Attachment method and removal method of 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 mounting an operating valve for performing a predetermined operation within a housing that seals a fluid pipe under an uninterrupted flow condition. [Background technology]

[0002] In order to deal with deterioration of existing fluid pipes that constitute existing pipelines through which water, gas, etc. flow, or to form new branch paths, a part of the existing fluid pipe 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 work including the step of opening the opening, a method is known in which the work is performed in an uninterrupted flow state using an operating valve. The operating valve is mainly composed of a valve box attached to the opening of the housing which is fixed in a hermetically sealed manner to the fluid pipe, a valve cover attached to the valve box, and a valve body capable of reciprocating within the valve box and the valve cover. When the opening of the fluid pipe is open, the valve body can be moved to a closing position where it closes the inside of the valve box to prevent the fluid from leaking out of the housing, while the valve body can be moved to an open position where it retreats into the valve cover to make the opening accessible.

[0004] The operating valve is generally transported to the installation position by a crane and attached to the housing. In particular, when the diameter of the fluid pipe is large, the structure of the operating valve is also large and heavy, so that a large crane with high lifting capacity is required to transport the operating valve in an assembled state, and a large space is required for the placement and handling of the crane.

[0005] Therefore, for example, there is a method of attaching an operating valve to a housing by dividing the operating valve into a valve body and a valve cover with a valve body inserted therein, attaching the valve body to the opening of the housing, and then attaching the valve cover with the valve body inserted therein to the valve body, as shown in the method of attaching an operating valve to a housing 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] In the method of installing the working valve of Patent Document 1, the divided working valve can be assembled and installed in the housing using a crane with low lifting capacity, so that the working valve can be installed even in a work environment where a large space cannot be secured. However, the valve cover with the valve body inserted must be moved horizontally while aligning the height position with the valve box installed earlier, and the tip of the valve body that protrudes slightly outward from the valve cover must be inserted into the valve box, so that it is difficult to visually check the tip of the valve body. In addition, since the valve body itself is not suspended by a crane, but the valve cover with the valve body inserted is directly suspended, the valve body in the valve cover may be unstable and may swing during work, making it difficult to insert the tip of the valve body into the valve box with high accuracy and install it. In addition, if the tip of the valve body comes into contact with the opening of the valve box, the valve body may be damaged, which may affect the sealing performance of the working valve itself.

[0008] The present invention has been made in view of such problems, and has an object to provide a method of 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 problems, the method for installing an operating valve of the present invention includes the steps of: A method for mounting an operating valve for performing a predetermined operation in an uninterrupted flow state within a housing that is hermetically mounted to a fluid pipe, comprising the steps of: The working valve includes a valve box attached to the opening of the housing, a valve cover attached to the valve box, and a valve body provided to be movable forward and backward within the valve box 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 forward and backward; and a fourth step of attaching the valve cover to the valve body. According to this feature, the valve box, valve disc, and valve cover of the working valve are each separated, and the valve disc is first inserted into the valve box installed in the housing, and then the valve cover is attached to the valve box, so that the valve disc is inserted into the valve box separately from the valve cover, and the valve disc can be grasped as a whole and the attitude of the valve disc can be controlled, so that the valve disc can be inserted into the opening of the valve box with high precision, and the risk of the valve disc coming into contact with the opening of the valve box can be reduced, so that the valve disc is not damaged and the sealing of the working valve itself can be maintained. Furthermore, since the working valve is separated into the valve box, valve disc, and valve cover and lifted and transported separately by a crane, the weight of each item lifted by the crane is small, and a small crane can be used, so that the work can be carried out even in a situation where there is not enough working space, and since each item is small in weight, handling can be improved, and the difficulty of attaching the working valve to the housing can be reduced.

[0010] In the third step, the retraction of the valve element inserted into the valve box is restricted by a restricting means. According to this feature, the valve disc 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 disc back and forth.

[0011] In the second step, the valve body is suspended by a plurality of suspension parts in the direction of travel, and after the front side of the valve body is inserted into the valve box, the suspension parts 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 that the valve body can be inserted further into the valve box while maintaining an approximately parallel state similar to the state 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 operating portion connected to the valve body is operated to bring the valve cover closer to the valve body. According to this feature, by operating the operating part connected to the valve body with respect to the valve body inserted into the valve box, the valve cover can be brought closer to the valve box, and by working together 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 the valve disc is inserted into the valve box, it can be placed on the mounting portion that protrudes into the opening of the valve box and aligned, so that the valve disc can be inserted smoothly without colliding with the valve box.

[0015] The operating unit includes a valve rod that is provided on the valve cover and moves the valve body forward and backward. In the third step, a tip end of the valve stem is attached to a rear end of the valve body 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 an operating portion 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, the locking portion being vertically connected, The valve stem is characterized in that a locked portion of the valve rod is locked to the locking 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 installation easy. [Brief description of the drawings]

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

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for mounting an operating valve according to the present invention will be described below with reference to the accompanying drawings. EXAMPLES

[0019] In the embodiment, a series of steps from cutting a specified portion of an existing fluid pipe 1 constituting a flow path component and installing a butterfly valve 10 (fluid control) at the cut portion, to a series of steps for removing the working valve 4 after the butterfly valve 10 (fluid control) is installed, will be described with reference to Figures 1 to 48.

