JPH0538563U - Dual element probe - Google Patents

Abstract

(57) [Abstract] [Purpose] To extend the life of a two-transducer probe equipped with a transmitting oscillator and a receiving oscillator at high temperatures. [Structure] The oscillators for transmission and the oscillators for reception mounted on the delay material are symmetrically arranged with an acoustic blocking material between them, and the material contains closed cells having a high continuous use temperature and a small acoustic impedance value. A fluororesin foam material is used. Therefore, the probe can have a long life when used at high temperature, can detect small defects near the surface of the test material, and can measure the thickness of the thin test material.
Furthermore, acoustic coupling between the transducers is reduced, and the sensitivity of the probe can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 In this invention, for example, a two-transducer probe in which a transmitting oscillator and a receiving oscillator are separately arranged is provided with a long life in high temperature operation.

[0002]

[Prior Art]

FIG. 3 is a cross-sectional view showing an example of a conventional two-vibrator probe, 2-1 is a transmitting oscillator, 2-2 is a receiving oscillator, and 3-1 and 3-2 are on one end face. A delay material with an oscillator attached to provide fixed delay for ultrasonic wave propagation, 5 a shield plate used for electromagnetic shielding, 6 a back plate, 7 lead wires, 8 case, 9-1, 9-2 connectors, Reference numeral 10 is a test material, 12 is a conventional two-transducer probe, and 13 is an acoustic blocking material made of a material such as cork that has a large acoustic attenuation.

The conventional two-vibrator probe is constructed as described above, and is made of an acrylic resin or a polyimide resin, etc., each of which has a transmitting vibrator 2-1 and a receiving vibrator 2-2 attached to one end face. The delay material 3-1 and the delay material 3-2 are arranged symmetrically on both sides of the acoustic blocking material 13 having a small acoustic impedance value. The ultrasonic wave transmitting / receiving surface of the two-transducer probe 12 has a planar shape and is in contact with the test material 10 via the contact medium. The ultrasonic pulse radiated from the transmitting oscillator 2-1 reaches the receiving oscillator 2-2 through the propagation paths of the delay material 3-1, the test material 10 and the delay material 3-2, and the test material 10 It is used for defect detection and thickness measurement.

[0004]

[Problems to be solved by the device]

 In the conventional two-vibrator probe as described above, ultrasonic waves are radiated from the other end face of the delay member 3-1 provided with the flat plate-shaped transmission oscillator 2-1 on one end face. The ultrasonic wave reflected from the material 10 to be inspected is received by the receiving transducer 2-2 through the same propagation path. Between the transmitting oscillator 2-1 and the receiving oscillator 2-2, the acoustic coupling between them is blocked, so that the acoustic impedance value is significantly small and is approximately equal to air. 13 is used.

When the two-transducer probe 12 is repeatedly brought into contact with the high-temperature test material 10 through the contact medium, the material used for the acoustic blocking material 13 is fragile in strength and is damaged, resulting in long-term damage. However, stable performance cannot be obtained. Furthermore, since cork is a flammable material, when the temperature of the test material 10 rises, part of the material is burned and deteriorates, and the effect of the acoustic insulation material 13 cannot be exhibited. ..

Therefore, detection of minute defects and thickness measurement at high temperature cannot be performed stably for a long period of time. In particular, since the cork cannot be made thin, there is a problem that defects near the surface of the test material 10 cannot be detected and the thickness of the thin test material 10 cannot be measured correctly.

The present invention has been made in order to solve such a problem, and the defect detection in the vicinity of the surface of the test material 10 having a high temperature and the thickness measurement of the thin test material are stable for a long period of time. The purpose is to obtain a dual element probe that can be performed by

[0008]

[Means for Solving the Problems]

 The two-vibrator probe according to the present invention has an acoustic barrier made of fluororesin containing independent bubbles between the transmitting vibrator and the receiving vibrator.

[0009]

[Action]

 In this invention, the transmitting oscillator and the receiving oscillator, which are attached to the delay member, are arranged symmetrically with an acoustic barrier made of fluororesin containing independent bubbles. Fluororesin foams such as ethylene / tetrafluoroethylene copolymer, polytetrafluoroethylene, and tetrafluoroethylene / hexafluoropropylene copolymer contain extremely small closed cells and have extremely high continuous use temperature. Some of them have the highest value among plastics, and are flame retardant and mechanically tough.

Therefore, even if the material to be inspected having a high temperature is repeatedly contacted with the contact medium through the contact medium, the acoustic barrier material can maintain a predetermined performance for a long time without being damaged by burning or damage, and thus can operate for a long time. It can be stabilized and the life of the probe can be extended.

Since the thickness of the acoustic blocking material can be made small, the ultrasonic waves of transmitting and receiving waves cross each other in the vicinity of the surface of the material to be inspected, so that defects near the surface of the material to be inspected and thinness can be detected. The thickness of the test material can be measured with sufficient sensitivity.

[0012]

【Example】

An embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an AA sectional view of FIG. 2,3-1,3-2,5,6,7,8,9-1,9-2 are the same as the above-mentioned conventional probe, 1 is a two-transducer probe, and 4 is an independent bubble. The figure shows an acoustic insulation material made of resin with a high continuous use temperature.

In the two-vibrator probe configured as described above, the transmitting vibrator 2-1 and the receiving vibrator 2-2 made of PZT made of a ceramic material having a very high Curie point are They are attached to the slanted end faces of the delay material 3-1 and the delay material 3-2, which are made of a polyimide resin that withstands a high temperature of ℃ and has a small sound attenuation. Both delay materials have a thin metal shield plate 5 that acts as an electromagnetic shield on one side, and a sound insulation material 4 is a fluororesin foam material with a thickness of 0.3 to 0.6 mm that contains independent bubbles with a diameter of 50 μm or less. They are symmetrically arranged through and are bonded with a silicone adhesive that can withstand high temperature use.

The fluororesin used for the sound insulating material 4 includes, for example, ethylene / tetrafluoroethylene copolymer ETFE, which is mechanically tough and can be used at a high continuous use temperature of 150 to 180 ° C. It contains closed cells. Furthermore, it has excellent electrical properties and chemical stability against chemicals, and the mechanical strength of the resin is stable, so it can withstand long-term use. In addition, as the acoustic insulation material 4, the highest continuous operating temperature of 260 ° C. among plastics is shown, and the fluororesin of polytetrafluoroethylene PTFE which has the same performance as the above resin and the tetrafluorocarbon of which continuous operating temperature is 200 ° C. An ethylene / hexafluoropropylene copolymer can be used as well.

When the transmitting vibrator 2-1 connected by the lead wire 7 is energized from the connector 9-1 provided on the case 8, the ultrasonic wave from the flat plate-shaped vibrator is delayed by the delay material 3-. It is delayed in the propagation path within 1 and radiated to the test material 10. At this time, the sound insulation material 4 provided with the shield plate 5 on one side has a small acoustic impedance and a stable value due to a large number of independent bubbles contained in the interior, in addition to the electromagnetic shielding effect. Leakage of electrical signals and acoustic coupling between the trust oscillator 2-1 and the receiving oscillator 2-2 are significantly suppressed, and the generation of unnecessary signals can always be prevented.

The echo signal reflected from the test material 10 is received by the receiving vibrator 2-2 via the delay material 3-2 and output from the connector 9-2. Since unnecessary signals are reduced in the echo signal, the signal-to-noise ratio is improved and the sensitivity of the probe can be improved.

The ultrasonic beams for transmission and reception of the two-transducer probe have the same directivity and are arranged symmetrically. In addition, since the thickness of the acoustic blocking member 4 is small, the gap between the delay members can be reduced, and the beam path is formed so that the transmitted and received ultrasonic beams intersect near the surface of the test material 10. .. It is possible to detect minute defects near the surface of the test material 10 and to measure the thickness of the thin test material 10 with sufficient sensitivity from the ultrasonic wave propagation path.

As described above, the probe is a resin of ETFE, PTFE, and FEP that can withstand continuous use, especially at high temperature, as the acoustic blocking member 4 that suppresses acoustic coupling between the oscillators and other delay elements. By using, the stable performance can be obtained for a long period of time even if the probe 10 comes into contact with the test material 10 having a high temperature through the contact medium, and the probe can have a long life.

[0019]

[Effect of the device]

 As described above, the present invention has a simple structure in which the transmitting oscillator and the receiving oscillator mounted on the delay member are symmetrically arranged with the acoustic insulating material made of fluororesin foam material interposed between them. Since the acoustic insulation material with high temperature is used, the life of the probe used at high temperature can be extended. Since the acoustic barrier material can be made thin, it can contribute to the detection of defects near the surface and the thickness measurement of thin test materials. This has the effect of reducing acoustic coupling between transducers and improving the sensitivity of the probe.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing an example of a conventional dual element probe.

[Explanation of symbols]

 2-1 Transmitter oscillator 2-2 Receive oscillator 3-1 and 3-2 Delay material 4 Acoustic blocking material 5 Shield plate

Claims (4)

[Scope of utility model registration request] 1. A two-vibrator probe in which a transmitting oscillator and a receiving oscillator are disposed with an acoustic blocking member interposed therebetween, and an acoustic blocking member made of fluororesin containing closed cells is provided between the transducers. A two-transducer probe characterized by suppressing acoustic coupling. 2. The dual oscillator probe according to claim 1, wherein the fluororesin is an ethylene / tetrafluoroethylene copolymer. 3. The dual oscillator probe according to claim 1, wherein the fluororesin is polytetrafluoroethylene. 4. The fluororesin is tetrafluoroethylene /
The two-transducer probe according to claim 1, which is a hexafluoroethylene copolymer.