JPH0716977Y2 - Ultrasonic probe and ultrasonic flowmeter using the same - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe and an ultrasonic flowmeter using the ultrasonic probe.

[0002]

2. Description of the Related Art Conventionally, as a measuring device using ultrasonic waves, an ultrasonic quantity meter and an ultrasonic distance are widely known. As a measuring means of these measuring devices, ultrasonic waves are transmitted and received from an ultrasonic probe, and calculation is performed based on the difference in their propagation times to display measured values.

FIG. 6 shows a conventionally known ultrasonic flowmeter. In FIG. 6, reference numeral 20 indicates a measuring tube through which the substance to be measured passes, and reference numerals 21 and 22 indicate ultrasonic probes for transmitting and receiving ultrasonic waves, respectively. Also reference numeral 2
Reference numeral 3 and reference numeral 24 are cylindrical bodies on which the ultrasonic probes 21 and 22 are mounted. The ultrasonic probes 21 and 22 have a cylindrical body 23,
And 24 are mounted at a predetermined inclination angle θ toward the axis of the measuring tube 20, respectively.

The flow rate in the pipe is measured by alternately transmitting and receiving ultrasonic pulses in the A and B directions between the probes 21 and 22 with respect to the object to be measured in the pipe 20 and transmitting ultrasonic pulses. The measurement is performed by measuring the forward propagation time and the backward propagation time with respect to the direction and the flowing direction of the substance to be measured. Then, the flow rate V per unit time is calculated by obtaining the flow velocity V of the measured object from the difference between the respective propagation times and further using the cross-sectional area of the pipe 20.

[0005]

However, in such a conventional ultrasonic flowmeter, as shown in FIG. 7, the ultrasonic pulses emitted from the ultrasonic probes 21 and 22 have the original propagation paths A and B. In addition, there are propagation paths a and b which propagate from the attachment contact portions 25 and 26 of the ultrasonic probes 21 and 22 through the pipe wall of the pipe 20 and the like. Here, the propagation speed of the ultrasonic waves in the original propagation paths A and B is about 350 [m / S] when the object to be measured is air, whereas the propagation speed in the propagation paths a and b is steel pipes. In the case of, it is about 5000 [m / S]. The difference between these sound velocities occurs because the medium through which the ultrasonic waves pass has an inherent ultrasonic wave propagation velocity, and the pulse wave propagating through the paths a and b is the original path A. , B arrives at the ultrasonic probe on the receiving side earlier than the pulse wave propagating in B. Further, since the pulse waves propagating through the paths a and b have a plurality of paths and propagate through a plurality of parts, reflection at the boundary between the contact parts of the parts and this reverberation are superimposed. To be done. For this reason, the pulse has a remarkably long tail, and overlaps with the pulse wave of the route A that is originally desired as information. Therefore, there is an inconvenience that it is difficult to detect the received wave. Further, there is a disadvantage that a measurement error of the propagation time is generated, and thus the accuracy of the flow rate measurement itself is significantly reduced.

FIG. 8 shows received waveforms in each state in these conventional examples. FIG. 8A shows an original received wave propagating along the path A, and FIG. 8B shows an interfering wave propagating through the measuring tube. In general, the propagation time is measured at the zero-cross point, so enlarged views of that point are shown in FIGS. The phase relationship between the original received wave (solid line) and the interfering wave (dotted line) changes depending on conditions such as the propagation path length, the sound velocity of the propagation medium, and the flow velocity of the fluid to be measured. (C) shows the case where the interference wave has a maximum value of plus (+), and (d) shows the case where the interference wave has a maximum value of minus (-). In this case, in (c), the measurement point t'becomes later than the original reception time t with respect to the time axis, and is shifted to the right in the figure. Further, in (d), the measurement point t'becomes earlier than the original reception time t with respect to the time axis, and is shifted to the left in the figure. As a result of these, as shown in FIG. 9, an interfering wave is superposed on the normal received wave, which causes inconvenience in measuring the propagation time and lowering the measurement accuracy. On the other hand, the same situation has occurred in other measuring devices, for example, a reflection type ultrasonic distance measuring device equipped with a transmitting / receiving probe separately.

[0007]

SUMMARY OF THE INVENTION The object of the present invention is to improve the inconveniences of the conventional example, particularly to effectively eliminate the mixing of noise, and to improve the measurement accuracy, and an ultrasonic probe and an ultrasonic flow rate using the same. The purpose is to provide a total.

