JPH0394109A - Ultrasonic measuring device - Google Patents

Abstract

PURPOSE:To reduce the influence of temperature and humidity exerted on an ultrasonic propagation path and to improve the measuring accuracy for a distance to an object body and its thickness by an ultrasonic wave by providing a reflecting body for shielding a part of an ultrasonic beam in a prescribed distance in front of a probe. CONSTITUTION:In a position of a prescribed distance LK in front of an ultrasonic probe 2, an ultrasonic reflecting body 7 is placed so as to shield a part of an ultrasonic beam. An ultrasonic wave US emitted from a transmitting probe 2T is reflected by an object body 6, and also, a part of the ultrasonic wave UK is reflected by the reflecting body 7 and received by a receiving probe 2R. The received ultrasonic wave passes through a receiving circuit 3 and processed by time detecting circuits (4S, 4K) and an ultrasonic propagation time is derived. Subsequently, an ultrasonic propagation time TS to the object body 6 and an ultrasonic propagation time TK to the reflecting body 7 are derived by the circuit 4S and the circuit 4K, respectively. The propagation time TS, TK derived by the circuit 4S, 4K is sent to a distance arithmetic circuit 5 and a value of a distance LS calculated, and since the distance LK between the probe 2 and the reflecting body 7 is constant, a result of measurement can be obtained without the influence of a sound velocity controlled by a temperature variation.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention relates to distance measurement using ultrasonic waves, object shape measurement, and improvement of dimension measurement devices. For example, various materials used in the industrial field Ultrasonic waves are radiated through the air from one side of the material, and the length of time it takes to be reflected by the material surface and return
The distance between Ll7 and the material can be known. Therefore, the shape of the material can be measured from the 2p@, and dimensions such as thickness can be measured by irradiating from both sides. Also, 1 of the valley rod parts? It is also used to measure porosity.

rConventional technology] The technology of injecting ultrasonic waves into solids such as metals to inspect the presence or absence of defects inside the solid is called ultrasonic flaw detection, and is widely used as an effective means of product inspection and maintenance inspection. . Furthermore, devices that emit ultrasonic waves into the air or into liquids to detect the presence of objects or measure the distance to objects have already been put into practical use.

Figure 7 is an explanatory diagram of a method for detecting the presence or absence of an object in the air and the distance to the object using ultrasonic waves. (1) is a transmitting circuit, (2T) is an ultrasonic transmitting probe, (2R) The supercombined wave reception probe is completed, and (3) is Buddha reception 1! ' 1 path, (4) is a time detection circuit, (5) is a distance calculation circuit, (6) is an object to be measured, and U8 is an ultrasonic wave propagating in the air,
I. 、． ．． indicates the distance between the ultrasonic probe and the object to be measured. Now, in response to the transmitted electric pulse from the transmitting circuit (1), the ultrasonic wave U is sent from the ultrasonic transmitting probe (2 pieces) to the inside of the tube.
．． is transmitted, the ultrasonic waves reach a total of i1111 target objects (6
The ultrasonic waves reflected from the surface of After that, the time detection circuit (4) detects the ultra 1'9 wave 4t<travel time'1'5 to the target object (6), and the distance calculation circuit (5) calculates the ultrasonic propagation time and ultrasonic wave. The distance is calculated from the speed of sound and output.

In Fig. 7, the case where the ultrasonic transmitting probe and the ultrasonic receiving probe are separated is described, but as shown in Z5 of Fig. 8, the ultrasonic transmitting transducer and the receiving probe are separated. Some devices are integrated with a vibrator, and the operation is exactly the same in that case.

In the example explained below, the ultrasonic velocity in the air is
, if the ultrasonic propagation time from the time when the ultrasonic probe transmits the ultrasonic wave until it is reflected by the object to be measured and returns is Tq, then from the ultrasonic probe (2) to the object to be measured (6) The distances I and q can be calculated using the following formula.

