeve, the threaded block can be rotated during measurement, thereby driving the axial movement of the rotor shaft through the connecting rod, and the position between the reference plate and the sleeve can be fixed, making it easier to measure the distance between them.

[0022] Preferably, the centrifugal pump axial movement and wear measurement method specifically includes the following steps:

[0023] S1: Installation of casing and connecting rod;

[0024] S2: Measure the axial movement and wear of the equipment when it is not in operation;

[0025] S3: Measure the axial movement and wear of the equipment after operation;

[0026] S4: Calculate the wear and total movement of the equipment and determine whether it meets the standards.

[0027] Preferably, the specific steps of S1 are:

[0028] Remove the steam side center pipe of the steam-driven auxiliary water feed pump, and fix the fixing plate and sleeve to the left cylinder head of the steam-driven auxiliary water feed pump by passing bolts through the mounting holes; then install the connecting rod inside the sleeve, and thread the connecting threaded screw and threaded block to the turbine disc and the left end of the sleeve respectively.

[0029] Preferably, the specific steps of S2 are:

[0030] Rotate the threaded block clockwise to push the rotor shaft toward the water pump side through the connecting rod. At this time, the balancing piston and the balancing plate are in contact. Use a vernier caliper to measure the gap between the left end face of the casing and the reference plate to obtain the initial value A1 when the equipment is not in operation and the rotor shaft is not worn.

[0031] Rotate the threaded block counterclockwise to pull the rotor shaft toward the cylinder head side through the connecting rod. At this time, the balance piston fits against the bearing seat. Use a vernier caliper to measure the gap between the left end face of the sleeve and the reference plate to obtain the initial value A2 when the equipment is not in operation and the rotor shaft is not worn. Then, when the equipment is not in operation and the rotor shaft is not worn, the rotor shaft movement value of the pneumatic auxiliary water supply pump is A1-A2=A3. At this time, the wear between the dynamic and static parts and the balance piston is 0.

[0032] Preferably, the specific steps of S3 are:

[0033] The S2 method is used to further analyze the rotor shaft movement and the wear of the balance piston after the equipment is in operation. By measuring the values ​​of B1 and B2 when the rotor shaft is in a worn state after the equipment is in operation, it is concluded that the total movement value of the rotor shaft of the pneumatic auxiliary water supply pump when the rotor shaft is in a worn state after the equipment is in operation is B1-B2=B3.

[0034] Preferably, the specific steps of S4 are:

[0035] The change in the axial movement of the rotor shaft and the wear of the balancing piston are calculated using the values ​​measured on both sides;

[0036] The axial movement value of the rotor shaft of the pneumatic auxiliary water supply pump is C3=B3-A3;

[0037] The rotor is pushed toward the water pump side, and the balance piston and balance disc come into contact and wear occurs. The wear amount can be calculated as X=B1-A1;

[0038] The rotor is pushed toward the cylinder head side, and the balance piston contacts the end face of the bearing seat and wears. The wear amount can be calculated as Y=B2-A2;

[0039] By calculating the measured values, if the axial runout of the rotor shaft exceeds the standard value specified by the nuclear power plant, it means that the equipment has abnormal wear and needs to be inspected and processed; similarly, when the X and Y values ​​of the wear on both sides of the balancing piston exceed the standard values ​​specified by the nuclear power plant, the direction of wear of the balancing piston should be determined first, and then targeted inspections and component replacements should be carried out.

[0040] Compared with the prior art, the present invention has the following beneficial effects: the method for measuring the axial play and wear of a pneumatic-assisted centrifugal pump can avoid the large workload of disassembling the water pump for inspection and removing the pump cover, saving working time and improving detection efficiency. At the same time, the axial play value of the water pump rotor can be obtained, and the value can be accurately measured to 0.02 mm based on the plug gauge, with high accuracy. More importantly, this method can obtain the wear amount in a certain direction on both sides of the rotor balancing piston, which can accurately locate the abnormal position and direction of the equipment and facilitate equipment fault diagnosis and fault mode.

[0041] 1. This method only requires the removal of the cylinder head and the quick installation of the detection equipment to conduct the test, saving manpower and solving the problem of the long time required to dismantle the water pump or remove the pump cover, which poses a great safety hazard.

