A method for determining the height of a wedge plate in a runner room reconstruction of an axial flow propeller type hydroelectric generator set and a reconstruction and installation method

Abstract

The application discloses a kind of determination method and reconstruction installation method of runner room wedge plate elevation of axial flow variable pitch hydroelectric generator unit, and determination method of wedge plate elevation includes S1 before unit disassembly measurement seat ring upper flange elevation g;S2 during unit disassembly process after lifting and dismounting runner, measure top cover floating amount m;S3 according to the range n of guide vane end face design gap n min ~n max , top cover thickness a, guide vane height b, bottom ring thickness c, base ring thickness d, runner room middle ring thickness e, runner room lower ring thickness f, top cover subsidence amount m, total thickness c of bottom ring before processing, bottom ring machining allowance c1 determine the range of wedge plate and seat ring upper flange height difference h.Effective range of the elevation of the runner room wedge plate of the unit determined by the application is reliable;This method can directly obtain the installation elevation range of the wedge plate, which is convenient for intuitive adjustment and determination of the elevation;Using this method can effectively protect the guide vane end face gap, and avoid high cost and high difficulty processing in later period.

Description

Technical Field

[0001] The invention belongs to the technical field of hydropower station generator set reconstruction, and particularly relates to a method for determining the elevation of a wedge plate for reconstruction of a runner chamber of an axial-flow propeller-type hydro-turbine generator set and a reconstruction and installation method. Background Art

[0002] A hydropower station with an axial-flow propeller turbine had been in operation for nearly 40 years. The equipment and units were severely aged and performance had declined, necessitating a complete renovation and update. The turbine seat ring remained unchanged, while the top cover and movable guide vanes were returned to the factory for repair. The bottom ring, foundation ring, runner chamber middle ring, and runner chamber lower ring were replaced. Due to the need for coordination between new and old components during this renovation, any carelessness could result in the guide vane end face clearance failing to meet design requirements after installation. Excessive clearance could lead to significant water leakage, posing a safety hazard. Excessively small clearance could render the guide vanes inflexible, accelerating damage to the guide vane end face seals and even causing shear pins to break. Both issues are extremely costly and difficult to address. Therefore, a method for determining the bottom wedge plate elevation for runner chamber renovations of large axial-flow propeller turbines was proposed. Summary of the Invention

[0003] The purpose of the present invention is to address the deficiencies of the prior art. As one aspect of the present invention, a method for determining the elevation of the wedge plate for the runner chamber modification of an axial-flow propeller-type hydro-turbine generator set and a modification and installation method are proposed, which are used to determine the elevation of the wedge plate below the runner chamber during the modification process, ensure that the guide vane end face clearance is within the design requirements, and ensure the installation quality of the unit after modification.

[0004] One aspect of the present invention provides a method for determining the elevation of a wedge plate for a runner chamber reconstruction of an axial-flow propeller-type hydro-turbine generator set, comprising the following steps:

[0005] Before disassembling the S1 unit, measure the flange surface elevation g on the seat ring;

[0006] During the disassembly of the S2 unit, the floating amount of the top cover was measured after the runner was removed to estimate the sinking amount of the unit during the reinstallation process (m);

[0007] S3 is designed based on the range of the clearance n on the guide vane end face min ~n max , top cover thickness a, guide vane height b, bottom ring thickness c, base ring thickness d, runner chamber middle ring thickness e, runner chamber lower ring thickness f, top cover sinking amount m, bottom ring total thickness before machining c, bottom ring machining allowance c1 Determine the range of height difference h between wedge plate and flange surface on seat ring, h min =a+b+d+e+f+m+(c-c1)+n min , h max =a+b+d+e+f+m+c+n max ;

[0008] S4 calculates the range of the wedge plate elevation k, k min =gh max , kmax=gh min . .

[0009] Preferably, step S2 specifically includes the following steps:

[0010] Before disassembling the S21 unit, two dial indicators were installed on the movable guide vanes in different positions. The dial indicator base was adsorbed on the movable guide vanes, and the indicator needles were respectively against the anti-wear surface at the lowest part of the top cover and the anti-wear surface at the highest part of the bottom ring;

[0011] When the S22 unit is dismantled, the force conversion will transfer the weight of the rotating part to the brake first, and then to the foundation structure through the runner suspension. The force conversion will cause the top cover to float up;

[0012] After the S23 unit is disassembled, record the change in the readings of the two dial indicators of the same movable guide vane x i 、y i , get the top cover floating amount m at this position i =|x i +y i |;

[0013] S24 calculates the top cover floating amount m obtained from multiple different directions i Calculate the average value and obtain the top cover floating amount m.

[0014] Another aspect of the present invention provides a method for remodeling and installing a runner chamber of an axial-flow propeller-type hydro-turbine generator set, comprising the following steps:

[0015] Step 1: Dismantle the unit to be rebuilt. When removing the runner, determine the range of the wedge plate elevation k according to the above-mentioned method for determining the wedge plate elevation for the runner chamber reconstruction of the axial-flow propeller-type hydro-turbine generator set;

[0016] Step 2: Remove the top cover, movable guide vanes, bottom ring, foundation ring, runner chamber middle ring, and runner chamber lower ring in sequence. Do not remove the seat ring. Return the removed parts to the factory for repair, modification, or replacement.

[0017] Step 3: After the unit is returned to the factory for repair, renovation or replacement, reinstall the unit, which includes the following steps:

[0018] Step 3-1: First, place a wedge plate above the draft tube and adjust the height of the wedge plate so that the height of the wedge plate is within the range of the wedge plate height k determined in step 1.

[0019] Step 3-2 After hoisting the runner chamber lower ring, runner chamber middle ring and foundation ring in sequence, measure the elevation of the foundation ring and design the clearance n according to the guide vane end face. min ~n max, as well as the top cover thickness a, guide vane height b calculate the grinding amount of the bottom ring, grind the bottom ring and then hoist the bottom ring, and then hoist the movable guide vane and top cover.

[0020] Preferably, in step 3-1, the elevation of the wedge plate is adjusted so that the elevation of the wedge plate is equal to the median value of the range of the wedge plate elevation k determined in step 1.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a method for determining the elevation of a wedge plate for renovation of the runner chamber of an axial-flow propeller-type hydro-turbine generator set and a method for renovation and installation. The method determines the elevation of the bottom wedge plate for renovation of the runner chamber of the unit reliably; the method can directly derive the effective range of the wedge plate installation elevation, facilitating intuitive adjustment and determination of the elevation; the use of this method can effectively ensure the end face clearance of the guide vane, avoiding high cost and high difficulty processing in the later stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the runner chamber of the axial flow propeller type hydro-turbine generator set of the present invention.

[0024] Figure 2 for Figure 1 Schematic diagram of the enlarged structure of part A in the middle.

[0025] In the above drawings: 1. lower ring of the runner chamber; 2. middle ring of the runner chamber; 3. base ring; 4. bottom ring; 5. seat ring; 6. movable guide vane; 7. top cover; 8. wedge plate. DETAILED DESCRIPTION

[0026] 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.

[0027] See Figure 1 and Figure 2 , Figure 1 Schematic diagram of the structure of the runner chamber of the axial-flow propeller-type hydro-turbine generator set according to an embodiment of the present invention. Figure 2 for Figure 1 The enlarged structural diagram of part A in the middle shows the installation method and structure of the wedge plate in detail.

[0028] During generator set installation, wedge plate 8 is first placed above the tailwater pipe. Then, from bottom to top, the runner chamber lower ring 1, runner chamber middle ring 2, foundation ring 3, bottom ring 4, movable guide vanes 6, and top cover 7 are installed. Finally, the outer lower flange of the top cover is mounted on the upper flange of the seat ring. During the renovation, the unit's seat ring 5 was not replaced, and the elevation of the upper flange of the seat ring remains the same as before the repair. When determining the elevation of wedge plate 8, the alignment of the outer lower flange of the top cover with the upper flange of the seat ring after installation is complete must be considered, as well as the bottom ring machining allowance, the amount of top cover subsidence after unit force conversion, and the design requirements for the guide vane end clearance.

[0029] During the operation of the unit, the weight of the rotating parts acts on the thrust bearing, and is then transferred to the seat ring foundation through the thrust bracket, support cover, and top cover. However, during the installation of the unit, when the top cover changes from a state without external axial load to a state of bearing axial load after the installation of the rotating parts is completed, the top cover will sink to a certain extent. This sinking amount is manifested at the anti-wear surface at the lowest part of the top cover, which is an important factor affecting the end face clearance of the guide vane. This sinking amount is equivalent to the floating amount of the top cover when the unit is disassembled. When the unit is reinstalled after disassembly and modification, it needs to be taken into consideration to ensure the end face clearance of the movable guide vane after the unit is reinstalled.

[0030] Based on this idea, as a preferred embodiment of the present invention, this embodiment provides a method for determining the elevation of a wedge plate for the runner chamber reconstruction of an axial-flow propeller-type hydro-turbine generator set, comprising the following steps:

[0031] Before disassembling the S1 unit, measure the flange surface elevation g on the seat ring;

[0032] During the disassembly of the S2 unit, the floating amount of the top cover 7 is measured after the runner is removed to estimate the sinking amount m of the unit during the reinstallation process;

[0033] S3 is designed based on the range of the clearance n on the guide vane end face min ~n max , top cover thickness a, guide vane height b, bottom ring thickness c, base ring thickness d, runner chamber middle ring thickness e, runner chamber lower ring thickness f, top cover sinking amount m, bottom ring total thickness before machining c, bottom ring machining allowance c1 Determine the range of height difference h between wedge plate and flange surface on seat ring, h min =a+b+d+e+f+m+(c-c1)+n min , h max =a+b+d+e+f+m+c+n max ;

[0034] S4 calculates the range of the wedge plate elevation k, k min =gh max , kmax=gh min . .

[0035] During the unit design, in order to ensure the end face clearance of the movable guide vane 6, the thickness of the unit bottom ring must be confirmed and processed before leaving the factory. The total thickness of the bottom ring before processing is c, and the processing allowance is c1. This processing allowance provides a small amount of compensation for the installation elevation of the wedge plate.

[0036] The guide vane end face clearance is n(n min ~n max ), the top cover thickness is a, the guide vane height is b, the bottom ring thickness is c, the base ring thickness is d, the runner chamber middle ring thickness is e, the runner chamber lower ring thickness is f, the top cover sinking amount is m, and the height difference between the wedge plate and the seat ring upper flange surface is h.

[0037] When determining the installation elevation range of the wedge plate, the present invention mainly considers the following two limit states:

[0038] Consider the installation extreme case 1, when the wedge plate reaches the highest installation elevation, that is, when the height difference h is the smallest, the guide vane end face clearance should take the minimum design value n min , the bottom ring processing amount is the largest, then the factory thickness of the bottom ring is (c-c1), then h min =a+b+d+e+f+m+(c-c1)+n min ;

[0039] Consider the second extreme installation situation, when the wedge plate reaches the lowest installation elevation, that is, when the height difference h is the largest, the guide vane end face clearance should take the maximum design value n max , the bottom ring processing amount is 0, then the factory thickness of the bottom ring is c, then h max =a+b+d+e+f+m+c+n max .

[0040] In summary, the height difference between the top of the runner chamber modified wedge plate and the seat ring flange is h min and h max The design requirements of the guide vane end face clearance can be met when the values ​​are between 0.

[0041] In some preferred embodiments, step S2 specifically includes the following steps:

[0042] Before disassembling the S21 unit, two dial indicators were installed on the movable guide vanes in different positions. The dial indicator base was adsorbed on the movable guide vanes, and the indicator needles were respectively against the anti-wear surface at the lowest part of the top cover and the anti-wear surface at the highest part of the bottom ring;

[0043] When the S22 unit is dismantled, the force conversion will transfer the weight of the rotating part to the brake first, and then to the foundation structure through the runner suspension. The force conversion will cause the top cover to float up;

[0044] After the S23 unit is disassembled, record the change in the readings of the two dial indicators of the same movable guide vane x i 、y i, get the top cover floating amount m at this position i =|x i +y i |;

[0045] S24 calculates the top cover floating amount m obtained from multiple different directions i Calculate the average value and obtain the top cover floating amount m.

[0046] See also Figure 1 This embodiment provides a method for renovating and installing the runner chamber of an axial-flow propeller-type hydro-turbine generator set, comprising the following steps:

[0047] Step 1: Dismantle the unit to be rebuilt. When removing the runner, determine the range of the wedge plate elevation k according to the above-mentioned method for determining the wedge plate elevation for the runner chamber reconstruction of the axial-flow propeller-type hydro-turbine generator set;

[0048] Step 2: Remove the top cover, movable guide vanes, bottom ring, foundation ring, runner chamber middle ring, and runner chamber lower ring in sequence. Do not remove the seat ring. Return the removed parts to the factory for repair, modification, or replacement.

[0049] Step 3: After the unit is returned to the factory for repair, renovation or replacement, reinstall the unit, which includes the following steps:

[0050] Step 3-1: First, place a wedge plate above the draft tube and adjust the height of the wedge plate so that the height of the wedge plate is within the range of the wedge plate height k determined in step 1.

[0051] Step 3-2 After hoisting the runner chamber lower ring, runner chamber middle ring and foundation ring in sequence, measure the elevation of the foundation ring and design the clearance n according to the guide vane end face. min ~n max , as well as the top cover thickness a, guide vane height b calculate the grinding amount of the bottom ring, grind the bottom ring and hoist the bottom ring, then hoist the movable guide vane and top cover, and finally install the lower flange surface on the outside of the top cover on the upper flange surface of the seat ring.

[0052] In some preferred embodiments, in step 3-1, in order to achieve the optimal gap between the end faces of the movable guide vanes, in this embodiment, when adjusting the elevation of the wedge plate, the elevation of the wedge plate is made equal to the median value of the range of the wedge plate elevation k determined in step 1.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for determining the elevation of a wedge plate for the runner chamber reconstruction of an axial-flow propeller-type hydro-turbine generator set, characterized in that: The following steps are involved: Before disassembling the S1 unit, measure the flange surface elevation g on the seat ring; During the disassembly of the S2 unit, the floating amount of the top cover was measured after the runner was removed to estimate the sinking amount of the unit during the reinstallation process (m); S3 is designed based on the range of the clearance n on the guide vane end face min ~n max , top cover thickness a, guide vane height b, bottom ring thickness c, base ring thickness d, runner chamber middle ring thickness e, runner chamber lower ring thickness f, top cover sinking amount m, bottom ring total thickness before machining c, bottom ring machining allowance c1 Determine the range of height difference h between wedge plate and flange surface on seat ring, h min =a+b+d+e+f+m+(c-c1)+n min , h max =a+b+d+e+f+m+c+n max ; S4 calculates the range of the wedge plate elevation k, k min =gh max , k max =gh min .

2. The method for determining the elevation of the wedge plate for the runner chamber reconstruction of an axial-flow propeller-type hydro-turbine generator set according to claim 1 is characterized in that: Step S2 specifically includes the following steps: Before disassembling the S21 unit, two dial indicators were installed on the movable guide vanes in different directions. The dial indicator base was adsorbed on the movable guide vanes, and the indicator needles were respectively against the anti-wear surface of the lowest part of the top cover and the anti-wear surface of the highest part of the bottom ring; When the S22 unit is dismantled, the force conversion will transfer the weight of the rotating part to the brake first, and then to the foundation structure through the runner suspension. The force conversion will cause the top cover to float up; After the S23 unit is disassembled, record the change in the readings of the two dial indicators of the same movable guide vane x i 、y i , get the top cover floating amount m at this position i =|x i +y i |; S24 calculates the top cover floating amount m obtained from multiple different directions i Calculate the average value and obtain the top cover floating amount m.

3. A method for renovating and installing the runner chamber of an axial-flow propeller-type hydro-turbine generator set, characterized in that: The following steps are involved: Step 1: Dismantle the unit to be modified. When removing the runner, Determine the range of the wedge plate elevation k according to the method for determining the wedge plate elevation for the runner chamber reconstruction of an axial-flow propeller-type hydro-turbine generator set according to claim 1 or 2; Step 2: Remove the top cover, movable guide vanes, bottom ring, foundation ring, runner chamber middle ring, and runner chamber lower ring in sequence. Do not remove the seat ring. Return the removed parts to the factory for repair, modification, or replacement. Step 3: After the unit is returned to the factory for repair, renovation or replacement, reinstall the unit, which includes the following steps: Step 3-1: First, place a wedge plate above the draft tube and adjust the height of the wedge plate so that the height of the wedge plate is within the range of the wedge plate height k determined in step 1. Step 3-2: After hoisting the runner chamber lower ring, runner chamber middle ring and foundation ring in sequence, measure the elevation of the foundation ring and design the clearance n according to the guide vane end face. min ~n max , as well as the top cover thickness a, guide vane height b calculate the grinding amount of the bottom ring, grind the bottom ring and then hoist the bottom ring, and then hoist the movable guide vane and top cover.

4. The method for renovating and installing the runner chamber of an axial-flow propeller-type hydro-turbine generator set according to claim 3 is characterized in that: In step 3-1, the elevation of the wedge plate is adjusted so that the elevation of the wedge plate is equal to the median value of the range of the wedge plate elevation k determined in step 1.

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