JP4436769B2 - Underwater moving device - Google Patents

Description

  The present invention relates to an underwater moving device, and more particularly to an underwater moving device that can move along the surface of a structure in water.

  For example, a nuclear reactor currently used in a power plant or the like is usually operated in a state where nuclear fuel such as uranium is stored in a predetermined pressure vessel and pressurized in water. In the case of a boiling water reactor, the pressure at this time reaches a maximum of about 7 megapascals.

  For this reason, strict safety is required for the nuclear pressure vessel, and inspection and inspection are indispensable not only for the pressure vessel itself but also for various structures and devices in the vessel such as a shroud (core bulkhead).

  Such inspection (including inspection) in the reactor pressure vessel is performed with the vessel opened. At this time, the inside of the container is in a strong radioactive environment. For this reason, it is customary to carry out the inspection with water (cooling water) in the container.

  For this reason, the inspection is generally performed by an inspector remotely operating an underwater TV camera or the like using an operation jig or the like.

  Also, a method has been proposed that uses an underwater mobile device that can be operated remotely, is equipped with equipment necessary for inspection and inspection, such as an ultrasonic flaw detector, and is moved to the part to be inspected for inspection. Yes. In this method, it is necessary to bring an inspection instrument such as an ultrasonic flaw detector close to a target part to some extent at the time of inspection.For this reason, including vertical and almost vertical parts such as the outer wall surface of the shroud It is necessary to move along the surface.

As such a moving device, it is equipped with a thrust fan and a skirt, which generates a force that attracts the device main body to the surface to be inspected, thereby enabling it to move along an underwater slope, vertical surface, etc. Have been proposed (see, for example, Patent Document 1).
JP-A-8-179079

  When the suction force is generated in the underwater moving device by the thrust fan and the skirt and is absorbed on the wall surface, it is necessary to discharge the water inside the skirt with the thrust fan to obtain a lower pressure inside the skirt than the outside. In order to maintain this state, it is necessary to continue draining the water inside the skirt and continuously sucking the water outside the skirt from the flow path between the skirt and the wall surface.

  If this amount of suction is stable in relation to the amount of water discharged inside the skirt, a stable adsorption force can be obtained. However, in the above prior art, there is a water inlet to the inside of the skirt between the skirt and the wall surface, and since this skirt is a flexible material, the amount of suction changes due to deformation of the skirt and fluctuation of the wall surface state. To do. The suction force on the wall surface of the underwater moving device varies due to the change in the suction amount.

  This invention is made | formed in view of these problems, and provides the underwater moving apparatus which can acquire the stable adsorption | suction force with respect to a wall surface.

  In order to solve the above problems, the present invention employs the following means.

  A thruster unit composed of a bottom plate member constituting the base of the underwater movement device, a pump attached to one side of the bottom plate member and discharging water sucked from the bottom surface side of the bottom plate member to the top surface side, and a bottom plate member of the bottom plate member A skirt member attached to the outer periphery, a wheel attached to at least three points of the bottom plate member, and a wheel for movably supporting the underwater movement device on the movement target surface, and the other side of the bottom plate member to which the thruster unit is not attached In an underwater moving apparatus that includes an attached suction duct and moves on the movement target surface by the wheel while being adsorbed to the movement target surface in water by the thruster unit and the skirt member, a set comprising the thruster unit and the suction duct. Is arranged in parallel with the bottom plate member, and between the juxtaposed thruster units, there is a stationary blade that rectifies the water flow. The wheel is arranged outside the water formed by the suction duct and the thruster unit.

  Since this invention is equipped with the above structure, it can acquire the stable adsorption | suction force with respect to a wall surface with a thrust fan etc.

  Hereinafter, the best embodiment will be described with reference to the accompanying drawings. FIG. 1 is a diagram illustrating an underwater mobile device (ROV: Remotely Operated Vehicle) according to an embodiment of the present invention. FIG. 1 (a) is a front view, and FIG. 1 (b) is a side view. It is sectional drawing. FIG. 2 is a diagram illustrating an example in which the underwater moving device ROV shown in FIG. 1 is applied to the shroud 61 in the reactor pressure vessel 60.

