How to install and remove the work valve

Abstract

To provide an attachment method and a removal method of a work valve which enables reduction of a difficulty in attachment of the work valve to a housing.SOLUTION: An attachment method of a work valve 4 is used to perform predetermined work in a state where flow of a fluid is not interrupted inside a housing 2 attached to a fluid pipe 1 in a sealed manner. The work valve 4 includes: a valve box 41 attached to an opening 2a of the housing 2; a valve lid 43 attached to the valve box 41; a valve rod 43a which is provided at the valve lid 43 and in which an operation end 43b at a tip protrudes to the outside of the valve lid 43; and a valve body 42 which is detachably attached to the valve rod 43a and provided so as to move forward or rearward in the valve box 41 and the valve lid 43 by rotation of the valve rod 43a. The attachment method includes: a first step in which the valve rod provided at the valve lid 43 is attached to the valve body 42 in the valve box 41 installed at the opening 2a of the housing 2; and a second step in which the valve lid 43 is attached to the valve box 41.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for installing an operating valve for performing a predetermined operation within a housing that seals a fluid pipe in an uninterrupted flow state. [Background technology]

[0002] In order to deal with deterioration over time or to form a new branch path, a part of the existing fluid pipe that constitutes an existing pipeline through which water, gas, etc. flows may be replaced with a new fluid pipe or a deteriorated pipeline may be blocked. In such cases, an existing opening that has been installed in advance may be opened or a new opening may be formed by cutting or the like.

[0003] In the operation including the step of opening an opening like this, a method of performing the operation under an uninterrupted flow condition using an operating valve is known. The operating valve is mainly composed of a valve body attached to the opening of a housing which is fixed in a sealed manner to the fluid pipe, a valve cover attached to the valve body, and a valve element which can move back and forth within the valve body and the valve cover. When the opening of the fluid pipe is open, the valve element can be moved to a closing position which closes the inside of the valve body to prevent fluid leakage to the outside of the housing, and can be moved to an open position which retracts into the valve cover to allow access to the opening.

[0004] The operation valve is generally transported to the installation location using a crane and attached to the housing. In particular, when the diameter of the fluid pipe is large, the structure of the operation valve also becomes large and heavy. Therefore, in order to transport the operation valve in an assembled state, a large crane with high lifting capacity must be prepared, and a large space is required for placing and maneuvering the crane.

[0005] Therefore, for example, there is a method of attaching a working valve to a housing by dividing the working valve into a valve body and a valve cover with a valve disc inserted, attaching the valve body to the opening of the housing, and then attaching the valve cover with the valve disc inserted to the valve body, as shown in the method of attaching a working valve to a housing, as shown in Patent Document 1. This method makes it possible to reduce the lifting capacity required for one transportation. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2018-159397 A (page 8, Figure 14) Summary of the Invention [Problem to be solved by the invention]

[0007] The method for installing a service valve described in Patent Document 1 allows the separate service valves to be assembled and attached to the housing using a crane with low lifting capacity, making it possible to install the service valve even in work environments where large space is limited. However, the valve cover with the inserted valve disc must be moved horizontally while aligning its height with the previously installed valve box, and the tip of the valve disc, which protrudes slightly outward from the valve cover, must be inserted into the valve box. This makes it difficult to visually confirm the tip of the valve disc. Furthermore, since the valve disc itself is not suspended by a crane but the valve cover with the inserted valve disc is suspended directly, the valve disc inside the valve cover is unstable and may swing during installation, making it difficult to accurately insert and install the tip of the valve disc into the valve box. Furthermore, if the tip of the valve disc comes into contact with an opening in the valve box, the valve disc may be damaged, potentially affecting the sealing performance of the service valve itself.

[0008] The present invention has been made in view of these problems, and has as its object to provide a method for mounting an operating valve that reduces the difficulty of mounting the operating valve to a housing. [Means for solving the problem]

[0009] In order to solve the above problem, the method for installing a working valve of the present invention comprises: A method for installing a working valve for performing a predetermined operation in an enclosure that is hermetically attached to a fluid pipe in an uninterrupted flow state, comprising: The working valve includes a valve body attached to the opening of the housing, a valve cover attached to the valve body, and a valve body provided so as to be movable back and forth within the valve body and the valve cover, a first step of installing the valve body in the opening of the housing; a second step of inserting the valve body into the valve body; a third step of connecting the valve body to an operating portion for moving the valve body back and forth; and a fourth step of attaching the valve cover to the valve body. According to this feature, the valve body, valve disc, and valve cover of the operating valve are each separated, and the valve is first inserted into the valve body installed in the housing, and then the valve cover is attached to the valve body. Since the valve disc is inserted into the valve body separately from the valve cover, the entire valve disc can be grasped and its position can be controlled, allowing the valve disc to be inserted into the opening of the valve body with precision. In addition, the risk of the valve disc coming into contact with the opening of the valve body is reduced, so the valve disc is not damaged and the sealing of the operating valve itself can be maintained. Furthermore, since the operating valve is separated into the valve body, valve disc, and valve cover and is lifted and transported separately by a crane, the weight of each component to be lifted by the crane is small, allowing the use of a small crane, so work can be carried out even in situations where there is not enough work space. In addition, the small weight of each component improves handling and makes it easier to attach the operating valve to the housing.

[0010] In the third step, the retraction of the valve element inserted into the valve body is restricted by a restricting means. According to this feature, the valve element inserted into the valve box can be prevented by the restricting means from retracting and falling when connected to the operating portion for moving the valve element back and forth.

[0011] In the second step, the valve body is suspended by a plurality of suspension supports in the direction of travel, and after the front side of the valve body is inserted into the valve box, the suspension supports are released sequentially from the front side in the direction of travel. According to this feature, even if the suspension support part on the front side of the valve body in the direction of travel is released, the load on the front side of the valve body is supported near the opening of the valve box, so the valve body can be inserted further into the valve box while maintaining an approximately parallel state similar to when it is suspended by a crane.

[0012] In the fourth step, the entire valve body is inserted into the opening of the valve body. According to this feature, since the valve body is not exposed, it is easy to align the valve cover when attaching it to the valve box, and it is possible to prevent the rear end of the valve body from coming into contact with the valve cover, thereby avoiding damage to the rear end of the valve body.

[0013] In the fourth step, the valve cover is moved closer to the valve body by operating the operating portion connected to the valve body. According to this feature, by operating the operating part connected to the valve body inserted into the valve box, the valve cover can be brought closer to the valve box, and by working in conjunction with the lifting support provided by the crane, it is possible to easily connect the valve cover and the valve box.

[0014] In the second step, the front side of the valve body in the traveling direction is placed on a placement portion that protrudes into the opening of the valve box, and then the valve body is inserted into the valve box. According to this feature, when inserting the valve body into the valve box, it can be placed on a mounting portion that protrudes into the opening of the valve box and aligned, allowing the valve body to be inserted smoothly without colliding with the valve box.

[0015] the operating unit includes a valve stem that is provided on the valve cover and moves the valve element back and forth; In the third step, the tip of the valve stem is attached to the rear end of the valve disc inserted into the valve body. According to this feature, by attaching the rear end of the valve body to the tip of the valve rod, it is possible to connect the valve body to the operating part for moving the valve body back and forth.

[0016] The valve body has a locking portion at an end portion on the rearward direction side that is connected in the vertical direction, The valve stem is characterized in that the locking portion is locked to the locked portion. According to this feature, the valve stem can be attached to the valve body by moving the locked portion of the valve stem in the vertical direction and locking it with the locking portion of the valve body, making attachment easy. [Brief explanation of the drawings]

