JPS6228850B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides pretreatment for detecting flaws on the inner surface of a transmission pipe of a heat exchanger, for example, in which a large number of pipes or holes are arranged on one plane, by penetrant testing. The present invention relates to an automatic infiltration device that mechanically applies an infiltration liquid as a process.

Penetrant testing, which detects minute surface flaws without destroying them by soaking a penetrating liquid into the defective area and then allowing it to seep out onto the surface, is used in a wide range of applications because of its simplicity and high detection sensitivity for surface defects. However, this flaw detection method is suitable for manual work and is considered to be one of the fields in which automation is difficult. In particular, the application of penetrant testing from the narrow water chamber formed at the bottom of a vertical steam generator to the inner surface of the heat transfer tube through the tube hole in the tube sheet is done manually, except for a very short area at the entrance. Even then, it was considered impossible. Currently, various methods are used to inspect the health of heat exchangers, but penetrant testing, which can easily detect small defects in any material, is the best method for detecting flaws on the inner surface of tubes such as steam generators. It is desired to make this application possible because of its excellent properties.

The present invention enables automated penetrant testing of tube materials such as heat transfer tubes from inside the water chamber of a heat exchanger, which is difficult or dangerous for workers to access. The purpose is to provide an automatic infiltration device that can be operated remotely. The structure of the present invention that achieves such an object is an apparatus for applying a penetrant liquid for penetrant testing from a water chamber at the bottom of a heat exchanger to the inner surface of a heat exchanger tube, the device being formed on a tube plate and communicating with the heat exchanger tube. A walking robot attached to a tube hole, a swinging arm pivotably attached to the side of the walking robot, a fitting block provided on the swinging arm and having a guide wire connected to its lower end, and the guide wire. a coating unit having a fitting housing that is guided by the fitting block and engages with the fitting block in a detachable manner, and the coating unit is provided with a movable pedestal that is movable up and down with respect to a holding frame fixed to the fitting housing. an infiltration head rotatably protruding from the movable frame; a rotation motor provided within the holding frame for rotating the infiltration head; and a rotation motor connected to the infiltration head to rotate the infiltration head. a permeate supply/discharge device for spouting or suctioning the permeate from the tube plate; and a guide that is attached to the upper end of the holding frame and can be inserted into the tube hole so as to be movable in and out in a direction opposite to the tube plate. It is characterized by

The configuration of the present invention will be explained in detail below based on a specific example shown in the drawings. In this specific example, a vertical thin tube (heat transfer tube) 4 is fixed with a horizontal tube plate 3, and the end portion 2
An example of an apparatus for applying a penetrating liquid to the inner surface of a tube of a steam generator housed in a hemispherical cylindrical shell 1 will be described. In such a steam generator, it is difficult for an operator to enter and work inside the steam generator.

As shown in FIG. 1, this device includes a walking robot 6 that hangs and moves in a tube hole 5, which is a hole to be inspected, a coating unit 8 that applies penetrating liquid into the tube hole 5, and a coating unit 8. It mainly consists of a remote tool exchange device 9 for attaching the tool to the walking robot 6 with one touch.

A walking robot 6 that hangs and moves along the tube plate 3 by using a so-called tube hole 5 in a thin tube 4 fixed to the ceiling tube plate 3 is already known from Japanese Patent Publication No. 17121/1983. ing. Although the walking robot 6 is not shown in detail in the drawings of the present application, the tap shaft that is inserted into the tube hole 5, expands in the radial direction, and comes into close contact with the thin tube 4 can be moved vertically and horizontally within the machine frame. Two carriers each are equipped with two cables that can be moved up and down,
The tap shaft and the carrier are provided so as to move along the tube plate 3 like a palm worm by moving the tap shaft and the carrier together so that the tap shaft is alternately removed and inserted into the next tube hole 5. This walking robot 6 has arms 7 at both ends that can rotate 180 degrees. The center of rotation of the arm 7 is located at a distance that is an integral multiple of the capillary pitch from the walking tap axis mentioned above. Then, a tool remote change device 9 is placed at the tip part further away from the turning center by 5 pitches or an integral multiple of 5 pitches.
A coating unit 8 is removably attached via the.

