JPS6228858B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for automatic penetrant testing of the inner surface of a tube used for penetrant testing of steam generators and the like.

Penetrant testing has been applied to testing various structures because of its simplicity and high sensitivity for detecting defects on the surface to be tested. However, this flaw detection method is based on manual flaw detection, and there are many technical problems when automating it. In particular, with regard to flaw detection inspection inside pipes such as steam generators, there has been a problem in that even manual flaw detection cannot be performed satisfactorily except in extremely narrow areas at the entrance.

The present invention has been made in view of the above, and provides a developing device for automatic penetrant inspection of the inner surface of a tube, which can remotely control and automate penetrant inspection of a desired portion inside a pipe such as a steam generator. be.

That is, the present invention detects flaws on the inner surface of heat transfer tubes that are attached to the lower water chamber tube plate of a rigid heat exchanger, and includes a walking robot that is attached to the tube plate, and a robot that is pivotally attached to the side of the walking robot. a fitting block attached to the lower surface of the arm and to which an inner end of a guide wire is connected; and a penetrating developing device guided by the guide wire and detachably fixed to the fitting block; A holding frame fixed to the joint block, a movable stand provided within the holding frame so as to be able to rise and fall freely, a rotating shaft rotatably erected on the moving stand and mechanically connected to the rotating motor, and the same rotating shaft. Automatic penetrant flaw detection on the inner surface of a tube, characterized in that the penetrant developing device is constituted by a mist guide tube that is inserted into the tube and has a developing head at its protruding tip, and a developer supply and discharge device connected to the mist guide tube. This is a developing device for

Examples of the present invention will be described below.

FIG. 1 is a sectional view of an embodiment in which a developing device for automatic penetrant flaw detection on the inner surface of a tube according to the present invention is applied to penetrant flaw detection on the inner surface of a thin tube of a steam generator. In the figure, 1 is a cylindrical shell forming a steam generator, and the lower part of the cylindrical shell 1 is a hemispherical water chamber 2. Water chamber 2
is separated by a tube plate 3 and a partition wall. The tube plate 3 is provided with a group of thin tubes 4. Heated pressurized water flows inside the tube. This developing device 13 for automatic penetrant inspection on the inner surface of a tube is constructed by inserting two pairs of four tap shafts into the thin tube holes 10 of the tube sheet 3, fixing them, and suspending them from the tube sheet 3.
It can be freely attached to and detached from the walking robot 11 that freely walks on a surface. The connection between the developing device 13 for automatic penetrant inspection of tube inner surfaces (hereinafter referred to as the developing device) and the walking robot 11 will be described later using the fitting block 56 of the arm 12 provided at both ends of the walking robot 11 so as to be able to rotate freely through 180 degrees. This is done by fitting the fitting housing 101 of the developing device 13. The fitting block 56 and the fitting housing 101 are fitted by attaching the developing device 13 to the tip of the replacement jig 17, inserting it into the interior through the manhole 14 bored in the wall of the water chamber 2, and then fitting the developing device 13 to the tip of the replacement jig 17. This is done using the guide wires 15 and 16 passed through the block 56 as a guide.

As shown in FIGS. 2A and 3B, and 3A and 3B, this developing device 13 has a developing head 405 that is inserted into the thin tube hole 10 of the tube plate 3. There is. The developing head 405 is attached to the tip of a rotating shaft 406 that is moved up and down and rotated by a lifting mechanism and a rotating mechanism that will be described later. As shown in FIGS. 4A and 4B, the developing head 405 has a slit 408 for causing the developing mist to flow out onto the surface to be inspected.
It has a mist guiding pipe 453 in which a plurality of holes are formed. A conical plug 407 is provided at the tip of the mist guiding pipe 453 to adjust the outflow direction of the developing mist. A gap is provided between the mist guiding pipe 453 and the rotating shaft 406, and the suction port 361 is connected to a suction port 361 that suctions the developing mist not attached to the surface to be inspected, and is connected to a suction device described later. A recovery gap 454 is formed.

Rotating shaft 4 with developing head 405 attached to the tip
06 is housed within the holding frame 401. Inside the holding frame 401, an elevating mechanism that moves the rotating shaft 406 up and down and a rotating mechanism that rotates the rotating shaft 406 are provided.

