JP2013141723A - Machine type cutting device for underwater environment and machine type cutting method for underwater environment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small sized and lightweight machine type cutting device for an underwater environment usable in an underwater environment such as the maintenance work of a nuclear power plant, or in a narrow portion in the underwater environment by further reducing resistance received from the water of a machining blade.SOLUTION: The surface shape of a rotary disk of a machining blade is designed so as to further reduce resistance received from the water of the machining blade, or a mechanism is provided in which the water resistance is reduced. For example, a surface of the rotary disk is subjected to dimpling, or a cover subjected to dimpling is provided at the surface of the rotary disk. Alternately, a surfactant is applied to the dimpled rotary disk surface or the dimpled cover surface, or a part of the machining blade is surrounded with a casing, and gas is supplied into the casing to partially form a gaseous environment. Furthermore, a part of the machining blade is surrounded with the casing, and a water flow or a water flow containing fine air bubbles is applied in the rotation direction of the rotary disk to assist rotation.

Description

  The present invention relates to a mechanical cutting device for underwater environment and a mechanical cutting method for underwater environment in which a disk-shaped processing blade (rotating cutter, rotating grindstone, etc.) is rotated at high speed in an underwater environment to cut, cut, or polish a processing target. In particular, the present invention relates to a mechanical cutting device for underwater environment and a mechanical cutting method for underwater environment of a radioactive structure in maintenance / remodeling work of a nuclear power plant.

  For nuclear power plant maintenance and remodeling, conventional mechanical cutting, cutting or polishing methods (hereinafter simply referred to as cutting methods), such as abrasive water jet cutting methods, disk cutter methods, and rotating grindstone methods, have been used. It is adopted from. For example, in cutting with a conventional processing blade (rotating cutter, rotating grindstone, etc.), it has been essential to strengthen and enlarge the rotational drive source so that the processing blade does not lose the resistance received from water. At the same time, in order to reduce the resistance that the machining blade receives from water, measures such as selecting a machining blade made of a material having a low friction with water and a manufacturing method have been taken.

  Patent Document 1 discloses a wire saw cutting device in which a wire saw is driven, both side surfaces of a driving pulley having an opening on a side surface are closed with a donut disk, a sealed space is provided inside, and an opening of the driving pulley is provided. A technique for reducing the rotational resistance of water in water is disclosed.

  In Patent Document 2, a wire saw is accommodated in a cylinder or a semi-cylinder, and a pressurized fluid is allowed to flow into the cylinder, or a pressurized fluid is ejected toward a guide sheep that changes the direction of the wire saw. A technique for reducing the resistance of the portion is disclosed.

JP 2010-12766 A JP-A-6-91631

  A conventional disk-shaped processing blade (hereinafter simply referred to as a processing blade) has a plurality of blades (such as a cutter or a grindstone) around a rotating plate without irregularities or holes. Conventionally, when a rotary cutting method is applied in an underwater environment, the resistance of the processing blade is particularly large compared to the air environment due to the action of the viscosity of the water, so a rotation drive source commensurate with the loss is required. In addition, when the setting space of the apparatus is narrow, there is a problem that cannot be applied due to restrictions on the size of the rotational drive source. Also, when considering the handling property in remote underwater, it is more advantageous to use a small and light device having a rotational drive source of the same size as the device in the air environment.

  Also, when the existing air cutting device is remodeled to the underwater specification and diverted for the purpose of shortening the device manufacturing period and manufacturing cost, the cutting performance is reduced due to the resistance of water, so it is received from water. Need to reduce resistance.

  In Patent Document 1, the resistance received from water is reduced by making the side surface having the opening flat with a donut-shaped disk, but in the rotary cutting method, the rotating plate already has a flat surface. There is also a need to reduce the resistance received from water.

  The technique disclosed in Patent Document 2 is effective in reducing the resistance received from the water of a small-sized guide sheep that changes the direction of the wire saw or the wire saw, but it is a large disk-shaped processing blade that itself is involved in cutting. It is not effective in reducing the resistance received from water.

Accordingly, a first object of the present invention is to further reduce the resistance that the disc-shaped processing blade receives from water, and to use the underwater environment mechanical cutting device or the underwater environment that can be used in an underwater environment such as maintenance work of a nuclear power plant. A mechanical cutting method is provided.
The second object of the present invention is to provide a small and lightweight underwater environment mechanical cutting device or underwater environment mechanical cutting method that can be used in narrow spaces underwater environments such as maintenance work of nuclear power plants. It is to be.

  In order to achieve one of the above objects, the present invention provides a mechanism for devising the surface shape of the rotating plate of the processing blade or reducing water resistance. More specifically, a device or mechanism as described below may be provided.

  First, the surface of a disk-shaped working blade having a plurality of blades around a rotating plate without an opening is subjected to dimple processing, or the rotating plate is sandwiched by a disk-shaped cover subjected to dimple processing. Thereby, boundary layer peeling with the water which arises on the surface of a rotating plate is suppressed, and the resistance which a rotating plate receives is reduced. Further, by coating the surface of the rotating plate with a surfactant, friction between the rotating plate and water is reduced, and the resistance that the rotating plate receives from water is reduced.

  Second, a housing that partially covers the processing blade during processing is provided, and a gas such as air is supplied into the housing to partially create an air environment, thereby reducing water resistance. Moreover, the gas released into the underwater environment is reduced by moving the housing following the movement of the processing blade and stopping the housing when it contacts the processing target.

  Third, a housing that partially covers the processing blade at the time of processing is provided, and rotation is assisted by providing a water flow or a water flow containing fine air bubbles in the direction of rotation of the processing blade. In addition, a plurality of protrusions are provided on the surface of the rotating plate or a disc-shaped cover fixed to the rotating plate so that the protrusion receives a water flow, thereby reducing the shear resistance of water.

ADVANTAGE OF THE INVENTION According to this invention, the resistance received from the water of a processing blade can further be reduced, and the mechanical cutting apparatus or the mechanical cutting method for underwater environments which can be used in underwater environments, such as maintenance work of a nuclear power plant, can be provided.
Further, according to the present invention, it is possible to provide a small and lightweight mechanical cutting device for underwater environment or a mechanical cutting method for underwater environment that can be used in narrow spaces underwater environment such as maintenance work of a nuclear power plant.

It is the figure which showed embodiment which cut | disconnects a fuel storage rack in the spent fuel pool of a nuclear power plant. It is a figure which shows the 1st Example of the rotary cutter type cutting device which is one Embodiment of this invention. It is a figure which shows the cutting method by the rotary cutter type cutting device which is one Embodiment of this invention. It is a figure which shows the rotary cutter in a 1st Example. It is a figure which shows the rotary cutter in a 2nd Example. It is a figure which shows the 3rd Example of the rotary cutter type cutting device which is one Embodiment of this invention. It is a figure which shows the 4th Example of the rotary cutter type cutting device which is one Embodiment of this invention. It is a figure which shows the 5th Example of the rotary cutter type cutting device which is one Embodiment of this invention. It is a figure which shows the 6th Example of the rotary cutter type cutting device which is one Embodiment of this invention.

  As an embodiment of the mechanical cutting device for underwater environment of the present invention, a rotary cutter type cutting device using a rotary cutter as a processing blade of a fuel storage rack 2 in a spent fuel pool 1 of a nuclear power plant whose concept is shown in FIG. The cutting by 3 will be described. Of course, the processing object may be cut, cut, or polished using a rotating grindstone or the like as the processing blade.

  A plurality of fuel storage racks 2 to be cut by the rotary cutter type cutting device 3 are arranged in the spent fuel pool 1 filled with water 4, and the rotary cutter type cutting device 3 is arranged between the fuel storage racks 2. It is installed on the floor surface of the spent fuel pool 1 remotely from a cart 6 installed on the working floor 5 in a small space.

The rotary cutter type cutting device 3 is remotely operated from an operation unit 7 installed on the work floor 5 and operates by electric power and driving fluid supplied from the operation unit 7 through cables and hoses 8.
Hereinafter, the Example of the rotary cutter type cutting device 3 in embodiment shown in FIG. 1 is described.

