Nuclear power plant gravel filter locking tool and method

Abstract

The invention discloses a nuclear power plant gravel filter locking tool and method, the tool comprises an extension shaft, a pair of fixing plates, a pull rod and a pull rod positioning nut, a pair of clamps, a clamp bolt and a nut, an extension shaft positioning bolt and an extension shaft positioning nut. The invention can solve the problem that the gravel filter cannot be repaired due to the self-rotation of the equipment and the electric head under the impact of a strong water flow. The novel tool is used for intervention to extend the transmission shaft and lock the extension shaft to achieve the purpose of locking the vehicle, avoid direct force on the transmission shaft, and cause damage to the surface, interior and yoke of the transmission shaft, and free the on-site operation from the limitation of small space, increase the on-site operability, and increase the force-bearing area. The tool can be used to fix the transmission shaft under the condition of continuous circulation of water, so as to achieve the purpose of repairing the worm of the reducer.

Description

Technical Field

[0001] The invention relates to the field of nuclear power, and in particular to a tool and method for locking a gravel filter in a nuclear power plant. Background Art

[0002] The gravel filter of a nuclear power plant is installed on the vertical pipe section of the cooling water inlet of each row of the condenser. Each unit is equipped with four gravel filters. The mesh diameter of the gravel filter is 5mm. Its function is to remove gravel, marine organisms and debris in the cooling water to prevent them from entering the condenser and causing damage to the condenser and destroying the condenser vacuum. For example, the model of the gravel filter No. 3 / 4 / 5 / 6 of Yangjiang Nuclear Power Plant is EDF-2800C, and the supplier is Jiangsu Electric Power Assembly Co., Ltd. Figure 1 The EDF-2800C type sewage bucket rotary backwash gravel filter adopts the principle of partitioned enhanced backwashing and sewage discharge. The mesh core 103 is connected to the power equipment 102 such as the reducer and the electric head through the transmission shaft 101. The mesh core 103 is divided into a number of independent filter chambers evenly distributed in the circumference and fixedly assembled with the shell 105, and has a built-in step-by-step rotating sewage bucket. The differential pressure monitoring device 106 or the timing program triggers the automatic backwashing program, opens the electric sewage valve 107, and the positioning measurement and control device controls the step-by-step rotation of the sewage bucket so that the sewage bucket opening is aligned with each filter chamber of the mesh core 103 in turn, making full use of the turbulence formed by the special filter chamber and the effective pressure head formed by the differential pressure of the condenser cooling water inlet and outlet pipes, realizing the fixed-frame enhanced backwashing of the filter chambers of the mesh core 103 one by one, and ensuring the clean operation of the mesh surface.

[0003] The effective flow diameter of the gravel filter is 2800mm and the rated flow rate is 15m 3 / s, operating pressure 2.4bar, water flows through the gravel filter into the condenser water chamber, causing great disturbance to the gravel filter transmission system. When the electric head brake of the transmission system fails or the reducer fails, the water flow impacts the sewage bucket and rotates, and the upstream transmission shaft of the transmission system swings or rotates with the sewage bucket. The water flow impacts different sewage buckets and transmission shafts with different swing or rotation amplitudes. Gravel filter reducer failure, reducer worm shaft disengagement or electric head failure will cause the fixed backwash function of this gravel filter to fail. If the reducer cannot be restored for a long time, the pressure difference of the gravel filter will continue to rise, which will cause the circulating water pump to trip and the generator set to reduce power. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a nuclear power plant gravel filter locking tool in view of the defect of the prior art that the gravel filter cannot be locked smoothly when the electric head brake fails or the reducer fails.

