A steam generator eyelet thread hole repair device and method

Abstract

The present invention provides a steam generator eyelet threaded hole repairing device, comprising a support plate, a bottom plate, and an eyelet flange. The support plate is a rectangular parallelepiped structure. The bottom plate is a cylindrical structure. The bottom plate and the support plate are fixed to the outer side of the boss of the eyelet flange in sequence. The present invention also provides a steam generator eyelet threaded hole repairing method. The technical solution of the present invention has a simple structure, is easy to operate, has high efficiency, and is safe and reliable. The working process can simultaneously ensure the position and verticality after drilling, meeting the use requirements.

Description

Technical Field

[0001] The invention belongs to the technical field of mechanical maintenance, and in particular relates to a steam generator eyelet threaded hole repairing device and method. Background Art

[0002] Steam generators are nuclear power plant level 1 equipment and one of the three major equipment in nuclear power plants. During overhaul, the steam generator eyelets need to be opened for in-service inspection. During the opening and closing of the eyelets, the eyelet thread holes may be damaged. Thread damage will cause poor sealing and leakage accidents. At present, the thread damage problem is mainly solved by expanding the hole - re-tapping - installing a threaded bushing, but there are currently the following problems:

[0003] (1) The steam generator in the nuclear power plant is placed vertically and installed on vertical supports. The entire steam generator is inside a concrete containment vessel, and there is no stable and reliable operating platform at the eyelet repair station to ensure personnel safety;

[0004] (2) The steam generator has been installed in the nuclear island. Due to limited conditions, it can only be processed using portable equipment. The verticality and position accuracy cannot be guaranteed during the hole expansion process.

[0005] Based on this, it is urgent to design an improved steam generator eyelet threaded hole repair device and method. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a steam generator eyelet threaded hole repairing device and method to ensure the verticality and position accuracy during the hole expansion process.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A steam generator eyelet thread hole repair device comprises a support plate, a bottom plate and an eyelet flange. The support plate is a rectangular parallelepiped structure. The bottom plate is a cylindrical structure. The bottom plate and the support plate are fixed to the outer side of the boss of the eyelet flange in sequence.

[0009] The eyelet flange has 4 screw holes evenly distributed along the circumference, and the screw hole size is M24*3.

[0010] The center of the bottom plate is provided with a middle hole, which is concentric with the boss of the eyelet flange 4, and the fitting clearance is 1mm. The bottom plate is coaxially connected with the boss of the eyelet flange through the middle hole. The bottom plate is evenly provided with 4 screw holes outside the middle hole. Three of the screw holes are small screw holes, and the hole diameter is 24mm; the fourth screw hole is a large screw hole, and the hole diameter is 34mm. Screw holes A and screw holes B are symmetrically distributed in the horizontal direction on both sides of the large screw hole, and the size is M10.

[0011] Three countersunk holes are distributed on the upper part of the support plate, and their position arrangement and size are consistent with the three small screw holes of the bottom plate; a rectangular parallelepiped groove is opened above the countersunk holes of the support plate.

[0012] The countersunk holes of the support plate are connected with the small screw holes of the bottom plate and the screw holes of the eyelet flange in sequence through bolts. The size of the bolts is M24*3.

[0013] The support plate is made of carbon steel.

[0014] The steam generator eyelet threaded hole repair device is also provided with a positioning fixture. The positioning fixture is a rectangular parallelepiped structure and is fixed on the rectangular parallelepiped groove of the support plate. The positioning fixture is provided with two screw holes, namely screw hole C and screw hole D, whose position arrangement and size are respectively consistent with screw hole A and screw hole B on the bottom plate. The clearance between the bottom of the positioning fixture and the rectangular parallelepiped groove of the support plate is 0.1-0.2mm.

[0015] The two screw holes of the positioning fixture are fixedly connected to the bottom plate along the rectangular groove of the support plate by screws; the screw size is M10.

[0016] The magnetic drill is adsorbed on the support plate, and the drilling bit is fed to complete the hole enlargement work of the screw hole to be repaired.