LS-(VA-T8)/2 --- (t) As can be seen from the above equation, the measurement accuracy of the distance Lq obtained in this way depends on the fluctuation of the ultrasonic velocity and the propagation time of the Mi sound wave. ′■゛One of these depends on the measurement error of 8.
I! 7 interval '1', total Δl1th + '1 degree is 迭f1; same contraction (1), receiving circuit (3), time detection circuit (4),
Determined by the signal 3 processing in the distance calculation circuit (5) + hK
It is possible to ensure a fairly high degree of accuracy in the close-up technique. On the other hand, the sound velocity VA of ultrasonic waves is greatly influenced by the environmental conditions within the ultrasound propagation path, and among these, fluctuations due to temperature are most likely to occur. The temperature characteristics of this ultrasonic sound velocity ■4 are given by equation (2), ? ``The temperature of the ultrasonic propagation edge path at i distance 1,...s 1 measurement 1t!7 is 20℃
If it is close, the rate of change is approximately 0.18%/'
It becomes C.

v,=v. (1+1Vo3)”2 −−−−−−−
(2) Here ■. is the ultrasonic sound velocity in the air at O0C, and T is the temperature in the air (°C) at the time of measurement.

[Problem to be solved by the invention 1 If the measurement distance 1, s is about 50 mm, the temperature 'F
If it changes by 1°C between 20°C and 21°C, the tone series VA changes by 0.18% as shown in -12, and as a result, the distance L5 becomes 50X 0. 001g=0. 09mm
It's going to change. Generally, when measuring the thickness of a material, a roughness of several tens of micrometers is required, so a change of even 1°C is not allowed (7). In particular, when the object to be measured is a high-temperature object, the effect on the degree of lagoon in the air is significant, making it difficult to ensure accuracy when measuring distance using ultrasonic waves.

The above description has been about measurement inside a liquid, but if there is a temperature change in a liquid, the ultrasonic sound speed will also fluctuate, making it difficult to measure distances with high precision using ultrasonic waves.

This invention was made in order to solve this problem, and the present invention addresses the environment in the ultrasonic propagation path, such as temperature and humidity, which are factors that change the speed of ultrasonic waves in the air or in a liquid in an ultrasonic measuring device. The influence of the conditions is reduced, and the distance to the target object by ultrasonic waves is 21 and P'/. The objective is to improve the measured viscosity.

[Means for Solving the Problems] The ultrasonic measuring device according to the present invention includes an ultrasonic reflector that is provided so as to block a part of the ultrasonic beam at a certain distance in front of the measuring ultrasonic probe. The ultrasonic propagation time and distance measured between the measurement ultrasonic probe and the ultrasonic reflector, and the ultrasonic propagation time obtained between the measurement ultrasonic probe and the target object (8). The distance from the measurement ultrasonic probe to the target object can be calculated using this method.

In addition, in the ultrasonic measuring device according to another invention of this fourth invention, a temperature detector is installed in the propagation path of the ultrasonic beam in the air or in the liquid between the measuring ultrasonic probe and the object to be measured. 31 Using the ultrasonic propagation time obtained between the measurement ultrasonic probe and the object to be measured and the temperature in the air or liquid obtained by the temperature detector, This method calculates the distance to the object to be measured.

Furthermore, an ultrasonic measuring device according to another aspect of the present invention has an ultrasonic transducer for calibration in addition to the ultrasonic transducer for measurement in the ultrasonic probe, and the ultrasonic transducer for calibration has a An ultrasonic reflector is provided to block the ultrasonic beam at a certain distance from The distance from the measuring ultrasonic transducer to the target object is calculated using the ultrasonic propagation time obtained between the transducer and the target object.

[Operation] In this invention. An ultrasonic reflector is placed at a certain distance from the measurement ultrasonic probe so as to block a portion of the ultrasonic beam, and the ultrasonic propagation time determined by the measurement ultrasonic probe is By using the ultrasonic propagation time and the distance between the measuring ultrasonic probe and the ultrasonic reflector when calculating the distance, changes in the environmental conditions of the ultrasonic propagation path are always reflected. As a result, the accuracy of measured values can be improved.

In another invention of the present invention, a temperature detector is disposed in the propagation path of the ultrasonic beam in the air or in a liquid between the measurement ultrasonic probe and the object to be measured, and the measurement ultrasonic probe When calculating the distance from the obtained ultrasonic propagation time, L
By taking into account the temperature obtained by the temperature detector described above, changes in the environmental temperature on the ultrasonic propagation time path are always reflected, and as a result, the accuracy of the measured value can be improved.