A lifting motor 420 constituting the lifting mechanism is provided at the bottom of the holding frame 401. The lifting motor 420 is connected to a gear 422 via a gear 421. At the center of the gear 422 is a ball screw 4.
23 are erected. A movable pedestal 424 is attached to the ball screw 423 via a ball nut 425, and as the ball screw 423 rotates, the movable pedestal 424 moves up and down.
The movable pedestal 424 holds a rotating shaft 406, and is configured to freely move up and down as the movable pedestal 424 moves. The movable frame 424 has a second
A striker 430 is attached as shown in Figure B. The striker 430 includes an upper end limit switch 428 and a lower end limit switch 42 provided at predetermined positions at the upper and lower ends of the movable frame 424 that move up and down.
9, the movable frame 424
The vertical movement distance is controlled. Furthermore, a rotary plate on which magnets 426 are attached at equal intervals is provided below the gear 422 provided with the ball screw 423. A magnetic sensor 427 is provided opposite this magnet 426.
By the interlocking operation of the magnetic sensor 427 and magnet 426, the aforementioned limit switches 428, 429, and the lifting motor 420, the rotating shaft 406
It is designed to control the vertical movement of the

On the other hand, a rotating motor 440 that constitutes a rotating mechanism
is provided on the upper part of the holding frame 401 as shown in FIGS. 2A, 3A, and 3B. The rotation motor 440 connects to the spline shaft 44 via a gear 441.
3. Spline shaft 443 is connected to gear holder 445 via spline nut 446. The gear holder 445 is rotatably held on the movable frame 424 and meshes with a gear 444 fixed to the rotating shaft 406. The gear 441 connected to the rotation motor 440 is provided with a magnet 448. A magnetic sensor 447 is provided opposite the magnet 448 to control the rotation speed of the rotating shaft 406.

Further, inside the rotating shaft 406, a mist guiding pipe 453 whose tip constitutes the developing head 405 is housed. A collection gap 454 consisting of a gap formed between the mist guide pipe 453 and the rotating shaft 406 has a
A collection chamber 458 is provided by a pair of seals 456 and 457.
is formed. The recovery chamber 458 is connected to a suction tube 460 of a recovery device (not shown) through a small hole 459.
is connected to.

Further, a seal holder 470 is provided via a spring 471 at a portion where the rotating shaft 406 projects outward from the holding frame 401 . Seal holder 470
A lip seal 472 is provided on the upper edge of the tube, and is adapted to come into contact with the tube end of the object to be tested. The seal holder 470 has a holder stopper 47.
3 is provided so that the lower end 415 (head end) of the developing head 405 comes into contact when the rotating shaft 406 is lowered. Seal holder 470
forms a recovery chamber 474 with the holding frame 401, and the recovery chamber 474 communicates with a suction tube 476 via a recovery suction hole 475, and is further connected to a recovery device (not shown).

Further, on the upper outer surface of the holding frame 401 near the seal holder 470, a cylindrical guide 4 is provided in parallel with the rotating shaft 406 projecting to the outside as shown in FIG.
90 is provided protrudingly. The guide 490 has a cylindrical interior and is attached via a return spring 492 to a holding shaft 493 erected on the holding frame 401 . A pneumatic hole 491 is bored in the lower part of the guide 490, so that the guide 490 is pressurized in a direction that overcomes the reaction force of the return spring 492. Note that the return spring 492 is held by a stopper 494 provided on a holding shaft 493.

Further, on the side of the holding frame 401, as shown in FIGS. 2A and 6, there is a fitting housing 101 that fits into a fitting block 56 provided on the walking robot 11 that moves on the surface to be inspected. installed.
The fitting housing 101 has a fitting groove 113 into which a pair of cam-shaped pinions 57 and 58 provided on the fitting block 56 fit.

The fitting block 56 is fixed to the arm 12 attached to the walking robot 11, as shown in FIGS. 6 and 7A to 7C. The piston 51 extends from the tip of the arm 12 to the fitting block 56.
is built-in. The piston 51 is a piston rod 53 supported at one end by a spring 52, and a pair of racks 54, 55 are provided at the center thereof. The fitting block 56 containing the piston rod 53 has a rectangular shape, and its tip is tapered. Cam-shaped pinions 57, 58 are rotatably supported by pins 59, 60 at positions corresponding to the racks 54, 55 of the fitting block 56, and are engaged with the racks 54, 55.

Further, a spray pipe for spraying a developer is attached to the lower end of the rotating shaft 406. The spray tubes are as shown in Figures 8, 9A and 9B.
As shown in the figure, a flexible guide tube 512 is attached to the tip of the cylindrical main body (spray chamber) 511, and a connecting tube 451 is attached to the tip of this guide tube 512, so that the atomization is carried out through the atomizing tube 453 and the developing head 405. Inspection 51
4, a liquid mist of developer is sprayed.
Further, a developer supply pipe 51 is provided at the base end of the cylindrical main body 511.
5. An air supply pipe 516, an air sweep pipe 517 for sending high-pressure air, and a drain pipe 525 are installed.
Furthermore, the developer supply pipe 515 has a switching valve 518.
is installed, and the developer supply pipe 5 is connected to this switching valve 518.
19. A cleaning pipe 520 for sending high-pressure air and a pair of piston operating empty pipes 521a and 521b are attached.

The cylindrical main body 511 is provided with a squeeze tube portion 511a having a gently tapered cross section and a V-shaped cross section at the tip,
A guide tube 512 is attached through the aperture tube portion 511a. Further, a gas-liquid mixing type spray nozzle 522 is built in the cylindrical main body 511, and the developer supply pipe 515 is connected to the spray nozzle 522.
and an air supply pipe 516 are connected. In addition, a liquid drain hole 5 is provided between the spray nozzle 522 and the inner wall of the main body.
23 is formed, and this drain hole 523 is connected to the space 5.
It communicates with a drain pipe 525 via 24. Further, the air sweep pipe 517 opens into the space 524 .

Further, the switching valve 518 has a liquid piston 526.
The liquid piston 526 is pressed in the direction of arrow A by a compression coil spring 527, and reciprocated in the direction of arrow A and arrow B by applying pressure from the piston operating hollow tubes 521a and 521b. Further, the switching valve 518 includes a liquid passage 528 communicating with the developer supply pipe 519;
529 is provided, and the liquid passage 529 communicates with a valve seat 531 through a small hole 530 provided at the tip of the liquid piston 526, and further communicates with a liquid reservoir 532 and the developer supply pipe 515. The liquid reservoir 53
A pouch valve 534 which is normally closed by a compression coil spring 533 is attached to the pouch valve 2, and the liquid reservoir 532 is communicated with the cleaning pipe 520 by opening the pouch valve 534. Note that 535 in the figure is a seal.

Using the developing device 13 configured in this manner, penetrant flaw detection of a steam generating device can be performed as shown in FIG.

First, the developing device 13 is attached to the walking robot 11 movably attached to the thin tube group 4 of the tube plate 3, which is the object to be inspected, in the following manner. The developing device 13 is attached to the tip of the replacement jig 17, and this is inserted into the steam generator through the manhole 14. Next, this is guided directly under the fitting block 56 of the walking robot 11 using the guide wire 16 passed through the fitting housing 101 as a guide. When the replacement jig 17 is pushed up in this state, the fitting housing 101 is fitted into the fitting block 56. At this time, the gum-like pinions 57 and 58 are rotated in the _B1 direction by the force in the _A1 direction shown in FIG. . Therefore, as the fitting progresses further, the fitting housing 101 that has overcome the spring force will move toward the cam-shaped pinion 5.
7, 58 inward, and the cam-shaped pinion 5
The tips of 7 and 58 are inserted while sliding on the fitting surface 112. Since a fitting groove 113 is formed in the fitting surface 112, the spring 52 pushes back the piston rod 53, and the cam-shaped pinions 57 and 58 move into the fitting groove 1.
It meshes with 13. In this way, the developing device 13 can be reliably attached to the walking robot 11 through extremely simple operations. Furthermore, the piston 51 of the fitting block 56
When pressure is applied to the lock side of the cam-shaped pinion 57,
58 completely fits into the fitting groove 113, and the fitting housing 101 is sufficiently fixed.

Note that when the developing device 13 is removed from the walking robot 11, pressure is applied through the release side air supply hole 62 of the piston 51. Due to this pressurization, the piston 51 and the piston rod 53 move in the _A2 direction as shown in FIG.
B Rotate in _two directions. As a result, the tips of the cam-shaped pinions 57 and 58 are accommodated in the fitting block 56, the action of the fitting groove 113 is released, the fitting housing 101 and the fitting block 56 slide freely, and the developing device 13 can be easily removed from the walking robot 11.

As described above, the developing device 13 can be attached to and detached from the walking robot 11 by an extremely simple operation, and the walking robot 11 can be moved to a desired point by remote control to smoothly conduct penetrant testing at a predetermined location. I can do it.