[0017] The present invention also provides a method for repairing a steam generator eyelet threaded hole using the steam generator eyelet threaded hole repairing device, comprising the following steps:

[0018] 1) Clean the four screw holes of the eyelet flange and seal the eyelet flange with stainless steel tape to prevent foreign matter from entering the steam generator;

[0019] 2) Select the three small screw holes on the bottom plate for positioning, corresponding to the actual positions of the screw hole to be repaired and the other three screw holes, and align the bottom plate on the eyelet flange;

[0020] 3) Position the support plate on the bottom plate according to the actual positions of the three small screw holes on the bottom plate, connect the support plate, bottom plate and eyelet flange with three M24*3 bolts, and tighten the bolts;

[0021] 4) Use a feeler gauge to check the gap between the eyelet flange surface and the bottom plate surface, and between the support plate and the bottom plate to ensure the parallelism between the support plate and the bottom plate surface and the eyelet flange surface;

[0022] 5) Select a magnetic drill with roundness and verticality that meet the use requirements, and install a core rod with the same diameter as the screw hole to be repaired on its main shaft. Keep adjusting the position of the magnetic drill until the core rod can smoothly pass through the screw hole to be repaired. At this time, it means that the magnetic drill is in the correct installation position. Adsorb the magnetic drill on the support plate;

[0023] 6) Remove the mandrel, place the positioning fixture close to the bottom plate along the rectangular groove of the support plate, connect the positioning fixture to the bottom plate with two M10 screws, and tighten the screws;

[0024] 7) According to the hole expansion operation, use a magnetic drill to install the corresponding drill bit and perform it in stages. First, test drill on the positioning tooling. After each stage of hole expansion, check the position and verticality of the hole;

[0025] 8) After the bottom hole is expanded, conduct a visual inspection, including the bottom hole depth and diameter;

[0026] 9) Remove the repair tooling, visually inspect all screw holes, and perform go and no-go gauge checks;

[0027] 10) Tap the repaired bottom hole, and use a ruler close to the tap during the tapping process to ensure the verticality of the tap;

[0028] 11) Install the threaded bushing after tapping. After installation, check the verticality and position, and use the go and stop gauges to check;

[0029] 12) Work is completed and materials are cleared.

[0030] The beneficial effects achieved by the present invention are:

[0031] 1) The structure is simple and easy to operate. The working process can simultaneously ensure the position and verticality of the hole after drilling, meeting the use requirements;

[0032] 2) The tool is simple in design and easy to carry, and can be used for drilling work that cannot be moved or the operating space remains unchanged;

[0033] 3) High work efficiency, safety and reliability, indirectly reducing personnel radiation dose and greatly reducing operational risks;

[0034] 4) The present invention has reference significance for other similar screw hole repair works and has strong scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of the eyelet flange;

[0036] Figure 2 is a schematic diagram of the base plate;

[0037] Figure 3 It is the connection diagram of the base plate and the support plate;

[0038] Figure 4 It is the connection diagram of the support plate and the positioning fixture;

[0039] Figure 5 It is a schematic diagram of a steam generator eyelet thread hole repair device;

[0040] Figure 6 Schematic diagram of magnetic drill hole repair.

[0041] In the figure: 1 is a support plate; 2 is a bottom plate; 3 is a positioning tool; 4 is a steam generator eyelet flange; 5 is a magnetic drill; 6 is a screw hole A; 7 is a screw hole B; 8 is a screw hole C; 9 is a screw hole D. DETAILED DESCRIPTION

[0042] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0043] like Figure 1-Figure 6 As shown, the present invention provides a steam generator eyelet thread hole repair device, comprising a support plate 1, a bottom plate 2, and an eyelet flange 4. The support plate 1 is a rectangular parallelepiped structure. The bottom plate 2 is a cylindrical structure. The bottom plate 2 and the support plate 1 are fixed to the outer side of the boss of the eyelet flange 4 in sequence.

[0044] The eyelet flange 4 has 4 screw holes evenly distributed along the circumferential direction, and the size of the screw holes is M24*3.

[0045] The center of the bottom plate 2 is provided with a middle hole, which is concentric with the boss of the eyelet flange 4, and the fitting clearance is 1mm. The bottom plate 2 is coaxially connected with the boss of the eyelet flange 4 through the middle hole. The bottom plate 2 is evenly provided with 4 screw holes outside the middle hole. Three of the screw holes are small screw holes, and the hole diameter is 24mm; the fourth screw hole is a large screw hole, and the hole diameter is 34mm. Screw holes A6 and screw holes B7 are symmetrically distributed in the horizontal direction on both sides of the large screw hole, and the size is M10.

[0046] Three countersunk holes are distributed on the upper part of the support plate 1 , and their positions, arrangements and sizes are consistent with the three small screw holes of the bottom plate 2 ; a rectangular parallelepiped groove is opened above the countersunk holes of the support plate 1 .

[0047] The countersunk holes of the support plate 1 are connected with the small screw holes of the bottom plate 2 and the screw holes of the eyelet flange 4 in sequence through bolts. The size of the bolts is M24*3.