Furthermore, in another invention of the present invention, an ultra;:r1 wave reflector is installed at a constant distance {i'/ position in front of the calibration ultrasonic transducer to block the ultrasonic beam l. When calculating the distance from the ultrasonic propagation time obtained from the measurement ultrasonic vibration Jφ, use the ultrasonic propagation time obtained between the calibration ultrasonic transducer and the ultrasonic reflector and the distance between them. By doing so, changes in the environmental conditions of the ultrasonic propagation path are always reflected, and as a result, the accuracy of the measured values can be improved by -1.

[Example] Figure 1 shows an example according to this invention.
In this figure, (1), (2T), (2R), (3
), (4), (5) and (6) are the same as in Figure 7,
(7) is an ultrasonic repellent that reflects a part of the ultrasonic beam emitted from the measurement ultrasonic transmission probes (2 units), U8 is the measurement ultrasonic transmission/reception probe (2T), (2R ) and the ultrasonic reflector (7), and LK is the distance between them.

Currently, the measurement ultrasonic transmitting probes (2) have the above (1)
1) Similar to FIG. 7, electric pulses are supplied from the transmitting circuit (1) and ultrasonic waves U5 and UK are generated. The ultrasonic wave U8 propagated in the air is reflected by the target object (6), and the ultrasonic wave U8 is
After being reflected by the ultrasonic reflector (7) placed opposite to it, it is received by the measuring ultrasonic reception probe (2R). The ultrasonic waves received by the measuring ultrasonic receiving probe (2R) are converted into electrical signals, sent to the receiving circuit (3), processed by the time detection circuit (4), and processed by the ultrasonic wave transmission. Time is required. In this invention, 1. It is equipped with two time detection circuits, and the first time detection circuit (4S) detects the target object (
6), and the second time detection circuit (4K) detects the ultrasonic propagation time TK between the ultrasonic reflector (7) and the ultrasonic wave reflector (7). Here, the ultrasonic transmitting and receiving probe (
Since the distance LK between 2) and the ultrasonic reflector (7) is a known constant value, the sound velocity VK in the propagation path of the ultrasonic wave UK is determined by the following equation (3).

VK-2 LK/TK ・・・・・・・・・
(3)-1 It is thought that V1 obtained from the two equations is almost equal to the sound velocity in the propagation path of the ultrasonic wave U8, and by using this value in place of (+) in equation (I2), Measurement i! 1 distance is calculated by the following formula.

L. 1 (L.・T.)/'FK ・・・・・・・・・
(4) Therefore, time detection circuit (4S), (4K)
The ultrasonic propagation times Ts and TK obtained in
Li L. You can know the 41fj. In equation (4), +-K is constant and “I' s, I.K is propagation 1
Since it is time and does not include the speed of sound, which depends on temperature changes, it is always 1: L'1 degree a'5 L' 3
1'Ill'lL'i result can be obtained.

In the embodiment shown in Fig. 1 of 2 below, the case where the ultrasonic transmitting probe and the ultrasonic receiving probe are separated as in Fig. 3 was described, but both are connected to the body. In some cases, the operation is exactly the same.

FIG. 2 shows the relationship between the received ultrasonic waveform and the ultrasonic propagation time in the embodiment of FIG. 1 according to the present invention.
In (a) of the figure, T is a transmission pulse UK is a reflected echo from the ultrasonic reflector (7), and U8 is a reflected echo from the target object (6). In addition, (l) in the figure is the reflected echo UK.
(c) is a detection gate for extracting the reflected echo U9. In the time detection circuits (4K) and (43) in the embodiment of FIG. 1, reflected echoes are extracted by detection gates as shown in FIG. By calculating the ultrasonic propagation time TK and ′
I'5 can be obtained. In Fig. 1, the target object (
6), by arranging the measurement river Mir'+' wave probe J'- to face both sides of the target object (6),
The same can be applied to the case of measuring the thickness of the target object (6).

FIG. 3 shows another embodiment according to the present invention, in which (1), (2T), (2R), (
3), (4), (5), and (6) are the same as in Fig. 7, and (8) is placed in the propagation path of the ultrasound beam emitted from the measurement ultrasound transmission probe (2T). This is the temperature detection function.

Now, the measurement ultrasonic transmitting probe (2T) has the seventh
As shown in the figure, electric pulses from the transmitting circuit (1) are supplied (I3) and an ultrasonic wave U is generated. The ultrasonic wave U8 propagated through the diaphragm is reflected by the object to be measured (6) and then received by the measurement ultrasonic receiving probe (2R). The ultrasonic wave received by the measuring ultrasonic receiving probe (2R) is converted into an electrical signal, sent to the receiving circuit (3), and then processed by the time detection circuit (4) to determine the ultrasonic propagation time 'r5. is required.

