JP2005077196A - Ultrasonic measuring instrument - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic measuring instrument capable of obtaining a stable water column in which no air bubbles are entrained. <P>SOLUTION: This ultrasonic measuring instrument is constituted so that the water column is formed between the surface of an object to be measured and the ultrasonic transmitting/receiving part la of an ultrasonic sensor 1 and ultrasonic waves are propagated through the water column to perform the measurement of the dimension of the object to be measured and the detection of an internal flaw in a non-contact state and equipped with a housing 2 having an opening part 10 opened to the surface of the object to be measured, the ultrasonic sensor 1 arranged in the housing 2 to turn the ultrasonic transmitting/receiving part 1a to the opening part 10, a nozzle 3 having jet orifices 4 arranged so as to surround the outer periphery of the housing 2 or so as to leave a predetermined interval in the peripheral direction of the housing 2 to obliquely eject water to the surface opposed to the ultrasonic transmitting/receiving part la of the object to be measured and a pressure reducing device 18 for reducing the pressure in the housing 2 in order to guide water into the housing 2 from the opening part 10. The water ejected from the jet orifices 4 to collide with the surface of the object to be measured is guided to the opening of the housing 2 to form the water column. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ultrasonic measurement device used for measuring a dimension of an object to be measured and a device for detecting internal defects.

Conventionally, as an ultrasonic measurement device, for example, one having a structure disclosed in Patent Document 1 or Patent Document 2 is known.
In this type of ultrasonic measurement apparatus using an ultrasonic pulse / echo method, an ultrasonic sensor (hereinafter referred to as “sensor”) is mounted inside an ultrasonic sensor nozzle (hereinafter referred to as “nozzle”).
Each of these nozzles is provided with a housing that is coaxial with the sensor and has a substantially cylindrical shape and surrounds the sensor. A water supply port is provided on the peripheral wall of the housing, and a water injection port is formed on the side that transmits and receives the ultrasonic waves oscillated from the sensor (hereinafter referred to as the ultrasonic transmission / reception unit side). In addition, the water supplied from a water supply port flows through the predetermined flow path in a nozzle toward the ultrasonic transmission / reception part side of a sensor, and is injected from an injection port.

Then, a water column that becomes an ultrasonic medium is formed between the surface of the object to be measured and the ultrasonic transmission / reception unit of the sensor by water ejected from the nozzle, and the ultrasonic wave oscillated from the sensor to the object to be measured is generated. It propagates in the water column and is reflected between the object to be measured and the ultrasonic transmission / reception unit.
A part of the ultrasonic wave incident on the object to be measured is reflected as, for example, an echo E1 from the surface (or back surface) of the object to be measured, while the ultrasonic wave entering the object to be measured is reflected on the back surface (or internal defect). Reflecting as the echo E2, the measurement of the dimension of the object to be measured and the flaw detection of the internal defect can be performed by the time interval between the reflected echoes E1 and E2.
JP-A-7-256315 Japanese Patent Publication No.55-28015

When measuring the dimensions of the object to be measured and flaw detection of internal defects using the ultrasonic pulse / echo method described above, it is formed by water sprayed from the nozzle outlet to the object to be measured in order to improve measurement accuracy. It is necessary to reliably prevent air bubbles from being caught in the water column.
However, for example, in the techniques described in Patent Documents 1 and 2, when the dynamic pressure inside the nozzle increases, the static pressure may become a negative pressure.

Here, Bernoulli's formula is shown in Formula 1.
^{P + ρV 2/2 + (} ρgh) = constant [Equation 1]
Where P is pressure, ρ is the specific weight of the fluid, V is the flow velocity, g is the gravitational acceleration, and h is the height from the reference plane.
That is, as can be seen from Equation 1, the more the flow velocity V becomes faster, because the pressure of the flow pV ^2/2 (dynamic pressure) is increased, so that the pressure P (static pressure) is reduced. Therefore, since the injection speed of high-pressure water is fast, the pressure P (static pressure) may be negative. At this time, since the atmosphere around the water column is air, it is easy for air to enter the water column from the outside, and there is a high possibility that air bubbles are caught in the water column and mixed.

