JP7572932B2 - Cutting device - Google Patents

Description

The present invention relates to a cutting device.

A cutting device described in Patent Document 1 below is known as a conventional technique in this field. This cutting device arranges a wire saw tool so that it is wrapped around the object to be cut, and cuts the object by urging and pulling the wire saw tool using a rack and pinion mechanism while the wire saw tool is running.

Japanese Patent Application Laid-Open No. 5-256031

In this type of cutting device, wet cutting is generally performed while pouring water into the cutting area to prevent cutting chips from scattering. However, depending on the environment, water cannot be used and dry cutting may be necessary. Therefore, the object of the present invention is to provide a cutting device that prevents cutting chips from scattering when performing dry cutting with a wire saw tool.

The cutting device of the present invention comprises a frame that holds a pair of pulleys, a wire saw tool that runs between the pulleys, a frame drive unit that moves the frame relative to the object to be cut so that the object crosses between the pulleys, and a protective sheet unit that moves over the surface of the object to be cut as the frame moves relative to the object to be cut, covering the cut groove formed in the object to be cut by the wire saw tool.

The protective sheet portion may be made of a flexible member that connects predetermined portions of the frame and hangs down at both ends, and may include a first sheet portion that exists along an imaginary plane that is parallel to the direction of movement of the frame relative to the object to be cut and that follows the trajectory of the wire saw tool, and the first sheet portion may come into contact with the surface of the object to be cut and deform along the surface as the frame moves relative to the object to be cut.

The protective sheet portion may also be made of a flexible member having one end fixed to a predetermined portion of the frame and the other end hooked onto a predetermined suspended guide portion whose position is fixed relative to the object to be cut, and may include a second sheet portion that exists along an imaginary plane that is parallel to the direction of movement of the frame relative to the object to be cut and that follows the trajectory of the wire saw tool, and the second sheet portion may hang down from the suspended guide portion under its own weight so as to cover the vertical surface of the object to be cut as the frame moves relative to the object to be cut.

The cutting device of the present invention can move on rails that are provided along the surface of the workpiece to be cut, and may further include a dust collection duct that moves near the wire saw tool.

The present invention provides a cutting device that suppresses scattering of cutting chips when performing dry cutting with a wire saw tool.

1 is a cross-sectional view showing a main part of a reactor building to which a cutting device according to an embodiment is applied. FIG. 1 is a perspective view showing a cutting device according to a first embodiment. 1A and 1B are perspective views of a piece to be cut. 5A and 5B are diagrams illustrating a process of cutting a piece by a cutting device. 1A is a perspective view showing the cutting device during a cutting process of a section, and FIG. 1B is a front view showing the cutting device at the time when the cutting process of the section is completed. FIG. 11 is a perspective view showing a cutting device according to a second embodiment. FIG. 4 is a front view showing the cutting device at the completion of the cutting process of the section.

First Embodiment
Hereinafter, a first embodiment of the cutting device according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a main part of a reactor building 101 of a BWR (boiling water reactor) nuclear power plant to which the cutting device of the present embodiment is applied. FIG. 2 is a perspective view showing the cutting device 1 according to the present embodiment. As shown in FIG. 1, the reactor building 101 includes a reactor pressure vessel (RPV) 103 having a circular shape in a plan view, a cylindrical thermal shield wall (RSW) 105 surrounding the periphery of the pressure vessel 103, a biological shield (BSW) 107 further surrounding the periphery of the thermal shield wall 105, and a pedestal (RPV) 109 supporting the thermal shield wall 105. Furthermore, an overhead crane 111 is provided on the ceiling of the reactor building 101.

The cutting device 1 is used to dismantle the thermal shielding wall 105 when the reactor building 101 is decommissioned and dismantled. The thermal shielding wall 105 is a vertical cylindrical structure with a diameter of about 7 to 8 m, a height of about 14 m, and a wall thickness of about 0.7 m. The thermal shielding wall 105 is a steel structure made of I-beams and steel plates filled with shielding concrete or mortar, so a dry wire saw method that can cut both concrete and steel materials at the same time is used to cut the thermal shielding wall 105.

When dismantling the heat shielding wall 105, the upper end of the heat shielding wall 105 is cut horizontally in a predetermined manner to separate it into ring-shaped pieces 125 (Fig. 3), and the separated pieces 125 are lifted and moved by a ceiling crane 111 to the operation floor 115 provided on the upper surface of the biological shielding body 107, where they are further processed. By repeating this process, the heat shielding wall 105 is divided into about 10 pieces 125 from top to bottom, and each piece 125 is processed in turn on the operation floor 115, completing the dismantling of the heat shielding wall 105.

