JPS6385442A - Ultrasonic sensor device - Google Patents

Abstract

PURPOSE:To measure the acoustic speed of a medium to be measured with high accuracy regardless of the length of an ultrasonic waveguide made of an elastic member by providing an ultrasonic wave transmitter-receiver to one end part of the ultrasonic wave guide and providing an ultrasonic wave reflecting member at a constant distance from the other end part. CONSTITUTION:When an ultrasonic wave is made incident on the waveguide 1 from the ultrasonic wave transmitter-receiver 3, its wave motion is propagated in the waveguide 1 toward the medium 5 to be measured. When the waveguide 1 contacts the medium 5 to be measured and the current acoustic wave V of the medium 5 to be measured is slower than the phase speed Vp of the waveguide 1, part of ultrasonic wave energy propagated in the waveguide 1 is emitted in the medium 5 to be measured. The ultrasonic wave entering the medium 5 to be measured reaches the reflecting member 2 and there are a wave propagated along this reflecting member 2 and a wave which is reflected here to return to the waveguide 1. At this time, the time required for the propagation in the contacting medium is measured to detect the acoustic speed of the medium to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ultrasonic sensor device, and more particularly to an ultrasonic sensor device that can remotely measure the sound speed of a fluid, etc. using leaky waves. .

[Conventional technology]

When measuring the sound speed of an object or the temperature of an object using ultrasonic waves, a configuration is adopted in which longitudinal ultrasonic waves output from one ultrasonic sensor are directly propagated through the object to be measured to the other ultrasonic sensor. There is. The majority of methods attempt to measure the sound velocity or temperature and changes thereof based on the propagation time and changes thereof of the ultrasonic waves that are repeatedly transmitted and received during this period.

[Problem that the invention seeks to solve]

Ultrasonic sensors used for monitoring high-temperature fluids or fluids under dangerous conditions, or for monitoring temperature changes in liquid hazardous materials, are required to withstand sufficiently even under these harsh environments.

However, general ultrasonic sensors consist of a composite body of a vibrator and a protector, which are integrated with a bonding material, so there is an upper limit to the operating temperature (approximately 400 ('C)); The situation was such that it was almost impossible to regularly and continuously measure temperatures of 800 ('C). In addition, many vibrators and protectors are easily contaminated chemically, and there is a disadvantage that their deterioration progresses extremely quickly, especially in environments with rapid temperature changes.

[Purpose of the invention]

The present invention improves the disadvantages of the conventional examples, and particularly targets fluids and soft materials, even if they are harmful substances or are constantly exposed to high temperatures. Provided is an ultrasonic sensor device capable of remotely measuring the speed of sound of an object and its changes with high precision, thereby making it possible to measure the temperature, viscosity, and changes thereof of the object to be measured with high precision. That,
That purpose.

[Means for solving problems]

Therefore, the present invention provides an ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member disposed at a certain distance from the ultrasonic waveguide, and an ultrasonic waveguide provided at one end of the ultrasonic waveguide. In order to achieve the above object, the ultrasonic waveguide is equipped with an ultrasonic transducer and an ultrasonic waveguide, and an ultrasonic reflecting member is provided at the other end of the ultrasonic waveguide.

[First Embodiment of the Invention] Hereinafter, a first embodiment of the present invention will be described based on FIGS. 1 to 4.

In FIG. 1, the ultrasonic sensor device consists of plate-shaped (or band-shaped) ultrasonic waveguides (hereinafter simply referred to as "waveguides") 1 arranged at a certain distance from each other and the ultrasonic waves An ultrasonic reflecting member (hereinafter simply referred to as "reflecting member") 2 formed in the same shape as the waveguide 1, and the ultrasonic waveguide 1
The ultrasonic transducer 3 is attached to one end of the ultrasonic transducer 3.

In this embodiment, the waveguide 1 and the reflecting member 2 provided opposite thereto are made of stainless steel and have the same length. The other ends of the waveguide 1 and the reflecting member 2 are disposed within a medium to be measured 5, as shown in the figure.