[0020] As shown in Fig. 1, a predetermined portion of a fluid pipe 1 buried in the ground is excavated, and a two-part housing 2 having a branch portion 2a opening upward is enclosed in a sealed manner. The fluid in the fluid pipe 1 may be, for example, clean water, industrial water, sewage, or a gas or a gas-liquid mixture of gas and liquid. 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 and is formed in 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, etc. Furthermore, the inner circumferential surface of the fluid pipe may be covered with an epoxy resin layer, mortar, plating, etc., or the inner circumferential surface of the fluid pipe may be covered 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 working valve 4 capable of closing the opening of the branching part 2a to the branching part 2a (opening) of the housing 2 will be described in order. Here, the working valve 4 of this embodiment is mainly composed of a valve box 41, a valve body 42, and a valve cover 43 as described later, and is a valve that can open and close the branching part 2a of the housing 2. First, the first step of the attachment process of installing the valve box 41 to the branching part 2a (opening) of the housing 2 will be described. As shown in FIG. 1, the valve box 41 constituting the working valve 4 is suspended from above by a hoisting tool C equipped with a hook suspended by a crane (not shown) and a wire W, and placed on the flange 2b of the branching part 2a, and the flange 2b and the valve box 41 are fixed with bolts and nuts (not shown) while adjusting the position of the valve box 41 on the flange 2b (first step of the attachment process is completed). Next, a plurality of valve body temporary supports 41b as mounting parts are attached to the lower side of the opening 41a of the valve box 41 at intervals in the width direction. The valve body temporary support 41b (mounting portion) has a vertical surface and a horizontal surface, and is generally in the shape of a right-angled triangle when viewed from the front. The vertical surface abuts against the lower end surface of the opening 41a of the valve box 41, and the horizontal surface is extended 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 generally flush with the surface of the slide groove 41e. The valve body temporary support 41b may be attached to the valve box 41 after the valve box 41 is fixed to the branch part 2a of the housing 2 as in this embodiment, or the valve box 41 may be fixed to the branch part 2a of the housing 2 with the valve body temporary support 41b attached to the valve box 41 in advance. The crane used in this embodiment is preferably, for example, a mobile rough terrain crane, and it goes without saying that the crane is made larger according to its lifting capacity, and the specifications capable of lifting the heaviest member among the members described later are selected while considering the allowable lifting load at the turning radius. Furthermore, the installation area of ​​the crane, including outriggers, etc., 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 valve box 41 is connected to the crane with the wire W slightly loosened to ensure safety, but this is not limited to the above, and the hoisting tool C and the wire W may be removed from the valve box 41. Also, in order to make it easier to adjust the position of the valve box 41, the position of the valve box 41 may be adjusted relative to the flange 2b while being slightly suspended by the crane.

[0025] The valve box 41 is generally cylindrical and penetrates in the vertical direction, and a slide groove 41e is formed extending generally horizontally from an opening 41a provided on one side. The slide groove 41e guides the movement of a front wheel 42c and a rear wheel 42d provided on the lower part of the valve body 42, which will be described later. The weight of the valve box 41 in this embodiment is approximately 4500 kg. An O-ring (not shown) is pressed between the flange 2b and the valve box 41, so that the branch part 2a and the valve box 41 are connected in a sealed state. The weights of the various components described below are merely examples, and can be changed as appropriate.

[0026] Next, the second step of the installation process for inserting the valve body 42 into the valve box 41 will be described. As shown in Fig. 2, a front eyebolt 42a is attached as a suspending support to two places on the front side (left side in the figure) in the insertion direction, and a rear eyebolt 42b is attached as a suspending support to two places on the rear side (right side in the figure) in the insertion direction at the four corners of the upper part of the valve body 42 constituting the working valve 4. A front wheel 42c and a rear wheel 42d are attached to the lower part of the valve body 42, and a plurality of side wheels 42i are attached to the sides. The front wheel 42c and the rear wheel 42d are guided along a slide groove 41e provided in the valve box 41, and the plurality of side wheels 42i are guided by contacting with the inner surface of the valve box 41, so that the valve body 42 can be smoothly inserted and moved into the valve box 41. Furthermore, the front wire W1 and the rear wire W2 are passed through the front eye bolt 42a and the rear eye bolt 42b, respectively, and the valve body 42 is lifted by the lifting tool C so that it is horizontal with the front wire W1 and the rear wire W2, and is lowered to the side of the opening 41a of the valve box 41, and the front wheel 42c of the valve body 42 is mounted on the valve body temporary support 41b attached to the side of the opening 41a of the valve box 41. Here, the length of the front wire W1 is made extendable by attaching a chain block B to the front wire W1 in advance. In FIG. 2, the length of the front wire W1 and the length of the rear wire W2 are approximately the same, so that the valve body 42 can be stably suspended horizontally. Then, the front wheel 42c of the valve body 42 is first placed on the valve body temporary support 41b, and then the wheel stopper 41c for the front wheel 42c of the valve body 42 is inserted into the valve body temporary support 41b to prevent the valve body 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 Fig. 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 body 42 is always kept horizontal. Once the rear wire W2 becomes vertical and the front wire W1 is confirmed to be loose, the front wire W1 and the front eye bolt 42a are removed from the valve body 42. At this time, the load on the front side of the valve body 42 is supported by the valve body temporary support base 41b, and the load on the rear side of the valve body 42 is suspended by the rear wire W2, so that the valve body 42 does not move horizontally when the front eye bolt 42a is removed, and a stable state can be maintained.

[0029] Next, as shown in Fig. 4(a), a retraction eyebolt 42e is provided on the upper part of the rear end of the valve disc 42, and the valve box 41 and the valve disc 42 are connected by a wire W3 and a chain block B' for retracting the valve disc. Then, in cooperation with the state of being suspended by the wire W2, the length of the wire W3 is adjusted so as to be 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 located at a position of about 200 mm from the valve box mating flange surface, a valve disc retaining plate 41d as a restricting means for restricting the retreat 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', the wires W2, W3, the rear eyebolt 42b, and the retraction eyebolt 42e are removed. 4(b), the valve disc stopper plate 41d (control 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 eye bolt 42a (suspension support) on the front side of the valve body 42 in the direction of travel 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 that the valve body 42 can be inserted further into the valve box 41 while maintaining an approximately parallel state similar to the state when it is suspended by a crane.

