JPH0554898B2 - - Google Patents

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 measuring 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, and these are integrated with a bonding material, so there is an upper limit to the operating temperature (approximately
400 [°C]), making it nearly impossible to regularly and continuously measure temperatures between 500 and 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 such conventional examples, and particularly targets fluids and soft materials, even if they are harmful or constantly exposed to high temperatures. We have developed an ultrasonic sensor device that can remotely measure the speed of sound of an object and its changes with high precision, and thereby the temperature and viscosity of the object and its changes with high precision. to provide
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. The present invention attempts to achieve the above object by adopting a configuration in which an ultrasonic wave transducer and an ultrasonic waveguide are provided, and an ultrasonic reflecting member is provided at the other end of the ultrasonic waveguide.

[First Embodiment of the Invention] The first embodiment of the present invention will be described below with reference to FIGS. 1 to 4.
This will be explained based on the diagram.

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 D from each other and the ultrasonic waves An ultrasonic reflecting member (hereinafter simply referred to as a "reflecting member") formed in the same shape as the waveguide 1
) 2, and an ultrasonic transducer 3 attached to one end of the ultrasonic waveguide 1.

A waveguide 1 and a reflecting member 2 provided opposite thereto
are made of stainless steel and have the same length in this embodiment. This waveguide 1 and reflecting member 2
The other end is arranged within the medium 5 to be measured as shown in the figure.

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

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

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 in contact with a liquid or a fixed object, the waveguide 1
A portion of the sound wave energy propagating therein 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 an ultrasonic wave is incident on the waveguide 1 from the ultrasonic transducer 3, the wave propagates within the waveguide 1 toward the medium 5 to be measured. In this case, of the speed at which the ultrasonic wave propagates through the waveguide 1, the phase speed is
Let V _p be the group velocity, and V _g be the group velocity. When the waveguide 1 is in contact with the medium 5 to be measured and the sound velocity V of the medium 5 to be measured at this time is smaller than the phase velocity V _p of the waveguide 1, the waveguide 1
A portion of the ultrasonic energy propagating therein is radiated into the medium 5 to be measured. The radiation angle θ at this time is determined by the following equation.

θ=sin ^-1 (V/V _p ) The ultrasonic wave that entered the medium 5 to be measured reaches the reflecting member 2, and the waves propagating along the reflecting member 2 and
Some waves 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 steps, the path in the medium to be measured will take N steps (N=
The arrival time of the received waves (1, 2, 3, ...) is t _N [(2L-ND _tao θ)/V _g ] + [ND/V _cps θ] + τ ₁ + τ ₂ ... Here, τ ₁ , τ ₂ is the fixed delay amount during transmission and reception.

Next, finding the difference in the case of N=2 and 4, Δt=2D [(1/V _cps θ) − (tanθ/V _g )]... Therefore, the sound velocity V of the medium to be measured is as follows. Determined from the formula.

(4D ² +V _g ² Δt ² )V ⁴ − (8D ² V _p V _g +V _p ² V _g ² Δt ² )V ² +4D ² V _p ² V _g ² =0... Therefore, if we measure Δt, , known D, V _g , V _p
The sound velocity V of the medium to be measured 5 can be determined from the formula.

These series of calculations are performed in a calculation section (not shown) of the main body that has a display function.

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

As the waveguide 1 and the reflecting member 2, the plate thickness is
A 0.95 [mm] 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
It was fixed at 31.5 degrees so that the S ₀ mode plate wave was guided. Tap water (21 [℃]) as the measuring medium
was used. Therefore, in this case, the group velocity of the guided wave
V _g and phase velocity V _p can be considered to be approximately equal to the S ₀ mode even within the medium 5 to be measured (IAViktrov. "Rayleigh and Lamb Waves"
P.117).

The applied electric pulse was a two-sine wave of 200 [V _pp ]. 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 and 4 indicate waves whose underwater paths are 2 strokes and 4 strokes, respectively. *mark is N
2 shows a received waveform of a wave in which the wave of =2 has made one round trip through the waveguide 1. In this example, Δt=75.1 [μs].
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 becomes V _g ≈5200 [m/s]. In addition, the phase velocity can be calculated from the acoustic velocity of the acrylic material, 2720 [m/s], and the set incident angle of the variable angle probe, 31.5°C, and V _p ≒ 5300.
[m/s].