The ultrasonic transducer 3 is attached to the side surface of one end of the waveguide 1. Ultrasonic waves (longitudinal waves) are obliquely incident on the waveguide 1 from the ultrasonic transducer 3, and reflected propagation waves containing various information are received from within the waveguide 1 after a predetermined period of time. It is now possible to do so.

IA and 2A respectively indicate the end faces of the waveguide 1 and the reflecting member 2 as ultrasonic wave reflecting means.

Here, the wave propagating in the waveguide 1 and the propagation situation in the medium to be measured 5 will be explained.

When the waveguide 1 is brought into contact with a liquid or a fixed object, a portion of the acoustic wave energy propagating through the waveguide 1 tends to leak into the contact medium. Taking advantage of this property, for example, if a pair of waveguides (in this example, the other waveguide constitutes the ultrasonic reflecting member 2) is arranged with the above-mentioned contact medium interposed, the ultrasonic wave propagates through one of the waveguides. A portion of the acoustic wave's energy propagates through the contact medium to the other acoustic waveguide. At this time, the speed of sound in the contact medium can be detected by measuring the time required for the sound to propagate through the contact medium.

When ultrasonic waves are incident on the waveguide 1 from the ultrasonic transducer 3, the waves are directed toward the medium 5 to be measured through the waveguide 1.
propagate within. In this case, among the velocities at which the ultrasonic wave propagates in the waveguide 1, the phase velocity is set to the V22 group velocity sum v9. When the waveguide 1 is in contact with the medium 5 to be measured and the sound velocity V of the medium 5 at this time is smaller than the phase velocity vP of the waveguide 1, a part of the ultrasonic energy propagating in the waveguide 1 is transmitted to the medium 5 to be measured. radiated into the medium 5. The radiation angle θ at this time is determined by the following equation.

θ=5in-' (V/Vp) The ultrasonic wave that entered the medium 5 to be measured reaches the reflection member 2,
There are waves that propagate along this reflecting member 2 and waves that are reflected here and return to the waveguide 1 side.

Now, if the length of the waveguide 1 and the reflecting member 2 are equal, and if the interval between the waveguides is D, then if the round trip is 2 strokes, the path in the medium to be measured will be N strokes (N=L2.3.・・・・・・
) arrival time of the received wave is tN= ((21−−NDt
an θ'I /V9 )+ (ND/Vcos θ)
+τ1 +τ2...■ Here, τ1. τ2 is a fixed delay amount during transmission and reception.

Next, when calculating the difference in the case of N=2.4, Δt-2D ((1/Vcos θ)-(tan
θ/V9)) ...■ Therefore, the sound velocity V of the medium 5 to be measured can be found from the following equation.

(4D2+V, 2∆t2)V4- (8D2V, V, +VI, "V92 ∆t2) v2 + 4D2Vp" V, "=O-■ Therefore, if ∆t is measured, the measured value can be obtained from equation 0 using the known slope, V9゜■. The sound velocity V of the medium 5 is determined.

These series of calculations are performed by the main unit's calculation section (
(not shown).

Next, specific experimental results in the first example will be explained.

The waveguide 1 and the reflecting member 2 each have a plate thickness of 0.95
(n) steel plate was used, and a variable angle probe with a frequency of 1 (MHz') was used as the ultrasonic transducer 3.

The wedge of the variable angle probe is made of acrylic, and the incident angle is 31.5.
The waveguide was fixed at a certain angle so that the So mode plate wave was guided. Tap water (21 [°C]) was used as the medium to be measured.

Therefore, in this case, the group velocity of the guided wave V9. and the phase velocity V is approximately S even within the medium 5 to be measured. mode (1, 8, Viktrov, rRaylei
gh ar+d Lamb Waves JP,
117).