[0017] [Figure 1] 1A and 1B are a side cross-sectional view and a plan view showing a step (first step of the mounting step) of mounting a valve body of an operating valve to a housing in the embodiment. [Figure 2] FIG. 4 is a side cross-sectional view showing how the valve body is attached to the valve box (a second step of the attachment step). [Figure 3] FIG. 4 is a side cross-sectional view showing how the valve body is attached to the valve box (a second step of the attachment step). [Figure 4] 4A and 4B are a side cross-sectional view and a plan view showing how the valve body is attached to the valve box (a second step of the attachment step). [Figure 5] FIG. 10 is a side cross-sectional view showing how a valve stem provided on a valve cover is connected to a valve disc inserted into a valve body (third step of the attachment step). [Figure 6] FIG. 10 is a side cross-sectional view showing a modified example of connecting a valve stem provided on a valve cover to a valve disc inserted into a valve body (third step of the attachment step). [Figure 7] FIG. 10 is a plan view showing a modified example of connecting a valve stem provided on a valve cover to a valve disc inserted into a valve body (third step of the attachment step). [Figure 8] FIG. 10 is a cross-sectional side view showing how the valve cover is attached to the valve box (fourth step of the attaching process). [Figure 9] FIG. 10 is a cross-sectional side view showing how the valve cover is attached to the valve box (fourth step of the attaching process). [Figure 10]FIG. 10 is a side cross-sectional view showing how a mounting flange cylinder is attached to a work valve in the process of installing the cutting machine. [Figure 11] FIG. 10 is a side cross-sectional view showing how a cutter and a cover are attached to a mounting flange tube in the process of installing the cutting machine. [Figure 12] FIG. 10 is a side cross-sectional view showing the state in which the lid body is fixed to the mounting flange cylinder in the process of installing the cutting machine. [Figure 13] FIG. 2 is an explanatory diagram showing the structure of a drive mechanism. [Figure 14] FIG. 10 is a side cross-sectional view showing a state in which a shaft member and a cutter are connected in a step of installing the cutting machine. [Figure 15] FIG. 10 is a side cross-sectional view showing the removal of a jack and a fixing jig in the process of installing the cutting machine. [Figure 16] 10 is a side cross-sectional view showing a state in which the case portion of the drive mechanism and the cover body are connected in the process of installing the cutting machine. FIG. [Figure 17] FIG. 10 is a side cross-sectional view showing how a fluid pipe is cut by a cutting machine. [Figure 18] FIG. 10 is a side cross-sectional view showing the state in which the section of the fluid pipe has been collected. [Figure 19] FIG. 10 is a side cross-sectional view showing a state in which a cylindrical member is attached to an operating valve in the process of installing a valve introducer. [Figure 20] 10 is a side cross-sectional view showing a state in which a partition wall, an opening / closing shaft, and a valve body of a butterfly valve are attached to a cylindrical member in a process of installing a valve introducer. FIG. [Figure 21] FIG. 10 is a side cross-sectional view showing the butterfly valve constructed by attaching the upper cover in the process of installing the valve introducer. [Figure 22] FIG. 10 is an explanatory view showing a state in which a mounting flange cylinder is attached to a cylindrical member in a process of installing a valve introducer. [Figure 23] FIG. 10 is a side cross-sectional view showing the installation of a valve hanger and a cover in the process of installing a valve introducer. [Figure 24] FIG. 10 is a side cross-sectional view showing the state in which the lid body is fixed to the mounting flange cylinder in the process of installing the valve introducer. [Figure 25]FIG. 10 is a side cross-sectional view showing the state in which the shaft member and the valve hanger are connected in the process of installing the valve introducer. [Figure 26] FIG. 10 is a side cross-sectional view showing a state in which a jack and a fixing jig are removed in the process of installing the valve introducer. [Figure 27] FIG. 10 is a side cross-sectional view showing the butterfly valve and the valve hanger connected in the process of installing the valve introducer. [Figure 28] 10 is a side cross-sectional view showing a state in which a butterfly valve is installed at a cut portion of a fluid pipe by a valve introducer. FIG. [Figure 29] A side cross-sectional view showing the valve suspension fitting being pulled up into the cylindrical member and the mounting flange tube. [Figure 30] FIG. 10 is a side cross-sectional view showing a modified example of the cutting machine. [Figure 31] FIG. 2 is a side cross-sectional view showing a state in which the valve introducer is removed from the housing. [Figure 32] FIG. 2 is a side cross-sectional view showing the state in which the valve cover is being removed from the valve body (first step of a three-part removal step) in a first mode in the step of removing the working valve from the housing. [Figure 33] FIG. 10 is a side cross-sectional view showing the state in which the valve body is removed from the valve box (the second step of the three-part removal step). [Figure 34] FIG. 10 is a side cross-sectional view showing the state in which the valve body is removed from the valve box (the second step of the three-part removal step). [Figure 35] FIG. 10 is a side cross-sectional view showing the state in which the valve body is removed from the valve box (the second step of the three-part removal step). [Figure 36] FIG. 10 is a side cross-sectional view showing the state in which the valve body is removed from the valve box (the second step of the three-part removal step). [Figure 37] FIG. 10 is a side cross-sectional view showing the valve box being removed from the housing (third step of the three-part removal process). [Figure 38] FIG. 10 is a side view showing the state after the working valve has been removed. [Figure 39] FIG. 10 is a side cross-sectional view showing the state in which the valve cover is removed from the valve body (first step of another three-part removal step) in a second mode in the step of removing the working valve from the housing. [Figure 40] FIG. 10 is a side cross-sectional view showing the removal of the valve body from the valve box (the second step of another three-part removal step). [Figure 41] FIG. 10 is a side cross-sectional view showing the removal of the valve body from the valve box (the second step of another three-part removal step). [Figure 42] FIG. 10 is a side cross-sectional view showing the removal of the valve body from the valve box (the second step of another three-part removal step). [Figure 43] FIG. 10 is a cross-sectional side view showing the removal of the valve body from the short pipe (the third step of another three-part removal process). [Figure 44] FIG. 10 is a side cross-sectional view showing the state in which the short tube is removed from the housing (fourth step of another three-part removal process). [Figure 45] FIG. 10 is a cross-sectional side view showing the state in which the valve body and valve cover are removed from the valve box (first step of the two-part removal step) in a third mode in the step of removing the operating valve from the housing. [Figure 46] FIG. 10 is a side cross-sectional view showing the state in which the valve body is removed from the housing (second step of the two-part removal step). [Figure 47] FIG. 10 is a side cross-sectional view showing the valve cover being removed from the valve body (first step of another two-part removal step) in a fourth mode in the step of removing the working valve from the housing. [Figure 48] FIG. 10 is a side cross-sectional view showing the removal of the valve body and valve disc from the short pipe (the second step of another two-part removal step). DETAILED DESCRIPTION OF THE INVENTION

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A description will now be given of an embodiment of the method for mounting an operating valve according to the present invention. [Example]

[0019] In the embodiment, the series of steps from cutting a predetermined portion of an existing fluid pipe 1 that constitutes a flow path component and installing a butterfly valve 10 (fluid control) at the cut portion, to the series of steps for removing the working valve 4 after the butterfly valve 10 (fluid control) has been installed, are explained with reference to Figures 1 to 48.

[0020] As shown in Fig. 1, excavation is performed around a predetermined location of a fluid pipe 1 buried underground, and a two-part housing 2 having a branch portion 2a opening upward is sealed around the fluid pipe 1. The fluid in the fluid pipe 1 may be, for example, tap water, industrial water, sewage, or a gas or a gas-liquid mixture of gas and liquid. Furthermore, although the housing 2 has a two-part structure in this embodiment, it may have a multi-part structure, and the divided housings may be joined together by welding or bolts via packing.

[0021] The fluid pipe 1 is a steel pipe formed into a generally circular cross section. The fluid pipe according to the present invention may be made of ductile cast iron, other cast iron, other metals, concrete, polyvinyl chloride, polyethylene, polyolefin, or the like. Furthermore, the inner circumferential surface of the fluid pipe may be coated with an epoxy resin layer, mortar, plating, or the like, or may be coated with an appropriate material by powder coating.

[0022] Furthermore, when the housing 2 is attached to the fluid pipe 1 in a sealed state, concrete foundations 9, 9 are formed below the housing 2 to support the weight around the housing 2 and prevent bending of the fluid pipe 1. Note that the foundations are not limited to the concrete foundations 9, 9, and jacks or the like may be used as long as they can support the weight of the housing 2 and the cutting machine 5 and valve introduction machine 6 described below.

[0023] Next, the process of attaching the operating valve 4, which can close the opening of the branch section 2a (opening), to the branch section 2a (opening) of the housing 2, will be described in order. The operating valve 4 of this embodiment is primarily composed of a valve box 41, a valve element 42, and a valve cover 43, as described below, and is a valve that can open and close the branch section 2a of the housing 2. First, the first step of the attachment process, in which the valve box 41 is installed in the branch section 2a (opening) of the housing 2, will be described. As shown in FIG. 1 , the valve box 41 constituting the operating valve 4 is suspended from above by a hoisting tool C equipped with a hook and a wire W, which are supported by a crane (not shown), and placed on the flange 2b of the branch section 2a. The position of the valve box 41 on the flange 2b is adjusted, and the flange 2b and the valve box 41 are fixed with bolts and nuts (not shown) (the first step of the attachment process is completed). Next, a plurality of valve element temporary supports 41b are attached to the lower lateral sides of the opening 41a of the valve box 41, spaced apart in the width direction. The valve disc temporary support 41b (mounting portion) has a vertical surface and a horizontal surface and forms a substantially right-angled triangle in a front view. The vertical surface abuts the lower end surface of the opening 41a of the valve box 41, and the horizontal surface extends from a slide groove 41e provided inside the valve box 41 and is attached to the opening 41a of the valve box 41 so as to be substantially flush with the surface of the slide groove 41e. The valve disc temporary support 41b may be attached to the valve box 41 after the valve box 41 is fixed to the branch portion 2a of the housing 2, as in this embodiment, or the valve box 41 may be fixed to the branch portion 2a of the housing 2 with the valve disc temporary support 41b attached to the valve box 41 in advance. The crane used in this embodiment is preferably a mobile rough terrain crane, and it goes without saying that it is made larger depending on its lifting capacity, and specifications capable of lifting the heaviest member of each member described below are selected while considering the allowable lifting load at the turning radius. Furthermore, the installation area of ​​the crane, including outriggers and the like, often requires an area larger than the excavation area of ​​the fluid pipe 1.

[0024] In this embodiment, even after the valve box 41 is placed on the flange 2b of the branch section 2a, the wire W is connected to the crane with the valve box 41 slightly loosened to ensure safety, but this is not limiting, and the hoisting tool C and the wire W may be removed from the valve box 41. Also, to make it easier to adjust the position of the valve box 41, the position may be adjusted relative to the flange 2b while the valve box 41 is slightly suspended by the crane.

[0025] The valve box 41 is generally cylindrical and extends vertically, with a slide groove 41e extending horizontally from an opening 41a on one side. The slide groove 41e guides the front and rear wheels 42c and 42d provided below the valve body 42, which will be described later. The weight of the valve box 41 in this embodiment is approximately 4,500 kg. An O-ring (not shown) is pressed between the flange 2b and the valve box 41, sealingly connecting the branch section 2a and the valve box 41. The weights of the components listed below are merely examples and can be changed as appropriate.

[0026] Next, the second step of the installation process for inserting the valve disc 42 into the valve box 41 will be described. As shown in Fig. 2, front eyebolts 42a serving as suspension supports are attached to the four corners of the upper part of the valve disc 42 constituting the working valve 4 at two locations on the front side (left side in the figure) in the insertion direction, and rear eyebolts 42b serving as suspension supports are attached to two locations on the rear side (right side in the figure) in the insertion direction. In addition, front wheels 42c and rear wheels 42d are attached to the bottom of the valve disc 42, and multiple side wheels 42i are attached to the sides. The front wheels 42c and rear wheels 42d are guided along slide grooves 41e provided in the valve box 41, and the multiple side wheels 42i are guided by abutting against the inner surface of the valve box 41, thereby allowing the valve disc 42 to be inserted and moved smoothly into the valve box 41. Next, the front wire W1 and the rear wire W2 are passed through the front eyebolt 42a and the rear eyebolt 42b, respectively. The valve disc 42 is lifted by the lifting tool C using the front wire W1 and the rear wire W2 so that it is horizontal, and then lowered to the side of the opening 41a of the valve box 41. The front wheel 42c of the valve disc 42 is then placed on the valve disc temporary support 41b attached to the side of the opening 41a of the valve box 41. Here, a chain block B is attached to the front wire W1 in advance, allowing the length of the front wire W1 to be extended or retracted. In FIG. 2, the lengths of the front wire W1 and the rear wire W2 are approximately the same, allowing the valve disc 42 to be stably suspended horizontally. Then, the front wheel 42c of the valve disc 42 is first placed on the valve disc temporary support 41b, and then a wheel chock 41c for the front wheel 42c of the valve disc 42 is inserted into the valve disc temporary support 41b to prevent the valve disc 42 from moving backward or falling.

