JPS634664B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a tube inspection device suitable for detecting damage to tubes having complex shapes such as multilayer helical coil heat transfer tubes for nuclear reactors.

Once the heat exchanger tubes installed in the heat exchanger of a nuclear reactor are damaged, a major disaster may occur, so they must be inspected periodically. However, heat exchanger tubes have a complicated shape due to the need to increase heat transfer efficiency, and the total length of the heat exchanger tubes themselves is quite long, and there is a considerable amount of residual radioactivity in the vicinity of the heat exchanger even after the reactor operation is stopped. This makes it impossible to work for long periods of time, making flaw detection work on pipe bodies difficult. For this reason, a tube inspection device as shown in FIG. 1 was provided.

In the figure, the cable 2 of the inspection device 1 is connected to the water chamber 3.
After wrapping around the drum 4a placed in the interior of the drum 4a several times, it passes through the rotating shaft 5a and reaches the inside of the tube to be inspected. A sensor 6 is attached to the tip of the cable 2 for inspecting the tube body. Pressurized water W is supplied to the water chamber 3a, and this pressurized water W reaches the tube body to be inspected from the cable feed-out hole 7 formed in the drum 4 through the rotating shaft 5a, and the sensor 6 advances inside the tube body by the flow of this pressurized water. do. Reference numeral 8a is a handle for controlling the rotation of the drum 4a, and the moving speed of the sensor 6 is adjusted by controlling the rotational speed of the drum 4a. However, in this device, since the cable 2 is first let out from the rotating shaft of the drum 4a, the cable becomes twisted as the drum rotates, and the sensor 6 rotates within the tube, making accurate inspection difficult. Further, since the cable 2 connected to the inspection device 1 disposed outside the water chamber 3a is introduced into the water chamber 3a, it is difficult to seal the cable introduction port 9, and there is a problem of water leakage. In particular, since pressurized water W must be supplied to the water chamber 3a at a considerably high pressure in order to move the sensor 6, sealing the cable inlet 9 becomes even more difficult.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems and provide a tube inspection device in which a sensor can be easily fed out and leakage of pressurized water does not occur.

In short, this invention involves attaching a large number of floats to a cable with a sensor attached to its tip, winding the cable with the floats in advance for the distance the sensor moves, and letting out the cable in a direction perpendicular to the axis of rotation of the drum to prevent twisting of the cable. prevent,
Furthermore, a small-diameter drum is installed coaxially with this drum, and the indoor cable connected to the above-mentioned cable is wound around it.By winding and unwinding the indoor cable, the cable does not have to pass through the wall of the water chamber and move, thereby improving waterproofness. It is designed to be almost complete.

Embodiments of the invention will be described below with reference to the drawings.

In FIG. 2, floats 11 are attached to a cable 2 having a sensor 6 at its tip at approximately equal intervals, thereby preventing the cable 2 itself from coming into contact with the inner wall of the tube body 10 and reducing detection accuracy. At the same time, the sensor 6 is configured to move favorably in response to the flow of pressurized water W.

FIGS. 3 to 5 show an apparatus for feeding out the cable 2 constructed as described above (hereinafter referred to as "cable with float").

First of all, in FIGS. 3 and 4, 4 is a drum for feeding out the cable 2 with a float, and the cable 2 has a length sufficient for moving the sensor 6 in advance.
It is wrapped around. 12 is a small diameter drum attached to the rotating shaft 5, and the cable 2 with the float and the rotating shaft 5 are connected to each other.
An indoor cable (no float attached) 13 is wound in the same direction as the cable 2 with a float. Reference numeral 14 denotes a sealing material provided at a portion where the indoor cable 13 passes through the wall surface of the water chamber 3, but since the indoor cable 13 does not move through this wall surface, the sealing can be performed completely. Further, reference numeral 15 is a counter attached to one end of the rotating shaft 5, which detects the number of rotations of the drum 4 and confirms the moving distance of the sensor 6.
8 is a handle for adjusting the rotation speed of the drum 4.