As shown in FIGS. 2a and 2b, the remote exchange device 9 consists of a fitting block 10 formed integrally with the pivot arm 7 and a fitting housing 11 formed integrally with the application unit 8. It is composed of members. One of the fitting blocks 10 is a corner formed integrally with the tip of an arm 7 that pivots around a pivot pin (not shown) of the walking robot 6 fitted into the fitting hole 12 so as to hang from the arm 7. An engaging hook 13 is column-shaped and has a tapered tip to facilitate insertion, and a locking mechanism is formed inside the engaging hook 13.
and a piston 14 for actuating the hook 13 are built in. The piston 14 engages a half-moon-shaped engagement hook 13 that rotates around a pin 15 on the engagement block 10.
It has a protrusion 16 that engages with the recess 16 of the engagement hook 13, and a spring 17 between the rod part and the bottom of the engagement block 10. It is provided so that the engaging hook 13 is always projected with the intervening. Further, the cylinder chamber housing the piston 14 is provided with a locking port 18 and a releasing port 19, and the engagement between the two can be arbitrarily released by introducing working fluid into the port 18 or 19. or securely secure the two. On the other hand, a fitting housing 11, which is a cylindrical object with a rectangular hole shape in cross section, corresponding to the fitting block 10 is fixed to a holding frame 20 on the coating unit 8 side, and the fitting surface of the fitting housing 11 is fixed to the holding frame 20 on the coating unit 8 side. A coupling groove 21 into which the hook 13 engages is formed. Therefore, the mating housing 11
When it is fitted into the fitting block 10, the engagement hook 13 automatically engages the coupling groove 21 to couple the walking robot 6 and the coating unit 8. Furthermore, when the piston 14 is pushed up by introducing working fluid, The fixed relationship is said to be strong. On the other hand, piston 14
When the engaging hook 13 is pressed down, the engaging hook 13 is attached to the fitting block 1.
Since it is immersed in 0, these connection relationships are easily released.

The coating unit 8, as shown in FIG.
The penetration head 22 inserted into the tube hole 5 which is the hole to be inspected, the drive mechanism that moves the penetration head 22 up and down and rotates, the liquid receiving member that collects excess penetration liquid, the holding frame 20 that supports these, etc. Consists of.

As shown in FIGS. 4 and 5, the permeation head 22 is a rod-shaped member with a sponge 23 attached to the head, and a permeate supply hole 24 communicating with the sponge 23 is formed inside the head from the base end to the head. It is perforated throughout. The sponge 23 is made slightly larger than the tube hole 5, and the sponge 23 is made slightly larger than the tube hole 5.
The outer periphery of No. 3 is provided so as to uniformly contact the inner surface of the tube. The sponge 24 is sandwiched between two flanges 25 that are screwed into the penetration head 22, and then further tightened and fixed with a nut 26. The infiltration head 22 configured as described above is rotatably supported by a movable pedestal 29 that is vertically movably supported by a ball screw 27 and a spline shaft 28 that are rotatably installed in the holding frame 20. installed. A ball nut (not shown) that engages with the ball screw 27 is fixed to the movable frame 29, and a spline nut 30 that engages with the spline shaft 28 is rotatably attached.
Therefore, when the rotation of the lifting motor 33 is transmitted to the ball screw 27 via the gears 31 and 32, the movable frame 29 is moved to the limit switch 3 at the upper and lower ends.
4, 35, that is, within this range, and when the rotation of the rotation motor 36 is transmitted to the spline shaft 28 via the swing gears 37, 38, The permeation head 22 is rotated. That is, the penetration head 22
is raised and lowered and rotated by the drive of both motors 33 and 36. The amount of elevation is determined by detecting the number of revolutions of a magnet 41 at the lower end of the ball screw 27 with a magnetic sensor 42, and the amount of rotation is determined by a potentiometer 43 connected to the spline shaft 28.
Incidentally, the rotation of the infiltration head (less than one revolution) is caused by one 3 of the rocking gears on the spline shaft 28.
9 is fitted so as to be movable together with the movable frame 29, so that the permeation head 22 can be rotated and applied evenly regardless of the position at which the permeation head 22 is extended.
It is also possible to use ordinary disk-shaped gears instead of the swing gears 37, 38, 39, and 40 to rotate the infiltration head 22 by one rotation or more (1/4 rotation or more in the embodiment). In such cases, care must be taken to ensure that the connecting nipple 45 does not twist the connection between the permeate head 22 and the permeate supply tube 44.

In addition, a nipple 4 is provided at the base end of the penetration head 22.
A permeate supply tube 44 is connected through the permeate tube 5, and a liquid reservoir block 46 like a moat surrounding the outer periphery of the permeate head 22 is provided to which a collection tube 47 is connected. The liquid reservoir block 46 is
Seal cover 4 provided above as a liquid receiving member
This is to collect surplus permeate that cannot be collected even through the seal ring 49 of No. 8 and that travels through the permeate head 22. The seal cover 48 above the liquid reservoir block 46 is housed in a cylindrical seal holder 50 formed at the upper part of the holding frame 20 so as to be movable up and down. The seal cover 48 is for receiving the excess permeate dripping down through the tube hole 5 and the permeation head 22 and collecting it by suction through the collection tube connected to the bottom, and is arranged concentrically with the permeation head 22. It is said to be circular. Seal rings 49 and 52 made of porous hygroscopic felt are provided at the opening periphery of the tube hole 5 and at the contact portion with the permeation head 22, respectively, and excess permeate is collected into the collection tube 51 via the suction hole 53. These devices collectively constitute a permeate supply and discharge device. Further, a spring 54 is interposed between the seal holder 50 and the seal cover 48,
A seal ring 52 of the seal cover 48 is provided so as to be elastically pressed against the opening periphery of the tube hole 5. This is to improve the degree of adhesion to the periphery of the opening together with the elasticity of the seal ring 52 itself, and also to make it retract into the seal holder 50 together with the descending penetration head 22 and retreat from the tube plate 3 etc. This is to enable movement to the hole to be inspected.

