JP2011231866A - Isolation valve, and method of replacing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an isolation valve in which damage of a seat ring due to an edge of a flow passage or the like of a valve box upon attaching the seat ring to the valve box is prevented by facilitating tolerance control of inside dimensions of the flow passage of the valve box and outside dimensions of the seat ring.SOLUTION: The isolation valve has: a bonnet attached to the upside of the valve box 41; a hole 45 communicating with the flow passage 6 of the valve box 41, opened to a bonnet side thereof; and the seat ring 70 with a seat surface abutting to an wedge of a stem at an end of the flow passage 6 of the valve box 41, the bottom facing the hole 45. Here, an screw hole is formed on an inner surface of the flow passage 6 of the valve box, a groove is formed on an head of the seat ring 70, and a screw part engaging with the screw hole formed on the inner surface of the flow passage of the valve box is arranged at a body section of the seat ring 70. Thus, the seat ring 70 is detachably attached to the flow passage of the valve box 41, and the seat ring 70 is detached/attached from/to the flow passage of the valve box through the hole 45 opened to the bonnet side of the valve box 41.

Description

  The present invention relates to a control rod drive hydraulic device for supplying control rod drive water to a control rod drive mechanism of a nuclear reactor, and more particularly to an isolation valve used in a control rod drive hydraulic pressure control unit and an isolation valve replacement method.

  A conventional isolation valve for a control rod drive water pressure control unit of a nuclear reactor has a valve box, an upstream pipe, and a downstream pipe connected by welding as shown in JP-A-60-56290. A seat ring that forms a seat surface with the stem is press-fitted into the valve box, and a wear-resistant alloy such as stellite that forms the seat surface is built up on the seat surface of the seat ring. And the said seat ring becomes the structure attached so that attachment or detachment with respect to the valve box was possible so that replacement | exchange was possible.

  Japanese Patent No. 2681021 relates to a valve box used for a general gate valve or a check valve, and in order to slide a valve seat attached to the valve box, the drive device and the drive There has been disclosed a sliding tool for a valve seat that is constituted by a polishing disk that is rotationally driven by an apparatus to polish the valve seat.

JP 60-56290 A Japanese Patent No. 2681021

When the valve box having the structure described in Japanese Patent Application Laid-Open No. 60-56290 is used as an isolation valve for a control rod drive hydraulic pressure control unit, the seat ring (seat surface) press-fitted into the seat body of the valve box is damaged. In this case, since the valve box is welded to the upstream side pipe and the downstream side pipe, the seat ring is maintained by the sliding operation of the valve seat using the tool described in Japanese Patent No. 2681021. Will do.
A tool for performing this rubbing is difficult to apply to a small-diameter isolation valve, and if the rubbing operation of the valve seat is performed manually instead of the tool, a huge amount of work time is required.

  Also, if the seat ring has a large scratch, the scratch cannot be removed by rubbing, so the seat ring is removed from the valve box, replaced with a healthy seat ring, and attached to the valve box. Since the ring is detachably attached to the valve box, cutting work between the valve box with the damaged seat ring and the upstream and downstream pipes, and the replaced sound It is possible to eliminate the need for welding work between the valve box having the product seat ring and the upstream and downstream pipes. As a result, it is possible to reduce the exposure dose of workers in a radiation environment.

However, in the isolation valve used in the control rod drive hydraulic pressure control unit described in JP-A-60-56290, it is possible to attach the seat ring to the valve box in a detachable manner. Tolerance management between the inner surface dimensions and the outer dimensions of the seat ring and the gap management of the seat members press-fitted into the seat ring are required to be strict, and there is a problem that manufacturing of a highly accurate isolation valve is required. .
In addition, when the seat ring of the valve casing of the isolation valve is attached to the valve casing, the seat ring may be damaged at the edges of the flow path of the valve casing, etc. if handled carefully. There was a problem of requiring.

  The object of the present invention is not only to replace the seat ring of the valve box constituting the isolation valve without cutting the valve box and piping of the isolation valve, but also to change the inner dimensions of the valve box and the outer dimensions of the seat ring. It is an object of the present invention to provide an isolation valve and a method for replacing the isolation valve that facilitates tolerance management and prevents the seat ring from being damaged at the edge of a flow path or the like of the valve box when the seat ring is attached to the valve box.

The present invention includes a valve box that is connected to an upstream side pipe and a downstream side pipe through which fluid flows and is connected to each other by welding, and a bonnet attached to an upper part of the valve box, a handle The valve box has a wedge provided at the end of the stem, and the valve box communicates with the flow path of the valve box to form a hole opening on the bonnet side, and the valve box facing the hole In an isolation valve that includes a seat ring having a seat surface that contacts the wedge of the stem at the end of the flow path, and isolates the flow path of the valve box by a relative position between the seat surface of the seat ring and the wedge, the flow of the valve box A screw hole is provided on the inner surface of the passage, a groove portion is provided on the head of the seat ring, a screw portion that engages with a screw hole provided on the inner surface of the flow path of the valve box is provided on the body portion of the seat ring, Removably attach the seat ring to the valve box flow path. Only, it is characterized in that the removal or attachment of such relative flow path of the valve body the seat ring through the holes opened in the hood side of the valve box.
Further, the present invention is a valve box that is connected by welding to the upstream side pipe and the downstream side pipe through which the fluid flows and communicates with both pipes, and a bonnet attached to the upper part of the valve box, A valve box having a wedge provided at an end of a stem connected to a handle, and having a hole opening in the bonnet side in communication with the flow path of the valve box, facing the hole In an isolation valve that includes a seat ring having a seat surface that contacts the wedge of the stem at an end of the flow path of the valve ring, and isolates the flow path of the valve box by a relative position between the seat surface of the seat ring and the wedge. The seat ring is heated and cooled to be detachably attached to the flow path of the valve box, and is formed on the bonnet side of the valve box. Open to Characterized in that the removal or attachment of such relative flow path of the valve body the seat ring through the holes.