The applied electric pulse was a two-wave sine wave of 200 (V, .). An example of the observed received waveform is shown in FIG. In the figure, T indicates the waveform of the transmitter, and R indicates the received waveform of the receiver. N=2.4 indicates waves whose underwater paths are 2 strokes and 4 strokes, respectively. *mark indicates that the wave of N=2 is further transferred to waveguide 1
The received waveform of the wave that made one round trip is shown. In this example, Δt =
It was 75.1 (as). The group velocity of the waveguide 1 in the ultrasonic wave used is experimentally determined from the arrival time difference between the wave marked with * and the wave with N=2, and is v,=5200 (,/s).

Furthermore, the phase velocity could be calculated from the acoustic velocity of the acrylic material, 2720 (□/, ), and the set incident angle of 31.5° C. of the variable angle probe, and was V #5300 (,/,).

On the other hand, FIG. 3 shows the results of confirming the relationship of equation (2) through actual measurements while changing the spacing between the waveguide 1 and the reflecting member 2. From this, it was possible to obtain Δt/D = 1.26 Cμs/n+3. The sound speed of water can be calculated from the equation 0 using V, , V, found earlier. The results are shown in FIG. The temperature was measured at three points. The results are in very good agreement with publicly available values.

In this way, according to the first embodiment, the sound velocity V of the medium to be measured can be effectively determined regardless of the lengths of the waveguide 1 and the reflecting member 2, and By simply detecting the reception time difference of the four waves, the sound velocity V of the medium to be measured 5
Since the lengths of the waveguide 1 and the reflecting member 2 are unrelated, it is possible to remotely measure high-temperature fluids or highly dangerous fluids, and therefore the ultrasonic transducer 3 Even if you use the normal one as
This has the advantage that sufficient durability can be ensured.

Furthermore, if the insertion dimensions of the waveguide 1 and the reflecting member 2 into the medium 5 to be measured are set large, the receiving sensitivity will increase, but this has no direct relationship with the measurement accuracy. The dimensions of the medium 5 to be introduced into the medium 5 to be measured are not particularly required to be exact, and therefore, it is possible to obtain an ultrasonic sensor device having excellent properties for remote measurement, which is extremely easy to handle.

Furthermore, since the insertion dimensions into the medium 5 to be measured are directly related to the level of the ultrasonic waves received by the ultrasonic transducer 3, the liquid level of the medium 5 to be measured can be detected at the same time. There are also advantages.

Furthermore, in the first embodiment, the waveguide is formed of a plate-like member, but other members may be used.

For example, the waveguide may be formed of a round bar member, a suitable wire member, a pipe-shaped member, or the like.

[Second example] Next, a second embodiment will be described based on FIG. 5.

Here, the same reference numerals are used for the same constituent members as in the conventional example described above.

In FIG. 5, the ultrasonic sensor device includes a waveguide 1 and a reflection member 2 made of stainless steel plate members arranged at a certain distance apart, and a waveguide 1 attached to one end of the waveguide 1. an ultrasonic transducer 3, the waveguide 1 and a reflecting member 2;
and a spacer 10 inserted between one end of the two.

In this embodiment, the ultrasonic transducer 3 is of an oblique probe type and includes a piezoelectric vibrator 3A and a wedge 3B made of organic glass. The ultrasonic transducer 3 is fixed to one end of the waveguide 1 as shown in FIG.

The spacer 10 includes a block 10A made of an insulating material and sound insulating members 10B fixed to both ends of the block IOA.
It is composed of. As the sound insulation member 10B, a member having an acoustic impedance significantly different from the acoustic impedance of the waveguide 1 is used. Further, this spacer 10 is held between the waveguide 1 and the reflecting member 2 so as to be located on the opposite side of the ultrasonic transducer 3 described above. A sound absorbing member 11 is provided on the outside of the ultrasonic transducer 3.
is provided. Further, a sound insulating member 12 is provided on the outside of the reflecting member 2. The above-mentioned wave transmitter/receiver 3. waveguide l
2. The whole of the reflecting member 2 and the spacer 10 is the clamp mechanism 1.
5, and is fixed by set screws 15A and 15B of the clamp mechanism 15 as shown in FIG.