Moreover, although high pressure water is used to continuously form the water column, for example, when a pump is used as power, pulsation may occur. At this time, if there is a break (mixture of an air layer) in the water column, there is a risk of erroneous detection.
As described above, the conventional nozzle structure has a problem that it is difficult to reliably eliminate the mixing of bubbles into the water column.
The present invention has been made paying attention to the above-described problems, and an object of the present invention is to provide an ultrasonic measurement apparatus capable of obtaining a stable water column without bubble entrainment.

  In order to solve the above problem, the invention according to claim 1 is characterized in that a water column is formed between the surface of the object to be measured and the ultrasonic transmission / reception unit of the ultrasonic sensor, and the ultrasonic wave is propagated in the water column. In an ultrasonic measurement apparatus that performs non-contact measurement of a dimension of an object to be measured and flaw detection of an internal defect, a housing having an opening that opens toward the surface of the object to be measured, and the housing disposed inside the housing The ultrasonic transmission / reception of the object to be measured with the ultrasonic sensor having the ultrasonic transmission / reception unit facing the opening and the injection port arranged around the outer periphery of the housing or at a predetermined interval in the circumferential direction. A nozzle that injects water obliquely toward the surface facing the part, and a decompression device that decompresses the interior of the housing in order to guide water from the opening to the interior of the housing. Jetted Serial is characterized by forming the water column to induce water impinging on the surface of the object to be measured on the opening side of the housing.

According to the invention which concerns on Claim 1, the opening part outer periphery of the housing is surrounded by the injection port of the nozzle. Therefore, it is possible to form a water jacket (water film) that surrounds the opening with water jetted from the jet port.
And the water which was injected from the injection port and collided with the surface of the object to be measured loses the kinetic energy due to the collision, so the dynamic pressure is lowered and the static pressure is relatively increased. Therefore, this “water with high static pressure and low dynamic pressure” (hereinafter referred to as “low-pressure water”) is filled directly under the opening, and this low-pressure water can be surrounded by a water jacket (water film). It has become. In particular, in the present invention, water is jetted obliquely toward the surface facing the ultrasonic transmission / reception unit. Therefore, a water jacket (water film) that surrounds the area directly below the opening is suitably formed, and low-pressure water easily flows directly below the opening.

Furthermore, since the low-pressure water is guided and drawn from the opening into the housing decompressed by the decompression device, the interior of the housing can be filled with the low-pressure water. Therefore, a water column made of low-pressure water can be formed between the surface of the object to be measured and the ultrasonic transmission / reception unit of the ultrasonic sensor.
Since the water column formed in this way has a low flow velocity V (low dynamic pressure), the pressure P (static pressure) becomes relatively large, and air enters the water column directly from the periphery of the water column. There is almost no.

  Therefore, it is possible to provide an ultrasonic measurement apparatus that can obtain a stable water column without entrainment of bubbles. Further, for example, even when pulsation occurs in the pump, the effect is such that the water jacket (water film) formed by the jetted water is cut, and the water column itself is hardly affected. Therefore, even in such a case, since a stable water column can be formed, detection accuracy can be improved.

The invention according to claim 2 of the present invention is the ultrasonic measurement apparatus according to claim 1, wherein the flow path in the nozzle is provided with a rectifying plate.
According to the second aspect of the present invention, since the flow path in the nozzle is provided with the rectifying plate, the vortex and turbulence in the water jacket (water film) formed by the water ejected from the ejection port can be suppressed. It is. Therefore, it is possible to suitably prevent bubbles from entering the water jacket (water film). Therefore, since a water column surrounded by a stable water jacket (water film) can be formed, a stable water column free from entrainment of bubbles can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the ultrasonic type measuring device which can obtain the stable water column without entrainment of a bubble can be provided.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram illustrating an embodiment of an ultrasonic measurement device according to the present invention.
As shown in the figure, the ultrasonic measurement apparatus includes a housing 2 having an opening 10 that opens toward the surface of the object to be measured 100, and a front end that is disposed inside the housing 2 and is an ultrasonic transmission / reception unit. The sensor 1 has the surface 1 a directed toward the opening 10, the exhaust pump 18 that is a decompression device that depressurizes the inside of the housing 2, and the nozzle 3 having the injection ports 4 surrounding the entire periphery of the opening 10.