  Further, the present invention is a valve box that is connected by welding to the upstream side pipe and the downstream side pipe through which the fluid flows and communicates with both pipes, and a bonnet attached to the upper part of the valve box, A valve box having a wedge provided at an end portion of a stem connected to the handle, and having a hole portion opened to the bonnet side in communication with the flow path of the valve box, facing the hole portion An isolation valve that includes a seat ring having a seat surface that contacts the wedge of the stem at an end of the flow path of the valve ring, and isolates the flow path of the valve box by a relative position between the seat surface of the seat ring and the wedge. A claw provided with a claw groove on the inner surface of the flow path, a groove portion on the head of the seat ring, and an elastic body that engages with a claw groove provided on the inner surface of the flow path of the valve box on the body portion of the seat ring The seat ring is attached to and removed from the valve box flow path. Mounted on standing, characterized in that the removal or mounting as the seat ring through the opened hole in the bonnet side of the valve body relative to the flow path of the valve body.

The present invention includes a valve box that is connected to an upstream side pipe and a downstream side pipe through which fluid flows and is connected to each other by welding, and a bonnet attached to an upper part of the valve box, a handle The valve box has a wedge provided at the end of the stem connected to the valve box, and forms a hole in the valve box that opens to the bonnet side in communication with the flow path of the valve box, and faces the hole An isolation valve having a seat ring having a seat surface that contacts the wedge of the stem at the end of the flow path, and isolating the flow path of the valve box by a relative position between the seat surface of the seat ring and the wedge of the stem, A screw hole provided in the inner surface of the flow path of the valve box, a groove portion provided in the head of the seat ring, and a threaded portion that engages with a screw hole provided in the inner surface of the flow path of the valve box. And attach the seat ring to the flow path of the valve box. In replacing the isolation valve to freely attach features a method of replacing the isolation valve to replace the seat ring of the valve box with the following procedure.
(1) Apply an ice plug to the upstream piping of the valve box to block the fluid flowing through the piping,
(2) Fit the pin provided on the rod of the mounting / removal jig into the groove provided on the head of the seat ring,
(3) Rotate the rod of the mounting / removing jig to rotate the seat ring engaged with the pin and mounting / removing groove to remove the seat ring from the valve box flow path,
(4) Take out the seat ring removed from the flow path of the valve box to the outside of the valve box through the hole on the bonnet side of the valve box,
(5) Insert a healthy seat ring into the hole on the bonnet side of the valve box and rotate it with a mounting / removal jig, and install it in the screw hole formed in the flow path of the valve box on the body of the seat ring. Tighten the threaded part to attach the seat ring to the flow path of the valve box.
Further, the present invention is a valve box that is connected by welding to the upstream side pipe and the downstream side pipe through which the fluid flows and communicates with both pipes, and a bonnet attached to the upper part of the valve box, The valve having a wedge provided at an end of a stem connected to a handle, forming a hole in the valve box that communicates with a flow path of the valve box and that opens to a bonnet side, and faces the hole An isolation valve comprising a seat ring having a seat surface that contacts the wedge of the stem at an end of the flow path of the box, and isolating the flow path by a relative position between the seat surface of the seat ring and the wedge, wherein the seat ring is In the replacement method of the isolation valve, which is formed of a material having a large expansion rate by heating and a contraction rate by cooling compared to the material of the valve box, and this seat ring is heated and cooled and is detachably attached to the flow path of the valve box. Valve box The features of the method of replacing the isolation valve to be replaced by the following procedure Toringu.
(1) Apply an ice plug to the upstream piping of the valve box to block the fluid flowing through the piping,
(2) The valve box is cooled by a valve box coolant so that the outer diameter of the seat ring can be removed from the flow path of the valve box to be smaller than the inner diameter of the flow path,
(3) Take out the seat ring from the flow path of the valve box, take out the seat ring to the outside of the valve box through the hole on the bonnet side,
(4) Attach a healthy seat ring to the flow path of the valve box via the hole on the bonnet side of the valve box,
(5) The valve box is heated by a valve box heater and expanded until the outer diameter of the seat ring becomes a diameter that does not deviate from the flow path of the valve box. Install.

Further, the present invention is a valve box that is connected by welding to the upstream side pipe and the downstream side pipe through which the fluid flows and communicates with both pipes, and a bonnet attached to the upper part of the valve box, The valve having a wedge provided at an end of a stem connected to a handle, forming a hole in the valve box that communicates with a flow path of the valve box and that opens to a bonnet side, and faces the hole An isolation valve comprising a seat ring having a seat surface that contacts the wedge of the stem at an end of the flow path of the box, and isolating the flow path by a relative position between the seat surface of the seat ring and the wedge, wherein the seat ring is In the replacement method of the isolation valve, which is formed of a material having a large expansion rate by heating and a contraction rate by cooling compared to the material of the valve box, and this seat ring is heated and cooled and is detachably attached to the flow path of the valve box. Valve box The features of the method of replacing the isolation valve to be replaced by the following procedure Toringu.
(1) Apply an ice plug to the upstream piping of the valve box to block the fluid flowing through the piping,
(2) Fit the pin provided on the rod of the mounting / removal jig into the groove provided on the head of the seat ring,
(3) The rod of the mounting / removing jig is rotated to rotate the seat ring in which the pin and the mounting / removing groove are engaged, so that the claw groove of the valve box passage and the claw of the seat ring Remove the seat ring from the valve box flow path,
(4) Take out the seat ring removed from the flow path of the valve box to the outside of the valve box through the hole on the bonnet side of the valve box,
(5) Insert a healthy seat ring into the hole on the bonnet side of the valve box and rotate it using the mounting / removal jig, and install it in the claw groove formed in the flow path of the valve box on the body of the seat ring. The claw portion is engaged to attach the seat ring to the flow path of the valve box.

  According to the present invention, not only can the seat ring of the valve box constituting the isolation valve be exchanged without cutting the valve box and piping of the isolation valve, but also the inner dimensions of the valve box and the outer dimensions of the seat ring can be changed. It is possible to realize an isolation valve and a method for replacing the isolation valve that facilitates tolerance management and prevents the seat ring from being damaged at the edge of the flow path of the valve box when the seat ring is attached to the valve box.