[0005] The technical solution adopted by the present invention to solve its technical problems is: construct a nuclear power plant gravel filter locking tool, including an extension shaft, a pair of fixing plates, a fixing plate tie rod and a tie rod positioning nut, a pair of clamps, a clamp bolt and a nut, an extension shaft positioning bolt and an extension shaft positioning nut, the extension shaft is provided with a transmission shaft connecting hole corresponding to the end cover mounting hole on the transmission shaft of the gravel filter, the extension shaft positioning bolt can be installed in the transmission shaft connecting hole and the end cover mounting hole and locked by the extension shaft positioning nut to achieve coaxial docking of the extension shaft and the transmission shaft, the pair of fixing plates are arranged opposite to each other up and down and are connected by a plurality of fixing plate tie rods and locked by the tie rod positioning nut, the pair of fixing plates can be distributed on both sides of the extension shaft and are arranged close to the transmission shaft yoke, and the side of the fixing plate is provided with a clamp installation opening to install the clamp and limit the swing range of the clamp;

[0006] Each of the clamps includes a clamping portion and two fixing ears connected to both ends of the clamping portion. The clamping portions of the pair of clamps jointly clamp the extension shaft. The fixing ears of the pair of clamps are locked by clamp bolts and nuts, and the two fixing ears of each clamp extend out of the pair of fixing plates from the clamp mounting openings of the pair of fixing plates.

[0007] Preferably, a groove is processed on the inner side of each of the clamps and / or a groove is processed on the outer peripheral wall of the extension shaft to increase the friction force when the clamps are in contact with the extension shaft.

[0008] Preferably, the fixing plate is a rectangular plate, and an observation window for the power equipment is provided in the middle of the fixing plate.

[0009] Preferably, it also includes a tie rod reinforcement rib, the number of the fixed plate tie rods is multiple, the multiple fixed plate tie rods are arranged around the observation window, and the two fixed plate tie rods on both sides of the clamp installation port are connected by the tie rod reinforcement rib, and the fixing ear of the clamp is restricted in the clamp installation port by the tie rod reinforcement rib and cannot fall out.

[0010] Preferably, it also includes a fixing block and a clamp limiting screw, wherein the fixing block is installed on a side of one of the fixing plates facing away from the other fixing plate and close to the clamp mounting port, and the clamp limiting screw passes through the fixing block and extends into the projection area where the clamp mounting port is located and faces the fixing ear of the clamp.

[0011] Another aspect of the present invention is to construct a method for locking a nuclear power plant gravel filter, which is implemented based on the aforementioned tool, and the method comprises:

[0012] Extension shaft installation step: after removing the end cover of the transmission shaft, install the extension shaft positioning bolt into the transmission shaft connecting hole and the end cover mounting hole, and lock it with the extension shaft positioning nut to achieve coaxial docking of the extension shaft and the transmission shaft;

[0013] The fixing plate installation step: a pair of fixing plates are arranged vertically and horizontally and distributed on both sides of the extension shaft and close to the transmission shaft yoke, and the pair of fixing plates are connected by a plurality of fixing plate tie rods and locked by tie rod positioning nuts;

[0014] Clamp installation steps: use the clamping parts of the pair of clamps to clamp the extension shaft together, and make the two fixing ears of each clamp extend out of the pair of fixing plates from the clamp installation openings of the pair of fixing plates respectively, and lock the fixing ears of the pair of clamps by clamp bolts and nuts.

[0015] Preferably, between the fixing plate installation step and the fixture installation step, the method further includes:

[0016] The steps for installing the clamp limit screw are as follows: install a fixing block on one of the fixing plates, which is away from the other fixing plate and close to the clamp mounting port; pass the clamp limit screw through the fixing block and extend it into the projection area where the clamp mounting port is located and face the fixing ear of the clamp; and adjust the clamp limit screw to the maximum limit.

[0017] Preferably, in the clamp installation step, the clamp bolts and nuts are not tightened temporarily, and the tie rod reinforcement ribs are first connected between the two fixed plate tie rods on both sides of the clamp installation port, and then the clamp bolts and nuts are tightened to make the clamp hold the extension shaft, and at the same time, the clamp limit screws are adjusted to gradually lock the extension shaft.

