Method for removing the excision device

Abstract

To provide a removal method of a cutting device which enables the cutting device to be removed with a cut piece by using a crane with a low lifting capacity.SOLUTION: A cutting device includes: a cutter 52 having a center drill 52b and a cylindrical member 52a for engaging with a cut piece 1a to hold it; a lid body installed at an opening 2b of a housing 2; a drive mechanism for driving the cutter 52; and holding means 9 provided at the housing 2 below the lid body. A removal method of the cutting device comprises: a closing step in which the cut piece 1a and the cutter 52 are moved to the opening 2b side of the housing 2 relative to a work valve 4 which may open or close the housing 2, and then the work valve 4 is closed; a holding step in which the cutter 52 and the cut piece 1a are held by the holding means 9; a drive mechanism removal step in which the drive mechanism disconnected from the cutter 52 is removed by using a crane; a lid body removal step in which the lid body disconnected from the housing 2 is removed by using the crane leaving the cutter 52 and the cut piece 1a held by the holding means 9; and a cutter removal step in which the cutter 52 is removed from the cut piece 1 and the housing 2 by using the crane.SELECTED DRAWING: Figure 11

Description

Technical Field

[0001] The present invention relates to a removal method for removing, in a non-stop flow state, a cutting device that cuts a part of a fluid pipe from a housing attached to the fluid pipe.

Background Art

[0002] For fluid pipes that form existing pipelines through which water, gas, etc. flow, in order to address aging deterioration or form new branch paths, a part of the existing fluid pipe may be changed to a new fluid pipe, or an aging pipeline may be blocked. In such cases, a part of the fluid pipe may be cut using a cutting device.

[0003] As a method for cutting a fluid pipe in this way, a method for cutting a fluid pipe in a non-stop flow state is known. In such a method, a housing that is attached in a sealed manner to the pipe wall of an existing fluid pipe, a working valve that can open and close the inside of the housing, and a cutting device that is attached in a sealed manner to the opening of the housing are used. This cutting device is mainly composed of a cutter for cutting the fluid pipe, a lid body that can seal and close the opening of the housing, and a drive mechanism for advancing, retreating, and rotating the cutter.

[0004] When cutting a fluid pipe using a cutting device composed of these members, with the cutter disposed inside the housing, the opening of the housing is closed with the lid body, the cutter that rotates by the drive mechanism is advanced toward the fluid pipe to cut the fluid pipe, and after retreating the cutter above the working valve together with the cut piece by the drive mechanism, the inside of the housing is closed with the working valve, so that a non-stop flow state can be maintained throughout a series of steps.

[0005] Such a cutting device is generally suspended by a crane and attached to the installation position inside the housing. Especially when the diameter of the fluid pipe is large, the structure of the cutting device also becomes large and the weight increases, so in order to transport the cutting device in an integrally assembled state, it is necessary to prepare a large crane with a high lifting capacity. Therefore, a large space is required for the arrangement and operation of the crane.

[0006] Therefore, in the installation of the cutting device shown in Patent Document 1, for example, a crane is used to suspend a lid for closing the top of the housing together with the cutter, and after the lid is attached to the housing in a sealed manner, the same crane is used to suspend the drive mechanism in a separate process, and the cutting device is assembled by connecting the drive mechanism, the cutter and the lid. This makes it possible to reduce the lifting capacity required of the crane. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2019-74123 (pages 6, 7, Figure 5) [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] In installing the cutting device described in Patent Document 1, it is possible to attach the cutting device to the housing using a crane with a low lifting capacity, thus enabling the installation of the work valve even in work environments where a large space cannot be secured.

[0009] On the other hand, when removing the cutting device from its housing after cutting the fluid pipe, the process is the reverse of the installation process, that is, the drive mechanism and the cover holding the cutter are separated and removed from the housing. However, the cutter after cutting is heavy because it holds the fluid pipe section, and the weight of the section increases especially as the diameter of the fluid pipe increases or the size of the cut portion of the fluid pipe increases, so there was a risk that it would exceed the lifting capacity of the crane used when installing the cutting device. Therefore, it was necessary to prepare a crane with a higher lifting capacity in anticipation of the weight of the section.

[0010] This invention addresses these problems and aims to provide a method for removing a cutting device that can be removed together with the section using a crane with a low lifting capacity. [Means for solving the problem]

[0011] To solve the above problems, the removal method of the excision device of the present invention is as follows: A removal method comprising cutting the fluid pipe inside a housing attached to the fluid pipe, and then removing the cutting device from the fluid pipe together with the cut piece using a crane while maintaining a continuous flow, The cutting device comprises at least a cutter for holding the section, a lid installed in the opening of the housing, and a drive mechanism for driving the cutter. After moving the cutter together with the aforementioned section toward the opening of the housing beyond the working valve that can open and close the inside of the housing, a closing step is performed to close the working valve. A drive mechanism removal step involves removing the drive mechanism, which has been disconnected from the cutter using the aforementioned crane. A lid removal step involves removing the lid, which has been disconnected from the housing using the crane, The present invention is characterized by comprising a cutter removal step of removing the cutter together with the cut piece from the housing using the crane. This feature allows for the removal of the lid, which has been disconnected from the housing, prior to the removal of the cutter. This reduces the load on the crane when removing the cutter along with the cut pieces. As a result, the cutting device can be removed along with the cut pieces using a crane with a lower lifting capacity, which was used during installation.

[0012] The cutting device further comprises a holding means for holding the cutter which has been moved to the opening side of the housing relative to the work valve, The present invention is characterized by performing a holding step between the closing step and the cover removal step, in which the cutter is held by the holding means. This feature allows the cutter to be held in place by the retaining device, thus enabling the cover to be removed.

[0013] The holding means includes a holder that is provided to be movably in the radial direction relative to the housing, In the holding step, the holder is advanced inward of the housing to hold the cutter. According to this feature, an operation for holding the cutter can be performed from the outside.

[0014] The lid body includes moving means for moving the drive mechanism together with the cutter in a direction away from the fluid pipe. In the holding step, after moving the cutter together with the drive mechanism in a direction away from the fluid pipe by the moving means, the holder is advanced inward of the housing. According to this feature, the work of holding the cutter by the holder can be easily performed.

[0015] In the cutter removal step, a suspended means for connecting the crane to the cutter is provided. According to this feature, the crane can be easily connected to the cutter.

[0016] In the cutter removal step, the crane is connected to a plurality of the suspended means provided at equally spaced positions in the circumferential direction of the cutter. According to this feature, it is easy to achieve weight balance when suspending the cutter by the crane.

Brief Description of the Drawings

[0017] [Figure 1] It is a side sectional view showing a state where a housing is attached to a fluid pipe in an embodiment. [Figure 2] It is a side sectional view showing a state where a cutter is inserted into a housing in the step of attaching a cutting machine. [Figure 3] It is a side sectional view showing a state where a drive mechanism is connected to a cutter in the step of attaching a cutting machine. [Figure 4] It is a side sectional view showing a state where a drive mechanism is connected to a cutter in the step of attaching a cutting machine. [Figure 5]It is a side sectional view showing a state where a fluid pipe is cut by a cutting machine. [Figure 6] It is a side sectional view showing a state where the housing is closed by a working valve in the process of removing the cutting machine. [Figure 7] It is a side sectional view showing a state where the cutter is held in the process of removing the cutting machine. [Figure 8] It is a side sectional view showing a state where the drive mechanism is removed from the cutter in the process of removing the cutting machine. [Figure 9] It is a side sectional view showing a state where the lid is removed from the housing in the process of removing the cutting machine. [Figure 10] It is a plan view for explaining the connection between the cutter and the crane. [Figure 11] It is a side sectional view showing a state where the cutter is withdrawn from the housing together with the cut piece in the process of removing the cutting machine. [Figure 12] It is a plan view for explaining the connection between the cutter and the crane in another aspect.

Mode for Carrying Out the Invention

[0018] A mode for carrying out a method for removing an excision device according to the present invention will be described below based on an example.

Example

[0019] In the example, a series of flows from cutting a predetermined portion of an existing fluid pipe 1 constituting a flow path component by a cutting machine 5 as an excision device to removing the cutting machine 5 in a non-stop flow state will be described with reference to FIGS. 1 to 12.

[0020] As shown in Figure 1, the area around a predetermined location of the fluid pipe 1 buried underground is excavated, and a two-part housing 2 having a branch section 2a opening upwards is sealed around it. The fluid inside the fluid pipe 1 may be, for example, tap water, industrial water, sewage, gas, or a gas-liquid mixture. Furthermore, although the housing 2 is a two-part structure in this embodiment, it may be a multi-part structure, and the two-part housings may be joined by welding or by bolts with gaskets.

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

[0022] Furthermore, when attaching the housing 2 to the fluid pipe 1, a concrete foundation (not shown) is formed below the housing 2 to support the weight around the housing 2 and prevent bending of the fluid pipe 1. Note that the concrete foundation is not the only option; jacks or other supports capable of supporting the weight of the housing 2 and the cutting machine 5 may also be used.

[0023] Furthermore, a packing (not shown) is pressed against the wall of the fluid tube 1 and the housing 2 in the circumferential direction, thereby ensuring a tight seal between the fluid tube 1 and the housing 2. The packing may be press-fitted into a groove provided on the housing 2 side, or into a groove provided on the fluid tube 1 side.

[0024] Furthermore, the housing 2 is equipped with a work valve 4 capable of closing the opening of the branch section 2a. The work valve 4 mainly consists of a substantially cylindrical valve casing 41 sealed above the branch section 2a, a valve element 42 that can seat on the valve seat 41a of the valve casing 41, a valve cover 43 sealed to the valve casing 41 and capable of housing the valve element 42, and a valve stem 44 that connects the valve element 42 to the valve cover 43 so as to be able to move back and forth. By rotating the valve stem 44 in the forward and reverse directions, the work valve 4 can close the inside of the housing 2 by advancing the valve element 42 toward the valve casing 41 and seating it on the valve seat of the valve casing 41, or it can open the inside of the housing 2 by retracting the valve element 42 toward the valve cover 43.

[0025] Furthermore, the housing 2 includes a substantially cylindrical mounting flange cylinder 21 that is sealed and connected to the upper part of the valve body 41. An opening 2b that opens upward is formed at the upper end of the mounting flange cylinder 21.

[0026] Next, the process of attaching the cutting machine 5 for cutting the fluid pipe 1 above the mounting flange cylinder 21 will be described. As shown in Figure 2, first, the cutter 52 and the cover 53 are temporarily installed on the mounting flange cylinder 21. Specifically, the cutter 52 and the cover 53 of the mounting flange cylinder 21 connected above it are suspended together by a lifting device C equipped with a hook and wire W suspended from a crane (not shown) and lowered above the mounting flange cylinder 21.

[0027] In this embodiment, a mobile rough terrain crane is preferable, and it goes without saying that its size will increase according to its lifting capacity. Also, the installation area of ​​the crane, including outriggers, is often larger than the excavation area of ​​the fluid pipe 1. The selection of the rough terrain crane to be used is based on whether it has the lifting capacity to lift the heaviest component among the components, the allowable lifting load at the slewing radius, and so on.

[0028] The cutter 52 consists of a cylindrical member 52a with cutting blades at its circumferential end, and a center drill 52b that is coaxially positioned on the cylindrical member 52a and protrudes further forward than the drilling blade. The cylindrical member 52a and the center drill 52b are fixed together. An adapter 54, with an annular projection 54a formed at its upper end, is mounted above the cylindrical member 52a and the center drill 52b so as to be unable to rotate relative to it.