The developing device is attached to the walking robot 11 as described above.
13 is attached, the test surface 5 is attached as follows.
14, a developer mist is applied. In other words, the rotation axis 1
The developing mist flowing through the mist guiding pipe 453 of No. 06 changes its flow path by the conical plug 407, passes through the slit 408, and obliquely hits and adheres to the wall surface. At this time,
The flow path of the developing mist changes depending on the taper of the conical plug 407, but by selecting it appropriately, it can be made to adhere only to the wall surface without being attached to the plug 407. In addition, in this state, the recovery gap 454
When more suction is performed, a flow occurs in the X direction as shown in FIG. 4B, and the developer is suctioned and collected from the suction port 367 into the collection gap 454. Therefore, the developing mist hits the wall surface at a substantially right angle due to the addition of a flow path near the wall surface, further improving adhesion. Also,
When the rotating shaft 406 is rotated, the adhesion state becomes extremely uniform, and by moving the rotating shaft 406 up and down, development can be easily performed at a predetermined position.

In addition, the development head 405 during penetrant testing
The lifting and lowering operations are performed as follows.

First, when the lifting motor 420 is driven, its rotational force is transmitted to the ball screw 423 via the gears 421 and 422, and the movable frame 424 is moved up and down by the action of the ball nut 425. As the movable frame 424 moves up and down, the rotating shaft 406 moves up and down, and the developing head 4 moves up and down.
05 goes up and down.

At this time, the magnet 426 is connected to the magnetic sensor 427.
An ON-OFF pulse is generated in the magnetic sensor 427 by the approach and separation due to the rotational force of the magnetic sensor 427. The number of pulses is generated in accordance with the number of magnets 426 that appear when the ball screw 423 rotates once, so by knowing the lead of the ball screw 423, the position of the movable frame 424 can be calculated. As a result, the processing position of the developing head 405 can be detected, and flaw detection processing can be performed on a desired pipe length with high positional accuracy.

In addition, the development head 405 during penetrant testing
The lifting and lowering operations are performed as follows.

First, when the rotation motor 440 is driven, its rotational force is transferred to the gears 441, 442 and the spline 44.
3. Spline nut 446, gear holder 44
5, gear 444, and rotating shaft 406.

At this time, the rotation shaft 406 is installed on the movable frame 424, but can be driven by a fixed rotation motor 440 due to spline action.

The magnet 448 and the magnetic sensor 447 generate ON-OFF pulses depending on their proximity and separation. Since the reduction ratio between each gear is known in advance, the amount of rotation can be determined by counting these ON-OFF pulses. Further, the rotation speed can also be determined from the pulse speed, and it can be determined whether the developing head 405 is rotating at an appropriate speed.

Furthermore, the supply and recovery of the developer during penetrant flaw detection is performed as follows.

The developer supplied from the switching valve 518 is atomized by the spray pipe (cylindrical main body 511, tapered pipe 511a) and reaches the guide pipe 512. After that, connecting pipe 4
51, through the mist guide pipe 453, and the slit 408,
Stick to the wall. The unattached mist is collected through the suction port 361, the collection gap 454, the small hole 459, the collection chamber 458, and the suction tube 460 in this order.

Further, at this time, the seal holder 470 is also suctioned, and the developing mist that cannot be collected from the suction port 361 is collected into the collection device through the collection chamber 474, the collection suction hole 475, and the suction tube 476 in this order.

As a result of the above, the non-adherent developing powder is completely recovered.
Development processing can be performed without contaminating the atmosphere of the object to be inspected.

Further, the guide 490 provided at the upper part of the holding frame 401 operates as follows.

When air pressure is applied to the air pressure hole 491, the guide 4
90 overcomes the return spring 492 and rises. Since the tip of the guide 490 is tapered,
It is quickly inserted into a tube adjacent to the tube to be processed, and if there is a positional shift in the developing device 13 or the like, it is corrected, so that the developing head 405 can be accurately positioned. Further, when the pressure in the air pressure hole 491 is released, the guide 490 is pushed down by the reaction force of the return spring 492, and the guide 490 is separated from the adjacent pipe, allowing the developing head 405 to be moved to another position.

Next, the function of the spray chamber will be explained.

First, during development, when pressure is applied to the opening piston working space 521a, the liquid piston 526 moves in the direction of arrow B, the valve seat 531 opens, and the developing liquid flows from the liquid passages 528, 529 to the valve seat 531 to the liquid reservoir. 5
32→Developer solution passes through the developer supply pipe 515 and is supplied to the spray nozzle 522. On the other hand, air is supplied from the air supply pipe 516 to the spray nozzle 522 . The developer and air thus supplied are mixed and sprayed to form a liquid mist. When this liquid mist hits the inner wall of the main body 511, as shown in FIG. 8, most of it is liquefied again and flows down the inner wall, passes through the drain hole 523 and the space 524, and is discharged from the drain pipe 525. In this case, coarse particles tend to be more easily liquefied, and the coarse particles and fine particles in the liquid mist are separated here. Further, since the recondensed liquid can be accumulated in the space 524, the tip of the spray nozzle 522 is prevented from becoming below the liquid level.