The housing 2 is configured by combining a housing upper metal fitting 12 and a housing lower metal fitting 13 with each other.
Specifically, the housing upper metal part 12 includes an upper surface part 12a having a sensor connector mounting part 12c provided substantially at the center of the upper end surface for passing the wiring of the sensor 1, and an upper cylinder continuous to the outer periphery of the upper surface part 12a. Part 12b. A female screw 12d that is screwed into the lower metal fitting 13 is provided on the inner peripheral surface below the upper cylindrical portion 12b. An exhaust port 14 is provided on the peripheral wall of the upper cylindrical portion 12b, and an exhaust port connector 15 is connected to the exhaust port 14. The exhaust port connector 15 is connected to a pipe 16, and the pipe 16 is connected in parallel to a pressure regulating valve 17 and an exhaust pump 18.

  The lower housing part 13 includes a lower cylindrical part 13a formed on the outer periphery of a male screw 13d that is screwed into the female thread 12d of the upper housing part 12 and extending downward, and a lower cylindrical part that is continuous with the lower cylindrical part 13a. A housing lower part 13b having a substantially conical cylindrical shape with a diameter reduced downward from the lower end of the part 13a and an opening 10 opened at the center of the lower end of the housing lower part 13b are integrally formed. Thus, the housing 2 is constituted by the upper surface portion 12a, the upper cylindrical portion 12b, the lower cylindrical portion 13a, and the substantially conical cylindrical lower housing portion 13b.

  An annular sensor support plate 20 is disposed on the lower side of the lower cylindrical portion 13a of the lower housing fitting 13. In the sensor support plate 20, through holes 20 a having a circular cross section and penetrating in the vertical direction are formed at predetermined positions (pitch) at a plurality of locations in parallel with the axial direction of the sensor 1. The outer shape of the sensor support plate 20 is formed in alignment with the inner shape of the lower cylindrical portion 13a, and is coaxial with the sensor 1 at the center of the sensor support plate 20 and can be fitted to each other in alignment with the outer shape. A sensor mounting hole 20b is formed. Therefore, the sensor 1 inserts the sensor support plate 20 through the opening in the upper portion of the lower metal fitting 13 and fixes it at a predetermined position in the housing 2 axial direction, and the front end face 1a side of the sensor 1 via the sensor support plate 20 is a lower cylindrical portion. It can be fixed inside 13a. In addition, the axis | shaft of the sensor 1 and the opening part 10 is coaxial, and the opening part 10 is located in the position facing the front-end surface 1a of the sensor 1. FIG.

And the base end side of the sensor 1 can be assembled | attached to the sensor connector attaching part 12c of the upper metal fitting 12 via a waterproof packing and an attachment metal fitting (not shown). Further, the wiring connector 1 b of the sensor 1 is arranged in a state of being exposed to the outside from the axial center portion on the upper surface of the housing 2. The wiring connector 1 b is connected to the control device 9 via the wiring 8.
On the outer periphery of the housing 2, a nozzle 3 including a substantially conical cylindrical partition wall 3 b that surrounds the opening 10 with a predetermined interval is attached.

  More specifically, the nozzle 3 is formed as an injection port 4 that injects water obliquely toward the surface of the object 100 to be measured that surrounds the entire circumference of the opening 10 and faces the front end surface 1a. doing. And the water supply port 24 is provided in the substantially conical cylindrical diameter expansion side peripheral wall of the partition part 3b of the nozzle 3, The connector 25 for water supply is connected with this water supply port 24. As shown in FIG. The water supply connector 25 is connected to a pipe 26, and the pipe 26 is relayed by a pressure regulating valve 27 and connected to a water supply pump 28.

  The nozzle 3 also includes an annular rectifying plate 22 in the flow path in the nozzle 3. The rectifying plate 22 is jetted by the nozzle 3 with a circular cross section so that water is jetted toward the surface of the object 100 to be measured facing the front end face la of the sensor 1 (in the direction of arrow A shown in the figure). The straightening holes 22a penetrating along the direction are formed at a plurality of locations with a predetermined interval (pitch). The inner and outer shapes of the rectifying plate 22 are formed so that they can be assembled in alignment with the outer shape of the housing lower portion 13b of the lower housing fitting 13 and the inner shape of the partition wall portion 3b of the nozzle 3 on the reduced diameter side of the substantially conical cylinder. Has been. A pressure equalizing chamber 23 is constituted by a space in the nozzle 3 surrounded by the upper surface of the rectifying plate 22.