The simplified diagram which shows the piping system of the control rod drive hydraulic system in a nuclear reactor. Sectional drawing which shows the detailed structure of the isolation valve which is 1st Example of this invention. Sectional drawing which shows the valve box of the isolation valve of 1st Example shown in FIG. Sectional drawing which shows the plug type seat ring with which the valve box of the isolation valve of 1st Example shown in FIG. 3 is mounted | worn. FIG. 4 is a schematic view of an attachment / detachment jig for detaching the plug-type seat ring shown in FIG. 3 from a valve box. Explanatory drawing which shows the state which attaches and detaches a plug type seat ring using the attachment / detachment jig | tool shown in FIG. 5 with respect to the valve box of the isolation valve of 1st Example shown in FIG. Sectional drawing which shows the valve box of the isolation valve which is 2nd Example of this invention. Sectional drawing which shows the plug type seat ring with which the valve box of the isolation valve of 2nd Example shown in FIG. 7 is mounted | worn. Explanatory drawing which shows the state which attaches / detaches the plug type seat ring shown in FIG. 8 to the valve box of the isolation valve of 2nd Example shown in FIG. Sectional drawing which shows the valve box of the isolation valve which is 3rd Example of this invention. Sectional drawing which shows the plug type seat ring with which the valve box of the isolation valve of 3rd Example shown in FIG. 10 is mounted | worn. Explanatory drawing which shows the state which attaches / detaches the plug type seat ring shown in FIG. 11 to the valve box of the isolation valve of 3rd Example shown in FIG. Sectional drawing of the valve case which shows the state which attached the plug type seat ring to the valve case of the isolation valve which is 4th Example of this invention. Sectional drawing which shows the valve box of 4th Example shown in FIG. FIG. 15 is a cross-sectional view showing a plug-type seat ring mounted on the valve box of the isolation valve of the fourth embodiment shown in FIG. 14. FIG. 16 is a schematic view of an attachment / detachment jig for detaching the plug-type seat ring shown in FIG. 15 from the valve box. Explanatory drawing which shows the motion of a jig | tool at the time of use of the attachment / detachment jig | tool which removes | removes the plug type seat ring shown in FIG. Explanatory drawing which shows the state which attaches or detaches a plug type seat ring using the attachment / detachment jig | tool shown in FIG. 16 with respect to the valve box of the isolation valve of 4th Example shown in FIG. Sectional drawing of the valve case which shows the state which attached the plug type seat ring to the valve case of the isolation valve which is 5th Example of invention. Sectional drawing which shows the valve box of 5th Example shown in FIG. Sectional drawing which shows the plug type seat ring with which the valve box of the isolation valve of 5th Example shown in FIG. 19 is mounted | worn. Explanatory drawing which shows the state which attaches / detaches a plug type seat ring with respect to the valve box of the isolation valve of 5th Example shown in FIG. 19 using an attachment / detachment jig | tool.

  The isolation valve which is an embodiment of the present invention, the isolation valve of the control rod drive hydraulic pressure control unit, and the replacement method of the isolation valve will be described below with reference to the drawings.

  The isolation valve according to the first embodiment of the present invention, the isolation valve of the control rod drive hydraulic pressure control unit, and the replacement method of the isolation valve will be described with reference to FIGS.

A control rod drive hydraulic pressure control unit 10 of a control rod drive mechanism (not shown) for driving a control rod of a nuclear reactor as shown in FIG. 1 includes a control rod drive mechanism (CRD, FMCRD) 30 is a device for controlling the water pressure of the control valve drive water supplied to 30. The piping 5 disposed in the control rod drive hydraulic pressure control unit 10 is provided with isolation valves 40 and 14, and other piping connected to the piping 5 is provided with isolation valves 13, 16 and 19, respectively. ing.
Further, the bar drive water pressure control unit 10 is provided with a nitrogen container 11 and an accumulator 12 storing scram supply water connected to the nitrogen container 11, and the accumulator 12 receives scram supply water stored therein. The pipe 5 is connected to be supplied. A scram valve 17 is provided between the isolation valve 40 of the pipe 5 and the accumulator 12. Reference numeral 15 denotes a check valve (check valve).
Next, the isolation valve used in the control rod drive water pressure control unit 10 will be described in detail below by taking the isolation valve 40 as an example.
As shown in FIG. 2, the isolation valve 40 of the present embodiment includes a valve box 41 in which a flow path 6 communicating with the pipe 5 is formed. The valve box 41 is connected to the upstream pipe 5. The bonnet 51 is attached to the upper portion of the valve box 41 with a hexagon bolt 52.
A bonnet-side hole 45 is formed in the center of the inside of the valve box 41, and a plug-type seat ring 70 is detachably attached to the end of the flow path 6 formed in the valve box 40.
On the other hand, the stem 62 for isolating the fluid is provided with a wedge 61 at the tip, and is screwed into the bonnet 51 so as to be movable up and down. A sheet surface is formed between the wedge 61 and the plug-type seat ring 70 so that the fluid is It has a structure to isolate. A handle 63 is fixed to the stem 62 by a washer 64 and a nut 65 so that it can be easily rotated.
Seal members 53 and 54 are installed between the stem 62 and the bonnet 51, and a seal member 46 is installed on the joint surface between the bonnet 51 and the valve box 41 to prevent fluid leakage. .
As shown in FIGS. 3 and 4, a plug type seat ring 70 is provided at the end of the flow path 6 facing the hole 45 on the bonnet side among the flow paths 6 of the valve box 41 constituting the isolation valve 40. It is detachably attached.
The plug-type seat ring 70 includes a screw portion 71 and a seat member 73 on the outer peripheral side of the body portion, a seat surface at the tip of the head, and a mounting / removal groove 72 on the outer peripheral side of the head. It is a configuration.

  The plug-type seat ring 70 is a seat ring 70 that can be attached to and detached from the valve box 41 constituting the isolation valve 40.

