Lower Seal Weld Cutting Device and Method for Control Rod Drive Mechanism

Abstract

The present invention discloses a cutting device and method for the lower sealed weld of a control rod drive mechanism. The cutting device for the lower sealed weld of the control rod drive mechanism includes a positioning mechanism, a clamping mechanism, and a cutting mechanism. The positioning mechanism is used to be positioned on the outer periphery of the lower part of the pressure-resistant shell. The clamping mechanism is connected above the positioning mechanism and is used to clamp the outer periphery of the pressure-resistant shell. The cutting mechanism is connected below the positioning mechanism and is used to be fixed on the outer periphery of the lower part of the pressure-resistant shell. The Ω sealed weld between the lower part of the pressure-resistant shell and the pipe seat is cut by aligning with a cutter assembly. In the present invention, the clamping mechanism, the positioning mechanism, and the cutting mechanism are sequentially connected up and down to form a compact overall device, which can be hoisted to the outer peripheries of the lower part of the pressure-resistant shell and the pipe seat to cut the sealed weld between the lower part of the pressure-resistant shell and the pipe seat, realizing automatic operation without manual approach to the highly radioactive pressure-resistant shell, and having high working efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of processing of nuclear reactor control rod drive mechanisms, and particularly relates to a cutting device and method for the lower seal weld of a control rod drive mechanism. Background Art

[0002] In nuclear power plants, as the service life of the unit increases, the number of worn thermal sleeves also gradually increases. Therefore, the need to replace the thermal sleeves inside the reactor is imminent. Referring to Figure 1 , on the reactor pressure vessel head, the thermal sleeve is located inside the control rod drive mechanism. The first step to replace the thermal sleeve must be to cut the Ω seal weld between the lower part of the pressure-resistant shell and the tube seat in the control rod drive mechanism.

[0003] Currently, there is no dedicated equipment for cutting the Ω seal weld between the lower part of the pressure-resistant shell and the tube seat. It is necessary to manually cooperate with a variety of devices for operation, which poses a high risk of radioactive radiation, and the limited surrounding space also affects the operation efficiency and quality. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a cutting device and method for the lower seal weld of a control rod drive mechanism that does not require manual operation close by and improves the cutting efficiency.

[0005] The technical solution adopted by the present invention to solve its technical problems is: to provide a cutting device for the lower seal weld of a control rod drive mechanism, which is installed on the outer sides of the lower part of the pressure-resistant shell and the tube seat of the control rod drive mechanism; the cutting device for the lower seal weld of the control rod drive mechanism includes a positioning mechanism, a clamping mechanism, and a cutting mechanism;

[0006] The positioning mechanism is used to be positioned on the outer periphery of the lower part of the pressure-resistant shell, and the clamping mechanism is connected above the positioning mechanism and is used to clamp on the outer periphery of the pressure-resistant shell;

[0007] The cutting mechanism is connected below the positioning mechanism and is used to be fixed on the outer periphery of the lower part of the pressure-resistant shell, and the Ω seal weld between the lower part of the pressure-resistant shell and the tube seat is cut by aligning the cutter assembly.

[0008] Preferably, the positioning mechanism includes a main shaft sleeved on the outer periphery of the lower part of the pressure-resistant shell, at least one set of pressing components arranged on the main shaft, and a turning component arranged on the main shaft;

[0009] The pressing assembly includes a first cylinder with a push rod facing downward, a first cylinder fork connected to the push rod of the first cylinder, and a pressing rod with its first end passing through the first cylinder fork. The opposite second end of the pressing rod passes through the side wall of the main shaft near the pressure-resistant shell; the first cylinder operates and drives the pressing rod to rotate up and down through the first cylinder fork, driving the second end of the pressing rod to fit against the lower step surface of the pressure-resistant shell;

[0010] The turning assembly includes a second cylinder with a horizontally extending push rod, a second cylinder fork rotatably connected to the push rod of the second cylinder, a first turning rod and a first turning block connected below the second cylinder fork; a first through channel running through the upper and lower parts is provided in the side wall of the main shaft, the first turning rod is arranged in the first through channel, and the first turning block is arranged at the lower end of the first turning rod and located outside the lower end opening of the first through channel; the second cylinder operates and drives the first turning rod to rotate through the second cylinder fork, driving the first turning block to rotate out and abut against the bottom end surface of the lower part of the pressure-resistant shell or retract away from the bottom end surface.

[0011] Preferably, the pressing assembly further includes a first cylinder seat;

[0012] The first cylinder is fixed to the outer periphery of the upper end of the main shaft through the first cylinder seat;

[0013] The first cylinder fork is a vertically arranged rectangular frame body, and a first pin shaft is provided at the inner bottom of the rectangular frame body. The first pin shaft contacts the lower surface of the first end of the pressing rod; the second end of the pressing rod passes through the vertical plate of the first cylinder seat and is rotatably connected to the vertical plate through a rotating shaft.

[0014] Preferably, the turning assembly further includes a toothed ring, a turning gear, a pressing cap, a connecting rod, and at least one second turning rod;

[0015] The toothed ring is rotatably sleeved on the upper end of the main shaft, the turning gear is arranged at the upper end of the first turning rod and meshes with the toothed ring, the pressing cap is arranged on the turning gear and is limited above the toothed ring to prevent the toothed ring from moving up and down on the main shaft; the connecting rod is rotatably connected between the pressing cap and the second cylinder fork;

[0016] A second through channel running through the upper and lower parts is provided in the side wall of the main shaft, and the second turning rod is arranged in the second through channel; a linkage gear is provided at the upper end of the second turning rod and meshes with the toothed ring, and a second turning block is provided at the lower end of the second turning rod;

[0017] The second cylinder operates and drives the toothed ring to rotate through the second cylinder fork, connecting rod, and turning gear. The rotation of the toothed ring drives the second lever to rotate through the linkage gear, and further drives the second block to rotate out and abut against the bottom end face of the lower part of the pressure-resistant shell or retract and leave the bottom end face.

[0018] Preferably, the clamping mechanism includes a support cylinder sleeved on the outer periphery of the pressure-resistant shell and connected above the main shaft, a suspension flange connected above the support cylinder and connected to the hoisting assembly, a clamping cylinder sleeved on the outer periphery of the support cylinder, a third cylinder connected to the clamping cylinder and the support cylinder, and at least one set of clamping execution components;

[0019] The clamping execution components include a clamping plate extending along the axial direction of the main shaft and arranged inside the main shaft, a first clamping block and a second clamping block respectively arranged on the main shaft corresponding to the upper and lower ends of the clamping plate; the top of the clamping plate is connected to the clamping cylinder through a hinge assembly, a first guiding inclined surface cooperating with the first clamping block is arranged at the upper end of the clamping plate, and a second guiding inclined surface cooperating with the second clamping block is arranged at the lower end of the clamping plate;

[0020] The third cylinder operates to drive the clamping cylinder to move upward relative to the support cylinder, driving the clamping plate to move upward. The clamping plate converges towards the axis of the pressure-resistant shell through the inclined surface cooperation with the first clamping block and the second clamping block, so as to clamp on the pressure-resistant shell.

[0021] Preferably, the hinge assembly includes a first hinge seat, a second hinge seat, and a connecting piece;

[0022] The first hinge seat is fixed on the clamping cylinder, the second hinge seat is fixed on the top of the clamping plate, and the connecting piece is rotatably connected between the first hinge seat and the second hinge seat.

[0023] Preferably, the clamping execution components further include at least two sets of guiding screws;

[0024] Guiding grooves are respectively arranged on the opposite two side surfaces of the upper end and / or the lower end of the clamping plate, and the extending direction of the guiding grooves is parallel to the up and down movement direction of the clamping plate; the guiding screws are arranged in the main shaft, and one end faces and cooperates with the guiding grooves.

[0025] Preferably, the clamping mechanism further includes an anti-falling rod and an anti-falling block;

[0026] The anti-falling rod is arranged between the clamping cylinder, the support cylinder, and the suspension flange, and the anti-falling block is fitted at the lower end of the anti-falling rod and fixed on the clamping cylinder through a locking member.

[0027] Preferably, the cutting mechanism includes an inner shell sleeved on the main shaft and rotatable relative to the main shaft, an outer shell sleeved outside the inner shell and fixedly relative to the main shaft, a rotary gear sleeved on the main shaft and connected to one end of the inner shell, a first differential gear sleeved outside the inner shell, a driving element fixed on the outer shell, a transmission shaft fixed on the outer shell and arranged in parallel at an interval from the shaft end of the driving element, a transition gear and a second differential gear coaxially arranged on the transmission shaft, a cutting disc, and at least one cutter assembly;

[0028] A driving gear is provided at the shaft end of the driving element. The rotary gear meshes with the driving gear and the transition gear respectively, and the second differential gear meshes with the first differential gear;

[0029] The cutting disc is sleeved on the outer periphery of the main shaft and fixed on the rotary gear. The cutter assembly is arranged on the cutting disc and aligned with the Ω seal weld between the lower part of the pressure-resistant shell and the pipe seat;

[0030] A cam track groove is provided on the first differential gear. The cutter assembly is fitted on the cam track groove of the first differential gear through a positioning shaft;

[0031] After the driving element acts, the driving gear drives the rotary gear to rotate at a first angular velocity. At the same time, the transition gear and the second differential gear also rotate at the first angular velocity. The second differential gear drives the first differential gear to rotate at a second angular velocity. The rotation of the first differential gear drives the positioning shaft to move along the cam track groove, and then drives the cutter assembly to move relative to the cutting disc in the direction of approaching and departing from the Ω seal weld, so as to cut the Ω seal weld.

[0032] Preferably, the cutting mechanism further includes a bearing assembly arranged between the inner shell and the outer shell;

[0033] The upper shaft shoulder of the inner shell abuts against the upper end face of the bearing assembly, and a limiting ring is provided at the lower part of the inner shell to be restricted at the lower end of the bearing assembly.

[0034] Preferably, the cutter assembly includes a tool holder and a cutter mounted on the tool holder;

[0035] A chute extending radially along the cutting disc is provided on the cutting disc. A guide rail is provided on the chute. The tool holder is fitted on the guide rail and can move back and forth along the guide rail;

[0036] The bottom surface of the chute and the rotary gear are provided with relatively communicating moving guide grooves. One end of the positioning shaft is fixed on the tool holder, and the other end passes through the moving guide grooves and is respectively fitted in the cam track groove of the first differential gear.

[0037] Preferably, the cutting mechanism further includes a box body disposed on the outer side of the housing; the driving element and the transmission shaft are respectively disposed in the box body.

[0038] Preferably, the cutting device for the lower sealing weld of the control rod drive mechanism further includes a material receiving mechanism disposed on the outer periphery of the tube seat for collecting the debris falling from the cutting.

[0039] Preferably, the material receiving mechanism includes an outer cover body disposed on the outer periphery of the tube seat, a plurality of sets of expanding and contracting components disposed in the outer cover body, and a fireproof cloth;

[0040] The plurality of sets of expanding and contracting components are arranged at intervals along the circumferential direction of the tube seat on the inner bottom surface of the outer cover body, and can be rotatably clamped on the tube seat or expanded away from the tube seat relative to the outer cover body;

[0041] The fireproof cloth is disposed on the inner bottom surface of the outer cover body and covers the expanding and contracting components, defining a collection space located between the outer cover body and the fireproof cloth.

[0042] Preferably, a protruding support ring column is provided in the central through hole of the outer cover body, and an expandable and contractible ring sleeved on the outer periphery of the support ring column and movable is provided on the inner bottom surface of the outer cover body;

[0043] The plurality of sets of expanding and contracting components are arranged at intervals along the circumferential direction of the support ring column and are connected to the expandable and contractible ring and the support ring column;

[0044] The material receiving mechanism further includes a driving unit, and the driving unit is connected to the expandable and contractible ring to drive the expandable and contractible ring to move up and down, driving the expanding and contracting components to rotatably clamp on the tube seat or expand away from the tube seat relative to the support ring column and the expandable and contractible ring.

[0045] Preferably, the expanding and contracting component includes an expanding and contracting rod, a first connecting seat, a second connecting seat and a connecting member;

[0046] The first connecting seat is disposed on the support ring column, and the second connecting seat is disposed on the expandable and contractible ring;

[0047] The expanding and contracting rod includes an expanding and contracting rod body and a hinged section angularly connected to the end of the expanding and contracting rod body; one end of the hinged section connected to the expanding and contracting rod body is rotatably connected to the first connecting seat, and the other end of the hinged section away from the expanding and contracting rod body is rotatably connected to the second connecting seat through the connecting member.

[0048] Preferably, the outer cover body includes a bottom plate sleeved on the outer periphery of the tube seat, a suspension bracket vertically connected to the periphery of the bottom plate, a surrounding plate surrounding the suspension bracket on all sides, and a support leg connected to the lower end of the bottom plate and used for supporting on the top cover of the pressure vessel; the top of the suspension bracket is fixedly connected to the outer periphery of the positioning mechanism.

[0049] The present invention also provides a method for cutting the lower sealed weld of a control rod drive mechanism. Using the cutting device for the lower sealed weld of the control rod drive mechanism described in any one of the above, the method for cutting the lower sealed weld of the control rod drive mechanism includes the following steps:

[0050] S1. Lift the cutting device for the lower sealed weld of the control rod drive mechanism through the hoisting assembly, and pass it through the pressure-resistant shell of the control rod drive mechanism until reaching the lower position of the pressure-resistant shell connecting pipe seat;

[0051] S2. Through the cooperation between the positioning mechanism of the cutting device for the lower sealed weld of the control rod drive mechanism and the lower part of the pressure-resistant shell, position the cutting device for the lower sealed weld of the control rod drive mechanism on the outer periphery of the pressure-resistant shell. At the same time, the cutting mechanism of the cutting device for the lower sealed weld of the control rod drive mechanism corresponds to the outside of the Ω sealed weld between the lower part of the pressure-resistant shell and the pipe seat;

[0052] S3. The clamping mechanism of the cutting device for the lower sealed weld of the control rod drive mechanism acts to clamp on the outer periphery of the pressure-resistant shell;

[0053] S4. The cutting mechanism acts, and the Ω sealed weld is cut by its cutter assembly.

[0054] Preferably, before step S4, it further includes:

[0055] The material receiving mechanism of the cutting device for the lower sealed weld of the control rod drive mechanism converges and clamps the pipe seat;

[0056] In step S4, the debris generated during the cutting of the Ω sealed weld falls into the material receiving mechanism.

[0057] Preferably, the method for cutting the lower sealed weld of the control rod drive mechanism further includes the following steps:

[0058] S5. After the cutting is completed, the cutting mechanism acts to retract the cutter assembly to the initial position, the clamping mechanism releases the clamping of the pressure-resistant shell, and the positioning mechanism releases the positioning action;

[0059] S6. Lift the cutting device for the lower sealed weld of the control rod drive mechanism through the hoisting assembly to disengage it from the pressure-resistant shell.

[0060] The beneficial effects of the present invention: The compact overall device is formed by connecting the clamping mechanism, the positioning mechanism, and the cutting mechanism in sequence from top to bottom. It can be hoisted to the lower part of the pressure-resistant shell and the outer periphery of the pipe seat to cut the sealed weld between the lower part of the pressure-resistant shell and the pipe seat, realizing automatic operation without the need for manual approach to the highly radioactive pressure-resistant shell; with high working efficiency, greatly shortening the overhaul and maintenance time of the nuclear reactor unit; solving the problem of automatically completing positioning in an environment where manual access and intervention are impossible, with high positioning accuracy and simple operation.

[0061] The present invention can be adapted to operations in narrow spaces and is applicable to all pressure-resistant shells with dense distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] The present invention will be further described below in conjunction with the drawings and embodiments. In the drawings:

[0063] Figure 1 is a schematic structural diagram of the cooperation between the control rod drive mechanism and the pipe seat on the top cover of the pressure vessel;

[0064] Figure 2 is a schematic structural diagram of the lower seal weld cutting device (partial section) of the control rod drive mechanism in an embodiment of the present invention on the top cover of the pressure vessel;

[0065] Figure 3 is a schematic structural diagram of the lower seal weld cutting device of the control rod drive mechanism in an embodiment of the present invention on the outside of the pressure-resistant shell and the pipe seat;

[0066] Figure 4 is Figure 3 a schematic structural diagram of the positioning mechanism in the lower seal weld cutting device of the control rod drive mechanism shown;

[0067] Figure 5 is Figure 4 a schematic longitudinal sectional structural diagram of the positioning mechanism shown;

[0068] Figure 6 is Figure 4 a schematic structural diagram of the dialing component and the toothed ring in the positioning mechanism shown;

[0069] Figure 7 is Figure 4 a schematic diagram of the state change of the positioning mechanism on the outside of the pressure-resistant shell;

[0070] Figure 8 is Figure 3 a schematic structural diagram of the clamping mechanism in the lower seal weld cutting device of the control rod drive mechanism shown;

[0071] Figure 9 is Figure 8 a schematic longitudinal sectional structural diagram of the clamping mechanism shown;

[0072] Figure 10 is Figure 9 a schematic structural diagram of the clamping plate in the clamping mechanism shown;

[0073] Figure 11 is Figure 9 a schematic sectional structural diagram of the A-A line in;

[0074] Figure 12 isFigure 8 Schematic diagram of the state change of the clamping and releasing of the shown clamping mechanism on the outer side of the pressure-resistant shell;

[0075] Figure 13 is Figure 3 Schematic diagram of the structure of the cutting mechanism in the cutting device for the lower sealing weld of the control rod drive mechanism shown;

[0076] Figure 14 is Figure 13 Schematic diagram of the longitudinal sectional structure of the cutting mechanism shown;

[0077] Figure 15 is Figure 13 Schematic diagram of the bottom structure of the cutting mechanism shown;

[0078] Figure 16 is Figure 15 Schematic diagram of the structure of the first differential gear in;

[0079] Figure 17 is Figure 15 Schematic diagram of the structure of the cutting disc in;

[0080] Figure 18 is Figure 15 Schematic diagram of the structure of the rotating gear in;

[0081] Figure 19 is Figure 3 Schematic diagram of the structure of the material receiving mechanism (removing part of the enclosing plate and fireproof cloth) in the cutting device for the lower sealing weld of the control rod drive mechanism shown in the clamped state;

[0082] Figure 20 is Figure 19 Schematic diagram of the structure of the material receiving mechanism in the expanded state shown;

[0083] Figure 21 is Figure 19 Schematic diagram of the structure of the expansion and contraction rod in the material receiving mechanism shown. Detailed implementation manners

[0084] For a clearer understanding of the technical features, objectives, and effects of the present invention, the detailed implementation manners of the present invention will now be described in detail with reference to the accompanying drawings.

[0085] As Figure 2 shown, the cutting device 100 for the lower sealing weld of the control rod drive mechanism of the present invention is mainly used to be hoisted onto the top cover 200 of the pressure vessel and installed on the lower part of the pressure-resistant shell 300 of the control rod drive mechanism and the outer side of the pipe seat 400, so as to cut the Ω sealing weld between the lower part of the pressure-resistant shell 300 and the pipe seat 400, and the cutting device 100 for the lower sealing weld of the control rod drive mechanism can be hoisted away after the cutting is completed.

[0086] Combined withFigure 2 and Figure 3 For the cutting device 100 of the lower sealing weld of the control rod drive mechanism according to an embodiment of the present invention, it may include a positioning mechanism 10, a clamping mechanism 20, a cutting mechanism 30, and a material receiving mechanism 40. Along the hoisting direction of the entire device, the clamping mechanism 20, the positioning mechanism 10, the cutting mechanism 30, and the material receiving mechanism 40 are connected in sequence from top to bottom, forming a compact whole, which is convenient for hoisting to carry out cutting work and hoisting away.

[0087] The disassembly and assembly of the cutting device 100 of the lower sealing weld of the control rod drive mechanism on the pressure-resistant shell 300 are realized through a hoisting assembly 500.

[0088] On the top cover of the pressure vessel, the lower part of the pressure-resistant shell 300 of the control rod drive mechanism is connected to the tube seat 400, and the sealing connection is realized through the Ω sealing weld formed by welding. Therefore, the positioning mechanism 10 is used to be positioned on the outer periphery of the lower part of the pressure-resistant shell 300, so as to realize the positioning of the entire cutting device of the lower sealing weld of the control rod drive mechanism outside the pressure-resistant shell 300. The clamping mechanism 20 is connected above the positioning mechanism 10 and is used to clamp the outer periphery of the pressure-resistant shell 300 to realize the clamping and fixing of the entire device on the pressure-resistant shell 300. The cutting mechanism 30 is connected below the positioning mechanism 10 and is used to be fixed on the outer periphery of the lower part of the pressure-resistant shell 300. Through its cutter assembly 310 (refer to Figure 15 shown), it aligns and cuts the Ω sealing weld between the lower part of the pressure-resistant shell 300 and the tube seat 400. The material receiving mechanism 40 is connected below the cutting mechanism 30 to collect the debris generated by cutting.

[0089] Specifically, as shown in Figures 3 - 6 , the positioning mechanism 10 may include a main shaft 11, a pressing assembly 12, and a turning assembly 13. The main shaft 11 is a hollow shaft body that can be sleeved on the outer periphery of the lower part of the pressure-resistant shell 300; the pressing assembly 12 and the turning assembly 13 are respectively arranged on the main shaft 11, and the two respectively act to realize the positioning of the positioning mechanism 10 on the outer periphery of the pressure-resistant shell 200.

[0090] Among them, the pressing assembly 12 has at least one group, and when there are two or more groups, they are arranged at intervals along the circumferential direction of the main shaft 11. The pressing assembly 12 may further include a first cylinder 121, a first cylinder fork 122, a pressing rod 123, and a first cylinder seat 124. The first cylinder 121 has a push rod facing downwards and is fixed on the outer periphery of the upper end of the main shaft 11 through the first cylinder seat 124. The first cylinder fork 122 is connected to the push rod of the first cylinder 121 and moves up and down with the up and down telescoping of the push rod. The pressing rod 123 has opposite ends, wherein the first end is inserted into the first cylinder fork 122, and the opposite second end passes through the side wall of the main shaft 11 close to the pressure-resistant shell 300; the pressing rod 123 can rotate relative to the main shaft and the first cylinder fork 122 in the up and down direction.

[0091] After the first cylinder 121 is activated, it performs telescopic movements through its push rod. The first cylinder fork 122 moves up and down in the axial direction of the main shaft 11 along with the push rod. The movement of the first cylinder fork 122 drives the pressing rod 123 to rotate up and down, causing the second end of the pressing rod 123 to fit against the stepped surface on the lower part of the pressure-resistant shell 300.

[0092] In this embodiment, the first cylinder fork 122 is a vertically arranged rectangular frame body. The upper end of this rectangular frame body is fixed to the end of the push rod through fasteners such as screws. The inner bottom of the rectangular frame body is provided with a first pin shaft 125. The axial direction of the first pin shaft 125 is perpendicular to the length direction of the pressing rod 123, and the first pin shaft 125 contacts the lower surface of the first end of the pressing rod 123, providing support for the pressing rod 123 without affecting its rotation. The second end of the pressing rod 123 passes through the side walls of the first cylinder seat 124 and the main shaft 11 and is close to the pressure-resistant shell 300.

[0093] Corresponding to the vertical arrangement of the first cylinder 121 outside the main shaft 11, the first cylinder seat 124 includes an interconnected vertical plate and a horizontal plate. The first cylinder 121 is fixed to the horizontal plate of the first cylinder seat 124 through locking parts and the like. The vertical plate of the first cylinder seat 124 is attached to and fixed to the outer periphery of the upper end of the main shaft 11 through locking parts and the like. The push rod of the first cylinder 121 passes downward through the horizontal plate, and the first cylinder fork 122 is connected to the end of the push rod and is also located on the side of the vertical plate facing away from the main shaft 11. The vertical plate is provided with a notch corresponding to the second end of the pressing rod 123. The second end of the pressing rod 123 passes through the notch and is rotatably connected to the vertical plate through a rotating shaft 126, and the end of the second end faces the pressure-resistant shell 300 through the notch and the side wall of the main shaft 11.

[0094] As Figure 7 shown in (1) below, when the push rod of the first cylinder 121 extends downward, it drives the first cylinder fork 122 to move downward. At the same time, it drives the pressing rod 123 to rotate around the rotating shaft 126. The first end of the pressing rod 123 located inside the first cylinder fork 122 moves downward, and the second end facing the pressure-resistant shell 300 moves upward. As Figure 7 shown in (2) below, when the push rod of the first cylinder 121 retracts upward, it drives the first cylinder fork 122 to move upward. At the same time, it drives the pressing rod 123 to rotate around the rotating shaft 126. The second end of the pressing rod 123 facing the pressure-resistant shell 300 rotates downward and fits against the lower stepped surface of the pressure-resistant shell 300. At the same time, it can drive the main shaft 11 and the entire positioning mechanism 10 to lift upward relative to the pressure-resistant shell 300.

[0095] As Figures 4 - 6As shown in the figure, the turning component 13 may include a second cylinder 131, a second cylinder fork 132, a first lever 133, a first block 135, and a second cylinder base 134. The second cylinder 131 is horizontally arranged relative to the main shaft 11 and is fixed to the outer periphery of the upper end of the main shaft 11 through the second cylinder base 134. The push rod of the second cylinder 131 extends horizontally. The second cylinder fork 132 is rotatably connected to the push rod of the second cylinder 131 through a rotating shaft. When the push rod expands and contracts, it drives the second cylinder fork 132 to rotate in the horizontal direction. The first lever 133 is connected below the second cylinder fork 132 and extends along the axial direction of the main shaft 11. The first lever 133 can rotate self - rotatably as the second cylinder fork 132 rotates. A first channel 110 that penetrates up and down is provided in the side wall of the main shaft 11. The first lever 133 is inserted into the first channel 110. The first block 135 is arranged at the lower end of the first lever 133 and is located outside the lower end opening of the first channel 100 and can rotate with the first lever 133.

[0096] When the second cylinder 131 is started, it performs telescopic actions through its push rod. The second cylinder fork 132 rotates in the horizontal direction on the outer periphery of the main shaft 11 along with the push rod, thereby driving the first lever 133 to rotate, driving the first block 135 to rotate out and abut against the bottom end face of the lower part of the pressure - resistant shell 300 or retract and leave the bottom end face of the pressure - resistant shell 300, as Figure 7 shown in (2) to (1) in the figure.

[0097] In order to uniformly position the main shaft 11 in the circumferential direction, the turning component 13 further includes a toothed ring 136, a turning gear 137, a pressing cap 138, a connecting rod 139, and at least one second lever 140, etc., which are connected in an interlocking manner with the second cylinder fork 132.

[0098] Among them, the toothed ring 136 is rotatably sleeved on the upper end of the main shaft 11. The turning gear 137 is arranged at the upper end of the first lever 133 and meshes with the toothed ring 136. The pressing cap 138 is arranged on the turning gear 137 and is limited above the toothed ring 136 to prevent the toothed ring 136 from moving up and down on the main shaft 11. The connecting rod 139 is rotatably connected between the pressing cap 138 and the second cylinder fork 132. The connecting rod 139 is provided with a flat position that cooperates with the flat position of the pressing cap 138 and is locked by a set screw, etc. When the second cylinder 131 is started and performs telescopic actions through the push rod, it drives the second cylinder fork 132 and the connecting rod 139 to rotate in sequence. The connecting rod 139 drives the turning gear 137 to rotate through the pressing cap 138. The turning gear 137 drives the first lever 133 below it and the toothed ring 136 meshing with it to rotate.

[0099] The second lever 140 extends along the axial direction of the main shaft 11. A second channel (not shown) that penetrates up and down is provided inside the side wall of the main shaft 11, and the second lever 140 is inserted into the second channel. A linkage gear 142 is provided at the upper end of the second lever 140 and meshes with the toothed ring 136. A second dial block 141 is provided at the lower end of the second lever 140. The second air cylinder 131 acts and drives the toothed ring 136 to rotate through the second air cylinder fork 132, the connecting rod 139, and the rotating gear 137. The rotation of the toothed ring 136 drives the second lever 140 to rotate through the linkage gear 142, and then drives the second dial block 141 to rotate out and abut against the bottom end face of the lower part of the pressure-resistant shell 300 or retract and leave the bottom end face, similar to the rotation and action of the first lever 133 and the first dial block 135.

[0100] In addition, a pressing cap is also provided on each linkage gear 142, which is used to limit above the toothed ring 136 to prevent the toothed ring from moving up and down on the main shaft 11.

[0101] In this embodiment, as Figure 4 and Figure 6 shown, there are two second levers 140, which are evenly spaced along the circumferences of the main shaft 11 and the toothed ring 136 together with the first lever 133.

[0102] Combined with Figure 3 , 8 and Figure 9 , the clamping mechanism 20 may include a support cylinder 22, a suspension flange 21, and a clamping cylinder 23 that are respectively sleeved on the outer periphery of the pressure-resistant shell 300, and also includes at least one third air cylinder 24 and at least one set of clamping execution components.

[0103] The support cylinder 22 is connected above the main shaft 11 through fasteners such as bolts or screws. The suspension flange 21 is connected above the support cylinder 22 through several columns 211 and is used to connect with the hoisting assembly 500. The clamping cylinder 23 is sleeved on the outer periphery of the support cylinder 22, and the top height of the clamping cylinder 23 is lower than the top height of the support cylinder 22. Therefore, the top of the clamping cylinder 23 is located below the top of the support cylinder 22. A plurality of lifting rings 210 are provided on the suspension flange 21 for connecting the hoisting assembly 500.

[0104] The third air cylinder 24 is connected to the clamping cylinder 23 and the support cylinder 22, and can drive the clamping cylinder 23 to move up and down axially relative to the support cylinder 22 through its action. Specifically, in Figure 8 and Figure 9In the illustrated embodiment, the tops of the clamping cylinder 23 and the support cylinder 22 are respectively provided with flanges protruding radially outward, and the flanges of the support cylinder 22 are spaced apart from each other in the upper and lower directions. The third cylinder 24 is vertically fixed below the flange of the clamping cylinder 23 by fasteners, and the push rod 241 of the third cylinder 24 is arranged upward, passing through the flange of the clamping cylinder 23 and connecting the flange of the support cylinder 22, so that when the third cylinder 24 is started, the push rod 241 thereof can be extended and retracted to drive the clamping cylinder 23 to move up and down relative to the support cylinder 22.

[0105] The clamping actuator is connected between the clamping cylinder 23 and the main shaft 11, and can be clamped on the main shaft 11 as the clamping cylinder 23 moves up and down. When the clamping actuator includes multiple groups, the multiple groups of clamping actuators are arranged at intervals along the circumference of the clamping cylinder 23.

[0106] Furthermore, combined with Figures 9 - 12 Each clamping actuator assembly may include a clamping plate 25, a first clamping block 26 and a second clamping block 27 respectively arranged at the upper and lower ends of the clamping plate 25. The clamping plate 25 has a certain length, and is arranged on the inner side of the main shaft 11 along the axial extension of the main shaft 11. The top of the clamping plate 25 is connected to the clamping cylinder 23 through a hinge assembly 28. The first clamping block 26 is arranged in the upper end of the main shaft 11 relative to the upper end of the clamping plate 25, and the second clamping block 27 is arranged in the lower end of the main shaft 11 relative to the lower end of the clamping plate 25. The upper end of the clamping plate 25 is provided with a first guide inclined surface 251 that cooperates with the first clamping block 26, and the lower end of the clamping plate 25 is provided with a second guide inclined surface 252 that cooperates with the second clamping block 27. The third cylinder 24 is actuated to drive the clamping tube 23 to move upward relative to the supporting tube 22, thereby driving the clamping plate 25 to move upward. The clamping plate 25 is retracted toward the axis of the pressure hull 300 by cooperating with the inclined surfaces of the first clamping block 26 and the second clamping block 27, thereby being clamped on the pressure hull 300.

[0107] The holding plate 25 is provided with a concave guide groove through the first guide slope 251 and the second guide slope 252. Figure 12 As shown in (1), when the clamping plate 25 is clamping the pressure-resistant shell 300, the protruding portion of the first clamping block 26 fits in the guide groove at the upper end of the clamping plate 25, and the protruding portion of the second clamping block 27 fits in the guide groove at the lower end of the clamping plate 25. Figure 12 As shown in (2), when the clamping plate 25 is driven to move upward, the protruding portion of the first clamping block 26 moves downward along the corresponding guide groove until it cooperates with the first guide slope 251 and moves downward along the first guide slope 251, while driving the clamping plate toward the axial direction of the pressure-resistant shell 300; similarly, the protruding portion of the second clamping block 27 moves downward along the corresponding guide groove until it cooperates with the second guide slope 252 and moves downward along the second guide slope 252, while driving the clamping plate 25 toward the axial direction of the pressure-resistant shell 300.

[0108] As shown in Figure 8 and Figure 9 shown, as the connection structure between the clamping cylinder 23 and the clamping plate 25, the hinge assembly 28 further includes a first hinge seat 281, a second hinge seat 282 and a connecting piece 283. The first hinge seat 281 is fixed on the clamping cylinder 23, the second hinge seat 282 is fixed on the top of the clamping plate 25, and the connecting piece 283 is rotatably connected between the first hinge seat 281 and the second hinge seat 282 through a rotating shaft. The clamping cylinder 23 is driven by the third cylinder 24 to move up and down, and drives the clamping plate 25 to move through the first hinge seat 281, the connecting piece 283 and the second hinge seat 282.

[0109] The clamping execution assembly further includes at least two groups of guiding screws for movably positioning the clamping plate 25 inside the main shaft 11. Corresponding to the arrangement of the guiding screws, guiding grooves 250 are respectively provided on the opposite sides of the upper end and the lower end of the clamping plate 25, and the extending direction of the guiding grooves 250 is parallel to the up-and-down movement direction of the clamping plate 25. Each group of guiding screws corresponds to the upper end and the lower end of the clamping plate 25 respectively. The two guiding screws 253 of each group of guiding screws are respectively distributed on both sides of the upper end or the lower end of the clamping plate 25. Each guiding screw 253 is arranged inside the main shaft 11, and one end faces and cooperates with the guiding groove 250. When the clamping plate 25 moves up and down along the axial direction of the main shaft 11, the guiding screw 253 moves up and down along the corresponding guiding groove 250.

[0110] Preferably, as shown in Figure 11 shown, the clamping mechanism 20 includes three groups of clamping execution assemblies, and the three groups of clamping execution assemblies are evenly spaced along the circumferential direction of the main shaft 11.

[0111] Furthermore, in order to prevent the clamping mechanism 20 from failing to clamp the pressure-resistant shell 300 due to problems such as the failure of the third cylinder 24, the clamping mechanism may further include an anti-falling component. The anti-falling component further includes an anti-falling rod 29 and an anti-falling block 291; the anti-falling rod 29 is arranged between the clamping cylinder 23, the support cylinder 22 and the suspension flange 21, and the anti-falling block 291 is fitted at the lower end of the anti-falling rod 29 and fixed on the clamping cylinder 23 through a locking member. After the clamping cylinder 23 moves upward to drive the clamping execution assembly to clamp the pressure-resistant shell 300, the anti-falling rod 29 is tightened to make the relative fixation between the suspension flange 21, the support cylinder 22 and the clamping cylinder 23.

[0112] Among them, the anti-falling rod 29 is mainly arranged on the suspension flange 21, the flange 221 of the support cylinder 22 and the flange 231 of the clamping cylinder 23. Threads are provided at the lower end of the anti-falling rod 29. The anti-falling block 291 is arranged on the lower surface of the flange 231 of the clamping cylinder 23 and is fastened to the flange 231 through screws. And the anti-falling block 291 is in threaded cooperation with the lower end of the anti-falling rod 29 through a threaded hole to achieve locking.

[0113] The cutting mechanism 30, as the main actuator for cutting, is positioned outside the pressure-resistant housing 300 through cooperation with the main shaft 11. Refer to Figure 3 , Figure 13 and Figure 14 , the cutting mechanism 30 may specifically include an inner housing 31, an outer housing 32, a rotary gear 33, a first differential gear 34, a driving element 35, a transmission shaft 36, an intermediate gear 37, a second differential gear 38, a cutting disc 39, and at least one cutting tool assembly 310.

[0114] The inner housing 31 is sleeved on the main shaft 11 and is rotatable relative to the main shaft 11. The outer housing 32 is sleeved outside the inner housing 31 and is relatively fixed to the main shaft 11. Corresponding to the settings of the inner housing 31 and the outer housing 32 of the cutting mechanism 30, a radially protruding annular step 111 is provided on the outer peripheral surface of the main shaft 11. The annular step 111 can axially divide the main shaft 11 into upper and lower parts, and the cutting mechanism 30 is mainly arranged outside the lower part of the main shaft 11.

[0115] Wherein, a bearing assembly 3 is provided between the inner housing 31 and the outer housing 32. The bearing assembly 3 may include two bearings arranged up and down, and the two bearings are separated by a spacer sleeve. The inner housing 31 and the outer housing 32 are not connected. The top of the outer housing 32 is locked on the outer periphery of the main shaft 11 (specifically, the annular step 111 of the main shaft 11) through fasteners such as screws, and an end cover 321 is provided at the lower end of the outer housing 32. The inner housing 31 is relatively close to the outer peripheral surface of the main shaft 11. The upper shoulder of the inner housing 31 abuts against the upper end surface of the bearing assembly 3, and a limit ring 311 is provided at the lower part of the inner housing 31 to be restricted at the lower end of the bearing assembly 3.

[0116] The rotary gear is sleeved on the main shaft 11 and is connected to one end of the inner housing 31, and is relatively fixed to the inner housing 31. The first differential gear 34 is sleeved outside the inner housing 31. The driving element 35 is fixed on the outer housing 32 through a box body, and its shaft end extends downward; a driving gear 351 is provided at the shaft end of the driving element 35. The driving element 35 can be selected as a motor or a pneumatic motor, etc.

[0117] The transmission shaft 36 is fixed to the housing 32 through the box body and is arranged in parallel at an interval from the shaft end of the driving element 35. The upper and lower ends of the transmission shaft 36 are respectively fixed in the box body by shaft snap rings, bearings and hole snap rings. The intermediate gear 37 and the second differential gear 38 are coaxially arranged on the transmission shaft 36. The slewing gear 33 is respectively in the same horizontal plane as the driving gear 351 and the intermediate gear 37 and is meshed therewith. The second differential gear 38 is meshed with the first differential gear 34. In this way, after the driving element 35 is started, the rotation of the shaft end drives the slewing gear 33 meshed therewith to rotate through the driving gear 351. The rotation of the slewing gear 33 drives the intermediate gear 37 meshed therewith to rotate. The intermediate gear 37 drives the second differential gear 38 coaxially arranged therewith to rotate. The second differential gear 38 drives the first differential gear 34 meshed therewith to rotate.

[0118] The cutting disc 39 is sleeved on the outer periphery of the main shaft 11 and fixed on the slewing gear 33. The cutter assembly 310 is arranged on the cutting disc 39 and is aligned with the Ω seal weld 600 between the lower part of the pressure-resistant shell 300 and the pipe socket 400. The cutter assembly 310 can move back and forth along the radial direction of the cutting disc 39, so as to cut the Ω seal weld 600.

[0119] As Figure 14 and Figure 15 shown, the cutter assembly 310 may further include a tool holder 3101 and a cutter 3102 mounted on the tool holder 3101. The cutting disc 39 is provided with a chute 391 extending along the radial direction of the cutting disc 39. A guide rail 392 is provided on the chute 391. The tool holder 3101 is fitted on the guide rail 392 and can move back and forth along the guide rail 392. The cutter 3102 moves with the tool holder 3101. The cutter 3102 can be selectively fixed on the tool holder 3101 through a plurality of mounting positions, and the corresponding mounting position can be selected according to needs for fixing, so as to realize the adjustable position of the cutter 3102 on the tool holder 3101.

[0120] In the present invention, both the first differential gear 34 and the second differential gear 38 are differential gears. The first differential gear 34 is a large differential gear relative to the second differential gear 38. Therefore, a difference will be generated between the angular velocities after the two rotate.

[0121] Reference Figures 14 - 16, a cam track groove 341 is provided on the first differential gear 34. The cam track groove 341 is a groove provided on the surface of the first differential gear 34, and the shape of the groove is similar to that of a cam. The cutter assembly 310 is fitted on the cam track groove 341 of the first differential gear 34 through the positioning shaft 320. After the driving element 35 is started, the driving gear 351 drives the rotating gear 33 to rotate at a first angular velocity. At the same time, the intermediate gear 37 and the second differential gear 38 also rotate at the first angular velocity. The second differential gear 38 drives the first differential gear 34 to rotate at a second angular velocity. A relative differential speed is generated between the rotating gear 33 and the first differential gear 34, so that the rotation of the first differential gear 34 drives the positioning shaft 320 to move along the cam track groove 341, and then drives the cutter assembly 310 to move relative to the cutting disc 39 in the directions of approaching and departing from the Ω seal weld 600, realizing the feed and retraction of the Ω seal weld 600 for cutting.

[0122] Combined with Figure 15 , Figure 17 and Figure 18 , corresponding to the setting of the positioning shaft 320, the bottom surface of the sliding groove 391 of the cutting disc 39 and the rotating gear 33 are provided with relatively communicating moving guide grooves 393 and 331. The moving guide grooves 393 and 331 are strip-shaped grooves extending along the moving direction of the cutter assembly 310. One end of the positioning shaft 320 is fixed on the tool holder 3101, and the other end passes through the sliding groove 391 and the moving guide grooves 393 and 331 of the rotating gear 33 and is fitted in the cam track groove 341 of the first differential gear 34.

[0123] In the cutting mechanism 30, let the number of teeth and module of the driving gear 351 be N1 and M1 respectively, the number of teeth and module of the rotating gear 33 be N2 and M2 respectively, and the number of teeth and module of the intermediate gear 37 be the same as those of the driving gear 351, i.e., N1 and M1; the number of teeth and module of the second differential gear 38 be N3 and M3 respectively, and the number of teeth and module of the first differential gear 34 be N4 and M4 respectively; where N4 > N2 > N3 > N1, M1 = M2, M3 = M4, and M1 > M3. When the driving element 35 operates, it drives the driving gear 351 to rotate at an angular velocity V. Since the rotating gear 33 meshes with the driving gear 351 and the intermediate gear 37 respectively, the rotating gear 33 will rotate at a corresponding angular velocity V1, and the intermediate gear 37 will rotate at the same angular velocity V. Since the second differential gear 38 is coaxial with the intermediate gear 37 and meshes with the first differential gear 34, the angular velocity of the second differential gear 38 is the same as the angular velocity V of the intermediate gear 37, and the first differential gear 34 rotates at a corresponding angular velocity V2, where V > V1 > V2. Due to the setting of the number of teeth and module of each gear, after the driving gear 351 rotates one circle, there will be a difference between the angular velocity V1 of the rotating gear 33 and the angular velocity V2 of the first differential gear 34. Under this influence, the positioning shaft 320 will move within the cam track groove 341 of the first differential gear 34, thereby driving the tool rest 3101 to move back and forth in the axial direction, realizing the cutting of the Ω sealing weld 600 between the lower part of the pressure-resistant shell 300 and the pipe socket 400 by the cutting tool 3102.

[0124] Combined with Figure 3 , Figure 19 and Figure 20 , the material receiving mechanism 40 is arranged on the outer periphery of the pipe socket 400 and is used to collect the debris that falls during the cutting operation of the cutting mechanism 30.

[0125] Specifically, the material receiving mechanism 40 may include an outer cover body 41 arranged on the outer periphery of the pipe socket 400, multiple sets of expansion and contraction components 42 arranged inside the outer cover body 41, and a fireproof cloth 43. The multiple sets of expansion and contraction components 42 are arranged at intervals along the circumferential direction of the pipe socket 400 on the inner bottom surface of the outer cover body 41, and can be rotatably clamped on the pipe socket 400 or expanded away from the pipe socket 400 relative to the outer cover body 41. The fireproof cloth 43 is arranged on the inner bottom surface of the outer cover body 41 and covers the expansion and contraction components 42, defining a collection space between the outer cover body 41 and the fireproof cloth 43 to receive the debris that falls during cutting.

[0126] The outer cover body 41 may further include a bottom plate 411 sleeved on the outer periphery of the pipe socket 400, a hanging frame 412 vertically connected to the periphery of the bottom plate 411, a surrounding plate 413 surrounding the hanging frame 412 on all sides, and a supporting leg 414 connected to the lower end of the bottom plate 411 and used to support on the top cover 200 of the pressure vessel. The top of the hanging frame 412 is fixedly connected to the outer periphery of the main shaft 11 of the positioning mechanism 10.

[0127] The outer cover 41 has a central through hole for passing through the socket 400. A raised support ring column 415 is provided on the outer periphery of the central through hole. A converging and diverging ring 416 is provided on the inner bottom surface of the outer cover 41. The converging and diverging ring 416 is movably sleeved on the outer periphery of the support ring column 415.

[0128] A plurality of sets of converging and diverging assemblies 42 are arranged at intervals along the circumferential direction of the support ring column 415 and are connected to the converging and diverging ring 416 and the support ring column 415. The feeding mechanism 40 further includes a driving unit 44. The driving unit 44 is connected to the converging and diverging ring 416 and drives the converging and diverging ring 415 to move up and down, driving the converging and diverging assemblies 42 to rotate and clamp on the socket 400 relative to the support ring column 415 and the converging and diverging ring 416 (as Figure 19 shown) or expand away from the socket 400 (as Figure 20 shown).

[0129] As Figure 20 and Figure 21 shown, the converging and diverging assembly 42 includes a converging and diverging rod 421, a first connecting seat 422, a second connecting seat 423, and a connecting member 424. The converging and diverging rod 421 includes a converging and diverging rod body 4211 and a hinged section 4212 angularly connected to the end of the converging and diverging rod body 4211; the hinged section 4212 is angularly connected to the converging and diverging rod body 4211, so that the converging and diverging rod 421 is integrally similar to an L-shaped structure. The first connecting seat 422 is arranged on the support ring column 415, and the second connecting seat 423 is arranged on the converging and diverging ring 416; the converging and diverging rod body 4211 is vertically arranged on the support ring column 415. The hinged section 4212 has opposite ends, and one end connected to the converging and diverging rod body 4211 is rotatably connected to the first connecting seat 422, and the other end of the hinged section 4212 far from the converging and diverging rod body 4211 is rotatably connected to the second connecting seat 423 through the connecting member 424.

[0130] When the converging and diverging ring 416 is driven to move up and down, it drives the second connecting seat 423 thereon to move, and also drives the converging and diverging rod 421 to rotate relative to the first connecting seat 422 and the connecting member 424 through the connecting member 424. The rotation direction of the converging and diverging rod 421 is the direction of approaching and departing from the socket 400. In order to better hold the socket 400, a plate body 4213 can be provided at the end of the converging and diverging rod body 4211 far from the hinged section 4212, which can be attached to the socket 400 with a larger area.

[0131] In addition, the vertical movement of the expansion and contraction ring 416 is driven by the driving unit 44. In order to enable the overall smooth vertical movement of the expansion and contraction ring 416, the driving unit 44 includes at least two cylinders. The cylinders can be arranged at the lower part of the outer housing 41, and the push rods of the cylinders penetrate into the outer housing 41 and are connected to the expansion and contraction ring 416. The end of the push rod can be further connected to the expansion and contraction ring 416 through an arc-shaped member 417. There are two connection points between the arc-shaped member 417 and the expansion and contraction ring 416, and the two connection points are located on the opposite sides of a second connection seat 423. In this way, each cylinder can increase the connection points with the expansion and contraction ring 416 through the arc-shaped member 417, and can realize the smooth vertical movement of the overall expansion and contraction ring 416 while setting a smaller number of cylinders.

[0132] Combined Figure 2 , Figure 3 , Figure 7 , Figure 9 , Figure 12 and Figure 14 When using the lower seal weld cutting device of the control rod drive mechanism of the present invention to cut the seal weld, the corresponding lower seal weld cutting method of the control rod drive mechanism includes the following steps:

[0133] S1. Lift the lower seal weld cutting device 100 of the control rod drive mechanism through the hoisting assembly 500, and pass through the pressure-resistant shell 300 of the control rod drive mechanism until reaching the lower position of the connecting pipe seat 400 of the pressure-resistant shell 300.

[0134] S2. Through the cooperation of the positioning mechanism 10 of the lower seal weld cutting device 100 of the control rod drive mechanism with the lower part of the pressure-resistant shell 300, position the lower seal weld cutting device 100 of the control rod drive mechanism on the outer periphery of the pressure-resistant shell 300. At the same time, the cutting mechanism 30 of the lower seal weld cutting device 100 of the control rod drive mechanism corresponds to the outside of the Ω seal weld 600 between the lower part of the pressure-resistant shell 300 and the pipe seat 400.

[0135] S3. The clamping mechanism 20 of the lower seal weld cutting device 100 of the control rod drive mechanism acts to clamp on the outer periphery of the pressure-resistant shell 300. The material receiving mechanism 40 converges and clamps the pipe seat 400.

[0136] S4. The cutting mechanism 30 acts, and cuts the Ω seal weld 600 through its cutter assembly 310.

[0137] During the cutting of the Ω seal weld 600, the debris generated falls into the material receiving mechanism 40.

[0138] S5. After the cutting is completed, the cutting mechanism 30 acts to retract the cutter assembly 310 to the initial position, the clamping mechanism 20 releases the clamping of the pressure-resistant shell 300, and the positioning mechanism 10 releases the positioning action.

[0139] S6. Lift the lower seal weld cutting device 100 of the control rod drive mechanism by the hoisting assembly 500 and disengage it from the pressure vessel 300.

[0140] In summary, when cutting the seal weld between the lower part of the pressure vessel and the nozzle using the lower seal weld cutting device of the control rod drive mechanism of the present invention, there is no need for manual approach to the highly radioactive pressure vessel, and automatic cutting operation can be achieved. It has high working efficiency and greatly compresses the overhaul and maintenance time of the nuclear reactor unit; it solves the problem of automatic positioning in an environment where manual access and intervention are impossible, with high positioning accuracy and simple operation.

[0141] The structure of the present invention is compact, can adapt to operations in narrow spaces, and is applicable to all pressure vessels with dense distribution.

[0142] The above are only embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural or equivalent process transformation made using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A cutting device for the lower sealing weld of a control rod drive mechanism, characterized in that, It is installed on the lower part of the pressure-resistant shell of the control rod drive mechanism and the outer side of the pipe seat; the lower seal weld cutting device of the control rod drive mechanism includes a positioning mechanism, a clamping mechanism and a cutting mechanism; The positioning mechanism is used to be positioned on the outer periphery of the lower part of the pressure-resistant shell, and the clamping mechanism is connected above the positioning mechanism for clamping the outer periphery of the pressure-resistant shell; The cutting mechanism is connected below the positioning mechanism and is used to be fixed on the outer periphery of the lower part of the pressure-resistant shell. The Ω seal weld between the lower part of the pressure-resistant shell and the pipe seat is cut by aligning with the cutter assembly; The positioning mechanism includes a main shaft sleeved on the outer periphery of the lower part of the pressure-resistant shell, at least one set of pressing components arranged on the main shaft, and a turning component arranged on the main shaft; The pressing component includes a first cylinder with a push rod facing downwards, a first cylinder fork connected to the push rod of the first cylinder, and a pressing rod with its first end passing through the first cylinder fork. The opposite second end of the pressing rod passes through the side wall of the main shaft close to the pressure-resistant shell; the first cylinder acts and drives the pressing rod to rotate up and down through the first cylinder fork, driving the second end of the pressing rod to fit with the step surface at the lower part of the pressure-resistant shell; The turning component includes a second cylinder with a push rod extending horizontally, a second cylinder fork rotatably connected to the push rod of the second cylinder, a first turning rod and a first turning block connected below the second cylinder fork; a first through channel penetrating up and down is arranged in the side wall of the main shaft, the first turning rod is arranged in the first through channel, and the first turning block is arranged at the lower end of the first turning rod and located outside the lower end opening of the first through channel; the second cylinder acts and drives the first turning rod to rotate through the second cylinder fork, driving the first turning block to rotate out and abut against the bottom end surface of the lower part of the pressure-resistant shell or retract and leave the bottom end surface.

2. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 1, characterized in that, The pressing component further includes a first cylinder seat; The first cylinder is fixed on the outer periphery of the upper end of the main shaft through the first cylinder seat; The first cylinder fork is a vertically arranged rectangular frame body, and a first pin shaft is arranged at the inner bottom of the rectangular frame body, and the first pin shaft contacts the lower surface of the first end of the pressing rod; the second end of the pressing rod passes through the vertical plate of the first cylinder seat and is rotatably connected to the vertical plate through a rotating shaft.

3. The cutting device for the lower sealing weld of the control rod drive mechanism according to claim 1, wherein The turning component further includes a toothed ring, a turning gear, a pressing cap, a connecting rod and at least one second turning rod; The toothed ring is rotatably sleeved on the upper end of the main shaft, the turning gear is arranged at the upper end of the first turning rod and meshes with the toothed ring, the pressing cap is arranged on the turning gear and is limited above the toothed ring to prevent the toothed ring from moving up and down on the main shaft; the connecting rod is rotatably connected between the pressing cap and the second cylinder fork; A second through channel penetrating up and down is arranged in the side wall of the main shaft, and the second turning rod is arranged in the second through channel; a linkage gear meshing with the toothed ring is arranged at the upper end of the second turning rod, and a second turning block is arranged at the lower end of the second turning rod; The second cylinder is actuated to drive the gear ring to rotate through the second cylinder fork, the connecting rod and the shifting gear. The rotation of the gear ring drives the second shifting rod to rotate through the linkage gear, thereby driving the second shifting block to rotate out to abut the bottom end surface of the lower part of the pressure hull or to retract and leave the bottom end surface.

4. The cutting device for the lower sealing weld of the control rod drive mechanism according to claim 1, characterized in that The clamping mechanism includes a support cylinder sleeved on the outer periphery of the pressure-resistant shell and connected to the top of the main shaft, a hanging flange connected to the top of the support cylinder and connected to the hanging assembly, a clamping cylinder sleeved on the outer periphery of the support cylinder, a third cylinder connected to the clamping cylinder and the support cylinder, and at least one set of clamping actuator components; The clamping actuator assembly includes a clamping plate extending along the axial direction of the main shaft and arranged on the inner side of the main shaft, and a first clamping block and a second clamping block respectively arranged on the main shaft corresponding to the upper and lower ends of the clamping plate; the top of the clamping plate is connected to the clamping cylinder through a hinge assembly, the upper end of the clamping plate is provided with a first guiding inclined surface matched with the first clamping block, and the lower end of the clamping plate is provided with a second guiding inclined surface matched with the second clamping block; The action of the third cylinder drives the clamping tube to move upward relative to the supporting tube, thereby driving the clamping plate to move upward. The clamping plate is retracted toward the axis of the pressure shell by cooperating with the inclined surfaces of the first clamping block and the second clamping block, thereby being clamped on the pressure shell.

5. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 4, characterized in that, The hinge assembly comprises a first hinge seat, a second hinge seat and a connecting piece; The first hinged seat is fixed on the clamping tube, the second hinged seat is fixed on the top of the clamping plate, and the connecting piece is rotatably connected between the first hinged seat and the second hinged seat.

6. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 4, characterized in that, The clamping actuator assembly also includes at least two sets of guide screws; Guide grooves are respectively provided on the opposite side surfaces of the upper end and / or the lower end of the clamping plate, and the extension direction of the guide groove is parallel to the up and down movement direction of the clamping plate; the guide screw is inserted into the main shaft, and one end faces and fits in the guide groove.

7. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 4, characterized in that, The clamping mechanism also includes an anti-falling rod and an anti-falling block; The anti-falling rod is arranged between the clamping tube, the supporting tube and the hanging flange, and the anti-falling block is matched with the lower end of the anti-falling rod and is fixed on the clamping tube through a locking piece.

8. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 1, wherein The cutting mechanism comprises an inner shell sleeved on the main shaft and rotatable relative to the main shaft, an outer shell sleeved on the outer side of the inner shell and fixed relative to the main shaft, a rotary gear sleeved on the main shaft and connected to one end of the inner shell, a first differential gear sleeved on the outer side of the inner shell, a driving element fixed on the outer shell, a transmission shaft fixed on the outer shell and arranged parallel to the shaft end of the driving element, a transition gear and a second differential gear coaxially arranged on the transmission shaft, a cutting disc and at least a cutting assembly; A driving gear is provided at the shaft end of the driving element, the rotary gear is meshed with the driving gear and the transition gear respectively, and the second differential gear is meshed with the first differential gear; The cutting disc is sleeved on the outer periphery of the main shaft and fixed on the rotary gear, and the cutter assembly is arranged on the cutting disc and aligned with the Ω sealing weld between the lower part of the pressure-resistant shell and the pipe seat; The first differential gear is provided with a cam track groove, and the cutter assembly is fitted on the cam track groove of the first differential gear through a positioning shaft; After the driving element operates, it drives the rotary gear to rotate at a first angular velocity through the driving gear. At the same time, the intermediate gear and the second differential gear also rotate at the first angular velocity. The second differential gear drives the first differential gear to rotate at a second angular velocity. The rotation of the first differential gear drives the positioning shaft to move along the cam track groove, thereby driving the cutter assembly to move relative to the cutting disc in directions approaching and departing from the Ω seal weld, so as to cut the Ω seal weld.

9. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 8, characterized in that, The cutting mechanism further includes a bearing assembly disposed between the inner shell and the outer shell; The upper shoulder of the inner shell abuts against the upper end face of the bearing assembly, and a limiting ring is provided at the lower part of the inner shell to limit it at the lower end of the bearing assembly.

10. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 8, characterized in that, The cutter assembly includes a tool holder and a cutter mounted on the tool holder; The cutting disc is provided with a chute extending radially along the cutting disc, and a guide rail is provided on the chute. The tool holder is fitted on the guide rail and can move back and forth along the guide rail; The bottom surface of the chute and the rotary gear are provided with relatively communicating moving guide grooves. One end of the positioning shaft is fixed on the tool holder, and the other end passes through the moving guide grooves and is fitted in the cam track groove of the first differential gear respectively.

11. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 8, characterized in that, The cutting mechanism further includes a box body disposed on the outer side of the outer shell; the driving element and the transmission shaft are respectively disposed in the box body.

12. The cutting device for the lower seal weld of the control rod drive mechanism according to any one of claims 1-11, characterized in that, The lower seal weld cutting device of the control rod drive mechanism further includes a material receiving mechanism disposed on the outer periphery of the pipe seat to collect the cut debris that falls; 13. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 12, characterized in that, The material receiving mechanism includes an outer cover body disposed on the outer periphery of the pipe seat, multiple sets of expanding and contracting components disposed in the outer cover body, and a fireproof cloth; The multiple sets of expanding and contracting components are arranged at intervals along the circumferential direction of the pipe seat on the inner bottom surface of the outer cover body, and can rotate relative to the outer cover body to clamp the pipe seat or expand away from the pipe seat; The fireproof cloth is disposed on the inner bottom surface of the outer cover body and covers the expanding and contracting components, defining a collection space located between the outer cover body and the fireproof cloth.

14. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 13, characterized in that, A raised support ring column is provided in the central through hole of the outer cover body, and an expandable and contractible ring that can move is provided on the inner bottom surface of the outer cover body and sleeved on the outer periphery of the support ring column; The multiple sets of expanding and contracting components are arranged at intervals along the circumferential direction of the support ring column and are connected to the expandable and contractible ring and the support ring column; The material receiving mechanism further includes a driving unit, and the driving unit is connected to the expandable and contractible ring to drive the expandable and contractible ring to move up and down, driving the expanding and contracting components to rotate relative to the support ring column and the expandable and contractible ring to clamp the pipe seat or expand away from the pipe seat.

15. The cutting device for the lower sealing weld of the control rod drive mechanism according to claim 14, characterized in that, The expanding and contracting component includes an expanding and contracting rod, a first connecting seat, a second connecting seat, and a connecting member; The first connecting seat is disposed on the support ring column, and the second connecting seat is disposed on the expandable and contractible ring; The expanding and contracting rod includes an expanding and contracting rod body and a hinged section angularly connected to the end of the expanding and contracting rod body; one end of the hinged section connecting the expanding and contracting rod body is rotatably connected to the first connecting seat, and the other end of the hinged section away from the expanding and contracting rod body is rotatably connected to the second connecting seat through the connecting member.

16. The cutting device for the lower seal weld of the control rod drive mechanism according to claim 13, wherein The outer housing includes a bottom plate sleeved on the outer periphery of the nozzle, a suspension bracket vertically connected to the periphery of the bottom plate, a surrounding plate surrounding the suspension bracket, and a support leg connected to the lower end of the bottom plate and used for supporting on the top cover of the pressure vessel; the top of the suspension bracket is fixedly connected to the outer periphery of the positioning mechanism.

17. A cutting method for the lower seal weld of a control rod drive mechanism, characterized in that, Using the control rod drive mechanism lower seal weld cutting device according to any one of claims 1-16, the control rod drive mechanism lower seal weld cutting method includes the following steps: S1. Lift the control rod drive mechanism lower seal weld cutting device through the hoisting assembly and pass it through the pressure-resistant housing of the control rod drive mechanism until it reaches the lower position where the pressure-resistant housing is connected to the nozzle. S2. Through the cooperation between the positioning mechanism of the control rod drive mechanism lower seal weld cutting device and the lower part of the pressure-resistant housing, position the control rod drive mechanism lower seal weld cutting device on the outer periphery of the pressure-resistant housing, and at the same time, the cutting mechanism of the control rod drive mechanism lower seal weld cutting device corresponds to the outside of the Ω seal weld between the lower part of the pressure-resistant housing and the nozzle. S3. The clamping mechanism of the control rod drive mechanism lower seal weld cutting device acts to clamp on the outer periphery of the pressure-resistant housing. S4. The cutting mechanism acts, and the Ω seal weld is cut by its cutter assembly.

18. The cutting method for the lower seal weld of the control rod drive mechanism according to claim 17, characterized in that, Before step S4, it further includes: The material receiving mechanism of the control rod drive mechanism lower seal weld cutting device converges and clamps the nozzle. In step S4, the debris generated during the cutting of the Ω seal weld falls into the material receiving mechanism.

19. The cutting method for the lower seal weld of the control rod drive mechanism according to claim 17 or 18, characterized in that The control rod drive mechanism lower seal weld cutting method further includes the following steps: S5. After the cutting is completed, the cutting mechanism acts to retract the cutter assembly to the initial position, the clamping mechanism releases the clamping of the pressure-resistant housing, and the positioning mechanism releases the positioning action. S6. Lift the control rod drive mechanism lower seal weld cutting device through the hoisting assembly to disengage it from the pressure-resistant housing.

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