Now, substituting equation (2) into equation (1) yields equation 7B7.

L, q=V.・'l'. (I l- 'I' /2
73) '''/2... (5) Therefore, the ultrasonic propagation time T8 obtained by the time detection circuit (4) and the temperature T obtained by the temperature detector (8) are sent to the distance calculation circuit (5). , the value of distance Lq can be found using the above equation (5). In equation (5), V is a - constant value and 'rs is the propagation time, which does not include the speed of sound that is affected by temperature changes. Therefore, it is possible to always obtain measurement results with a high ifJ degree.

In the example shown in Figure 3 of 12 below, we have described the case where the ultrasonic transmitting probe and the ultrasonic receiving probe are separated, similar to the seventh factor, but both ministries (15) Sometimes they are integrated, and in that case the operation is exactly the same.

FIG. 4 shows the relationship between the received ultrasonic waveform and the ultrasonic propagation time in the embodiment of FIG. 3 according to the present invention.
In (a), Tp is a transmission pulse, U. ．． is a reflected echo from the object to be measured (6).

Further, (b) in the figure is a detection gate for taking out the reflected echo U8. The time detection circuit in the embodiment of FIG.
In 4), the ultrasonic propagation time T8 can be obtained by extracting the reflected echo by a detection gate as shown in the fourth factor (h) and calculating the time between it and the transmitted pulse, for example.

In addition, in Fig. 3, a means for measuring the distance to the object to be measured (6) is explained, and the measurement ultrasonic probes are placed so as to face both sides of the object to be measured (6). This can be similarly applied to the case of measuring the thickness of the object to be measured (6).

FIG. 5 shows still another embodiment of the present invention, in which (1), (2), (3),
(4), (l6) (51 (6) is the same as in Figure 8, (7) is an ultrasonic reflector that reflects the ultrasonic beam emitted from the calibration ultrasonic transducer ZX, and U1 is the calibration The ultrasonic wave propagating in the air between the ultrasonic transducer Z8 and the ultrasonic reflector (7), LK is the distance therebetween.

Now, the measuring ultrasonic transducer Zq is supplied with electric pulses from the transmitter circuit (1) as in FIG. 8 above, and the ultrasonic wave U
8 is generated, and ultrasonic waves UK/IE are also generated in the calibration ultrasonic transducer ZK by electric pulses from the transmitting circuit (1).

Ultrasonic waves propagated through the diastole.゛゜? The wave U9 is reflected by the target object (6) and becomes super,'X1;. After the waves Ux are reflected by the ultrasonic reflectors (7) arranged opposite to each other, the waves Ux are reflected by the ultrasonic transducers 2. ．． Received at 2K. Ultra f for measurement and calibration
The ultra 1゜'1゛ wave received by the i-wave transducer is converted into an air signal, sent to the receiving circuit (3), and then processed by the time detection circuit (4) to determine the ultrasonic propagation time. It will be done. In this invention, two time detection circuits are provided, and the ultrasonic propagation time T9 between the first time detection circuit (4S) and the target object (6) is determined by the second time detection circuit (4K). )
Then, the ultrasonic propagation time T between the ultrasonic wave reflector (7) and the ultrasonic wave reflector (7) is detected. Here, since the distance LX between the calibration ultrasonic transducer zK and the ultrasonic reflector (7) is a known constant value, the sound velocity VK in the propagation path of the ultrasonic wave U8 is determined by the above equation (3). Desired.

It is considered that ■, obtained by equation (3), is approximately equal to the sound speed in the propagation path of the ultrasonic wave Us, and this value is calculated as VA in equation (1).
By substituting , the measured distance to the target object is calculated using the above-mentioned equation (4).

Therefore, the ultrasonic propagation times Ts and TK obtained by the time detection circuits (4S) and (4K) are sent to the distance calculation circuit (5), and the value of distance I78 is calculated using the above equations (3) and (4). You can know. In equation (4), LK is a constant value, 5 is the propagation time, and 'l' is the propagation time, which does not include the speed of sound, which is greatly affected by temperature changes, so it is possible to always obtain highly accurate measurement results. .