In this case, the sound insulating member 2 of the spacer 10 is generally made of a heat insulating material such as asbestos or foamed plastic that has sound insulating properties. The difference in acoustic impedance of this foamed plastic with respect to the waveguide 1 and the reflecting member 2 is 1000 to too many times larger. Therefore, the ultrasonic energy propagating to the block IOA is almost negligible.

Even in this case, the same working effect as in the first embodiment described above is obtained, and furthermore, due to the effect of the spacer 10, the mutual dimensions of the waveguide 1 and the reflecting member 2 can be effectively adjusted without interfering with the propagation of elastic waves. It has the advantage of being able to maintain

[Third Embodiment] Next, a third embodiment will be described based on FIGS. 6 and 7.

In this third embodiment, a waveguide 1 and a reflecting member 2 having the same length and circular cross section are provided, and sound collection guide portions 43A and 44A are provided at one end of the waveguide 1 and the reflecting member 2, respectively. An ultrasonic transducer 43 is attached to the waveguide 1 via one of the sound collection guide parts 43A, and an ultrasonic transducer 43 is installed between the waveguide 1 and the reflecting member 2 in the vicinity of the transducer 43. The structure is equipped with a spacer 45. This spacer 4
5 is a sound insulating member 4 at the contact portion between the waveguide 1 and the reflecting member 2.
It has 5A and 45B.

The other ends of the waveguide 1 and the reflecting member 2 are formed relatively sharply, and a notch 4 as an ultrasonic reflecting means is provided on the waveguide 1 and the reflecting member 2 close to the sharp ends 41A and 42A.
1B and 42B are formed, respectively.

Therefore, in this third embodiment, the waves propagated along the waveguide 1 are reflected by the notch portion 41B and detected by the ultrasonic transducer 43. The third embodiment is suitable for measuring the sound velocity of a solid object, which is a soft member. Other configurations and effects are as follows:
This is substantially the same as the first embodiment described above.

In each of the above embodiments, the spacer 10.45 is connected to the waveguide 1.
In the above example, the spacer is installed at one end of the reflecting member 2 or is not used, but if the spacer has a range or structure that does not interfere with the propagation of leaky waves, it can be installed at the tip (other end), for example. It may be equipped in multiple locations, such as in multiple locations.

[Fourth example] Next, a fourth embodiment will be explained with reference to FIG.

In the embodiment shown in FIG. 8, a spacer member 20 is attached between the other ends of the ultrasonic waveguide 1 and the ultrasonic reflecting member 2 in the second embodiment described above. In this spacer member 20, sound insulating members 208 and 20B are provided at the waveguide 1 and reflection member 2 portions, respectively, thereby preventing ultrasonic energy from leaking from around the other end. The other configurations are completely the same as the second embodiment described above.

Even in this case, in addition to having the same effect as the second embodiment described above, there is an advantage that minute vibrations at the other ends of the waveguide 1 and the reflecting member 2 are eliminated, thereby improving measurement accuracy. .

Furthermore, the waveguide 1 and the reflecting member 2 may have arcuate cross-sections facing each other, as shown in FIG. 9. In this case, the waveguide 1 and the reflecting member 2 have an extremely high efficiency in moving the sound wave energy from one side to the other due to the mutual lens action, and at the same time, when the width B of the waveguide 1 cannot be made very large Waveguide 1
Since it has the effect of increasing the rigidity of the material, it is effective when measuring the sound velocity of soft tissue, etc.

[Fifth Example] Next, a fifth example will be described based on FIG. 10. In the embodiment shown in FIG. 10, the ultrasonic reflecting member 2 is formed of a cylindrical member, and a rod-shaped ultrasonic waveguide 1 is disposed on the center line of the reflecting member 2, and a sound insulating member is attached to one end of the ultrasonic waveguide 1. The two are fixed by interposing a spacer member 50. 50
A and 50B each indicate a vent. One end of the ultrasonic waveguide 1 is provided with a sound collection guide part 51a, as in the case of the third embodiment described above (see FIG. 6), and an ultrasonic transducer 53 is attached to the end of the sound collection guide part 51a. There is. 1A and 2A each indicate the other end face as an ultrasonic wave reflecting means.

