Online maintenance equipment suitable for nuclear power complex valve cavity neck bush

Abstract

The invention belongs to the technical field of nuclear power valve maintenance, and particularly relates to nuclear power complex valve cavity neck bush online maintenance equipment which comprises a positioning base, an X-direction moving module, a Y-direction moving module and a mechanical arm. The positioning base comprises a bottom plate and a side plate which are vertically connected; a to-be-maintained workpiece is installed on a side plate of the positioning base, the X-direction moving module is installed on a bottom plate of the positioning base, the Y-direction moving module is installed on the X-direction moving module, the mechanical arm is installed on the Y-direction moving module, the X-direction moving module is used for driving the mechanical arm to move in the X direction, and the Y-direction moving module is used for driving the mechanical arm to move in the Y direction. The Y-direction moving module is used for driving the mechanical arm to move in the Y direction, and the mechanical arm is used for axial cutting of the valve seat to be maintained and the lining and assembling of the lining. According to the invention, the problems of complexity and uncertainty of disassembly and assembly of the valve trim can be solved, and disassembly and assembly of the valve seat and the bushing can be smoothly completed.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear power valve maintenance, and in particular relates to an online maintenance device for a liner in a complex valve cavity of a nuclear power plant. Background Art

[0002] The regulator proportional spray valve 1 / 2RCP001 / 002VP is the most important nuclear primary pneumatic control valve in a circuit. When performing its dismantling PM (preventive maintenance) work, the valve must be dismantled, the valve internals removed, the worn parts replaced, and the valve reinstalled.

[0003] The valve trim of the proportional spray valve of the regulator is mainly composed of a V-ball valve core, a valve seat, a valve seat disc spring, a bushing, and a piston ring. The valve trim needs to be disassembled, replaced, and reinstalled during the maintenance process. During the disassembly of the valve seat, the bushing is worn at the joint with the valve seat piston ring due to the vibration of the valve trim; the piston ring has an open overlap, and the non-closed metal ring is stuck in the groove worn by the bushing due to its own tension, making it difficult to remove the valve seat, etc., and there are situations where it cannot be removed normally. In the recent overhauls of Fangjiashan, the problem of the valve seat being unable to be removed normally has occurred, and the difficulty of removing the valve seat has increased year by year. If the valve seat cannot be removed smoothly, the unit will face the replacement of the entire valve, and the unit will consume a lot of overhaul time costs, such as: welding process assessment, nuclear safety-related risk assessment time, etc.

[0004] The proportional spray valve of the voltage stabilizer has been operating at a small opening and small flow for a long time. Although the vibration and wear of the valve internal parts have been reduced after the operation mode optimization, the wear of the valve body bushing and the piston ring is still increasing. The valve body bushing is made of STL NO.6 and has an interference fit with the valve body. The wear of this component increases year by year, which will affect the minimum flow and flow stability of the valve, and seriously affect the safe and stable operation of the unit. If necessary, the bushing must be removed and cold installed (interference fit).

[0005] The valve body bushing is coaxial with the valve seat, while the valve body end cover flange opening has a 90° angle with the valve seat and bushing, and the internal space of the valve cavity is extremely small. In the past, the conventional method of removing the valve trim of the proportional spray valve was: after the valve was opened, the person manually reached into the valve cavity from the valve body end cover flange opening (only about 90mm in diameter), and used a screwdriver, a homemade two-jaw puller and other tools to pry and knock out the valve seat, piston ring, etc. Removing the valve seat required a lot of luck, and as the degree of bushing wear increased, the difficulty of removing the valve seat also increased year by year.

[0006] After investigation, there is no effective solution in the industry, nor is there any online maintenance equipment suitable for this working condition. Therefore, it is urgent to develop an online maintenance equipment for the liner in the complex valve cavity of nuclear power to solve the current problems. Summary of the invention

[0007] The purpose of the present invention is to provide an online maintenance device for the liner in the complex valve cavity of nuclear power, which can complete the removal and installation of the valve seat and the liner.

[0008] The technical solution to achieve the purpose of the present invention is:

[0009] An online maintenance device for a bushing in a complex valve cavity of a nuclear power plant, the device comprising: a positioning base, an X-direction moving module, a Y-direction moving module, and a mechanical arm; the positioning base comprises a bottom plate and a side plate connected vertically; a workpiece to be repaired is mounted on the side plate of the positioning base, the X-direction moving module is mounted on the bottom plate of the positioning base, the Y-direction moving module is mounted on the X-direction moving module, the mechanical arm is mounted on the Y-direction moving module, the X-direction moving module is used to drive the mechanical arm to move along the X-direction, the Y-direction moving module is used to drive the mechanical arm to move along the Y-direction, and the mechanical arm is used for axial cutting of a valve seat and bushing to be repaired and assembly of the bushing.