[0018] The nuclear power plant gravel filter locking tool and method of the present invention have the following beneficial effects: it can solve the problem that the gravel filter cannot be repaired due to the self-rotation of the equipment under the strong water flow impact, and the new tool is used to intervene, extend the transmission shaft, and lock the extension shaft to achieve the purpose of locking the vehicle, avoid direct force on the transmission shaft, cause damage to the surface, interior and yoke of the transmission shaft, and free the on-site operation from the limitation of small space, increase on-site operability, and increase the force-bearing area. This tool can be used to fix the transmission shaft while continuously circulating water, so as to achieve the purpose of repairing the reducer and the electric head. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative work:

[0020] Figure 1 It is a schematic diagram of the structure of the sewage bucket rotary backwash gravel filter;

[0021] Figure 2 This is one of the structural schematic diagrams of the nuclear power plant gravel filter locking tool after installation of the present invention;

[0022] Figure 3 This is the second structural schematic diagram of the nuclear power plant gravel filter locking tool after installation of the present invention;

[0023] Figure 4 It is a structural schematic diagram of the fixed plate;

[0024] Figure 5 It is a schematic diagram of the structure of the fixture. DETAILED DESCRIPTION

[0025] In order to solve the problem that the gravel filter cannot be locked smoothly when the electric head brake fails or the reducer fails, the present invention provides a nuclear power plant gravel filter locking tool and method, which uses an extension shaft to extend the transmission shaft and locks the extension shaft to achieve the purpose of locking the vehicle.

[0026] The present invention is described in more detail. Typical embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solutions of the present application, rather than limitations on the technical solutions of the present application. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0027] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may also be a centered element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a centered element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0029] Embodiment 1

[0030] refer to Figure 2-3 The main material of the nuclear power plant gravel filter locking tool of this embodiment is carbon steel, and the locking tool specifically includes an extension shaft 1, a pair of fixing plates 2, a fixing plate tie rod 3 and a tie rod positioning nut 9, a pair of clamps 4, a clamp bolt and a nut, an extension shaft positioning bolt and an extension shaft positioning nut 5, a fixing block 7 and a clamp limit screw 8. 100 in the figure represents the extension shaft part, and it should be noted that the size and proportion of each structure in the figure are only for illustration.

[0031] The extension shaft 1 is used to bear the friction force of the clamp 4, and at the same time transmit it to the transmission shaft through the extension shaft positioning bolt. The extension shaft 1 has the same outer diameter as the transmission shaft, and is provided with a transmission shaft connecting hole corresponding to the end cover mounting hole on the transmission shaft of the gravel filter. The extension shaft positioning bolt can be installed in the transmission shaft connecting hole and the end cover mounting hole and locked through the extension shaft positioning nut 5 to achieve coaxial docking of the extension shaft 1 and the transmission shaft. Specifically, when installing the extension shaft 1, it is necessary to first remove the end cover, then install the extension shaft positioning bolt into the end cover mounting hole, then align the extension shaft 1 with the extension shaft positioning bolt, and then tighten the extension shaft positioning nut 5. There are 8 end cover mounting holes on the transmission shaft. In theory, selecting 8 extension shaft positioning bolts can make the connection between the extension shaft 1 and the transmission shaft more stable, but considering the installation time, selecting 4 extension shaft positioning bolts is sufficient.

[0032] refer to Figure 4 , the fixed plate 2 is a rectangular plate. A fixture installation opening 21 is provided on the side of the fixed plate 2 to limit the swing range of the fixture 4, which is convenient for the installation of the fixture 4 and limits the swing range of the fixture 4 after installation. The fixture installation opening 21 is specifically a rectangular notch. An observation window 22 for power equipment such as a reducer and an electric head is provided in the middle of the fixed plate 2. The size and dimensions of the observation window 22 can meet the requirements that the fixed plate 2 can be set close to the transmission shaft yoke and does not interfere with the reducer and the motor. The fixed plate 2 bears the main impact force. The design adopts a 30mm thick steel plate to increase sufficient strength. 21 bolt holes are provided on the fixed plate 2 for installing the fixed plate tie rod 3. Accordingly, the number of the fixed plate tie rod 3 is 21, and the fixed plate tie rod 3 and the yoke jointly position the fixed plate 2. It can be understood that the number and size of the fixed plate tie rod 3 can be appropriately changed according to the actual space and impact force. After completing the coaxial docking of the extension shaft 1 and the transmission shaft, the fixing plate 2 can be installed, and the pair of fixing plates 2 can be hoisted so that they are distributed on both sides of the extension shaft 1 and are set close to the transmission shaft yoke. A pair of fixing plates 2 are set up opposite each other, connected by multiple fixing plate tie rods 3 and locked by tie rod positioning nuts 9. The fixing plate tie rods 3 can accurately position the fixing plate 2, and the positions of the tie rod positioning nuts 9 and the fixing plate 2 can be adjusted so that the fixing plate 2 is fully in contact with the yoke and the structural stability is maintained.

