A large axial flow propeller unit thrust bearing modification structure and elevation determination method

Abstract

The application discloses a large-scale axial flow variable-pitch unit thrust bearing reforming structure and an elevation determining method, which comprises a thrust bearing seat, wherein the thrust bearing seat is fixedly installed at the top end of a thrust support; the top end of the thrust bearing seat is supported by a spring bundle with a bearing pad, the top end of the bearing pad is supported by a thrust pad, and the top end of the thrust pad is supported by a mirror plate. The original elastic oil tank of the thrust bearing structure of a large or medium-sized axial flow variable-pitch water turbine generator is reformed into a spring bundle structure, and the spring bundle structure can meet the performance requirements. Moreover, after the reform, the elevation determining method is used to ensure that the bearing elevations before and after the reform are within the design requirements, and the elevation deviation accuracy requirements are met.

Description

Technical Field

[0001] This invention relates to the field of hydropower equipment retrofitting technology, and in particular to a retrofitting structure and elevation determination method for the thrust bearing of a large axial-flow propeller turbine unit. Background Technology

[0002] A hydroelectric power station with an axial-flow propeller turbine unit has been in operation for nearly 40 years. The equipment and units are severely aging and their performance has deteriorated. (See below) Figure 1 In particular, the original thrust bearing support type of the unit was a flexible oil tank 17, which cannot meet the usage requirements. Therefore, the unit equipment needs to be upgraded and replaced.

[0003] Furthermore, the thrust bearing elevation determines the elevation of the rotating parts of the unit. To ensure that the elevation of the rotating parts before and after the unit modification is consistent with that before the modification, it is necessary to precisely control the elevation deviation of the upper surface of the thrust bearing under load to within 0.50mm, a very strict standard. However, after modifying the existing elastic oil tank structure, the thrust bearing elevation changed accordingly. Therefore, it is necessary to readjust and determine the thrust bearing elevation to meet performance requirements. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a modified structure and elevation determination method for the thrust bearing of a large axial-flow propeller turbine unit. This involves modifying the elastic oil tank of the original large and medium-sized axial-flow propeller turbine generator thrust bearing structure into a spring bundle structure, ensuring that it meets performance requirements. Furthermore, after the modification, the elevation determination method ensures that the bearing elevation before and after the modification is within the design requirements, satisfying the elevation deviation accuracy requirements.

[0005] To achieve the above-mentioned technical effects, the present invention aims to provide a modified thrust bearing structure for a large axial-flow propeller turbine unit, comprising a thrust bearing housing, wherein the thrust bearing housing is fixedly installed at the top of a thrust support; a bearing pad is supported at the top of the thrust bearing housing by a spring bundle, a thrust bearing is supported at the top of the bearing pad, and a mirror plate is supported at the top of the thrust bearing.

[0006] The thrust bearing housing includes a flange base and a top support base. The flange base and the flange face at the top of the thrust bracket form a flange connection. The top support base is located at the top of the thrust bearing housing.

[0007] A first elevation limiting structure is provided between the top support and the thrust bearing. The first elevation limiting structure includes a first hook plate fixed to the outer wall of the top support by a first bolt. The top hook of the first hook plate engages with a first limiting groove provided on the outer wall of the thrust bearing.

[0008] A second elevation limiting structure is provided between the top support and the tile. The second elevation limiting structure includes a second hook plate fixed to the outer wall of the top support by a second bolt. The top hook of the second hook plate cooperates with the second limiting groove provided on the outer wall of the tile.

[0009] The outer walls of the support plate and the thrust plate are fixedly connected by a connecting assembly, which consists of a connecting plate fixed between the support plate and the thrust plate by a third bolt.

[0010] A method for determining the elevation of a thrust bearing retrofit structure for a large axial-flow propeller turbine unit: During the modification process, the thrust support is not replaced, but the upper flange surface of the thrust support needs to be processed. Among them, the modified spring bundle, bearing pad and thrust pad are standard parts, and their height cannot be adjusted. The thrust bearing elevation can only be adjusted by processing the thrust bearing seat or adding a shim to the lower surface of the thrust bearing seat. The adjustment objective is to ensure that the elevation of the upper surface of the mirror plate is consistent under stress before and after the modification. Given that the height of the spring bundle is E, the combined height of the thrust pad and the support pad is F, the compression of the spring bundle under force is ξ, and the machining allowance of the upper flange surface of the thrust bracket is δ; The elevation determination method specifically includes the following steps: Step 1, Pre-repair measurements; Step 2, Determining the machining height H of the thrust bearing housing in the factory; Step 3, Measurements before pre-assembly of the thrust bearing; Step 4: Measurement after the thrust bearing is officially installed.

[0011] The specific steps of step 1 are as follows: Step 1.1 After the pre-repair rotation is qualified, use a height gauge to measure the height A1 from the upper surface of the mirror plate to the bottom of the thrust oil groove. Measure 4 points evenly distributed in the circumferential direction, and take the average value of the 4 points for the height difference A1. Step 1.2: After the pre-repair rotation is qualified, set up a dial indicator at each elastic oil tank and measure the force value B of the elastic oil tank before and after the rotor is lifted. The force value B is the average value of the force values ​​of all elastic oil tanks. Step 1.3: After the rotor is lifted out, measure the elevation C1 of the upper surface of the mirror plate relative to the elevation benchmark point on the foundation. Measure 8 points evenly distributed in the circumferential direction, and take the average value of the 8 points for elevation C1. Step 1.4: After the rotor is lifted out, measure the elevation D1 of the bottom of the thrust oil tank relative to the elevation benchmark point on the foundation. Measure 8 points evenly distributed in the circumferential direction, and take the average value of the 8 points for elevation D1.

[0012] The specific steps of step 2 are as follows: Based on the principle that the elevation of the upper surface of the mirror plate is consistent under the stress state before and after repair, and the height of the upper surface of the mirror plate from the bottom of the thrust oil groove under the stress state after repair is A1, the formula for calculating the machining height H of the thrust bearing housing in the factory is: H = A1 + δ + ξ - EF (1) In the formula: H is the height of the thrust bearing seat; A1 is the height from the upper surface of the mirror plate to the bottom of the thrust oil groove; δ is the machining amount of the upper flange surface of the thrust bracket; ξ is the compression amount of the spring bundle after being stressed; E is the height of the spring bundle; F is the combined height of the thrust pad and the support pad.

[0013] The specific steps of step 3 are as follows: Step 3.1: After the thrust bracket and thrust bearing housing are processed, they are assembled in the factory. The assembled thrust bracket is hoisted into the machine pit for pre-installation. After pre-installation, the elevation D2 of the bottom of the thrust oil tank relative to the elevation benchmark point on the foundation is measured. Eight points are measured in the circumferential direction, and the average value of the eight points is taken as the elevation D2. Step 3.2: Hoist the mirror plate and place it above the thrust pad. Measure the elevation C2 of the upper surface of the mirror plate relative to the elevation benchmark point on the foundation. Measure 8 points evenly distributed in the circumferential direction and take the average value of the 8 points for elevation C2. Step 3.3: Before repair, the elevation of the upper surface of the mirror plate under stress should be the difference between the elevation C1 of the unstressed upper surface of the mirror plate and the stress value B of the elastic oil tank, C1-B. After repair, the elevation of the upper surface of the mirror plate under stress should be C2-ξ. The deviation between the two is G=C1-B-(C2-ξ). If -0.50mm≤G≤0.50mm, the elevation meets the requirements. If G<-0.50mm, the elevation of the repaired mirror plate is too high, and the thrust bearing seat needs to be machined. The machining amount is G. If G>0.50mm, the elevation of the repaired mirror plate is too low, and a shim needs to be added to the lower part of the thrust bearing seat. The thickness of the shim is G.