[0010] Furthermore, the positioning base side plate is provided with a positioning hole, the size of the positioning hole matches the valve body end cover flange, and is used to accommodate the valve body end cover flange. The positioning hole has a number of countersunk holes evenly distributed around the circumference, and the countersunk holes are concentric with the valve body threaded holes. The maintenance equipment is positioned at the position of the workpiece to be repaired by positioning bolts.

[0011] Further, the X-direction moving module includes: an X-direction translation guide rail, an X-direction servo drive motor, an X-direction motor positioning plate, an X-direction transmission belt, an X-direction bearing seat, an X-direction transmission screw, and a Y-direction moving module mounting base plate; the X-direction motor positioning plate, the X-direction translation guide rail, and the X-direction bearing seat are respectively installed on the positioning base base plate, the Y-direction moving module mounting base plate is slidably installed on the X-direction translation guide rail, the X-direction servo drive motor is installed on the X-direction motor positioning plate, the X-direction transmission screw is installed on the X-direction bearing seat, the X-direction servo drive motor is connected to the X-direction transmission screw through the X-direction transmission belt, and the X-direction transmission screw is transmission-connected to the Y-direction moving module mounting base plate; the Y-direction moving module is installed on the Y-direction moving module mounting base plate.

[0012] Furthermore, the Y-direction moving module includes: a Y-direction moving base plate, a Y-direction transmission belt, a Y-direction first bearing seat, a Y-direction translation guide rail, a Y-direction guide groove, a robot arm base mounting plate, a Y-direction transmission screw, a Y-direction servo drive motor, and a Y-direction second bearing seat; the Y-direction motor positioning plate, the Y-direction translation guide rail, the Y-direction first bearing seat, and the Y-direction second bearing seat are installed on the Y-direction moving base plate, the robot arm base mounting plate is slidably installed on the Y-direction translation guide rail through the Y-direction guide groove, the Y-direction servo drive motor is installed on the Y-direction motor positioning plate, both ends of the Y-direction transmission screw are installed on the Y-direction first bearing seat and the Y-direction second bearing seat, the Y-direction servo drive motor is connected to the Y-direction transmission screw through the Y-direction transmission belt, and the Y-direction transmission screw is transmission-connected to the robot arm base mounting plate; the robot arm is installed on the robot arm base mounting plate through the robot arm base.

[0013] Furthermore, the robotic arm includes an electric spark cutting robotic arm and a pneumatic clamper robotic arm. The electric spark cutting robotic arm is used to achieve axial cutting of the valve seat and the bushing, and the pneumatic clamper robotic arm is used to hold the bushing on the valve body of the voltage regulator spray valve or a replacement bushing to achieve liquid nitrogen cooling interference fitting of the bushing.

[0014] Furthermore, the electric spark cutting robot arm includes: an electric spark cutting robot arm, a polytetrafluoro insulating tool holder, a tool holder fixing bolt, an electric spark cutting tool head, and a metal rod; the polytetrafluoro insulating tool holder and the electric spark cutting robot arm are connected through a metal rod, the electric spark cutting tool head is installed on the polytetrafluoro insulating tool holder through the tool holder fixing bolt, and the electric spark cutting robot arm is installed on the robot arm base.

[0015] Furthermore, the electric spark cutting tool head is a graphite electrode, and the length of the graphite electrode is greater than the length of the bushing.

[0016] Furthermore, the EDM robot arm has a built-in cooling water circuit, which is connected to an external water pump. Through the cooling water circuit and the cooling water return groove at the side plate of the positioning base, circulating cooling water is continuously and evenly provided to the cutting area of ​​the EDM cutting head.

[0017] Furthermore, the pneumatic gripper robot arm includes: a robot arm connecting block, a square steel bridge, a cylinder, and a pneumatic gripper; the square steel bridge frame has built-in pneumatic and liquid nitrogen pipelines, a robot arm connecting block is installed at one end of the square steel bridge frame, and a pneumatic clamping device is installed at the other end, the pneumatic clamping device includes a cylinder and a pneumatic gripper, and the cylinder provides power for the pneumatic gripper.

[0018] Furthermore, the device also includes a control cabinet, which is electrically connected to the X-direction moving module, the Y-direction moving module, and the robotic arm to provide power and control for the X-direction moving module, the Y-direction moving module, and the robotic arm.

[0019] The beneficial technical effects of the present invention are:

[0020] 1. The present invention provides an online maintenance device for the liner in the complex valve cavity of nuclear power. By moving the module in the X direction and the module in the Y direction, the electric spark cutting head is accurately positioned to the position to be processed (valve seat, inner side of the liner), thus overcoming the mechanical processing problem caused by the 90° rotation angle of the valve.

[0021] 2. The present invention provides an online maintenance device for the bushing in a complex valve cavity of a nuclear power plant. The device cuts the valve seat or bushing by electric discharge of an electric spark cutting tool head, thereby solving the complexity and uncertainty of the disassembly and assembly of valve internals (mainly valve seats and bushings) faced by current on-site maintenance personnel.

[0022] 3. The present invention provides an online maintenance device for bushings in complex valve cavities of nuclear power plants. A graphite electrode sheet is customized at the front end of an electrospark robot arm, and the length of the graphite electrode sheet is slightly larger than the length of the bushing, so that a through cutting line can be machined in the axial direction of the bushing during electrospark machining. Since there is no reaction force during electrospark machining, only continuous cooling needs to be provided to complete the cutting of a fixed shape.

[0023] 4. The present invention provides an online maintenance device for the liner in the complex valve cavity of nuclear power. The servo drive motor in the X direction and the servo drive motor in the Y direction adopt PLC programming to control the servo motor, and the X direction translation guide rail and the Y direction translation guide rail adopt high-precision transmission guide rail, which effectively ensures the smooth movement of the robot arm.

[0024] 5. The present invention provides an online maintenance device for bushings in complex valve cavities of nuclear power plants, which can be installed with three processing robotic arms (electrical spark machining robotic arm, bushing cold installation robotic arm, valve body inner surface grinding robotic arm) to realize three different functions and achieve rapid switching of different functional modules on the same equipment platform. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is the valve body assembly drawing of the proportional spray valve of the pressure regulator;

[0026] Figure 2 This is a schematic diagram of the structure of an online maintenance device for linings in complex valve cavities in nuclear power plants provided by the present invention;

[0027] Figure 3 This is a schematic diagram of the structure of an X-direction moving module in an online maintenance device for a liner in a complex valve cavity of a nuclear power plant provided by the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of a Y-direction moving module in an online maintenance device for a liner in a complex valve cavity of a nuclear power plant provided by the present invention;

[0029] Figure 5 This is a schematic diagram of the structure of an electrospark cutting mechanical arm suitable for online maintenance equipment of linings in complex valve cavities of nuclear power plants provided by the present invention;

[0030] Figure 6 A schematic diagram of the structure of a pneumatic gripper mechanical arm suitable for online maintenance equipment of liner sleeves in complex valve cavities of nuclear power plants provided by the present invention;

[0031] Figure 7 This is a schematic diagram of a control cabinet in an online maintenance device for linings in complex valve cavities of nuclear power plants provided by the present invention.

[0032] In the figure:

[0033] 1-positioning base, 2-Y direction motion base plate, 3-Y direction transmission belt, 4-Y direction first bearing seat, 5-Y direction translation guide, 6-X direction translation guide, 7-X direction servo drive motor, 8-X direction motor positioning plate, 9-X direction transmission belt, 10-X direction bearing seat, 11-reserved hole, 12-EDM robot arm, 14-PTFE insulation tool holder, 15-tool holder fixing bolt, 16-EDM cutting tool head, 1 7-sink hole, 18-cooling water return groove, 19-Y direction guide groove, 20-wheel, 21-X direction transmission screw, 22-mechanical arm base mounting plate, 23-mechanical arm base, 24-Y direction transmission screw, 25-Y direction servo drive motor, 26-Y direction second bearing seat, 27-Y direction mobile module mounting base, 28-metal rod, 30-mechanical arm connection block, 31-square steel bridge, 32-cylinder, 33-pneumatic gripper;

[0034] 51-V ball valve core, 52-valve body end cover flange opening, 53-bushing, 54-valve seat, 55-piston ring, 56-valve seat disc spring, 57-valve body end cover flange;

[0035] 61-control cabinet, 62-touch screen, 63-roller, 64-spindle drive, 65-X-axis drive, 66-Z-axis drive, 67-PLC, 68-main switch, 69-switching power supply, 70-contactor, 71-relay, 72-wire bus, 73-handle. DETAILED DESCRIPTION

[0036] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0037] like Figure 1 As shown, the internal parts of the proportional spray valve of the pressure stabilizer include: a V-ball valve core 51, a valve body end cover flange opening 52, a bushing 53, a valve seat 54, a piston ring 55, a valve seat disc spring 56, and a valve body end cover flange 57.