Next, the operation and effect of the above-described ultrasonic measurement apparatus will be described with reference to FIGS. 1 and 2 as appropriate.
In this ultrasonic measuring device, when high-pressure water (water) reduced in pressure to an appropriate pressure by a pressure regulating valve 27 through a pipe 26 from a water supply pump 28 is supplied from a water supply port 24 provided in the nozzle 3, It flows in the pressure equalizing chamber 23 downward (see FIG. 1).

  Then, as shown in FIG. 2A, the high pressure water supplied from the water supply port 24 is filled into the pressure equalizing chamber 23, and the high pressure water is guided to the lower rectifying plate 22 and injected from the injection port 4. The The injection port 4 of the nozzle 3 surrounds the outer periphery of the opening 10 of the housing 2. Therefore, a water jacket (water film) 150 surrounding the opening 10 can be formed by the jetted water. In particular, in this ultrasonic measurement apparatus, water is injected obliquely toward the surface of the object 100 to be measured facing the front end face 1a, which is an ultrasonic transmission / reception unit. (Water film) 150 is suitably formed. The high-pressure water is supplied from the water supply port 24 in a necessary and sufficient amount corresponding to the injection amount. Therefore, the pressure equalizing chamber 23 is always filled with high-pressure water.

  As shown in FIG. 2 (b), the water that has been injected from the injection port 4 and collided with the surface of the object 100 to be measured loses kinetic energy due to the collision. Relatively high. Therefore, this “water with high static pressure and low dynamic pressure” (hereinafter referred to as low-pressure water 200) can be filled directly under the opening 10, and the low-pressure water 200 can be surrounded by the water jacket (water film) 150. .

Further, as shown in FIG. 2C, since the inside of the housing 2 is decompressed by the exhaust pump 18 that is a decompression device, the low-pressure water 200 can be guided and drawn into the housing 2 from the opening 10. it can.
And as shown in FIG.2 (d), the inside of the housing 2 can be filled with this low-pressure water 200. FIG. Therefore, a water column made of the low-pressure water 200 can be formed between the surface of the DUT 100 and the front end face 1 a that is the ultrasonic transmission / reception unit of the sensor 1. Note that the pressure-reducing valve 17 connected in parallel with the exhaust pump 18 can appropriately manage the reduced pressure state in the housing 2. Therefore, it is possible to easily adjust the water level of the low-pressure water 200 so that the low-pressure water 200 is filled between the surface of the DUT 100 and the front end surface 1a of the sensor 1 and the state is maintained. it can.

  As described above, in the ultrasonic measurement apparatus according to the present invention, the ultrasonic wave oscillated from the sensor 1 to the object to be measured 100 is propagated in the water column made of the low-pressure water 200 and the object 100 to be measured. It can enter and reflect between the front end face 1a of the sensor 1. Then, similarly to the above-described conventional ultrasonic measurement apparatus, the ultrasonic wave incident on the device under test 100 is reflected as, for example, an echo E1 from the surface of the device under test 100, while entering the inside of the device under test 100. The ultrasonic wave reflected as an echo E2 by the internal defect, and the internal defect of the DUT 100 can be detected in a non-contact manner by the time interval between these echoes E1 and E2.

  At this time, in order to improve the measurement accuracy, air bubbles are reliably prevented from being mixed into the water column formed between the surface of the object to be measured 100 and the front end surface 1a which is the ultrasonic transmission / reception unit of the sensor 1. Although it is necessary, according to this ultrasonic measurement apparatus, the water column formed by the low-pressure water 200 has a small flow velocity V (dynamic pressure is low), so that the pressure P (static pressure) is relatively large, Air hardly enters the water column directly from the periphery of the water column. Therefore, it is possible to provide an ultrasonic measurement apparatus that can obtain a stable water column without entrainment of bubbles.