[0031] Next, the third attachment step of connecting the valve element 42 with the valve stem as an operating part for moving the valve element back and forth will be described. As shown in Fig. 5, the valve lid 43 is lifted up horizontally using a wire W and a chain block B. A long feed screw 43a (valve stem) is built in the valve lid 43 and extends horizontally inside the valve lid 43. The feed screw 43a is supported rotatably within the valve lid 43 and cannot move forward or backward in the axial direction. The tip of the feed screw 43a protrudes forward beyond the valve lid 43 and can be screwed into a feed nut 42f provided at the rear end of the valve element 42 inserted into the valve box 41. The valve body 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 body 42, and the feed screw 43a in the valve lid 43 is rotated at a slow speed using an electric screwdriver 43b attached to the rear end of the valve lid 43, and the tip of the feed screw 43a is screwed into the feed nut 42f in the valve body 42, thereby connecting the valve body 42 and the feed screw 43a (the third step of the attachment process is completed). Note that the feed screw 43a is not necessarily turned using the electric screwdriver 43b, and it may be turned manually using a handle or the like (not shown).

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

[0033] In this way, the feed nut 42f is gradually screwed from the tip of the feed screw 43a toward the base end side (the right side in the figure), so that 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 back and forth by the valve body removal prevention plate 41d (regulating means) that was previously attached.

[0035] 6 and 7 show a modified example in which the valve body 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 rod) is built into the valve cover 43, and a feed nut 42f' as a locked part is screwed onto the tip of the feed screw 43a in advance. On the other hand, as shown in FIG. 7, the valve body 42 has a substantially rectangular shape with a protruding rear end in a plan view, and a storage section 42g as a locking part is provided at the rear end of the valve body 42, which is open at the top so that the feed nut 42f' can be accommodated therein without being rotated from above. In addition, a pair of nut retaining plates 42h are provided at the rear of the storage section 42g, separated from each other so that the top is open so that the feed nut 42f' does not come off, and the distance between the pair of nut retaining plates 42h is slightly larger than the diameter of the feed screw 43a and has a width smaller than the width of the feed nut 42f'. As shown in Fig. 7, by inserting the feed screw 43a with the feed nut 42f' screwed to its tip into the storage section 42g of the valve body 42, the front, rear and side faces 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, and the feed nut 42f' is stored in an unrotatable manner, and the feed screw 43a continuing to the feed nut 42f' is sandwiched between the nut retaining plates 42h, and movement is restricted 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' screwed to the tip of the feed screw 43a is fitted into the storage section 42g from above, and the valve body 42 and the feed screw 43a are connected (the third step of the installation process in the modified example is completed). Using an electric screwdriver 43b, the feed screw 43a in 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) screwed onto the feed screw 43a (valve stem) can be moved vertically and engaged with the storage portion 42g (engaging portion) of the valve body 42, thereby making it possible to attach the feed screw 43a (valve stem) to the valve body 42, thus making installation easy.

[0037] Next, a fourth step of the installation process for installing the valve cover 43 on the valve box 41 will be described. As shown in Fig. 8, the feed screw 43a is then rotated slowly using the electric screwdriver 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 of the side end of the valve box 41 and the side end of the valve cover 43 becomes small (for example, about 100 mm), the valve body retaining plate 41d is removed.

[0038] Next, as shown in FIG. 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 (completion 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 step of the installation process with the entire valve body 42 inserted into the opening 41a of the valve box 41, the valve body 42 is not exposed, so that it is easy to align the valve cover 43 to the valve box 41, and it is possible to prevent the rear end of the valve body 42 from contacting the valve cover 43, and to avoid damage to the rear end of the valve body 42. After the joining and fixing are confirmed, the wire W and chain block B that held the valve cover 43 are removed. Finally, the feed screw 43a in the valve cover 43 is rotated using the electric screwdriver 43b to completely pull the valve body 42 in the valve box 41 toward the valve cover 43, that is, the valve body 42 is retreated to the "open" position.

[0041] In this way, the working valve 4 is mainly composed of the first divided body composed of the valve box 41, the second divided body composed of the valve body 42, and the third divided body composed of the valve cover 43, and the working valve 4 is configured by assembling these in order to the branching part 2a of the housing 2. In other words, since the first divided body, the second divided body, and the third divided body can be transported separately by 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 good weight balance, and compared to the case where the working valve 4 is installed in the branching part 2a in an assembled state (working valve 4 with a total weight of 10,500 kg), the load on the crane can be distributed and reduced, so that the crane can be made smaller and the work space for installing the working valve 4 can be saved. In addition, since the load on the hoisting tool C and the wire W is also reduced, there is no need to prepare thick hoisting tool C and wire W, and the cost of the hoisting tool C and wire W used can be reduced.

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

[0043] Moreover, the working valve 4 is composed of a valve box 41 installed above the branching section 2a, and a valve body 42 and a valve cover 43 that bulge out laterally from the valve box 41. After the valve box 41 is fixed to the branching section 2a, the valve body 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 branching section 2a, the load does not tilt due to weight balance, and installation of the valve box 41 in the branching section 2a is simplified. Similarly, when connecting the valve cover 43 to the valve box 41, the load does not tilt due to weight balance, and connection of the valve cover 43 to the valve box 41 is simplified.

