JP2017040493A - Gate valve seat ring lapping tool and seat ring maintenance method using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gate valve seat ring lapping tool and a seat ring maintenance method capable of performing maintenance of a seat ring constituting a gate valve without cutting off a body constituting the gate valve and a pipe.SOLUTION: A gate valve seat ring lapping tool 20 comprises: a lapping plate material 21 for lapping an abutment surface of a first seat ring 12 by abutting on and oscillating the first seat ring 12; and a positioning member 22 for positioning the lapping plate material 21 on the abutment surface of the first seat ring 12. The positioning member 22 includes a flat plate 22a abutting on a second seat ring disposed to apart from the first seat ring 12 to face the first seat ring 12; a rod 22b rotatably connected to the flat plate 22a; and a fastening plate 22c screwed with the rod 22b and pressing the lapping plate material 21 against the abutment surface of the first seat ring 12.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a maintenance tool for a control rod drive water pressure control unit (hereinafter referred to as a water pressure control unit) that supplies control rod drive water to a control rod drive mechanism of a nuclear reactor, and is particularly used for a water pressure control unit. The present invention relates to a seat ring rubbing tool constituting a gate valve and a seat ring maintenance method using the tool.

For example, Patent Document 1 has been proposed as a maintenance related to a seat ring constituting a gate valve for a water pressure control unit of a nuclear reactor. Patent Document 1 includes a plurality of isolation valves (hereinafter referred to as gate valves) constituting a water pressure control unit, and each gate valve is in a valve box in which an upstream pipe and a downstream pipe are connected by welding. In the seat body fixed to the valve box with a screw, a seat ring is provided that forms a seat surface with the wedge provided at the tip of the stem. And when the seat ring is damaged, it is removed from the valve box using the removal screw hole provided in the seat body, and it is replaced with a healthy product prepared in advance, so that cutting and welding of the pipe are not required. A configuration is disclosed.
Further, as an apparatus for sliding and polishing a valve seat, for example, an apparatus described in Patent Document 2 is known. Patent Document 2 describes a valve seat sliding device that slides and polishes a valve seat provided in a valve box. The valve seat sliding device includes a driving device and a polishing disk that is rotationally driven by the driving device in order to slide the valve seat attached to the valve box. The polishing disk has a disk-shaped member, and has a plurality of non-metallic members with a polishing member such as polishing paper attached to the surface of the disk-shaped member. And the parallelism with respect to the valve seat of a grinding | polishing member is maintained because the peristaltic crankshaft which transmits the rotational drive force from the said drive device swings.

JP 60-56290 A Japanese Patent No. 2681021

According to the configuration described in Patent Document 1, it is possible to remove the seat part body having the seat ring inside from the valve box without cutting the piping. However, in the configuration described in Patent Document 1, since the seat ring is fixed to the seat portion body, the seat portion body does not perform maintenance such as replacement operation of only the seat ring or sliding operation of the seat ring. It is difficult to perform in a state of being accommodated in a box.
Moreover, in the structure described in patent document 2, it is difficult to arrange | position a large valve seat sliding apparatus to the seat ring of the gate valve installed in a narrow part, and temporarily, it describes in patent document 2 In the case of using the valve seat sliding apparatus, the piping connected to the gate valve body by welding must be cut, which may cause a reduction in maintenance workability.
Therefore, the present invention enables maintenance of the seat ring constituting the gate valve without cutting the body and the pipe constituting the gate valve, and enables easy maintenance of the seat ring in a short time. An object of the present invention is to provide a seat ring rubbing tool and a seat ring maintenance method using the tool.

  In order to solve the above problems, the gate valve seat ring rubbing tool of the present invention comprises a pair of seat rings provided in a gate valve used in a water pressure control unit for supplying drive water to a control rod drive mechanism of a nuclear reactor. A sliding tool that slides against the first seat ring to slide the abutting surface of the first seat ring, and the sliding plate material to the first seat ring. A positioning member positioned on an abutting surface of the seat ring, and the positioning member abuts on a second seat ring spaced apart from the first seat ring, and rotates on the flat plate. A rod that is movably connected; and a fastening plate that is screwed to the rod and presses the sliding plate material against the contact surface of the first seat ring. That.

  Further, the seat ring maintenance method using the gate valve seat ring rubbing tool of the present invention is a pair of gate valves provided in a gate valve used in a water pressure control unit that supplies driving water to a control rod driving mechanism of a nuclear reactor. A method for maintaining a seat ring, comprising: a preparation step of pulling out from the gate valve a stem having a wedge that contacts the pair of seat rings to form a seat surface; and a first seat ring so as to face the first seat ring A positioning member having a flat plate that abuts against a second seat ring that is spaced apart, a rod that is rotatably connected to the flat plate, and a fastening plate that is screwed to the rod. A positioning member inserting step for inserting between the seat rings, and a sliding plate for sliding the contact surface of the first seat ring on the fastening plate. A sliding plate material insertion step for inserting the cylindrical plate portion so as to be in sliding contact with the outer peripheral portion of the cylindrical portion, and the fastening plate pressing and abutting the sliding plate material against the contact surface of the first seat ring. And a sliding step of sliding the sliding plate material and sliding the contact surface of the first seat ring.

  According to the present invention, the gate that enables maintenance of the seat ring that constitutes the gate valve without cutting the body and the pipe that constitutes the gate valve, and that enables easy maintenance of the seat ring in a short time. It is possible to provide a valve seat ring rubbing tool and a seat ring maintenance method using the tool.

  Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

It is a systematic diagram of the water pressure control unit using a gate valve. It is an external view of a water pressure control unit using a gate valve. It is a longitudinal cross-sectional view of the gate valve shown in FIG. It is a longitudinal cross-sectional perspective view which shows the state by which the gate valve seat ring sliding tool of Example 1 which concerns on one Example of this invention was attached to the gate valve. It is an external view of the gate valve seat ring sliding tool shown in FIG. It is a side view of the gate valve seat ring sliding tool shown in FIG. It is a disassembled perspective view of the gate valve seat ring rubbing tool of Example 1. It is a longitudinal cross-sectional view which shows the state by which the gate valve seat ring sliding tool of Example 1 was attached to the gate valve. FIG. 9 is a cross-sectional view taken along the line AA in FIG. 8, and is an explanatory diagram of a sliding operation by a gate valve seat ring sliding tool. It is a process flow figure of maintenance work of a seat ring using the gate valve seat ring sliding tool of Example 1. It is a longitudinal cross-sectional view which shows the state by which the gate valve seat ring sliding tool of Example 2 which concerns on the other Example of this invention was attached to the gate valve. It is a longitudinal cross-sectional view which shows the state by which the gate valve seat ring sliding tool of Example 3 which concerns on the other Example of this invention was attached to the gate valve. It is an external view of the flat plate which comprises the positioning member shown in FIG. It is a longitudinal cross-sectional view which shows the state by which the gate valve seat ring sliding tool of Example 4 which concerns on the other Example of this invention was attached to the gate valve.

In the present specification, “sliding of the seat ring” means removing minute unevenness, for example, μm order unevenness generated on the contact surface of the seat ring that contacts the outer surface (side surface) of the wedge, which will be described later, This means that the abutment surface is flattened. Hereinafter, it may be referred to as “sliding work” or “cutting work”.
Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a system diagram of a water pressure control unit using a gate valve, and FIG. 2 shows an external view of the water pressure control unit using a gate valve. A hydraulic control unit (HCU) 1 of a control rod drive mechanism (not shown) for driving a control rod of a nuclear reactor is provided with a control rod drive mechanism (Control) inside a reactor pressure vessel (not shown). This is a device for controlling the water pressure of the control rod drive water supplied to the Rod Drive (CRD) or the improved control rod drive mechanism (Fine Motion Control Rod Drive: FMCRD). In the example shown in FIG. 2, the water pressure control unit 1 includes a nitrogen container 7 in the upper part, an accumulator 8 that stores scrum supply water (for example, pure water) in the lower part, a scram valve 4 and a scrum valve above the center in the height direction. The scram pilot valve 5 and the scram supply water stored in the accumulator 8 are supplied to a control rod drive mechanism (not shown) above the scram pilot valve 5, and nitrogen gas (gas phase) is supplied from the nitrogen container 7 to the scram valve 4. A plurality of pipes 2 that can be supplied to the vehicle are provided. In addition, as shown in FIG. 2, gate valves 3 a to 3 d and a ball valve 6 are respectively installed in a plurality of pipes 2 laid above the scram pilot valve 5. Note that a gate valve 3 e is installed in the vicinity of the accumulator 8 below the central portion in the height direction of the water pressure control unit 1. As shown in FIG. 2, the gate valves 3c to 3e are smaller than the gate valves 3a and 3b.

  Here, a system diagram of the water pressure control unit 1 will be described with reference to FIG. In FIG. 1, the gate valve 3e shown in FIG. 2 is omitted for convenience. As shown in FIG. 1, the nitrogen container 7 is connected to the accumulator 8 via the instrumentation block 9 by the pipe 2, and the accumulator 8 is connected to the scram valve 4 by the pipe 2. A branch pipe is provided in the pipe 2 connecting the scram valve 4 and the accumulator 8, and a gate valve 3d is provided in the branch pipe. The scram valve 4 is connected to a gate valve 3a that can supply scram supply water stored in the accumulator 8 to a control rod drive mechanism (not shown). A branch pipe is provided in the pipe 2 connecting the scram valve 4 and the gate valve 3a, and a gate valve 3c is installed in the branch pipe (pipe 2). Thus, the plurality of pipes 2 are provided with the gate valves 3a to 3d, respectively.

The ball valve 6 functions as an air supply port and supplies air to the scram pilot valve 5. The scram pilot valve 5 is provided with a three-way valve 5a. During normal operation, air supplied from the ball valve 6 is introduced through the three-way valve 5a, and the scram valve 4 is closed by this air pressure (normally closed). It is said. On the other hand, at the time of scram, the scram pilot valve 5 exhausts the air supplied from the ball valve 6 by the three-way valve 5a and stops the application of the air pressure to the scram valve 4, thereby opening the scram valve 4 to the open state. To do. As a result, the scram supply water is introduced from the accumulator 8 to the control rod drive mechanism (not shown) via the scram valve 4 and the gate valve 3a, and the control rod (not shown) is inserted into the core by the water pressure of the scram supply water.
Further, the instrumentation block 9 shown in FIG. 1 has functions of adjusting the pressure of nitrogen gas supplied from the nitrogen container 7 to the accumulator 8 and monitoring the constant pressure to detect leakage of nitrogen gas from the nitrogen container 7. Nitrogen gas from the nitrogen container 7 is used to increase the water pressure of the scram supply water introduced from the accumulator 8 to the control rod drive mechanism via the scram valve 4 and the gate valve 3a.