[0027] In this way, when inserting the valve body 42 into the valve box 41, it can be placed and aligned on the valve body temporary support 41b (support portion) that protrudes into the opening 41a of the valve box 41, so that the valve body 42 can be inserted smoothly without colliding with the valve box 41.

[0028] Next, as shown in Figure 3, the length of the front wire W1 is adjusted in the extension direction using the chain block B attached to the front wire W1 until the rear wire W2 becomes approximately vertical. At this time, a crane is used to adjust so that the valve disc 42 always remains horizontal. Once the rear wire W2 becomes vertical and the front wire W1 has been confirmed to be loose, the front wire W1 and the front eyebolt 42a are removed from the valve disc 42. At this time, the front load of the valve disc 42 is supported by the valve disc temporary support base 41b, and the rear load of the valve disc 42 is suspended by the rear wire W2. Therefore, when the front eyebolt 42a is removed, the valve disc 42 does not move horizontally and can be maintained in a stable state.

[0029] Next, as shown in Figure 4(a), a retraction eyebolt 42e is attached to the upper part of the rear end of the valve disc 42, and the valve box 41 and valve disc 42 are connected by a valve disc retraction wire W3 and a chain block B'. ​​Then, in cooperation with the state in which the valve disc 42 is suspended by the wire W2, the length of the wire W3 is adjusted so that it is shortened by the chain block B' and retracted, and the valve disc 42 is gradually retracted horizontally into the valve box 41. After the rear wheel 42d of the valve disc 42 enters the valve box 41 and the valve disc 42 is retracted into the valve box 41 so that the rear end of the valve disc 42 is approximately 200 mm from the valve box mating flange surface, a valve disc removal prevention plate 41d serving as a restricting means for restricting the retraction of the valve disc 42 is attached to the opening 41a of the valve box 41 with a bolt, and the chain blocks B, B', wires W2, W3, rear eyebolt 42b, and retraction eyebolt 42e are removed. 4(b), the valve disc retaining plate 41d (restriction means) is a vertically long plate-like member attached to the end face of the opening 41a of the valve box 41, and blocks part (two places) of the opening 41a of the valve box 41 to prevent the valve disc 42 inserted into the valve box 41 from slipping out. Then, the rear end of the valve disc 42 is pushed completely into the valve box 41 using a crowbar or the like (not shown), and the valve disc temporary holder 41b is removed from the opening 41a of the valve box 41 (end of the second step of the installation process).

[0030] In this way, even if the eyebolt 42a (hanging support part) on the front side in the direction of travel of the valve body 42 is released, the load on the front side of the valve body 42 is supported near the opening 41a of the valve box 41, so the valve body 42 can be further inserted into the valve box 41 while maintaining an approximately parallel state similar to the state when it is hung and supported by a crane.

[0031] Next, the third step of the attachment process, which connects the valve disc 42 to the valve stem that serves as the operating part for moving the valve disc back and forth, will be described. As shown in Figure 5, the valve cover 43 is lifted horizontally using a wire W and a chain block B. A long feed screw 43a (valve stem) is installed horizontally inside the valve cover 43. This feed screw 43a is rotatable within the valve cover 43 and is journaled so that it cannot move axially back and forth. The tip of the feed screw 43a protrudes forward beyond the valve cover 43 and can be screwed into a feed nut 42f provided at the rear end of the valve disc 42 inserted into the valve box 41. The valve element 42 is suspended at a position where the tip of the feed screw 43a is axially aligned with the feed nut 42f provided at the rear end of the valve element 42, and the feed screw 43a inside the valve lid 43 is rotated at a slow speed using an electric screwdriver 43b attached to the rear end of the valve cover 43, and the tip of the feed screw 43a is screwed into the feed nut 42f inside the valve element 42, thereby connecting the valve element 42 and the feed screw 43a (end of the third step of the attachment process). Note that the feed screw 43a does not necessarily have to be turned using the electric screwdriver 43b, and it may also be turned manually using a handle or the like (not shown).

[0032] In this way, by attaching the rear end of the valve element 42 to the tip of the feed screw 43a (valve rod), the valve element 42 can be connected to an operating part for moving the valve element 42 back and forth.

[0033] Furthermore, as the feed nut 42f is gradually screwed from the tip of the feed screw 43a toward the base end (the right side in the figure), the tip opening of the valve cover 43 gradually approaches the opening 41a of the valve box 41. The crane is operated in cooperation with the speed of the feed screw, and the valve cover 43 is moved slowly toward the valve box 41 by operating the crane.

[0034] At this time, the valve body 42 inserted into the valve box 41 can be prevented from retracting and falling when connected to the feed screw 43a (operating part) for moving the valve body 42 forward and backward by the valve body removal prevention plate 41d (regulating means) that was previously installed.

[0035] 6 and 7 show a modified example in which the valve disc 42 and the feed screw 43a are connected. As in FIG. 5, a new wire W and a chain block B are used to lift the valve cover 43 so that it is horizontal. A long feed screw 43a (valve stem) is built into the valve cover 43, and a feed nut 42f' serving as a locked portion is threadedly engaged with the tip of the feed screw 43a. Meanwhile, as shown in FIG. 7, the valve disc 42 has a generally rectangular shape with a protruding rear end in a plan view. The rear end of the valve disc 42 is provided with a storage section 42g serving as a locking portion, with an open top, so that the feed nut 42f' can be accommodated therein and cannot rotate from above. A pair of nut retaining plates 42h are provided behind the storage section 42g, spaced apart from each other and open at the top, to prevent the feed nut 42f' from slipping out. The distance between the pair of nut retaining plates 42h is slightly larger than the diameter of the feed screw 43a and smaller than the width of the feed nut 42f'. 7, by inserting the feed screw 43a with the feed nut 42f' threaded onto its tip into the storage section 42g of the valve body 42, the front, rear, and side surfaces of the feed nut 42f' come into contact with the inner wall surface of the storage section 42g and the inner surface of the nut retaining plate 42h, preventing the feed nut 42f' from rotating, and the feed screw 43a continuous with the feed nut 42f' is sandwiched between the nut retaining plates 42h, restricting movement together with the feed nut 42f'. In this way, by hanging the valve cover 43 vertically from above using a crane, the feed nut 42f' threaded onto the tip of the feed screw 43a is fitted into the storage section 42g from above, connecting the valve body 42 and the feed screw 43a (end of the third step of the installation process in the modified example). Using an electric driver 43b, the feed screw 43a inside the valve cover 43 is rotated at a slow speed, and the crane is operated in cooperation with the speed of this feed screw, and the valve cover 43 is moved at a slow speed toward the valve box 41 by operating the crane.

[0036] In this way, the feed nut 42f' (engaged portion) threaded onto the feed screw 43a (valve stem) can be moved vertically to engage with the storage portion 42g (engaging portion) of the valve body 42, thereby making installation easy, as the feed screw 43a (valve stem) can be attached to the valve body 42.

[0037] Next, we will explain the fourth step of the installation process, which is to install the valve cover 43 on the valve box 41. As shown in Figure 8, the feed screw 43a is then rotated slowly using the electric driver 43b, and the valve cover 43 is pulled toward the valve box 41 by operating the crane, and when the gap between the mating flanges on the side ends of the valve box 41 and the valve cover 43 becomes small (for example, about 100 mm), the valve disc removal prevention plate 41d is removed.

[0038] Next, as shown in Figure 9, the valve cover 43 is pulled by rotating the feed screw 43a with the electric screwdriver 43b until the mating flanges at the side ends of the valve box 41 and the valve cover 43 are joined, and after the mating flanges at the side ends of the valve box 41 and the valve cover 43 are joined, they are fixed in place with bolts and nuts 44 (end of the fourth step of the installation process).

[0039] In this way, in the fourth step of the installation process, by operating the feed screw 43a (operating part) provided on the valve cover 43 with respect to the valve body 42 inserted into the valve box 41, the valve cover 43 can be brought closer to the valve box 41, and by working together with the lifting support provided by the crane, it is possible to easily connect the valve cover 43 and the valve box 41.

[0040] At this time, by performing the fourth installation step with the entire valve disc 42 inserted into the opening 41a of the valve box 41, the valve disc 42 is not exposed, making it easy to align the valve cover 43 when installing it on the valve box 41. This prevents the rear end of the valve disc 42 from coming into contact with the valve cover 43, avoiding damage to the rear end of the valve disc 42. Once the connection and fixation are confirmed, the wire W and chain block B that were holding the valve cover 43 are removed. Finally, the electric screwdriver 43b is used to rotate the lead screw 43a inside the valve cover 43, pulling the valve disc 42 inside the valve box 41 completely toward the valve cover 43, i.e., retracting the valve disc 42 to the "open" position.

[0041] As described above, the operating valve 4 is primarily composed of a first divided body comprising the valve box 41, a second divided body comprising the valve element 42, and a third divided body comprising the valve cover 43. These divided bodies are assembled in this order to form the operating valve 4 at the branch section 2a of the housing 2. In other words, because the first divided body, the second divided body, and the third divided body can be transported separately using the hoisting tool C and the wire W, the first divided body, the second divided body, and the third divided body can be transported with a good weight balance. Furthermore, compared to installing the operating valve 4 assembled at the branch section 2a (operating valve 4 with a total weight of 10,500 kg), the load on the crane can be distributed and reduced, allowing for a smaller crane and saving the work space required to install the operating valve 4. Furthermore, because the load on the hoisting tool C and the wire W is reduced, there is no need to prepare thicker hoisting tools C and wire W, and the costs of the hoisting tools C and wire W used can be reduced.

[0042] Furthermore, as will be described later, when a hole saw such as the cutter 52 of this embodiment is used as a means for cutting the fluid pipe 1, the hole saw will have a larger diameter than the outer diameter of the fluid pipe 1, and therefore the structure of the working valve 4 will also be larger. However, even in such cases, the first, second and third divisions can be transported separately using the lifting device C and wire W, so the crane can be suitably miniaturized.

[0043] Furthermore, the working valve 4 is composed of a valve box 41 installed above the branch section 2a, and a valve disc 42 and valve cover 43 that bulge out laterally from the valve box 41. After the valve box 41 is fixed to the branch section 2a, the valve disc 42 is inserted into the valve box 41, and then the valve cover 43 is fixed to the valve box 41. Therefore, when installing the valve box 41 in the branch section 2a, the weight balance will not cause the suspended load to tilt, making it easy to install the valve box 41 in the branch section 2a. Similarly, when connecting the valve cover 43 to the valve box 41, the weight balance will not cause the suspended load to tilt, making it easy to connect the valve cover 43 to the valve box 41.

[0044] Furthermore, when connecting the valve cover 43 to the valve box 41, the valve body 42 is inserted into the opening 41a of the valve box 41, and then the feed screw 43a of the valve cover 43 is screwed into the feed nut 42f of the valve body 42 inside the valve box 41, and the valve cover 43 can be guided and moved from the side until it abuts against the valve box 41, so that the valve cover 43 can be advanced and positioned accurately relative to the valve box 41.

[0045] In this embodiment, the valve cover 43 and the valve box 41 are fixed with bolts and nuts, but this is not limited to this. For example, they may be fixed with another fixing means such as a vice, or they may be fastened by welding or the like.

[0046] In this way, according to the installation method of the operating valve 4 of the present invention, the valve box 41, valve element 42, and valve cover 43 of the operating valve 4 are each separated, and the valve element 42 is first inserted into the valve box 41 installed in the housing 2, and then the valve cover 43 is attached to the valve box 41.Since the valve element 42 is inserted into the valve box 41 independently of the valve cover 43, the entire valve element 42 can be grasped and the posture of the valve element 42 can be controlled, allowing the valve element 42 to be inserted into the opening 41a of the valve box 41 with high precision.In addition, the risk of the valve element 42 coming into contact with the opening 41a of the valve box 41 is reduced, so the valve element 42 is not damaged and the sealing properties of the operating valve 4 itself can be maintained. Furthermore, the operating valve 4 is divided into the valve box 41, valve body 42, and valve cover 43, which are lifted and transported individually by a crane, so the weight of each component to be lifted by the crane is small and a small crane can be used, allowing work to be carried out even in situations where there is not enough work space; and since the individual components are small in weight, handling is improved and the difficulty of attaching the operating valve 4 to the housing 2 is reduced.

[0047] Next, a process for installing a cutting machine 5 for cutting the fluid pipe 1 above the working valve 4 will be described. As shown in Figure 10, first, a mounting flange cylinder 51 (cylindrical body) that penetrates vertically is suspended by a hoisting tool C and a wire W and lowered to above the valve box 41, and the mounting flange cylinder 51 is then fixed above the valve box 41 with bolts and nuts (not shown). In this embodiment, the weight of the mounting flange cylinder 51 is approximately 2600 kg. An O-ring (not shown) is pressed between the mounting flange cylinder 51 and the valve box 41, so that the valve box 41 and the mounting flange cylinder 51 are connected in a hermetic manner.

[0048] Next, as shown in Figure 11, the cutter 52 is temporarily installed on the mounting flange tube 51. More specifically, with the cover 53 of the mounting flange tube 51 connected to the top of the cutter 52, it is suspended by a hoist C and a wire W and lowered to above the mounting flange tube 51. The cutter 52 comprises a cylindrical member 52a equipped with a cutting blade at its peripheral end, and a center drill 52b disposed coaxially with the cylindrical member 52a and protruding beyond the boring blade, with the cylindrical member 52a and the center drill 52b being fixed in place. An adapter 54, with an annular protrusion 54a formed at its upper end, is attached above the cylindrical member 52a and the center drill 52b so as not to rotate relative to each other.

[0049] The cover 53 has a through hole 53a formed in the center thereof, penetrating in the up-down direction, through which an adapter 54 is inserted. The cover 53 also has a plurality of recesses 53b formed in the circumferential direction, recessed from the inner peripheral surface of the through hole 53a in the outer radial direction, and a fixing jig 55, which can advance and retreat in the radial direction of the through hole 53a, is disposed in the recesses 53b. The fixing jig 55 protrudes in the inner radial direction of the through hole 53a and engages with the underside of the annular protrusion 54a of the adapter 54, thereby integrating the cutter 52 and the cover 53.

[0050] In this embodiment, the weight of the cutter 52 is approximately 2910 kg, the weight of the lid body 53 is approximately 1900 kg, and the weight of the adapter 54 is approximately 290 kg, with the total weight being approximately 5100 kg.

[0051] 12, with the lid 53 placed on top of the mounting flange cylinder 51, the mounting flange cylinder 51 and the lid 53 are aligned and fixed together with bolts and nuts (not shown). At this time, the cutter 52 is housed inside the mounting flange cylinder 51.

[0052] 12, the packing S2 is pressed in the circumferential direction between the cylindrical mounting flange 51 and the lid 53, ensuring a tight seal between the cylindrical mounting flange 51 and the lid 53. While this embodiment has been described with an example in which the packing S2 is press-fitted into a groove provided on the lid 53 side, the present invention is not limited to this, and a groove may be provided on the cylindrical mounting flange 51 side, and the packing S2 may be press-fitted into this groove.

[0053] Next, the drive mechanism 8 (drive unit) of the cutting machine 5 is connected to the cutter 52. First, the structure of the drive mechanism 8 will be described with reference to FIG.

[0054] 13, the drive mechanism 8 is mainly composed of a shaft member 81, a gripping member 82 capable of gripping or releasing the grip of the shaft member 81, an advancing / retreating member 83 for moving the gripping member 82 back and forth within the axial range of the shaft member 81, a restricting member 84 capable of restricting or releasing the movement of the shaft member 81 at a position below the advancing / retreating member 83, and a base member 85 to which the advancing / retreating member 83 and the restricting member 84 are attached. The weight of the drive mechanism 8 in this embodiment is approximately 6,060 kg.

[0055] A rotary motor 87 is fixed to a part of the advancing / retreating member 83, and the rotary motor 87 applies a rotational force to the gripping member 82 that is gripping the shaft member 81, thereby transmitting rotation to the shaft member 81, and the rotation of the shaft member 81 causes the cutter 52 to rotate. Note that by providing multiple shaft members 81, it is possible to extend the axial length by adding more shaft members 81 in the axial direction, and this extension structure makes it possible to reduce weight and height.

[0056] 14, when connecting the drive mechanism 8 to the cutter 52, a plurality of jacks 7 (spacers) are arranged in the circumferential direction of the upper flange 53c of the cover body 53, and the shaft member 81 is advanced downward in advance by a predetermined distance until the lower end of the shaft member 81 protrudes downward beyond the case part 86. The drive mechanism 8 is then suspended by the hoisting tool C and wire W, and the case part 86 is placed on the jacks 7. Next, an operator accesses the gap formed by the jacks 7 between the case part 86 and the upper flange 53c of the cover body 53, and connects the shaft member 81 to the adapter 54 with bolts and nuts N1.

[0057] 15, the drive mechanism 8, adapter 54, and cutter 52 are lifted slightly upward by a crane, the jack 7 is removed from between the case portion 86 and the cover 53, and the fixing jig 55 is retracted into the recess 53b. At this time, the cutter 52 (approximately 2,910 kg), adapter 54 (approximately 290 kg), and drive mechanism 8 (approximately 6,060 kg) are lifted by the crane, so the weight on the crane is approximately 9,260 kg. At this time, a plurality of jacks 7 (spacers) may be arranged in the circumferential direction of the lower flange 53d of the cover 53, and the drive mechanism 8 may be placed on the jacks 7 to support its weight, thereby reducing the weight on the crane.

[0058] 16, the drive mechanism 8 is lowered using a crane so that the case 86 is placed on the upper flange 53c of the lid 53, and the case 86 and the lid 53 are fixed together with bolts and nuts (not shown). As a result, the mounting flange tube 51, cutter 52, lid 53, adapter 54, and drive mechanism 8 constitute the cutting machine 5, and the housing 2, work valve 4, and cutter 5 constitute the cutting device. At this time, it goes without saying that the center drill 52b is adjusted so as not to come into contact with the valve body 42.

[0059] Next, the process of cutting the fluid pipe 1 using the cutting machine 5 will be described. As shown in Figure 17, first, the valve element 42 of the working valve 4 is retracted to open the branch portion 2a, and the outer peripheral surface of the rear end side of the shaft member 81 is gripped by the gripping member 82 described above. Next, the rotary motor 87 is driven to rotate the shaft member 81 and the cutter 52. Then, with the shaft member 81 and the cutter 52 rotated, the advancing and retracting member 83 is advanced toward the fluid pipe 1. As a result, first, the center drill 52b of the cutter 52 drills the pipe wall of the fluid pipe 1.

[0060] 18, when the fluid pipe 1 is cut by the cutter 52, the piece 1a formed by cutting the fluid pipe 1 is held within the cylindrical member 52a. Then, by moving the shaft member 81 and the cutter 52 backward in the reverse order of the above steps, the piece 1a is pulled up into the mounting flange cylinder 51, and the branch portion 2a is closed by the valve body 42 of the working valve 4, thereby completing the cutting operation of the fluid pipe 1.