[0044] In addition, 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 moved while being guided 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 body 42, and valve cover 43 of the operating valve 4 are each separated, and first the valve body 42 is 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 body 42 is inserted into the valve box 41 separately from the valve cover 43, the entire valve body 42 can be grasped and the posture of the valve body 42 can be controlled, so that the valve body 42 can be inserted into the opening 41a of the valve box 41 with high accuracy, and the risk of the valve body 42 coming into contact with the opening 41a of the valve box 41 can be reduced, so that the valve body 42 is not damaged and the sealing ability of the operating valve 4 itself can be maintained. Furthermore, since the operating valve 4 is divided into the valve box 41, valve body 42, and valve cover 43 and is lifted and transported individually 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 insufficient work space.In addition, since the weight of each component is small, handling is improved and the difficulty of attaching the operating valve 4 to the housing 2 can be reduced.

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

[0048] Next, as shown in Fig. 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 upper part 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 is composed of a cylindrical member 52a equipped with a cutting blade at its peripheral end and a center drill 52b arranged coaxially with the cylindrical member 52a and projecting forward beyond the boring blade, and the cylindrical member 52a and the center drill 52b are fixed. In addition, an adapter 54 having 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, and the adaptor 54 is inserted into the through hole 53a. The cover 53 has a plurality of recesses 53b formed in the circumferential direction, the recesses 53b being recessed in the outer diameter direction from the inner peripheral surface of the through hole 53a, and a fixing jig 55 capable of moving forward and backward in the radial direction of the through hole 53a is disposed in the recesses 53b. The fixing jig 55 protrudes in the inner diameter direction of the through hole 53a and engages with the lower surface of the annular protrusion 54a of the adaptor 54, thereby integrating the cutter 52 and the cover 53.

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

[0051] 12, the mounting flange tube 51 and the lid body 53 are aligned with each other with the lid body 53 placed on the mounting flange tube 51, and then fixed with bolts and nuts (not shown). At this time, the cutter 52 is housed inside the mounting flange tube 51.

[0052] 12, the packing S2 is pressed between the mounting flange tube 51 and the lid body 53 in the circumferential direction, thereby ensuring a tight seal between the mounting flange tube 51 and the lid body 53. Note that, although the embodiment has been described in terms of an example in which the packing S2 is pressed into a groove provided on the lid body 53 side, the present invention is not limited to this, and a groove may be provided on the mounting flange tube 51 side, and the packing S2 may be pressed into the 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 forward and backward 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 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 preparing multiple shaft members 81, it is possible to extend the axial length by adding more members, 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 a predetermined length in advance until the lower end of the shaft member 81 protrudes downward beyond the case part 86. The drive mechanism 8 is 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 the 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 86 and the cover 53, and the fixture 55 is retracted into the recess 53b. At this time, the cutter 52 (approximately 2910 kg), adapter 54 (approximately 290 kg), and drive mechanism 8 (approximately 6060 kg) are lifted by the crane, so the weight on the crane is approximately 9260 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 the weight, thereby reducing the weight on the crane.

[0058] 16, the drive mechanism 8 is lowered by a crane so that the case portion 86 is placed on the upper flange 53c of the cover 53, and the case portion 86 and the cover 53 are fixed with bolts and nuts (not shown). As a result, the mounting flange tube 51, cutter 52, cover 53, adapter 54 and drive mechanism 8 constitute the cutting machine 5, and the housing 2, working 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, a process of cutting the fluid pipe 1 by the cutting machine 5 will be described. As shown in Fig. 17, first, the valve body 42 of the working valve 4 is retracted to open the branch portion 2a, and the outer circumferential 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 inside of the mounting flange tube 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, a process of installing a valve introducer 6 for installing a butterfly valve 10 at a location where the fluid pipe 1 is cut will be described. As shown in FIG. 19, first, while the branch portion 2a is closed by the valve body 42 of the working valve 4, a cylindrical member 61 (cylindrical body) penetrating in the vertical direction is suspended by a suspender C and a wire W and lowered to above the working valve 4, and the cylindrical member 61 is fixed above the working valve 4 by bolts and nuts (not shown). The weight of the cylindrical member 61 in this embodiment is approximately 3000 kg. In addition, an O-ring (not shown) is pressed between the cylindrical member 61 and the working valve 4 (valve box 41), so that the cylindrical member 61 and the working valve 4 are connected in a hermetically sealed manner.

[0062] Next, there will be described a process for 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 state in which the fluid can pass and a state in which the fluid cannot pass, and includes a partition wall 11 having an opening at approximately the center, an opening / closing shaft 12 rotatably attached to the upper end of the partition wall 11, a valve body 13 that can open and close the opening of the partition wall 11 by rotating around the opening / closing shaft 12, and a substantially circular upper cover portion 14 (cover portion) that extends in a substantially horizontal direction and is connected in a sealed manner to the upper end of the partition wall 11. A packing S5 is fixed to both side surfaces and the bottom surface of the partition wall 11, and a packing S6 is fixed to the upper cover portion 14 around the entire outer periphery of the outer periphery, and the packings S5 and S6 are connected so as to be continuous. The total weight of the butterfly valve 10 in this embodiment is approximately 9540 kg. Needless to say, the gap between the partition wall 11 and the upper cover portion 14 is sealed with a packing or the like.

[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 body 13 (main body) are suspended in an integrated state by a suspender C and a wire W and lowered to a position where they will be housed in the cylindrical member 61. At this time, the valve body 13 is positioned so as to be approximately parallel to the pipe axis direction (a state in which the opening of the partition wall 11 is open).

[0065] Then, a locking member 62 (locking portion, holding portion) is inserted from the outside through a plurality of windows 61a formed in the circumferential direction of the cylindrical member 61 so as to partially protrude 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 a portion of the valve body 13 is formed in the lower portion on 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 the upper part of the partition wall 11 with the opening / closing shaft 12 inserted therethrough. The upper cover 14 and the partition wall 11 are then connected in a hermetic manner by a fixing means (not shown) to form the butterfly valve 10.

