Assembly method of fir tree type blade

Abstract

The invention relates to an assembly method of fir tree type blades, in particular to an assembly method of blades. The invention aims to solve the problem that the assembly difficulty of the blade is increased due to long length and heavy weight of the conventional fir-tree-shaped blade. According to the method, the assembly quality completely meets the design requirement through the combination of vertical repairing and assembling of the blades and grouped installation, that is, two blades are installed in the 6 o'clock direction of a rotor, the radial datum line of the blades and the radial line of a wheel groove are located on the same straight line through the self weight of the blades, and the blades are repaired and assembled one by one; when the blades are formally assembled, a 180-degree symmetrical installation method is adopted, the problem that the rotor rotates due to the weight moment of the blades is solved, and the method is scientific, reasonable, high in operability and high in practicability. The invention belongs to the technical field of turbine rotor blade assembly.

Description

Technical Field

[0001] The invention relates to a blade assembly method, in particular to a fir-tree type blade assembly method, and belongs to the technical field of turbine rotor blade assembly. Background Art

[0002] The conventional assembly method for fir-tree blades is to first use a process whisking plate to repair them in a horizontal state, and then use a tightening mechanism at the bottom of the whisking plate to lift the blades so that the radial reference line of the blades and the radial line of the wheel groove are kept in a straight line. Then, they can be installed one by one when officially installed on the rotor.

[0003] However, as the power of steam turbines increases, the size of fir-tree blades also increases. The fir-tree blades of the final stage of the low-pressure rotor of a certain type of nuclear power steam turbine are 2000 mm long and weigh 120 kg. The blade body is designed with a tie rod boss, and the intermediate body gap S is required after the blade is assembled. 1 , Clearance between tie rod boss and rib S 2 , belt gap S 3 and throat size Sa meet the design requirements at the same time.

[0004] Due to the long length and heavy weight of the blade, it is greatly affected by the blade's gravity and gravity moment during the blade repair and installation process: the tightening mechanism of the conventional whisk plate cannot effectively lift the blade, and thus cannot be accurately repaired; secondly, when the blade is formally installed on the rotor, the method of installing it one by one gradually accumulates the number of blades, and the weight of the blades on the rotor continues to increase, causing the rotor to be affected by the weight moment, causing the rotor to rotate, thereby increasing the difficulty of blade assembly.

[0005] Therefore, the above-mentioned problems make it impossible to use conventional assembly methods for the blade. Providing a more reasonable assembly method to address the above-mentioned technical difficulties has become an urgent problem to be solved by those skilled in the art. Summary of the invention

[0006] The present invention aims at overcoming the above-mentioned deficiencies of the prior art and further provides an assembly method of a fir-tree-shaped blade.

[0007] The technical solution of the present invention is: a method for assembling a fir-tree-shaped blade, which is carried out according to the following steps:

[0008] Step 1: Sequentially number the blades and the wheel grooves on the rotor. The serial numbers of the blades and the wheel grooves correspond to each other one by one. The serial numbers of the blades and the wheel grooves are not allowed to be adjusted during the assembly process.

[0009] Step 2: Repair the blades

[0010] First, install the first and second blades into the corresponding wheel grooves, and adjust the gap S between the first and second blades.1 , Tie bar boss clearance S 2 , belt gap S 3 and throat size Sa;

[0011] Then, remove the first blade, install the third blade into the corresponding wheel groove, and adjust the gap S between the second blade and the third blade. 1 , Tie bar boss clearance S 2 , belt gap S 3 and throat size Sa; the subsequent blades to be repaired are repaired in the same way. When repairing two blades, the rotor needs to be rotated so that the two blades are at the 6 o'clock direction of the rotor;

[0012] Step 3: Install the blades on the rotor

[0013] Step 31: Divide all blades into several groups according to their serial numbers. The total weight moment of each group of blades must not cause the rotor to rotate.

[0014] Step 32: Install the first set of blades at the 6 o'clock position of the rotor;

[0015] Step 3: Rotate the rotor 180°, install another set of blades at the symmetrical position of the first set of blades, then rotate the rotor 180° again to install the second set of blades, and install the remaining blades in a similar manner.

[0016] Compared with the prior art, the present invention has the following effects:

[0017] The present invention achieves that the assembly quality fully meets the design requirements by combining the vertical repair and group installation of the blade 1, namely:

[0018] Two blades 1 are installed at the 6 o'clock position of the rotor 2. The blade 1's own weight is used to make the blade's radial reference line and the wheel groove's radial line in the same straight line, and the blades 1 are repaired one by one. When the blades 1 are formally assembled, a 180° symmetrical installation method is adopted to overcome the problem of the rotor rotating due to the weight moment of the blades 1. This method is scientific, reasonable, highly operational and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the blade 1 of the present invention;

[0020] Figure 2 A schematic diagram of a blade 1 repaired according to the present invention;

[0021] Figure 3 yes Figure 2 The intermediate gap S at A 1 Schematic diagram of

[0022] Figure 4 yes Figure 2The gap S between the reinforcement boss at the middle B 2 Schematic diagram of

[0023] Figure 5 yes Figure 2 The gap S of the belt at the middle C 3 Schematic diagram of

[0024] Figure 6 yes Figure 2 Schematic diagram of throat size Sa at D in the middle;

[0025] Figure 7 is a schematic diagram of installing the wedge-shaped gasket 3;

[0026] Figure 8 yes Figure 7 Sectional view in the P direction;

[0027] Fig. 9 is a schematic diagram of installing a boss gap gasket 4 between two adjacent blades 1;

[0028] Fig.10 It is a schematic diagram of the wedge-shaped gasket 3 pressing the blade 1 tightly;

[0029] Fig.11 It is a schematic diagram of the blade 1 being formally installed on the rotor 2.

[0030] In the figure: 1. blade; 2. rotor; 3. wedge-shaped gasket; 4. boss gap gasket. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and through specific implementations. Obviously, the implementations described below are only part of the implementations of the present invention, not all of the implementations. Based on the implementations in the present invention, all other implementations obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0032] Specific implementation method 1: Combination Figures 1 to 11 The present embodiment is described. The assembly method of a fir-tree-shaped blade of the present embodiment is specifically carried out in the following steps:

[0033] Step 1: The blades 1 and the wheel grooves on the rotor 2 are numbered sequentially. The serial numbers of the blades 1 and the wheel grooves correspond one to one. During the assembly process, the serial numbers of the blades 1 and the wheel grooves are not allowed to be adjusted.

[0034] Step 2: Repair blade 1

[0035] First, install the first and second blades 1 into the corresponding wheel grooves. Furthermore, from the steam outlet side of the blade to the steam inlet side of the blade, the blade 1 is installed in a clockwise direction. Adjust the intermediate gap S between the first blade 1 and the second blade 1. 1 , Clearance between tie rod boss and rib S 2 , belt gap S 3 and throat size Sa.

[0036] Then, remove the first blade 1, install the third blade 1 into the corresponding wheel groove, and adjust the gap S between the second blade 1 and the third blade 1. 1 , Clearance between tie rod boss and rib S 2 , belt gap S 3 and throat size Sa; the subsequent blades 1 to be repaired are repaired accordingly. When two blades 1 are repaired, the rotor 2 needs to be rotated so that the two blades 1 are at the 6 o'clock direction of the rotor 2. In this way, the radial reference line of the blade 1 is close to the radial line direction of the wheel groove by utilizing its own weight.

[0037] Step 3: Install blade 1 on rotor 2

[0038] Step 3: 1. Divide all blades 1 into several groups according to serial numbers. Further, each group of blades 1 includes 2 to 5 blades 1, and the total weight moment of each group of blades 1 must not cause the rotor 2 to rotate.

[0039] Step 32: Install the first set of blades 1 at the 6 o'clock position of the rotor 2. Furthermore, when viewed from the steam outlet side of the blades to the steam inlet side of the blades, the blades 1 are installed in a clockwise direction.

