JPH0886774A - Ultrasonic testing device - Google Patents

Abstract

PURPOSE: To miniaturize an inserting probe, a rotating device and a device for moving an ultrasonic probe so as to increase the applicability of ultrasonic testing by providing a signal cable, an inserting rod, a rotary drive means and a movement means. CONSTITUTION: In order to fully cover the testing range of the inner surface of a heat transfer pipe 31, a flaw detecting probe 10 is fed in the direction of the axis of the heat transfer pipe 31 while being rotated by an inserting rod 50 to spirally scan the inside of the pipe for flaw detection. In this case, since a rotary drive can be installed outside the small-diameter pipe having little space, limitations on size are greatly reduced for ease of manufacture. The inserting rod 50 by which the probe 10 is inserted into the inner surface of the small-diameter pipe is made by a flexible tube and retains a signal cable 12 and a water feeding tube 71 on its inner surface. The tubes and the cable are integrated together and rotated to maintain the properties of the testing probe for rotary scanning and for insertion and to secure the corresponding flexibility at any constricted part. Therefore, an effective testing means can be provided for any heat exchanger that cannot be tested.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic flaw detector, which is one of nondestructive inspection techniques, and more particularly, to detect damage by inserting it into a thin tube such as a heat transfer tube of a heat exchanger. The present invention relates to an ultrasonic flaw detection test device for accurately measuring the form and degree of the damage.

[0002]

2. Description of the Related Art A conventional ultrasonic flaw detection test for a thin tube is carried out by inserting a metal insertion rod provided with an ultrasonic flaw detection probe at the tip thereof into a thin tube as disclosed in, for example, JP-A-57-54857. The ultrasonic probe at the tip is directly rotated by an electric motor, or the insertion rod is moved while rotating the ultrasonic reflecting mirror to spirally scan the inner surface of the thin tube. Also,
In Japanese Patent Laid-Open No. 2-80949, a cable is placed in a bendable insertion rod, the insertion probe is rotated by rotating the cable, and the device itself for rotating the insertion probe is moved. Therefore, it has been proposed to move the insertion probe in the axial direction of the capillary.

[0003]

In the above prior art, since the means for moving the insertion probe in the circumferential direction and the axial direction of the thin tube are separately configured, the flaw detection test apparatus itself becomes large and the heat exchanger. It was difficult to apply it to a narrow space such as near the tube sheet of, and the test could be conducted only in a very limited space.

Further, as in Japanese Patent Laid-Open No. 57-54857,
When the ultrasonic flaw detector is rotated by an electric motor or the like, this electric motor must be built in the insertion probe, and there is a concern that the insertion probe itself becomes large and the applicable range is narrowed.

The present invention has been made in view of the above circumstances, and an object thereof is to miniaturize an insertion probe by rotating an ultrasonic flaw detector from the outside of a thin tube through the insertion probe, and An object of the present invention is to provide an ultrasonic flaw detection test apparatus suitable for expanding the application range of ultrasonic flaw detection by downsizing the rotating device and a moving device for moving and scanning the ultrasonic flaw detector in the axial direction of the capillary.

[0006]

To achieve the above object, an ultrasonic flaw detector according to the present invention is an ultrasonic flaw detector which inserts a flaw detection probe having an ultrasonic probe into a thin tube to detect flaws on the inner surface of the thin tube. In an ultrasonic flaw detector, (a) a signal cable having one end connected to the flaw detection probe and transmitting a flaw detection signal obtained from the ultrasonic probe, and a contact medium near the ultrasonic probe. An insertion rod that is inserted into a tube for supplying and that is bendable, and (b) a support member that connects and supports the other end of the insertion rod.
(C) rotation driving means for rotationally driving the supporting member in the circumferential direction of the capillary, and (d) cooperating with the rotation operation of the supporting member by the rotation driving means to move the supporting member in the axial direction of the capillary. And a means for moving back and forth.

Further, an axial tip end portion of the flaw detection probe is formed so as to be expandable and contractible in the radial direction and the axial direction of the thin tube, and contacts the plural points on the inner surface of the thin tube to rotatably support the flaw detection probe. A flaw detection probe supporting means may be provided.

Further, the advancing / retreating means may be composed of a screw portion formed on an outer peripheral portion of the supporting member, and a screw member engaging with the screw portion to support the supporting member.

Furthermore, the flaw detection probe supporting means is
A plurality of pantograph parts having at least one bent portion arranged in the circumferential direction of the thin tube are formed, and a plurality of aligning devices are connected in the axial direction of the thin tube via a spring member, and A structure in which wheel means for contacting the inner surface of the thin tube is provided in the bent portion may be used.

Further, a position detecting means for detecting the position of the ultrasonic probe may be provided based on the amount of movement of the supporting member in the circumferential direction and the axial direction.

[0011]

[Function] The bendable flaw detection probe insertion rod enables the flaw detection probe to be inserted into the heat transfer thin tube while avoiding obstacles close to the heat exchanger tube plate. Allows testing of thin tubes. The method of rotating the flaw detection probe attached to the tip by directly rotating the insertion rod allows the rotation drive device to be installed outside the narrow tube that has only a small space, so the size restriction is greatly eased. And easy to manufacture. Also,
By providing the signal cable and the water supply tube inside the insertion rod, it is possible to prevent the insertion rod from being wound around the insertion rod or being rubbed against the inner surface of the thin tube and being damaged when the insertion rod is rotated.

Further, by providing a flaw detection probe support means at the tip of the flaw detection probe so as to be capable of expanding and contracting in the circumferential direction and the axial direction of the thin tube and for rotatably supporting the flaw detection probe, a plurality of thin tubes having different caliber can be provided. A flaw detection test can be performed. Even if the flaw detection probe is rotated, the rotation axis of the flaw detection probe does not largely change, and the flaw detection test can be stably performed.

By making a part of the flaw detection probe insertion rod into a screw having a spline and pressing a female screw while rotating the spline gear combined with the spline gear, an amount corresponding to the pitch of the screw in the axial direction Can be sent to. With this configuration, it is not necessary to separately configure the devices for rotating and moving the insertion probe, and therefore the device can be downsized. At this time,
A position signal generator that follows the rotation and axial movement of the insertion rod is used to display the current position of the flaw detection probe and is used to evaluate the position of the material flaw detected by the test.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below mainly with reference to FIGS. An embodiment of the present invention relates to an ultrasonic flaw detection probe for performing maintenance inspection of a heat transfer tube of a turbine high pressure feed water heater of a thermal power generation facility, and FIG. 1 shows an ultrasonic flaw detection probe for measuring wall thickness inserted in the heat transfer tube. .

In order to cover the entire flaw detection range on the inner surface of the heat transfer tube, the probe 10 is fed in the axial direction of the heat transfer tube 31 while being rotated by the insertion rod 50, and flaw detection is performed while spirally scanning the inside of the tube.

The structure of the probe 1 will be described.
At the tip of 0, two pantograph-shaped aligning devices 60 with guide rollers 62 are arranged in series, and the pantographs of each aligning device are installed at three places at 120 ° intervals in the circumferential direction. The inner surface of 31 can be evenly contacted. Further, a coil spring 63 is arranged between the two aligning devices 60, the pantograph is spread by the spring force of the coil spring 63, and the guide roller 62 is brought into contact with the inner surface of the heat transfer tube 31 with a uniform pressure. In addition, a coil spring 5 is attached to each pantograph to restore the opened pantograph. With this aligning device 3, one probe can handle heat transfer tubes having different inner diameters of about φ10 to φ20.

A bearing 13 is provided between the centering device 60 and the probe 10 so that the flaw detection probe 10 can rotate without rotating the centering device 60.

The ultrasonic waves emitted from the probe 11 reach the inner surface of the heat transfer tube and propagate to the base material using the water supplied from the water supply tube 71 as a medium (water jet type). Ring-shaped water seals 72 are attached to the front and rear of the probe 11 to prevent the supplied water from flowing out as much as possible.

FIG. 3 shows the system configuration of the heat transfer tube inspection carried out this time. Probe 10 inserted in heat transfer tube 31
Is fixed to another heat transfer tube by a device fixing rod 212, and rotation and feeding operation by the probe driving device 20 are performed by the insertion rod 50.
Transmitted by. The probe driving device 20 is controlled by the controller 15.

The water used as the contact medium is a water tank 45.
The water stored in the pump is sent to the water supply pipe by the pump 44.

The flaw detection signal is sent to the signal cable 1 in the insertion rod 50.
2 through the slip ring 29 and ultrasonic flaw detector 41
Enter and go to the flaw detection screen. Further, the flaw detection result is recorded in the XY recorder 42 and the recorder 43 together with the information on the position of the flaw detection probe 10 obtained from the position signal generators 208 and 209 described later.

FIG. 2 is a detailed view of the probe driving device 20,
The insertion rod 50 is fastened with an insertion rod fastening screw 202 so as to be integrated with the spline shaft 201. The spline shaft 201 has a spline groove and a screw thread formed on the outer periphery thereof, and the spline shaft 201 is rotationally driven by a motor 207 via a gear 204 integrated with a spline hub 203 joined by a key. The screw part has a semi-circular female thread 2
06 is pressed by the spring 205, and when the spline shaft 201 rotates, the female screw serves to axially send out the spline shaft and the insertion rod clamped thereto.

Reference numeral 208 is a position signal generator for measuring the axial feed amount of the insertion rod, and 209 is a position signal generator for measuring the rotation angle. Reference numeral 210 is a slip ring for extracting the signal from the flaw detection probe 10 to the outside. 212
Is a device fixing rod for fixing the probe driving device main body to the tube plate surface using a thin tube.

The superior characteristics of the ultrasonic flaw detector testing apparatus constructed as above will be described below.

FIG. 5 shows a situation in which this apparatus is applied to a test of a thin tube of a heat exchanger having a water chamber 33. In the test of such a thin tube, the flaw detection probe 10 is rotated. It is necessary to insert the tubule deep into the inner surface, supply a contact medium such as water necessary for the propagation of ultrasonic waves to that position, and maintain stable connection of signal cables and the like. However, in the past, the inner surface of the thin tube was narrow, and miniaturization was utmost to make it possible to insert the flaw detection probe, and it was extremely difficult to incorporate a rotary drive mechanism into it.

A method of attaching a flaw detection probe to the tip of a metal rod having high rigidity and inserting the flaw detection probe into the thin tube is a heat exchanger having a structure in which the space in front of the tube sheet 34 is narrow as shown in FIG. Was not applicable and the range of application was limited.

According to the present invention, the insertion rod 50 for inserting the flaw detection probe 10 into the inner surface of the thin tube is a flexible tube, the signal cable and the water supply tube are housed in the inner tube, and the tube is rotated as a unit. While maintaining the rotational scanning and insertability of the flaw detection probe, it also ensures the flexibility for narrow spaces, and can provide an effective test means for many heat exchangers that were previously impossible to test. It was

In order to make this method effective, the present invention further proposes a device for driving the insertion rod, which has a structure as shown in FIG. 2 for performing rotational scanning of the flaw detection probe and axial feed scanning. It can be done reliably. This device has a feature that it can be applied to heat exchangers of various structures because the mechanism can be installed outside the narrow narrow tube, and as shown in Fig. 5, it can be used by directly attaching it to the tube plate surface. However, it can also be installed outside the water chamber for use.

[0029]

EFFECTS OF THE INVENTION By constructing the insertion type ultrasonic flaw detection probe and the probe driving apparatus as in the present invention, it is possible to downsize the ultrasonic flaw detection test apparatus, and heat which has been difficult to apply conventionally. The ultrasonic flaw detection test of the thin tube of the exchanger can be easily carried out.

[Brief description of drawings]

FIG. 1 is a side view of an insertion type ultrasonic flaw detection probe according to an embodiment of the present invention.

FIG. 2 is a sectional view of a probe driving device.

FIG. 3 is an overall configuration diagram of a capillary ultrasonic testing device.

FIG. 4 is a sectional view of a spline shaft.

FIG. 5 is a configuration diagram when the present invention is applied to a heat exchanger.

[Explanation of symbols]

10 ... flaw detection probe, 11 ... ultrasonic probe, 12 ... signal cable, 13 ... bearing, 20 ... probe drive device, 30 ... heat exchanger, 31 ... heat transfer tube, 41 ... ultrasonic flaw detector, 50 ... insertion rod , 60 ... Aligning device, 61, 63 ... Coil spring, 62 ... Guide roller, 70 ... Contact medium, 71 ...
Water supply tube, 72 ... Water seal, 201 ... Spline shaft, 202 ... Insert rod tightening screw, 203 ... Spline hub, 204 ... Gear, 205 ... Spring, 206 ... Semicircle internal thread, 207 ... Motor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuaki Shiraishi 3-1-1, Sachimachi, Hitachi, Ibaraki Hitachi Ltd. Hitachi factory (72) Inventor, Youji Yoshida 3-chome, Hitachi, Hitachi, Ibaraki 2-1 Hitachi Engineering Co., Ltd.

Claims (5)

[Claims] 1. An ultrasonic flaw-detection test apparatus for flaw-detecting the inner surface of a thin tube by inserting a flaw-detection probe having an ultrasonic probe inside a thin tube, wherein (a) one end is connected to the flaw-finding probe, A signal cable for transmitting a flaw detection signal obtained from the ultrasonic probe, and a tube for supplying a contact medium in the vicinity of the ultrasonic probe, and an insertion rod formed to be bendable, (b) ) A supporting member that connects and supports the other end of the insertion rod, (c) a rotation driving unit that rotationally drives the supporting member in the circumferential direction of the capillary, and (d) the support by the rotation driving unit. An ultrasonic flaw detection test apparatus comprising: an advancing / retreating means for advancing / retreating the support member in the axial direction of the thin tube in cooperation with the rotational movement of the member. 2. The ultrasonic flaw detection test apparatus according to claim 1, wherein an axial tip end portion of the flaw detection probe is formed so as to be expandable and contractible in a radial direction and an axial direction of the thin tube, and at a plurality of positions on an inner surface of the thin tube. An ultrasonic flaw detection test apparatus comprising: flaw detection probe support means for rotatably supporting the flaw detection probe in contact with the flaw detection probe. 3. The ultrasonic flaw detection test apparatus according to claim 1, wherein the advancing / retreating means supports a threaded portion formed on an outer peripheral portion of the support member and the threaded portion to support the support member. An ultrasonic flaw detection test apparatus, comprising: 4. The ultrasonic flaw detector test apparatus according to claim 2, wherein the flaw detection probe support means is formed by arranging a plurality of pantograph portions having at least one bent portion in a circumferential direction of the thin tube. Ultrasonic flaw detection, characterized in that a plurality of aligning devices are connected in the axial direction of the thin tube via a spring member, and wheel means for contacting the inner surface of the thin tube is provided at the bent portion. Test equipment. 5. The ultrasonic flaw detector test apparatus according to claim 1, further comprising position detecting means for detecting the position of said ultrasonic probe based on the amount of movement of said support member in the circumferential and axial directions. Ultrasonic flaw testing equipment characterized in that