[0067] 22, the mounting flange tube 63 penetrating in the vertical direction 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 above the cylindrical member 61 by 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 bottom surface of the mounting flange tube 63, and an annular packing S7 is press-fitted into the annular groove 63a. When the cylindrical member 61 and the mounting flange tube 63 are fixed, the packing S7 is pressed between the cylindrical member 61 and the mounting flange tube 63, so that sealing between the cylindrical member 61 and the mounting flange tube 63 can be ensured. Note that, in this embodiment, the packing S7 is press-fitted into the annular groove 63a formed on the bottom surface of the mounting flange tube 63, but this is not limiting, and an annular groove may be provided on the cylindrical member 61 side, and the packing S7 may be press-fitted into the annular groove.

[0069] Next, as shown in Fig. 23, a valve hanging fitting 64 connected to the butterfly valve 10 is temporarily installed on the mounting flange tube 63. More specifically, with the cover 65 of the mounting flange tube 63 connected to the upper part of the valve hanging fitting 64, it is suspended by a hanging tool C and a wire W and lowered to the upper part of the mounting flange tube 63. The valve hanging fitting 64 has a mounting surface portion 64a facing substantially horizontally, a cylindrical shaft portion 64c extending upward from a through hole 64b provided at the substantially center of the mounting surface portion 64a, and a reinforcing rib 64d provided between the mounting surface portion 64a and the shaft portion 64c. An adapter 66 is connected to the upper end of the shaft portion 64c.

[0070] The lid 65 has a through hole 65a formed in the center penetrating in the up-down direction, and an adaptor 66 is inserted into the through hole 65a. The lid 65 has a plurality of recesses 65b formed in the circumferential direction, recessed from the inner peripheral surface of the through hole 65a in the outer diameter direction, and a fixing jig 67 that can advance and retreat in the radial direction of the through hole 65a is disposed in the recesses 65b. The fixing jig 67 protrudes in the inner diameter direction of the through hole 65a and engages with the underside of the annular protrusion 66a of the adaptor 66, thereby integrating the valve hanging fitting 64 and the lid 65.

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

[0072] 24, the packing S8 is pressed between the mounting flange tube 63 and the lid body 65 in the circumferential direction, thereby ensuring a tight seal between the mounting flange tube 63 and the lid body 65. Note that, in this embodiment, the form in which the packing S8 is pressed into the groove provided on the lid body 65 side has been exemplified, but this is not limiting, and a groove may be provided on the mounting flange tube 63 side, and the packing S8 may be pressed into the groove.

[0073] Next, the drive mechanism 8 serving as the insertion mechanism of the valve introducer 6 is connected to the valve hanging fixture 64. Note that the drive mechanism 8 is the same as that used during the cutting operation of the fluid pipe 1, and therefore 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 length so that the lower end of the shaft member 81 protrudes downward beyond the case portion 86, and multiple jacks 7 (spacers) are placed in the circumferential direction of the upper flange 65c of the cover body 65, the drive mechanism 8 is suspended by a crane, and the case portion 86 is placed on the jacks 7. Next, an operator accesses through a gap formed by the jacks 7 between the case portion 86 and the upper flange 65c of the cover body 65, and connects the shaft member 81 and the adapter 66 with bolts and nuts N2.

[0075] 26, the drive mechanism 8, the adapter 66, and the valve hoisting fitting 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 fitting 64 (approximately 2000 kg), the adapter 66 (approximately 270 kg), and the drive mechanism 8 (approximately 6060 kg) are lifted by the hoisting tool C and the wire W, so that the weight applied to the hoisting tool C and the wire W is approximately 8330 kg. At this time, a plurality of jacks 7 (spacers) may be arranged in the circumferential direction of the lower flange 65d of the cover 65, and the drive mechanism 8 may be placed on the jacks 7 to support the weight, thereby reducing the weight applied to the crane.

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

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

[0078] Next, a process of installing the butterfly valve 10 at the portion of the fluid pipe 1 cut by the valve introducer 6 will be described. As shown in Fig. 28, the valve body 42 of the working valve 4 is retracted to open the branch portion 2a, and the outer circumferential surface of the rear end side of the shaft member 81 is gripped by the gripping member 82 described above. Then, the advancing and 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 forward movement of the shaft member 81 and the butterfly valve 10 occurs in 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 the movement of the shaft member 81 and the butterfly valve 10 after the forward movement is completed 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 place the butterfly valve 10 at the cut portion of the fluid pipe 1. After the butterfly valve 10 is 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 holding means 15. At this time, it is not necessarily required to connect another shaft member 81', and the placement may be completed using a shaft member 81 of a predetermined length in advance.

[0080] Regarding the restraining means 15 in detail, the restraining means 15 is mainly composed of a through-hole that penetrates the peripheral wall of the housing 2 and has a female thread, and a bolt-shaped member that is inserted into the through-hole and screwed into the female thread, and the through-holes and the bolt-shaped members are arranged at equal intervals in the circumferential direction. As a result, the bolt-shaped member is advanced to the inner diameter side of the housing 2 by rotating in a predetermined direction, and is arranged above the corner of the upper cover part 14 of the butterfly valve 10. As a result, the tip of the bolt-shaped member abuts against the upper surface of the corner of the upper cover part 14, thereby preventing the butterfly valve 10 from coming off. Note that the restraining means may be separate from the advancement means that is screwed into the female thread of the through-hole and the abutment means that abuts against the fluid valve, and the number and arrangement of the abutment means 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 top 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 around between the partition wall 11 and the housing 2 and preventing the fluid from leaking from the branch portion 2a.