[0061] Next, the process of installing the valve introducer 6 for installing the butterfly valve 10 at the cut location of the fluid pipe 1 will be described. As shown in FIG. 19, first, with the branch section 2a closed by the valve body 42 of the operating valve 4, a cylindrical member 61 (cylindrical body) penetrating in the vertical direction is suspended by a hoisting tool C and a wire W and lowered to above the operating valve 4, and the cylindrical member 61 is fixed above the operating valve 4 with bolts and nuts (not shown). In this embodiment, the weight of the cylindrical member 61 is approximately 3000 kg. An O-ring (not shown) is pressed between the cylindrical member 61 and the operating valve 4 (valve box 41), so that the cylindrical member 61 and the operating valve 4 are connected in a hermetic manner.

[0062] Next, a description will be given of the process of temporarily installing the butterfly valve 10 in the cylindrical member 61. First, the structure of the butterfly valve 10 will be described with reference to FIG.

[0063] As shown in FIG. 21, the butterfly valve 10 controls the flow path of the fluid pipe 1 between a fluid-passable state and a fluid-blocking state. It comprises a partition wall 11 with an opening approximately in the center, an opening / closing shaft 12 rotatably attached to the upper end of the partition wall 11, a valve element 13 that rotates around the opening / closing shaft 12 to open and close the opening in the partition wall 11, and a substantially horizontally extending, generally circular, upper cover 14 (cover body) that is hermetically sealed to the upper end of the partition wall 11. Gaskets S5 are secured to both side and bottom surfaces of the partition wall 11, and gasket S6 is secured to the entire outer periphery of the upper cover 14, with the gaskets S5 and S6 connected together. The total weight of the butterfly valve 10 in this embodiment is approximately 9,540 kg. Needless to say, a packing or similar seal is provided between the partition wall 11 and the upper cover 14.

[0064] 20, when temporarily installing the butterfly valve 10 in the cylindrical member 61, first, the partition wall 11, the opening / closing shaft 12, and the valve element 13 (main body) are suspended as a unit by a suspender C and a wire W and lowered to a position where they will be housed inside the cylindrical member 61. At this time, the valve element 13 is positioned so that it is approximately parallel to the pipe axis direction (with the opening of the partition wall 11 open).

[0065] Then, a locking member 62 (locking portion, holding portion) is inserted from the outside through a plurality of windows 61a formed around the circumference of the cylindrical member 61 so that it partially protrudes into the cylindrical member 61. As a result, the protruding piece 11a protruding outward from the partition wall 11 is placed (locked) on the tip portion of the locking member 62, and the partition wall 11, the opening / closing shaft 12, and the valve body 13 are held by the cylindrical member 61. Note that a recess 62a capable of accommodating part of the valve body 13 is formed in the lower part of the tip side of the locking member 62, so that the locking member 62 and the valve body 13 do not interfere with each other.

[0066] 21, the upper cover 14 is suspended by a suspender C and a wire W, and placed on top of the partition wall 11 with the opening / closing shaft 12 inserted therethrough. The upper cover 14 and the partition wall 11 are then hermetically connected by a fixing means (not shown), thereby completing the butterfly valve 10.

[0067] 22, the mounting flange tube 63, which penetrates vertically, is suspended by a suspender C and a wire W and lowered to above the cylindrical member 61, and the mounting flange tube 63 is fixed to the top of the cylindrical member 61 with bolts and nuts (not shown). The weight of the mounting flange tube 63 in this embodiment is approximately 2600 kg.

[0068] 22, an annular groove 63a is formed on the underside of the cylindrical mounting flange 63, and an annular gasket S7 is press-fitted into the annular groove 63a. When the cylindrical member 61 and the cylindrical mounting flange 63 are fixed together, the gasket S7 is pressed between the cylindrical member 61 and the cylindrical mounting flange 63, ensuring a tight seal between the cylindrical member 61 and the cylindrical mounting flange 63. Note that while this embodiment has exemplified a form in which the gasket S7 is press-fitted into the annular groove 63a formed on the underside of the cylindrical mounting flange 63, this is not limiting, and an annular groove may be provided on the cylindrical member 61 side, and the gasket S7 may be press-fitted into the annular groove.

[0069] Next, as shown in Figure 23, a valve hanger 64, which will be connected to the butterfly valve 10, is temporarily installed on the mounting flange tube 63. Specifically, with the cover 65 of the mounting flange tube 63 connected to the top of the valve hanger 64, it is suspended by a hanger C and a wire W and lowered to above the mounting flange tube 63. The valve hanger 64 has a mounting surface 64a facing substantially horizontally, a cylindrical shaft 64c extending upward from a through hole 64b located approximately in the center of the mounting surface 64a, and a reinforcing rib 64d provided between the mounting surface 64a and the shaft 64c. An adapter 66 is connected to the upper end of the shaft 64c.

[0070] The lid 65 has a through hole 65a formed in the center thereof that penetrates vertically, and an adapter 66 is inserted into the through hole 65a. The lid 65 also has a plurality of recesses 65b formed in the circumferential direction, recessed radially outward from the inner peripheral surface of the through hole 65a, and a fixing jig 67 that can advance and retreat radially through the through hole 65a is disposed in the recesses 65b. The fixing jig 67 protrudes radially inward from the through hole 65a and engages with the underside of the annular protrusion 66a of the adapter 66, thereby integrating the valve hanger 64 and the lid 65.

[0071] As shown in Figure 24, with the lid 65 placed on the upper end of the mounting flange cylinder 63, the mounting flange cylinder 63 and the lid 65 are aligned and fixed with bolts and nuts (not shown). In this embodiment, even after the lid 65 is placed on the mounting flange cylinder 63, the lid 65 is connected to the crane with the wire W slightly loosened to ensure safety, but this is not limited to this, and the hoisting tool C and the wire W may be removed from the lid 65. Furthermore, to make it easier to adjust the position of the lid 65, the position of the mounting flange cylinder 63 and the lid 65 may be adjusted with the lid 65 slightly suspended by the crane.

[0072] 24, the packing S8 is pressed in the circumferential direction between the cylindrical mounting flange 63 and the lid 65, ensuring a tight seal between the cylindrical mounting flange 63 and the lid 65. Note that, although this embodiment has exemplified a form in which the packing S8 is press-fitted into a groove provided on the lid 65 side, the present invention is not limited to this, and a groove may be provided on the cylindrical mounting flange 63 side, and the packing S8 may be press-fitted into this groove.

[0073] Next, the drive mechanism 8, which serves as the insertion device for the valve introducer 6, is connected to the valve hanger 64. Note that the drive mechanism 8 is the same as the one used when cutting the fluid pipe 1, so a description of the structure of the drive mechanism 8 will be omitted.

[0074] 25, when connecting the drive mechanism 8 to the valve hanging fitting 64, the shaft member 81 is advanced downward in advance by a predetermined distance so that the lower end of the shaft member 81 protrudes downward beyond the case portion 86, and multiple jacks 7 (spacers) are placed circumferentially around the upper flange 65c of the lid body 65. The drive mechanism 8 is then suspended by a crane, and the case portion 86 is placed on the jacks 7. Next, an operator accesses the gap formed by the jacks 7 between the case portion 86 and the upper flange 65c of the lid body 65, and connects the shaft member 81 and the adapter 66 with bolts and nuts N2.

[0075] 26, the drive mechanism 8, adapter 66, and valve hoisting fixture 64 are lifted slightly upward by a crane, the jack 7 is removed from between the case 86 and the cover 65, and the fixing jig 67 is retracted into the recess 65b. At this time, the valve hoisting fixture 64 (approximately 2000 kg), the adapter 66 (approximately 270 kg), and drive mechanism 8 (approximately 6060 kg) are lifted by the hoisting fixture C and wire W, so the weight applied to the hoisting fixture C and wire W is approximately 8330 kg. At this time, a plurality of jacks 7 (spacers) may be arranged circumferentially around the lower flange 65d of the cover 65, and the drive mechanism 8 may be placed on the jacks 7 to support its weight, thereby reducing the weight applied to the crane.

[0076] 27, the valve hanger 64 is lowered by the drive mechanism 8, and the mounting surface 64a of the valve hanger 64 is connected to the upper cover 14 of the butterfly valve 10 with bolts and nuts (not shown). As a result, the cylindrical member 61, mounting flange 63, valve hanger 64, cover 65, adapter 66, and drive mechanism 8 constitute the valve introducer 6, and the housing 2, working valve 4, and valve introducer 6 constitute the valve installation device. At this time, the opening / closing shaft 12 of the butterfly valve 10 is inserted into the shaft 64c of the valve hanger 64.

[0077] Thereafter, the valve suspender 64 and butterfly valve 10 are lifted slightly upward by the drive mechanism 8, and the locking member 62 is retracted and pulled out of the window 61a of the cylindrical member 61. Although not shown, the window 61a is plugged to seal it. At this time, it goes without saying that the lower end of the butterfly valve 10 is adjusted so that it does not come into contact with the valve disc 42.

[0078] Next, a process for installing the butterfly valve 10 at the section of the fluid pipe 1 cut by the valve introducer 6 will be described. As shown in Figure 28, the valve element 42 of the working valve 4 is retracted to open the branch section 2a, and the outer peripheral surface of the rear end side of the shaft member 81 is gripped by the gripping member 82 described above. Then, the advancing / retracting member 83 is slid toward the fluid pipe 1, thereby advancing the shaft member 81 and the butterfly valve 10 toward the fluid pipe 1.

[0079] The shaft member 81 and butterfly valve 10 move forward within a range from the position where the gripping member 82 grips the shaft member 81 to a position close to the restricting member 84, and after the forward movement is complete, the movement of the shaft member 81 and butterfly valve 10 is restricted by the restricting member 84. Thereafter, another shaft member 81', 81' is connected to the upper end of the shaft member 81, and the above process is repeated to position the butterfly valve 10 at the cut portion of the fluid pipe 1. After the butterfly valve 10 has been placed at the cut portion of the fluid pipe 1, as shown in FIG. 29, the butterfly valve 10 is fixed to the housing 2 by a predetermined retaining means 15. At this time, it is not necessary to connect another shaft member 81'; positioning may be completed using a shaft member 81 of a predetermined length in advance.

