JPS59155709A - Ultrasonic wave measuring equipment - Google Patents

Abstract

PURPOSE:To measure all directions of a pipe body to be inspected at the same time keeping the relative position of a srobe and a reflector held and fixed and without complex signal changes and the like by a method wherein the reflection surface of the reflector is formed to be approximately conical and an oscillator is so provided as to have its center on the same axial line as the reflector facing the reflection surface and the ultrasonic wave is radiated to all directions at the same time so that the flaw detection of all directions of the pipe body can be carried out instantly for one cross section. CONSTITUTION:A rod part 10b of the tip of a reflector 10 whose reflection surface 10a is formed to be approximately conical is inserted into a hollow part of an annular probe 9. The reflector itself is so arranged to positioned on the same axial line 9a of the probe and at the same time they are composed solidly. An ultrasonic beam C generated by an annular oscillator 8 is reflected by the facing reflection surface 10a of the reflector 10 to the apprxoimately perpendicular direction to the axis of the reflector, in other words, to the direction in the plane crossing the axis, and is propagated toward the pipe body 5. After the ultrasonic beam C reaches the pipe body 5, it is reflected by the inner surface and the outer surface of the pipe body 5 and returns to the oscillator 8 by the order opposite to that of oscillation and is received.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for detecting flaws and/or measuring wall thickness of a tube using ultrasonic waves, and particularly to an apparatus capable of measuring all directions of a tube evenly and simultaneously.

The tubes of boiler equipment, especially superheaters and reheaters of high-temperature, high-pressure power generation boilers, have high-temperature, high-pressure steam flowing inside them, and their outer surfaces come into contact with high-temperature combustion gas, so their wall thickness decreases.
Damage must be carefully investigated during regular boiler inspections to ensure boiler safety. Moreover, there is a problem in that during regular inspections, inspections of a large number of pipes must be completed in a short period of time. However, these superheater tubes are located in the combustion gas passage,
Dust and tarinka are deposited on its outer surface, and it is located near a high place, making it difficult to inspect.In addition, it requires careful inspection, and there are an extremely large number of pipes. Furthermore, in reality, it is almost impossible to carefully inspect these pipes by removing dust from the outer surface of the pipes. However, there is a strong need to develop a means that satisfies these conditions and is capable of highly reliable inspection of damage and wall thickness reduction in a large number of pipes in a short period of time.

For this reason, the inventors have devised the following device to enable inspection from inside the pipe, which is free of dust, etc., and from a safe location such as a vent house on the ceiling of the furnace.

Figures 1 and 2 are drawings showing a conventional ultrasonic measuring device in a longitudinal section. First, in FIG. 1, a vertical probe 1 and a reflector 2 that emit ultrasonic waves in the axial direction are arranged inside the probe assembly 4, and the ultrasonic waves emitted from the probe 1 The beam b is reflected by the reflector 2, changes its direction by approximately 90 degrees, and passes through the opening 4a toward the tube 5, which is the object to be examined. In this case, in order to perform flaw detection and wall thickness measurement in all directions of the pipe body (hereinafter referred to as "flaw detection"), the reflector is rotated and the ultrasonic beam b
The reflection direction of the reflector is sequentially moved in the circumferential direction of the tube, but in this case, the probe assembly (including the outer box) 4 itself of the probe and reflector pair must be formed integrally. Therefore, it is not possible to form an opening around the entire circumference of the structure. In other words, when performing omnidirectional flaw detection, the connecting portions that do not have openings act as an interference to the propagation of sound waves, making flaw detection measurements inaccurate. In addition, a motor 3 is particularly required in order to rotate the reflector 1 body 2.

Note that since the probe structure is inserted deep into the tube, it is virtually impossible to rotate this structure itself. Also, a means for displaying and communicating to the operator the direction of orientation of the reflective surface of the reflector is required.

The apparatus shown in FIG. 2 is constructed to solve the above-mentioned problems. That is, in this device, the damper material 7 is cylindrical and is made of a material that does not interfere with ultrasonic waves.
A large number of ultrasonic transducers 6 are arranged around the outer periphery of the ultrasonic transducer, and signals are sequentially switched to and received from these ultrasonic transducers by electronic scanning or the like. This eliminates the need to rotate the reflector and eliminates the occurrence of blind spots such as the non-opening portion shown in FIG. 1, but on the other hand, the probe structure becomes complicated and the apparatus becomes expensive.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus that can simultaneously measure all directions of a tube as a subject without performing complicated signal switching while keeping the relative positions of a probe and a reflector fixed.