[0033] refer to Figure 5 In this embodiment, the structures and sizes of the two clamps 4 are completely consistent. Each of the clamps 4 includes a clamping portion that is close to a semicircular shape and two fixing ears connected to the two ends of the clamping portion. The clamping portions of the pair of clamps 4 are close to a full circle but not a full circle after being combined, so that the reserved portion can increase the clamping space for clamping and holding the extension shaft 1 together. The fixing ears of the pair of clamps 4 are locked by clamp bolts and nuts. The clamp bolts and nuts are mainly tightened slowly to finally clamp the extension shaft 1. The two fixing ears of each of the clamps 4 extend out of the pair of fixing plates 2 from the clamp mounting openings 21 of the pair of fixing plates 2. Preferably, a groove is processed on the inner side of each of the clamps 4 and / or a groove is processed on the outer peripheral wall of the extension shaft 1. For example, the processed grooves all extend along the axial direction of the extension shaft 1. By processing the grooves, the friction force when the clamp 4 and the extension shaft 1 are fitted can be increased.

[0034] In this embodiment, the plurality of fixing plate tie rods 3 are arranged around the observation window 22, and the two fixing plate tie rods 3 on both sides of the clamp installation opening 21 are connected by the tie rod reinforcement ribs 6. The tie rod reinforcement ribs 6 are mainly used to increase the strength of the fixing plate 2 at the clamp installation opening 21, and can limit the movement of the clamp 4 in the axial direction of the extension shaft 1 to prevent the clamp 4 from coming out.

[0035] The fixing block 7 is installed on one side of the fixing plates 2 that is away from the other fixing plate 2 and close to the fixture installation opening 21. The fixture limit screw 8 passes through the fixing block 7 and extends into the projection area where the fixture installation opening 21 is located and faces the fixing ear of the fixture 4. The fixture limit screw 8 is used to gradually adjust the swing amplitude of the fixture 4 after the fixture is installed, and finally fix it in position.

[0036] When using this tool, the reducer or electric head has lost its function, and the transmission shaft swings or rotates under the action of water flow. Use this tool to fix the clamp through the fixing plate 2 and the clamp limit screw 8, and the clamp 4 tightens the extension shaft 1. The friction force that increases during the clamping process of the clamp 4 hinders the movement of the extension shaft 1. Since the extension shaft 1 and the transmission shaft are fixed as a whole by the extension shaft positioning bolts, the purpose of fixing the transmission shaft and locking the vehicle is achieved, creating conditions for repairing the reducer and electric head.

[0037] The installation and operation process of the tool of this embodiment is specifically as follows: remove the transmission shaft end cover and screws, and when the transmission shaft is relatively stable, install the extension shaft positioning bolts and the extension shaft 1, and lock them with the extension shaft positioning nuts 5; hoist the upper and lower two fixing plates 2, the fixing plate 2 is close to the external yoke of the transmission shaft, and the fixing plate 2 is fixed by the fixing plate tie rod 3 and the tie rod positioning nut 9. There is a tie rod positioning nut 9 on both the upper and lower surfaces of the fixing plate 2, and the position of the fixing plate 2 is adjusted to the most stable by adjusting the tie rod positioning nut 9; a fixing block 7 is pre-installed at the bottom of the lower fixing plate 2, for example, the fixing block 7 can be installed by welding or bolt fixing, and after the fixing plate 2 is installed, the clamp limit screw 8 is installed and adjusted to the maximum limit; install the clamp 4, and do not tighten it temporarily when the clamp bolts and nuts are installed, and first install the tie rod reinforcement rib 6 to prevent the transmission shaft from swinging and causing the clamp 4 to fall out; then tighten the clamp bolts and nuts to make the clamp hold the extension shaft 1 tightly, and at the same time adjust the clamp limit screw 8 to gradually lock the extension shaft 1, so that the clamp 4 is finally stationary. The gravel filter is locked and fixed in position.