[0038] like Figure 2As shown, the present invention provides an online maintenance device for a liner in a complex valve cavity of a nuclear power plant, comprising a positioning base 1, an X-direction moving module, a Y-direction moving module, and a mechanical arm.

[0039] The positioning base 1 includes a bottom plate and a side plate connected vertically, which are used for the construction and installation positioning of the entire equipment. The workpiece to be repaired is installed on the side plate of the positioning base 1, the X-direction moving module is installed on the bottom plate of the positioning base 1, the Y-direction moving module is installed on the X-direction moving module, and the mechanical arm is installed on the Y-direction moving module. The X-direction moving module is used to drive the mechanical arm to move along the X direction, and the Y-direction moving module is used to drive the mechanical arm to move along the Y direction. The mechanical arm is used for axial cutting of the valve seat and bushing to be repaired and assembly of the bushing.

[0040] In a specific embodiment, the positioning base 1 is composed of a bottom plate and a side plate vertically welded and provided with reinforcing ribs. The bottom plate is a hollow aluminum bottom plate, and the side plate is provided with a positioning hole. The size of the positioning hole matches the valve body end cover flange 57 and is used to accommodate the valve body end cover flange 57. The positioning hole has four countersunk holes 17 evenly distributed around the circumference. The countersunk holes 17 are concentric with the threaded holes of the valve body. The maintenance equipment is positioned at the position of the workpiece to be repaired by four positioning bolts.

[0041] In a specific embodiment, wheels 20 are installed under the bottom plate of the positioning base 1 to facilitate the movement of the maintenance equipment; and a cooling water return groove 18 is provided on the side plate of the positioning base 1 to facilitate the recycling of cooling water.

[0042] like Figure 3 As shown, the X-direction moving module includes: an X-direction translation guide rail 6, an X-direction servo drive motor 7, an X-direction motor positioning plate 8, an X-direction transmission belt 9, an X-direction bearing seat 10, an X-direction transmission screw 21, and a Y-direction moving module mounting base 27.

[0043] The X-direction motor positioning plate 8, the X-direction translation guide rail 6, and the X-direction bearing seat 10 are respectively installed on the bottom plate of the positioning base 1, the Y-direction moving module mounting bottom plate 27 is slidably mounted on the X-direction translation guide rail 6, the X-direction servo drive motor 7 is installed on the X-direction motor positioning plate 8, the X-direction transmission lead screw 21 is installed on the X-direction bearing seat 10, the X-direction servo drive motor 7 is connected to the X-direction transmission lead screw 21 through the X-direction transmission belt 9, and the X-direction transmission lead screw 21 is transmission-connected to the Y-direction moving module mounting bottom plate 27. The X-direction servo drive motor 7 drives the X-direction transmission lead screw 21 to rotate, and the rotation of the X-direction transmission lead screw 21 drives the Y-direction moving module mounting bottom plate 27 to perform linear motion in the X-direction (horizontal direction) along the X-direction translation guide rail 6, and can reciprocate.

[0044] The Y-direction moving module is fixedly mounted on the Y-direction moving module mounting base plate 27 by bolts, and moves along the X-direction together with the Y-direction moving module mounting base plate 27, driving the Y-direction transmission module and the robot arm to move together, thereby realizing the movement of the robot arm along the X-direction.

[0045] like Figure 4 As shown, the Y-direction moving module includes: a Y-direction moving base plate 2, a Y-direction transmission belt 3, a Y-direction first bearing seat 4, a Y-direction translation guide rail 5, a Y-direction guide groove 19, a robot arm base mounting plate 22, a Y-direction transmission screw 24, a Y-direction servo drive motor 25, and a Y-direction second bearing seat 26.