  A counterbore 44 is provided at the end of the flow path 6 of the valve box 41 so that the plug-type seat ring 70 can be attached to and detached from the flow path 6 of the valve box 41. Is provided with a screw hole 42. Then, the plug-type seat ring 70 is carried in through the bonnet side hole 45 of the valve box 41, and the plug-type seat ring 70 is attached and attached to the end of the flow path 6 of the valve box 41.

  The screw hole 42 of the valve box 41 is connected to a pipe connection hole 43 connected to the flow path 6 of the valve box 41 with a mounting / removing jig 80 (described later) plug-type seat ring. The bonnet 51 is slightly inclined from the horizontal so that the engagement with the 70 becomes easy. The attachment / detachment jig 80 includes a rod 84, a holder 83 provided at the tip of the rod 84 via a universal joint 85, and a pin 82 provided on the holder 83.

  When the screw hole 42 of the valve box 41 is provided with an inclination, the workability of taking out the plug-type seat ring 70 to the outside of the valve box 41 through the hole 45 on the bonnet side is improved.

When the plug-type seat ring 70 detachably attached to the valve box 41 of the isolation valve 40 is damaged due to any factor, the plug-type seat ring is obtained based on the following procedure (1) to procedure (6). 70 will be replaced. A method for replacing the plug-type seat ring 70 will be described below with reference to FIGS.
In the valve box 41 of the isolation valve 40 of the present embodiment shown in FIGS.
Procedure (1): The upstream pipe 5 connected to the valve box 41 of the isolation valve 40 is cooled using an ice plug method to block the fluid flowing through the upstream pipe 5. The ice plug method is a construction technology that blocks the flow of fluid in the flow path by freezing liquid in the piping with liquid nitrogen etc. to form an ice plug when repairing a valve that cannot isolate the system. It is.

  Step (2): Using the mounting / removal jig 80 shown in FIG. 5, the bonnet side hole formed in the central portion of the valve box 41 as shown in FIG. 45, the pin 82 is engaged with a mounting / removal groove 72 provided on the outer peripheral side of the plug-type seat ring 70.

  Procedure (3): By rotating the rod 84 of the mounting / removal jig 80, the holder 83 engaged with the mounting / removal groove 72 of the plug-type seat ring 70 is rotated via the pin 82, and the plug-type The screw part 71 of the seat ring 70 is rotated, and the plug type seat ring 70 is removed from the screw hole 42 formed in the flow path 6 of the valve box 41.

  Procedure (4): The plug type seat ring 70 removed from the screw hole 42 formed in the flow path 6 of the valve box 41 is taken out to the outside of the valve box 41 through the hole 45 on the bonnet side of the valve box 41.

  Step (5): Next, the healthy plug type seat ring 70 is inserted into the valve box 41 from the hole 45 on the bonnet side of the valve box 41, and the mounting / removing jig 80 is operated to operate the plug type sheet. The screw part 71 of the ring 70 is rotated in the reverse direction, and the plug type seat ring 70 is attached to the screw hole 42 formed in the flow path 6 of the valve box 41.

  Procedure (6): Using the mounting / removal jig 80, the screw portion 71 of the plug-type seat ring 70 is tightened into the screw hole 42 of the flow path 6 of the valve box 41, or in the case of the isolation valve 41 having a large diameter, If tightening is possible, the threaded portion 71 of the plug-type seat ring 70 is tightened into the screw hole 42 of the flow path 6 of the valve box 41 by hand tightening without using the mounting / removal jig 80, thereby 70 is firmly attached to the flow path 6 of the valve box 41.

  According to this embodiment, not only can the seat ring of the valve box constituting the isolation valve be exchanged without cutting the valve box and piping of the isolation valve, but also the inner dimensions of the valve box and the outer dimensions of the seat ring. Therefore, when the seat ring is attached to the valve box, the isolation valve and the isolation valve replacement method for preventing the seat ring from being damaged at the edge of the flow path of the valve box can be realized.

  The isolation valve, the isolation valve of the control rod drive hydraulic control unit and the method for replacing the isolation valve according to the second embodiment of the present invention will be described with reference to FIGS.

  Since this embodiment has the same basic structure as the isolation valve of the first embodiment described above, the description of the configuration common to both is omitted, and the configuration of the present embodiment is different from the first embodiment. Only will be described below.

  7 to 9, in the isolation valve 40 of the present embodiment, the expansion rate due to heating is large as the plug-type seat ring 120 attached to the distal end portion of the flow path 6 of the valve box 131 constituting the isolation valve 40, and due to cooling. It is made of a metal material having a large shrinkage rate, and includes a seal member 73 on the outer peripheral side of the trunk, a seat surface at the tip of the head, and a mounting / removal groove 72 on the outer periphery of the head. A detachable plug-type seat ring 120 is provided.

  The plug-type seat ring 120 has a higher thermal expansion coefficient than that of the valve box 131, and the plug-type seat ring 120 is connected to the flow path 6 of the valve box 131 even with respect to the minimum operating temperature of the device. The material is such that expansion is maintained to such an extent that it does not fall out of the bore hole 134 provided at the end.

  For example, the plug-type seat ring 120 is made of an aluminum alloy (A3000 series), and the valve box 131 is made of stainless steel (SUS304 or the like) having a smaller coefficient of thermal expansion than the aluminum alloy.

  Next, a counterbore 134 is provided at the tip of the flow path 6 in the flow path 6 of the valve box 131 so that the plug-type seat ring 120 can be attached and detached. A pipe connection hole 133 having a diameter that does not easily come off when the pipe expands is provided.

  The connection hole 133 of the valve box 131 is provided horizontally with respect to the central axis of the flow path 6 of the valve box 131, or an attachment / detachment jig 170 described later can be easily engaged with the plug type seat ring 120. In such a way, it is provided with a slight inclination toward the bonnet side with respect to the central axis of the flow path 6.

If the plug-type seat ring 120 attached to the valve box 131 of the isolation valve 40 is damaged due to any factor, the plug-type seat ring 120 is replaced based on the following procedure (1) to procedure (5). However, a method for replacing the plug-type seat ring 120 will be described next with reference to FIGS.
In the valve case 131 of the isolation valve 40 of the present embodiment shown in FIGS.
Procedure (1): The upstream pipe 91 connected to the valve box 131 of the isolation valve 40 is cooled using an ice plug method to block the fluid flowing through the upstream pipe 91.