Further, for example, even when pulsation occurs in the water supply pump 28, the influence is such that a break is generated in the water jacket (water film) 150 formed by the jetted water, and the water column itself composed of the low-pressure water 200. It is difficult to substantially affect Therefore, even in such a case, since a stable water column can be formed, detection accuracy can be improved.
Further, in this ultrasonic measurement apparatus, since the flow rectifying plate 22 is provided in the flow path in the nozzle 3, eddy currents and turbulence in a water jacket (water film) 150 formed by water jetted from the jet port 4. The flow can be suppressed. For this reason, bubbles are prevented from entering the water jacket (water film) 150. Therefore, since the water column made of the low-pressure water 200 surrounded by the stable water jacket (water film) 150 can be formed, it is possible to obtain a more stable water column with no entrainment of bubbles.

  Further, since this ultrasonic measuring apparatus can form a water column made of low-pressure water 200 surrounded by a water jacket (water film) 150, the surface of the object 100 to be measured is measured by moving the object 100 to be measured. Even if the position is displaced or the facing distance between the housing 2 and the device under test 100 varies, interference between the surface of the device under test 100 and the nozzle 3 can be prevented. Therefore, for example, it is possible to accurately measure defects inside the steel sheet while continuously moving the steel sheet online.

  The ultrasonic measurement apparatus according to the present invention is not limited to the above embodiment. For example, in the above embodiment, the entire sensor 1 is disposed inside the housing 2, but the present invention is not limited to this, and the low-pressure water 200 is interposed between the DUT 100 and the front end face 1 a of the sensor 1. The present invention can be applied to any structure that forms a water column made of and propagates ultrasonic waves in the water column. For example, the structure which arrange | positions only the front-end surface 1a part in the housing 2 can be illustrated.

Moreover, although the said embodiment demonstrated the case where the injection port 4 of the nozzle 3 was made circular and the water jacket (water film) 150 surrounding the perimeter of the opening part 10 was formed, it is limited to this. is not.
For example, if the position of the injection port 4 is a distance within a range in which the water jacket (water film) 150 can be formed, the injection port 4 can be provided slightly apart from the opening 10, for example, above the housing 2. is there.

  Moreover, in the said embodiment, although the injection port 4 is made into an annular | circular shape and it surrounds the perimeter of the opening part 10, the injection port 4 itself does not necessarily need to surround the perimeter, The water jacket (water film) 150 May be formed so as to substantially surround the entire circumference of the opening 10. For example, in the above-described embodiment, the configuration of the portion that connects the nozzle 3 and the housing 2 to each other is a beam that connects the nozzle 4 side of the nozzle 3 and the vicinity of the opening 10 side of the housing 2 (becomes a non-injection port). A configuration such as

Further, for example, the injection port 4 that surrounds the opening 10 at a predetermined interval in the circumferential direction of the opening 10 and injects water toward the surface of the object to be measured 100 facing the front end surface 1a of the sensor 1 may be used. At this time, it is desirable that the predetermined intervals are equal. For example, a configuration in which eight injection ports 4 are formed at intervals of 45 ° in the circumferential direction of the opening 10 can be exemplified.
Moreover, although the case where the nozzle 3 was directly fixed to the housing 2 was described in the above embodiment, the present invention is not limited to this, and the nozzle 3 may be fixed to a support body other than the housing 2. . However, in order to make the apparatus compact, it is preferable to adopt the configuration of the above embodiment.

Further, in the above embodiment, the outer shape of the nozzle 3 is a substantially conical cylinder shape, but the present invention is not limited to this, and for example, it may be a cylindrical body having a rectangular or elliptical cross section. Any shape can be used as long as the above effects are achieved.
Moreover, in the said embodiment, although the baffle plate 22 has formed the baffle hole 22a from several circular holes, it is not limited to this, If it is a shape which can suppress a vortex | eddy_current and a turbulent flow, Even other shapes can be suitably employed. For example, a rectifying plate in which a plurality of rectifying holes each having a hexagonal cross section are arranged in a honeycomb shape may be used.
Moreover, in the said embodiment, although the baffle plate 22 is used, it is not necessarily required and it is not necessary to use a baffle plate. However, in order to construct a stable nozzle that can suppress vortex and turbulent flow, it is desirable to use a current plate.

Next, an embodiment to which the ultrasonic measurement apparatus according to the present invention is applied will be described.
In this example, the main dimensions in the above embodiment are that the inner diameter of the housing 2 (upper and lower cylindrical portions 12b, 13a) is φ180 mm, the diameter of the opening 10 of the housing 2 is φ74 mm, and from the opening 10 of the housing 2 The length Lb to the surface of the DUT 100 is 15 mm. The predetermined length L from the front end face 1a of the sensor 1 to the object to be measured 100 is 23 mm as a reference dimension. The length L can be set in the range of 23 mm to 39 mm.