On the other hand, the relationship between the waveguide 1 and the reflecting member 2 is
The results confirmed by actual measurement by changing the interval D are shown in the third section.
As shown in the figure. From this, it was possible to obtain Δt/D=1.26 [μs/mm]. The sound speed of water can be calculated from the formula using V _g and V _p found earlier. The results are shown in FIG. The temperature was measured at three points. Result is,
This agrees very well with generally published values.

In this way, according to the first embodiment, the medium to be measured 5 can be
The sound velocity V of the medium to be measured can be found by simply detecting the reception time difference between the second wave and the fourth wave of the received waves. Since the length of the reflecting member 2 is irrelevant, it is possible to remotely measure high-temperature fluids or highly dangerous fluids, for example.
Therefore, even if a normal ultrasonic transducer 3 is used, there is an 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 as a remote measurement, which is easy to handle.

In addition, 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, it is possible to simultaneously detect the liquid level of the medium 5 to be measured. There are also advantages.

Furthermore, in the first embodiment, the waveguide is formed of a plate-like member, but other members,
For example, the waveguide may be formed of a round bar member, a suitable wire member, a pipe-shaped member, or the like.

[Second Embodiment] 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 consists of a waveguide 1 and a reflecting member 2, which are made of stainless steel plate members, and which are arranged at a certain distance D.
an ultrasonic transducer 3 attached to one end of the
A spacer 10 is provided between the waveguide 1 and one end of the reflecting member 2.

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 is a block 10 made of an insulating material.
A and sound insulating members 10B fixed to both ends of the block 10A. As the sound insulation member 10B, a member having an acoustic impedance significantly different from the acoustic impedance of the waveguide 1 is used. Also, this spacer 10
is sandwiched 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 . Further, a sound insulating member 12 is provided on the outside of the reflecting member 2. and,
The above-described transducer 3, waveguide 1, reflection member 2, and spacer 10 are all clamped by the clamp mechanism 15 via the sound absorbing member 11 and the sound insulating member 12, and the set screw 15A, which the clamp mechanism 15 has, 15B, it is fixed as shown in FIG.

In this case, the sound insulating member 12 of the spacer 10 is generally made of a heat insulating material such as asbestos or foamed plastic that has sound insulating properties. The waveguide 1 and reflective member 2 of this foamed plastic
The difference in acoustic impedance for
It has become 10,000 times bigger. For this reason, block 10
The ultrasonic energy propagating to A is almost negligible.

Even in this case, the same working effect as in the first embodiment described above is obtained, and the mutual dimensions of the waveguide 1 and the reflecting member 2 are It has the advantage that it can be maintained effectively.

[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 a circular cross section are provided, and sound collecting 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. Spacer 4
The structure is equipped with 5. This spacer 4
5 has sound insulating members 45A and 45B at the contact portions with the waveguide 1 and the reflecting member 2.

The other ends of the waveguide 1 and the reflecting member 2 are formed relatively sharply, and notches 41B and 42B as ultrasonic reflecting means are formed on the waveguide 1 and the reflecting member 2 close to the sharp ends 41A and 42A. 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. This third embodiment is suitable for measuring the sound velocity of a solid object, which is a soft member. Other configurations and effects are described in the first section above.
It is substantially the same as the embodiment.

In each of the above embodiments, the spacers 10 and 45 are provided at one end of the waveguide 1 and the reflecting member 2, or are not used, but these spacers do not interfere with the propagation of leaky waves. As long as it has a certain range or structure, it may be installed at multiple locations, such as at the tip (other end).

[Fourth Example] Next, a fourth example will be described 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. This spacer member 20 is connected to the waveguide 1
Sound insulating members 20A and 20B are provided on the reflecting member 2 portion, 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, the waveguide 1 and the reflecting member 2
There is an advantage that minute vibrations at the other end 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 extremely high efficiency in transferring sound wave energy from one side to the other due to their mutual lens action. Since it has the effect of increasing the speed of sound, it is effective when measuring the speed of sound in 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, a rod-shaped ultrasonic waveguide 1 is disposed on the center line of the reflecting member 2, and a spacer member 50 made of a sound insulating material is inserted at one end of the rod-shaped ultrasonic waveguide 2 to fix both. be. 50A and 50B each indicate a vent. One end of the ultrasonic waveguide 1 is provided with a sound collecting guide part 51a, as in the case of the third embodiment described above (see FIG. 6), and an ultrasonic transducer 53 is attached to that end. There is. 1A, 2
A indicates the end face of the other end serving as an ultrasonic 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 reflecting member 2, as shown in FIG.
may be a small cylinder and the reflecting member 2 may be a large cylinder. Alternatively, as shown in FIG. 12, the waveguide 1 may be cylindrical and the reflecting member 2 may be concave in cross section, with the concave portions disposed at equal intervals toward the waveguide 1 as shown in the figure. In FIG. 12, the waveguide 1 may be in the shape 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. FIG. 14 shows a modification of FIG. 13, which may be configured to be used as members 2, 2.

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,
According to this method, the sound speed of a medium to be measured can be measured with high precision regardless of the length of the waveguide, and therefore even if the medium to be measured is a high-temperature fluid or a highly dangerous fluid, it can be measured from a distance. Remote measurement is fully possible, and even if a normal ultrasonic transducer is used, sufficient durability can be ensured.Measurements can be made with a single ultrasonic transducer, so it is easy to handle. It is possible to provide an ultrasonic sensor device that is easy to use and has good durability, which is unprecedented in that it is easy to use and can simplify the entire device, and is suitable for remote measurement.

[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 in Figure 1, and Figure 4.
The figure is a diagram showing the sound speed of water obtained based on the experimental results shown in Figure 1, Figure 5 is a partially omitted front view showing the second embodiment, and Figure 6 is a partial diagram showing the third embodiment. 7 is a sectional view taken along the arrow-line in FIG. 6, FIG. 8 is a partially omitted front view showing the fourth embodiment, and FIG. 9 is a guide 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, 1A,
2A... End face as ultrasonic reflecting means, 41B,
42B... Notch portion as ultrasonic wave reflecting means.

Claims (1)

[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 wave reflecting member provided at one end of the ultrasonic waveguide. 1. An ultrasonic sensor device comprising an ultrasonic transducer and an ultrasonic waveguide, and further comprising an ultrasonic reflecting means 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 by 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. Claim 1, wherein the ultrasonic waveguide and the ultrasonic reflecting member are formed with the same length in the ultrasonic propagation direction.
The ultrasonic sensor device according to item 2, 3 or 4. 6. The ultrasonic waveguide and the ultrasonic reflecting member according to claim 1, 2, 3 or 4, wherein the ultrasonic waveguide and the ultrasonic reflecting member are formed with different lengths in the ultrasonic propagation direction. Ultrasonic sensor device. 7. The ultrasonic sensor device according to claim 1, wherein the ultrasonic transducer is attached to 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 ultrasonic reflecting members separately 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 a 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 sensor device according to claim 9 or 10, wherein the ultrasonic waveguide side surface of the ultrasonic reflecting member is formed into a concave ultrasonic reflecting surface. 12. The ultrasonic waveguide is formed by a small cylindrical member, and the ultrasonic reflecting member is at least one concave reflecting plate disposed at a position on a circle from the ultrasonic waveguide. An ultrasonic sensor device according to claim 1. 13 The ultrasonic wave reflecting member is formed in a cylindrical shape, the ultrasonic waveguide is formed of a round bar or a member similar thereto, and the ultrasonic waveguide is disposed on the center line of the ultrasonic reflecting member. The ultrasonic sensor device according to claim 1, characterized in that: 14. The ultrasonic sensor device according to claim 13, wherein the ultrasonic waveguide is formed of a small cylindrical member. 15. The ultrasonic sensor device according to claim 14, wherein the ultrasonic reflecting member is at least one concave reflecting plate disposed on a concentric circle from the ultrasonic waveguide. . 16 An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member disposed at a certain distance from the ultrasonic waveguide, and an ultrasonic transducer installed at one end of the ultrasonic 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, and the spacer and An ultrasonic sensor device characterized in that a sound insulating member is interposed between the ultrasonic waveguide and the ultrasonic reflecting member. 17 An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member arranged at a certain distance from the ultrasonic waveguide, and an ultrasonic transducer installed at one end of the ultrasonic waveguide. a spacer is disposed between the ends of the ultrasonic waveguide and the ultrasonic reflecting member, and a sound insulating member is provided at each contact portion of the ultrasonic waveguide and the ultrasonic reflecting member of each spacer. An ultrasonic sensor device characterized in that an ultrasonic reflecting member is provided on the ultrasonic waveguide located inside the spacer at each other end. 18 An ultrasonic waveguide made of an elastic member, an ultrasonic reflecting member arranged at a certain distance from the ultrasonic waveguide, and an ultrasonic transducer 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 featuring: