JP2014029195A - Method of removing valve cover of gate valve and gate valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of removing valve cover of gate valve which facilitates removal operation of valve cover provided with a valve body and a valve rod in non-cutoff water state while reducing a construction cost and, further, reliably preventing water leakage from a bolt insertion hole of a valve box.SOLUTION: A method of removing a valve cover 4 of a gate valve includes: a process of attaching an annular attachment frame A which surrounds a part of the valve cover 4 to a first connection part 2D of the valve box 2; a process of pushing and fastening a second connection part 4A of the valve cover 4 to the first connection part 2D of the valve box 2 by means of a pushing means B; a process of removing bolt and nut which fastens and connects both connection parts 2D, 4A; a process of performing cutoff of a bolt insertion hole of the first connection part 2D in the pressing state from the lower surface side by means of a pushing cutoff means C equipped on a reactive force receiving part D of the valve box 2; a process of attaching an operation housing H provided with an operating opening and closing valve V2 and an elevation conveying means E to an annular attachment frame A; a process of releasing pushing fastening of the pushing means B, taking out the valve cover 4 into the operation housing H by means of the elevation conveying means E and performing valve-closing operation of the operating opening and closing valve V2; and a process of removing the valve cover 4 in the operation housing H.

Description

  The present invention is the gate valve connected to the fluid piping system, when the valve body having a short life compared to the valve box reaches the set durability years, or when the valve body malfunctions, The present invention relates to a valve cover removal method for a gate valve that removes a valve cover including a valve body and a valve stem from a valve box in an indefinite water state, and an improved technique for a gate valve used therefor.

  As a gate valve connected to a fluid piping system, generally, a flange as a first connecting portion formed in a valve body mounting opening of a valve box and a flange as a second connecting portion formed in a valve lid A gate valve is used in which bolts and nuts are tightened and fixed in a watertight state.

As a valve lid removal method using such a general gate valve,
The lower housing of the divided structure that surrounds substantially the entire gate valve in a state including a part of both the fluid pipes in both the upstream and downstream fluid pipes connected to the valve box of the gate valve in a watertight state. Installation process,
A step of maintaining the watertight state between both flanges by sandwiching and fixing the flange of the valve box and the flange of the valve lid from the outside by a flange holding device provided in the lower housing;
Removing the bolts and nuts that fasten and fix the flange of the valve box and the flange of the valve lid;
A step of connecting a lower end portion of a lower divided lifting shaft portion among a plurality of divided lifting shaft portions constituting a lifting shaft of a lifting and lowering conveying device equipped in an upper housing to an upper end portion of a valve stem of a gate valve;
Fixing the lower flange of the work on / off valve to the flange of the upper opening of the lower housing in a watertight state with bolts and nuts;
The upper part of the lifting / lowering shaft part of the lifting / lowering conveying device provided in the upper housing is connected to the lower part of the lifting / lowering shaft part connected to the valve rod of the gate valve and the upper flange of the work on / off valve. A process of fixing and connecting the lower flange of the upper housing in a watertight state with bolts and nuts,
After releasing the pinching between the flange of the valve box and the flange of the valve lid by the flange holding device, the lifting shaft of the lifting and lowering conveying device is lifted so that the valve lid with the valve body and the valve stem is placed in the storage space of the upper housing Taking out the inside and closing the work on-off valve,
Removing the valve lid taken out in the storage space of the upper housing;
A valve lid removal method having the above steps has been proposed (see, for example, Patent Document 1).

JP2007-177945

  The conventional method for removing the valve lid of the gate valve requires a lower housing having a large divided structure for enclosing substantially the entire gate valve in a state including a part of both fluid pipes. Since the excavation volume also becomes large, the construction becomes large and there is a disadvantage that the construction cost increases.

  The present invention has been made in view of the above-described actual situation, and the main problem is that the removal of the valve lid provided with the valve body and the valve stem in an indefinite water state is performed while reducing the construction cost. The valve cover removal method of the gate valve that can be efficiently and easily performed in a state that reliably prevents water leakage from the bolt insertion hole formed in the first connection part of the valve box, and the efficiency of the removal work It is in providing a gate valve that contributes to facilitation.

A first characteristic configuration according to the present invention includes a valve box connected to a fluid piping system, and a second connection fixedly connected by bolts and nuts to a first connection part provided in a valve body mounting port of the valve box. Of the gate valve, comprising: a valve lid provided with a portion; and a valve body detachably mounted from a valve body mounting port of the valve box via a valve rod penetrating the valve lid. And a valve lid removal method for a gate valve that removes the valve lid with a valve stem from the valve box in an unrestricted state of water,
Attaching an annular mounting frame that surrounds at least a part of the valve lid including the second connecting portion to the first connecting portion of the valve box in a watertight state;
A step of pressing and fixing the second connecting portion of the valve lid against the first connecting portion of the valve box in a watertight state by a pressing means provided on the annular mounting frame;
Removing the bolts and nuts fixedly connecting the first and second connecting parts;
A step of water-stopping the bolt insertion hole of the first connecting portion in a pressed state from the lower surface side by means of a pressure-stopping device provided in the reaction force receiving portion provided in the valve box;
A step of attaching to the annular mounting frame a work housing provided with a work on-off valve and a lift conveying means coupled to the valve lid;
Releasing the pressing and fixing of the presser means, and taking out the valve lid into the storage space in the work housing by the lifting and lowering transport means, and then closing the work on-off valve; and
Removing the valve lid taken out in the storage space in the working housing;
It is in the point equipped with.

  According to the above configuration, when removing a valve lid provided with a valve body that has reached the set endurance life or a valve body that has malfunctioned, first, an annular mounting frame is watertight on the first connecting portion of the valve box. Since the work housing provided with the lifting and lowering conveying means connected to the valve lid and the valve lid is attached to the annular mounting frame in a watertight state, the gate valve of the gate valve is included in a state including a part of both fluid pipes. Compared to the conventional method using a lower housing with a divided structure that encloses substantially the whole, the housing required for the lower side of the gate valve and part of both fluid pipes can be reduced, and accordingly Thus, the excavation volume of the work pit can be reduced.

  In addition, in the process before mounting the work housing, the second connecting portion of the valve lid is watertight with respect to the first connecting portion of the valve box by the holding means of the annular mounting frame attached to the first connecting portion of the valve box. Since the bolts and nuts that fixably connect the first and second connecting parts in this state are removed, the bolts formed on the first connecting part from between the joint surfaces of both connecting parts. No water leaks through the insertion hole.

  In addition, when releasing the pressing and fixing of the valve lid by the pressing means, the hydraulic pressure acting on the valve lid side can be received and supported by the lifting and lowering conveying means on the work housing side connected to the valve lid. The pressing and fixing operation of the pressing means can be easily performed with a light force.

  Furthermore, when the valve lid is taken out into the storage space in the work housing by the lifting and lowering conveying means, the bolt insertion hole of the first connecting portion is formed on the lower surface by the pressure stop means provided in the reaction force receiving portion provided in the valve box. Since the water is stopped in the pressed state from the side, it is possible to reliably prevent the water flowing out from the valve body mounting opening of the valve box from leaking through the bolt insertion hole formed in the first connecting portion.

  Therefore, it is possible to reliably remove water from the bolt insertion hole formed in the first connecting portion of the valve box while reducing the construction cost while removing the valve lid provided with the valve body and the valve stem in an indefinite state of water. It can be carried out efficiently and easily in a state where it is prevented.

  According to a second characteristic configuration of the present invention, the presser means connects the second connecting portion of the valve lid to the first connecting portion of the valve box via a presser member that is detachably attached to the valve lid. The point is that it is configured to be pressed and fixed in a watertight state.

  According to the above configuration, the second connecting portion of the valve lid is securely connected to the first connecting portion of the valve box via the pressing member attached to the valve lid without being obstructed by the constituent members existing on the upper surface of the valve lid. Can be easily pressed and fixed.

  According to a third characteristic configuration of the present invention, the pressing water stop means is provided with a water stop guide portion that engages with the bolt insertion hole of the second connection portion through the bolt insertion hole of the first connection portion. In the point.

  According to the above-described configuration, for example, at least a new valve body is provided in a state where the pressing water stop means is stretched and fixed between the reaction force receiving portion provided in the valve box and the first coupling part of the valve box. When the second valve lid is attached, when the second connection portion of the other valve lid comes into contact with the first connection portion of the valve box, the water stop guide portion of the pressing water stop means is the bolt of the first connection portion. Since it is engaged with the bolt insertion hole of the second connecting portion through the insertion hole, the fixed connecting operation between the second connecting portion of the other valve lid and the first connecting portion of the valve box by the bolt and nut is surely and easily performed. It can be carried out.

  According to a fourth characteristic configuration of the present invention, the reaction force receiving portion is provided on an outer surface of the vertical valve box portion orthogonal to an intermediate portion of the horizontal valve box portion connected to the fluid piping system in the valve box. The projecting portion is formed by a protruding projection and a split clamping ring that is clamped and fixed to the protruding portion.

  According to the above configuration, a large reaction force when the pressing water stop means is stretched and fixed between the split holding ring of the reaction force receiving portion provided in the valve box and the first connecting portion of the valve box is divided and held. The ring can be securely received and supported by the projection on the side of the sturdy valve box that is held and fixed in the engaged state.

  Therefore, a separate load support device is provided to support the split clamping ring so that it does not slip along the outer surface of the valve box, as in the case where the split clamping ring is clamped and fixed to the outer surface of the valve box. There is no need, and it is possible to promote the reduction of construction costs, and to facilitate and improve the assembly work at the construction site.

  And since the projection part is formed in the vertical valve box part of a valve box, the distance from this projection part to a 1st connection part becomes short, and the compacting of a press water stop means can be achieved.

  According to a fifth characteristic configuration of the present invention, the reaction force receiving portion is formed on an outer surface of the vertical valve box portion orthogonal to an intermediate portion of the horizontal valve box portion connected to the fluid piping system in the valve box. The split holding ring is clamped and fixed, and the leg portion is configured to receive and support the reaction force acting on the split holding ring on the lateral valve box portion.

  According to the above configuration, when the pressing water stop means is stretched and fixed between the first coupling portion of the valve box and the divided holding ring held and fixed to the outer surface of the vertical valve box part of the valve box, the divided holding ring A large reaction force acting can be reliably received and supported by the sturdy valve box side valve box part via the leg part.

  Moreover, removing the valve lid with the valve element and the valve stem in an indefinite water state, even for existing general gate valves, simply by preparing a split clamping ring and reaction force transmission legs. Therefore, the bolt insertion hole of the first connecting portion of the valve box can be reliably and easily water-stopped from the lower surface side.

  According to a sixth characteristic configuration of the present invention, the annular mounting frame is clamped and fixed in a watertight manner at a portion of the first connecting portion of the valve box that protrudes radially outward from the second connecting portion of the valve lid. There is in point.

  According to the above configuration, the annular mounting frame is easily held and fixed in the engaged state by using the protruding portion of the first connecting portion on the valve box side that protrudes radially outward from the second connecting portion on the valve lid side. Therefore, even if the load on the work housing equipped with the working on-off valve and the lifting / lowering conveying means acting on the annular mounting frame and the load on the valve lid taken out by the lifting / lowering conveying means are applied, this large load is robust. It can be reliably received and supported at the protruding portion of the first connecting portion on the side of the valve box.

  A seventh characteristic configuration according to the present invention is a gate valve used in the valve lid removal method of the gate valve according to the fourth characteristic configuration, wherein the protrusion is formed on the outer surface of the vertical valve box portion of the valve box. It is in a point that it is integrally formed in an annular shape in a posture parallel to or substantially parallel to one connecting portion.

  According to the above configuration, the split clamping ring generates a large reaction force when the pressing water stop means is stretched and fixed between the split clamping ring of the reaction force receiving portion provided in the valve box and the first coupling part of the valve box. Can be securely received and supported by a sturdy valve box-side projection that is held and fixed in an engaged state, and this projection is annular in a posture that is parallel or substantially parallel to the first connecting portion. Since they are integrally formed, it is possible to facilitate the attachment of the press water stop means and stabilize the posture, and it is possible to improve the load support function by the protrusions.

  Therefore, a load supporting device for supporting the split holding ring so that it does not fall off along the outer surface of the valve box as in the case where the split holding ring is clamped and fixed to the smooth outer surface of the valve box. There is no need to provide it separately, and it is possible to promote a reduction in construction costs, and it is possible to facilitate and improve the assembly work at the construction site.

The partially cutaway side view of the gate valve connection location of the water supply system which shows 1st Embodiment of this invention Partially cutaway side view with an annular mounting frame attached Partially cutaway side view when pressed and fixed with the presser Partial cutaway side view with work housing installed Partially cutaway side view when the valve lid is taken out into the storage space of the work housing The partially cutaway side view of the gate valve connection location of the water supply piping system showing the second embodiment of the present invention Partially cutaway side view when pressed and fixed with the presser Partial cutaway side view with work housing installed

[First Embodiment]
FIG. 1 shows a gate valve V1 that is flange-joined in the middle of a water pipe 1 of a water pipe system that is an example of a fluid pipe constituting the fluid pipe system.
The gate valve V1 includes a valve box 2 made of cast iron that is connected to the upstream and downstream water pipes 1 and has a substantially inverted T shape when viewed from the side, and a valve formed at the upper end of the valve box 2. A cast iron valve lid 4 mounted on the body mounting port 3 from above and a valve rod 5 penetrating the valve lid 4 are detachable from the valve body mounting port 3 of the valve box 2. And a valve body 6 to which a rubber lining is attached.

  The valve box 2 includes a pair of connection flanges 2A that are fixedly connected to the connection flanges 1A of the both water pipes 1 by bolts 7A and nuts 7B of the first fastening means 7, and has a circular cross-sectional shape. Portion 2B, and a vertically oriented valve box portion 2C having a substantially rectangular cross-sectional shape (cornered rectangular shape) formed integrally in a direction orthogonal to the central portion in the flow axis axis direction of the horizontally oriented valve box portion 2B. In addition, a plurality of bolt insertion holes 2a are formed at predetermined intervals in the circumferential direction on the outer peripheral surface of the valve body mounting port 3 side on the outer peripheral surface of the vertically oriented valve box portion 2C. The annular first connecting portion 2D is integrally formed so as to project outward in the radial direction.

  The valve lid 4 can be joined to the first connecting portion 2D of the valve box 2 from above and below, and a bolt insertion hole 4a is formed at a portion corresponding to the bolt insertion hole 2a of the first connecting portion 2D. A second connecting portion 4A is integrally formed, and a shaft support portion 4B is provided at the center portion of the valve lid 4 to support the valve rod 5 in a watertight manner so as to be freely rotatable.

  The first connecting portion 2D of the valve box 2 and the second connecting portion 4A of the valve lid 4 are a bolt insertion hole 2a of the first connecting portion 2D and a bolt insertion hole 4a of the second connecting portion 4A that face each other in the vertical direction. Are fixedly connected by tightening operation with the bolts 8A and nuts 8B of the second fastening means 8 inserted into the ring, and an annular seal mounting groove 4b formed on the lower surface of the second connecting portion 4A of the valve lid 4 includes a bolt A gasket 9, which is an example of a sealing material that makes a space between the joint surfaces of the first connecting portion 2 </ b> D and the second connecting portion 4 </ b> A by a tightening operation of the 8 </ b> A and the nut 8 </ b> B, is attached.

  Further, the valve body 6 screwed into the screw shaft portion of the valve stem 5 is opened at the flow path opening position (valve open position) by the rotation operation of the angular shaft-like rotation operation portion 5 a formed at the upper end portion of the valve stem 5. ) And the flow path blocking position (valve closing position).

  The first connecting portion 2D of the valve box 2 is configured to have a larger diameter than the second connecting portion 4A of the valve lid 4, and an annular protruding portion (hereinafter, referred to as “diameter outward” from the second connecting portion 4A). 2d (described as an annular projecting portion) is configured as an attachment portion for holding and fixing an annular attachment frame A, which will be described later, surrounding at least a part of the valve lid 4 including the second connecting portion 4A in a watertight state.

  Furthermore, on the outer surface of the vertically oriented valve box part 2C of the valve box 2, it is possible to support a press water stop means C (described later) that stops the bolt insertion hole 2a of the first connecting part 2D from the lower surface side in a pressed state, and The annular protrusion 2E constituting a part of the reaction force receiving portion D capable of receiving the reaction force at the time of pressing water stopping of the pressing water stopping means C is parallel or substantially parallel to the first connecting portion 2D. Are integrally formed.

  Next, among the gate valves V1 connected to the water pipe 1 on the upstream side and the downstream side of the water pipe system, when the valve body 6 having a shorter life than the valve box 2 has reached the set durable life, or A valve lid removal method for removing the valve lid 4 provided with the valve body 6 and the valve stem 5 from the valve box 2 in an indefinite water state when a malfunction of the valve body 6 occurs will be described.

[1] FIG. 2 shows that at least the second connecting portion 4A is disposed in an annular projecting portion 2d that protrudes radially outward from the second connecting portion 4A of the valve lid 4 in the first connecting portion 2D of the valve box 2. In detail, the annular mounting frame A that surrounds a part of the valve lid 4 including the upper surface of the first connecting portion 2D and the upper and lower middle equivalent positions of the valve stem 5 in a watertight state is enclosed. The process of attaching is shown.

  The annular mounting frame A is formed in a cylindrical case shape applied from the lower side mounting frame member 15 of the divided structure applied from the lower side of the annular projecting portion 2d of the first connecting portion 2D and the upper side of the annular projecting portion 2d. The upper mounting frame member 16 and third fastening means 17 for clamping the two mounting frame members 15 and 16 while pulling them together and holding and fixing them to the annular projecting portion 2d are constituted.

  The third fastening means 17 includes screw holes (not shown) formed at a plurality of locations in the circumferential direction on the lower surface of the upper mounting frame member 16 and bolt insertion holes (not shown) formed in the lower mounting frame member 15. And a bolt 17A screwed into the screw hole of the upper mounting frame member 16 from below.

  An annular restricting projection 15A for position restriction protruding upward is integrally formed on the radially outer side portion of the upper surface of the lower mounting frame member 15 of the divided structure, and on the lower surface of the upper mounting frame member 16 The lower mounting frame member 15 is engaged between the annular restricting projection 15A and the outer peripheral surface of the first connecting portion 2D, and the lower mounting frame member 15 and the upper mounting frame member 16 are relatively moved in the horizontal direction. An annular engagement protrusion 16A is formed so as to integrally protrude.

  Further, in the annular seal mounting groove 16a formed in the portion of the lower surface of the upper mounting frame 16 in contact with the annular projecting portion 2d of the first connecting portion 2D, the first fastening operation 17 is tightened with the bolt 17A. A gasket 18, which is an example of a sealing material that makes a space between the opposing surfaces of the connecting portion 2 </ b> D and the upper mounting frame member 16 watertight, is attached.

[2] FIG. 3 shows the second connecting portion 4A of the valve lid 4 via a presser member 20 which is detachably attached to the valve lid 4 by the presser means B provided on the upper mounting frame member 16 of the annular mounting frame A. A step of pressing and fixing the first connection portion 2D of the valve box 2 in a watertight state, and a second fastening in which the first connection portion 2D and the second connection portion 4A are fixedly connected at the time of pressing and fixing by the pressing means B. By the step of removing the bolts 8A and nuts 8B of the means 8 and the pressing water stopping means C mounted between the first connecting part 2D of the valve box 2 and the reaction force receiving part D provided in the valve box 2, The process of water-stopping each bolt insertion hole 2a of 1st connection part 2D from the lower surface side in a press state is shown.

  The presser member 20 is a lower end of the presser cover portion 20A in a state of being in contact with the upper surface of the presser cover portion 20A that is externally attached to the shaft support portion 4B of the valve lid 4 and the second connecting portion 4A of the valve lid 4. And a valve lid 4 having a valve cylinder 6 and a valve rod 5 having an inner diameter that allows the rotation operation portion 5a of the valve rod 5 to protrude. It is comprised from the to-be-connected part 20C detachably screwed and connected to the female screw of the connecting part 36 on the up-and-down conveying means E side that moves up and down.

  At a plurality of locations in the circumferential direction of the peripheral wall portion 20b of the presser cover portion 20A of the presser member 20, the presser member 20 resists the load of the valve lid 4 provided with the valve body 6 and the valve stem 5 suspended by the lifting and lowering conveying means E. A set screw 19 which is an example of a tightening fixing means for tightening and fixing the presser cover portion 20A and the shaft support portion 4B of the valve lid 4 is provided.

  The holding means B includes screw cylinders 21 communicating with the internal space of the upper mounting frame 16 at a plurality of circumferential positions (four in the present embodiment) in the upper and lower intermediate portions of the upper mounting frame 16. Are fixed to each screw cylinder 21 at the outer peripheral edge of the upper surface side of the flange portion 20B of the presser member 20. It is configured by screwing a push-in bolt 22 provided with a taper-shaped pressing surface 22a that comes into contact with the tapered surface 20a in the horizontal direction.

  When the plurality of pressing bolts 22 of the pressing means B are screwed, the pressing member 20 is brought into contact with the tapered pressing surface 22a of each pressing bolt 22 and the tapered surface 20a of the flange portion 20B of the pressing member 20. Is pressed strongly against the second connecting portion 4A side of the valve lid 4, and the second connecting portion 4A of the valve lid 4 strongly presses the first connecting portion 2D of the valve box 2, so that the holding means B In the state of being strongly pressed and fixed with the second fastening means 8, even if the pressing force by the bolts 8A and nuts 8B of the second fastening means 8 is released, the gap between the second connecting portion 4A of the valve lid 4 and the first connecting portion 2D of the valve box 2 It is possible to reliably maintain the gasket 9 interposed therebetween in a compressed watertight state.

  Therefore, after the pressing and fixing by the holding means B is finished, the bolt 8A and the nut 8B of the second fastening means 8 are removed, and the first connecting portion 2D of the valve box 2 and the second connecting portion 4A of the valve lid 4 are fixed. Unlink.

  Further, the annular protrusion 2E formed on the longitudinal valve box 2C of the valve box 2 has a plurality of engagement recesses 23c that engage with the upper surface and the outer peripheral surface of the protrusion 2E in the circumferential direction. The split clamping ring 23 divided into two is clamped and fixed. The split clamping ring 23 and the projection 2E on the valve box 2 side support and place the pressing water-stopping means C, and the pressing water-stopping means. A reaction force receiving portion D that can reliably receive the reaction force at the time of C pressing water stop is configured.

  As shown in FIG. 4, the split clamping ring 23 is composed of split clamping ring bodies 23A and 23B that are divided into two in the circumferential direction, and connecting pieces formed at both ends of both split clamping ring bodies 23A and 23B. Both split holding ring bodies 23A, 23B that are sheathed from the outside in the radial direction with respect to the projecting portion 2E by tightening the opposing parts of 23a, 23b with bolts 24A, nuts 24B of the fourth fastening means 24. It is configured to be clamped and fixed in an engaged state while reducing the diameter.

  The pressing water stop means C attached after the removal of the second fastening means 8 is a valve box among the water stopping press ring bodies 27 having the same two-divided structure or opening / closing structure as the both split holding ring bodies 23A, 23B of the divided holding ring 23. The water stop operation bolt 26 that can be engaged with each bolt insertion hole 2a is screwed into a portion corresponding to the bolt insertion hole 2a of the second first connecting portion 2D, and the head portion 26a of each water stop operation bolt 26 is attached. By rotating each water stop operating bolt 26 to the pressing side in a state where it is placed on the upper surfaces of both split holding ring bodies 23A and 23B, the upper surface of the water stop pressing ring body 27 is brought into the lower surface of the first connecting portion 2D. It is configured to be pressed.

  On the upper surface of the water stop pressing ring body 27, a packing 28 for watertightly closing the lower opening of each bolt insertion hole 2a on the lower surface of the first connecting portion 2D is provided, and the upper end of each water stop operation bolt 26 is provided. The water stop guide part 26b which engages and guides to the bolt insertion hole 4a of the 2nd connection part 4A through the bolt insertion hole 2a of 1st connection part 2D is comprised, and a part is comprised in a conical taper shape.

  The pressing water stop means C is mounted between the first connecting portion 2 </ b> D and the split clamping ring 23 in which a plurality of water stopping operation bolts 26 are screwed in advance to the water stopping press ring body 27. .

  And after the removal of the 2nd fastening means 8, the water stop guide part 26b of each water stop operation bolt 26 of the press water stop means C is inserted in the bolt insertion hole 2a of 1st connection part 2D, A split holding ring 23 is attached to the projecting portion 2E, and the water stop operation bolts 26 are rotated to the pressing side while the heads 26a of the water stop operation bolts 26 are placed on the upper surfaces of the split holding rings 23. The packing 28 provided on the upper surface of the water pressing ring body 27 is pressed against the lower surface of the first connecting portion 2D, and the lower openings of the bolt insertion holes 2a on the lower surface of the first connecting portion 2D are closed in a watertight manner.

[3] FIG. 4 shows a housing attachment process in which a work housing H provided with a lifting and lowering conveying means E connected to the work opening / closing valve V2 and the valve lid 4 is attached to the upper attachment frame member 16 of the annular attachment frame A in a watertight state. Indicates.

  Of the valve case 30 of the work on-off valve V2, the inner surface of the fitting mounting cylinder portion 30A that is mounted on the upper mounting frame member 16 of the annular mounting frame A from above is mounted on the inner surface of the upper mounting frame member 16. The annular protrusion 30a for fitting position regulation which contacts the end surface from above is integrally formed, and the upper end of the outer peripheral surface of the upper mounting frame member 16 is provided at a plurality of positions in the circumferential direction of the fitting mounting cylinder portion 30A of the valve case 30. A pulling bolt 31 having a tapered pressing surface 31a that abuts from the horizontal direction on the lower tapered surface 16c of the annular protrusion 16b formed to protrude from the portion is screwed.

  In addition, the face of the valve case 30 facing the inner corner of the fitting mounting cylinder 30A and the fitting position regulating annular projection 30a and the upper tapered surface 16d of the annular projection 16b of the upper mounting frame 16 An O-ring (not shown), which is an example of a sealing material, is mounted between the annular protrusions for restricting the fitting position of the valve case 30 while the O-ring is compressed into a watertight state by tightening the pulling bolt 31. 30a is pulled and fixed to the upper end surface of the upper mounting frame member 16 of the annular mounting frame A.

  The work housing H is provided with a work housing body 33 having a lower connection flange 33A that is fixedly connected to the upper connection flange 30B of the valve case 30 by a bolt 32A and a nut 32B of the fifth fastening means 32 in a watertight state. A storage space S in which the valve lid 4 including the valve body 6 and the valve stem 5 can be accommodated is formed in the work housing body 33.

  The lifting and lowering conveying means E is threadably engaged with the lower end portion of the lifting shaft 35 slidably supported through the central portion of the top plate portion of the work housing body 33 so as to be detachable from the connected portion 20C of the pressing member 20. A connecting portion 36 to be connected is provided.

  In this housing mounting step, the valve lid 4 is pressed and fixed to the valve box 2 side by the tightening operation of the plurality of pressing bolts 22 of the pressing means B.

[4] FIG. 5 shows that the pressing and fixing of the valve lid 4 by the holding means B is released, and after the valve lid 4 is taken out into the storage space S of the work housing H by the lifting and lowering conveying means E, the work on-off valve V2 is shown. The process of valve-closing operation is shown.

  Specifically, the plurality of pressing bolts 22 of the pressing means B are loosened, and the tapered pressing surface 22a of each pressing bolt 22 is a taper formed on the outer peripheral side of the upper surface side of the flange portion 20B of the pressing member 20. Detach from the surface 20a radially outward.

  Thereafter, the valve lid 4 mounted on the valve box 2 is moved up to a predetermined storage position in the storage space S of the work housing main body 33 by a crane or the like connected to the lift shaft 35, and then the work on-off valve V2 is used. The valve body 39 is closed, and the valve lid 4 taken out in the storage space S of the work housing H is removed.

  In the removal process of the valve lid 4, the bolt 32 </ b> A and the nut 32 </ b> B of the fifth fastening means 32 that fixedly connects the upper connection flange 30 </ b> B of the valve case 30 and the lower connection flange 33 </ b> A of the work housing body 33 are removed, The work housing body 33 having the removed valve lid 4 and the lifting and lowering conveying means E is suspended and conveyed to a predetermined position by a crane or the like and removed.

[5] When another valve lid 4 equipped with at least a new valve body 6 is to be attached after the removal process of the valve lid 4, a procedure substantially reverse to the above-described removal work process is performed.
That is, after the removal process of the valve lid 4,
Connecting the connected portion 20C of another valve lid 4 equipped with at least a new valve body 6 to the connecting portion 36 of the lifting shaft 35 of the lifting and lowering conveying means E provided in the work housing H;
A step of fixing and connecting the lower connection flange 33A of the work housing main body 33 of the work housing H and the upper connection flange 30B of the valve case 30 of the work on / off valve V2 in a watertight state with the bolts 32A and nuts 32B of the fifth fastening means 32. When,
The valve body 29 of the work opening / closing valve V2 is opened, and another valve lid 4 in the storage space S of the work housing H is lowered to the valve box 2 side by the lift shaft 35 of the lift conveying means E, A step of joining and mounting the second connecting portion 4A of another valve lid 4 to the first connecting portion 2D of the valve box 2;
A step of pressing and fixing another valve lid 4 to the valve box 2 side with a plurality of pressing bolts 22 of the holding means B;
After rotating the lifting shaft 35 to the screw release side to release the connection between the connecting portion 36 of the lifting shaft 35 and the connected portion 20C of another valve lid 4, the upper mounting frame member 16 of the annular mounting frame A is released. And the pulling bolt 31 that is fixedly connected to the valve case 30 of the work opening / closing valve V2 is operated to release the lock, and the work opening / closing valve V2 and the lifting / lowering conveying means E are provided from the upper mounting frame 16 of the annular mounting frame A Removing the work housing H;
Removing the pressure stop means C assembled between the first connecting portion 2D of the valve box 2 and the split holding ring 23;
A step of fixing and connecting the second connecting portion 4A of another joined valve lid 4 and the first connecting portion 2D of the valve box 2 in a watertight state with the bolts 8A and nuts 8B of the second fastening means 8,
Third fastening means for releasing the pressing of the other valve lid 4 by the plurality of pushing bolts 22 of the holding means B and fixedly connecting the upper mounting frame member 16 and the lower mounting frame member 15 of the annular mounting frame A to each other. A step of unlocking 17 and removing the upper mounting frame member 16 from the lower mounting frame member 15;
Removing the lower mounting frame member 15 and the split holding ring 23 from the valve box 2;
Execute.

  In the first embodiment described above, another valve lid 4 equipped with at least a new valve body 6 is attached after the removal process of the valve lid 4, but instead of this another valve lid 4, a valve box A lid for closing the valve body mounting port 3 of 2 in a watertight state may be attached, and further, a assembly of a repair valve and a valve attachment member for attaching the repair valve to the first connecting portion 2D of the valve box 2 may be attached. Also good.

[Second Embodiment]
FIGS. 6-8 shows the valve cover removal construction method of the gate valve V1 by which 1st connection part 2D of the valve box 2 and 2nd connection part 4A of the valve cover 4 are comprised by the same diameter.

  [6] FIG. 6 shows a step of attaching an annular mounting frame A surrounding a part of the valve lid 4 including at least the second connecting portion 4A to the first connecting portion 2D of the valve box 2 in a watertight state, and this annular mounting. The step of pressing and fixing the second connecting portion 4A of the valve lid 4 to the first connecting portion 2D of the valve box 2 in a watertight state by the pressing means B provided on the frame A is shown.

  The annular mounting frame A is a lower mounting frame member that is clamped and fixed to the outer peripheral surface of the first connecting portion 2D of the valve box 2 in a watertight state via an elastic seal member 40 (in this embodiment, a two-split structure). 41 and an upper mounting frame member 43 provided with a connecting flange 43A fixedly connected to the connecting flange 41A of the lower mounting frame member 41 in a watertight state by bolts 42A and nuts 42B of the sixth fastening means 42. Yes.

  A pair of upper and lower partition projections 41C and 41D constituting a seal mounting groove of the elastic seal material 40 are formed on the inner peripheral surface of the divided annular frame 41B of the lower attachment frame member 41, and among them, the lower partition projection 41D. Is configured as a protruding margin that comes into contact with the lower surface of the first connecting portion 2D of the valve box 2 from below.

  The upper mounting frame member 43 is configured by fixing a connecting flange 43A to the lower end of a cylindrical case body 43B that surrounds the entire valve lid 4 including the valve stem 5.

  The holding means B includes screw cylinders 21 communicating with the internal space of the upper mounting frame member 43 at a plurality of circumferential locations (four in the present embodiment) in the upper and lower intermediate portions of the cylindrical case body 43B of the upper mounting frame member 43. The screw shaft core is fixed in a state where the screw shaft core is positioned on the upper surface of the flange portion 20B of the presser member 20 or a horizontal axis core passing through the upper surface thereof, and each screw cylinder 21 is attached to the upper surface side of the flange portion 20B of the presser member 20 This is constituted by screwing a push-in bolt 22 having a taper-like pressing surface 22a that comes into contact with the taper surface 20a formed at the outer peripheral edge of the outer peripheral edge portion in the horizontal direction.

  When the plurality of pressing bolts 22 of the pressing means B are screwed, the pressing member 20 is brought into contact with the tapered pressing surface 22a of each pressing bolt 22 and the tapered surface 20a of the flange portion 20B of the pressing member 20. Is strongly pressed against the shaft support portion 4B side of the valve lid 4, and the second connecting portion 4A of the valve lid 4 strongly presses the first connecting portion 2D of the valve box 2. In the state of being strongly pressed and fixed, the second connecting portion 4A of the valve lid 4 and the first connecting portion 2D of the valve box 2 are not affected even if the tightening fixing force by the bolts 8A and nuts 8B of the second fastening means 8 is released. The gasket 9 interposed therebetween can be reliably maintained in a compressed watertight state.

  [7] FIG. 7 shows a state in which the bolt 8A and nut 8B of the second fastening means 8 that fixedly connects the first connecting portion 2D of the valve box 2 and the second connecting portion 4A of the valve lid 4 are removed, The process of water-stopping the bolt insertion hole 2a of the first connecting portion 2D from the lower surface side by the pressing water-stopping means C provided in the reaction force receiving portion D provided in the box 2 is shown.

  The reaction force receiving portion D acts on the split gripping ring 23 having a split structure (two split structure in the present embodiment) that is gripped and fixed to the outer surface of the vertically oriented valve box portion 2C of the valve box 2, and the split gripping ring 23. With the pair of left and right half force transmitting legs 45 for receiving and supporting the reaction force of the pressure-stopping means C on the lateral valve box portion 2B of the sturdy valve box 2, the pressure-stopping means C is stopped. The reaction force receiving portion D that can reliably receive the reaction force is configured.

  The split clamping ring 23 is composed of split clamping ring bodies 23A and 23B that are divided into two in the circumferential direction, and the connecting pieces 23a and 23b formed at both ends of both split clamping ring bodies 23A and 23B are opposed to each other. Both split clamping ring bodies 23 </ b> A that are sheathed from the outer side in the radial direction with respect to the outer surface of the vertically oriented valve box portion 2 </ b> C of the valve box 2 by tightening the objects with the bolts 24 </ b> A and nuts 24 </ b> B of the fourth fastening means 24. , 23B is held and fixed while being reduced in diameter.

  The pair of left and right leg portions 45 are attached to both split gripping ring bodies 23A and 23B of the split gripping ring 23, and the lower end of each leg portion 45 is a leg portion on the outer surface of the laterally facing valve box portion 2B of the valve box 2. It is formed in the circular arc-shaped recessed part along the cross-sectional shape of the contact | abutting equivalent location.

  The pressing water-stopping means C is a bolt insertion of the first connecting portion 2D of the valve box 2 in the water-stopping pressing ring body 27 having the same two-divided structure or opening / closing structure as the both split holding ring bodies 23A, 23B of the split holding ring 23. A water stop operation bolt 26 that can be engaged with each bolt insertion hole 2a is screwed into a portion corresponding to the hole 2a, and the head portion 26a of each water stop operation bolt 26 is connected to the upper surfaces of both split holding ring bodies 23A and 23B. When the water stop operation bolts 26 are rotationally operated to the pressing side in a state where they are placed on the upper surface, the upper surface of the water stop press ring body 27 is configured to be in pressure contact with the lower surface of the first connecting portion 2D.

  On the upper surface of the water stop pressing ring body 27, a packing 28 for watertightly closing the lower opening of each bolt insertion hole 2a on the lower surface of the first connecting portion 2D is provided, and the upper end of each water stop operation bolt 26 is provided. The water stop guide part 26b which engages and guides into the bolt insertion hole 2a of the said 1st connection part 2D with the proximity | contact movement to the 1st connection part 2D is comprised by comprising a part in a conical taper shape. .

  [8] FIG. 8 shows a housing attachment process in which the work housing H provided with the lifting and lowering conveying means E connected to the work opening / closing valve V2 and the valve lid 4 is attached to the upper attachment frame member 43 of the annular attachment frame A in a watertight state. Indicates.

  Of the valve case 30 of the working on-off valve V2, the inner surface of the fitting mounting cylinder portion 30A that is mounted on the cylindrical case body 43B of the upper mounting frame member 43 from above is fitted on the inner surface of the upper mounting frame member 16. An annular protrusion 30a for fitting position regulation that comes into contact with the upper end surface of the cylindrical case body 43B from above is integrally formed, and a cylindrical case is provided at a plurality of locations in the circumferential direction of the fitting mounting cylinder portion 30A of the valve case 30. A pulling bolt 31 having a tapered pressing surface 31a that abuts in a horizontal direction against a lower tapered surface 43b of an annular protrusion 43a that is formed to protrude from the upper end portion of the outer peripheral surface of the body 43B is screwed.

  In addition, the face of the valve case 30 facing the inner corner of the fitting mounting cylinder 30A and the fitting position regulating annular projection 30a and the upper tapered surface 43c of the annular projection 43a of the upper mounting frame 43. An O-ring (not shown), which is an example of a sealing material, is mounted between the annular protrusions for restricting the fitting position of the valve case 30 while the O-ring is compressed into a watertight state by tightening the pulling bolt 31. 30a is pulled and fixed to the upper end surface of the upper mounting frame member 43 of the annular mounting frame A.

  Since the other configuration and the procedure of the method are the same or substantially the same as the procedure of the configuration and the method described in the first embodiment, the same reference numerals as in the first embodiment are assigned to the same components. Additional description is omitted here.

[Other Embodiments]
(1) In each of the above-described embodiments, the first connecting portion 2D of the valve box 2 and the second connecting portion 4A of the valve lid 4 are each configured in an annular shape. However, the first connecting portion 2D and the second connecting portion 4A You may form intermittently in the circumferential direction.

  (2) In the first embodiment described above, the annular mounting frame A that surrounds at least a part of the valve lid 4 including the second connecting portion 4A is attached to the lower mounting frame member 15 of the split structure and the upper mounting of the cylindrical case shape. Although the frame member 16 is configured to be fixedly connected, the lower mounting frame member 15 and the cylindrical case-shaped upper mounting frame member 16 may be integrally formed.

  (3) As the holding means B provided on the annular mounting frame A, the second connecting portion 4A of the valve lid 4 can be pressed and fixed to the first connecting portion 2D of the valve box 2 in a watertight state. Any structure may be used.

  (4) As the reaction force receiving portion D provided in the valve box 2, any structure can be used as long as it can reliably receive the reaction force when the pressing water stopping means C is stopped. Good.

  (5) As the pressing water-stopping means C, any structure may be used as long as the bolt insertion hole 2a of the first connecting portion 2D can be stopped from the lower surface side in a pressing state.

  (6) Each of the form of the first joint 2D of the valve box 2 and the second joint 4A of the valve lid 4, the form of the housing H, the form of the lifting and lowering conveying means E, and the form of the work on-off valve V2 are under various conditions. It can be changed as appropriate.

  As described above, the removal of the valve lid provided with the valve body and the valve stem in the unreserved water state is performed from the bolt insertion hole formed in the first connection portion of the valve box while reducing the construction cost. It is possible to provide a gate valve removal method for a gate valve that can be efficiently and easily performed in a state where water leakage is reliably prevented, and a gate valve that contributes to the efficiency and ease of the removal work.

A Annular mounting frame B Presser means C Press water stop means D Reaction force receiving part E Lifting and conveying means H Work housing S Storage space V1 Gate valve V2 Work on / off valve 2 Valve box 2D First connection part 2E Projection part 2a Bolt insertion hole 2d protruding part (annular protruding part)
3 Valve body mounting port 4 Valve lid 4A Second connecting part 8A Bolt 8B Nut 20 Presser member 23 Divided clamping ring 26b Water stop guide part 45 Leg part

Claims (7)

A valve box connected to the fluid piping system, a valve lid provided with a second connecting part fixedly connected by bolts and nuts to a first connecting part provided in a valve body mounting port of the valve box, and the valve Of the gate valve provided with a valve body that is detachably mounted from the valve body mounting port of the valve box through a valve rod penetrating through the lid, the valve lid provided with the valve body and the valve rod is not interrupted. A valve cover removal method for a gate valve that is removed from a valve box in a water state,
Attaching an annular mounting frame that surrounds at least a part of the valve lid including the second connecting portion to the first connecting portion of the valve box in a watertight state;
A step of pressing and fixing the second connecting portion of the valve lid against the first connecting portion of the valve box in a watertight state by a pressing means provided on the annular mounting frame;
Removing the bolts and nuts fixedly connecting the first and second connecting parts;
A step of water-stopping the bolt insertion hole of the first connecting portion in a pressed state from the lower surface side by means of a pressure-stopping device provided in the reaction force receiving portion provided in the valve box;
A step of attaching to the annular mounting frame a work housing provided with a work on-off valve and a lift conveying means coupled to the valve lid;
Releasing the pressing and fixing of the presser means, and taking out the valve lid into the storage space in the work housing by the lifting and lowering transport means, and then closing the work on-off valve; and
Removing the valve lid taken out in the storage space in the working housing;
The valve lid removal method of the gate valve equipped with.   The presser means is configured to press and fix the second connecting portion of the valve lid against the first connecting portion of the valve box in a watertight state via a presser member detachably attached to the valve lid. The valve lid removal construction method of the gate valve according to claim 1.   3. The gate valve according to claim 1, wherein the pressing water stop means is provided with a water stop guide portion that engages with the bolt insertion hole of the second connection portion through the bolt insertion hole of the first connection portion. Valve lid removal method.   The reaction force receiving portion protrudes on the outer surface of the vertical valve box portion orthogonal to the intermediate portion of the horizontal valve box portion connected to the fluid piping system of the valve box, and the protrusion The valve lid removal method of the gate valve of any one of Claims 1-3 comprised from the division | segmentation clamping ring clamped and fixed to a part.   The reaction force receiving portion is a split clamping ring that is clamped and fixed to the outer surface of the vertical valve box portion perpendicular to the intermediate portion of the horizontal valve box portion connected to the fluid piping system of the valve box, and The valve lid removal method of the gate valve of any one of Claims 1-3 comprised from the leg part which accepts and supports the reaction force which acts on a division | segmentation holding ring in a sideways valve box part.   The annular mounting frame is clamped and fixed in a watertight manner to a portion of the first connecting portion of the valve box that protrudes radially outward from the second connecting portion of the valve lid. The valve lid removal method for the gate valve according to item 1.   5. A gate valve used in the valve lid removal method of the gate valve according to claim 4, wherein the projecting portion is parallel or substantially parallel to the first connection portion on an outer surface of the vertical valve box portion of the valve box. A gate valve that is integrally formed in an annular shape in a posture.

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