[0082] 29, the fluid within the cylindrical member 61 and the mounting flange tube 63 is discharged to the outside, and the mounting surface 64a of the valve hanging fitting 64 and the top cover 14 of the butterfly valve 10 are released with the bolt and nut by accessing 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 hanging fitting 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 portion 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 Fig. 30, a cutting machine 500 in a modified example is composed of a cutter mechanism 501 fitted onto a predetermined portion 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 be raised into the work case 502.

[0084] The cutter mechanism 501 includes two sprockets 501a, 501a rotatably provided in the outer circumferential direction of the fluid pipe 1, and a drive transmission unit 501b that transmits a drive force to the sprockets 501a, 501a, and a cutting tool (not shown) that cuts the fluid pipe 1 is attached to the sprockets 501a, 501a. The drive mechanism 800 also includes a rod 801 connected to the drive transmission unit 501b, a motor 802 that drives and rotates the rod 801, and a lifting mechanism 803 that can lift up the rod 801.

[0085] By driving the motor 802, the sprockets 501a, 501a rotate via the rod 801 and the drive transmission unit 501b, and the fluid pipe 1 can be cut. 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 holding the cut piece of the fluid pipe 1.

[0086] Next, the process of 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 branching 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 branching portion 2a (see Figures 32 onwards).

[0087] When removing the valve introduction device 6, the work is performed in a procedure that is almost the reverse of that when the valve introduction device 6 is constructed. Briefly, from the state shown in Fig. 29, the drive mechanism 8, the adapter 66, and the valve hanging fitting 64 are lifted slightly upward by the lifting tool C and the wire W, and the case part 86 is placed on a plurality of jacks 7 arranged in the circumferential direction of the upper flange 65c of the cover body 65 (see Fig. 25). Next, the fixing tool 67 is engaged with the adapter 66 (see Fig. 23), and the drive mechanism 8, which has been released from the fastening with the adapter 66 by the bolt nut N2 through the gap between the case part 86 and the upper flange 65c, is lifted and removed by the lifting tool C and the wire W (see Fig. 24). Furthermore, the fastening between the mounting flange tube 63 and the cover body 65 by the bolt nut or the like is released, and the valve hanging fitting 64, the cover body 65, and the adapter 66 are lifted and removed by the lifting tool C and the 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 by 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 by the lifting tool C and wire W (see Figure 19).

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

[0089] First, the first step of the three-part removal step will be described. As shown in FIG. 32, the feed screw 43a is rotated by the electric screwdriver 43b to advance the valve body 42 into the valve box 41, and the front end of the valve body 42 is connected to the valve box 41 by the wire W4 and the chain block B1, which are the restricting means in the insertion direction, through the opening on the upper side of the valve box 41. At this time, the length of the wire W4 is adjusted by the chain block B1 so that the valve body 42 can be restricted from contacting the opening / closing shaft 12 of the butterfly valve 10 located in the valve box 41. This makes it possible to prevent damage caused by the valve body 42 contacting the opening / closing shaft 12 and leakage from the branch part 2a of the housing 2. Note that the restricting means in the insertion direction is not limited to the wire W4 and the chain block B1, and may be, for example, a rod-like or string-like member that is adjusted to a predetermined length and has a locking part that can be locked to the housing 2 or the valve body 42, or may be changed as appropriate.

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

[0091] Next, the valve cover 43 is pulled in a direction away from the valve box 41 by operating the crane, while the feed screw 43a is rotated by the electric screwdriver 43b to hold the position of the valve body 42. Then, when the rear end of the valve body 42 is exposed outside the valve cover 43, an eyebolt 42j is provided at the rear end, and the valve box 41 and the valve body 42 are connected by the wire W5 and the chain block B2, which are restricting means in the removal direction. Then, at a position where a part of the valve body 42 is stored in the valve box 41 and the rest is exposed to the outside of the valve box 41, the length of the wire W5 is adjusted by the chain block B2 so that the valve body 42 can be restricted from tilting or from unintentionally coming out of the valve box 41. This makes it possible to work easily and safely. The restricting means in the removal direction is not limited to the wire W5 and the chain block B2, and may be, for example, a rod-like or string-like member that is adjusted to a predetermined length and has an engaging portion that can be engaged with the housing 2 or the valve body 42, and may be changed as appropriate.

[0092] Furthermore, while the valve cover 43 is pulled in a direction away from the valve box 41 by operating the crane, the feed screw 43a is rotated using the electric screwdriver 43b to detach the tip of the feed screw 43a 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 Fig. 33, a plurality of valve body temporary holders 41b are attached to the opening 41a of the valve box 41, and wheel stops 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 eye bolts 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 element 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 element 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, so that the valve element 42 is smoothly removed from the valve box 41 and travels.

[0096] As shown in FIG. 35, the valve body 42 is moved substantially horizontally in the removal direction to a position where the front eye bolt 42a can be attached. At this time, the front wheel 42c of the valve body 42 is moved outside the valve box 41 and onto the multiple valve body temporary support stands 41b, so that the valve body 42 is held at the same height as when it is inserted into the valve box 41. This prevents a sudden load from acting on the crane. Furthermore, by moving the valve body 42 until the movement is restricted by the wheel stopper 41c, not only is it prevented from coming out, but the valve body 42 can also be positioned at a position where the front eye bolt 42a can be attached. In other words, it is possible to easily align the valve body 42 to a position where the front eye bolt 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, 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 the rear wire W2. In Fig. 35, the length of the front wire W1 and the length of the rear wire W2 are approximately the same, so that the valve body 42 can be stably suspended horizontally.