[0048] The support plate 1 is made of carbon steel.

[0049] The steam generator eyelet threaded hole repair device is also provided with a positioning fixture 3. The positioning fixture 3 is a rectangular parallelepiped structure and is fixed on the rectangular parallelepiped groove of the support plate 1. The positioning fixture 3 is provided with two screw holes, namely screw hole C8 and screw hole D9, whose position arrangement and size are respectively consistent with screw hole A6 and screw hole B7 on the bottom plate. The clearance between the bottom of the positioning fixture 3 and the rectangular parallelepiped groove of the support plate 1 is 0.1-0.2mm.

[0050] The two screw holes of the positioning fixture 3 are fixedly connected to the bottom plate 2 along the rectangular groove of the support plate 1 by screws; the size of the screws is M10.

[0051] The magnetic drill 5 is adsorbed on the support plate 1, and the enlarging work of the screw hole to be repaired is completed through the feeding movement of the drill bit.

[0052] like Figure 6 As shown, the present invention also provides a method for repairing a steam generator eyelet threaded hole using the steam generator eyelet threaded hole repairing device, comprising the following steps:

[0053] 1) Clean the four screw holes of the eyelet flange 4 and seal the eyelet flange 4 with stainless steel tape to prevent foreign matter from entering the steam generator;

[0054] 2) Select the three small screw holes of the bottom plate 2 for positioning according to the actual positions of the screw hole to be repaired and the other three screw holes, and align the bottom plate 2 on the eyelet flange 4;

[0055] 3) Position the support plate 1 on the bottom plate 2 according to the actual positions of the three small screw holes of the bottom plate 2, connect the support plate 1, the bottom plate 2 and the eyelet flange 4 with three M24*3 bolts, and tighten the bolts;

[0056] 4) Use a feeler gauge to check the gap between the surface of the eyelet flange 4 and the surface of the bottom plate 2, and between the support plate 1 and the bottom plate 2, to ensure the parallelism between the surface of the support plate 1 and the bottom plate 2 and the surface of the eyelet flange 4;

[0057] 5) Select a magnetic drill 5 whose roundness and verticality meet the use requirements, and install a core rod with the same diameter as the screw hole to be repaired on its main shaft. Keep adjusting the position of the magnetic drill 5 until the core rod can smoothly pass through the screw hole to be repaired. At this time, it means that the magnetic drill 5 is in the correct installation position, and the magnetic drill 5 is adsorbed on the support plate 1;

[0058] 6) Remove the mandrel, place the positioning fixture 3 close to the bottom plate 2 along the rectangular groove of the support plate 1, connect the positioning fixture 3 to the bottom plate 2 with two M10 screws, and tighten the screws;

[0059] 7) According to the hole enlarging operation, use the magnetic drill 5 to install the corresponding drill bit and perform it in stages. First, test drill on the positioning tool 3. After each stage of hole enlarging, check the position and verticality of the hole;

[0060] 8) After the bottom hole is expanded, conduct a visual inspection, including the bottom hole depth and diameter;

[0061] 9) Remove the repair tooling, visually inspect all screw holes, and perform go and no-go gauge checks;

[0062] 10) Tap the repaired bottom hole, and use a ruler close to the tap during the tapping process to ensure the verticality of the tap;

[0063] 11) Install the threaded bushing after tapping. After installation, check the verticality and position, and use the go and stop gauges to check;

[0064] 12) Work is completed and materials are cleared.

[0065] The beneficial effects achieved by the present invention are:

[0066] 1) The structure is simple and easy to operate. The working process can simultaneously ensure the position and verticality of the hole after drilling, meeting the use requirements;

[0067] 2) The tool is simple in design and easy to carry, and can be used for drilling work that cannot be moved or the operating space remains unchanged;

[0068] 3) High work efficiency, safety and reliability, indirectly reducing personnel radiation dose and greatly reducing operational risks;

[0069] 4) The present invention has reference significance for other similar screw hole repair works and has strong scalability.