[0080] With regard to the restraining means 15 in detail, the restraining means 15 is mainly composed of a through-hole having an internal thread that penetrates the peripheral wall of the housing 2, and a bolt-like member that is inserted into the through-hole and screwed into the internal thread, with multiple through-holes and bolt-like members evenly spaced in the circumferential direction. By rotating the bolt-like member in a predetermined direction, it is advanced toward the inner diameter of the housing 2 and positioned above the corner of the top cover 14 of the butterfly valve 10. The tip of the bolt-like member abuts against the upper surface of the corner of the top cover 14, thereby preventing the butterfly valve 10 from coming off. The restraining means may be separate entities, with the advancement means that is screwed into the internal thread of the through-hole and the abutment means that abuts against the fluid valve, and the number and arrangement of these entities may be changed as appropriate.

[0081] Furthermore, when the butterfly valve 10 is fixed to the housing 2, the gasket S5 of the partition wall 11 is pressed against both inner surfaces and the inner bottom surface of the housing 2, and the gasket S6 of the upper cover portion 14 is pressed against the inner surface of the branch portion 2a, thereby preventing the fluid flowing through the fluid pipe 1 from leaking between the partition wall 11 and the housing 2 and preventing the fluid from leaking from the branch portion 2a.

[0082] 29, the fluid inside the cylindrical member 61 and the mounting flange tube 63 is discharged to the outside, and the bolt and nut connection between the mounting surface 64a of the valve hanger 64 and the top cover 14 of the butterfly valve 10 is released through the working hole 61b of the cylindrical member 61. Then, the shaft member 81 is moved backward in the reverse order of the above steps, and the valve hanger 64 is pulled up into the cylindrical member 61 and the mounting flange tube 63, completing the installation of the butterfly valve 10 at the cut location of the fluid pipe 1.

[0083] In the above embodiment, the cutter 52 is a hole saw composed of a cylindrical member 52a and a center drill 52b, but the present invention is not limited to this and can be freely modified. For example, as shown in Figure 30, a cutting machine 500 in a modified example is composed of a cutter mechanism 501 fitted onto a predetermined position of the fluid pipe 1 inside the housing 20, a work case 502 attached above the work valve 402, and a drive mechanism 800 that drives the cutter mechanism 501 and can lift it into the work case 502.

[0084] Cutter mechanism 501 includes two sprockets 501a, 501a rotatably mounted in the outer circumferential direction of fluid pipe 1, and a drive transmission unit 501b that transmits driving force to sprockets 501a, 501a, and cutting tools (not shown) that cut fluid pipe 1 are attached to sprockets 501a, 501a. Drive mechanism 800 also includes a rod 801 connected to drive transmission unit 501b, a motor 802 that drives rod 801 to rotate, and a lifting mechanism 803 that can lift rod 801.

[0085] By driving the motor 802, the sprockets 501a, 501a rotate via the rod 801 and the drive transmission unit 501b, thereby cutting the fluid pipe 1. In addition, the cutter mechanism 501 can be pulled up into the work case 502 by the lifting mechanism 803 while the sprockets 501a, 501a are still holding the cut piece of the fluid pipe 1.

[0086] Next, the process for removing the working valve 4 will be described below. As shown in Figure 31, the fluid inside the cylindrical member 61 and the mounting flange tube 63 is discharged to the outside, and once it has been confirmed that the branch portion 2a of the housing 2 has been watertight by the butterfly valve 10, the valve introducer 6 is removed from the working valve 4, and the working valve 4 is then removed from the branch portion 2a (see Figure 32 onwards).

[0087] When removing the valve introducer 6, the work is performed in substantially the reverse order of the procedure for assembling the valve introducer 6. Briefly, from the state shown in FIG. 29, the drive mechanism 8, adapter 66, and valve hoisting bracket 64 are lifted slightly upward using the lifting tool C and wire W, and the case portion 86 is placed on a plurality of jacks 7 arranged circumferentially around the upper flange 65c of the cover body 65 (see FIG. 25). Next, the fixing jig 67 is engaged with the adapter 66 (see FIG. 23). The drive mechanism 8, which has been released from fastening to the adapter 66 by the bolts and nuts N2, is lifted and removed using the lifting tool C and wire W through the gap between the case portion 86 and the upper flange 65c (see FIG. 24). Furthermore, the fastening between the mounting flange tube 63 and the cover body 65 by the bolts and nuts, etc., is released, and the valve hoisting bracket 64, cover body 65, and adapter 66 are lifted and removed using the lifting tool C and wire W (see FIG. 23). Then, the mounting flange tube 63, which has been released from its fastening to the cylindrical member 61 by bolts and nuts, etc., is lifted and removed using the lifting tool C and wire W, and then the cylindrical member 61, which has been released from its fastening to the operating valve 4 by bolts and nuts, etc., is lifted and removed using the lifting tool C and wire W (see Figure 19).

[0088] [3-part removal process] Next, we will explain the process of removing the working valve 4 from the branching portion 2a of the housing 2. First, we will explain the three-part removal process. The three-part removal process consists of a first step of removing the valve cover 43 from the valve box 41 that contains at least a part of the valve body 42, a second step of extracting and removing the valve body 42 from the valve box 41, and a third step of removing the valve box 41 from the branching portion 2a.

[0089] First, the first step of the three-piece removal process will be described. As shown in FIG. 32, the lead screw 43a is rotated with an electric screwdriver 43b to advance the valve disc 42 into the valve box 41. The front end of the valve disc 42 is then connected to the valve box 41 through an upper opening of the valve box 41 with a wire W4 and a chain block B1, which serve as a restricting means for the insertion direction. At this time, the length of the wire W4 is adjusted with the chain block B1 so as to restrict the valve disc 42 from contacting the opening / closing shaft 12 of the butterfly valve 10 located inside the valve box 41. This prevents damage to the valve disc 42 due to contact with the opening / closing shaft 12 and leakage from the branch portion 2a of the housing 2. Note that the restricting means for the insertion direction is not limited to the wire W4 and the chain block B1. For example, it may be a rod-like or string-like member that is adjustable to a predetermined length and has a locking portion that can be locked to the housing 2 or the valve disc 42, or may be modified as appropriate.

[0090] Once the valve body 42 has advanced to the vicinity of the opening / closing axis 12, a lifting device C, a wire W and a chain block B are attached to the valve cover 43, and the length of the wire W is adjusted with the chain block B so that the valve cover 43, now released from its connection to the valve box 41, can be suspended horizontally in the same manner as before it was released, and the fastening of the mating flanges at the side ends of the valve box 41 and the valve cover 43 using bolts and nuts 44 (see Figure 9) is released.

[0091] Next, the valve cover 43 is pulled away from the valve box 41 by operating the crane, while the lead screw 43a is rotated with the electric screwdriver 43b to maintain the position of the valve disc 42. When the rear end of the valve disc 42 is exposed outside the valve cover 43, an eyebolt 42j is attached to the rear end, and the valve box 41 and the valve disc 42 are connected with the wire W5 and chain block B2, which serve as a means for restricting the valve disc 42 in the removal direction. Then, when a portion of the valve disc 42 is housed within the valve box 41 and the remainder is exposed outside the valve box 41, the length of the wire W5 is adjusted with the chain block B2 to prevent the valve disc 42 from tilting or unintentionally coming out of the valve box 41. This allows for easy and safe operation. The means for restricting the removal direction is not limited to the wire W5 and the chain block B2. For example, the means for restricting the removal direction may be a rod- or string-like member that can be adjusted to a predetermined length and has a locking portion that can be locked to the housing 2 or the valve disc 42, or may be modified as appropriate.

[0092] Furthermore, while the crane is used to pull the valve cover 43 in a direction away from the valve box 41, the electric screwdriver 43b is used to rotate the feed screw 43a, and the tip of the feed screw 43a is released from the feed nut 42f inside the valve body 42. Then, as shown in Figure 33, the valve cover 43 is removed (the first step of the three-part removal process is completed).

[0093] Next, the second step of the three-part removal process will be described. As shown in Figure 33, a plurality of valve body temporary holders 41b are attached to the opening 41a of the valve box 41, and wheel chocks 41c are inserted into the valve body temporary holders 41b.

[0094] As shown in Figure 34, the rear wire W2 is passed through the rear eyebolts 42b provided at two locations on the rear side of the upper part of the valve body 42 in the insertion direction (right side in the figure), and the rear wire W2 is lifted up with the lifting tool C so that the valve body 42 is horizontal, and the wires W4, W5 and the chain blocks B1, B2 are removed.

[0095] Thereafter, the crane is operated to move the valve disc 42 substantially horizontally in a direction away from the valve box 41, i.e., in the direction of removal. At this time, the front wheel 42c of the valve disc 42 is guided along the slide groove 41e provided in the valve box 41, and the multiple side wheels 42i are guided by contacting the inner surface of the valve box 41, thereby allowing the valve disc 42 to be smoothly removed from the valve box 41 and moved.

[0096] As shown in Figure 35, the valve disc 42 is moved horizontally in the removal direction to a position where the front eyebolt 42a can be attached. At this time, the front wheel 42c of the valve disc 42 is moved outside the valve box 41 and onto the multiple valve disc temporary holders 41b, so the valve disc 42 is held at the same height as when it was inserted into the valve box 41. This prevents a sudden load from being applied to the crane. Furthermore, by moving the valve disc 42 until its movement is restricted by the wheel stopper 41c, not only is removal of the valve disc 42 prevented, but the valve disc 42 can also be positioned at a position where the front eyebolt 42a can be attached. In other words, it is easy to align the valve disc 42 to a position where the front eyebolt 42a can be attached.