Example 1
The 1st Example of the rotary cutter type cutting device 3 which is embodiment of this invention is shown in FIG.
2 is a top view of the rotary cutter type cutting device 3 as seen from above, and the lower figure of FIG. 2 is a side view of the rotary cutter type cutting device 3 as seen from the direction of a transverse axis drive motor 19 described later. It is.

  The rotary cutter 9 is attached to a shaft 11 that rotates at high speed in the direction of an arrow a by the rotation of a motor 10 for rotation driven by water, air flow, or electricity by water or a highly viscous fluid. The cutter base 12 that holds the shaft 11 and the rotation motor 10 has a structure that can move on a front and rear axis guide 14 that is fixed on the traversing base 13. The front and rear axis that is rotated by driving the front and rear axis drive motor 15. The ball screw 16 can travel in the direction of arrow b. The traverse base 13 has a structure that can move on a traverse axis guide 18 fixed on the main body base 17, and can travel in the direction of arrow c by a traverse axis ball screw 20 that rotates by driving of a traverse axis drive motor 19. It is.

A method of cutting the cutting target 21 existing in water using the rotary cutter type cutting device 3 will be described with reference to FIG.
First, the rotary motor 9 is rotated at a high speed in the cutting direction of the arrow a by the rotation motor 10, and then the rotary cutter 9 is advanced to the predetermined position in the direction of the arrow b by the operation of the front and rear axis drive motor 15.
Next, the cutting object 21 is cut by advancing the rotary cutter 9 in the direction of arrow c by driving the transverse axis driving motor 19.

FIG. 4 shows the rotary cutter 9 in the first embodiment.
The rotary cutter 9 of the rotary cutter type cutting device 3 shown in FIG. 1 has a rotary plate 9a having two surfaces orthogonal to the shaft 11 that is the rotary shaft, and a blade 9b provided around the rotary plate. In the first embodiment, minute dimple processing is performed on two surfaces of the rotating plate 9a. The dimple 22 disturbs the water flow on the surface of the rotating plate 9a, suppresses separation of the boundary layer between water and the rotating plate 9a, and reduces the resistance received by the rotating plate 9a. Although not shown in the drawing, the frictional resistance between the rotary cutter 9 and the water 4 can be reduced by coating the two surfaces of the rotating plate 9a with a surface active agent instead of the dimple processing surface. The resistance due to the viscosity of water can be reduced.

(Example 2)
FIG. 5 shows a rotary cutter 9 in the second embodiment.
In the rotary cutter type cutting device 3 shown in FIG. 1, as shown in FIG. 5, the rotary plate 9 a of the rotary cutter 9 is sandwiched with a disk-shaped cover 23 whose surface is dimple processed, and is fixed to the shaft 11. By rotating the cutter 9 and the cover 23 at the same time, the same effect as in the first embodiment can be obtained. Similarly to Example 1, surface peeling is promoted by applying a dimple processed surface or a surface coated with a surfactant instead of dimple processing, or applying periodic vibration such as ultrasonic vibration. The resistance of water may be reduced by using the cover 23 having a structure.

  In the first and second embodiments, the resistance of water can be reduced by devising the two surfaces of the rotary cutter 9, but the third to fifth embodiments described below have a systematic mechanism in the rotary cutter type cutting device 3. This is an example in which the resistance of water can be reduced by adding.

(Example 3)
FIG. 6 shows a third example of the rotary cutter type cutting device 3 according to the embodiment of the present invention.

  In the third embodiment, on the cutter base 12 of the rotary cutter type cutting device 3 shown in FIG. 2, the rotary opening 24a around which the rotary cutter 9 rotates and the lower surface that enables the shaft 11 (the rotary cutter 9) to move in the forward direction. A housing 24 provided with a shaft opening 24b provided in is provided to partially cover the rotary cutter 9. Air is supplied from an air supply facility provided in the operation unit 7 installed on the work floor 5 in the air to the casing 24 through an air supply hose 25 constituting the boses 8. By supplying air, the water in the casing 24 is removed (purged), and an air layer is partially formed on a part of the rotary cutter 9 so that friction with water does not occur on the surface of the rotary cutter 9. Since an area is formed, the resistance of water corresponding to the area can be reduced.