In short, this invention forms the reflective surface of a reflector into a substantially conical shape, and arranges a vibrator with its center on the same axis as the reflector, and performs electronic scanning. The ultrasonic measuring device is characterized in that it is configured to send out ultrasonic waves in all directions at the same time without rotating the fouling body, and can instantly perform omnidirectional flaw detection on a single cross section of a pipe, etc. .

Examples of the present invention will be described below.

In Fig. 3, 9 is a ring-shaped probe (oscillator 8
), and is arranged so as to be located approximately on the same axis as the tube body 5, which is the subject.

Reference numeral 10 denotes a reflector having a reflecting surface 10a formed in a substantially conical shape, and by inserting the rod-shaped portion 10b at the tip into the hollow part of the annular probe 9, the reflector itself is aligned with the same axis as the probe. They are arranged so as to be located on the line 9a, and both are integrally constructed to constitute the main body of the measuring device. 8 is probe 9
In contrast, it is a ring-shaped vibrator arranged to face the reflective surface 10a of the reflector 10. 11 is a rod for inserting a probe attached to the probe 9, and 12 is a connector including a connection line to a power source and a transmission wire. Further, reference numeral 13 indicates a ball bearing type alignment part provided on the outer periphery of the probe 9 and the outer periphery of the reflector 10, which is screwed together with the probe 9 and the reflector 10, and is in a screwed state. By adjusting the distance between the probe 9 and the reflector]O and the inner wall surface of the tube body 5, the measuring device is centered within the tube body 5, and the device can be easily moved. Further, if necessary, it is preferable to configure the ball shown in the figure to be elastically in contact with the inner surface of the tube body 5 so as to be able to accommodate slight differences in tube diameter.

In the following two devices, the ultrasonic beam C emitted from the annular transducer 8 is approximately perpendicular to the axis of the reflector 10 at the reflecting surface 10a of the opposing reflector 10, in other words, the axis The light is reflected within a plane orthogonal to the plane and is directed toward the tube body 5.

The ultrasonic beam C that has reached the tubular body 5 is reflected by the inner and outer surfaces of the tubular body 5, and then returns to the transducer 8 and is received in the reverse order of transmission. Note that when testing a subject, a medium (for example, water) 14 is filled into the subject.

FIG. 4 shows a cathode ray tube waveform of an ultrasonic flaw detector when an ultrasonic beam is incident on the tube body 5. S indicates a reflected waveform from the inner surface of the tube, and B indicates a reflected waveform from the outer surface of the tube. In this case, the distance t from S to B represents the minimum wall thickness in all directions of the tube. Further, the distance t from this cathode ray tube waveform is configured to be displayed digitally or on a printer using a control box 23 connected to the connector 12.

Next, we will discuss the shape of the reflective surface of the reflector.

FIG. 5 shows the radiation state of the ultrasonic beam e when the reflector 101 has a conical reflecting surface 101a.
It is not parallel to θ1e2. e, becomes. In other words, there is a time difference due to the spread of the sound waves, resulting in multipath.
cause a phenomenon.

In other words, the display of the Chiso echo on the cathode ray tube has the shape shown in Figure 5A, and the spread of the sound wave is Iwo.

In addition, due to the spread of the ultrasonic waves, the ultrasonic energy is attenuated by diffusion, and the echo intensity also decreases.

On the other hand, when the cross-sectional curve of the reflective surface 100a shown in the cross-section including the axis of the reflector 100 is made to have a curvature as shown in FIG. This eliminates the distortion and increases the echo strength.

This cross-sectional curve is preferably an elliptic curve on which the ultrasound beam is focused geometrically. In that case, the spread of the sound wave:
As shown in FIG. 6A, W i is narrower than WI, fl: and the echo intensity is strong, improving measurement accuracy. Note that when the tube body has a thin part, the B1 (indicated by a dotted line) echo shown in Fig. 6A is displayed, and tm is the axis 9.
This indicates the minimum wall thickness t of the tube within the plane of the inspected location perpendicular to a. This tm can be shown on a digital display. In this case, the reflected waves (echoes) from areas with specified (standard) wall thickness are electrically removed, and the echoes from thin wall areas are sent to the control box 24, and the digital display dimensions display the minimum wall thickness within the cross section of the inspection area. It can be made into something.