[0038] The present invention achieves the purpose of locking the vehicle by extending the transmission shaft and locking the transmission shaft extension shaft. It is fixed on the yoke through a fixing plate, which is safe and reliable, and has reserved installation space for the electric head. The extension shaft can be gradually locked through the fixture block positioning screws and fixture bolts and nuts to prevent the equipment from being subjected to a large impact and damage to the equipment.

[0039] Embodiment 2

[0040] Based on the same inventive concept, the second embodiment of the present invention also constructs a method for locking a nuclear power plant gravel filter, which is implemented based on the tool described in the first embodiment. The method includes:

[0041] Extension shaft installation steps: After removing the end cover of the transmission shaft, install the extension shaft positioning bolt in the transmission shaft connecting hole and the end cover mounting hole, and lock it with the extension shaft positioning nut 5 to achieve coaxial docking of the extension shaft 1 and the transmission shaft.

[0042] The fixing plate installation steps are as follows: a pair of fixing plates 2 are arranged vertically opposite to each other and distributed on both sides of the extension shaft 1 and close to the transmission shaft yoke, and a pair of fixing plates 2 are connected by multiple fixing plate tie rods 3 and locked by tie rod positioning nuts 9.

[0043] The steps for installing the clamp limit screw are as follows: install a fixing block 7 on the side of one of the fixing plates 2 that is away from the other fixing plate 2 and close to the clamp mounting port 21, and then extend the clamp limit screw 8 through the fixing block 7 into the projection area where the clamp mounting port 21 is located and face the fixing ear of the clamp 4, and adjust the clamp limit screw 8 to the maximum limit.

[0044] Clamp installation steps: use the clamping parts of the pair of clamps 4 to jointly clamp the extension shaft 1, and make the two fixing ears of each clamp 4 extend out of the pair of fixing plates 2 from the clamp installation openings 21 of the pair of fixing plates 2, respectively, and lock the fixing ears of the pair of clamps 4 by clamp bolts and nuts, wherein the clamp bolts and nuts are not tightened temporarily when they are installed, first connect the tie rod reinforcement rib 6 between the two fixing plate tie rods 3 on both sides of the clamp installation opening 21, and then tighten the clamp bolts and nuts to make the clamp hold the extension shaft 1, and at the same time adjust the clamp limit screws 8 to gradually lock the extension shaft 1.

[0045] In summary, the nuclear power plant gravel filter locking tool and method of the present invention have the following beneficial effects: it can solve the problem that the gravel filter cannot be repaired due to the self-rotation of the equipment under the strong water flow impact, and the new tool is used to intervene, extend the transmission shaft, and lock the extension shaft to achieve the purpose of locking the vehicle, avoid direct force on the transmission shaft, and cause damage to the surface, interior and yoke of the transmission shaft, and free the on-site operation from the limitation of small space, increase on-site operability, and increase the force-bearing area. This tool can be used to fix the transmission shaft while continuously circulating water, so as to achieve the purpose of repairing the reducer and the electric head.

[0046] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A nuclear power plant gravel filter locking tool, characterized in that: The invention comprises an extension shaft (1), a pair of fixing plates (2), a fixing plate tie rod (3) and a tie rod positioning nut (9), a pair of clamps (4), a clamp bolt and a nut, an extension shaft positioning bolt and an extension shaft positioning nut (5); the extension shaft (1) is provided with a transmission shaft connecting hole corresponding to the end cover mounting hole on the transmission shaft of the gravel filter; the extension shaft positioning bolt can be installed in the transmission shaft connecting hole and the end cover mounting hole and locked by the extension shaft positioning nut (5) to achieve coaxial docking of the extension shaft (1) and the transmission shaft; the pair of fixing plates (2) are arranged vertically opposite to each other and are connected by a plurality of fixing plate tie rods (3) and locked by the tie rod positioning nut (9); the pair of fixing plates (2) can be distributed on both sides of the extension shaft (1) and are arranged close to the transmission shaft yoke; the side of the fixing plate (2) is provided with a clamp mounting opening (21) to install the clamp (4) and limit the swing range of the clamp (4); Each of the clamps (4) comprises a clamping portion and two fixing ears connected to both ends of the clamping portion, the clamping portions of the pair of clamps (4) clamp the extension shaft (1) together, the fixing ears of the pair of clamps (4) are locked by clamp bolts and nuts, and the two fixing ears of each of the clamps (4) extend out of the pair of fixing plates (2) from the clamp mounting openings (21) of the pair of fixing plates (2), respectively.