[0046] The Y-direction motor positioning plate, the Y-direction translation guide rail 5, the Y-direction first bearing seat 4, and the Y-direction second bearing seat 26 are installed on the Y-direction motion bottom plate 2, the robot base mounting plate 22 is slidably mounted on the Y-direction translation guide rail 5 through the Y-direction guide groove 19, the Y-direction servo drive motor 25 is installed on the Y-direction motor positioning plate, the two ends of the Y-direction transmission lead screw 24 are installed on the Y-direction first bearing seat 4 and the Y-direction second bearing seat 26, the Y-direction servo drive motor 25 is connected to the Y-direction transmission lead screw 24 through the Y-direction transmission belt 3, and the Y-direction transmission lead screw 24 is transmission-connected to the robot base mounting plate 22. The main shaft of the Y-direction servo drive motor 25 drives the Y-direction transmission belt 3 to move, the Y-direction transmission belt 3 drives the Y-direction transmission lead screw 24 to rotate, and the rotation of the Y-direction transmission lead screw 24 drives the robot base mounting plate 22 to perform linear motion in the Y direction (vertical direction) along the Y-direction translation guide rail 5.

[0047] In a specific embodiment, the first Y-direction bearing seat 4 and the second Y-direction bearing seat 26 are respectively connected and fixed to the Y-direction moving base plate 2 by connecting bolts.

[0048] In a specific implementation, the X-direction servo drive motor 7 and the Y-direction servo drive motor 25 adopt PLC programming control servo motors, and the X-direction translation guide rail 6 and the Y-direction translation guide rail 5 adopt high-precision transmission guide rails.

[0049] The robot base 23 is fixedly mounted on the robot base mounting plate 22 by bolts, and the robot arm is fixedly mounted on the robot base 23 by bolts. The robot arm moves along the Y direction together with the robot base 23 to realize the Y direction movement of the robot arm.

[0050] The robot arm includes an electric spark cutting robot arm and a pneumatic gripper robot arm. The electric spark cutting robot arm is used to realize axial cutting of the valve seat and the bushing. The pneumatic gripper robot arm is used to hold the bushing on the valve body of the stabilizer spray valve or the bushing for replacement to realize liquid nitrogen cooling interference fitting of the bushing.

[0051] like Figure 5 As shown, the electric spark cutting robot arm includes: an electric spark cutting robot arm 12, a polytetrafluoroethylene insulating tool holder 14, a tool holder fixing bolt 15, an electric spark cutting tool head 16, and a metal rod 28.

[0052] The polytetrafluoro insulating tool holder 14 is connected to the electric spark robot arm 12 through a metal rod 28 , and the electric spark cutting tool head 16 is installed on the polytetrafluoro insulating tool holder 14 through a tool holder fixing bolt 15 .

[0053] The EDM robot arm 12 has a built-in cooling water circuit, which is connected to an external water pump. Through the cooling water circuit and the cooling water return tank 18 at the side plate of the positioning base 1, circulating cooling water is continuously and evenly provided to the cutting area of ​​the EDM cutting head 16.

[0054] In a specific embodiment, the electric spark cutting tool head 16 is a graphite electrode, and the length of the graphite electrode is slightly greater than the length of the bushing.

[0055] In another specific embodiment, the electric spark cutting tool head 16 can be replaced with other different materials.

[0056] The electric spark robot arm 12 is fixedly mounted on the reserved hole 11 of the robot arm base 23 by means of bolts.

[0057] Electrical Discharge Machining (EDM) is a processing method that uses continuous or intermittent electric sparks (discharge) to erode metal materials. In this process, the high voltage between the workpiece (valve seat, bushing) and the electrode of the electric spark cutting head generates high-temperature sparks in the tiny gap, which can melt and erode the metal material, thereby breaking the valve seat and bushing.

[0058] During the EDM cutting process, the evaporated or melted material needs to be quickly removed to keep the gap between the electrode and the workpiece constant. Cooling water can effectively take away this heat, control the temperature of the workpiece and the electrode, and avoid overheating to cause structural changes or damage to the material. Cooling water not only provides cooling and reduces the heat affected zone (HAZ) after processing, but also can flush metal particles and other residues generated during the processing away from the processing area, keep the gap between the electrode and the workpiece clean, and avoid short circuits and unstable discharge. The cooling water is powered by an external water pump, and continuously and evenly provides circulating cooling water to the cutting area through the cooling water circuit built into the EDM cutting robot and the cooling water return tank 18 at the side plate of the positioning base 1.

[0059] like Figure 6 As shown, the pneumatic gripper robot arm includes: a robot arm connecting block 30, a square steel bridge 31, a cylinder 32, and a pneumatic gripper 33.