A guide 55 is provided at the upper part of the holding frame 20 for positioning the permeation head 22, seal ring 52, etc. directly below a predetermined tube hole 5. The inside of the guide 55 is cylindrical, and the pressure of compressed air introduced from the air pressure hole 56 causes a return spring 59 between the guide 55 and the stopper 58 of the holding shaft 57.
It overcomes this and is pushed up and enters the tube hole 5. When the compressed air is cut off, the guide 55 is pulled out of the tube hole 5 by the force of the return spring 59, allowing movement to the next tube hole.

In order to conduct penetrant testing of the thin tube of a steam generator as shown in Fig. 1, using the automatic penetrant device of this specific example, which is configured so that the walking robot 6 side and the coating unit 8 side can be separated in this way. The application of the penetrant to the inner surface of the tube is carried out as follows.

First, the walking robot 6 is installed in a room in advance using the tube hole 5 of the thin tube 4 fixed to the tube plate 3, and the guide wire 60 is hung from the fitting block 10. After passing the guide wire 60 into the fitting housing 11 of the coating unit 8, the coating unit 8 is installed at the tip of the guide jig 61 and inserted into the room through the manhole 62. Guide wire 6
0 guides the coating unit 8 under the fitting block 10 on the walking robot 6 side, so push it in as it is to connect the fitting block 10 (walking robot 6) and the fitting housing 11 (coating unit 8). . Fitting block 10 and fitting housing 11
The fitting is carried out by compressing the spring 17 and pushing the engaging hook 13 protruding from the fitting block 10 into the fitting block 10, so that the fitting is completed and the fitting housing 11 is connected. The groove 21 matches the engagement hook 13 and the spring 1 is compressed.
The engaging hook 13 bites into the coupling groove 21 with a force of 7.
In this state, no matter how much the fitting housing 11 is pulled due to the taper effect of the engagement hook 13, the engagement hook 1
3 will cut into the joint even more, so the bond cannot be easily broken. Therefore, further pressure is applied from the locking port 18 of the piston 14 to push up the piston 14 and forcefully press the engagement hook 13 against the fitting housing 11, thereby firmly fixing it without wobbling. On the other hand, when the application unit 8 is to be removed, pressure is applied from the release port 19 to push down the piston 14 and retract the engagement hook 13 into the block.

After installing the coating unit 8 on the walking robot 6,
Compressed air is introduced into the guide 55 from the air pressure hole 56 to raise the guide 55. Tapered guide 5
The tip of the tube hole 5 is inserted into another tube hole 5' adjacent to the tube hole 5 to be inspected, and if there is a positional deviation, the entire rotating arm 7 is moved to correct, so that accurate positioning can be achieved.

After positioning, the elevating motor 33 is driven to rotate the ball screw 27 and the infiltration head 22 supported by the movable frame 29 is raised. This amount of increase can be detected by the magnet 41 and the magnetic sensor 42. When the magnet 41 rotates, the magnetic sensor 42 turns on and off due to its approach and separation.
do. Since the lead of the ball screw 27 is disconnected, the amount of elevation can be detected by counting the number of ON-OFF pulses per revolution of the ball screw 27. Further, since the upper and lower ends of the vertical movement are detected by limit switches 34 and 35, overrun can be prevented. As the permeation head 22 rises, the seal ring 52 of the seal cover 48 is also pushed up by the spring 54, so that it comes into close contact with the opening periphery of the tube hole 5 and is ready for collection of excess permeate. Sponge 23 of penetration head 22 begins to be inserted into tube hole 5
It has already been wetted with the permeate supplied from a metered dose injector (not shown) through the permeate supply tube 44 and permeate supply hole 24 . By inserting the permeation head 22, which contains the permeate and has a sponge 23 on its head that is slightly larger than the tube hole 5, the permeate is applied to the inner surface of the tube. After the infiltrator head 22 reaches the upper end of the application area, the infiltrator head rotates a fraction of a revolution under the drive of the rotation motor 36 and begins to descend. As a result, even if there is a non-contact part, the penetrating liquid can be evenly applied to the pipe wall over the entire required pipe length. The rotation of the infiltration head 22 may be carried out every other stroke, or may be carried out frequently by continuously rotating the rotation motor 36 in forward and backward directions simultaneously with the raising and lowering. This rotation amount (oscillation amount) is determined by the potentiometer 4 connected to the spline shaft 28.
Since the angle is detected at 3, the angle is regulated based on this value. Since the permeation head 22 can be rotated within a certain range, that is, it can be oscillated, the permeate supply tube 44 is connected to the nipple 45 consisting of a fixed seal.
This allows for reliable sealing of the permeate, which is extremely prone to leakage.

Excess permeate remaining after wetting the sponge 23 flows down the tube wall and the permeate head 22. The seal ring 52 of the seal cover 48 is attached to the spring 54 at the end of the tube.
Since the seal ring 52 is pressed by the force of , the excess penetrating liquid that has flowed down the pipe wall is absorbed by the seal ring 52 . Further, the excess permeate that has flowed down from the permeate head 22 is absorbed by the seal ring 49. The absorbed excess penetrating liquid passes through the suction hole 53 and the collection tube 51, and is continuously sucked up and collected by a suction device (not shown). Excess permeate that is not collected by the seal ring 49 is once stored in the liquid storage block 46 and then suctioned and collected through the collection tube 47.

After the infiltration process, the infiltration head 22 is lowered. Lower flange 25 of the head of the descending infiltration head 22
After contacting the seal cover 48, the spring 54 is compressed and the seal cover 48 is also pulled down.
As a result, the seal ring 52 separates from the opening periphery of the tube hole 5 (tube plate 3), and the sponge 23 exits from the tube hole 5. Also, the pressure applied to the guide 55 is released and the other tube hole 5'
The guide 55 fitted into the tube is pushed down by the force of the spring 59 and removed from the tube hole 5'. This allows the infiltration head 22 to be moved toward the next tube hole to be inspected. Movement is performed by the walking robot 6 using the tube hole 5. Then, repeat the above operations.

In this way, according to the automatic infiltration device of the present invention, it is possible to automatically perform infiltration treatment on the inner surface of heat transfer tubes by remote control in the narrow water chamber of a heat exchanger, which has been considered difficult until now. Enables penetrant testing.

[Brief explanation of the drawing]

The drawings relate to the automatic infiltration device of the present invention.
Figure 1 is an explanatory diagram showing the outline of the working condition, Figure 2 a
2 is a perspective view showing the fitting block and the rotating arm with their internal structure seen through, FIG. A perspective view showing the internal structure of the arm; FIG. 4 is a central longitudinal cross-sectional view showing the structure of the penetrating head, liquid receiving member, and guide in the coating state; FIG. 5 is the penetrating head and liquid receiving member during movement. FIG. 4 is a central vertical cross-sectional view showing the relationship between the guide and the guide. In the drawing, 3 is a tube plate, 4 is a thin tube (heat exchanger tube), 5 is a tube hole which is a hole to be inspected, 6 is a walking robot,
7 is an arm, 8 is a coating unit, 9 is a remote tool changer, 10 is a fitting block, 11 is a fitting housing, 13 is an engaging hook, 20 is a holding frame, 22 is a penetration head, 23 is a sponge, 24 is a permeate supply hole,
29 is a moving frame, 44 is a tube for supplying permeate liquid,
46 is a liquid reservoir block, 47 and 51 are collection tubes, 48 is a seal cover, 49 and 52 are seal rings, 50 is a seal holder, 54 is a spring, and 60 is a guide cable.

Claims (1)

[Claims] 1 A device that applies a penetrant liquid for penetrant testing from a water chamber at the bottom of a heat exchanger to the inner surface of a heat transfer tube, which includes a walking robot installed in a tube hole formed in a tube plate and communicating with the heat transfer tube, and a walking robot. A rotating arm pivotally attached to the side of the robot, a fitting block provided on the rotating arm and having a guide wire connected to its lower end, and a fitting block that is guided by the guide wire and attached to and detached from the fitting block. a coating unit having a fitting housing that freely engages with the fitting housing; the coating unit includes a movable pedestal that is movable up and down with respect to a holding frame fixed to the fitting housing; and a movable pedestal that is rotatable with respect to the movable pedestal. a protruding infiltration head; a rotation motor provided within the holding frame for rotating the infiltration head; and an infiltration liquid connected to the infiltration head to jet or suck the infiltration liquid from the infiltration head. An automated system for penetrant flaw detection characterized by comprising a supply/discharge device, and a guide that is attached to the upper end of the holding frame so as to be movable in and out in a direction opposite to the tube plate, and that can be inserted into the tube hole. Infiltration device.