  As shown in the figure, the underwater moving device ROV includes a bottomed box-shaped main body structure portion including a bottom plate portion 1, a left frame portion 2, a right frame portion 3, an upper frame portion 4, and a lower frame portion 5. . The bottom plate portion 1, the left frame portion 2, the right frame portion 3, the upper frame portion 4, and the lower frame portion 5 are main body members constituting the main body structure portion.

  In the drawing, the bottom plate portion 1 is drawn so as to be vertical. For this reason, in the front view shown in FIG. 1A, the upper side of the paper surface is the upper frame portion 4 side of the main body structure portion, and in the side sectional view of FIG. The right side is the bottom plate 1 side. Here, in these drawings, the description will be continued on the assumption that the upper side is the front part or the front direction of the underwater moving apparatus and the lower side is the rear part or the rear direction.

  The bottom plate portion 1 is a substantially square (square or rectangular) plate material, and the left frame portion 2, the right frame portion 3, the upper frame portion 4, and the lower frame portion 5 are joined to each side as strength members. Thereby, the whole main-body structure part is made as a bottomed, substantially rectangular box, and given rigidity is given. In addition, thruster units 6 and 7 are attached to the rear end inside the bottom plate portion 1 side by side.

  As the thruster units 6, 7, so-called ducted axial flow pumps having a screw propeller type impeller in a cylindrical duct as shown in the figure are used. As shown in the side sectional view of FIG. 1B, the duct passes through the bottom plate 1 and is attached so that the outside (bottom side) and the inside (top side) of the box communicate with each other. Yes. The thruster units 6 and 7 include motors 8 and 9 and an impeller, respectively. The impellers are rotationally driven by the motors 8 and 9 by a so-called rim drive (ring portion peripheral drive) system.

  In the lower part of the bottom plate part 1, rear wheel tires 10 and 11 are provided with the rotation axis horizontal. The rear wheel tire is held in a state of projecting almost half from the bottom plate portion 1 to the outside as shown in FIG. The rear wheel tires 10 and 11 are provided with motors 12 and 13, respectively, and rotate and drive the respective rear wheel tires via a gear mechanism. The rotation speed at this time is detected by the encoders 14 and 15, respectively.

  The rear tires 10 and 11 can each be adjusted in rotation speed, and can be turned straight while traveling while turning, or turned when stopped, by adjusting the difference between the left and right rotation speeds. A front wheel ball caster 16 is provided at the upper portion of the bottom plate 1 so as to be free (can freely rotate). As shown in the side sectional view of FIG. 1B, the front wheel ball caster is held in a state of projecting almost half from the bottom plate portion 1 to the outside.

  As described above, the underwater moving device is equipped with the front wheel ball caster 16 and the rear wheel tires 10 and 11 as wheels.

  On the other hand, a skirt member 17 is attached to the outer periphery of the bottom plate portion 1 so as to extend further outward (right side in FIG. 1B) from the surface of the bottom plate portion 1. The skirt member 17 is represented by a two-dot chain line in FIG. 1A and has a substantially rectangular planar shape. The skirt member 17 is made of, for example, an elastic rubber material reinforced with polyamide fiber (trade name nylon), and is opposite to the end attached to the periphery of the bottom plate portion 1, that is, FIG. As shown in (b), an edge 17a having a round cross section is applied to the end that comes in contact with the wall surface W to be inspected.

  As shown in FIG. 1, in this example, the underwater mobile device ROV is equipped with an ultrasonic flaw detector 18 as an inspection device. The ultrasonic flaw detector 18 is provided on the upper frame 4 and is connected to the main body of the ultrasonic flaw detector outside via a cable C described later. Although not shown, the ultrasonic probe 18 is held by a nut member (ball nut member) screwed into the ball screw 19, and is indicated by arrows L and R by rotating the ball screw 19. As shown in FIG. The ball screw 19 is configured to be rotationally driven by a motor 20 via a gear mechanism, the left / right movement position is detected by an encoder 21, and the movement range is limited by limit switches 22 and 23.

  The underwater moving device ROV needs to minimize the influence of the center of gravity and the moment caused by the buoyancy in the case where positioning weaving such as ultrasonic flaw detection is important. For this reason, buoyancy bodies 24 and 25 of appropriate sizes are attached so that the center of gravity of the apparatus and the buoyancy center are as close as possible. As the buoyancy bodies 24 and 25, those obtained by subjecting cuboidal lumps such as expanded polystyrene to surface treatment may be used.

  The underwater moving device needs to know the position in the water and the position in the depth direction. In the example of FIG. 1, an inclination angle sensor box 26 is provided between the thruster units 6 and 7, and a water depth sensor box 27 is provided above the right frame portion 3. The inclination angle sensor box 26 accommodates four inclination angle sensors 28, 29, 30, and 31, and the water depth sensor box 27 accommodates a water depth sensor 32 and a water depth sensor amplifier 33.

  The inclination angle sensors 28, 29, 30, and 31 share and measure the rotation angle of the underwater movement device 90 ° in a state of being attracted to the vertical wall surface as shown in FIG. The water depth sensor 32 detects the water pressure, and the water depth can be calculated by the water depth sensor amplifier 33.

  The underwater mobile device ROV is a wired remote control system, and therefore includes a connector box 34 to which a remote operation cable C is connected.

  Next, the suction ducts 35 and 36 that are features of the present embodiment will be described. The suction ducts 35 and 36 are used as water absorption passages. That is, the suction ducts 35 and 36 are cylindrical water absorption passages formed so as to be in contact with the inside of the upper frame portion 4 (in the case of the upper frame portion 4, the lower side thereof). And these suction ducts 35 and 36 penetrate the bottom plate part 1, as shown in the side sectional view of FIG. 1B, and the inside (left side in FIG. 1B) and the outside (FIG. 1). 1 (b) on the right side).

  Next, the operation of the underwater moving device ROV will be described. Here, as shown in FIG. 1, the underwater moving device is equipped with an inspection device such as an ultrasonic probe 18, the inspection object is a shroud 61 in the reactor pressure vessel 60, and the outer wall surface W of the shroud is It demonstrates as what is a wall surface to be examined.

  As described above, various structures and equipment are accommodated in the reactor pressure vessel in addition to the uranium fuel. In FIG. 2, only the shroud 61, the jet pump 63, and the shroud support 62 are provided. It is shown. It is assumed that the pressure vessel 60 is filled with cooling water. Further, the tip end of the skirt member 17 is disposed so as to be positioned in the vicinity of the inspection target wall surface W of the shroud.

  In FIG. 2, the ultrasonic contact 18 on the upper side in FIG. 1B is seen in front of the page, and the front tires 10 and 11 that are also on the left and right are seen side by side. A cable C is connected to the underwater mobile device ROV, and a remote operation unit (not shown) is connected to the other end of the cable C.

  In the operation of the underwater moving device ROV, first, in the state of FIG. 2, the thruster units 6 and 7 are driven, and the impellers are rotated in the direction in which water is sent out in front of the paper surface of FIG. . When water is sent out from the thruster units 6 and 7 to the near side, the underwater moving device ROV tries to move to the right side in FIG. 1B due to the reaction force, and the skirt member 17 contacts the wall surface W to be inspected more strongly. It becomes like this.

  Thus, a space S defined by the bottom plate portion 1, the skirt member 17, and the inspection target wall surface W is formed. The height h of the space S is determined by the rear wheel tires 10 and 11 and the front wheel ball caster 16 contacting the inspection target wall surface W. That is, the bottom plate portion 1 functions as a main body member that holds the thruster units 6 and 7 and the skirt member 17 and forms a space S partitioned with the skirt member 17 between the bottom wall portion W and the inspection target wall surface W.

  From this space S, water is sucked out by the thruster units 6 and 7. That is, water is sucked through the water supply ducts 35 and 36 and flows in the space S in the direction of arrow F. Thereby, the space S has a negative pressure, and a suction force having a predetermined strength acts between the underwater moving device ROV and the wall surface W to be inspected. Accordingly, the rear wheel tires 10 and 11 and the front wheel ball caster 16 are pressed against the wall surface W to be inspected with a predetermined force, and the underwater moving device ROV does not move unnecessarily.

  In use, the thruster units 6 and 7 are driven to perform wired remote operation using the cable C in a state where suction force is generated. That is, the rear wheel tires 10 and 11 are driven to move the underwater moving device ROV to an arbitrary location on the inspection target wall surface W, and inspection by the ultrasonic probe 18 is started. At this time, the driving force by the rear wheel tires 10 and 11 can be set larger than the friction by the skirt member 17 by setting the suction force to have a predetermined strength. As a result, the underwater moving device ROV can slide on the inspection target wall surface W.

  For example, when the rear tires 10 and 11 are rotationally driven by the motors 12 and 13, the underwater moving device ROV can be moved back and forth along the wall surface W to be inspected. The forward and backward movement directions at this time are determined by the rotation direction of the rear tires 10 and 11, and the travel distance can be obtained from the detection values of the encoders 14 and 15. Further, by controlling the motors 12 and 13 to make a difference in the rotational speeds of the rear tires 10 and 11, the traveling direction can be changed to the left and right, and the turning direction at this time is detected by the inclination angle sensors 28 to 31. You can know from the value.

  That is, the traveling operation obtained by the underwater moving device ROV corresponds to a two-wheel drive two-wheel turning type and a three-wheeled vehicle having one posture auxiliary wheel. Since the underwater moving device ROV is a so-called three-point support, it is not necessary to separately provide a suspension mechanism (suspension mechanism). Moreover, even if there is some unevenness on the wall surface W to be inspected, all the wheels are always pressed against the wall surface, and in this state, the vehicle can travel without being lifted from the wall surface not only on the horizontal plane but also on the vertical plane. .

  As described above, the underwater moving device ROV is controlled by the remote control unit outside the pressure vessel via the cable C (not shown). For this reason, various information required for remote control is brought to this remote control unit from the underwater mobile device ROV.

  First, the travel speed and travel distance of the underwater mobile device ROV can be obtained from the information detected by the encoders 13 and 14, and the travel direction can be obtained from the information detected by the inclination angle sensors 28-31. The position of the mobile device ROV can be determined. Thereby, the user can arbitrarily set the flaw detection direction by the ultrasonic probe 18 according to the situation of the wall surface W to be inspected.

  Moreover, since the depth in water of the underwater mobile device ROV is given from the information detected by the water depth sensor 30, the position of the underwater mobile device ROV can be determined more accurately by using this in combination. .

  As a result of the remote operation using the remote control unit, when the underwater mobile device ROV moves to the required location, the process proceeds to the inspection of the shroud, and the ultrasonic probe 18 is scanned in the left-right direction as necessary (scanning). ) And inspection by an ultrasonic flaw detector is started. In addition, by controlling the rotation of the motor 20 based on the information detected from the encoder 21 and the signals from the limit switches 22 and 23, fine position adjustment in the left-right direction during scanning of the ultrasonic probe 18 can be safely performed. Can be done.

  What is important for such remote operation is that the underwater moving device ROV can move smoothly along the wall surface W to be inspected. For this purpose, it is a requirement that the skirt member 17 is stably in contact with the wall surface W to be inspected with an appropriate force. For this reason, the water supply ducts 35 and 36 are provided in the example of a figure. As a result, a water flow F is generated in the space S, and a suction force is generated by the water flow F. Thereby, said requirements are satisfied and the underwater moving apparatus ROV can be smoothly moved along the inspection target wall surface W.

  This is because the state and strength of the water flow F formed by the water taken in from the water supply ducts 35 and 36 are once determined after the shapes and mounting positions of the thruster units 6 and 7 and the water supply ducts 35 and 36 are determined. This is because it is almost uniquely determined only by the operating state of the thruster units 6 and 7, and there is almost no room for including unstable elements.

  Therefore, according to the present embodiment, the suction force by the thruster unit and the skirt member can be stably obtained, and can thereby be moved smoothly in water, which is suitable for inspection in the reactor pressure vessel and the like. An underwater moving device can be provided easily.

  FIG. 3 is a view for explaining the adsorption structure of the underwater moving device ROV. FIG. 3A is a view showing an example in which the thruster units 37 and 38 are arranged near the central axis of the main body member 39, and FIG. FIG. 5 is a view showing an example in which a water absorption duct 40 is arranged on the opposite side of the thruster units 37 and 38 with respect to the central axis of the main body member 39.

  The length of the flow path of the water flow F that appears in the space S of the underwater moving device ROV is related to the strength of the suction force. In general, the longer the flow path is, the more uniform the water flow, the stronger the suction force.

  In FIG. 3A, the thruster units 37 and 38 are disposed near the central axis of the main body member 39, and the water absorption ducts 40 and 41 are disposed substantially symmetrically with respect to the central axis of the main body member. Further, the front wheel tire 42 is disposed near the center of the water absorption duct 40, and the rear wheel tire 43 is disposed near the end of the water absorption duct 41.

  In FIG. 3B, the thruster units 37 and 38 are arranged on one side of the main body member with respect to the central axis of the main body member 39, and a guide (static blade) 44 is provided between the thruster units 37 and 38. . Further, the water absorption duct 40 is disposed on the opposite side of the thruster units 37 and 38 with respect to the central axis of the main body member 39. Further, the front wheel tire 42 is disposed near the center of the water absorption duct 40, and the rear wheel tire 43 is disposed at the end of the main body member near the thruster units 37 and 38, respectively.

  In the structure shown in FIG. 3A, the water flow F formed by the water taken in from the water absorption duct 40 flows from the left to the right toward the thruster units 37 and 38 disposed near the central axis of the main body member 39. Further, the water flow F formed by the water taken in from the water absorption duct 41 flows from the right to the left toward the thruster units 37 and 38 on the paper surface. As a result, the water flow collides with the water taken in from the water absorption duct 40 and the water taken in from the water absorption duct 41, a stable water flow cannot be obtained, and the water flow becomes non-uniform.

  Further, since the intermediate water flow F between the thruster units 37 and 38 is alternately sucked with a certain period due to a small difference in the rotational speed of the thruster units 37 and 38, a stable water flow cannot be obtained. Further, since the front wheel tire 42 is located near the center of the water absorption duct 40 and the rear wheel tire 43 is located near the end of the water absorption duct 41, the flow path of the water flow F taken from the water absorption ducts 40, 41 is obstructed. As a result, a stable water flow cannot be obtained.

  In the structure shown in FIG. 3B, the water flow F formed by the water taken in from the water absorption duct 40 is because the thruster units 37 and 38 are arranged on the opposite side with respect to the central axis of the main body member 39. , It will flow a long distance and can form a stable flow. Furthermore, by providing a guide (static blade) 44 in the middle of the thruster units 37 and 38, a stable flow can be obtained without being affected by a minute rotational speed difference between the thruster units. The rotation direction of the impeller of the thruster unit is that the impeller located at the left end in the water flow direction is a clock as seen from the discharge port side (inside the box) of the impeller, as indicated by an arrow A in FIG. In the direction, the impeller located at the right end in the water flow direction may be set counterclockwise.

  Further, since the front tire 42 and the rear tire 43 are arranged so as not to obstruct the flow path formed by the water flow F taken in from the water absorption duct 40, a stable flow can be obtained.