Claims

1. A steam generator eyelet thread hole repair device, characterized in that: The invention comprises a support plate (1), a base plate (2) and an eyelet flange (4); the support plate (1) is a rectangular parallelepiped structure and is made of carbon steel; the base plate (2) is a cylindrical structure; the base plate (2) and the support plate (1) are fixed in sequence on the outer side of the boss of the eyelet flange (4); the eyelet flange (4) has 4 screw holes evenly distributed along the circumferential direction, and the screw hole sizes are all M24*3; a middle hole is arranged at the center of the base plate (2), and the middle hole is concentric with the boss of the eyelet flange (4), and the fitting clearance is 1 mm; the base plate (2) is connected to the eyelet flange (4) through the middle hole. The bosses of the eyelet flange (4) are coaxially connected; four screw holes are evenly arranged on the outside of the middle hole of the bottom plate (2); three of the screw holes are small screw holes, and the hole diameter is 24 mm; the fourth screw hole is a large screw hole, and the hole diameter is 34 mm; screw holes A (6) and screw holes B (7) are symmetrically distributed on both sides of the large screw hole in the horizontal direction, and the sizes of screw holes A (6) and screw holes B (7) are both M10; the steam generator eyelet threaded hole repairing device is used in conjunction with a magnetic drill (5), and the magnetic drill (5) is adsorbed on the support plate (1).

2. The steam generator eyelet threaded hole repair device according to claim 1, characterized in that: The upper part of the support plate (1) is provided with three countersunk holes, and the positions, arrangements and sizes of the countersunk holes are consistent with the three small screw holes of the bottom plate (2); A rectangular parallelepiped groove is provided above the countersunk hole of the support plate (1).

3. The steam generator eyelet threaded hole repairing device according to claim 2, characterized in that: The countersunk holes of the support plate (1) are connected to the small screw holes of the base plate (2) and the screw holes of the eyelet flange (4) in sequence through bolts; the size of the bolts is M24*3.

4. The steam generator eyelet threaded hole repairing device according to claim 3, characterized in that: The steam generator eyelet threaded hole repair device is also provided with a positioning tool (3); the positioning tool (3) is a rectangular parallelepiped structure, fixed on the rectangular parallelepiped groove of the support plate (1); the positioning tool (3) is provided with two screw holes, namely a screw hole C (8) and a screw hole D (9), and the position arrangement and size of the screw hole C (8) and the screw hole D (9) are respectively consistent with the screw hole A (6) and the screw hole B (7) on the bottom plate; the clearance between the bottom of the positioning tool (3) and the rectangular parallelepiped groove of the support plate (1) is 0.1-0.2 mm.

5. The steam generator eyelet threaded hole repairing device according to claim 4, characterized in that: The two screw holes of the positioning tool (3) are fixedly connected to the bottom plate (2) along the rectangular parallelepiped groove of the support plate (1) by screws; the size of the screws is M10.

6. A method for repairing a steam generator eyelet threaded hole using the steam generator eyelet threaded hole repairing device according to claim 5, comprising the following steps: 1) Clean the four screw holes of the eyelet flange (4) and seal the eyelet flange (4) with stainless steel tape to prevent foreign matter from entering the steam generator; 2) Select three small screw holes of the bottom plate (2) for positioning corresponding to the actual positions of the screw hole to be repaired and the other three screw holes, and align the bottom plate (2) on the eyelet flange (4); 3) Position the support plate (1) on the bottom plate (2) according to the actual positions of the three small screw holes of the bottom plate (2), connect the support plate (1), the bottom plate (2) and the eyelet flange (4) with three M24*3 bolts, and tighten the bolts; 4) Use a feeler gauge to check the gap between the surface of the eyelet flange (4) and the surface of the bottom plate (2), and between the support plate (1) and the bottom plate (2), and ensure the parallelism between the surface of the support plate (1) and the bottom plate (2) and the surface of the eyelet flange (4); 5) Select a magnetic drill (5) whose roundness and verticality meet the use requirements, and install a core rod with the same diameter as the screw hole to be repaired on its main shaft; continuously adjust the position of the magnetic drill until the core rod can smoothly pass through the screw hole to be repaired, which means that the magnetic drill is in the correct installation position, and adsorb the magnetic drill (5) on the support plate (1); 6) Remove the mandrel, place the positioning fixture (3) along the rectangular groove of the support plate (1) close to the bottom plate (2), connect the positioning fixture (3) to the bottom plate (2) with two M10 screws, and tighten the screws; 7) According to the hole enlarging operation, use the magnetic drill (5) to install the corresponding drill bit and perform the operation in stages. First, test drill on the positioning tool (3). After each stage of hole enlarging, check the position and verticality of the hole. 8) After the bottom hole is expanded, conduct a visual inspection, including the bottom hole depth and diameter; 9) Remove the repair tooling, visually inspect all screw holes, and perform go and no-go gauge checks; 10) Tap the repaired bottom hole, and use a ruler close to the tap during the tapping process to ensure the verticality of the tap; 11) Install the threaded bushing after tapping. After installation, check the verticality and position, and use the go and stop gauges to check; 12) The site is cleared after the work is completed and all materials are used up.

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