[0042] 2. This detection method has higher numerical detection accuracy for the axial movement of centrifugal pumps. At the same time, it can calculate the specific wear direction of the balance piston based on the numerical value, which is convenient for judging and accurately locating the abnormal parts and directions of the equipment, and facilitating fault diagnosis and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a schematic diagram of the front cross-sectional structure of the present invention;

[0044] Figure 2 This is a schematic diagram of the structure of the fixing plate and the cylinder head of the present invention;

[0045] Figure 3 This is a schematic diagram of the connecting rod and handle structure of the present invention;

[0046] Figure 4 This is a schematic diagram of the structure of the sleeve and the fixed disk of the present invention;

[0047] Figure 5 This is a schematic cross-sectional view of the measuring tool of the present invention;

[0048] Figure 6This is a schematic diagram of the three-dimensional structure of the measuring tool of the present invention;

[0049] Figure 7 It is a structural schematic diagram of the threaded block and the reference plate of the present invention.

[0050] In the figure: 1. Pneumatic auxiliary water pump; 2. Small steam turbine; 3. Center pipe; 4. Cylinder head; 5. Rotor shaft; 6. Turbine disc; 7. Balance piston; 8. Balance disc; 9. Bearing seat; 10. Sleeve; 11. Fixed disc; 12. Mounting hole; 13. Connecting rod; 14. Handle; 15. Connecting threaded screw; 16. Limiting groove; 17. Threaded block; 18. Reference plate. DETAILED DESCRIPTION

[0051] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0052] See also Figure 1-7 , the present invention provides a technical solution:

[0053] A method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump includes a pneumatic-assisted feedwater pump 1 and a small steam turbine 2. The small steam turbine 2 is provided on the left side of the pneumatic-assisted feedwater pump 1, and a center pipe 3 is connected to the middle of the small steam turbine 2 and the pneumatic-assisted feedwater pump 1; a cylinder head 4 is connected to the left side of the small steam turbine 2, a rotor shaft 5 passes through the middle of the pneumatic-assisted feedwater pump 1 and the small steam turbine 2, and a turbine disk 6 is connected to the left end of the rotor shaft 5; a balancing piston 7 is connected to the right end of the rotor shaft 5, and a balancing disk 8 is provided on the right side of the balancing piston 7, and a bearing seat 9 is provided on the left side of the balancing piston 7; a sleeve 10 is provided on the left side of the cylinder head 4, and a fixed disk 11 is fixedly connected to the right end of the sleeve 10; an array of mounting holes 12 are opened on the outer surface of the fixed disk 11, and the fixed disk 11 is fixedly connected to the cylinder head 4 by bolts. The small steam turbine 2 serves as a power drive, and drives the pump impeller inside the pneumatic-assisted feedwater pump 1 to rotate through the rotor shaft 5 to work.

[0054] The inside of the sleeve 10 passes through the connecting rod 13, and the left end of the connecting rod 13 is connected to the handle 14, the right end of the connecting rod 13 is fixedly installed with a connecting threaded screw 15, and the right end of the connecting threaded screw 15 is threadedly connected to the turbine disc 6; the left end of the connecting rod 13 is provided with a limiting groove 16, and the limiting groove 16 is internally engaged with a threaded block 17, the right end of the handle 14 passes through the threaded block 17, and the threaded block 17 is connected to the bearing of the handle 14; the inner wall of the left end of the sleeve 10 is provided with an internal thread, and the threaded block 17 is threadedly connected to the left end of the sleeve 10, the left end of the threaded block 17 is fixedly connected with a reference plate 18, and the reference plate 18 is connected to the bearing of the handle 14, and the diameter of the reference plate 18 is the same as the outer diameter of the sleeve 10; when measuring in use, the pneumatic auxiliary The steam side center pipe 3 of the feed water pump 1 is removed, and the fixed plate 11 at the right end of the sleeve 10 is fixed to the cylinder head 4 by bolts. The connecting rod 13 is passed through the inside of the sleeve 10, and the connecting threaded screw 15 installed on the right end of the connecting rod 13 is connected to the turbine disk 6. At the same time, the threaded block 17 is threadedly connected to the left end of the sleeve 10. The position of the connecting rod 13 and the turbine disk 6 can be adjusted by rotating the threaded block 17, and the rotor shaft 5 and the balance piston 7 are synchronously driven to move through the turbine disk 6. The rotor shaft 5 is driven to move in different axial directions by rotating the threaded block 17 in both directions. The axial movement value of the rotor shaft 5 and the wear amount of the balance piston 7 are obtained by measuring the distance between the reference plate 18 and the sleeve 10.