[0014] The specific steps of step 4 are as follows: After the unit is turned around, measure the height A2 from the upper surface of the mirror plate to the bottom of the thrust oil groove under the stress state. Measure 4 points evenly distributed in the circumferential direction. Take the average value of the 4 points for the height difference A2. Compare the deviation between A1 and A2. The deviation should be within 0.50mm. Otherwise, make adjustments.

[0015] The present invention has the following beneficial effects: 1. This method uses a dimensional chain to calculate the machining height of the thrust bearing housing. The dimensional chain forms a closed loop, making the calculation method reliable and highly operable. It has been put into practice in the renovation of a power plant unit and is entirely feasible.

[0016] 2. This method takes into account the differences in the processing amount of the thrust support, the force value of the elastic oil tank and the force value of the small spring, and can ensure the consistency of the elevation before and after the modification.

[0017] 3. This method verifies the elevation of the thrust bearing during the pre-assembly process and moves the control point forward, which can detect elevation deviation problems in advance, handle them in advance, and reduce the major risk of elevation deviation. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is a structural diagram before the modification.

[0020] Figure 2 This is a structural diagram of the modified version of the present invention.

[0021] Figure 3 This is a diagram of the measurement process in step 2 of the present invention.

[0022] Figure 4 This is a diagram of the measurement process in step 3 of the present invention.

[0023] In the diagram: 1. Thrust bracket; 2. Flange base; 3. Thrust bearing seat; 4. Top support seat; 5. Spring bundle; 6. First bolt; 7. First hook plate; 8. First limiting groove; 9. Support plate; 10. Thrust pad; 11. Mirror plate; 12. Connecting plate; 13. Third bolt; 14. Second limiting groove; 15. Second hook plate; 16. Second bolt; 17. Elastic oil tank; 18. Foundation. Detailed Implementation

[0024] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0025] Example 1: See Figure 1-4 A modified thrust bearing structure for a large axial-flow propeller turbine generator unit includes a thrust bearing housing 3, which is fixedly installed at the top of a thrust support 1. A bearing pad 9 is supported at the top of the thrust bearing housing 3 by a spring bundle 5, a thrust bearing pad 10 is supported at the top of the bearing pad 9, and a mirror plate 11 is supported at the top of the thrust bearing pad 10. By modifying the elastic oil tank of the original large and medium-sized axial-flow propeller turbine generator thrust bearing structure to a spring bundle structure, and ensuring that it meets performance requirements, the modification is further enhanced by using an elevation determination method to ensure that the bearing elevation before and after the modification is within the design requirements, thus meeting the elevation deviation accuracy requirements.

[0026] Furthermore, the thrust bearing housing 3 includes a flange base 2 and a top support 4. The flange base 2 and the flange face at the top of the thrust bracket 1 form a flange connection; the top support 4 is located at the top of the thrust bearing housing 3. The thrust bearing housing 3 is manufactured using a factory-customized method, allowing its height to be customized to meet subsequent elevation adjustments.

[0027] Furthermore, a first elevation limiting structure is provided between the top support 4 and the thrust bearing 10. The first elevation limiting structure includes a first hook plate 7 fixed to the outer wall of the top support 4 by a first bolt 6. The top hook of the first hook plate 7 engages with a first limiting groove 8 provided on the outer wall of the thrust bearing 10. The aforementioned first elevation limiting structure provides a certain limiting effect.

[0028] Furthermore, a second elevation limiting structure is provided between the top support 4 and the tile 9. The second elevation limiting structure includes a second hook plate 15 fixed to the outer wall of the top support 4 by a second bolt 16. The top hook of the second hook plate 15 engages with a second limiting groove 14 provided on the outer wall of the tile 9. The aforementioned second elevation limiting structure provides a certain limiting effect.

[0029] Furthermore, the outer walls of the bearing 9 and the thrust bearing 10 are fixedly connected by a connecting assembly, which is composed of a connecting plate 12 fixed between the bearing 9 and the thrust bearing 10 by a third bolt 13. The connecting assembly allows the bearing 9 and the thrust bearing 10 to be connected as a whole.