  Procedure (2): The valve box 131 is cooled by the valve box coolant 93 and contracted until the plug outer diameter of the plug-type seat ring 120 becomes smaller than the inner diameter of the flow path 6 of the valve box 131 and becomes a removable diameter. Let

  Procedure (3): The plug-type seat ring 120 is removed from the flow path 6 of the valve box 131 using manual or mounting / removal jigs, and the plug-type seat ring 120 is passed through the hole 135 on the bonnet side of the valve box 131. And take it out of the valve box 131.

  Step (4): Next, the healthy plug type seat ring 120 is inserted into the inside of the valve box 131 from the hole 135 on the bonnet side of the valve box 131, and the plug type seat ring 120 is manually or using an attaching / detaching jig. Is attached to the flow path 6 of the valve box 131.

  Step (5): The valve box 131 is heated by the valve box heater 94 to expand so that the plug outer diameter of the plug-type seat ring 120 does not come off from the flow path hole 6 of the valve box 131. Is firmly attached to the flow path 6 of the valve box 131, so that the plug-type seat ring 120 is firmly attached to the flow path 6 of the valve box 131.

  According to this embodiment, not only can the seat ring of the valve box constituting the isolation valve be exchanged without cutting the valve box and piping of the isolation valve, but also the inner dimensions of the valve box and the outer dimensions of the seat ring. Therefore, when the seat ring is attached to the valve box, the isolation valve and the isolation valve replacement method for preventing the seat ring from being damaged at the edge of the flow path of the valve box can be realized.

  An isolation valve used in a control rod drive hydraulic control unit according to a third embodiment of the present invention and an isolation valve replacement method will be described with reference to FIGS.

  Since this embodiment has the same basic structure as the isolation valve of the first embodiment described above, the description of the configuration common to both is omitted, and the configuration of the present embodiment is different from the first embodiment. Only will be described below.

  10 to 12, in the isolation valve 40 of the present embodiment, as the plug-type seat ring 140 attached to the distal end portion of the flow path 6 of the valve box 111 constituting the isolation valve 40, the expansion coefficient due to heating is large, and due to cooling. It is manufactured using a metal material having a high shrinkage rate, and includes a seal member 143 on the outer peripheral side of the body, a seat surface at the tip of the head, and a mounting / removal groove 142 on the outer periphery of the head. A detachable plug type seat ring 140 is provided.

  The plug-type seat ring 140 has a coefficient of thermal expansion smaller than that of the valve box 111, and the plug-type seat ring 140 is connected to the flow path 6 of the valve box 111 even at the minimum operating temperature of the device. It is assumed that the material can be expanded so that it does not fall off from the search hole 114 provided at the end.

  For example, the plug-type seat ring 140 is made of stainless steel (SUS304 or the like), and the valve box 111 is made of an aluminum alloy (A3000 series) having a thermal expansion coefficient larger than that of stainless steel.

Next, a counterbore 114 is provided at the tip of the flow path 6 in the flow path 6 of the valve box 111 so that the plug-type seat ring 140 can be attached and detached. A pipe connection hole 113 having a diameter that does not easily come off when the pipe expands is provided.
The pipe connection hole 113 of the valve box 111 is provided horizontally with respect to the central axis of the flow path 6 of the valve box 111, or an attachment / detachment jig 170 described later can be easily engaged with the plug type seat ring 140. In such a manner, it is slightly inclined toward the bonnet side with respect to the central axis of the flow path 6.

When the plug-type seat ring 140 attached to the valve box 111 of the isolation valve 40 is damaged due to some factor, the plug-type seat ring 140 is replaced based on the following procedure (1) to procedure (5). However, a method for replacing the plug-type seat ring 140 will be described next with reference to FIGS.
In the valve box 111 of the isolation valve 40 of the present embodiment shown in FIGS.
Procedure (1): The upstream pipe 91 connected to the valve box 111 of the isolation valve 40 is cooled using an ice plug method to block the fluid flowing through the upstream pipe 91.

  Procedure (2): The plug type seat ring 140 attached to the flow path 6 of the valve box 111 is directly cooled by the plug coolant 95, and the plug outer diameter of the plug type seat ring 140 is the inner diameter of the flow path 6 of the valve box 111. Shrink until it becomes smaller and has a removable diameter.

  Step (3): The plug-type seat ring 140 is removed from the flow path 6 of the valve box 111 using manual or mounting / removal jigs, and the plug-type seat ring 140 is passed through the bonnet side hole 115 of the valve box 111. And take it out of the valve box 111.

  Step (4): Next, the healthy plug type seat ring 140 is inserted into the inside of the valve box 111 from the hole 115 on the bonnet side of the valve box 111, and the plug type seat ring 140 is manually or using an attaching / detaching jig. Is attached to the flow path 6 of the valve box 111.

  Step (5): The plug type seat ring 140 attached to the flow path 6 of the valve box 111 is directly heated by the plug heater 96 so that the plug outer diameter of the plug type seat ring 140 is disengaged from the flow path hole 6 of the valve box 111. The plug type seat ring 140 is firmly attached to the flow path 6 of the valve box 111 by inflating the plug type seat ring 140 to the flow path 6 of the valve box 111.

  According to this embodiment, not only can the seat ring of the valve box constituting the isolation valve be exchanged without cutting the valve box and piping of the isolation valve, but also the inner dimensions of the valve box and the outer dimensions of the seat ring. Therefore, when the seat ring is attached to the valve box, the isolation valve and the isolation valve replacement method for preventing the seat ring from being damaged at the edge of the flow path of the valve box can be realized.

  An isolation valve used in a control rod drive hydraulic control unit according to a fourth embodiment of the present invention and an isolation valve replacement method will be described with reference to FIGS.