  FIG. 4 is a diagram showing a cross section of the thruster unit. FIG. 5 is a view showing a plane of the thruster unit, FIG. 5 (a) is a cross-sectional view taken along line AA in FIG. 4, and FIG. 5 (b) is a view showing a cross-sectional view taken along line BB in FIG. Since the thruster units 6 and 7 have the same configuration, only one thruster unit will be described. As described above, the thruster unit 6 is a ducted axial flow pump. As shown in FIGS. 4 and 5, a cylindrical duct 50 is provided, and a ring 52 is attached to the outer periphery of an impeller 51 provided in the duct. In the example shown in the figure, the impeller 51 is a screw propeller type having four blades (blades) 53, and the impeller 51 has an outer periphery of the blade 53 so as to cover the four blades 53 and the outer periphery of the blade 53. A cylindrical ring 52 fixed to the end is provided.

  The shaft 54 of the impeller is supported by bearings 55 and 56. Further, the outer peripheral surface of the ring 52 is set so as to keep a gap G as narrow as possible with respect to the inner peripheral surface of the duct in the duct 50. The reason why the gap G is narrowed is to prevent backflow from occurring in the periphery of the impeller 51.

  Further, since the thruster unit 6 is driven by the rim drive system as described above, the ring gear 57 is provided on the outer periphery of the ring 52, and the spur gear 58 is engaged with the ring gear 57. For this reason, as shown in FIG. 4, the inner diameter of the portion facing the ring gear 57 on the inner peripheral surface of the duct 50 is increased. The spur gear 58 is connected to the shaft of the motor 9 via a predetermined gear mechanism (gear train). Thereby, the impeller 51 is driven by the motor 9 at a predetermined rotational speed, and the thruster unit functions as a pump.

It is a figure explaining the underwater movement apparatus concerning the embodiment of the present invention. FIG. 2 is a diagram for explaining an example in which the underwater moving device ROV shown in FIG. 1 is applied to a shroud 61 in a reactor pressure vessel 20. It is a figure explaining the adsorption | suction structure of the underwater moving apparatus ROV. It is a figure which shows the cross section of a thruster unit. It is a figure which shows the plane of a thruster unit.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bottom plate part 2 Left frame part 3 Right frame part 4 Upper frame part 5 Lower frame part 6,7 Thruster unit 8,9 Motor (for thruster unit drive)
10,11 Rear wheel tires
12,13 Motor (for driving rear wheel tires)
14,15 Encoder (for travel distance detection)
16 Front wheel ball caster 17 Skirt member 17a Edge 18 Ultrasonic probe 19 Ball screw 20 Motor (for driving ultrasonic probe)
21 Encoder (For ultrasonic probe movement distance detection)
22, 23 Limit switch 24, 25 Buoyant body 26 Inclination angle sensor box 27 Water depth sensor box 28-31 Inclination angle sensor 32 Water depth sensor 33 Water depth sensor amplifier 34 Connector box 35, 36 Suction duct 37, 38 Thruster unit 39 Main body member 40 , 41 Suction duct 42 Front wheel tire 43 Rear wheel tire 44 Stator vane (guide)
50 duct 51 impeller 52 ring 53 blade 54 shaft 55 bearing 56 bearing 57 ring gear 58 spur gear 60 pressure vessel 61 shroud 62 shroud support 63 jet pump W wall surface to be inspected

Claims (2)

A bottom plate member constituting the base of the underwater moving device;
A thruster unit comprising a pump attached to one side of the bottom plate member and discharging water sucked from the bottom surface side of the bottom plate member to the upper surface side;
A skirt member attached to the outer periphery of the bottom side of the bottom plate member;
A wheel that is attached to at least three points of the bottom plate member and supports the underwater movement device movably on the movement target surface;
A suction duct attached to the other side of the bottom plate member to which the thruster unit is not attached;
In the underwater movement apparatus that moves on the movement target surface by the wheel while being adsorbed on the movement target surface in water by the thruster unit and the skirt member,
A set of the thruster unit and the suction duct is juxtaposed to the bottom plate member, and a stationary blade for rectifying the water flow is provided between the juxtaposed thruster units, and the wheel has a water flow formed by the suction duct and the thruster unit. An underwater moving device, characterized in that it is arranged outside the water. The underwater mobile device according to claim 1,
The underwater moving device characterized in that the suction duct has a cylindrical shape with a rectangular cross section.

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