Even in this case, in addition to having the same functions and effects as the first embodiment described above, there is an advantage that the receiving sensitivity of reflected ultrasound waves can be particularly improved.

Here, regarding the ultrasonic waveguide 1 and the ultrasonic reflection member 2, the waveguide 1 may be a small cylinder and the reflection member 2 may be a large cylinder, as shown in FIG. Alternatively, as shown in FIG. 12, the waveguide 1 may have a cylindrical shape and the reflecting member 2 may have a concave cross section, with the concave portions facing the waveguide 1 and disposed at equal intervals as shown in the figure. In FIG. 12, the waveguide 1 may be in the form of a small cylindrical tube. Regarding the waveguide 1 and the reflecting member 2, three strip-shaped plates of the same shape are arranged at equal intervals as shown in FIG. Member 2.
2 may be used. Figure 14 is the 13th
A modification of the figure is shown.

The configuration shown in FIGS. 11 to 14 has the advantage that the sensitivity of the received signal can be significantly improved.

In addition, in each of the above embodiments, the case where the length of the waveguide 1 and the reflecting member 2 are equal is illustrated, but the present invention is not necessarily limited to this, and can be applied in substantially the same way to a case where the lengths are different. .

〔Effect of the invention〕

Since the present invention is configured and functions as described above, it is possible to measure the sound velocity of a medium to be measured with high accuracy regardless of the length of the waveguide, and therefore, the sound velocity of a medium to be measured can be, for example, a high-temperature fluid. Even with highly dangerous fluids, remote measurement is fully possible from a distance. Therefore, even if a normal ultrasonic transducer is used, sufficient durability can be ensured. To provide an ultrasonic sensor device that is easy to handle and can simplify the entire device because it can perform measurements with a single sonic transducer, has excellent durability, and is suitable for remote measurement. can do.

[Brief explanation of the drawing]

FIG. 1 is a partially omitted front view showing the first embodiment of the present invention, FIG. 2 is an explanatory diagram showing waveforms of transmitted waves and received waves obtained through experiments based on the configuration of FIG. 1, and FIG. The figure is a diagram showing the experimental results of Fig. 1, Fig. 4 is a chart showing the sound speed of water obtained based on the experimental results of Fig. 1, and Fig. 5 is a diagram showing the second example, with some parts omitted. 6 is a partially omitted front view showing the third embodiment, FIG. 7 is a sectional view taken along the arrow ■-■ line in FIG. 6, and FIG. 8 is a partially omitted front view showing the third embodiment. A front view with parts omitted; FIG. 9 is a cross-sectional view of a waveguide portion showing another embodiment;
FIG. 10 is an explanatory view showing the fifth embodiment, and FIGS. 11 to 14 are front views showing other embodiments of the waveguide and the reflecting member. 1... Ultrasonic waveguide, 2... Ultrasonic reflecting member, 3.4, 43.53... Ultrasonic transducer, IA. 2A...End face as ultrasonic reflecting means, 41B
. 42B...Notch part as ultrasonic wave reflecting means. Patent applicant Ken Ken Nakabachi (and 1 other person) Figure 1 Figure ε Figure 9 Figure 1O Figure 11 Figure 12 Figure 13 Figure 14

Claims (18)