Since the basic structure of this embodiment is the same as that of the first embodiment described above, the description of the structure common to both is omitted, and only the structure of this embodiment that is different from the first embodiment is described below. Explained.
13 to 18, in the isolation valve 40 of the present embodiment, a plug-type seat ring 160 is detachably attached to the distal end portion of the flow path 6 of the valve box 151 constituting the isolation valve 40.
As shown in detail in FIG. 15, the plug-type seat ring 160 is provided with a claw portion composed of a claw 161, a pin 162 and an elastic body 163 on the outer peripheral side of the body portion, The seat surface has a configuration in which a groove 164 for attachment / detachment is provided on the outer peripheral side of the head.

  In order to attach the plug type seat ring 160 to the flow path 6 of the valve box 151, a claw fixing groove 152 is provided on the inner surface of the flow path 6 of the valve box 151, and the claw fixing groove 152 is formed by the elastic body 163. The plug-type seat ring 160 opened in the radially outward direction is configured to be hooked and attached.

  The flow path 6 of the valve box 151 is relative to the central axis of the flow path 6 of the valve box 151 so that the engagement with the plug-type seat ring 160 is facilitated by using an attachment / detachment jig 170 described later. The bonnet side is slightly inclined.

  As shown in FIG. 16, the attachment / removal jig 170 for the plug-type seat ring 160 includes a rod 171, a holder 176 provided at the tip of the rod 171, a guide 173 attached to the holder 176, and a positioning pin. 172, a shaft 174, and a gear 175 attached to the shaft 174. By rotating the rod 171, the holder 176 can be developed and stored via the shaft 174 and the gear 175.

  The plug-type seat ring 160 causes the claw 161 of the plug-type seat ring 160 to open radially outward by the elastic force of the elastic body 163, and the claw 161 is inserted into the claw fixing groove 152 of the flow path 6 of the valve box 151. The plug-type seat ring 160 is attached to the flow path 6 of the valve box 151 by being hooked and not easily detached.

If the plug-type seat ring 160 that is detachably attached to the valve box 151 of the isolation valve 40 is damaged due to any factor, the plug-type seat ring is obtained based on the following procedure (1) to procedure (5). The replacement method of the plug type seat ring 160 will be described below with reference to FIGS.
In the valve box 151 of the isolation valve 40 of the present embodiment shown in FIGS.
Procedure (1): The upstream pipe 5 connected to the valve box 151 of the isolation valve 40 is cooled using an ice plug method to block the fluid flowing through the upstream pipe 5.

  Step (2): Using the mounting / removing jig 170 shown in FIG. 16, the mounting / removing jig 170 is inserted into the hole of the flow path 6 of the valve box 151 as shown in FIG. The holder 176 is expanded by rotating the rod 171 of the removal jig 170, and the claw 161 holding the plug type seat ring 160 is removed from the claw fixing groove 152 of the flow path 6 of the valve box 151.

  Procedure (3): The attachment / removal jig 170 is pulled out as it is, and the plug-type seat ring 160 is taken out from the hole 155 on the bonnet side of the valve box 151.

  Step (4): Next, a healthy plug type seat ring 160 is inserted into the valve box 151 through the hole 155 on the bonnet side of the valve box 151 using the mounting / removing jig 170, and the mounting / removing jig is installed. The plug type seat ring 160 is attached to the flow path 6 of the valve box 151 using 170.

  Step (5): Next, as shown in FIGS. 17 and 18, the rod 171 of the mounting / removal jig 170 is rotated to house the holder 176, and the claw 161 of the plug-type seat ring 160 is moved radially outward. The plug type seat ring 160 is firmly attached to the flow path 6 of the valve box 151 by opening it in the direction and hooking it in the claw fixing groove 152 of the valve box 151.

  According to this embodiment, not only can the seat ring of the valve box constituting the isolation valve be exchanged without cutting the valve box and piping of the isolation valve, but also the inner dimensions of the valve box and the outer dimensions of the seat ring. Therefore, when the seat ring is attached to the valve box, the isolation valve and the isolation valve replacement method for preventing the seat ring from being damaged at the edge of the flow path of the valve box can be realized.

  An isolation valve used in a control rod drive hydraulic control unit according to a fifth embodiment of the present invention and an isolation valve replacement method will be described with reference to FIGS.

Since the basic structure of this embodiment is the same as that of the fourth embodiment described above, description of the structure common to both is omitted, and only the structure of this embodiment that is different from the first embodiment is described below. Explained.
19 to 22, in the isolation valve 40 of the present embodiment, a plug-type seat ring 190 is detachably attached to the distal end portion of the flow path 6 of the valve box 181 constituting the isolation valve 40.
As shown in detail in FIG. 21, the plug-type seat ring 190 is provided with a claw portion including a claw 191, a pin 192 and an elastic body 193 on the outer peripheral side of the body portion, The seat surface has a configuration in which a groove 194 for attachment / detachment is provided on the outer peripheral side of the head.

  In order to attach the plug type seat ring 190 to the flow path 6 of the valve box 181, a claw fixing groove 182 is provided on the inner surface of the flow path 6 of the valve box 181, and the claw fixing groove 182 is formed by an elastic body 163. The claw 191 of the plug-type seat ring 190 opened radially outward is caught and attached.

  Note that an end counterbore 184 of the flow path 6 of the valve box 181 is provided, and a pipe connection hole 183 that is the flow path 6 is provided horizontally with respect to the central axis of the flow path 6.

  The plug-type seat ring 190 opens the claw 191 of the plug-type seat ring 190 radially outward by the elastic force of the elastic body 193, and the claw 191 is inserted into the claw fixing groove 182 of the flow path 6 of the valve box 181. The plug-type seat ring 190 is attached to the flow path 6 of the valve box 181 by being hooked and not easily detached.

When the plug-type seat ring 190 attached to the valve box 181 constituting the isolation valve 40 is damaged due to any factor, the plug-type seat ring 190 is based on the following procedure (1) to procedure (5). Next, a method for replacing the plug-type seat ring 190 will be described with reference to FIGS. In that case, the attachment / detachment jig 170 shown in FIG. 16 may be used.
In the valve case 181 of the isolation valve 40 of this embodiment shown in FIGS. 19 to 22,
Procedure (1): The upstream pipe 5 connected to the valve box 181 of the isolation valve 40 is cooled using an ice plug method to block the fluid flowing through the upstream pipe 5.

  Procedure (2): Using the attachment / removal jig 170 shown in FIG. 16, the attachment / removal jig 170 is inserted into the hole 185 on the bonnet side of the valve box 181 to insert the attachment / removal jig 170. The rod 171 is rotated to unfold the holder 176, and the plug-type seat ring 190 is rotated so that the claw 191 provided on the plug-type seat ring 190 is formed in the flow path 6 of the valve box 181. Remove from 152.

  Procedure (3): With the plug-type seat ring 190 held, the mounting / removal jig 170 is pulled out, and the plug-type seat ring 190 is taken out of the valve box 181 from the bonnet side hole 185 of the valve box 181. .

  Procedure (4): Next, a healthy plug type seat ring 190 is inserted into the inside of the valve box 181 from the bonnet side hole 185 of the valve box 181 using the mounting / removing jig 170, and the mounting / removing jig is installed. The plug type seat ring 190 is attached to the flow path 6 of the valve box 181 using 170.

  Step (5): Next, as shown in FIG. 22, the rod 171 of the mounting / removal jig 170 is rotated to store the holder 176, and the claw 191 of the plug-type seat ring 190 is opened radially outward. The plug type seat ring 190 is firmly attached to the flow path 6 of the valve box 181 by being hooked in the claw fixing groove 182 of the valve box 181.

  According to this embodiment, not only can the seat ring of the valve box constituting the isolation valve be exchanged without cutting the valve box and piping of the isolation valve, but also the inner dimensions of the valve box and the outer dimensions of the seat ring. Therefore, when the seat ring is attached to the valve box, the isolation valve and the isolation valve replacement method for preventing the seat ring from being damaged at the edge of the flow path of the valve box can be realized.

  The present invention is applicable to an isolation valve used in a control rod drive hydraulic pressure control unit of a control rod drive hydraulic device that supplies control rod drive water to a control rod drive mechanism of a nuclear reactor, and an isolation valve replacement method.

  5: piping, 6: flow path, 10: control rod drive water pressure control unit, 11: nitrogen container, 12: accumulator, 13, 14, 16, 18, 19: isolation valve, 15: check valve (check valve), 17: Scram valve, 20: Pressure vessel, 30: Control rod drive mechanism (CRD, FMCRD), 40: Isolation valve, 41: Valve box, 42: Screw hole, 43: Pipe connection hole, 44: Counterbore hole, 45 : Bonnet side hole, 46: Seal member, 47: Stem support, 51: Bonnet, 52: Hex bolt, 53, 54: Seal member, 61: Wedge, 62: Stem, 63: Handle, 64: Washer, 65: Nut, 70: Plug type seat ring, 71: Screw part, 72: Mounting / removing groove, 73: Seal member, 80: Mounting / removing jig, 81: Holder, 82: Pin, 83: Universal, Joint, 4: Rod, 91: Piping, 92: Coolant (for ice plug), 93: Coolant for valve box, 94: Heater for valve box, 95: Coolant for plug, 96: Heater for plug, 101: Valve box 103: Piping connection hole, 104: Counterbore hole, 105: Bonnet side hole, 111: Valve box, 113: Piping connection hole, 114: Counterbore hole, 115: Bonnet side hole, 120: Plug type seat ring 122: Mounting / removal groove 123: Seal member 131: Valve box 133: Pipe connection hole 134: Counterbore hole 135: Hole on the bonnet side 140: Plug type seat ring 142: Mounting / removal Groove, 143: Seal member, 151: Valve box, 152: Claw fixing groove, 153: Piping connection hole, 154: Counterbore hole, 155: Hole on the bonnet side, 160: Plug type seat ring with claw, 161: Claw , 16 : Pin, 163: Elastic body, 164: Mounting / removal groove, 165: Seal member, 170: Mounting / removing jig, 171: Rod, 172: Positioning pin, 173: Guide, 174: Shaft, 175: Gear 176: Holder, 181: Valve box, 182: Claw fixing groove, 183: Piping connection hole, 184: Counterbore hole, 185: Hole on the bonnet side, 190: Plug type seat ring with claw, 191: Claw, 192 : Pin, 193: elastic body, 194: mounting / removal groove, 195: seal member.

Claims (8)

A valve box that is connected to the upstream side pipe and the downstream side pipe through which the fluid flows by welding and has a flow path communicating with both pipes formed therein, a bonnet attached to the upper part of the valve box, and a stem connected to the handle An opening provided on the bonnet side in communication with the flow path of the valve box, and an end of the flow path of the valve box facing the hole In an isolation valve that includes a seat ring having a seat surface that comes into contact with the wedge of the stem in the part, and isolates the flow path of the valve box by the relative position between the seat surface of the seat ring and the wedge,
A screw hole provided in the inner surface of the flow path of the valve box, a groove portion provided in the head of the seat ring, and a threaded portion that engages with a screw hole provided in the inner surface of the flow path of the valve box. The seat ring is detachably attached to the flow path of the valve box, and the seat ring is removed or attached to the flow path of the valve box through a hole opened on the bonnet side of the valve box. Isolation valve characterized by. The isolation valve according to claim 1,
The isolation valve according to claim 1, wherein the flow path of the valve box is formed such that the central axis of the flow path is inclined toward the bonnet side with respect to the horizontal. A valve box that is connected to the upstream side pipe and the downstream side pipe through which the fluid flows by welding and has a flow path communicating with both pipes formed therein, a bonnet attached to the upper part of the valve box, and a stem connected to the handle An opening provided on the bonnet side in communication with the flow path of the valve box, and an end of the flow path of the valve box facing the hole In an isolation valve that includes a seat ring having a seat surface that comes into contact with the wedge of the stem in the part, and isolates the flow path of the valve box by the relative position between the seat surface of the seat ring and the wedge,
The seat ring is formed of a material having a larger expansion rate by heating and a smaller shrinkage rate by cooling than the material of the valve box, and the seat ring is heated and cooled to be detachably attached to the flow path of the valve box. An isolation valve characterized in that the seat ring is removed from or attached to the flow path of the valve box through a hole opened on the bonnet side of the box. A valve box that is connected to the upstream side pipe and the downstream side pipe through which the fluid flows by welding and has a flow path communicating with both pipes formed therein, a bonnet attached to the upper part of the valve box, and a stem connected to the handle A hole provided on the bonnet side in communication with the flow path of the valve box is formed in the valve box, and the end of the flow path of the valve box facing the hole In an isolation valve that includes a seat ring having a seat surface that comes into contact with the wedge of the stem in the part, and isolates the flow path of the valve box by the relative position between the seat surface of the seat ring and the wedge,
An elastic body provided with a claw groove on the inner surface of the flow passage of the valve box, a groove portion on the head of the seat ring, and engaged with a claw groove provided on the inner surface of the flow passage of the valve box on the body portion of the seat ring The seat ring is removably attached to the flow path of the valve box, and the seat ring is removed from or attached to the flow path of the valve box through a hole opened on the bonnet side of the valve box. An isolation valve characterized by the above. The isolation valve according to claim 4,
The isolation valve is an isolation valve used in a control rod drive water pressure control unit. A valve box that is connected to the upstream side pipe and the downstream side pipe through which the fluid flows by welding and has a flow passage communicating with both pipes formed therein, a bonnet attached to the upper part of the valve box, and a stem connected to the handle The valve box has a wedge that communicates with the flow path of the valve box and opens to the bonnet side, and the flow path of the valve box that faces the hole is formed. An isolation valve having a seat ring having a seat surface abutting against the wedge of the stem at an end, and isolating the flow path of the valve box by a relative position between the seat surface of the seat ring and the wedge of the stem, A screw hole is provided on the inner surface of the flow path, a groove is provided on the head of the seat ring, and a thread portion that engages with a screw hole provided on the inner surface of the flow path of the valve box is provided on the body of the seat ring. The seat ring is detachably attached to the flow path of the valve box. In exchange method of isolation valves to give,
Replacing the isolation valve by replacing the valve ring seat ring by the following procedure.
(1) Apply an ice plug to the upstream piping of the valve box to block the fluid flowing through the piping,
(2) Fit the pin provided on the rod of the mounting / removal jig into the groove provided on the head of the seat ring,
(3) Rotate the rod of the mounting / removing jig to rotate the seat ring engaged with the pin and mounting / removing groove to remove the seat ring from the valve box flow path,
(4) Take out the seat ring removed from the flow path of the valve box to the outside of the valve box through the hole on the bonnet side of the valve box,
(5) Insert a healthy seat ring into the hole on the bonnet side of the valve box and rotate it with a mounting / removal jig, and install it in the screw hole formed in the flow path of the valve box on the body of the seat ring. Tighten the threaded part to attach the seat ring to the flow path of the valve box. A valve box that is connected to the upstream side pipe and the downstream side pipe through which the fluid flows by welding and has a flow path communicating with both pipes formed therein, a bonnet attached to the upper part of the valve box, and a stem connected to the handle The valve box has a wedge that communicates with the flow path of the valve box and opens to the bonnet side, and the flow path of the valve box that faces the hole is formed. An isolation valve that includes a seat ring having a seat surface that contacts the wedge of the stem at an end, and isolates the flow path by a relative position between the seat surface of the seat ring and the wedge,
The seat ring is formed of a material having a higher expansion rate by heating and a lower shrinkage rate by cooling than the material of the valve box, and the seat ring is heated and cooled to attach and detachably attach to the flow path of the valve box. In the replacement method, the isolation valve replacement method in which the valve ring seat ring is replaced by the following procedure.
(1) Apply an ice plug to the upstream piping of the valve box to block the fluid flowing through the piping,
(2) The valve box is cooled by a valve box coolant so that the outer diameter of the seat ring can be removed from the flow path of the valve box to be smaller than the inner diameter of the flow path,
(3) Take out the seat ring from the flow path of the valve box, take out the seat ring to the outside of the valve box through the hole on the bonnet side,
(4) Attach a healthy seat ring to the flow path of the valve box via the hole on the bonnet side of the valve box,
(5) The valve box is heated by a valve box heater and expanded until the outer diameter of the seat ring becomes a diameter that does not deviate from the flow path of the valve box. Install. A valve box that is connected to the upstream side pipe and the downstream side pipe through which the fluid flows by welding and has a flow path communicating with both pipes formed therein, a bonnet attached to the upper part of the valve box, and a stem connected to the handle The valve box has a wedge that communicates with the flow path of the valve box and opens to the bonnet side, and the flow path of the valve box that faces the hole is formed. An isolation valve that includes a seat ring having a seat surface that contacts the wedge of the stem at an end, and isolates the flow path by a relative position between the seat surface of the seat ring and the wedge,
The seat ring is formed of a material having a higher expansion rate by heating and a lower shrinkage rate by cooling than the material of the valve box, and the seat ring is heated and cooled to attach and detachably attach to the flow path of the valve box. In the exchange method,
Replacing the isolation valve by replacing the valve ring seat ring by the following procedure.
(1) Apply an ice plug to the upstream piping of the valve box to block the fluid flowing through the piping,
(2) Fit the pin provided on the rod of the mounting / removal jig into the groove provided on the head of the seat ring,
(3) The rod of the mounting / removing jig is rotated to rotate the seat ring in which the pin and the mounting / removing groove are engaged, so that the claw groove of the valve box passage and the claw of the seat ring Remove the seat ring from the valve box flow path,
(4) Take out the seat ring removed from the flow path of the valve box to the outside of the valve box through the hole on the bonnet side of the valve box,
(5) Insert a healthy seat ring into the hole on the bonnet side of the valve box and rotate it using the mounting / removal jig, and install it in the claw groove formed in the flow path of the valve box on the body of the seat ring. The claw portion is engaged to attach the seat ring to the flow path of the valve box.

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