[0097] Then, front eyebolts 42a are provided at two locations on the front side in the insertion direction (left side in the figure) of the upper part of the valve body 42, and the front wire W1 is passed through them. The length of the front wire W1 is adjusted with the chain block B, and the crane is operated to horizontally suspend the valve body 42 by the front wire W1 and rear wire W2. In Figure 35, the length of the front wire W1 and the length of the rear wire W2 are approximately the same, so the valve body 42 can be stably suspended horizontally.

[0098] As shown in Figure 36, the wheel stopper 41c is removed, and the valve body 42 is moved horizontally away from the valve box 41 using a crane, and the valve body 42 is removed from the valve box 41 (end of the second step of the three-part removal process).

[0099] Next, the third step of the three-piece removal process will be described. As shown in Figure 37, the valve body temporary support 41b is removed, a hoisting tool C and a wire W are attached to the valve box 41, and the valve box 41, which has been released from the fastening of the flange 2b of the branch portion 2a with the bolts and nuts, is removed by a crane (end of the third step of the three-piece removal process).

[0100] 38, an annular reinforcing element 16 is fixed to the flange 2b with bolts and nuts (not shown). When the reinforcing element 16 is fixed to the flange 2b, the annular protrusion extending in the axial direction abuts against the upper cover portion 14 of the butterfly valve 10, thereby reinforcing the butterfly valve 10 to prevent it from coming loose.

[0101] As described above, in the three-division removal process, the work valve 4 is separated into a first divided body consisting of the valve cover 43, a second divided body consisting of the valve body 42, and a third divided body consisting of the valve box 41, and these are removed in order from the branching section 2a of the housing 2, thereby making it possible to remove the work valve 4. This distributes and reduces the weight load on the crane compared to removing the work valve 4 in its assembled state from the branching section 2a (work valve 4 with a total weight of 10,500 kg) or removing a work valve 4 made up of multiple components by dividing it into a number less than the number of components (for example, if it has three components, dividing it into two divided bodies for removal), which allows the crane to be made smaller and saves the work space required to remove the work valve 4.

[0102] Furthermore, when assembling the operating valve 4, the first divided body consisting of the valve cover 43, the second divided body consisting of the valve body 42, and the third divided body consisting of the valve body 41 are transported separately, and when removing the operating valve 4, the first divided body consisting of the valve cover 43, the second divided body consisting of the valve body 42, and the third divided body consisting of the valve body 41 are transported separately. In other words, because the divided bodies used when assembling the operating valve 4 and the divided bodies used when removing the operating valve are the same, it is possible to use the same crane and perform the work in the same work space when assembling and removing the operating valve 4, thereby reducing the work effort and the costs of arranging multiple cranes, etc.

[0103] 6 and 7, in the case of the modified example in which the valve element 42 and the lead screw 43a are connected, the connection between the valve element 42 and the valve cover 43 can be released by pulling out the feed nut 42f' threaded onto the tip of the lead screw 43a upward from the storage portion 42g of the valve element 42. The other procedures are the same as those described above.

[0104] [Other 3-part removal process] Next, we will explain another three-part removal process, which is a process for removing the working valve 4 and the short pipe 45 from the branching portion 2a of the housing 2. The other three-part removal process consists of a first step of removing the valve cover 43 from the valve box 41 in which the valve body 42 is housed, a second step of extracting the valve body 42 from the valve box 41, a third step of removing the valve box 41 from the short pipe 45, and a fourth step of removing the short pipe 45 from the branching portion 2a.

[0105] The short pipe 45 is a pipe member attached between the flange 2b of the branch section 2a and the valve box 41. By placing the operating valve 4 on the short pipe 45, the valve element 42 can move above the opening / closing shaft 12 of the butterfly valve 10, thereby preventing contact between the opening / closing shaft 12 and the valve element 42. Furthermore, explanations that overlap with the three-part removal process described above will be simplified.

[0106] First, the first step of the other three-piece removal process will be described. As shown in Figure 39, the lead screw 43a is rotated with an electric screwdriver 43b to advance the valve disc 42 all the way into the valve box 41. In other words, the entire valve disc 42 is housed inside the valve box 41. Then, a lifting tool C, a wire W, and a chain block B are attached to the valve cover 43, and the mating flanges at the side ends of the valve box 41 and the valve cover 43 are released from the bolts and nuts 44 (see Figure 9). The valve cover 43, now released from the valve box 41, is suspended horizontally in the same manner as before the release.

[0107] Next, while pulling the valve cover 43 in a direction away from the valve box 41, the lead screw 43a is rotated with an electric screwdriver 43b (see Figure 32) to hold the position of the valve disc 42. Then, the valve disc retaining plate 41d is attached to the opening 41a of the valve box 41 with a bolt through the gap (for example, about 100 mm) between the mating flanges of the side ends of the valve box 41 and the valve cover 43.

[0108] Furthermore, the electric screwdriver 43b is used to rotate the lead screw 43a, disengaging the tip of the lead screw 43a from the lead nut 42f inside the valve body 42, and the valve cover 43 is removed as shown in Figure 40 (the first step of the other three-part removal process is completed).

[0109] Next, the second step of the other three-part removal process will be described. Referring to FIG. 39, first, the valve element 42 is pressed in the removal direction with a crowbar or the like through the opening of the branch portion 2a of the housing 2. At this time, the front wheel 42c and multiple side wheels 42i of the valve element 42 allow the valve element 42 to be moved manually. Furthermore, by moving the valve element 42 until it abuts against the valve element retaining plate 41d, not only is removal prevented but the valve element 42 can also be positioned so that the rear eyebolt 42b can be attached. The position of the valve element 42 does not need to be abutted against the valve element retaining plate 41d, and this may be changed as appropriate.

[0110] The rear wire W2 is passed through the rear eyebolt 42b provided on the valve disc 42, and the valve disc 42 is lifted up with the lifting tool C so that it is horizontal. Then, as shown in Figure 40, the valve disc retaining plate 41d is removed, multiple valve disc temporary holders 41b are attached to the opening 41a of the valve box 41, and wheel chocks 41c are inserted into the valve disc temporary holders 41b. After that, the crane is operated to move the valve disc 42 in the removal direction.

[0111] As shown in Figure 41, the valve disc 42 is moved to a position where the front eyebolt 42a can be attached, the front eyebolt 42a is attached to the valve disc 42, the front wire W1 is passed through it, and the valve disc 42 is suspended horizontally by the front wire W1 and the rear wire W2. Then, the wheel stopper 41c is removed, and the valve disc 42 is moved horizontally away from the valve box 41 by operating the crane, and the valve disc 42 is removed from the valve box 41 as shown in Figure 42 (end of the second step of the other three-part removal process).

[0112] Next, the third step of the other three-piece removal process will be described. As shown in Figure 43, the valve body temporary support 41b is removed, a hoisting tool C and a wire W are attached to the valve box 41, and the valve box 41, which has been released from the fastening to the flange of the short pipe 45 with bolts and nuts, is removed by a crane (end of the third step of the other three-piece removal process).

[0113] Next, the fourth step of the other three-piece removal process will be described. As shown in Figure 44, a hoisting tool C and a wire W are attached to short pipe 45, and short pipe 45, which has been released from the fastening of flange 2b of branch portion 2a with bolts and nuts, is removed by a crane (completion of the fourth step of the other three-piece removal process). Thereafter, as shown in Figure 38, reinforcing tool 16 is fixed to flange 2b with bolts and nuts (not shown).

[0114] In this way, short pipe 45 is arranged between branch portion 2a of housing 2 and working valve 4 as contact prevention means for preventing valve element 42, which is the second divided body, from contacting butterfly valve 10, which is a fluid valve, so working valve 4 can be removed in substantially the reverse order of the procedure used when assembling working valve 4. This allows the same equipment to be used when assembling and removing working valve 4, simplifying the work and reducing costs associated with the work.

[0115] It is also possible to omit the fourth step of the other three-part removal process described above, and in the preceding third step, remove the valve box 41 together with the short pipe 45 connected to the valve box 41 using a crane.

[0116] Furthermore, the contact prevention means is not limited to the short pipe 45, but may be modified as appropriate, for example by lengthening the axial dimension of the valve body so that the valve element 42 does not come into contact with the fluid valve.

[0117] [Two-piece removal process] Next, we will explain the two-part removal process, which is the process of removing the working valve 4 from the branching portion 2a of the housing 2. The two-part removal process consists of a first process of removing the valve cover 43 containing the valve body 42 from the valve box 41 together, and a second process of removing the valve box 41 from the branching portion 2a.

[0118] In this explanation, it is assumed that the working radius can be made smaller than when the operating valve 4 is assembled by changing the position of the crane, and that the crane has sufficient lifting capacity (weight limit) to suspend the valve cover 43 together with the valve body 42. Also, explanations that overlap with the three-piece removal process described above will be simplified.

[0119] First, the first step of the two-piece removal process will be described. As shown in Figure 45, a lifting tool C, a wire W, and a chain block B are attached to the valve cover 43 with the valve disc 42 housed inside, and the mating flanges at the side ends of the valve box 41 and the valve cover 43 are released using the bolts and nuts 44. The valve cover 43, now released from the valve box 41, is suspended horizontally by the wire W and the chain block B, just as it was before the release. Then, the valve cover 43 is moved horizontally away from the valve box 41 using a crane, the valve disc 42 is released from inside the valve box 41, and the valve cover 43 is removed together with the valve disc 42 (the first step of the two-piece removal process is completed).

[0120] Next, the second step of the two-piece removal process will be described. As shown in Figure 46, a suspender C and a wire W are attached to the valve box 41, and the valve box 41 is removed after the bolts and nuts fastening it to the flange 2b of the branch portion 2a are released (the second step of the two-piece removal process is completed). Thereafter, as shown in Figure 38, a reinforcing element 16 is fixed to the flange 2b with bolts and nuts (not shown).

[0121] In this way, in the two-part removal process, the working valve 4 is separated into a first divided body consisting of the valve disc 42 and valve cover 43, and a second divided body consisting of the valve box 41, and these are removed in order from the branching part 2a of the housing 2, making it possible to remove the working valve 4. This distributes and reduces the weight load on the crane compared to when the working valve 4 is removed from the branching part 2a in an assembled state (working valve 4 with a total weight of 10,500 kg), allowing the crane to be made smaller and the working space required to remove the working valve 4 to be saved.

[0122] Furthermore, in the first step of the two-piece removal process, the valve cover 43 is moved horizontally to remove the valve body 42 from inside the valve box 41, which simplifies the process of removing the valve body 42 compared to a configuration in which the valve body 42 is removed from inside the valve box 41 using chain blocks B1, B2, wires W2 to W5, valve body temporary support 41b, front eyebolt 42a, rear eyebolt 42b, eyebolt 42j, etc.

[0123] Furthermore, in the first step of the two-piece removal process, the feed nut 42f of the valve body 42, which serves as a removal prevention means, is screwed into the feed screw 43a of the valve cover 43, preventing it from coming off the valve cover 43, so that the first step of the working valve removal process can be carried out simply and safely.

[0124] Furthermore, in the first step of the two-part removal process, the valve cover 43 is removed with the valve body 42 still housed inside, so there is no need to advance the valve body 42 into the valve box 41, thereby preventing the valve body 42 from coming into contact with the opening / closing shaft 12 of the butterfly valve 10.

[0125] Furthermore, when assembling the operating valve 4, the first divided body consisting of the valve cover 43, the second divided body consisting of the valve body 42, and the third divided body consisting of the valve box 41 are transported separately, and when removing the operating valve 4, the first divided body consisting of the valve body 42 and the valve cover 43, and the second divided body consisting of the valve box 41 are transported separately. In other words, since there are fewer divided bodies when removing the operating valve 4 than when assembling the operating valve 4, the labor required for removal can be reduced.

[0126] In addition, when assembling the operating valve 4, the operating valve 4 can be assembled with higher precision compared to a configuration in which a valve cover with a valve disc inserted is attached to a valve body, as in Patent Document 1. Therefore, this is particularly suitable when high sealing performance is required.

[0127] Furthermore, when the working valve 4 is removed, the branch portion 2a of the housing 2 is watertight by the butterfly valve 10. Therefore, fewer divisions are required when removing the working valve 4 than when assembling it, which is less likely to cause problems and improves work efficiency.

[0128] [Other two-part removal process] Next, we will explain another two-division removal process, which is a process for removing the working valve 4 and the short pipe 45 from the branching portion 2a of the housing 2. The other two-division removal process consists of a first process of removing the valve cover 43 from the valve box 41 in which the valve disc 42 is housed, a second process of removing the valve box 41 in which the valve disc 42 is housed together from the short pipe 45, and a third process of removing the short pipe 45 from the branching portion 2a. Note that explanations that overlap with the two-division removal process described above will be simplified.

[0129] First, the first step of the other two-piece removal process will be described. As shown in Figure 47, the feed screw 43a is rotated with an electric screwdriver 43b to advance the valve disc 42 until the rear end of the valve disc 42 is positioned inside the valve box 41. Then, a lifting tool C, a wire W, and a chain block B are attached to the valve cover 43, and the mating flanges at the side ends of the valve box 41 and the valve cover 43 are released from the bolts and nuts 44. The valve cover 43, now released from the valve box 41, is suspended horizontally by the wire W and chain block B, just as it was before the release.

[0130] Next, the valve cover 43 is pulled away from the valve box 41 by operating the crane, while the feed screw 43a is rotated with the electric driver 43b to maintain the position of the valve disc 42. Then, the valve disc retaining plate 41d is attached to the opening 41a of the valve box 41 with a bolt through the gap (for example, about 100 mm) between the mating flanges of the side end of the valve box 41 and the side end of the valve cover 43.

[0131] Furthermore, the electric screwdriver 43b is used to rotate the feed screw 43a, disengaging the tip of the feed screw 43a from the feed nut 42f inside the valve body 42, and the valve cover 43 is removed (the first step of the other two-part removal process is completed).

[0132] Next, the second step of the other two-piece removal process will be described. As shown in Figure 48, a suspender C and a wire W are attached to the valve box 41 in which the valve disc 42 is housed, and the valve box 41, which has been released from the fastening to the short pipe 45 with the bolts and nuts, is removed together with the valve disc 42 (end of the second step of the other two-piece removal process).

[0133] Next, the third step of the other two-piece removal process will be described. Referring to Figure 44, a hoisting tool C and a wire W are attached to short pipe 45, and short pipe 45, which has been released from the fastening of flange 2b of branch portion 2a with bolts and nuts, is removed by a crane (completion of the third step of the other two-piece removal process). Thereafter, as shown in Figure 38, reinforcing tool 16 is fixed to flange 2b with bolts and nuts (not shown).

[0134] In this way, in the other two-part removal process, the work valve 4 is separated into a first divided body consisting of the valve cover 43 and a second divided body consisting of the valve body 42 and valve box 41, and these are removed in order from the branching part 2a of the housing 2, making it possible to remove the work valve 4. This distributes and reduces the weight load on the crane compared to when the work valve 4 is removed from the branching part 2a in an assembled state (work valve 4 with a total weight of 10,500 kg), allowing the crane to be made smaller and the work space required to remove the work valve 4 to be saved.

[0135] Furthermore, in the second step of the other two-piece removal process, the valve disc 42 housed in the valve box 41 is prevented from falling out by the valve disc prevention plate 41d serving as a prevention means, which simplifies the work of removing the valve disc 42 compared to a configuration in which the valve disc 42 is removed from the valve box 41 using chain hoists B1, B2, wires W2 to W5, the valve disc temporary holder 41b, the front eyebolt 42a, the rear eyebolt 42b, the eyebolt 42j, etc. Note that the third step of the other two-piece removal process described above may be omitted, and in the preceding second step, the short pipe 45 connected to the valve box 41 may be removed together with the valve box 41 and the valve disc 42 by a crane.

[0136] Although the embodiments of the present invention have been described above with reference to the drawings, the specific configuration is not limited to these embodiments, and the present invention also includes modifications and additions that do not deviate from the gist of the present invention.

[0137] For example, in the above embodiment, in the method of installing the working valve 4, a feed screw 43a and an electric driver 43b are provided as operating parts on the valve cover 43, and the tip of the feed screw 43a is screwed into the feed nut 42f inside the valve box 41 to connect the valve body 42 and the feed screw 43a, but the present invention is not limited to this, and it may also be a form in which an operating part is provided on the valve box 41 and the valve body 42 and the feed screw are connected.

[0138] For example, in the above embodiment, a configuration in which a butterfly valve 10 is used as a fluid control valve is exemplified, but the present invention is not limited to this, and the fluid control valve may be, for example, a gate valve, a plug, a switching valve, etc. For example, in the above embodiment, a configuration in which the butterfly valve 10 is composed of a plurality of divided bodies is exemplified, but the present invention is not limited to this, and the fluid control valve may be composed as a single unit. [Explanation of symbols]

[0139] 1 Fluid tube 2. Case 2a Branching part (opening) 2b Flange (locking part) 4. Working valve 5 cutting machine 6 Valve introducer 7. Jack 8 Drive mechanism 10. Butterfly valve 11 Partition wall 12 Opening and closing axis 13 Valve body 14 Top lid 15 Suppression measures 20 Case 41 Valve box 41a opening 41b Valve body temporary support (mounting portion) 41c Wheel chock 41d Valve body retaining plate (restriction means) 41e Slide groove 42 Valve body 42a Front eyebolt (hanging support) 42b Rear eyebolt (hanging support) 42f Feed nut 42g storage area 42h Nut retaining plate 43 Operculum 43a Lead screw (valve stem, operating part) 43b Electric screwdriver (operating part) 51 Mounting flange cylinder 52 cutter 53 Lid 61 Cylindrical member 62 Locking member 63 Mounting flange cylinder 65 Lid 81,81' Shaft member 86 Case part

Claims

1. A method for installing a working valve for performing a predetermined operation in an enclosure that is hermetically attached to a fluid pipe in an uninterrupted flow state, comprising: The working valve comprises a valve body attached to the opening of the housing, a valve cover attached to the valve body, a valve stem attached to the valve cover and having an operating end at the tip protruding outside the valve cover, and a valve element detachably attached to the valve stem and adapted to move back and forth within the valve body and the valve cover by rotation of the valve stem, a first step of attaching the valve stem provided on the valve cover to the valve body in the valve box installed in the opening of the housing; a second step of attaching the valve cover to the valve body.

2. 2. The method for installing an operating valve according to claim 1, wherein in the first step, the suspended valve cover is moved in a substantially horizontal direction to install the valve stem on the valve body.

3. 2. The method for installing an operating valve according to claim 1, wherein in the first step, the valve cover is hung down vertically from above and the valve stem is attached to the valve body.

4. 4. The method for installing an operating valve according to claim 1, wherein in the second step, the operating end of the valve stem is rotated and the valve cover is attached to the valve body.

5. A method for removing a working valve for performing a predetermined operation in an enclosure that is hermetically attached to a fluid pipe without interrupting flow, comprising: The working valve comprises a valve body attached to the opening of the housing, a valve cover attached to the valve body, a valve stem attached to the valve cover and having an operating end at the tip protruding outside the valve cover, and a valve element detachably attached to the valve stem and adapted to move back and forth within the valve body and the valve cover by rotation of the valve stem, a first step of removing the valve cover from the valve body accommodating the valve body; a second step of removing the valve stem provided on the valve cover from the valve body in the valve body; a third step of removing the valve body and the valve body from the housing; A method for removing a working valve, comprising:

6. 6. The method for removing an operating valve according to claim 5, wherein in the first step, the suspended valve cover is moved in a substantially horizontal direction to remove the valve cover from the valve body.

7. 7. The method for removing an operating valve according to claim 5, wherein in the second step, the operation end of the valve stem is rotated and the valve stem is removed from the valve body.

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