[0055] The method for measuring the axial movement and wear of a centrifugal pump includes the following steps:

[0056] S1: Installation of the sleeve 10 and the connecting rod 13; remove the steam side center pipe 6 of the steam-driven auxiliary water supply pump 1, and fix the fixing plate 11 and the sleeve 10 to the left cylinder head 4 of the steam-driven auxiliary water supply pump 1 by passing the bolts through the mounting hole 12; then install the connecting rod 13 inside the sleeve 10, and thread the connecting threaded screw 15 and the threaded block 17 to the turbine disc 6 and the left end of the sleeve 10 respectively.

[0057] S2: Measure the axial movement and wear of the equipment when not in operation. Rotate the threaded block 17 clockwise via the connecting rod 13 to push the rotor shaft 5 toward the water pump. The balancing piston 7 and balancing disc 8 are now in contact. Use a vernier caliper to measure the gap between the left end face of the casing 10 and the reference plate 18. This yields the initial value A1 of the rotor shaft 5 when the equipment is not in operation and unworn.

[0058] Rotate the threaded block 17 counterclockwise to pull the rotor shaft 5 toward the cylinder head 4 side through the connecting rod 13. At this time, the balancing piston 7 is in contact with the bearing seat 9. The gap between the left end face of the sleeve 10 and the reference plate 18 is measured with a vernier caliper to obtain the initial value A2 of the rotor shaft 5 when the equipment is not in operation and is not worn. Then, the movement value of the rotor shaft 5 of the pneumatic auxiliary water supply pump 1 when the equipment is not in operation and is not worn is A1-A2=A3. At this time, the wear between the dynamic and static parts and the balancing piston 7 is 0.

[0059] S3: Measure the axial movement and wear of the equipment after operation; use the method of S2 to measure the movement of the rotor shaft 5 and the wear of the balance piston 7 after the equipment is in operation. By measuring the values ​​of the rotor shaft 5 in the wear state after the equipment is in operation as B1 and B2, it is concluded that the total movement value of the rotor shaft 5 of the pneumatic auxiliary water supply pump 1 in the wear state after the equipment is in operation is B1-B2=B3.

[0060] S4: Calculate the wear and total movement of the equipment and determine whether they meet the standards; calculate the change in axial movement of the rotor shaft 5 and the wear of the balancing piston 7 based on the values ​​measured on both sides;

[0061] a. The axial movement value of the rotor shaft 5 of the steam-driven auxiliary water pump 1 is C3=B3-A3;

[0062] b. The rotor is pushed toward the water pump side, and the balancing piston 7 and the balancing disc 8 come into contact and wear occurs. The wear amount can be calculated as X=B1-A1;

[0063] c. The rotor is pushed toward the cylinder head, and the balance piston 7 and the end surface of the bearing seat 9 come into contact and wear occurs. The wear amount can be calculated as Y=B2-A2;

[0064] d. By calculating the measured values, if the axial runout of the rotor shaft 5 exceeds the standard value specified by the nuclear power plant, it indicates that the equipment has experienced abnormal wear and requires inspection and treatment. Similarly, if the X and Y values ​​of the wear on both sides of the balance piston 7 exceed the standard values ​​specified by the nuclear power plant, first determine the direction of wear of the balance piston 7, and then conduct targeted inspection and replacement of components.