The diameter of the rectifying hole 22a of the rectifying plate 22 is φ6.0 mm, and the predetermined interval (pitch) between the adjacent rectifying holes 22a is 1.28 Dw (where Dw is the diameter of the rectifying hole 22a). And although the flow path length B (refer FIG. 1) of the baffle plate 22 is so preferable that it is large, it is 5 mm in the present Example.
In this example, the defects inside the steel plate were measured while continuously moving the steel plate as the DUT 100 on-line. In FIG. 1, the moving direction of the steel sheet is indicated by an arrow D. In forming the water jacket (water film) 150, the total pressure area of the injection port 4 based on the above-described formula 1 is set so that the static pressure inside the water jacket (water film) 150 does not become a negative pressure. The flow rate V was adjusted.

The result of having measured the defect inside a steel plate is shown in FIG. The figure is a graph showing the relationship between the size of the detectable internal defects and the steel sheet feed speed at which the size of the internal defects can be detected. The result of the conventional ultrasonic measurement apparatus is S. The results of the present example employing the ultrasonic measuring apparatus according to the present invention are shown as T, respectively.
As can be seen from the figure, in the case of detecting the same size of the internal defect, the feed rate of the steel sheet can be increased in the present invention. Although it is not uniform in the system of the present invention, it can be confirmed that the measurement area is expanded by about 20% compared to the conventional system. From this, it can be seen that in this embodiment, the size of the detectable internal defect can be increased when the feeding speed of the steel plate (object to be measured) is constant. That is, it can be seen that the detection accuracy can be improved.

It is a longitudinal section explaining an ultrasonic measuring device concerning one embodiment of the present invention. It is explanatory drawing explaining the process in which a water column is formed with the ultrasonic type measuring apparatus which concerns on this invention. It is a graph explaining the effect of the ultrasonic type measuring device concerning one example of the present invention.

Explanation of symbols

1 Sensor 1a (Sensor's) front end face (ultrasonic transceiver)
2 Housing 3 Nozzle 4 Injection port 8 Wiring 9 Control device 10 Opening portion 12 Housing upper bracket 12a Upper surface portion 12b Upper cylindrical portion 12c Sensor connector mounting portion 12d Female screw 13 Housing lower bracket 13a Lower cylindrical portion 13b Housing lower portion 13d Male screw 14 Exhaust Port 15 Exhaust connector 16 Piping 17 Pressure regulating valve 18 Exhaust pump (pressure reducing device)
DESCRIPTION OF SYMBOLS 20 Sensor support plate 22 Current plate 20a Current flow hole 23 Pressure equalizing chamber 24 Water supply port 25 Water supply connector 26 Piping 27 Pressure regulation valve 28 Water supply pump 100 Object to be measured 150 Water jacket (water film)
200 Low-pressure water A Injection direction B Channel length D Feed direction (to be measured) L Predetermined length S Result by conventional ultrasonic measurement device T Result by ultrasonic measurement device according to the present invention

Claims (2)

A water column is formed between the surface of the object to be measured and the ultrasonic transmission / reception unit of the ultrasonic sensor, and ultrasonic waves are propagated in the water column to measure the dimension of the object to be measured and to detect internal defects in a non-contact manner. In an ultrasonic measurement device,
A housing having an opening that opens toward the surface of the object to be measured; the ultrasonic sensor that is disposed inside the housing and that directs the ultrasonic transmission / reception unit toward the opening; and an ejection port of the housing. A nozzle that is disposed so as to surround the outer periphery or at a predetermined interval in the circumferential direction and injects water obliquely toward the surface of the object to be measured facing the ultrasonic transmission / reception unit, and the housing from the opening A decompression device that decompresses the interior of the housing to guide water into the interior,
An ultrasonic measurement apparatus, wherein the water column is formed by guiding water, which is injected from the injection port and colliding with the surface of the object to be measured, toward the opening side of the housing.   The ultrasonic measurement apparatus according to claim 1, wherein a flow rectifying plate is provided in the flow path in the nozzle.

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