2. The vehicle locking tool according to claim 1, characterized in that: A groove is machined on the inner side of each clamp (4) and / or a groove is machined on the outer peripheral wall of the extension shaft (1) to increase the friction force when the clamp (4) and the extension shaft (1) are in contact.

3. The vehicle locking tool according to claim 1, characterized in that: The fixing plate (2) is a rectangular plate, and an observation window (22) for the power equipment is provided in the middle of the fixing plate (2).

4. The vehicle locking tool according to claim 3, characterized in that: It also includes a tie rod reinforcement rib (6), the number of the fixed plate tie rods (3) is multiple, the multiple fixed plate tie rods (3) are arranged around the observation window (22), and the two fixed plate tie rods (3) on both sides of the clamp installation opening (21) are connected through the tie rod reinforcement rib (6), and the fixing ear of the clamp (4) is restricted by the tie rod reinforcement rib (6) in the clamp installation opening (21) and cannot escape.

5. The vehicle locking tool according to claim 1, characterized in that: It also includes a fixing block (7) and a clamp limiting screw (8), wherein the fixing block (7) is installed on a side of one of the fixing plates (2) that is away from the other fixing plate (2) and close to the clamp mounting opening (21), and the clamp limiting screw (8) passes through the fixing block (7) and extends into the projection area where the clamp mounting opening (21) is located and faces the fixing ear of the clamp (4).

6. A method for locking a nuclear power plant gravel filter, characterized in that: Based on the tool implementation of claim 1, the method comprises: Extension shaft installation step: after removing the end cover of the transmission shaft, install the extension shaft positioning bolt in the transmission shaft connecting hole and the end cover installation hole, and lock it with the extension shaft positioning nut (5) to achieve coaxial docking of the extension shaft (1) and the transmission shaft; The fixing plate installation steps include: arranging a pair of fixing plates (2) vertically opposite to each other and distributed on both sides of the extension shaft (1) and arranged close to the transmission shaft yoke, connecting the pair of fixing plates (2) through a plurality of fixing plate tie rods (3) and locking them through tie rod positioning nuts (9); Clamp installation steps: use the clamping parts of the pair of clamps (4) to clamp the extension shaft (1) together, and make the two fixing ears of each clamp (4) extend out of the pair of fixing plates (2) from the clamp installation openings (21) of the pair of fixing plates (2), and lock the fixing ears of the pair of clamps (4) by clamp bolts and nuts.

7. The vehicle locking method according to claim 6, characterized in that: Between the fixing plate installation step and the fixture installation step, it also includes: The steps for installing the clamp limit screw are as follows: a fixing block (7) is installed on a side of one of the fixing plates (2) facing away from the other fixing plate (2) and close to the clamp installation opening (21); the clamp limit screw (8) is passed through the fixing block (7) and then extended into the projection area where the clamp installation opening (21) is located and faces the fixing ear of the clamp (4); and the clamp limit screw (8) is adjusted to the maximum limit.

8. The method according to claim 7, characterized in that In the clamp installation step, the clamp bolts and nuts are not tightened temporarily, and the tie rod reinforcement ribs (6) are first connected between the two fixed plate tie rods (3) on both sides of the clamp installation opening (21), and then the clamp bolts and nuts are locked so that the clamp holds the extension shaft (1), and at the same time, the clamp limit screws (8) are adjusted to gradually lock the extension shaft (1).

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