[0030] Example 2: A method for determining the elevation of a thrust bearing retrofit structure for a large axial-flow propeller turbine unit: During the modification process, the thrust bracket 1 is not replaced, but the upper flange surface of the thrust bracket 1 needs to be processed. Among them, the modified spring bundle 5, bearing pad 9 and thrust pad 10 are standard parts, and their height cannot be adjusted. The thrust bearing elevation can only be adjusted by processing the thrust bearing seat 3 or adding a shim to the lower surface of the thrust bearing seat 3. The adjustment objective is to ensure that the elevation of the upper surface of the mirror plate 11 is consistent under stress before and after the modification. It is known that the height of spring bundle 5 is E, the combined height of thrust pad 10 and support pad 9 is F, the compression of spring bundle 5 after being subjected to force is ξ, and the machining amount of the upper flange surface of thrust bracket 1 is δ. The elevation determination method specifically includes the following steps: Step 1, Pre-repair measurements; Step 2, Determining the in-factory machining height H of the thrust bearing housing 3; Step 3, Measurements before pre-assembly of the thrust bearing; Step 4: Measurement after the thrust bearing is officially installed.

[0031] The specific steps of step 1 are as follows: Step 1.1 After the pre-repair rotation is qualified, use a height gauge to measure the height A1 from the upper surface of the mirror plate 11 to the bottom of the thrust oil groove. Measure 4 points evenly distributed in the circumferential direction, and take the average value of the 4 points for the height difference A1. Step 1.2: After the pre-repair rotation is qualified, set up a dial indicator at each elastic oil tank 17 and measure the force value B of the elastic oil tank 17 before and after the rotor is lifted. The force value B is the average value of the force values ​​of all elastic oil tanks 17. Step 1.3: After the rotor is lifted out, measure the elevation C1 of the upper surface of the mirror plate 11 relative to the elevation reference point on the foundation 18. Measure 8 points evenly distributed in the circumferential direction, and take the average value of the 8 points for elevation C1. Step 1.4: After the rotor is lifted out, measure the elevation D1 of the bottom of the thrust oil tank relative to the elevation reference point on the foundation 18. Measure 8 points evenly distributed in the circumferential direction, and take the average value of the 8 points for elevation D1.

[0032] The specific steps of step 2 are as follows: Based on the principle that the elevation of the upper surface of the mirror plate 11 is consistent under the stress state before and after repair, and the height of the upper surface of the mirror plate 11 from the bottom of the thrust oil groove under the stress state after repair is A1, the formula for calculating the in-factory machining height H of the thrust bearing seat 3 is: H=A1+δ+ξ-E-F1 In the formula: H is the height of the thrust bearing seat 3, A1 is the height from the upper surface of the mirror plate 11 to the bottom of the thrust oil groove; δ is the machining amount of the upper flange surface of the thrust bracket 1; ξ is the compression amount of the spring bundle 5 after being subjected to force; E is the height of the spring bundle 5; F is the combined height of the thrust pad 10 and the support pad 9.

[0033] The specific steps of step 3 are as follows: Step 3.1 After the thrust bracket 1 and thrust bearing housing 3 are processed, they are assembled in the factory. The assembled thrust bracket 1 is hoisted into the machine pit for pre-installation. After pre-installation, the elevation D2 of the bottom of the thrust oil tank relative to the elevation reference point on the foundation 18 is measured. Eight points are measured in the circumferential direction, and the average value of the eight points is taken as the elevation D2. Step 3.2: Hoist the mirror plate 11 and place it above the thrust bearing 10. Measure the elevation C2 of the upper surface of the mirror plate 11 relative to the elevation reference point on the foundation 18. Measure 8 points evenly distributed in the circumferential direction and take the average value of the 8 points for elevation C2. Step 3.3: Before repair, the elevation of the upper surface of the mirror plate 11 after being subjected to force should be the difference between the elevation value C1 of the upper surface of the unloaded mirror plate and the force value B of the elastic oil tank 17, C1-B. After repair, the elevation value of the upper surface of the mirror plate after being subjected to force should be C2-ξ. The deviation between the two is G=C1-B-(C2-ξ). If -0.50mm≤G≤0.50mm, the elevation meets the requirements. If G<-0.50mm, the elevation value of the repaired mirror plate is too high, and the thrust bearing seat needs to be machined. The machining amount is G. If G>0.50mm, the elevation value of the repaired mirror plate is too low, and a shim needs to be added to the lower part of the thrust bearing seat. The thickness of the shim is G.