[0060] The square steel bridge 31 has pneumatic and liquid nitrogen pipelines built in. A robotic arm connection block 30 is installed at one end of the square steel bridge 31 and a pneumatic clamping device is installed at the other end. The pneumatic clamping device includes a cylinder 32 and a pneumatic gripper 33. The cylinder 32 provides power for the pneumatic gripper 33.

[0061] The square steel bridge 31 of the pneumatic gripper mechanical arm is fixedly mounted on the reserved hole 11 of the mechanical arm base 23 through the mechanical arm connecting block 30 and bolts.

[0062] The mechanical arm also includes a valve body inner surface grinding mechanical arm, which is used for grinding the valve body inner surface.

[0063] The present invention provides an online maintenance device for a liner sleeve in a complex nuclear power valve cavity, which also includes an endoscope component. The endoscope component extends into the interior of the valve body and is used to observe the positioning and cutting operations of the cutter head.

[0064] The present invention provides an online maintenance device for the liner of a complex valve cavity of a nuclear power plant, which also includes a control cabinet, such as Figure 7 As shown, the control cabinet is electrically connected to the X-direction moving module, the Y-direction moving module, and the robotic arm, and provides power and control for the X-direction moving module, the Y-direction moving module, and the robotic arm.

[0065] In a specific embodiment, the control cabinet is electrically connected to the X-direction servo drive motor 7 and the Y-direction servo drive motor 25, and is used to control the X-direction servo drive motor 7 and the Y-direction servo drive motor 25 to move the electric spark cutting head 16 to the predetermined position of the valve seat and the inner side of the bushing, and the positioning of the electric spark cutting head 16 is observed through a visualization device. The control cabinet is electrically connected to the electric spark cutting head 16, and is used to provide power and control for the electric spark cutting head 16. The control cabinet is electrically connected to the cylinder 32, and is used to control the cylinder 32.

[0066] The control cabinet can provide the electric spark cutting tool head 16 with pulse currents of multiple frequency bands and power of multiple gears.

[0067] The multiple frequency bands of pulse current and multiple gears of power of the EDM cutting head 16 provide a rich selection of operating parameters for the maintenance equipment. The cutting parameters of the EDM cutting head 16 can be flexibly adjusted according to specific conditions and requirements to achieve precise cutting of the valve body. This can meet the needs of different maintenance scenarios and enhance the flexibility and adaptability of operation.

[0068] The present invention is described in detail above with reference to the accompanying drawings and embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the field without departing from the purpose of the present invention. The contents not described in detail in the present invention can adopt the existing technology.

Claims

1. An online maintenance device for the lining of complex valve cavities in nuclear power plants, characterized in that: The device comprises: a positioning base (1), an X-direction moving module, a Y-direction moving module, and a mechanical arm; the positioning base (1) comprises a bottom plate and a side plate connected vertically; the workpiece to be repaired is mounted on the side plate of the positioning base (1), the X-direction moving module is mounted on the bottom plate of the positioning base (1), the Y-direction moving module is mounted on the X-direction moving module, and the mechanical arm is mounted on the Y-direction moving module; the X-direction moving module is used to drive the mechanical arm to move along the X-direction, the Y-direction moving module is used to drive the mechanical arm to move along the Y-direction, and the mechanical arm is used to axially cut the valve seat and bushing to be repaired and assemble the bushing.

2. According to claim 1, the online maintenance equipment for the liner of complex valve cavity of nuclear power is characterized in that: The side plate of the positioning base (1) is provided with a positioning hole, the size of which matches the valve body end cover flange (57) and is used to accommodate the valve body end cover flange (57). A plurality of countersunk holes (17) are evenly distributed around the positioning hole, and the countersunk holes (17) are concentric with the valve body threaded holes. The maintenance equipment is positioned at the position of the workpiece to be repaired by means of positioning bolts.

3. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 1 is characterized in that: The X-direction moving module comprises: an X-direction translation guide rail (6), an X-direction servo drive motor (7), an X-direction motor positioning plate (8), an X-direction transmission belt (9), an X-direction bearing seat (10), an X-direction transmission lead screw (21), and a Y-direction moving module mounting base plate (27); the X-direction motor positioning plate (8), the X-direction translation guide rail (6), and the X-direction bearing seat (10) are respectively mounted on the bottom plate of the positioning base (1); the Y-direction moving module mounting base plate (27) is slidably mounted on the X-direction translation guide rail (6); the X-direction servo drive motor (7) is mounted on the X-direction motor positioning plate (8); the X-direction transmission lead screw (21) is mounted on the X-direction bearing seat (10); the X-direction servo drive motor (7) is connected to the X-direction transmission lead screw (21) via the X-direction transmission belt (9); the X-direction transmission lead screw (21) is transmission-connected to the Y-direction moving module mounting base plate (27); and the Y-direction moving module is mounted on the Y-direction moving module mounting base plate (27).

4. The online maintenance equipment for the liner of complex valve cavity in nuclear power according to claim 1 is characterized in that: The Y-direction moving module comprises: a Y-direction moving base plate (2), a Y-direction transmission belt (3), a Y-direction first bearing seat (4), a Y-direction translation guide rail (5), a Y-direction guide groove (19), a robot arm base mounting plate (22), a Y-direction transmission lead screw (24), a Y-direction servo drive motor (25), and a Y-direction second bearing seat (26); the Y-direction motor positioning plate, the Y-direction translation guide rail (5), the Y-direction first bearing seat (4), and the Y-direction second bearing seat (26) are mounted on the Y-direction moving base plate (2); the robot arm base mounting plate (22) is connected to the Y-direction servo drive motor (24) by the Y-direction servo drive motor (25), and the Y-direction second bearing seat (26) is connected to the Y-direction servo drive motor (25). The Y-direction guide groove (19) is slidably mounted on the Y-direction translation guide rail (5); the Y-direction servo drive motor (25) is mounted on the Y-direction motor positioning plate; both ends of the Y-direction transmission lead screw (24) are mounted on the Y-direction first bearing seat (4) and the Y-direction second bearing seat (26); the Y-direction servo drive motor (25) and the Y-direction transmission lead screw (24) are connected via a Y-direction transmission belt (3); the Y-direction transmission lead screw (24) is transmission-connected to the robot arm base mounting plate (22); and the robot arm is mounted on the robot arm base mounting plate (22) via the robot arm base (23).

5. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 1 is characterized in that: The mechanical arm includes an electric spark cutting mechanical arm and a pneumatic clamping mechanical arm. The electric spark cutting mechanical arm is used to realize axial cutting of the valve seat and the bushing. The pneumatic clamping mechanical arm is used to hold the bushing on the valve body of the stabilizer spray valve or the bushing for replacement to realize liquid nitrogen cooling interference fitting of the bushing.

6. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 5 is characterized in that: The electric spark cutting mechanical arm comprises: an electric spark mechanical arm (12), a polytetrafluoro insulating tool holder (14), a tool holder fixing bolt (15), an electric spark cutting tool head (16), and a metal rod (28); the polytetrafluoro insulating tool holder (14) and the electric spark mechanical arm (12) are connected via the metal rod (28), the electric spark cutting tool head (16) is mounted on the polytetrafluoro insulating tool holder (14) via the tool holder fixing bolt (15), and the electric spark mechanical arm (12) is mounted on a mechanical arm base (23).

7. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 6 is characterized in that: The electric spark cutting tool head (16) is a graphite electrode, and the length of the graphite electrode is greater than the length of the bushing.

8. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 6 is characterized in that: The electric spark robot arm (12) has a built-in cooling water circuit, which is connected to an external water pump. Circulating cooling water is continuously and evenly provided to the cutting area of ​​the electric spark cutting head (16) through the cooling water circuit and the cooling water return groove (18) at the side plate of the positioning base (1).

9. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 5 is characterized in that: The pneumatic gripper mechanical arm comprises: a mechanical arm connecting block (30), a square steel bridge (31), a cylinder (32), and a pneumatic gripper (33); the square steel bridge (31) is internally provided with pneumatic and liquid nitrogen pipelines; one end of the square steel bridge (31) is provided with the mechanical arm connecting block (30) and the other end is provided with a pneumatic gripper; the pneumatic gripper comprises a cylinder (32) and a pneumatic gripper (33); the cylinder (32) provides power for the pneumatic gripper (33).

10. The online maintenance equipment for the liner in complex valve cavity of nuclear power according to claim 1 is characterized in that: The device also includes a control cabinet, which is electrically connected to the X-direction moving module, the Y-direction moving module, and the mechanical arm to provide power and control for the X-direction moving module, the Y-direction moving module, and the mechanical arm.

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