On the operation floor 115, each piece 125 is processed using the cutting device 1, for example, as follows. Figures 3(a) and (b) are perspective views of the piece 125. As shown in Figure 3(a), the ring-shaped piece 125 is cut into a rectangular cross section 125a perpendicular to the circumferential direction using the cutting device 1. By repeating this cutting process using the cutting device 1, as shown in Figure 3(b), the piece 125 is divided into about 10 smaller pieces 127 in the circumferential direction, for example, and the smaller pieces 127 are then stored in containers or other processing.

4(a) and (b) are diagrams showing a simplified process of cutting the slice 125 by the cutting device 1. As shown in FIG. 4, the cutting device 1 includes a base 3 and a movable cutting unit 5 that is movable relative to the base 3. The movable cutting unit 5 is attached to the hinge shaft 3a of the base 3 and can rotate in a vertical plane around the hinge shaft 3a. The movable cutting unit 5 has a rectangular shape that exists along a plane perpendicular to the axis of rotation of the hinge shaft 3a, and one vertex of the rectangle is attached to the hinge shaft 3a. The movable cutting unit 5 also includes a U-shaped frame 7 that extends along three sides of the rectangle, a wire saw tool 9 that is hung on the frame 7 along the remaining side of the rectangle, and a wire saw drive unit 11 (FIG. 2) that runs the wire saw tool 9.

The piece 125 is placed within the rotation range of the wire saw tool 9 with the movable cutting part 5 positioned on the outer peripheral surface 125b side of the piece 125, and the movable cutting part 5 is rotated while the wire saw tool 9 is traveling by the wire saw driving part 11, so that the piece 125 is cut from the outer peripheral surface 125b side by the wire saw tool 9 as shown in FIG. 4(b), and the cutting groove 125j expands, and finally the piece 125 is cut with a rectangular cross section 125a (FIG. 3(a)). Note that the power source for rotating the movable cutting part 5 relative to the base part 3 is not particularly limited, but in the cutting device 1 of this embodiment, a hydraulic cylinder 41 (FIG. 3) is used as the power source. Both ends of the hydraulic cylinder 41 are joined to the movable cutting part 5 and the base part 3, respectively, and the hydraulic cylinder 41 expands and contracts to rotate the movable cutting part 5 relative to the base part 3. The hydraulic cylinder 41 functions as a frame drive unit that moves the frame 7 relative to the segment 125 so that the segment 125 crosses between the cutting pulleys 13T, 13T described below.

The configuration of the cutting device 1 will be described in more detail with reference to FIG. 2. In the following, as shown in the figure, the vertical direction is the Z direction, the direction of the axis of rotation of the hinge shaft 3a is the X direction, and the direction perpendicular to both the Z direction and the X direction is the Y direction, and XYZ may be used to explain the positional relationship of each part.

The main body of the movable cutting unit 5 is formed by combining, for example, multiple H-shaped steels and square pipes. The movable cutting unit 5 has multiple pulleys 13 attached to the main body. The pulleys 13 are arranged in the same plane parallel to the YZ plane along the rectangular outer periphery of the movable cutting unit 5, and each rotates around a rotation axis in the X direction. The wire saw tool 9 is hung on each pulley 13 in sequence and extends endlessly on a predetermined orbit that connects each pulley 13 in sequence. The wire saw drive unit 11 described above has a drive pulley 13A, which is one of the multiple pulleys 13, and a motor 15 attached to the drive pulley 13A. The drive pulley 13A is rotated by the motor 15 as a drive source, and the wire saw tool 9 travels on a predetermined orbit while being guided by each pulley 13. The orbit of the wire saw tool 9 exists approximately along the four sides of the rectangular movable cutting unit 5.

The multiple pulleys 13 also include a pair of cutting pulleys 13T, 13T. The cutting pulleys 13T, 13T are provided on both ends of the U-shaped frame 7. A portion of the wire saw tool 9 is hung between the above-mentioned cutting pulleys 13T, 13T, and cuts the cut piece 125 as described above. The portion of the wire saw tool 9 that is hung between the cutting pulleys 13T, 13T and cuts the cut piece 125 in this manner is referred to below as the "cutting portion 9a."