[0008]

According to the present invention, there is provided an ultrasonic probe having a vibrator holder having an ultrasonic vibrator at one end and a support member for supporting the vibrator holder. A configuration is adopted in which a vibration absorbing member is interposed between a vibrator holder and a supporting member included in the ultrasonic probe.

Further, according to the present invention, a pair of ultrasonic probes for flow rate measurement, which are arranged at a predetermined distance through the pipe, and the ultrasonic probe are attached and detached at a predetermined inclination angle with respect to the axis of the pipe. And a probe holder that is freely and hermetically mounted. Then, an ultrasonic probe having a vibrator holder and a support member for supporting the vibrator and having a vibration absorbing member between the vibrator holder and the support member is used. There is. These are intended to achieve the above-mentioned object.

[0010]

When the ultrasonic vibrator vibrates, the vibration wave (ultrasonic wave) propagates inside the vibrator holder and then propagates to the support member side. On the other hand, since the absorbing member is interposed between the supporting member and the oscillator holder, the ultrasonic component propagating to the supporting member side is effectively blocked by the action of the absorbing member.

[0011]

[First Embodiment] A first embodiment of the present invention will be described below with reference to FIG. In FIG. 1, reference numeral 20 indicates a pipe, and reference numeral 21 indicates a probe holder for an ultrasonic probe. The probe holder 21 has an opening 27 having one end opened on the inner wall of the pipe 20, and the pipe 2
They are arranged so as to face each other at a predetermined inclination angle on the axis 0.

On the other hand, the probe holder 21 is mounted with the entire probe including the vibrator holding member 1, the supporting member 2 and the control unit 8. Piping 20 of vibrator holding member 1
A vibrator 6 serving as an ultrasonic wave oscillation source is attached to one side end, and the center and the other end of the vibrator holding member 1 are arranged along the outer diameter of the vibrator holding member 1. Projected collar portions 1a and 1b are provided, respectively. Then, a flat ring-shaped tamper 5 made of an elastic member and O-rings 3 and 4 (vibration absorbing member) are provided at the corners of the shaft portion 1c surrounded by the flange portions 1a and 1b where the flange portions 1a and 1b intersect. Each is incorporated. Shaft part 1 incorporating these vibration absorbing members
The c is inserted into the inner diameter portion of the tubular support member 2. Then, the collar portion 2a of the supporting member having the vibrator holding member 1 mounted in this way is attached to the end portion of the probe holder 21 by the hook nut 3a.
It is screwed with 0 and sealed by the O-ring 28. Further, the transmission and reception of the signal to and from the ultrasonic transducer 6 is performed by the control unit 8 screwed and locked to the terminal end of the support member 2.
It is performed by a cable (not shown) connecting to the vibrator holding member 1.

Since the vibrator holding member 1 is incorporated by such a structure, the shaft portion 1c of the vibrator holding member 1 is assembled.
Are held in the inner diameter portion of the support member 2 with gaps at two positions in the longitudinal direction, which are appropriately separated, via O-rings 3 and 4. For this reason, the vibrator holding member 1 has a degree of freedom only in the longitudinal direction of the axis (the vibration direction of the ultrasonic vibrator). Further, a damper 5 is provided at a contact point between the flange portion 1a of the vibrator holding member and the support member 2 in the longitudinal direction. As a result, the vibrator holding member 1 and the support member 2 can be insulated.

Next, the operation of the above embodiment will be described. In FIG. 1, the ultrasonic vibrator 6 receives a signal from the control unit 8 via a cable (not shown) and starts ultrasonic vibration. Then, the ultrasonic wave 9 generated thereby passes through the measurement object through the opening 27 of the measuring tube. Then, the ultrasonic wave is transmitted and received between the ultrasonic transducer (not shown) similar to that shown in FIG. 1 which is arranged on the other side of the pipe 20 coaxially with each other with a predetermined inclination angle. Be seen. At this time, the vibrator holding member 1 that holds the ultrasonic vibrator 6 also vibrates together with the ultrasonic vibrator 6. Since this ultrasonic vibration is the same longitudinal vibration as the longitudinal direction of the axis of the vibrator holding member 1, the vibrator holding member 1 has two elastic members in the longitudinal direction with the shaft portion 1c at the center of the holding member at a predetermined interval. Since they are held with a gap in the inner diameter portion of the support member 2 through the O-rings 3 and 4, the flexible movement can be performed following the longitudinal direction of the axis (the ultrasonic vibration direction).

FIG. 5 also shows the measurement results of the received waves measured on the receiving side when transmitting and receiving under the same conditions as in the conventional example.
According to this, it can be seen that the disturbing wave portion is significantly reduced.

[0016]

[Second Embodiment] FIG. 2 shows a second embodiment. In the second embodiment shown in FIG. 2, the end portion of the vibrator holding member 1 described above is extended and directly screwed and locked to the case 10 of the control unit 8. Therefore, the support member 2 in which the vibrator holding member 1 and the probe holder 21 are in direct contact with the pipe 20
Therefore, the ultrasonic transducer 6 mounted on the transducer holding member 1 can be isolated from an interfering wave using the pipe 20 as a propagation medium. The other structure is similar to that of the first embodiment.

[0017]

[Third Embodiment] FIGS. 3 to 4 show a third embodiment. In the third embodiment shown in FIGS. 3 to 4, the vibrator holding member 1 and the supporting member 2 for holding the vibrator holding member 1 in a penetrating manner are provided.
To the mating portion with the groove portions 1
3a, 14, 14a are provided. Then, steel balls 11, 11a, 12, 12a are arranged in the groove portions, respectively. Therefore, the vibrator holding member 1 provided with the linear bearing-shaped sliding mechanism portion in the gap with the support member can freely follow the axial longitudinal direction (ultrasonic vibration direction). On the other hand, this vibrator holding member 1
By mounting the spring 13 made of an elastic member or the like through the space 7 at the end portion of the, a flexible movement corresponding to the movement of the vibrator holding member 1 in the longitudinal direction of the axis (ultrasonic vibration direction) can be achieved. Has been done.

In each of the above-mentioned embodiments, the ultrasonic probe is an ultrasonic flowmeter, and the ultrasonic probe is an ultrasonic rangefinder. It may be.

[0019]

Since the present invention is constructed and functions as described above, it is possible to prevent the vibration of the vibrator holding member, which resonates together with the ultrasonic vibrator, from being transmitted from the support member to the outside. It is possible to effectively block the propagation of ultrasonic vibrations to the pipe in contact with the ultrasonic probe, and to block the interfering wave propagating inside the pipe wall at the time of reception by the ultrasonic probe portion. Therefore, it is possible to prevent the interference wave from being superimposed. Therefore, in the flow rate measurement, simultaneous reception of noise can be effectively prevented, and thus stable and highly accurate flow rate measurement in which no interfering wave is superimposed can be performed. In addition, even when acoustic coupling occurs between the inside of the holder and the ultrasonic probe due to the accumulation of dust or the like in the gap between the ultrasonic probe mounted inside the probe holder, the vibration of the ultrasonic probe Since the child holding member is kept insulated from the outside, it is possible to prevent the influence of interfering waves, and also in this respect, it is possible to remarkably improve the accuracy, and a practical ultrasonic probe and an unprecedented practical ultrasonic probe. An ultrasonic flowmeter using the can be provided.

[Brief description of drawings]

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

FIG. 2 is a cross sectional view showing a second embodiment.

FIG. 3 is a vertical sectional view showing a third embodiment.

4 is a cross-sectional view taken along the line A-A ′ in FIG.

5 is a diagram showing a state of a received wave in the embodiment of FIG.

6 to 7 are partially cut explanatory views showing a conventional example.

FIG. 8 is an explanatory diagram showing an interference example of an interfering wave with respect to a zero cross point of a received wave in a conventional example.

FIG. 9 is a diagram showing a state of a received wave in a conventional example.

[Explanation of symbols]

 1 Vibrator Holding Member 2 Support Member 3 Elastic Member 4 Elastic Member 6 Ultrasonic Transducer 20 Piping 21 Flobe Holder

Claims (3)

[Scope of utility model registration request] 1. An ultrasonic probe comprising a vibrator holder having an ultrasonic vibrator at one end, and a support member for supporting the vibrator holder, wherein the vibrator holder and the support member are provided. An ultrasonic probe having a vibration absorbing member interposed therebetween. 2. The ultrasonic probe according to claim 1, wherein the vibration absorbing member has at least a vibration absorbing function in a direction along a vibration direction of the ultrasonic transducer. 3. A pair of ultrasonic probes for flow rate measurement, which are arranged at a predetermined distance through a pipe, and the ultrasonic probe is detachable at a predetermined inclination angle with respect to the axis of the pipe. A probe holder mounted in a sealed state, the ultrasonic probe having a vibrator holder and a support member supporting the vibrator holder, and a vibration absorbing member provided between the vibrator holder and the support member. An ultrasonic flow meter characterized by using one.