FIG. 7 shows another embodiment. In contrast to the above-mentioned embodiment, in which the main body of the measuring device is placed inside the tube, the probe 18, which is placed surrounding the tube 5, is an annular vibrator attached to the probe 19. Reference numeral 15 is also a reflector placed around the tube body 5, and like the probe 19, a central cavity 151 surrounding the axis is provided. Reference numeral 15a denotes a reflecting surface formed on the end surface of the reflector 15, and in order to make the ultrasonic beam oscillated from the transducer 18 enter from the outer surface side of the tube body 5, the reflection surface 15a is formed on the axis of the reflector 15, contrary to the previous embodiment. It is formed into a concave conical surface with a concave concave surface.

An ultrasonic flaw detection device having such a structure is suitable for detecting the thickness and/or defects of a new pipe with few irregularities or scales on the outer surface. That is, by using a magnetic eddy current flaw detector or the like, new pipes continuously delivered from a pipe manufacturing factory or the like are used to inspect the central cavity 151 of the apparatus shown in FIG. 7 according to an embodiment of the present invention at a considerable speed. By passing it through the test, it is possible to perform a more reliable and accurate inspection.

Measuring the wall thickness of a pipe with a device according to an embodiment of the present invention,
The relationship between the wall thickness measured by cutting after measurement was as shown in FIG. 8, and the accuracy was +0.09 mm, which was a high precision one.

By implementing this invention, it is possible to simultaneously send an ultrasonic beam to the entire circumference of the subject in all directions and receive the reflected waves (echoes), which reduces inspection time and improves inspection accuracy. It is possible to conduct highly efficient inspections that increase

In addition, there is no need for a rotating mechanism for the reflector, an electronic scanning mechanism, etc., making the device inexpensive and simple, reducing the occurrence of failures and increasing the reliability of the device. Regular inspection of boilers for power plants, etc. This has a significant effect on shortening the inspection period and improving reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a rotating reflector type ultrasonic measuring device, FIG. 2 is a sectional view of an electronic scanning type ultrasonic measuring device, and FIG. 3 is a part of an ultrasonic measuring device according to an embodiment of the present invention. Broken side view,
Figure 4 is a CRT waveform diagram when this device is used, Figure 5 is a partial cross-sectional schematic diagram of the diffusion state of the ultrasound beam when the reflecting surface is a conical surface, and Figure 5A is the case of Figure 5. Figure 6 is a partial cross-sectional schematic diagram showing the focusing of an ultrasonic beam on a reflector with a reflective surface with curvature, and Figure 6A is a schematic diagram of the cathode ray tube display in the case of Figure 6. A schematic diagram, FIG. 7 is a longitudinal cross-sectional view of an apparatus in which a subject can pass through the central cavity of the apparatus, showing another embodiment, FIG.
The figure is a drawing showing a comparison of measured values and actual measured values when measuring a test tube. 5... Tube body 8.18... Vibrator 9.19... Probe 10.15... Reflector 10a, 15a... ... Reflective surface 10b ... Rod-shaped part

Claims (1)

[Claims] 1. In a device that detects the thickness and/or flaws of an object using an ultrasonic beam, a probe and a reflector are arranged approximately coaxially, and the shape of the transducer of the probe is The reflector is formed into an annular shape approximating the transverse inner surface shape of the object, and the reflector has a conical portion with its top facing the probe and located on the axis, and the reflector has a conical portion located on the axis of the probe. An ultrasonic measurement device characterized in that a set of a reflector and a reflector are integrally displaced within a subject and are formed so as to simultaneously radiate an ultrasonic beam in all directions in the inner peripheral direction of a cross section of the subject. 2. The ultrasonic measurement device according to claim 1, wherein the reflector is a cone with an mf ratio, in which the curve formed by the reflecting surface is a curved curve in a longitudinal section including its axis. . 3. The ultrasonic measuring device according to claim 1 or 2, further comprising a converter that digitally displays the minimum wall thickness dimension of the measured cross-sectional area. 4. The ultrasonic measuring device according to any one of claims 1 to 3, characterized in that the object to be examined is a tube, the vibrator is a substantially annular shape, and the shoe reflector is a substantially conical shape. . 5. The reflector is formed to have a concave conical part with its apex located within and above the reflector, and the object to be examined can be displaced through the central cavity of the probe and the reflector. Claims 1 to 3 characterized in that
The ultrasonic measuring device according to any one of paragraphs. 6. The ultrasonic measuring device according to claim 5, wherein the object to be examined is a tube, the vibrator is approximately annular, and the reflecting surface of the reflector is approximately a concave conical surface.