[0065] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for measuring axial movement and wear of a steam-assisted centrifugal pump, comprising a steam-assisted feedwater pump (1) and a small steam turbine (2), characterized in that: A small steam turbine (2) is provided on the left side of the steam-driven auxiliary water feed pump (1), and a central pipe (3) is connected between the small steam turbine (2) and the middle of the steam-driven auxiliary water feed pump (1); The left side of the small steam turbine (2) is connected to a cylinder head (4), the middle of the steam-driven auxiliary water supply pump (1) and the small steam turbine (2) is penetrated by a rotor shaft (5), and the left end of the rotor shaft (5) is connected to a turbine disc (6); The right end of the rotor shaft (5) is connected to a balancing piston (7), a balancing disc (8) is provided on the right side of the balancing piston (7), and a bearing seat (9) is provided on the left side of the balancing piston (7); A sleeve (10) is provided on the left side of the cylinder head (4), and a fixing plate (11) is fixedly connected to the right end of the sleeve (10), a connecting rod (13) passes through the interior of the sleeve (10), and a handle (14) is connected to the left end of the connecting rod (13), the right end of the handle (14) passes through the threaded block (17), and the left end of the threaded block (17) is fixedly connected to a reference plate (18); An array of mounting holes (12) is provided on the exterior of the fixing plate (11), and the fixing plate (11) is fixedly connected to the cylinder head (4) via bolts; The centrifugal pump axial movement and wear measurement method specifically includes the following steps: S1: Installation of the sleeve (10) and the connecting rod (13); S2: Measure the axial movement and wear of the equipment when it is not in operation; The specific steps of S2 are: rotating the threaded block (17) clockwise to push the rotor shaft (5) toward the water pump side through the connecting rod (13), at which time the balancing piston (7) and the balancing disc (8) are in contact, and the gap between the left end face of the sleeve (10) and the reference plate (18) is measured with a vernier caliper to obtain the initial value A1 of the rotor shaft (5) in the non-operating state without wear; The threaded block (17) is rotated counterclockwise to pull the rotor shaft (5) toward the cylinder head (4) through the connecting rod (13). At this time, the balancing piston (7) is fitted with the bearing seat (9). The gap between the left end face of the sleeve (10) and the reference plate (18) is measured with a vernier caliper to obtain the initial value A2 of the rotor shaft (5) in the non-operating state and the non-worn state of the equipment. The play value of the rotor shaft (5) of the pneumatic auxiliary water supply pump (1) in the non-operating state and the non-worn state of the rotor shaft (5) is A1-A2=A3. At this time, the wear between the dynamic and static parts and the balancing piston (7) is 0. S3: Measure the axial movement and wear of the equipment after operation; The specific steps of S3 are: using the method of S2 to further measure the movement of the rotor shaft (5) and the wear of the balance piston (7) after the equipment is in operation, and by measuring the values ​​of the rotor shaft (5) in the wear state after the equipment is in operation as B1 and B2, it is obtained that the total movement value of the rotor shaft (5) of the pneumatic auxiliary water supply pump (1) in the wear state after the equipment is in operation is B1-B2=B3; S4: Calculate the wear and total movement value of the equipment and determine whether it meets the standards; The specific steps of S4 are: calculating the change of the axial movement of the rotor shaft (5) and the wear amount of the balance piston (7) through the values ​​measured on both sides; The axial play of the rotor shaft (5) of the steam-driven auxiliary water pump (1) is C3=B3-A3; The rotor is pushed toward the water pump side, and the balancing piston (7) and the balancing disc (8) come into contact and wear occurs. The wear amount can be obtained as X=B1-A1; The rotor is pushed toward the cylinder head side, and the balance piston (7) and the end face of the bearing seat (9) come into contact and wear occurs. The wear amount can be obtained as Y=B2-A2.

2. A method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump according to claim 1, characterized in that: A connecting threaded screw (15) is fixedly mounted on the right end of the connecting rod (13), and the right end of the connecting threaded screw (15) is threadedly connected to the turbine disc (6).

3. A method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump according to claim 2, characterized in that: A limiting groove (16) is provided at the left end of the connecting rod (13), and a threaded block (17) is engaged and connected inside the limiting groove (16); The threaded block (17) is connected to the handle (14) bearing.

4. A method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump according to claim 3, characterized in that: An inner wall of the left end of the sleeve (10) is provided with an internal thread, and the threaded block (17) is threadedly connected to the left end of the sleeve (10); The reference plate (18) is connected to the handle (14) bearing, and the diameter of the reference plate (18) is the same as the outer diameter of the sleeve (10).

5. The method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump according to claim 2, characterized in that: The specific steps of S1 are: The steam-side center pipe (3) of the steam-driven auxiliary water-feeding pump (1) is removed, and the fixing plate (11) and the sleeve (10) are fixed to the left cylinder head (4) of the steam-driven auxiliary water-feeding pump (1) by passing the bolts through the mounting holes (12); the connecting rod (13) is then installed inside the sleeve (10), and the connecting threaded screw (15) and the threaded block (17) are respectively threadedly connected to the turbine disc (6) and the left end of the sleeve (10).

6. The method for measuring axial movement and wear of a pneumatic-assisted centrifugal pump according to claim 1, characterized in that: The specific steps of S4 are: By calculating the measured values, if the axial play of the rotor shaft (5) exceeds the standard value specified by the nuclear power plant, it indicates that the equipment has experienced abnormal wear and needs to be inspected and processed; similarly, when the wear X and Y values ​​on both sides of the balancing piston (7) exceed the standard value specified by the nuclear power plant, the wear direction of the balancing piston (7) is first determined, and then targeted inspection and component replacement are carried out.

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