[0040] Step 33: rotate the rotor 2 180°, install another group of blades 1 at the symmetrical position of the first group of blades 1, and then rotate the rotor 2 180° again to install the second group of blades 1. The remaining blades 1 are installed in this way. By setting up in this way, the blades 1 are installed in groups in a 180° symmetrical manner, which can effectively avoid the problem of the rotor rotating due to the weight moment caused by the accumulation of blade weight.

[0041] Specific implementation method 2: Combination Figures 1 to 11 In this embodiment, the intermediate gap S is adjusted in step 2 of this embodiment. 1 , Clearance between tie rod boss and rib S 2 , belt gap S 3 The specific steps for calculating the throat size Sa are:

[0042] A1. Insert at least two wedge-shaped gaskets 3 into the gap between the bottom of the blade root and the wheel groove to tighten the blade 1.

[0043] Furthermore, a feeler gauge is used to check whether blade 1 is tightened. The specific operation process is: use a feeler gauge to check whether there is a gap where the bearing surfaces of the blade root and the bearing surfaces of the wheel groove collide. If the 0.02mm feeler gauge cannot enter, it is determined that the bearing surface of the blade root and the bearing surface of the wheel groove collide, and blade 1 is tightened.

[0044] A2. Insert the boss gap gasket 4 into the gap between the tie rod bosses of two adjacent blades 1. The tie rod boss gap S 2 The range is a~bmm, and the thickness of the boss gap gasket 4 is δ∈[a, b].

[0045] A3. Use a feeler gauge to check the gap between the non-load-bearing surface of the blade root and the non-load-bearing surface of the wheel groove. The gap difference on the left and right sides of the radial reference line of the blade 1 is required to be less than 0.02mm. If the gap difference is greater than 0.02mm, adjust the thickness δ of the boss gap gasket 4 until the gap difference is less than 0.02mm, ensuring that the radial reference line of the blade 1 and the radial line of the wheel groove are in a straight line.

[0046] A4. Use a feeler gauge to check the gap S between two adjacent blades 1. 1 , belt gap S 3 and throat size Sa, all values ​​should meet the design requirements. If not, grind the tie bar boss or belt, and repeat steps A1 to A3 until the intermediate body gap S 1 , Tie bar boss clearance S 2 , belt gap S 3 Until the values ​​of throat size Sa meet the design requirements.

[0047] Other components and connection methods are the same as those in the first embodiment.

[0048] Example:

[0049] Combination Figures 1 to 11 To illustrate this embodiment, 78 blades 1 need to be installed on the low-pressure rotor of a certain type of nuclear power steam turbine, and the operation is performed according to the following steps:

[0050] Step 1: The blades 1 and the wheel grooves on the rotor 2 are numbered sequentially from 1 to 78. The serial numbers of the blades 1 and the wheel grooves correspond one to one. The serial numbers of the blades 1 and the wheel grooves are not allowed to be adjusted during the assembly process. The serial numbers are arranged in a clockwise direction from the steam outlet side to the steam inlet side of the blades.

[0051] Step 2: Repair blade 1

[0052] First, install the first and second blades 1 into the corresponding wheel grooves, and adjust the gap S between the first blade 1 and the second blade 1. 1 , Tie bar boss clearance S 2 , belt gap S3 and throat size Sa.

[0053] Then, remove the first blade 1, install the third blade 1 into the corresponding wheel groove, and adjust the gap S between the second blade 1 and the third blade 1. 1 , Clearance between tie rod boss and rib S 2 , belt gap S 3 and throat size Sa; the subsequent blades 1 to be repaired are repaired accordingly. When the two blades 1 are repaired, the rotor 2 needs to be rotated so that the two blades 1 are at the 6 o'clock direction of the rotor 2.

[0054] Step 3: Install blade 1 on rotor 2

[0055] Step 3: 1. Divide all blades 1 into several groups according to their serial numbers. The total weight moment of each group of blades 1 must not cause the rotor 2 to rotate. The number of blades 1 in each group is shown in the following table:

[0056]

[0057]

[0058] Step 32: Install the first set of blades 1 at the 6 o'clock position of the rotor 2;

[0059] Step 33: Rotate the rotor 2 180°, install the ninth set of blades 1 at the symmetrical position of the first set of blades 1, then rotate the rotor 2 180° again to install the second set of blades 1, and install the remaining blades 1 in the same way until all blades 1 are installed.