The base 3 is formed by combining, for example, steel plates, H-shaped steel, etc. Wheels may be provided on the base 3 to facilitate the movement of the cutting device 1. The base 3 has a guide rail 19 that rises vertically near the installation position of the cut piece 125. A dust collection duct 21 is attached to the guide rail 19, and the dust collection duct 21 can slide vertically on the guide rail 19. The dust collection duct 21 is located below the cutting part 9a in a vertical plane along the cutting part 9a, and the dust collection port 21a of the dust collection duct 21 faces the vertical surface of the cut piece 125. During cutting of the cut piece 125 by the cutting part 9a, the dust collection duct 21 moves on the guide rail 19 so that the dust collection port 21a is always located at a position intersecting the cutting part 9a. During cutting, cutting chips generated in the cutting section 9a are sucked in through the dust collection port 21a, and then passed through the dust collection duct 21 and the dust delivery duct 21b to be collected by a downstream collection device (not shown).

To enable the dust collection duct 21 to move up and down as described above, a drive motor 23 is provided on the frame 7, and the drive motor 23 is connected to the dust collection duct 21 via a wire 23a and a pulley 23b. When the drive motor 23 winds up the wire 23a, the dust collection duct 21 rises along the guide rail 19, and when the drive motor 23 sends out the wire 23a, the dust collection duct 21 descends along the guide rail 19 under its own weight. During cutting of the cut piece 125 by the cutting unit 9a, the drive motor 23 is separately controlled in accordance with the rotation of the movable cutting unit 5 about the hinge shaft 3a, so that the dust collection duct 21 moves on the guide rail 19 so that the dust collection port 21a is always located at a position that intersects with the cutting unit 9a, as described above.

The cutting device 1 further includes a first protective sheet 27 and a second protective sheet 29, which are flexible and arranged above the cutting section 9a. The first protective sheet 27 and the second protective sheet 29 are, for example, rubber sheets. The cutting section 9a, the first protective sheet 27, and the second protective sheet 29 are present along the same vertical plane. The first protective sheet 27 is arranged to connect predetermined parts of the frame 7 and hang down at both ends. Both ends of the first protective sheet 27 are attached to different parts of the frame 7, and the center part is hooked on the upper end of the guide rail 19 and hangs down. The first protective sheet 27 is a long strip with a predetermined width in the X direction, and the length of the first protective sheet 27 is longer than the sum of the height and width of the rectangular cross section 125a (FIG. 3(a)) of the slice 125.

The second curing sheet 29 is located below the first curing sheet 27 and is installed so as to be hooked onto the upper end of the guide rail 19. One end of the second curing sheet 29 is connected to the pulley 31 via the wire 31a, and the other end of the second curing sheet 29 hangs down from the upper end of the guide rail 19 (suspended guide section) between the guide rail 19 and the piece 125. The pulley 31 may be omitted and one end of the second curing sheet 29 may be directly connected to a part of the frame 7 via the wire 31a. The second curing sheet 29 is a long strip having a width in the X direction approximately equal to that of the first curing sheet 27, and the length of the second curing sheet 29 is approximately equal to the height of the rectangular cross section 125a (FIG. 3(a)) of the piece 125. The width of the first curing sheet 27 and the second curing sheet 29 in the X direction is set wider than the width of the cutting groove formed in the piece 125 by the cutting section 9a.

The operation of the cutting device 1 in the cutting process as described above will be described. As shown in FIG. 5(a), in the cutting process of the slice 125 by the cutting device 1, the slice 125 is placed on the base 3, and the outer peripheral surface 125b of the slice 125 is arranged close to the guide rail 19. Then, while the wire saw tool 9 travels by the wire saw driving unit 11, the movable cutting unit 5 rotates toward the slice 125 by driving the hydraulic cylinder 41 (frame driving unit). Then, as shown in FIG. 5(a), the cutting part 9a of the wire saw tool 9 gradually bites into the slice 125 while cutting the slice 125. At this time, the first protective sheet 27 comes into contact with the surface of the slice 125 by its own weight with the rotation of the frame 7, and gradually covers it while deforming into a shape that conforms to the surface. In particular, the first protective sheet 27 covers the upper surface 125c and the inner peripheral surface 125d of the slice 125.

The second protective sheet 29 also moves downward along the vertical outer peripheral surface 125b of the piece 125, sliding down from the upper end of the guide rail 19 under its own weight, and covers the outer peripheral surface 125b. Note that for such movement of the second protective sheet 29, the rotation of the pulley 31 may be separately controlled by a motor or the like in accordance with the rotation of the movable cutting part 5 about the hinge shaft 3a. Furthermore, as described above, the dust collection duct 21 moves downward according to the position of the cutting part 9a under the control of the drive motor 23. Finally, as shown in FIG. 5(b), the cutting of the piece 125 is completed when the cutting part 9a completely crosses the piece 125.