  In this method, air is released from the gap between the casing 24 and the cutting object 21 and from the cutting groove. However, when the activated structure in the nuclear power plant is cut, this air is radioactive. There is a concern that the atmospheric dust on the work floor 5 may be increased, and a gas recovery hood 31 is provided above the rotary cutter type cutting device 3 to efficiently recover the released air. Need to be purified.

  When an air motor is used as the rotation motor 10 of the rotation drive source of the rotary cutter 9, the system may be simplified by opening the exhaust of the drive air into the housing 24 and diverting it as purge air.

Example 4
FIG. 7 shows a fourth example of the rotary cutter type cutting device 3 according to the embodiment of the present invention.

  In the configuration of the third embodiment, since the casing 24 does not move, that is, is fixed, a large amount of air is discharged from between the rotary cutter 9 and the casing 24. The fourth embodiment includes a cover slide mechanism 26 that can move the rotary cutter 9 and the casing 24 separately, as shown in FIG. 7, in order to avoid the release of a large amount of air. The cover slide mechanism 26 includes a guide rail 26r fixed to the lower surface of the housing 24, a spring 26b, and a shaft opening 24b provided on the lower surface of the housing 24 and through which the shaft 11 moves.

  When the cutter base 12 is advanced from the state shown in the upper diagram of FIG. 7 and the casing 24 comes into contact with the cutting target member 21, the casing 24 cannot move forward and stops. On the other hand, the rotary cutter 9 continues to move forward even after the housing is stopped, and can start processing.

  As a result, the gap between the casing 24 and the cutting object 21 can be eliminated during processing, and the amount of air released can be reduced.

  In addition, the shaft opening 24b through which the shaft 11 on the lower surface of the housing 24 moves may have a bellows structure, for example, so that the amount of air released can be further reduced.

  Furthermore, in Example 3 or Example 4, what is supplied to the casing 24 is not air but may be other gas.

(Example 5)
FIG. 8 shows a fifth example of the rotary cutter type cutting device 3 according to the embodiment of the present invention.
The fifth embodiment is an example in which the resistance of water received by the rotary cutter 9 is reduced by the water flow that assists the rotation of the rotary cutter 9, unlike the third and fourth embodiments in which the rotary cutter 9 is covered with the casing 24.

  In the fifth embodiment, a casing 27 having a water flow opening 27 a in the forward direction of the rotary cutter 9 is provided on the cutter base 12 of the rotary cutter type cutting device 3 shown in FIG. 2 to partially cover the rotary cutter 9. In the fifth embodiment, the jet nozzle 28 is provided in the casing 27 to create a water flow in the same direction as the rotation direction of the rotary cutter 9, thereby reducing the resistance of water received by the rotary cutter 9. Water is supplied from a water supply pump provided in an operation unit 7 installed in the work floor 5 or the spent fuel pool 1 through a water supply hose 29 constituting the hoses 8.

  Since the peripheral speed in the diameter direction varies depending on the diameter of the rotary cutter 9, the nozzle hole diameter may be adjusted according to the position of the jet nozzle 28. You may reduce the resistance of the water which the rotary cutter 9 receives by adding a fine air bubble to water and supplying a jet.

(Example 6)
FIG. 9 shows a sixth example of the rotary cutter type cutting device 3 according to the embodiment of the present invention.
In the sixth embodiment, instead of the disk-shaped cover 23 in which the surface shown in the second embodiment is subjected to dimple processing, a cover 30 with a protrusion having a protrusion 30t that promotes rotation is added to the apparatus configuration of the fifth embodiment. It is provided on at least one side of the rotating plate 9a. The energy of the jet flow from the jet nozzle 28 can be received by the protrusion 30t, and can be used for reducing the load on the cutter rotating motor 10.
When providing the cover 30 with a protrusion only on one side, the cover 23 of Example 2 may be provided on the other side.

(Example 7)
Example 7 is an example in which the technique of Example 1 or 2 described above is used in combination with the technique of Example 3 to 4 or Example 5.
Also in Example 7, resistance due to the viscosity of water can be reduced.