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

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

[0100] 38, an annular reinforcing member 16 is fixed to the flange 2b with bolts and nuts (not shown). The reinforcing member 16 has an annular protrusion extending in the axial direction that abuts against the upper cover portion 14 of the butterfly valve 10 while fixed to the flange 2b, reinforcing the butterfly valve 10 against coming off.

[0101] Thus, in the three-division removal process, the working valve 4 is divided into a first divided body composed of the valve cover 43, a second divided body composed of the valve body 42, and a third divided body composed of the valve box 41, and these are removed in order from the branching part 2a of the housing 2, thereby making it possible to remove the working valve 4. This makes it possible to distribute and reduce the weight load on the crane compared to removing the working valve 4 in an assembled state from the branching part 2a (working valve 4 with a total weight of 10,500 kg) or removing the working valve 4 made of multiple members by dividing it into a number less than the number of members (for example, removing it by dividing it into two divided bodies in the case of three members), so that the crane can be made smaller and the work space required to remove the working valve 4 can be saved.

[0102] Furthermore, when assembling the working 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 working 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. In other words, because the divided bodies when assembling the working valve 4 and the divided bodies when removing the working valve are the same, it is possible to use the same crane and perform work in the same work space when assembling and removing the working 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 body 42 and the feed screw 43a are connected, the connection between the valve body 42 and the valve cover 43 can be released by pulling out the feed nut 42f' screwed onto the tip of the feed screw 43a upward from the storage portion 42g of the valve body 42. The other procedures are the same as those described above.

[0104] [Other 3-part removal process] Next, we will explain another three-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 three-division 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 branching portion 2a and the valve box 41. By disposing the working valve 4 on the short pipe 45, the valve body 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 body 42. Also, explanations that overlap with the above-mentioned three-part removal process will be omitted.

[0106] First, the first step of the other three-part removal process will be described. As shown in Figure 39, the feed screw 43a is rotated by the electric screwdriver 43b to advance the valve body 42 to its rear end into the valve box 41. In other words, the entire valve body 42 is stored in the valve box 41. Then, the hanging tool C, wire W, and chain block B are attached to the valve cover 43, and the fastening of the mating flanges of the side ends of the valve box 41 and the valve cover 43 by the bolts and nuts 44 (see Figure 9) is released. The valve cover 43, which has been released from the valve box 41, is suspended horizontally in the same manner as before the fastening was released.

[0107] Next, while pulling the valve cover 43 in a direction away from the valve box 41, the feed screw 43a is rotated with an electric screwdriver 43b (see FIG. 32) to maintain the position of the valve body 42. Then, the valve body 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.

[0108] Furthermore, the feed screw 43a is rotated using the electric screwdriver 43b to disengage the tip of the feed screw 43a from the feed nut 42f inside the valve body 42, and the valve lid 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 step will be described. First, the valve body 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 valve body 42 can be moved even by manual power using the front wheel 42c and the multiple side wheels 42i of the valve body 42. Furthermore, by moving the valve body 42 until it abuts against the valve body retaining plate 41d, not only is it prevented from coming out, but the valve body 42 can also be positioned at a position where the rear eyebolt 42b can be attached. Note that the position adjustment of the valve body 42 does not have to be made to abut against the valve body retaining plate 41d, and may be changed as appropriate.

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

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

[0112] Next, the third step of the other three-part removal process will be described. As shown in Fig. 43, the valve body temporary support 41b is removed, the hoist C and 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 by the bolts and nuts, is removed by a crane (the third step of the other three-part removal process is completed).

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

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

[0115] Incidentally, the fourth step of the other three-part removal process described above may be omitted, and in the preceding third step, the short pipe 45 connected to the valve box 41 may be removed together with the valve box 41 by using a crane.

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

[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 part 2a of the housing 2. The two-part removal process consists of a first process of removing the valve cover 43 housing the valve body 42 from the valve box 41 together, and a second process of removing the valve box 41 from the branching part 2a.

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

[0119] First, the first step of the two-part removal process will be described. As shown in Fig. 45, a hoist C, a wire W, and a chain block B are attached to the valve cover 43 in which the valve body 42 is housed, and the fastening of the mating flanges of the side end of the valve box 41 and the side end of the valve cover 43 by the bolts and nuts 44 is released. The valve cover 43, which has been released from the valve box 41, is suspended horizontally by the wire W and the chain block B in the same manner as before the fastening was released. Then, the valve cover 43 is moved horizontally away from the valve box 41 by operating the crane, the valve body 42 is released from inside the valve box 41, and the valve cover 43 is removed together with the valve body 42 (the first step of the two-part removal process is completed).

[0120] Next, the second step of the two-part removal process will be described. As shown in Fig. 46, a suspender C and a wire W are attached to the valve box 41, and the valve box 41 is released from the fastening with the flange 2b of the branch part 2a by the bolts and nuts and is removed (the second step of the two-part removal process is completed). After that, as shown in Fig. 38, a reinforcing tool 16 is fixed to the flange 2b by bolts and nuts (not shown).

[0121] Thus, in the two-part removal process, the working valve 4 is divided into a first divided body consisting of the valve body 42 and the 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 makes it possible to distribute and reduce 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), so that the crane can be made smaller and the working space required to remove the working valve 4 can be saved.

[0122] Furthermore, in the first step of the two-piece removal process, the valve cover 43 can be moved horizontally to remove the valve body 42 from within the valve box 41, making the task of removing the valve body 42 simpler than in a configuration in which the valve body 42 is removed from within the valve box 41 using chain blocks B1, B2, wires W2 to W5, the valve body temporary support stand 41b, the front eye bolt 42a, the rear eye bolt 42b, the eye bolt 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 prevention means, is screwed into the feed screw 43a of the valve cover 43, preventing it from coming off from the valve cover 43. This makes it possible to carry out the first step of the working valve removal process simply and safely.

[0124] Furthermore, in the first step of the two-piece removal process, the valve cover 43 is removed with the valve body 42 still housed therein, 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 working 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 working 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 working valve 4 than when assembling the working 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 high accuracy compared to a configuration in which a valve cover with a valve body inserted is attached to a valve body as in Patent Document 1. Therefore, this is suitable for cases where high sealing performance is required.

[0127] Furthermore, when the working valve 4 is removed, the branched portion 2a of the housing 2 is watertight by the butterfly valve 10. Therefore, problems are less likely to occur even if the number of divided bodies is reduced when removing the working valve 4 compared to when it is assembled, which improves work efficiency.

[0128] [The other two-part removal process] Next, a description will be given of 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 is made up of a first process of removing the valve cover 43 from the valve box 41 in which the valve body 42 is housed, a second process of removing the valve box 41 in which the valve body 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 descriptions that overlap with the two-division removal process described above will be omitted.

[0129] First, the first step of the other two-part 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 body 42 until the rear end of the valve body 42 is positioned inside the valve box 41. Then, a hanging tool C, a wire W, and a chain block B are attached to the valve cover 43, and the fastening of the mating flanges of the side end of the valve box 41 and the side end of the valve cover 43 by the bolts and nuts 44 is released. The valve cover 43, which has been released from the valve box 41, is suspended horizontally by the wire W and the chain block B in the same manner as before the fastening was released.

[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 by the electric driver 43b to hold the position of the valve body 42. Then, the valve body 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 feed screw 43a is rotated using the electric screwdriver 43b to disengage 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-part removal process will be described. As shown in Fig. 48, a suspender C and a wire W are attached to the valve box 41 in which the valve body 42 is housed, and the valve box 41, which has been released from fastening to the short pipe 45 with the bolts and nuts, is removed together with the valve body 42 (end of the second step of the other two-part removal process).

[0133] Next, the third step of the other two-part removal process will be described. With reference to Fig. 44, a suspender C and a wire W are attached to the short pipe 45, and the short pipe 45, which has been released from the fastening with the flange 2b of the branch portion 2a by the bolts and nuts, is removed by a crane (end of the third step of the other two-part removal process). After that, as shown in Fig. 38, a reinforcing member 16 is fixed to the flange 2b by bolts and nuts (not shown).

[0134] Thus, in the other two-part removal process, the working valve 4 is divided 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 working valve 4. This makes it possible to distribute and reduce the weight load on the crane compared to the case in which 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), so that the crane can be made smaller and the working space required to remove the working valve 4 can be saved.

[0135] In addition, in the second step of the other two-part removal process, the valve disc 42 housed in the valve box 41 is prevented from falling out by the valve disc prevention plate 41d as a prevention means, so the work of removing the valve disc 42 can be simplified compared to a configuration in which the valve disc 42 is removed from inside the valve box 41 using the chain blocks B1, B2, wires W2-W5, the valve disc temporary support stand 41b, the front eyebolt 42a, the rear eyebolt 42b, the eyebolt 42j, etc. Note that the third step of the other two-part 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 an operating part on the valve cover 43, and the tip of the feed screw 43a is screwed into the feed nut 42f in the valve box 41 to connect the valve body 42 and the feed screw 43a. However, the present invention is not limited to this, and the present invention may also be configured so that 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 the butterfly valve 10 is used as the fluid control valve is exemplified, but the present invention is not limited to this, and for example, the fluid control valve may be 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 an integral unit. [Explanation of symbols]

[0139] 1 Fluid tube 2. Chassis 2a Branching section (opening) 2b Flange (locking part) 4 Working valve 5 cutting machine 6 Valve introduction machine 7 Jack 8 Driving mechanism 10. Butterfly valve 11 Partition Wall 12 Opening and closing axis 13 Valve body 14 Top cover 15 Suppression measures 20. Cabinet 41 Valve box 41a opening 41b Valve body temporary support (mounting part) 41c Wheel chock 41d Valve body retaining plate (control means) 41e Slide groove 42 Valve body 42a Front eyebolt (hanging support) 42b Rear eye bolt (hanging support) 42f Feed Nut 42g Storage area 42h Nut retaining plate 43 Opercula 43a Lead screw (valve stem, operating part) 43b Electric screwdriver (operation part) 51 Mounting flange tube 52 Cutter 53 Lid 61 Cylindrical member 62 Locking member 63 Mounting flange tube 65 Lid 81,81' Shaft member 86 Case part

Claims

1. A method for mounting an operating valve for performing a predetermined operation in an uninterrupted flow state within a housing that is hermetically mounted to a fluid pipe, comprising the steps of: The working valve includes a valve box attached to an opening of the housing, a valve cover attached to the valve box, a valve stem attached to the valve cover and having an operating end at a tip protruding outside the valve cover, and a valve body detachably attached to the valve stem and capable of advancing and retreating within the valve box 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 valve cover is suspended and moved in a substantially horizontal direction to install the valve stem to 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 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 an operating valve for performing a predetermined operation in an uninterrupted flow state within a housing that is hermetically attached to a fluid pipe, comprising the steps of: The working valve includes a valve box attached to an opening of the housing, a valve cover attached to the valve box, a valve stem attached to the valve cover and having an operating end at a tip protruding outside the valve cover, and a valve body detachably attached to the valve stem and capable of advancing and retreating within the valve box and the valve cover by rotation of the valve stem, a first step of removing the valve cover from the valve body housing the valve body; a second step of removing the valve stem provided on the valve cover from the valve body in the valve body.

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 or 6, 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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