JPS6281562A - Probe for ultrasonic flaw detection - Google Patents

Abstract

PURPOSE:To certainly and automatically supply a contact medium necessary at the time of flaw detection to a necessary area only in a necessary amount, by opening an internally provided contact medium supply passage to the flaw detection surface side of a probe. CONSTITUTION:A tube 2 being a contact medium supply passage is inserted in a probe 1 and a pressure feeder 3 is connected to the other end of the tube 2. The probe 1 is connected to a measuring display apparatus 6 by a cable 5 and a vibrator 12 is obliquely mounted in the box shaped casing 11 of the probe 1. A slot 15 is bored in the central part of the vibrator 12 and the tube 2 is fixed on the upper surface of the casing 11 through said slot 15 by a boss 16 and the opening end of said tube is faced to the flaw detection surface of the probe 1 in the flaw detection surface side thereof. A contact medium can be supplied only to a specific narrow area where the probe 1 transmits an ultrasonic wave.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic flaw detection probe. More specifically, it relates to a newly developed ultrasonic probe for automatically supplying couplant used in ultrasonic flaw detection or thickness measurement.

[Prior art] Ultrasonic flaw detection and ultrasonic thickness measurement, which are types of non-destructive testing, send ultrasonic pulses from the surface of the object to the inside to detect reflections from interfaces, scratches, lattice defects, etc. The system receives the waves, converts them into electrical signals, and transmits them to a cathode ray tube or displays them digitally or prints them, thereby determining the thickness of the sample and the presence or absence of internal flaws or defects in the object being inspected.
It is used to investigate the location, size, etc. In order to make the explanation easier to understand, the following explanation will be made regarding ultrasonic flaw detection, but the present invention can be effectively applied not only to ultrasonic flaw detection but also to ultrasonic thickness measurement.

The ultrasonic flaw detector used in this method basically consists of a probe that transmits ultrasonic waves, a main body that drives and controls the probe, and a display section that analyzes, displays, and records inspection results. There are stationary types, self-driving types, and portable types.

A stationary ultrasonic flaw detector is used when the object to be inspected is moving, and the flaw detector itself is fixed.

In the automatic traveling type, the main body of the flaw detector automatically moves over the object to be inspected while being guided by rails, and the probe automatically scans the surface of the object to be inspected (hereinafter referred to as the flaw detection surface). It is especially suitable for exploring fixed buildings, large structures, and confined spaces. The portable type allows you to hold the probe in your hand and probe the area being inspected.

By the way, with any type of flaw, if there is air between the probe and the surface of the object to be inspected, the attenuation of the transmitted ultrasonic waves will increase, so it is common practice to make the surface to be ultrasonic-transparent before inspection. A superior couplant is applied.

Conventionally, couplant has been supplied to the flaw detection surface in the following manner.

(1) Apply the contact catalyst manually to the area to be detected using a brush or oiler in advance and rub it with the probe to blend it in.

(2) In the case of a traveling ultrasonic flaw detector, supply the couplant around the probe and spread it with the probe to blend it.

(3) In the case of a fixed type ultrasonic flaw detector, a large amount of couplant such as water or oil is sprayed onto the flaw detection area from around the probe to fill the gap between the probe and the flaw detection surface.

[Problems to be Solved by the Invention] However, the method (1) above has the following problems.

If left for a long time after application, the couplant may change in quality (for example, changes in the concentration and viscosity of glycerin), which is particularly noticeable at high temperatures, and has an adverse effect on flaw detection accuracy. If this is to be avoided, the coating must be applied again, resulting in a large amount of effort and loss of couplant. In addition, in the case of a highly viscous couplant, the couplant that has been pushed away by the probe may accumulate in some areas depending on the flaw detection area, and the resulting abnormal echoes may impede flaw detection. Furthermore, if an excessive amount of couplant is used, a great deal of effort is required to remove it after flaw detection, and this becomes even more troublesome especially in the case of oil. Therefore, if it is permissible, it is often the case that they are left unremoved and allowed to be exposed to the wind and rain and removed naturally. Since it is necessary to carry the couplant and applicator, there are many problems in terms of safety and work efficiency when working in difficult places, such as in narrow spaces, at heights, and when working facing upwards, which also greatly affects flaw detection accuracy.

In the method (2) above, the above-mentioned problem is solved to a large extent, but since the couplant is supplied around the probe, it is difficult to inject it into the surface to be detected reliably. In order to do this, there is a problem in that an excessive amount must be supplied or it must be applied manually in advance.

In the method (3) above, there remain problems such as the inclusion of bubbles on the flaw detection surface and the necessity of recovery work due to the dissipation of a large amount of couplant. This is especially a problem when automatic flaw detection is of a moving type.

In addition to the above-mentioned problems with the conventional technology, the following demands for ultrasonic flaw detection technology have become stronger in recent years.

Recently, the automation and robotization of flaw detection has progressed rapidly, and the demand for supplying couplant to remote locations and places that humans cannot access (such as nuclear reactors and narrow areas) is increasing. These problems cannot be met by equipment or manual coating, and although conventional methods of continuously supplying with pumps have been put into practical use, supplying in large quantities poses problems such as contamination of the working environment and difficulty in recovering the couplant. remains.

These problems are especially serious in relation to nuclear reactors, and it is strongly desired to continuously supply the minimum necessary amount of couplant at a constant rate.

On the other hand, with the progress of ultrasonic flaw detection, there is a need to detect flaws in parts with unique shapes (for example, specific parts in tubes). In this case, it may be nearly impossible to supply the couplant by hand painting, which may become a technical bottleneck in the development of new flaw detection methods.

In view of the above-mentioned circumstances, an object of the present invention is to provide a probe that can reliably and automatically supply the necessary amount of couplant to the required site during flaw detection.

[Means for Solving the Problems] The ultrasonic flaw detection probe of the present invention is provided with a couplant supply path inside the ultrasonic flaw detection probe, and the supply path is connected to the probe. A configuration with an opening on the flaw detection side is adopted.

[Function] In the present invention, the couplant is discharged to the flaw detection surface side of the probe through the couplant supply path. Since the open end of the supply channel faces the surface of the deeply damaged object, the couplant is reliably supplied to the necessary site, and only a small amount is required. Note that if a pressurized supply device for couplant is connected to the supply path, automatic supply of couplant becomes possible.

Note that the probe of the present invention can be used for both the gap method and the contact method.

[Example] Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is an explanatory diagram of a flaw detection device using a probe according to an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of a probe according to an embodiment of the present invention, and FIG. FIG. 4 is a partially cutaway perspective view of a probe according to another embodiment of the invention, and FIG. 4 is a bottom view of the probe shown in FIG. 3.

In FIG. 1, (1) is a probe used in a stationary, automatically traveling, or portable ultrasonic flaw detector. A square tube (2) serving as a couplant supply path is inserted into the probe (1), and a pressurized supply device (3) is connected to the other end. The pressurized feeder (3) feeds the couplant under pressure and is equipped with a valve (4).
By adjusting the opening amount in step 4), the amount of couplant supplied can be adjusted as desired. In addition, a cable (5) is connected to the probe (1), and electricity for generating ultrasonic waves and It is designed to send and receive echo electrical signals. (71 is the object to be inspected, the probe (1) is placed on the flaw detection surface (7a) of the surface of the object to be inspected, and flaw detection is performed without force or by moving the probe (1) in the direction of the arrow. .

Next, the implementation of the probe (1) will be explained based on FIG.

The old) is a box-shaped housing, and a transducer (+2) for generating ultrasonic pulses is installed diagonally inside the housing CI+1. 03] is a plug for connecting the cable (5), and 04) is an acrylic plate attached to the bottom of the housing. Note that an oscillation mechanism for vibrating the vibrator 02) is built into the casing 01).

A long hole 6 is bored in the substantially central part of the vibrator [+21], and reaches through it to the bottom end of the tube (2 is the old casing). That is, the tube (2) is fixed on the upper surface of the casing all by a boss aej, etc., and its open end faces the flaw detection surface (7a) on the flaw detection surface side of the probe (1). With this configuration, The couplant can be supplied only to the probe (1) or to a specific narrow area where the ultrasonic pulses are to be transmitted.

The size of the tube ('2J) is 0.5 to 1 m in outer diameter.
It is preferable to set it to about m. When using such a thin tube, there is no need to increase the size of the probe (11) or make any significant design changes;
) can also be applied. Also, vibrator 02)
This is because high flaw detection accuracy is guaranteed because it does not interfere with the ultrasonic waves emitted by the

Note that when such a thin tube (2) is used, the couplant supply resistance increases, so it is preferable to supply the couplant under pressure. Recommended.

As the pressurized feeder (3), any device can be used as long as it can stably and reliably supply a low viscosity liquid or a highly viscous liquid couplant. For example, a cylindrical pressure vessel can be used. A device that can push out the couplant filled inside with gas pressure is preferably used.

It is preferable that a valve (4) for adjusting the flow rate is attached to the pressurized supply device (3) or the tube (2).In such a case, by changing the opening degree of the valve (4), The discharge amount of the couplant can be changed depending on the viscosity of the couplant and the pressing force, and it is possible to apply the couplant effectively with the minimum necessary amount.

Note that the couplant to be used may be one that has been conventionally used. For example, water, oil, glycerin, polyvinyl alcohol solution, carboxymethyl cellulose solution,
Examples include carboxyvinyl polymer solutions, and among these, polyvinyl alcohol solutions, carboxymethylcellulose solutions, and carboxyvinyl polymer solutions, which have relatively high viscosity, are preferred. In particular, carboxyvinyl polymer solutions have excellent thixotropic properties and stable viscosity over a wide temperature range, making them ideal for exploring vertical surfaces, ceiling surfaces, inner surfaces of pipes, etc. using the gap method in all seasons.

Since the probe (1) of this example has the above-mentioned configuration, the couplant is completely filled into the gap between the probe and the flaw detection surface without rubbing the probe (1) as in the prior art. can be charged to. This not only makes flaw detection easier, but also allows the couplant to be applied uniformly, resulting in good acoustic coupling and stable echoes.

Next, other embodiments of the probe will be described based on FIGS. 3 and 4.

The probe (1) of this embodiment has a cylindrical casing, and the center of the casing [211] is partitioned vertically by a temporary partition, and two chambers are provided. Each chamber is provided with a vibrator and a delay material C4, one of which is used for wave transmission and the other for wave reception.

A hole is bored in the center of the temporary partition, and its upper end is connected to the tube (2).

The hole ■ thus constitutes the tip of the tube (2), and its open end is located on the same plane as the bottom of the casing (2'D). The outer diameter and inner diameter of the tube (2) are substantially the same as the tube (2) of the embodiment shown in Fig. 2, which is 17 degrees.
A pressurized supply (3) and a measurement display (6) may also be connected as shown in FIG.

With the above configuration, also in this embodiment, the gap between the probe and the flaw detection surface can be filled with the flaw detection medium without rubbing the couplant with the probe.

Note that the open end of the couplant supply channel does not necessarily need to be provided near the center of the probe, and the same effect can be achieved even if it is provided at the peripheral edge. In particular, when it is provided on the periphery, there is no need to drill holes in the vibrator, and changes in the design of conventional probes can be kept to a minimum.

Furthermore, the number of couplant supply channels is not limited to one;
Two or more may be arranged as appropriate.

Although the present invention has been described in detail above, various modifications can be made without departing from the gist of the present invention.

[Effects of the Invention] The following effects can be achieved in the present invention.

■Since the couplant can be directly injected from inside the probe into the narrow space between the flaw detection surface and the probe, the couplant can be applied reliably to the areas where it needs to be applied. Achieves echo stability and high reproducibility. Therefore, the reliability of the test results is increased.

■It is no longer necessary to apply a large amount of couplant, and it is possible to prevent the occurrence of abnormal echoes caused by the presence of couplant in the surrounding area.It also reduces the amount of couplant used and the hassle of application and removal work. savings can be made.

■It is easy to supply to remote locations and hard-to-reach areas, which are necessary for automation and robotization.

■For example, it is easy to add couplant to a conventional probe so that the couplant is supplied through a small diameter tube, and if it is newly designed, it does not require significant changes in shape or size. It is possible to use an automatic feeding type probe instead.

■Since it does not use machinery or electricity, it can be used either fixedly or moved at any time, and portable models can be carried around the waist.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a flaw detection device using a probe according to an embodiment of the present invention, FIG. 2 is a partially cutaway perspective view of a probe according to an embodiment of the present invention, and FIG. FIG. 4 is a partially broken pressure surface view of a probe according to another embodiment of the invention, and FIG. 4 is a bottom view of the probe shown in FIG. 3. (Main symbols in the drawing) (1): Probe (2): Tube (3): Pressure supply device (4): Valve (2Ci: hole (II), (2Il: casing (121, n: vibrator) 5. Two-parting plate patent applicant: Patent attorney representing Nippon Acetylene Co., Ltd.
Souta Asahina 1 name 71 Figure 4: Pulp 72 Figure

Claims (1)

[Scope of Claims] 1. An ultrasonic flaw detection probe in which a couplant supply path is provided inside the ultrasonic flaw detection probe, and the supply path is opened on the flaw detection surface side of the probe. Child. 2. The ultrasonic flaw detection probe according to claim 1, wherein the couplant supply path is a tube. 3. The ultrasonic flaw detection probe according to claim 2, wherein a pressure supply device capable of supplying the couplant under pressure is connected to the tube.