According to the embodiment described above, the resistance received from the water of the processing blade can be further reduced, and a mechanical cutting device or a mechanical cutting method for underwater environment that can be used in an underwater environment such as maintenance work of a nuclear power plant can be provided. .
In addition, according to the embodiment described above, a rotary drive source of the same size as the rotary drive source of the air size can be used for underwater cutting, so it is used in a narrow part under an underwater environment such as maintenance work of a nuclear power plant. A possible small and lightweight mechanical cutting device for underwater environment or a mechanical cutting method for underwater environment can be provided.

1: spent fuel pool 2: fuel storage rack 3: rotating cutter type cutting device 4: water 5: work floor 6: cart 7: operation unit 8: cables and hoses 9: rotating cutter 9a: rotating plate 9b: blade 10 : Motor for cutter rotation 11: Shaft 12: Cutter base 13: Traverse base 14: Front / rear axis guide 15: Motor for front / rear axis drive 16: Front / rear axis ball screw 17: Main body base 18: Traverse axis guide 19: Motor for traverse axis drive 20: Traverse axis ball screw 21: Member to be cut 22: Dimple 23: Cover 24: Housing 24a: Rotating opening 24b: Shaft opening 25: Air supply hose 26: Cover slide mechanism 26b: Spring 26r: Guide rail 26s: Slider 27: Housing 27a: Water flow opening 28: Jet nozzle 29: Water supply hose 30: Cover with protrusion 30t: Protrusion 31: Hood for gas recovery

Claims (11)

A disk-shaped processing blade having a plurality of blades around a rotating plate without an opening, and a processing blade moving means for moving the processing blade so that a processing target can be processed; In an underwater environment mechanical cutting device for performing the treatment of rotating or cutting or cutting or polishing the workpiece,
A mechanical cutting device for underwater environment, comprising water resistance reducing means for reducing water resistance of the rotating plate. The mechanical cutting device for underwater environment according to claim 1,
The water resistance reducing means is a mechanical cutting device for underwater environment, wherein the surface of the rotating plate is provided with at least one of dimple processing and surfactant coating. The mechanical cutting device for underwater environment according to claim 1,
The water resistance reducing means is a mechanical cutting device for underwater environment characterized in that the rotating plate is sandwiched by a disk-shaped cover provided with at least one of dimple processing and surfactant coating. The mechanical cutting device for underwater environment according to claim 1,
The underwater environment mechanical cutting device characterized in that the water resistance reducing means includes a casing that partially covers the processing blade during processing, and a holding means that holds the inside of the casing in an air environment. The mechanical cutting device for underwater environment according to claim 4,
The underwater environment mechanical cutting device characterized in that the water resistance reducing means includes casing moving means for moving the casing following the movement of the processing blade. The mechanical cutting device for underwater environment according to claim 1,
The water resistance reducing means provides a casing that partially covers the processing blade during processing, and a rotation that assists the rotation by providing a water flow or a water flow containing fine air bubbles in the direction of the rotation of the processing blade. A mechanical cutting device for underwater environment characterized by having auxiliary means. The mechanical cutting device for underwater environment according to claim 6,
The water resistance reducing means has a plurality of protrusions provided on a surface of the rotating plate or a disk-shaped cover fixed to the rotating plate, and the rotation assisting means allows the protrusion to receive the water flow. A mechanical cutting device for underwater environment. A disk-shaped processing blade having a plurality of blades around a rotating plate without an opening is moved so that the processing target can be processed, and the processing target is cut or cut or polished by rotating the processing blade in an underwater environment. In the mechanical cutting method for underwater environment for performing the treatment,
A mechanical cutting method for an underwater environment, comprising a water resistance reduction step of reducing the resistance of water of the rotating plate. The mechanical cutting method for underwater environment according to claim 8,
A mechanical cutting method for an underwater environment, wherein the processing blade is partially covered with a casing during processing, and the water resistance reducing step includes a holding step for maintaining the inside of the casing in an air environment. The mechanical cutting method for underwater environment according to claim 9,
The water resistance reducing step includes a casing moving step of moving the casing following the movement of the processing blade. The mechanical cutting method for underwater environment according to claim 8,
The processing blade is partially covered with a housing at the time of processing, and the water resistance reduction step is a rotation assist that assists the rotation with a water flow in the direction of the rotation of the processing blade or with a water flow containing fine air bubbles. A mechanical cutting method for an underwater environment, comprising a step.

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