[Claims] (1) An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member disposed at a certain distance from the ultrasonic waveguide, and an ultrasonic transmitter/receiver installed at one end of the ultrasonic waveguide. 1. An ultrasonic sensor device comprising: a waveguide, and an ultrasonic reflecting means provided at the other end of the ultrasonic waveguide. (2) The ultrasonic sensor device according to claim 1, wherein the ultrasonic waveguide and the ultrasonic reflecting member are a pair of elastic plates. (3) The ultrasonic sensor device according to claim 1, wherein the ultrasonic waveguide and the ultrasonic reflecting member are formed of a pair of round bar-shaped members. (4) The ultrasonic sensor device according to claim 1, wherein the ultrasonic waveguide and the ultrasonic reflecting member are formed by a pair of pipe-shaped members. (5) Claims 1, 2, 3, or 4, characterized in that the ultrasonic waveguide and the ultrasonic reflecting member are formed with the same length in the ultrasonic propagation direction. The ultrasonic sensor device described. (6) Claims 1, 2, 3, or 4, wherein the ultrasonic waveguide and the ultrasonic reflecting member are formed with different lengths in the ultrasonic propagation direction.
The ultrasonic sensor device described in . (7) The ultrasonic sensor device according to claim 1, wherein the ultrasonic transducer is mounted on a side surface of the ultrasonic waveguide. (8) The ultrasonic sensor device according to claim 1, wherein the ultrasonic transducer is mounted perpendicular to the center line of the ultrasonic waveguide. (9) The ultrasonic waveguide is formed by a plate-shaped member having a constant width, and the ultrasonic reflecting member is formed by two plates each disposed at equal distances from both sides of the ultrasonic waveguide. The ultrasonic sensor device according to claim 1, characterized in that it is formed of an ultrasonic reflecting plate. (10) The ultrasonic sensor device according to claim 1, wherein the ultrasonic waveguide and the ultrasonic reflecting member are formed of plate-like members having the same size. (11) The ultrasonic wave according to claim 9 or 10, wherein a surface of the ultrasonic wave reflecting member on the ultrasonic waveguide side is formed as a concave ultrasonic reflecting surface. sensor device. (12) The ultrasonic waveguide is formed of a small cylindrical member, and the ultrasonic reflecting member is at least one concave reflecting plate disposed at a position concentric with the ultrasonic waveguide. An ultrasonic sensor device according to claim 1, characterized in that: (13) The ultrasonic wave reflecting member is formed in a cylindrical shape, and the ultrasonic waveguide is formed of a round bar or a member similar thereto, and the ultrasonic wave guide is located on the center line of the ultrasonic reflecting member. The ultrasonic sensor device according to claim 1, characterized in that the ultrasonic sensor device is disposed in a. (14) The ultrasonic sensor device according to claim 13, wherein the ultrasonic waveguide is formed of a small cylindrical member. (15) The ultrasonic wave reflecting member according to claim 14 is characterized in that the ultrasonic wave reflecting member is at least one concave reflecting plate arranged on a concentric circle from the ultrasonic waveguide. Sonic sensor device. (16) An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member disposed a certain distance from the ultrasonic waveguide, and an ultrasonic transmitter/receiver installed at one end of the ultrasonic waveguide. a waveguide, an ultrasonic reflecting means is provided at the other end of the ultrasonic waveguide, a spacer is provided between each end of the ultrasonic waveguide and the ultrasonic reflecting member; An ultrasonic sensor device characterized in that a sound insulating member is interposed between the spacer and the ultrasonic waveguide and the ultrasonic reflecting member. (17) An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member provided at a certain distance from the ultrasonic waveguide, and an ultrasonic wave transmitter/receiver installed at one end of the ultrasonic waveguide. a spacer is disposed between both ends of the ultrasonic waveguide and the ultrasonic reflecting member, and each spacer has a sound insulator at each contact portion of the ultrasonic waveguide and the ultrasonic reflecting member. An ultrasonic sensor device comprising: an ultrasonic reflecting member provided on an ultrasonic waveguide located inside a spacer at each other end. (18) An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member provided at a certain distance from the ultrasonic waveguide, and an ultrasonic wave transmitter/receiver installed at one end of the ultrasonic waveguide. The tips of the other ends of the ultrasonic waveguide and the ultrasonic reflecting member are formed relatively sharply, and an ultrasonic reflecting means is provided at an appropriate position close to the tip of the ultrasonic waveguide. An ultrasonic sensor device characterized in that: