JP3050451B2 - Ultrasonic inspection equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic inspection apparatus, and more particularly, to measuring an object to be measured in a liquid such as water by ultrasonic waves and displaying an exploration image or the like of the object. Also, the present invention relates to an improvement of an ultrasonic inspection apparatus for determining whether or not the result is acceptable.

[0002]

2. Description of the Related Art An ultrasonic inspection apparatus measures an ultrasonic wave transmitted through or reflected from a subject among ultrasonic waves emitted (transmitted) from an ultrasonic probe (hereinafter, referred to as a probe). It is possible to perform a nondestructive test on the state and characteristics of the sample. For example, an automatic inspection for internal defects can be performed along a welding line of a welded part. The ultrasonic wave used for this measurement has a characteristic that it is easily reflected by a gap where the acoustic impedance changes. Then, it is difficult to emit ultrasonic waves into the air and transmit them based on the principle that the defect measurement is performed based on this characteristic.

[0003] Therefore, in order to reliably perform ultrasonic measurement, a medium having acoustic impedance matching is required as an ultrasonic transmission medium. For example, in ultrasonic diagnosis and the like, a special jam-shaped medium is used between the probe and the subject. However, such products are expensive and require handling. Therefore, when inspecting a welded part, water is used as a medium for ultrasonic transmission from the viewpoint of inspection efficiency and the like, and water is transmitted ultrasonically while a subject (hereinafter, a work) and a probe are immersed in water. As an application medium, a water immersion flaw detection method of measuring without contacting a work is often used.

Since the measurement is performed in water as described above, the probe is immersed in water prior to the ultrasonic measurement. FIG. 5 shows a conventional input means at this time. (A) is an explanatory view of a flat probe, and (b) is an explanatory view of a focus probe. Here, 1 is a probe, 1a is its ultrasonic emission surface, 10 is air, and 11 is water. In the probe 1, the ultrasonic emission surface 1 a is usually directed to the water surface vertically below in the air 10 which is the initial position (see the broken line portion). It is moved downward into water 11 (see arrow Z). Then, the work (not shown) in the water 11 is subjected to ultrasonic measurement.

[0005]

In such a conventional ultrasonic inspection apparatus, a water immersion flaw detection method is employed, and the probe 1 is immersed in water. However, on the surface of the probe 1 after being immersed in water, air bubbles that have a strong adhesive force and do not separate with a force of about buoyancy are attached. Such bubbles 10a attached to the ultrasonic emission surface 1a ( see the enlarged view of FIG. 5C) adversely affect the transmission of the ultrasonic waves, and are usually removed by wiping or the like. It is difficult to remove even bubbles.

As a countermeasure, a surfactant is used for the purpose of reducing the adhesive force. However, water close to pure water is used in order to prevent dissolved gas and other components from being foamed by ultrasonic waves. Since it is used, contamination with a surfactant or an affinity agent is limited. Further, in some cases, an attempt is made to spray a jet jet, but rather than the effect of the jet jet, a measurement failure due to a turbulence of a medium such as a vortex in a water tank caused by this and an increase in waiting time until the flow is settled. The harm is greater. On the other hand, there is a growing demand for improved accuracy of ultrasonic measurement, and the resolution at the time of measurement basically depends on the wavelength of the ultrasonic wave. Wavelengths are increasingly being used.

However, when the wavelength of the ultrasonic wave is near Zui or less to the diameter of the bubbles adhered to the ultrasonic exit surface becomes shorter, the rate of the ultrasonic wave reflected by the air bubbles rapidly increasing difficulties in ultrasonic measurement Cause. This is problematic because highly accurate measurement cannot be performed stably and efficiently.
An object of the present invention is to solve such a problem of the prior art, and to realize an ultrasonic inspection apparatus having a configuration in which microbubbles are unlikely to adhere to an ultrasonic emission surface of a probe.

[0008]

Means for Solving the Problems] configuration of the ultrasonic inspection apparatus of the present invention to achieve the above object, an ultrasonic inspection ultrasonic measuring object immersed in a liquid by the ultrasonic probe In the device, prior to the ultrasonic measurement, the ultrasonic probe remains inclined from the vertical direction in a direction parallel to the ultrasonic emission surface of the ultrasonic probe or in a direction perpendicular to the ultrasonic emission direction. The ultrasonic probe moves into the liquid by moving the ultrasonic probe.

[0009]

In the ultrasonic inspection apparatus of the present invention having such a configuration , the ultrasonic probe advances in the direction along the ultrasonic emission surface and enters water or the like. This moving direction is a direction parallel to the flow direction when viewed relatively. Therefore, on the ultrasonic emission surface parallel to the flow, disturbance of the flow of water or the like can be reduced. For example,
It is unlikely that local negative pressure is generated due to separation of the flow, local vortex is generated while being adhered to the ultrasonic probe, and the like. Therefore, the generation of minute air bubbles that are easily attached is suppressed, and the generated air bubbles are efficiently carried away along with the flow. Therefore, the ultrasonic inspection apparatus of the present invention is less likely to cause microbubbles to adhere to the ultrasonic emission surface of the ultrasonic probe than the conventional ultrasonic inspection apparatus.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ultrasonic inspection apparatus according to the present invention will be described below with reference to FIGS.
1 is an explanatory diagram when the ultrasonic probe enters the liquid, FIG. 2 is an explanatory diagram when the ultrasonic probe is held in a horizontal state and moves in the liquid, and FIG. FIG. 4 is an explanatory diagram when the ultrasonic probe swings in a liquid, and FIG. 4 shows a driving mechanism for scanning the ultrasonic probe. Here, 1 is a probe (ultrasonic probe), 1a is its ultrasonic emission surface, 10 is air, and 11 is water. 2 is a probe rotation mechanism, 3 is an X-axis scanner, 4 is a Y-axis scanner,
Reference numeral 5 denotes a Z-axis scanner.

The probe 1 is supported by a probe rotating mechanism 2, whereby bidirectional rotation and swing are performed. Further, the ultrasonic emission surface may be directed in the vertical direction or may be inclined by a predetermined angle from the vertical direction. Further, a probe rotation mechanism 2 that holds the probe 1 is supported by a Z-axis scanner 5. Therefore, the probe 1 can be moved in any direction by the three-axis scanner including the X-axis scanner 3, the Y-axis scanner 4, and the Z-axis scanner 5.

Therefore, in order to perform ultrasonic measurement, first, data relating to a work, measurement conditions, and the like are set in an inspection apparatus. Then, the initial operation starts, and the probe 1
It goes into water 11 from inside. At this time, for example, the X-axis scanner 3, while being inclined at about 35 ° from the vertical direction,
It moves at high speed by simultaneous driving of the Y-axis scanner 4 and the Z-axis scanner 5 (see arrow A in FIG. 1). If the three axes have the same driving speed, this results in a moving speed that is approximately 1.7 times as high as the driving speed of the single axis, and the ultrasonic emission surface 1
Move parallel to a.

[0013] Then, the relative flow on the ultrasonic wave emitting surface 1a is accelerated in a laminar flow state, so that micro bubbles are hardly generated, and the generated micro bubbles are immediately carried away by the flow. When the speeds of the three-axis scanners 3, 4, and 5 of the three-axis scanner are different, these numerical values are correspondingly different. Further, even in an ultrasonic inspection apparatus having no probe rotating mechanism 2, if the probe 1 is fixed in a tilted state in relation to a work (not shown), the ultrasonic inspection apparatus corresponds to the tilt. What is necessary is just to move in parallel with the sound wave emitting surface 1a.

Further, under the condition that the ultrasonic emission surface 1a moves parallel to the ultrasonic emission surface 1a, the ultrasonic emission surface 1a may move slowly until submerged in the water 11, and may move at the maximum speed after submerging. This makes the control procedure complicated, but the generation of microbubbles due to entrainment of bubbles upon entering water can be further suppressed, and the generated bubbles are quickly carried away, so that the removal of bubbles is efficient. Done in The ultrasonic emission surface 1a of the probe 1 immersed in water as described above may be subjected to wiping or, in some cases, removal of microbubbles by spraying a jet jet, etc., in order to be more careful. In other words, the present invention does not exclude the conventional removing means, but can be used in combination with them.

