JPH0737965B2 - Pipe insertion type ultrasonic flaw detection probe - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a probe having a structure for performing ultrasonic flaw detection while being inserted into a pipe to be inspected and being swept away by fluid pressure.

[Conventional technology]

In the conventional flaw detection probe, as described in JP-A-56-49957, an appropriate number of blade aligning tools are attached to the probe body, and the probe body is driven by using fluid pressure.

FIG. 3 (A) shows an example of a conventional tube-insertion type ultrasonic probe. A plurality of aligning tools 12 with blades are attached to a contactor body 2 having a wave transmitter / receiver 8 for transmitting / receiving an ultrasonic beam and a rotary scanning mechanism unit 14 for rotating / scanning the ultrasonic beam.
The fluid pressure of the fluid 9 flowing in the heat transfer tube 1 is adjusted by the blade aligning tool 12
The pressure is applied to drive the probe individual body 2 inserted into the heat transfer tube 1 in the traveling direction of the fluid 9.

FIG. 3B is an end view of the winged aligning tool 12, and FIG.
Is a sectional side view of the same. Since the probe main body 2 is always held concentrically with respect to the central axis of the heat transfer tube 1 by the bladed centering tool 12, even if the tube inner diameter of the heat transfer tube 1 changes, the probe main body 2 is based on a stable condition. Ultrasonic flaw detection can be performed.

[Problems to be solved by the invention]

The above-mentioned known technology does not consider the following points, and therefore, it has been feared that the soundness of the heat transfer tube is adversely affected and that the flaw detection signal detected from the probe is affected.

(I) The inner wall of the pipe and the aligning tool with blades are in direct contact with each other, and abrasion and scratches on the inner surface of the pipe are expected.

(Ii) In the prior art, the main body of the flaw detector is always held concentrically with respect to the central axis of the pipe at both ends of an appropriate number of bladed aligners attached to the flaw body. Attention
The member is an elastically deformable member, and the contact with the inner surface of the pipe is line contact (circumferential contact). For this reason, the supporting state is unstable with respect to a tortuous (so-called sheep intestine) tube or a spiral pole tube. As a result, the set angle of the ultrasonic beam may change.

The present invention has been made in view of the above circumstances, it is possible to hold the ultrasonic probe in a correct position for a sheep intestinal tube or a spiral tube, and for changes in the tube inner diameter. It is intended to provide an ultrasonic probe for insertion into a tube, which has a centering function and can be smoothly adapted.

[Means for solving problems]

In order to achieve the above object, the present inventors have focused on the centering mechanism of the probe main body and the contact resistance of the inner wall of the pipe during traveling in the pipe, and on the circumference at appropriate intervals like the conventional centering tool with blades. Instead of adapting to the circumferential contact of an elastically deformable annular member formed by multiple blades arranged in a row, the centering fins can be freely expanded or squeezed in the tube by utilizing the fluid force in the tube. Like 2
By attaching a centering fin having an area capable of being divided and formed into a trap and having direct surface contact with the inner wall surface of the pipe to a rod-shaped guide member having a tapered surface, the centering fin is provided by the fluid force in the pipe. A probe having a structure in which the probe spreads in the tube, can directly contact the inner wall of the tube, and the centering force of the probe main body is retained by the fluid force was created. Also, in order to run inside the pipe while maintaining the centering force of the probe main body,
If a plurality of openings are provided on the upper surface of the circumference of the alignment fin and the fluid is discharged from the openings, the fluid brings about the effect of the lubricant, so that the contact resistance with the inner wall of the pipe can be reduced.

In order to achieve the above objectives based on the principles described above,
The probe for ultrasonic flaw detection in a pipe of the present invention includes an aligning member that is used by being fitted to a pipe that is an inspection object, an ultrasonic probe main body supported by the aligning member, and the probe. An ultrasonic probe for insertion into a tube having a signal cable connected to a probe main body, comprising: (a) at least a pair of adjusting surfaces having tapered surfaces concentrically attached to both end faces of the ultrasonic probe main body. A core member guide rod is provided, and (b) an inner cylinder externally fitted to the guide rod having the tapered surface, an outer cylinder fitted to a pipe to be inspected, and a connecting portion of the inner and outer cylinders. And (c) a through hole is provided in the outer cylindrical portion of the aligning member, and (d) the aligning member has a structure divided in the circumferential direction. The diameter of the outer cylinder expands and contracts as the inner cylinder slides along the tapered surface of the guide rod. Characterized by being configured to so that.

[Action]

According to the above configuration, the aligning member receives hydraulic pressure and slides along the guide rod having the tapered surface, receives the expanding force due to the tapered surface, and adheres to the inner surface of the pipe to be inspected. The tentacle body can be correctly and concentrically held with respect to the pipe to be inspected.

Further, since a part of the fluid flows through the through hole of the outer cylinder portion of the aligning member and forms a fluid film with the inner surface of the tube of the outer cylinder portion, smooth movement is possible.

Further, since the tube to be inspected and the outer cylinder portion of the aligning member are in surface contact with each other over a wide surface, the ultrasonic probe main body can be held stably.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, a transducer 8 for transmitting and receiving an ultrasonic beam.
A pair of taper guides (a rod-shaped guide member having a taper surface) 4 is fixed to the probe main body 2 having. In this example, the taper guide 4 is directed to the left and is in the direction of expanding once.

A pair of aligning fins 3 is configured. This aligning fin is configured such that an outer cylindrical portion 3b fitted inside the heat transfer tube 1 and an inner cylindrical portion 3c fitted outside the taper guide 4 are connected by a pressure receiving portion 3a.

Reference numeral 5 denotes a taper groove provided in the taper guide, which will be described later with reference to FIG.

A through hole 6 is provided in the outer cylindrical portion 3b. Reference numeral 7 is a probe cable.

The probe having the above structure is pushed to the left in the figure by the fluid (shown by the arrow) 9.

The alignment fin 3 and the taper guide are extracted and shown in FIG. 2 (A), and the bb cross section is shown in FIG. 2 (B).
Numerals 10 and 11 are stoppers provided at both ends of the taper guide 4, respectively.

As shown in FIGS. 2A and 2B, the alignment fin 3 is divided into two in the circumferential direction. 3d is the cut line.

As shown in FIG. 2B, the taper guide 4 of this example has a dovetail-shaped taper groove 5 and is divided into two alignment fins 3.
Holding

As shown in FIG. 2 (C), when the aligning fin 3 moves to the left in the figure due to the fluid force, it expands in the vertical direction of the figure by the taper groove 5 of the taper guide 4, and its outer diameter is Dmax. Becomes

Further, when the aligning fin 3 approaches the right side of the figure as shown in FIG. 2 (D), the aligning fin 3 contracts in the vertical direction of the figure, and its outer diameter becomes Dmin.

FIG. 4 (A) shows a state in which the in-tube insertion type ultrasonic flaw detection probe 18 is inserted into the heat transfer tube 1'of the helical coil type steam generator, and FIG. 4 (B) shows an enlarged detail of the b'part. . A probe for ultrasonic flaw detection (not shown in FIG. 4) having a structure shown in FIG. 1 is a vapor outlet from a pump (not shown) connected to a driving device (not shown) by fluid pressure. Spiral heat transfer tube 1'connected to tube sheet 15
You can push inside.

In this case, the probe cable 7 pulled out from the rear end portion of the probe main body 2 (not shown) has a large number of pressure receiving bodies 18 (FIG. 4) mounted at appropriate intervals over the entire length thereof. (See (B)) and travels simultaneously with the probe main body 2 (not shown).

In order to detect the traveling position of the probe main body 2 (not shown), the length traveled by the rotating tool of the drum (not shown) around which the probe cable 7 is wound. Can be detected. A continuous position signal can be obtained only by this detection signal. However, it is necessary to further detect the pressure receiving bodies 18 attached at constant intervals on the probe cable 7 and detect the insertion length from the number of the passing pressure receiving bodies 15. Thus, the position can be detected more accurately.

This insertion method and traveling direction are suitable for inspection inside a small-diameter, long tube as described above.

FIG. 5 is an explanatory view showing a situation in which the centering fins 3 divided into two parts can easily pass even when the welded portion W and the like are present inside the heat transfer tube 1.

By grasping the amount of sagging of the welded portion W in the heat transfer tube 1 in advance, by selecting the taper and stroke L of the taper guide 4 as described in FIGS. 2 (C) and (D).
If Dmax and Dmin are set appropriately, it can easily pass.

FIG. 6 shows an embodiment different from the one described above. By disposing two aligning fins with different orientations on the probe main body 2 in the front part and two in the rear part, the running performance during insertion or withdrawal is improved. Smoothed out. Due to the fluid force 9, the two alignment fins (for example, the front alignment fin 3) perform different operations. One is expanded by the fluid force 9, and the other is closed by the fluid pressure 9. Therefore, it is possible to freely switch depending on the pressure direction at the time of insertion and withdrawal, and to smoothly insert the ultrasonic probe in the pipe. It is also equipped to drive.

〔The invention's effect〕

As described in detail above, when the present invention is applied, the ultrasonic probe can be held in the correct position even for a sheep intestine-shaped tube or a spiral tube, and for changes in the tube inner diameter. It has an excellent practical effect of being able to adapt smoothly.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pipe insertion type ultrasonic flaw detection probe according to an embodiment of the present invention. FIG. 2 is a detailed view of the alignment fin shown in FIG. 1 extracted and drawn. FIG. 3 is an explanatory diagram of a conventional ultrasonic probe for ultrasonic flaws inserted in a tube. FIG. 4 is an explanatory view of the usage state of the embodiment of the present invention, and FIG. 5 is an explanatory view of the same action and effect. FIG. 6 is a sectional view of an embodiment different from the above. 1 ... Heat transfer tube, 2 ... Probe main body, 3 ... Alignment fin,
4 ... taper guide, 5 ... taper groove, 6 ... through hole.

Claims (1)

[Claims] 1. An aligning member used by being fitted to a pipe which is an inspection object, an ultrasonic probe main body supported by the aligning member, and a signal connected to the probe main body. A probe for inserting ultrasonic wave in a tube having a cable, (a)
At least a pair of aligning member guide rods having concentrically attached tapered surfaces are provided on both end faces of the ultrasonic probe main body, and (b) an inner cylinder externally fitted to the guide rods having the tapered surfaces. And an outer cylinder fitted to the pipe to be inspected, and a connecting portion for connecting the inner and outer cylinders to each other, and (c) a through hole is formed in the outer cylinder portion of the centering member. Provided,
(D) The aligning member has a structure divided in the circumferential direction, and the diameter of the outer cylindrical portion of the aligning member expands as the inner cylindrical portion slides along the tapered surface of the guide rod. ， A tube insertion type ultrasonic flaw detection probe characterized by being configured to contract.