[0029] The lid 53 has a through hole 53a that penetrates vertically through its center, and the adapter 54 is inserted through the through hole 53a. The lid 53 also has multiple recesses 53b formed circumferentially, recessed radially outward from the inner surface of the through hole 53a, and a fixing jig 55 that can move back and forth radially in the direction of the through hole 53a is disposed in the recesses 53b. The fixing jig 55 protrudes inward in the direction of the through hole 53a and engages with the lower surface of the annular projection 54a of the adapter 54, thereby releasably connecting the cutter 52 and the lid 53. In addition, multiple jacks 7 (moving means) that can extend and retract vertically are fixed to the upper surface of the lid 53 on the outer diameter side of the through hole 53a.

[0030] Next, as shown in Figure 3, the cover 53 is placed on top of the mounting flange cylinder 21, and the mounting flange cylinder 21 and the cover 53 are aligned and fixed with bolts and nuts (not shown). As a result, the opening 2b of the mounting flange cylinder 21 that constitutes the housing 2 is sealed, and the cutter 52 is housed inside the mounting flange cylinder 21.

[0031] Furthermore, a packing (not shown) is pressed against the opening 2b of the mounting flange cylinder 21 and the cover 53 in the circumferential direction, thereby ensuring a tight seal between the mounting flange cylinder 21 and the cover 53. The packing may be press-fitted into a groove provided on the cover 53 side, or into a groove provided on the mounting flange cylinder 21 side.

[0032] Next, the drive mechanism 8 of the cutting machine 5 is connected to the cutter 52. First, the structure of the drive mechanism 8 will be explained.

[0033] As shown in Figure 3, the drive mechanism 8 mainly consists of a shaft member 81, a gripping member 82 capable of gripping or releasing the shaft member 81, a reciprocating member 83 that moves the gripping member 82 back and forth within the axial range of the shaft member 81, a restricting member 84 that can restrict or release the movement of the shaft member 81 at a position below the reciprocating member 83, and a base member 85 to which the reciprocating member 83 and the restricting member 84 are attached.

[0034] The base member 85 is provided with multiple support columns that are erected on top of it, and the reciprocating member 83 is mounted so as to be able to slide vertically along the support columns. In other words, the shaft member 81 is gripped by the gripping member 82, and in that state, the reciprocating member 83 is moved along the support columns, thereby allowing the shaft member 81 to slide vertically.

[0035] Furthermore, a cylindrical case portion 86 through which the shaft member 81 can be inserted is provided below the base member 85. An extended piece 86a extending in a substantially horizontal direction is formed at the lower end edge of the case portion 86.

[0036] Furthermore, a rotary motor 87 is fixed to a part of the reciprocating member 83, and by applying rotational force to the gripping member 82, which is gripping the shaft member 81, rotation can be transmitted to the shaft member 81, and the rotation of the shaft member 81 can cause the cutter 52 to rotate. In addition, by providing multiple shaft members 81, the axial length can be increased by joining them together in the axial direction, and this joining structure can reduce weight and height.

[0037] When connecting the drive mechanism 8 configured in this way to the cutter 52, refer to Figure 4, advance the shaft member 81 downward by a predetermined length in advance so that the lower end of the shaft member 81 protrudes below the case portion 86, suspend the drive mechanism 8 with the lifting device C and wire W, and fix the extended piece 86a of the case portion 86 to the upper end of the rod that extends upward from the base of the jack 7.

[0038] Next, an operator accesses the gap between the case portion 86 and the upper flange 53c of the lid 53 and connects the shaft member 81 and the adapter 54 with bolts and nuts. Then, the fixing jig 55 is retracted into the recess 53b. The extended piece 86a is not necessarily required here; for example, a support mechanism may be placed between the upper flange 53c and the drive mechanism 8. Alternatively, it may be placed on the ground instead of the upper flange 53c.

[0039] Next, as shown in Figure 4, the rod is housed in the base of the jack 7, the case portion 86 is placed on the upper flange 53c of the lid 53, and the case portion 86 and the lid 53 are secured with bolts and nuts (not shown). As a result, the cutting machine 5 is composed of the cutter 52, the lid 53, the adapter 54, and the drive mechanism 8, and the load on the crane during a single lift can be reduced compared to transporting the cutting machine 5 as a single unit. This allows the cutting machine 5 to be installed in the housing 2 using a small crane with a low lifting capacity. Needless to say, the center drill 52b is adjusted so that it does not come into contact with the valve body 42 when closed (see Figure 6).

[0040] In this embodiment, the drive mechanism 8 is lowered using the jack 7 as an example. However, to enhance safety, the drive mechanism 8 may be lowered using the jack 7 while being loosely suspended by the lifting device C and wire W. This reduces the load on the crane and alleviates the strain on the crane. Alternatively, the drive mechanism 8 may be lowered using the crane without using the jack 7.

[0041] Furthermore, when the case portion 86 and the lid 53 are fixed together, the packing (not shown) is pressed against the case portion 86 and the upper flange 53c of the lid 53, thereby ensuring a tight seal between the case portion 86 and the lid 53. The packing may be press-fitted into an annular groove formed on the lower surface of the case portion 86, or into an annular groove provided on the upper flange 53c side of the lid 53.

[0042] Next, as shown in Figure 5, with the valve body 42 of the work valve 4 retracted into the valve cover 43 to open the branch section 2a, the drive mechanism 8 is operated to advance the cutter 52 and cut the fluid pipe 1 in a continuous flow state. At this time, by connecting another shaft member 81' to the shaft member 81, the distance the cutter 52 moves can be adjusted as appropriate.

[0043] Furthermore, a recess 2e is formed at the bottom of the housing 2 so as to be recessed downwards. When the fluid pipe 1 is cut by the cutter 52, the center drill 52b, which protrudes below the lower end of the cylindrical member 52a, is housed in the recess 2e at a distance from it, thereby preventing the center drill 52b from unintentionally damaging the housing 2.

[0044] Furthermore, a valve (not shown) is installed at the bottom of the recess 2e. By opening this valve, the chips generated when the cutter 52 cuts the fluid pipe 1 can be discharged to the outside along with the fluid through the drain.

[0045] Here, as shown in Figure 6, the tip of the center drill 52b is provided with a holder 52g that is expandable in the outer diameter direction of the center drill 52b and is used to lock and hold the section 1a of the fluid pipe 1, which will be described later. While the center drill 52b is drilling through the wall of the fluid pipe 1, the holder 52g is housed on the inner diameter side of the outer circumferential surface of the center drill 52b, as shown by the dotted line in the blowhole in Figure 6. Once the pipe wall has been penetrated, the holder 52g expands on the outer diameter side of the outer circumferential surface of the center drill 52b, as shown by the solid line in the blowhole in Figure 6. As a result, the section 1a of the fluid pipe 1 cut by the cutter 52 is locked to the holder 52g and held inside the cylindrical member 52a.

[0046] Next, the method for removing the cutting machine 5 will be described. The removal of the cutting machine 5 is carried out in the following order: closure process, holding process, drive mechanism removal process, cover removal process, and cutter removal process.

[0047] First, as shown in Figure 6, a closure process is performed. In this process, the drive mechanism 8 is operated to pull the cutter 52 upward together with the section 1a, causing the valve body 42 of the work valve 4 to retract into the mounting flange cylinder 21 above the position where it can move. Then, the valve stem 44 is rotated in the forward direction to advance the valve body 42 into the valve casing 41, thereby closing the inside of the housing 2.

[0048] Next, as shown in Figure 7, a holding process is performed. In this process, first, the bolts and nuts fixing the case portion 86 of the drive mechanism 8 and the upper flange 53c of the cover 53 are removed, the jack 7 is extended, and the drive mechanism 8 and cutter 52 are moved upward together.

[0049] Here, the peripheral wall of the mounting flange cylinder 21 has multiple recesses 21a formed in the circumferential direction, recessed from its inner circumferential surface in the outer diameter direction. As shown in the blown-out section of Figure 7, a retainer 90 that can move back and forth in the radial direction of the mounting flange cylinder 21 is disposed in the recesses 21a. The retainer 90 is prevented from rotating by the inner circumferential surface of the recesses 21a. In addition, a spindle 91 is rotatably supported at the outer diameter end of the recess 21a. A male thread is formed on this spindle 91, which is screwed into the female threaded hole of the retainer 90.

[0050] As a result, by rotating the operating part of the spindle 91, which is open to the outside of the mounting flange cylinder 21, in forward and reverse directions, the retainer 90 advances toward the inner diameter side of the mounting flange cylinder 21, or the retainer 90 retracts into the recess 21a. In other words, the mounting flange cylinder 21, the retainer 90, and the spindle 91, which are part of the housing 2, constitute the retaining means 9 of the present invention.

[0051] Furthermore, the cutter 52 has an annular flange 52c formed on the upper end of the cylindrical member 52a, protruding outwards. The flange 52c may also be formed on the upper end portion 52d of the cutter 52 (see Figure 10), which will be described later. Its location and shape may be changed as appropriate, as long as it can hold the cutter 52. For example, it may be a projection that matches the position of the holder 90 rather than an annular shape.

[0052] Returning to the explanation of the holding process, the spindle 91 is rotated forward from the outside of the mounting flange cylinder 21, causing the holder 90 to advance toward the inner diameter side of the mounting flange cylinder 21 and engage with the lower surface of the flange 52c of the cutter 52, thereby holding the cutter 52 in place of the housing 2. At this time, as described above, the cutter 52 is moved by the jack 7, so the cutter 52 can be easily held by the holder 90. In addition, the flange 52c of the cutter 52 allows the holder 90 to easily engage with the cutter 52.

[0053] Next, as shown in Figures 7 and 8, the drive mechanism removal process is performed. In this process, the bolts and nuts connecting the shaft member 81 and the adapter 54 are removed, and these connections are released. Even after releasing these connections, the load of the cutter 52 and the section 1a is still held to the housing 2 by the holder 90. Subsequently, the fixing between the rod of the jack 7 and the extended piece 86a of the case portion 86 is also released. Then, although not shown directly in the illustration, the drive mechanism 8 is lifted and removed using the lifting device C and wire W (see Figure 8).

[0054] Next, as shown in Figures 8 and 9, the cover removal process is carried out. In this process, the bolts and nuts fixing the mounting flange cylinder 21 and the cover 53 are removed, and the cover 53 is lifted and removed using the lifting device C and wire W (see Figure 9).

[0055] Next, as shown in Figures 10 and 11, the cutter removal process is performed. In this process, as shown in Figure 10, the shackles S are first attached to the four female screw holes 52e that are evenly spaced in the circumferential direction on the upper end portion 52d of the cutter 52. At this time, the cutter 52 is held near the opening 2b, which is the upper end of the housing 2, making it easy to attach the shackles S.

[0056] Then, the wire W is connected to the shackle S, and the cutter 52 is lifted together with the cut piece 1a by the lifting device C and the wire W, and removed (see Figure 11). At this time, since the female screw holes 52e are evenly spaced in the circumferential direction of the cutter 52, it is easy to balance the weight when lifting the cutter 52. This allows the cutter 52 and the cut piece 1a to be safely removed without tilting. In this way, the female screw holes 52e and the shackle S constitute the lifting means of this embodiment. Note that the female screw holes 52e are not limited to being evenly spaced in four places; they may be evenly spaced in two or more places, or not even spaced evenly, and the number and arrangement may be changed as appropriate. Also, the mounting position of the shackle S may be appropriately selected from among multiple (for example, 10) female screw holes 52e.

[0057] Furthermore, as shown in Figure 12, the upper end portion 52d of the cutter 52 has six communication holes 52f arranged to allow fluid to escape when cutting the fluid pipe 1. Therefore, a lifting device C can be attached to a lifting belt B that is inserted through a pair of adjacent communication holes 52f, 52f, and the cutter 52 can be lifted together with the cut piece 1a using the lifting device C and belt B for removal. In other words, the upper end portion 52d of the cutter 52 having communication holes 52f is also a means of being lifted.

[0058] Although not shown directly in the diagram, the load acting on the shackle S, wire W, and belt B may be distributed by using them in combination.

[0059] In this way, the fluid pipe 1 can be cut while maintaining a continuous flow state, the cutting machine 5 can be removed from the housing 2, and the cut piece 1a can be recovered.

[0060] As described above, in the method for removing the cutting machine 5 of this embodiment, by removing the cover 53, which has been disconnected from the housing 2, prior to removing the cutter 52, the load on the crane when removing the cutter 52 together with the cut piece 1a can be reduced. As a result, the cutting machine 5 together with the cut piece 1a can be removed using a small crane with a low lifting capacity that was used during installation.

[0061] Although embodiments of the present invention have been described above with reference to the drawings, the specific configurations are not limited to these embodiments, and any changes or additions that do not depart from the spirit of the present invention are also included.

[0062] For example, in the above embodiment, a cutting machine 5 having a cutter 52 which is a hole saw was described as an example of a cutting device, but it is not limited to this, and the cutting device may be a drilling machine, as long as it cuts off at least a part of the peripheral wall of the fluid pipe 1.

[0063] Furthermore, although it has been explained that the holding means 9 is composed of a mounting flange cylinder 21, a holder 90, and a spindle 91, it is not limited to this, and the holding means may be provided with the holder 90 and spindle 91 on, for example, the valve body 41 of the work valve 4 or a lid having a cylindrical part, or the cutter 52 may be placed on the valve body 42 of the work valve 4, and may be modified as appropriate.

[0064] Furthermore, although the retainer 90 has been described as moving radially in accordance with the rotation of the spindle 91, it is not limited to this configuration. For example, it may be a bolt screwed into the peripheral wall of the mounting flange cylinder 21, or it may be configured to move radially by a jack, and may be modified as appropriate.

[0065] Furthermore, although the jack 7 has been described as being fixed to the lid 53, the configuration is not limited to this, and it may be provided in a detachable manner. [Explanation of Symbols]

[0066] 1 Fluid tube 1a intercept 2 cabinets 2b opening 4. Working valve 5 Cutting machine (cutting device) 7. Jack (means of movement) 8 Drive mechanism 9 Retention means 52 cutters 52d Upper end (suspended means) 52e Female screw hole (suspended means) 53 Lid 90 Holder 91 spindles S Shackle (means of suspension)

Claims

1. A removal method comprising cutting the fluid pipe inside a housing attached to the fluid pipe, and then removing the cutting device from the fluid pipe together with the cut piece using a crane while maintaining a continuous flow, The cutting device comprises at least a cutter having a center drill and a cylindrical member for locking and holding the section, a cover installed in the opening of the housing, a drive mechanism for driving the cutter, and a holding means provided in the housing below the cover. After moving the cutter together with the aforementioned section toward the opening of the housing beyond the working valve that can open and close the inside of the housing, a closing step is performed to close the working valve. A holding step in which the cutter and the section are held by the holding means, A drive mechanism removal step involves removing the drive mechanism, which has been disconnected from the cutter using the aforementioned crane. A lid removal step in which the lid is removed by using the crane from which the drive mechanism has been removed, leaving the cutter and the cut piece held by the holding means in place, and disconnecting the lid from the housing, A method for removing a cutting device, comprising: a cutter removal step, in which a plurality of lifting means are provided at equally spaced circumferential locations in the cutter, the lifting means are connected to the crane from which the drive mechanism and the cover have been removed, and the cutter is removed from the housing together with the cut piece.

2. The method for removing a cutting device according to claim 1, characterized in that the suspension means includes a female screw hole formed in the cutter and a shackle attached to the female screw hole.

3. The method for removing the cutting device according to claim 1, characterized in that the suspension means includes a communication hole formed at the upper end of the cutter for releasing fluid.

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