In the case of the focus type probe, the ultrasonic wave emitting surface is not a flat surface but, for example, a concave surface such as an inner surface of a bowl. Therefore, a direction parallel to the ultrasonic wave emitting surface 1a cannot be directly defined. Therefore, a plane orthogonal to the ultrasonic emission direction is adopted as an average virtual plane of the ultrasonic emission plane, and a direction orthogonal to the ultrasonic emission direction as a direction parallel to the plane is the moving direction of the probe.

Next, ultrasonic measurement of the work placed in the water 11 is performed. In the apparatus of the present invention, prior to this, one of the mode selection keys of the apparatus is pressed to set the bubble removal mode. Selected. This bubble removal mode is a mode for removing minute bubbles attached to the ultrasonic emission surface 1a of the probe 1. In this selected mode,
When it is indicated that the side surface of the work is measured under the preset measurement conditions, the probe 1 is held in a horizontal state and in a direction parallel to the ultrasonic emission surface about twice the normal scanning speed. It moves in the water at high speed (see FIG. 2). Alternatively, the probe 1
Swings at high speed in water (see FIG. 3). As a result, more careful removal of microbubbles is performed.

Thereafter, ultrasonic measurement of the work is performed in the same manner as in the prior art. In the case of an ultrasonic inspection apparatus combined with a transfer robot, the workpieces are sequentially replaced, and each time the inspection process based on ultrasonic measurement is repeated. Therefore, the bubble removal mode is automatically selected for each inspection step or for several inspection steps. As a result, it is possible to prevent a decrease in measurement accuracy due to microbubbles adhered during the inspection, and it is possible to continuously perform an automatic inspection in the best state at all times.

[0018]

As can be understood from the above description, in the ultrasonic inspection apparatus having the structure of the present invention, the microbubbles are less likely to adhere to the ultrasonic emission surface of the probe than before. Therefore, the inconvenience that ultrasonic waves are reflected by the microbubbles and are not normally emitted to the work hardly occurs. In particular, high injection efficiency can be maintained even for short-wavelength ultrasonic waves for precision measurement close to the diameter of microbubbles. As a result, there is an effect that highly accurate measurement can be performed stably and efficiently.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an embodiment of an ultrasonic inspection apparatus having a configuration according to the present invention when an ultrasonic probe enters a liquid.

FIG. 2 is an explanatory diagram when the ultrasonic probe is held in a horizontal state and moves in a liquid.

FIG. 3 is an explanatory diagram when the ultrasonic probe swings in a liquid.

FIG. 4 shows a drive mechanism for scanning an ultrasonic probe in one embodiment of the ultrasonic inspection apparatus having the configuration of the present invention.

FIG. 5 is an explanatory diagram when an ultrasonic probe of a conventional ultrasonic inspection apparatus enters a liquid.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Probe 1a Ultrasonic emission surface 2 Probe rotation mechanism 3 X-axis scanner 4 Y-axis scanner 5 Z-axis scanner 10 Air 11 Water

Continuing on the front page (72) Inventor Yoshihisa Tomita 650, Kandamachi, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. 72) Inventor Kazu Mizunotani 650, Kandachi-cho, Tsuchiura-shi, Ibaraki Pref. Hitachi Construction Machinery Engineering Co., Ltd. (56) Reference: Hikaru 2-93754 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , (DB name) G01N 29/00-29/28

Claims (1)

(57) [Claims] 1. An ultrasonic inspection apparatus for ultrasonically measuring an object immersed in a liquid by an ultrasonic probe, wherein the ultrasonic probe is inclined from a vertical direction prior to the ultrasonic measurement. An ultrasonic inspection apparatus, wherein the ultrasonic probe moves in a direction parallel to an ultrasonic emission surface of the ultrasonic probe or in a direction perpendicular to the ultrasonic emission direction and enters the liquid.