[0060] The present invention has been disclosed as above in the form of a preferred embodiment, but it is not intended to limit the present invention. Any simple modification, equivalent changes and modifications made to the above implementation cases by any professional and technical personnel who do not deviate from the content of the technical solution of the present invention and based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for assembling a fir-tree-shaped blade, characterized in that: The method proceeds as follows: Step 1: sequentially number the blades (1) and the wheel grooves on the rotor (2), the serial numbers of the blades (1) and the serial numbers of the wheel grooves corresponding to each other, and the serial numbers of the blades (1) and the wheel grooves are not allowed to be adjusted during the assembly process; Step 2: Repair the blade (1) First, the first and second blades (1) are installed into the corresponding wheel grooves, and the intermediate body gap S1, the tie bar boss gap S2, the shroud gap S3 and the throat size Sa of the first blade (1) and the second blade (1) are adjusted; Then, remove the first blade (1), install the third blade (1) into the corresponding wheel groove, and adjust the intermediate body gap S1, the tie bar boss gap S2, the shroud gap S3 and the throat size Sa of the second blade (1) and the third blade (1); the blades (1) to be adjusted are adjusted in the same way. When adjusting the two blades (1), the rotor (2) needs to be rotated so that the two blades (1) are at the 6 o'clock direction of the rotor (2); Step 3: Install the blades (1) on the rotor (2) Step 3:

1. All blades (1) are divided into a number of groups according to their serial numbers, and the total weight moment of each group of blades (1) must not cause the rotor (2) to rotate; Step 32: Install the first set of blades (1) at the 6 o'clock position of the rotor (2); Step 3: Rotate the rotor (2) 180°, install another set of blades (1) at the symmetrical position of the first set of blades (1), then rotate the rotor (2) 180° again to install the second set of blades (1), and install the remaining blades (1) in the same manner.

2. The method for assembling a fir-tree-shaped blade according to claim 1, characterized in that: The specific steps of adjusting the intermediate body gap S1, the tie rod boss gap S2, the shroud gap S3 and the throat size Sa in step 2 are: A1. Insert at least two wedge-shaped gaskets (3) into the gap between the bottom of the blade root and the wheel groove to tighten the blade (1); A2, inserting a boss gap gasket (4) into the gap between the tie rod bosses of two adjacent blades (1), the range of the tie rod boss gap S2 is (a~b) mm, and the thickness of the boss gap gasket (4) is δ∈[a, b]; A3. Use a feeler gauge to check the gap between the non-load-bearing surface of the blade root and the non-load-bearing surface of the wheel groove. The difference in the gaps on the left and right sides of the radial reference line of the blade (1) is required to be less than 0.02 mm. If the difference in the gap is greater than 0.02 mm, adjust the thickness δ of the boss gap gasket (4) until the difference in the gap is less than 0.02 mm, ensuring that the radial reference line of the blade (1) and the radial line of the wheel groove are in a straight line. A4. Use a feeler gauge to check the intermediate body gap S1, shroud gap S3 and throat size Sa of two adjacent blades (1). The values ​​of each location should meet the design requirements. If not, grind the tie rod boss or shroud. After grinding, repeat steps A1 to A3 until the intermediate body gap S1, tie rod boss gap S2, shroud gap S3 and throat size Sa meet the design requirements.

3. The method for assembling a fir-tree-shaped blade according to claim 2, characterized in that: In the step 2, the blade (1) is installed in a clockwise direction when viewed from the steam outlet side of the blade to the steam inlet side of the blade.

4. The method for assembling a fir-tree-shaped blade according to claim 3, characterized in that: In step 31, each group of blades (1) comprises 2 to 5 blades (1).

5. The method for assembling a fir-tree-shaped blade according to claim 4, characterized in that: In step 32, when viewed from the steam outlet side of the blade to the steam inlet side of the blade, the blade (1) is installed in a clockwise direction.

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