Next, the liquid mist that did not hit the inner wall of the main body 511,
The liquid mist made up of relatively fine particles that did not liquefy even after the collision is guided to the guide tube 512, repeatedly collides with the inner wall and leaves, and a portion of it is liquefied and passes through the tube wall and enters the main body. 511 and is discharged from drain pipe 525. Even in this case, since coarser particles tend to liquefy more easily, only ultrafine particles remain until they reach the developing head 405, and a uniform fine liquid mist is sprayed from the tip.

In this way, a uniform fine liquid mist is sprayed,
High-sensitivity development is possible without particularly setting the distance to the test surface 514.

Next, when the development is completed, pressure is applied from the closing piston operating space 521b to move the liquid piston 526 in the direction of arrow A, and close the valve seat 531.
Stop the developer supply.

Next, when high-pressure air or liquid is supplied to the cleaning pipe 520, the poppet valve 534 opens against the spring force, and the high-pressure air instantly removes the developer accumulated in the liquid reservoir 532, developer supply pipe 515, and spray nozzle 522. to prevent the developer from sticking.

Furthermore, when high-pressure air is supplied to the air sweep pipe 517, the developing solution adhering to the inner wall of the main body 511 is peeled off and separated, thereby preventing the passage from being narrowed due to adhesion of the adhering liquid. Therefore, since the developer can be removed satisfactorily, development can be carried out continuously.

In addition, these operations are performed using the developer supply pipe 515, the air supply pipe 516, and the piston operation empty pipes 521a and 52.
1b, the cleaning pipe 520, and the air sweep pipe 517, so remote automatic operation is possible.

As explained above, the developing device for automatic penetrant flaw detection on the inner surface of a tube according to the present invention has a developing head provided at one end of the rotary shaft that rotates and moves up and down, a spray chamber connected to the other end, and Since it can be easily attached to and detached from a walking robot that moves freely over the surface, it is possible to perform penetrant testing of a desired part of the pipe, which is the object to be inspected, by remote control and automation, which improves work efficiency and safety. It has remarkable effects, such as being extremely excellent.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment in which the developing device for automatic penetrant flaw detection on the inner surface of a tube according to the present invention is applied to penetrant flaw detection in a thin tube of a steam generator. A perspective view of a developing device for penetrant flaw detection, Figure B
is an enlarged view of the limit switch of the same device, Figure 3A
is a side view of the developing device, FIG. 4B is a front view of the same developing device, FIGS. An enlarged view, FIG. 6 is an explanatory view showing the fitting block of the walking robot fitted into the fitting housing of the developing device, and FIG. 7A is a perspective view of the fitting block shown in FIG. 6. Figure B is an enlarged view of the piston part of the fitting block, Figure C is an enlarged view of the cam-shaped pinion of the fitting block, and Figure 8 is a sectional view of the spray chamber provided in the developing device. , FIGS. 9A and 9B are fragmentary side views of essential parts of the spray chamber shown in FIG. 8. DESCRIPTION OF SYMBOLS 11...Walking robot, 13...Developing device for automatic penetrant inspection of tube inner surface, 56...fitting block, 101...fitting housing, 405...developing head, 406...rotating shaft, 511...cylindrical body (spray chamber), 522...
Spray nozzle,...lifting mechanism,...rotating mechanism.

Claims (1)

[Claims] 1. A device that is attached to the lower water chamber tube plate of a rigid heat exchanger to detect defects on the inner surface of the heat transfer tube, and includes a walking robot that is attached to the tube plate, an arm that is pivotally attached to the side of the walking robot, and the arm. a fitting block attached to the lower surface of the guide wire and connected to the inner end of the guide wire; and a penetrating development device guided by the guide wire and detachably fixed to the fitting block, the device being fixed to the fitting block. a holding frame, a movable stand provided within the holding frame so that it can be raised and lowered, a rotating shaft that is rotatably erected on the moving stand and mechanically connected to the rotating motor, and a rotating shaft that is inserted through the rotating shaft and protrudes. A developing device for automatic penetrant flaw detection on the inner surface of a tube, characterized in that the penetrating developing device is constituted by a misting tube having a developing head at its tip and a developer supply/discharge device connected to the misting tube.