  Next, the gate valve 3c used in the water pressure control unit 1 shown in FIGS. 1 and 2 will be described in detail as an example. The same applies to the other gate valves 3a, 3b, 3d and 3e. FIG. 3 is a longitudinal sectional view of the gate valve 3c shown in FIG. As shown in FIG. 3, the gate valve 3 c is installed in the body 13 in which a flow path communicating the upstream side pipe 2 a and the downstream side pipe 2 b is formed inside, and in the axial direction (upstream side pipe). 2a and the downstream pipe 2b) is provided with a bonnet 15 that accommodates the stem 10 in a vertically movable manner. The body 13 and the bonnet 15 are fastened by a hexagon bolt 14 via a seal member 19b made of, for example, a rubber O-ring. The body 13 and the bonnet 15 both have a substantially circular outline in plan view and are fastened by a plurality of hexagon bolts 14 arranged at predetermined intervals along the circumferential direction. The upstream pipe 2a and the downstream pipe 2b are connected to the body 13 by, for example, socket welding. The body 13 also includes a hollow seat ring 12 so as to communicate fluid such as scram supply water or purge water that flows through the upstream pipe 2a and the downstream pipe 2b. The seat ring 12 is caulked in advance and is integrated with the body 13. The seat ring 12 forms part of a flow path that connects the upstream pipe 2a and the downstream pipe 2b, and is made of, for example, high corrosion resistance stainless steel such as SUS316 having a composition of 18Cr-12Ni-2.5Mo. Is formed.

The stem 10 that extends in the axial direction and isolates fluid such as scram supply water or purge water includes a wedge 11 at the tip and a handle 16 at the other end. The handle 16 is fixed to the stem 10 by a nut 18 via a spring washer 17, so that an operator can easily rotate the handle 16 with one hand. The stem 10 is screwed into a bonnet 15 so as to be movable up and down in the axial direction, and forms a seat surface between a wedge 11 and a seat ring 12 provided at the tip, thereby isolating a fluid. ing. In other words, as shown in FIG. 3, the wedge 11 has a side surface (inclined surface) whose width decreases as it goes downward along the axial direction, and a pair of seat rings 12 that are opposed to each other with the wedge 11 interposed therebetween. The end surface (the end surface on the wedge 11 side) has an inclined surface (hereinafter referred to as a contact surface of the seat ring) that can contact the inclined surface (side surface) of the wedge 11. As a result, when the wedge 11 and the seat ring 12 come into contact with each other, the contact surface between the wedge 11 and the seat ring 12 is sealed (fluid isolation) without leakage of fluid.
As described above, the seal member 19b is installed on the joint surface between the bonnet 15 and the body 13, and the seal member 19a is installed between the stem 10 and the inner surface of the bonnet 15 to prevent fluid leakage. Is realized.

FIG. 4 is a longitudinal sectional perspective view showing a state in which the gate valve seat ring sliding tool 20 of the present embodiment is attached to the gate valve 3c. FIG. 4 shows a state in which the bonnet 15 and the stem 10 provided with the wedge 11 at the tip end thereof are already removed as shown in FIG. In FIG. 4, the upstream piping 3a and the downstream piping 3b connected to the body 13 by welding are omitted, but in actuality, the upstream piping 3a and the downstream piping 3b are cut off. Without being connected to the body 13. As shown in FIG. 4, two openings along the circumferential direction are formed on the upper surface of the body 13 to insert the hexagon bolts 14 (FIG. 3). In FIG. 4, the opening into which the hexagon bolt 14 is inserted is simplified and shown in a circular shape.
The gate valve seat ring rubbing tool 20 includes a rubbing plate 21 and a positioning member 22. The positioning member 22 includes a flat plate 22a, a rod 22b, and a fastening plate 22c. As shown in FIG. 4, the gate is formed between the contact surfaces of the pair of seat rings 12, which until then has formed a seat surface by contacting the inclined surface of the wedge 11 provided at the tip of the stem 10. The valve seat ring rubbing tool 20 is mounted. Here, the width of the wedge 11 is, for example, 15 mm to 20 mm, and the space between the contact surfaces of the pair of seat rings 12 is a narrow portion.

The details of the structure of the gate valve seat ring sliding tool 20 will be described below. 5 shows an external view of the gate valve seat ring rubbing tool 20, FIG. 6 shows a side view of the gate valve seat ring rubbing tool 20, and FIG. 7 shows an exploded perspective view of the gate valve seat ring rubbing tool 20. Show. As shown in FIGS. 5 and 6, the flat plate 22 a, which is a constituent member of the positioning member 22 constituting the gate valve seat ring sliding tool 20, penetrates into a lower region that can come into contact with the contact surface of one seat ring 12. In addition to the opening 23, the side surface includes a pin hole 25 into which a fastening pin 26 for fastening the rod 22b is inserted. A part of the rod 22b, which is a constituent member of the positioning member 22, is fitted into a through opening 23 provided in the flat plate 22a, and is fastened to the flat plate 22a by the fastening pin 26. The fastening plate 22c, which is a constituent member of the positioning member 22, has a substantially disk shape and includes a cylindrical through-hole that can be fitted to the rod 22b at the center thereof, and an outer peripheral side on the surface facing the flat plate 22a. A plurality of convex portions extending to the through hole are provided at predetermined intervals along the circumferential direction. The shape of the convex portion is a substantially triangular shape when viewed from above, and the bottom thereof has an arc shape that is continuous with the outer periphery of the substantially disc-shaped fastening plate 22c. In the present embodiment, the plurality of convex portions are provided on the surface of the fastening plate 22c facing the flat plate 22a. However, the present invention is not limited to this. For example, it is good also as a structure which has a groove | channel which is mutually spaced apart at predetermined intervals along the circumferential direction of the fastening plate 22c, and extends to the outer peripheral side of the fastening plate 22c in the radial direction from the circumferential surface of the through hole. Moreover, the cylindrical part which stands up so that the circumference | surroundings of the said through-hole may be enclosed in the surface on the opposite side to the side which opposes the flat plate 22a of the fastening plate 22c.
Moreover, the lower plate | board area | region 21 which can contact | abut the contact surface of the other seat ring 12 has the reverse U-shaped flat plate part. The inverted U-shaped flat plate portion is in sliding contact with the outer peripheral surface of a cylindrical portion standing upright so as to surround the through hole provided in the fastening plate 22c.

  As shown in FIG. 7, the rod 22 b which is a constituent member of the positioning member 22 constituting the gate valve seat ring sliding tool 20 includes a columnar part or a cylindrical part and a peristaltic part 24. The peristaltic portion 24 has a flat plate shape, and has a tip portion approximated by a semicircle or an arc shape. Further, the swinging portion 24 has a pin hole 25 that is aligned with the pin hole 25 formed in the flat plate 22a and into which the fastening pin 26 (FIGS. 5 and 6) can be inserted. The rod 22b can be oscillated around the fastening pin 26 as a rotational axis by rotating the pivot portion 24 into a through-opening 23 formed in the flat plate 22a and being fastened to the flat plate 22a by a fastening pin 26 (rotating). Possible). Thereby, a surface that can be in contact with the contact surface of one sheet ring 12 of the flat plate 22a and a surface that can be in contact with the contact surface of the other sheet ring 12 of the sliding plate 21 are each a pair of sheets. Positioned to abut the ring 12. In addition, a thread (groove) is formed on the outer peripheral surface of the columnar portion or the cylindrical portion constituting the rod 22b, and the outer peripheral surface of the rod 22b is formed on the inner peripheral surface of the through hole of the fastening plate 22c. A screw groove that can be screwed is formed. After inserting the sliding plate 21 from above so as to straddle the cylindrical portion of the fastening plate 22c, the fastening plate 22c is screwed to the rod 22b with a jig (not shown), whereby the sliding plate 21 is moved to the other side. It is pressed against the contact surface of the seat ring 12 and fixed. Thus, the sliding plate 21 is in sliding contact with the outer peripheral surface of the cylindrical portion of the fastening plate 22c and the outer peripheral surface of the cylindrical portion of the fastening plate 22c while being in contact with the contact surface of the other seat ring 12. The fine irregularities generated on the contact surface of the seat ring 12 are removed (sliding or cutting).

FIG. 8 is a longitudinal sectional view showing a state in which the gate valve seat ring sliding tool 20 of this embodiment is attached to the gate valve 3c. FIG. 8 shows a state where the bonnet 15 shown in FIG. 3 and the stem 10 provided with the wedge 11 at the tip are already removed. As shown in FIG. 8, a positioning member 22 constituting the gate valve seat ring sliding tool 20 is inserted into a narrow portion which is a space formed between the contact surfaces of the pair of seat rings 12, and the positioning member 22 is inserted. Is arranged so as to abut against the abutment surface of one seat ring 12 (the right seat ring 12 in FIG. 8). At this time, the flat plate 22a has a fastening pin 26 (a pin hole 25 into which the fastening pin 26 is inserted because it is a longitudinal sectional view in FIG. 8) by a swinging portion 24 which is a constituent member of the rod 22b constituting the positioning member 22. Rotate around the rotation axis. Thereby, the flat plate 22a is arranged so as to conform to the inclination angle of the contact surface of the one seat ring 12, that is, to contact. Thereafter, a sliding plate 21 constituting the gate valve seat ring sliding tool 20 is inserted from above so as to straddle the cylindrical portion of the fastening plate 22c constituting the positioning member 22, and the sliding plate 21 is a fastening plate. 22c is in sliding contact with the outer peripheral surface of the cylindrical portion. Thereafter, the fastening plate 22c is screwed to the rod 22b with a jig (not shown), so that the sliding plate 21 has an inclination angle of the contact surface of the other seat ring 12 (the left seat ring in FIG. 8). Arranged to fit. That is, the rubbing plate 21 is arranged so as to conform to the inclination angle of the contact surface of the seat ring 12 by the swinging portion 24 of the rod 22b constituting the positioning member 22, and the fastening plate 22c is attached to the rod 22b. By screwing, the sliding plate 21 is pressed against and brought into contact with the contact surface of the other seat ring 12. This state is the state shown in FIG.
Thereafter, the abutting surfaces of the sheet ring 12 that abuts against the rubbing plate 21 are cut by alternately sliding the rubbing plate 21 in the depth direction of FIG. By cutting, fine irregularities present on the contact surface of the seat ring 12 are removed, and the contact surface of the seat ring 12 is flattened, whereby the contact between the wedge 11 and the seat ring 12 described in FIG. A sheet surface can be formed between the surfaces.

  FIG. 9 is a cross-sectional view taken along the line AA in FIG. 8, and is an explanatory view of the sliding operation by the gate valve seat ring sliding tool 20. In FIG. 9, the peristaltic portion 24 constituting the rod 22 b is omitted for easy understanding. As shown in FIG. 9, the fastening plate 22c screwed to the columnar portion or the cylindrical portion of the rod 22b has a substantially triangular shape as viewed from above, as indicated by hatching, and the bottom side of the fastening plate 22c has a substantially disk shape. Convex portions that are arc-shaped and continuous with the outer periphery are formed apart from each other at a predetermined interval along the circumferential direction. Further, a circle indicated by a dotted line in FIG. 9 indicates an outer peripheral portion of the seat ring 12 positioned in the depth direction with respect to the sliding plate material 21. In this state, the vicinity of the upper end portion of the sliding plate material 21 extending above the upper surface of the body 13 is gripped by the operator's finger, and alternately in the directions indicated by the arc-shaped bidirectional arrows shown in FIG. As a result, the contact surface of the seat ring 12 that contacts the sliding plate 21 is cut.

Next, a maintenance method of the seat ring 12 using the gate valve seat ring sliding tool 20 of the present embodiment will be described. FIG. 10 is a process flow diagram of maintenance work of the seat ring 12 using the gate valve seat ring sliding tool 20.
As shown in FIG. 10, first, in the preparation step (step S1), the stem 10 provided with the wedge 11 at the tip is pulled out of the gate valve 3c by the operation of the handle 16 (FIG. 3). Thereafter, the hexagon bolt 14 is removed, and the bonnet 15 is detached from the body 13. As a result, the pair of seat rings 12 in the body 13 are exposed.
Subsequently, in the positioning member insertion step (step S2), a space formed by the positioning member 22 including the flat plate 22a, the rod 22b, and the fastening plate 22c is formed between the exposed contact surfaces of the pair of seat rings 12. It is inserted into (narrow part). Then, the flat plate 22a rotates about the fastening pin 26 as the rotation axis with respect to the swinging portion 24 which is a constituent member of the rod 22b so that the flat plate 22a constituting the positioning member 22 contacts the contact surface of one seat ring 12. By doing so, it is positioned so as to match the inclination angle of the contact surface of one of the seat rings 12. Here, the peristaltic part 24 and the flat plate 22a that rotate about the fastening pin 26 are in a relative relationship.

In the rubbing plate material insertion step (step S3), the rubbing plate material 21 is inserted so as to straddle the cylindrical portion provided on the fastening plate 22c which is a constituent member of the positioning member 22. Thereby, the plate member 21 for sliding is slidably contacted with the outer peripheral surface of the cylindrical part provided in the fastening plate 22c.
In the rubbing plate material and the sheet ring contact step (step S4), the fastening plate 22c is screwed into a cylindrical portion or a cylindrical portion constituting the rod 22b by a jig (not shown), and the rubbing plate material 21 is the other. The abutment surface of the seat ring 12 is pressed against and abuts. The state at the end of step S4 is the state shown in FIG. 4 and FIG.
Subsequently, in the rubbing plate material rocking step (step S5), the rubbing plate material 21 rocks the outer peripheral surface of the cylindrical portion of the fastening plate 22c along an arcuate locus. That is, the sliding plate 21 is alternately swung in the opposite direction along the circumferential direction of the outer peripheral surface of the cylindrical portion of the fastening plate 22c while being in contact with the contact surface of the other seat ring 12. As a result, the contact surface of the other sheet ring 12 that contacts the sliding plate material 21 is slid (cut).

  After step S5 is completed, the steps from step S1 to step S5 are repeated in order to slide the contact surfaces of one of the seat rings 12 together.

As described above, according to the present embodiment, the maintenance of the seat ring 12 constituting the gate valve 3c can be performed without cutting the body 13 and the pipes (2a, 2b) constituting the gate valve 3c. It is possible to realize a gate valve seat ring sliding tool 20 and a maintenance method for the seat ring 12 using the gate valve seat ring sliding tool 20 that can easily perform the maintenance work of the seat ring 12 in time.
Further, according to the present embodiment, the rod 22b and the fastening plate 22c constituting the positioning member 22 allow the sliding plate material 21 constituting the gate valve seat ring sliding tool 20 to contact the seat ring 12 to be slid. Easy contact with the contact surface, improving maintenance workability and realizing a gate valve seat ring rubbing tool with a simple structure, so it is possible to reduce manufacturing costs and assembly costs. It becomes.

  FIG. 11 is a longitudinal sectional view showing a state in which the gate valve seat ring sliding tool of the second embodiment according to another embodiment of the present invention is attached to the gate valve. The present embodiment is different from the first embodiment in that in addition to the gate valve seat ring rubbing tool, a suction machine and a tube connected to the suction machine are provided. The other configuration is the same as that of the first embodiment, and the description of the same configuration as that of the first embodiment is omitted below. In FIG. 11, the same components as those in the first embodiment are denoted by the same reference numerals.

FIG. 11 shows a state in which the gate valve seat ring sliding tool 20 is attached to a space (narrow portion) formed between the contact surfaces of the pair of seat rings 12 in the same manner as in the first embodiment. In this state, the other end of the tube 28, one end of which is connected to the suction machine 27, is in the vicinity of the contact surface of the seat ring 12, which is in contact with the sliding plate material 21 constituting the gate valve seat ring sliding tool 20. Positioned.
As described in the first embodiment, the seat ring 12 is made of, for example, high corrosion resistance stainless steel such as SUS316. Then, the fine unevenness (μm order) generated on the contact surface of the seat ring 12 is cut by the sliding plate material 21 while sliding, and the contact surface of the seat ring 12 is flattened. A sheet surface is formed between the abutted contact surface of the seat ring 12 and the wedge 11 provided at the tip of the stem 10 to form a fluid isolation structure. Therefore, chips (made of SUS) cut from the contact surface of the seat ring 12 are fine particles of the order of μm or less, and the fine particles adhere or remain as foreign matter in the seat ring 12 or the gate valve 3c. It is assumed that When the upstream pipe 2a and the downstream pipe 2b are communicated with each other by the operation of the gate valve 3c, the foreign matter that is fine particles is a plurality of particles laid in the water pressure control unit 1 together with a fluid such as scram supply water or purge water. It will flow in the piping and may cause a failure of the water pressure control unit 1.

In this embodiment, the foreign matter that is the fine particles is sucked into the suction machine 27 through the tube 28. Specifically, in the maintenance process flow of the seat ring shown in FIG. 10 described in the first embodiment, the sliding plate material swinging process (step S5) after completion of the sliding plate material and sheet ring contact process (step S4). ) The following steps are executed before execution.
The other end of the tube 28 whose one end is connected to the suction device 27 is positioned in the vicinity of the contact surface of the seat ring 12 with which the sliding plate material 21 contacts, and the suction device 27 is activated. Thereby, during execution of step S5 shown in FIG. 10, fine particles that are chips are always sucked and removed by the suction device 27.

  According to the present embodiment, in addition to the effects of the first embodiment, it is possible to suppress the possibility of the failure of the water pressure control unit 1 caused by foreign matters mixed in the fluid.

  FIG. 12 is a longitudinal sectional view showing a state in which the gate valve seat ring sliding tool of Example 3 according to another embodiment of the present invention is attached to the gate valve. FIG. 13 shows the positioning member shown in FIG. The external view of the flat plate to perform is shown. In the present embodiment, a concave groove is formed in the flat plate 22a which is a constituent member of the positioning member 22 constituting the gate valve seat ring sliding tool 20, and the concave groove is fitted to one seat ring 12. Is different from the first embodiment. The other configuration is the same as that of the first embodiment, and the description of the same configuration as that of the first embodiment is omitted below. 12 and 13, the same reference numerals are given to the same configurations as those in the first embodiment.

  FIG. 12 shows a state in which the gate valve seat ring sliding tool 20 is attached to a space (narrow portion) formed between the contact surfaces of the pair of seat rings 12. As shown in FIG. 12, a concave groove 29 is formed in a lower region corresponding to the contact surface of one seat ring 12 in the flat plate 22 a constituting the positioning member 22, and an upper region of the concave groove 29 is formed. Is engaged with the outer peripheral surface of the upper portion of the cylindrical seat ring 12. As shown in FIG. 13, the concave groove 29 has a shape in which the inner surface of the upper region approximates a semicircle or an arc shape, and a rectangular concave portion continuous to the inner surface of the upper region extends to the lower end of the flat plate 22a. It has a shape extending opposite. That is, the concave groove 29 has a substantially inverted U shape in plan view. Note that a value that is twice the approximate semicircular diameter or the radius of curvature of the arc of the upper region of the concave groove 29 is slightly larger than the outer diameter of the seat ring 12. Thereby, in the positioning member insertion step (step S2) shown in FIG. 10, the operation of positioning the positioning member 22 with respect to one seat ring 12 is facilitated. Further, in the sliding plate material rocking step (step S5) shown in FIG. 10, vibration generated by alternately sliding the sliding plate material 21 in an arc shape while contacting the contact surface of the other seat ring 12. However, even if it is transmitted to the flat plate 22a via the fastening plate 22c and the rod 22b constituting the positioning member 22, the concave groove 29 displaces the flat plate 22a with respect to the contact surface of one seat ring 12 ( Displacement) is regulated. As a result, displacement of the gate valve seat ring rubbing tool 20 during cutting is prevented, so that the contact surface of the other seat ring 12 by the rubbing plate 21 can be flattened with higher accuracy. Become.

  In the present embodiment, the shape of the concave groove 29 formed in the flat plate 22a constituting the positioning member 22 is a substantially inverted U shape in plan view, but is not limited thereto. For example, the overall shape of the concave groove 29 may be formed in a shape approximated by a semicircle or a circular shape. Even in this case, the diameter of the approximated semicircle or circle is larger than the outer diameter of the seat ring 12.

According to the present embodiment, in addition to the effects of the first embodiment, the positioning member 22 constituting the gate valve seat ring sliding tool 20 can be easily positioned on the seat ring 12.
Further, according to the present embodiment, it is possible to prevent the positional deviation of the gate valve seat ring rubbing tool 20 during cutting of the contact surface of the seat ring 12, and to flatten the contact surface of the seat ring 12 with higher accuracy. It becomes possible to do.

  FIG. 14 is a longitudinal sectional view showing a state in which the gate valve seat ring rubbing tool of Example 4 according to another embodiment of the present invention is attached to the gate valve. In the present embodiment, metal touch is avoided on the surface of the lower region that can contact the contact surface of the seat ring 12 among the flat plate 22a that is a constituent member of the positioning member 22 that constitutes the gate valve seat ring sliding tool 20. This is different from the first embodiment in that a protective member is provided. The other configuration is the same as that of the first embodiment, and the description of the same configuration as that of the first embodiment is omitted below. In FIG. 14, the same reference numerals are given to the same configurations as those in the first embodiment.

As shown in FIG. 14, the gate valve seat ring rubbing tool 20 of this embodiment includes a protective member in a lower region that can abut against the abutment surface of one seat ring 12 of the flat plate 22 a constituting the positioning member 22. 30 is affixed. The lower region of the flat plate 22a to which the protective member 30 is attached is wider than the contact surface of one seat ring 12. Further, the protection member 30 is attached so as to cover the through-opening 23 formed in the flat plate 22a to which the swinging portion 24 of the rod 22b constituting the positioning member 22 is fitted. Here, as the protection member 30, for example, a resin nonwoven fabric, silk fabric, cotton or hemp cloth is used.
In the gate valve seat ring rubbing tool 20 of the present embodiment, in step S2 shown in FIG. 10, the positioning member 22 is formed between the contact surfaces of the exposed pair of seat rings 12 of the gate valve 3c. When inserted into the (narrow portion), and in step S4 shown in FIG. 10, the fastening plate 22c is screwed to the columnar portion or the cylindrical portion constituting the rod 22b by a jig (not shown), and the sliding plate material When the plate 21 a is pressed against and brought into contact with the contact surface of the other seat ring 12, the flat plate 22 a constituting the positioning member 22 holds the protection member 30 against the contact surface of the one seat ring 12 without using metal touch. Therefore, the possibility of damaging the contact surface of the one seat ring 12 (addition of scratches, etc.) is reduced. Further, since the protective member 30 is attached so as to cover the through opening 23 formed in the flat plate 22a constituting the positioning member 22, it is possible to prevent foreign matter from entering one seat ring 12 inside.

  In the present embodiment, the shape of the flat plate 22a constituting the positioning member 22 is the same as the shape of the flat plate 22a shown in the first embodiment, but the present invention is not limited to this. For example, it is good also as a structure which makes it the shape of the flat plate 22a shown in Example 3, and sticks the protection member 30 so that the whole ditch | groove 29 may be covered. In this case, it is desirable to attach the protective member 30 with an appropriate slack.

  According to the present embodiment, since the protective member 30 is affixed to the flat plate 22a, it is possible to reduce the possibility of damaging the contact surface of the seat ring 12 with which the flat plate 22a contacts, and It is possible to prevent foreign matter from entering inside.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace the configurations of other embodiments with respect to a part of the configurations of the embodiments.

DESCRIPTION OF SYMBOLS 1 ... Water pressure control unit 2 ... Piping 2a ... Upstream side piping 2b ... Downstream side piping 3a, 3b, 3c, 3d, 3e ... Gate valve 4 ... Scram valve 5 ... Scrum pilot valve 5a ... three-way valve 6 ... ball valve 7 ... nitrogen container 8 ... accumulator 9 ... instrumentation block 10 ... stem 11 ... wedge 12 ... seat ring 13 ... Body 14 ... Hexagon bolt 15 ... Bonnet 16 ... Handle 17 ... Spring washer 18 ... Nuts 19a, 19b ... Seal member 20 ... Gate valve seat ring rubbing tool 21 ... Sliding plate material 22 ... Positioning member 22a ... Plate plate 22b ... Rod 22c ... Fastening plate 23 ... Through opening 24 ... Pivoting part 25 ... Pin hole 26. ..Tightening Pin 27 ... suction device 28 ... Tube 29 ... groove 30 ... protective member

Claims (17)

A tool for sliding a pair of seat rings provided on a gate valve used in a water pressure control unit for supplying drive water to a control rod drive mechanism of a nuclear reactor,
A sliding plate material that slides the contact surface of the first seat ring by sliding while contacting the first seat ring;
A positioning member that positions the sliding plate material on the contact surface of the first seat ring,
The positioning member is screwed into the rod, a flat plate that comes into contact with a second seat ring that is spaced apart from the first seat ring, a rod that is pivotally connected to the flat plate, and the rod. A gate valve seat ring rubbing tool, comprising: a fastening plate for pressing the rubbing plate material against a contact surface of the first seat ring. In the gate valve seat ring rubbing tool according to claim 1,
The fastening plate includes a cylindrical portion erected so as to surround the periphery of the through-hole screwed with the rod,
The gate valve seat ring rubbing tool, wherein the rubbing plate material is slid along the outer peripheral surface of the cylindrical portion. In the gate valve seat ring rubbing tool according to claim 2,
A gate valve seat ring rubbing tool characterized in that the lower plate has an inverted U shape in the lower plate region, and the lower region is in sliding contact with the outer peripheral surface of the cylindrical portion of the fastening plate. In the gate valve seat ring rubbing tool according to any one of claims 1 to 3,
The said rod is provided with the cylindrical part screwed together with the said fastening plate, and the sliding part connected with the said flat plate so that rotation is possible, The gate valve seat ring sliding tool characterized by the above-mentioned. In the gate valve seat ring rubbing tool according to any one of claims 1 to 3,
The said rod is provided with the cylindrical part screwed with the said fastening plate, and the sliding part connected with the said flat plate so that rotation is possible, The gate valve seat ring sliding tool characterized by the above-mentioned. In the gate valve seat ring rubbing tool according to claim 4 or 5,
The flat plate has a through opening;
The peristaltic part has a shape that is flat and has a tip that is approximated by a semicircle or an arc,
The gate valve seat ring rubbing tool, wherein the sliding portion is fitted to the through opening and fastened to the flat plate by a fastening pin. In the gate valve seat ring rubbing tool according to any one of claims 1 to 6,
The first and second seat rings have a cylindrical shape;
The flat plate is provided with a concave groove on a surface facing the second seat ring,
The concave groove has a shape in which an upper region is approximated in a semicircle or an arc shape, and a lower region continuous with the upper region has a rectangular shape, and has an inverted U shape in a plan view. Gate valve seat ring rubbing tool. In the gate valve seat ring rubbing tool according to any one of claims 1 to 6,
The first and second seat rings have a cylindrical shape;
The flat plate is provided with a concave groove on a surface facing the second seat ring,
The gate grooved seat ring rubbing tool, wherein the concave groove has a semicircle or a shape approximated by a circle. In the gate valve seat ring rubbing tool according to claim 7,
The gate valve seat ring characterized in that a value of an approximate semicircle diameter or an arc curvature radius of the upper region of the concave groove is larger than an outer diameter of the first and second seat rings. Riding tool. In the gate valve seat ring rubbing tool according to claim 8,
A gate valve seat ring sliding tool characterized in that a diameter of a semicircle approximated to the concave groove or a diameter of the circle is larger than outer diameters of the first and second seat rings. In the gate valve seat ring rubbing tool according to any one of claims 1 to 9,
The said flat plate is equipped with the protection member affixed on the surface facing the said 2nd seat ring, The gate valve seat ring sliding tool characterized by the above-mentioned. In the gate valve seat ring rubbing tool according to claim 11,
The gate valve seat ring rubbing tool, wherein the protective member is at least one of a resin nonwoven fabric, a silk fabric, a cotton fabric, and a hemp fabric. A method of maintaining a pair of seat rings provided in a gate valve used in a water pressure control unit that supplies driving water to a control rod drive mechanism of a nuclear reactor,
A preparatory step of pulling out from the gate valve a stem provided with a wedge that contacts the pair of seat rings and forms a seat surface;
A flat plate that contacts a second seat ring that is spaced apart from the first seat ring, a rod that is rotatably connected to the flat plate, and a fastening plate that is screwed to the rod. A positioning member insertion step of inserting a positioning member between the first and second seat rings;
A sliding plate material inserting step of inserting a sliding plate material for sliding the contact surface of the first seat ring so as to be in sliding contact with an outer peripheral portion of a cylindrical portion provided in the fastening plate;
An abutting step of pressing the abutting plate material against the abutting surface of the first seat ring by the fastening plate;
A maintenance method for the gate valve seat ring, comprising: a step of sliding the sliding plate material and sliding the contact surface of the first seat ring. In the maintenance method of the gate valve seat ring according to claim 13,
Between the abutting step and the peristaltic step, a suction step of positioning the other end of the tube, one end of which is connected to the suction device, in the vicinity of the contact surface of the first seat ring and starting the suction device is provided. A maintenance method for a gate valve seat ring characterized by In the maintenance method of the gate valve seat ring according to claim 13 or claim 14,
The first and second seat rings have a cylindrical shape, the flat plate has a concave groove on a surface facing the second seat ring, and the upper area of the concave groove is approximated to a semicircle or an arc shape. And the lower region continuous with the upper region has a rectangular shape,
The gate valve seat ring, wherein the positioning member is inserted between the first and second seat rings so that an upper region of the concave groove engages with an outer peripheral surface of an upper portion of the second seat ring. Maintenance method. In the maintenance method of the gate valve seat ring according to any one of claims 13 to 15,
The fastening plate includes a cylindrical portion erected so as to surround the periphery of the through-hole screwed with the rod,
The gate valve seat ring maintenance method, wherein the sliding plate material is slid along the outer peripheral surface of the cylindrical portion to slide the contact surface of the first seat ring. In the maintenance method of the gate valve seat ring according to claim 16,
In the sliding plate material, the lower region has an inverted U shape, the lower region is in sliding contact with the outer peripheral surface of the cylindrical portion of the fastening plate, and swings along the outer peripheral surface of the cylindrical portion. Maintenance method of the gate valve seat ring.

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