Here, the cutting unit 9a, the first protective sheet 27, and the second protective sheet 29 are present on the same vertical plane, that is, on the same imaginary plane perpendicular to the rotation axis of the movable cutting unit 5. According to such a positional relationship, the first protective sheet 27 covering the surface of the slice 125 as described above covers the cutting groove 125j formed by the cutting unit 9a. The second protective sheet 29 also covers the cutting groove 125j formed by the cutting unit 9a. According to this configuration, during the cutting process, the cutting groove 125j on the surface of the slice 125 is blocked by the first protective sheet 27 and the second protective sheet 29, so that the cutting chips generated by the cutting unit 9a are prevented from passing through the cutting groove 125j and scattering outside the slice 125. Then, the cutting chips trapped in the cutting groove 125j are efficiently sucked and collected from the dust collection duct 21.

In order to efficiently obtain the above-mentioned effects, it is preferable that the first protective sheet 27 is deformed into a shape that covers the cut groove 125j along the surface of the slice 125, and the surface of the slice 125 closes the cut groove 125j without any gaps. For this reason, a material that can be deformed in one plane, such as a cable bear (registered trademark) or a chain, may be joined over the entire longitudinal direction of the upper surface of the first protective sheet 27. In addition, in order for the first protective sheet 27 to reliably cover the slice 125 as the frame 7 rotates, it is necessary to adjust the arrangement of both ends of the first protective sheet 27. For this reason, the frame 7 is provided with brackets 7a, 7b (FIG. 2, etc.) for attaching both ends of the first protective sheet 27, respectively. The positions of brackets 7a and 7b are adjusted appropriately in advance, and the first protective sheet 27 is installed so that it hangs down from both brackets 7a and 7b, so that the first protective sheet 27 reliably covers the section 125 as the frame 7 rotates.

In the case of cutting a normal cutting target, it is possible to perform wet cutting while pouring water into the cutting area to prevent the scattering of cutting chips. However, since the thermal shielding wall 105 of the reactor building 101 is radioactive, wet cutting of the thermal shielding wall 105 generates radioactive contaminated water, which requires a large burden for treating the contaminated water. Therefore, it is preferable to perform dry cutting when cutting the thermal shielding wall 105. Dry cutting has the problem that cutting chips are likely to scatter, and in particular, cutting of the thermal shielding wall 105 generates radioactive cutting chips, so there is a high need to prevent the scattering of cutting chips. In contrast, according to the cutting device 1, as described above, the presence of the first protective sheet 27 and the second protective sheet 29 prevents the cutting chips from scattering outside the cut piece 125, so it is possible to omit the installation of a protective sheet to prevent scattering that covers the cutting device 1. It is also possible to omit the process of collecting cutting chips that have scattered over a wide area.

Second Embodiment
Next, a second embodiment of the cutting device according to the present invention will be described in detail with reference to Figures 6 and 7. A cutting device 51 of this embodiment differs from the cutting device 1 in that it includes a protective sheet 53 instead of the first protective sheet 27 and the second protective sheet 29. The other configuration of the cutting device 51 is similar to that of the cutting device 1 of the first embodiment, so that the same or equivalent components are denoted by the same reference numerals in the drawings and redundant explanations will be omitted.

The protective sheet 53 is a flexible sheet arranged above the cutting portion 9a, for example a rubber sheet. The cutting portion 9a and the protective sheet 53 exist along the same vertical plane. The protective sheet 53 is arranged to connect predetermined portions of the frame 7 and hang down at both ends. The bracket 7b for attaching one end of the protective sheet 53 is arranged at a lower position on the frame 7 compared to the cutting device 1 (Figure 2). A hook portion 7c is provided at a position on the side of the frame 7 closer to the wire saw driving unit 11, and a part of the protective sheet 53 is folded and hooked on the hook portion 7c so that the protective sheet 53 does not interfere with the cutting portion 9a. The protective sheet 53 is in the form of a long strip having a predetermined width in the X direction, and the length of the protective sheet 53 is longer than the sum of twice the height and the width of the rectangular cross section 125a (Figure 3(a)) of the cut piece 125. A material that can be deformed in one plane, such as a cable bear (registered trademark) or a chain, may be attached to the entire longitudinal direction of the upper surface of the protective sheet 53. In addition, a pin 21c that protrudes in the X direction and crosses above the protective sheet 53 is provided at the top of the dust collection duct 21.

The operation of the cutting device 51 in the cutting process will be described. In the cutting process, as in the cutting device 1 of the first embodiment, the piece 125 is placed on the base 3, and while the wire saw tool 9 runs, the movable cutting part 5 rotates toward the piece 125. Then, the cutting part 9a of the wire saw tool 9 gradually cuts the piece 125 and bites into it. At this time, as the frame 7 rotates, the protective sheet 53 is dragged from the bracket 7a and covers the upper surface 125c and the inner surface 125d of the piece 125. In addition, as the dust collection duct 21 descends under the control of the drive motor 23, the pin 21c presses the protective sheet 53 downward, and the protective sheet 53 also covers the outer surface 125b of the piece 125. Here, the portion of the protective sheet 53 that was hooked onto the hook portion 7c is sent out from the hook portion 7c, so that a sufficient length of the protective sheet 53 covers the inner surface 125d, the upper surface 125c, and the outer surface 125b of the piece 125. Finally, as shown in FIG. 7, when the cutting portion 9a completely crosses the piece 125, the cutting of the piece 125 is completed.

According to the cutting device 51 described above, the protective sheet 53 covers the cutting groove 125j on the inner surface 125d, the upper surface 125c, and the outer surface 125b of the piece 125, thereby achieving the same effect as the cutting device 1 of the first embodiment.

The present invention can be implemented in various forms including the above-mentioned embodiment, with various modifications and improvements based on the knowledge of a person skilled in the art. In addition, it is also possible to configure modified examples by utilizing the technical matters described in the above-mentioned embodiment. The configurations of each embodiment may be used in appropriate combination. For example, in the cutting device 1, 51 of the embodiment, the movable cutting unit 5 rotates relative to the base 3 and the cut piece 125 so that the cutting unit 9a crosses the cut piece 125, but the cutting unit 9a may cross the cut piece 125 by translating the movable cutting unit 5 relative to the base 3 and the cut piece 125. For example, the cutting unit 9a may be parallel to the upper surface 125c of the cut piece 125, and the movable cutting unit 5 may translate in a direction perpendicular to the upper surface 125c of the cut piece 125. In addition, for example, the cutting device 1, 51 is not limited to cutting the heat shield wall 105 of the reactor building 101, and can be applied to cutting various objects to be cut.

1, 51...cutting device, 7...frame, 9...wire saw tool, 13T...cutting pulley, 19...guide rail (rail), 21...dust collection duct, 27...first protective sheet (curing sheet part, first sheet part), 29...second protective sheet (curing sheet part, second sheet part), 41...hydraulic cylinder (frame drive part), 53...curing sheet (curing sheet part), 125...piece (object to be cut), 125j...cutting groove.

Claims (4)

A frame for holding a pair of pulleys;
A wire saw tool that travels between the pulleys; and
a frame driving unit that moves the frame relatively to the object to be cut so that the object to be cut crosses between the pulleys;
a protective sheet portion that moves over the surface of the object to be cut as the frame moves relative to the object to be cut and covers the cut groove formed in the object to be cut by the wire saw tool. The curing sheet part is
The first sheet portion is made of a flexible member that connects predetermined portions of the frame and hangs down at both ends, and is provided along a virtual plane that is parallel to the movement direction of the frame relative to the cutting object and along the trajectory of the wire saw tool,
The cutting device according to claim 1 , wherein the first sheet portion comes into contact with the surface of the object to be cut and deforms along the surface as the frame moves relative to the object to be cut. The curing sheet part is
A second sheet portion is provided, the second sheet portion being made of a flexible member having one end fixed to a predetermined portion of the frame and the other end hooked onto a predetermined suspended guide portion whose position is fixed relative to the workpiece, the second sheet portion being parallel to the moving direction of the frame relative to the workpiece and existing along an imaginary plane along the trajectory of the wire saw tool,
3. The cutting device according to claim 1, wherein the second sheet portion hangs down from the suspended guide portion under its own weight so as to cover a vertical surface of the workpiece as the frame moves relative to the workpiece. The cutting device according to any one of claims 1 to 3, further comprising a dust collection duct that is provided in the vicinity of the workpiece and is movable on a rail located along the surface of the workpiece, and that moves to the vicinity of the wire saw tool.

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