In the apparatus described above, the cable 2 with a float wound around the drum 4 moves and flows out from the cable feeding pipe 16 arranged almost perpendicular to the rotation axis 5 due to the outflow force of the pressurized water W, and is transferred to the pipe body to be inspected. flows in and moves within this tube. In this case, the cable 2 with a float is let out in the direction of rotation of the drum 4, so no twisting occurs. As the cable 2 is fed out, the indoor cable 13 that has been wound around the small diameter drum 12 is also gradually fed out from the rolled-up state as shown at 13' and bent at the bottom of the water chamber 3 as shown in the figure. When the cable with float 2 is further fed out with all the indoor cables 13 being fed out, the indoor cable 13 bent at the bottom of the water chamber 3 is
As shown in the figure, it is instead rolled up into the small diameter drum 12. In other words, the rotation of the drum 4 can be ensured until all the indoor cables wound around the small diameter drum 12 are paid out and this cable 13 is completely wound up. Here, the drum 4 and the small-diameter drum 12 are attached to the same shaft and rotate in the same manner, so that the amount of cable that is fed out from each drum is proportional to the radius of each drum.
The radius of the drum 4 is R, and the radius of the small diameter drum 12 is r.
If the length of the cable 2 with a float wrapped around the drum 4 is L, each drum will be approximately L/2πR (where π is the circumference) while the cable 2 with a float is completely unwound.
It will rotate. In this case, assuming that the indoor cable 13 of the small-diameter drum 12 is also only fed out like the cable 2, the length of the indoor cable 13 is determined by the following equation (1).

2πr×L/2πR=Lr/R (1) However, since the indoor cable 13 is unwound and unwound while the entire cable 2 is unwound, the actual length is half of Lr/R calculated using the above formula (1). It becomes Lr/2R.

For example, if the radius of the small-diameter drum 12 is 1/4 of the drum 4, the length of the indoor cable 13 will be about 1/8 of the cable 2, and if the radius is 1/5, then the length of the indoor cable 13 will be about 1/10.

The sensor 6 is moved by the handle 8 on the drum 4.
This is done by controlling the rotation of the Further, the moving distance of the sensor 6 is detected by a counter 15.
Information sent from the sensor 6 is sent to the float cable 13
The data is then input to the inspection device 1 via the outdoor cable 20 and analyzed.

When the inspection of the pipe body is completed by the above method, the supply of pressurized water W is stopped, and the cable with float 2 is rewound using the handle 8. Along with this, the indoor cable 13 is also once unwound from the small-diameter drum 12, and then wound in the same direction as the winding direction of the cable 2, making it ready for the next inspection.

By carrying out this invention, the cable is fed out in the direction of rotation of the drum, so that twisting of the cable does not occur.

In addition, since the cable that passes through the wall of the water chamber does not pass through the wall and move, various effects such as easy sealing of pressurized water and no fear of water leakage are achieved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a conventional feeding device viewed from above, Fig. 2 is a partially cutaway view of a tube body showing a cable with a float according to the present invention, and Figs. A sectional view of the device, FIG. 4 is a sectional view taken along line AA in FIG. 3. 1... Inspection device, 2... Cable with float, 3...
...Water chamber, 4...Drum, 5...Rotating shaft, 6...Sensor, 11...Float, 12...Small diameter drum, 13
...Indoor cable, 15...Counter.

Claims (1)

[Claims] 1. Consists of a float-equipped cable having a sensor at its tip and a large number of floats attached, and a device for feeding out the float-equipped cable, and the device for feeding out the float-equipped cable has a water chamber containing pressurized water. a drum disposed within the water chamber and feeding out the cable with a float in its own rotational direction; a small diameter drum attached to the same rotating shaft as this drum; and a drum connected to the cable with the float and wound around the small diameter drum. A pipe body inspection device comprising an indoor cable, and the indoor cable is connected to an inspection device via an outdoor cable. 2 The winding direction of the indoor cable into the small diameter drum is the same as the winding direction of the float-equipped cable into the drum, and the indoor cable is let out and rolled in corresponding to the let-out distance of the float-equipped cable. The tube inspection device according to scope 1. 3. The tube inspection device according to claim 1 or 2, characterized in that a counter is attached to the rotating shaft.