[0034] The specific steps of step 4 are as follows: After the unit is turned around, measure the height A2 from the upper surface of the mirror plate to the bottom of the thrust oil groove under the stress state. Measure 4 points evenly distributed in the circumferential direction. Take the average value of the 4 points for the height difference A2. Compare the deviation between A1 and A2. The deviation should be within 0.50mm. Otherwise, make adjustments.

Claims

1. A method for determining the elevation of a thrust bearing modification structure for a large axial-flow propeller turbine unit, wherein the thrust bearing modification structure for the large axial-flow propeller turbine unit includes a thrust bearing housing (3), the thrust bearing housing (3) being fixedly installed at the top of a thrust support (1); the top of the thrust bearing housing (3) is supported by a bearing pad (9) via a spring bundle (5), the top of the bearing pad (9) is supported by a thrust pad (10), and the top of the thrust pad (10) is supported by a mirror plate (11). characterized in that The method includes: During the modification process, the thrust bracket (1) is not replaced. The upper flange surface of the thrust bracket (1) needs to be processed. The modified spring bundle (5), bearing pad (9) and thrust pad (10) are standard parts with unadjustable height. The thrust bearing elevation can only be adjusted by processing the thrust bearing seat (3) or by adding pads to the lower surface of the thrust bearing seat (3). The adjustment objective is to ensure that the elevation of the upper surface of the mirror plate (11) is consistent under stress before and after the modification. It is known that the height of the spring bundle (5) is E, the combined height of the thrust pad (10) and the support pad (9) is F, the compression of the spring bundle (5) after being subjected to force is ξ, and the machining amount of the upper flange surface of the thrust bracket (1) is δ. The elevation determination method specifically includes the following steps: Step 1, Pre-repair measurements; Step 1.1 After the pre-repair turning is qualified, use a height gauge to measure the height A1 from the upper surface of the mirror plate (11) to the bottom of the thrust oil groove. Measure 4 points evenly distributed in the circumferential direction, and take the average value of the 4 points for the height difference A1. Step 1.2 After the pre-repair rotation is qualified, set up a dial indicator at each elastic oil tank (17) and measure the force value B of the elastic oil tank (17) before and after the rotor is lifted. The force value B is the average value of the force values ​​of all elastic oil tanks (17). Step 1.3 After the rotor is lifted out, measure the elevation C1 of the upper surface of the mirror plate (11) relative to the elevation reference point on the foundation (18). Measure 8 points evenly distributed in the circumferential direction, and take the average value of the 8 points for elevation C1. Step 1.4 After the rotor is lifted out, measure the elevation D1 of the bottom of the thrust oil tank relative to the elevation reference point on the foundation (18). Measure 8 points evenly distributed in the circumferential direction, and take the average value of the 8 points for elevation D1. Step 2, Determining the in-factory machining height H of the thrust bearing housing (3); Based on the principle that the elevation of the upper surface of the mirror plate (11) is consistent under the stress state before and after repair, and the height of the upper surface of the mirror plate (11) from the bottom of the thrust oil groove under the stress state after repair is A1, then the formula for calculating the in-plant machining height H of the thrust bearing seat (3) is: H = A1 + δ + ξ - EF (1) In the formula: H is the height of the thrust bearing seat (3), A1 is the height from the upper surface of the mirror plate (11) to the bottom of the thrust oil groove; δ is the machining amount of the upper flange surface of the thrust bracket (1); ξ is the compression amount of the spring bundle (5) after being subjected to force; E is the height of the spring bundle (5); F is the combined height of the thrust pad (10) and the support pad (9); Step 3, Measurements before pre-assembly of the thrust bearing; Step 3.1 After the thrust bracket (1) and thrust bearing seat (3) are processed, they are assembled in the factory. The assembled thrust bracket (1) is hoisted into the machine pit for pre-installation. After the pre-installation is completed, the elevation D2 of the bottom of the thrust oil tank relative to the elevation reference point on the foundation (18) is measured. Eight points are measured in the circumferential direction, and the average value of the eight points is taken as the elevation D2. Step 3.2, hoist the mirror plate (11) and place it above the thrust bearing (10). Measure the elevation C2 of the upper surface of the mirror plate (11) relative to the elevation benchmark point on the foundation (18). Measure 8 points evenly distributed in the circumferential direction and take the average value of the 8 points for elevation C2. Step 3.3: Before repair, the elevation of the upper surface of the mirror plate (11) after being subjected to force should be the difference between the elevation value C1 of the upper surface of the unforced mirror plate and the force value B of the elastic oil tank (17), which is C1-B. After repair, the elevation value of the upper surface of the mirror plate after being subjected to force should be C2-ξ. The deviation between the two is G=C1-B-(C2-ξ). If -0.50mm≤G≤0.50mm, the elevation meets the requirements. If G<-0.50mm, the elevation value of the repaired mirror plate is too high, and the thrust bearing seat needs to be processed. The processing amount is G. If G>0.50mm, the elevation value of the repaired mirror plate is too low, and a pad needs to be added to the lower part of the thrust bearing seat. The thickness of the pad is G. Step 4: Measurement after the thrust bearing is officially installed.

2. The method for determining the elevation of a thrust bearing modification structure for a large axial-flow propeller turbine unit according to claim 1, characterized in that: The thrust bearing housing (3) includes a flange base (2) and a top support (4). The flange base (2) and the flange face at the top of the thrust bracket (1) form a flange connection. The top support (4) is located at the top of the thrust bearing housing (3).

3. The method for determining the elevation of a thrust bearing modification structure for a large axial-flow propeller turbine unit according to claim 2, characterized in that: A first elevation limiting structure is provided between the top support (4) and the thrust bearing (10). The first elevation limiting structure includes a first hook plate (7) fixed to the outer wall of the top support (4) by a first bolt (6). The top hook of the first hook plate (7) cooperates with the first limiting groove (8) provided on the outer wall of the thrust bearing (10).

4. The method for determining the elevation of a large axial-flow propeller turbine thrust bearing modification structure according to claim 2, characterized in that: A second elevation limiting structure is provided between the top support (4) and the tile (9). The second elevation limiting structure includes a second hook plate (15) fixed to the outer wall of the top support (4) by a second bolt (16). The top hook of the second hook plate (15) cooperates with the second limiting groove (14) provided on the outer wall of the tile (9).

5. The method for determining the elevation of a large axial-flow propeller turbine thrust bearing modification structure according to claim 1, characterized in that: The outer walls of the toe (9) and the thrust plate (10) are fixedly connected by a connecting assembly, which is a connecting plate (12) fixed between the toe (9) and the thrust plate (10) by a third bolt (13).

6. The method for determining the elevation of a large axial-flow propeller turbine thrust bearing modification structure according to claim 1, characterized in that, The specific steps of step 4 are as follows: After the unit is turned around, measure the height A2 from the upper surface of the mirror plate to the bottom of the thrust oil groove under the stress state. Measure 4 points evenly distributed in the circumferential direction. Take the average value of the 4 points for the height difference A2. Compare the deviation between A1 and A2. The deviation should be within 0.50mm. Otherwise, make adjustments.

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