FIG. 6 shows the relationship between the received ultrasonic waveform and the ultrasonic propagation time in the embodiment of FIG. 5 according to the present invention.
In (a) of the figure, T is the transmitted pulse, UK is the reflected echo from the ultrasonic reflector (7), and U5 is the reflected echo from the object (6). In addition, (b)
The detection gate (c) for taking out the reflected echo Uk is a detection gate for taking out the reflected echo U8. In the time detection circuits (4K) and (4S) in the embodiment of FIG. 1, reflected echoes are extracted by detection gates as shown in FIG. By calculating the ultrasonic propagation time TX
and Tq can be obtained.

Although Fig. 5 explains the means for measuring the distance to the target object (6), the ultrasonic probe (2)
) can be similarly applied to the case of measuring the thickness of the target object (6) by arranging them so as to face both sides of the target object (6). Child Zs and super j′ for proofreading? Although the explanation has been made assuming that the wave transducer lK is connected to the transmitting/receiving circuit 1111 of the J (transmitting/receiving circuit), the two may be connected to separate transmitting/receiving circuits, and the operation is exactly the same in that case.

[Effect of the invention] In this invention, a measuring ultrasonic probe and 31 (19
) Since the influence of air temperature fluctuations between the objects to be measured can be kept to a minimum, the ultrasonic wave f? This has the effect of preventing a decrease in measurement accuracy due to changes in speed, etc.

[Brief explanation of drawings]

Fig. 1 is a diagram showing an embodiment according to the present invention, and Fig. 2 is a diagram showing an embodiment according to the invention.
A diagram for explaining the relationship between the ultrasonic echo and the ultrasonic propagation time in the embodiment shown in the figure, FIG. 3 shows another embodiment according to the present invention, and the fourth opening is the FIG. 5 is a diagram for explaining the relationship between the sound wave echo and the ultrasonic propagation time 11}j, and FIG. 5 shows still another embodiment according to the present invention. FIGS. 7 and 8 are diagrams for explaining the relationship between echoes and ultrasonic propagation times, and are diagrams for explaining the conventional technique 1. In the figure, (1) is one transmitter circuit, (2]") is super?
Wave transmitting probe, (2R) is ultrasonic receiving probe, (3)
is the receiving circuit (4) is the time detection circuit, (5) is the k'li separation calculation rMI path, (6) is the object to be measured, (7) is the ultrasonic reflector, and (8) is the temperature detector (20). ZK is an ultrasonic transducer for calibration, and ZS is an ultrasonic transducer for measurement. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (3)

[Claims] (1) One or more measurement ultrasonic probes for transmitting ultrasonic waves toward a target object and receiving ultrasonic waves reflected from the target object, and the measurement ultrasonic probe. an ultrasonic reflector provided to block a portion of the ultrasonic beam at a certain distance in front of the measuring ultrasonic probe; a transmitting circuit that supplies electric pulses for transmitting to the measuring ultrasonic probe; a receiving circuit that amplifies the electrical signal received from the probe; a first time detection circuit that extracts the ultrasonic propagation time from the signal obtained from the receiving circuit to the echo reflected from the target object; and the receiving circuit. a second time detection circuit that extracts the ultrasonic propagation time from the ultrasonic reflector to the echo reflected by the signal obtained from the ultrasonic reflector, and inputs the output signals of the first and second time detection circuits;
Using the distance and ultrasonic propagation time between the measurement ultrasonic probe and the ultrasonic reflector and the ultrasonic propagation time between the measurement ultrasonic probe and the target object, the measurement An ultrasonic measuring device comprising: a distance calculation circuit that calculates the distance from an ultrasonic probe to a target object. (2) one or more measurement ultrasonic probes for transmitting ultrasonic waves toward a measurement target object and receiving ultrasonic waves reflected from the measurement target object; a temperature detector disposed in the propagation path of the ultrasonic beam in the air or in the liquid between the probe and the object to be measured; a transmission circuit that supplies electric pulses for transmission to the measurement ultrasonic probe; a receiving circuit that amplifies the electric signal received from the ultrasonic probe for use in the ultrasonic probe; a time detecting circuit that extracts the ultrasonic propagation time from the signal obtained from the receiving circuit to the echo reflected from the object to be measured; By inputting the output signals of the detection circuit and the temperature detector, and using the temperature obtained by the temperature detector and the ultrasonic propagation time obtained by the time detection circuit, the measurement ultrasonic probe is An ultrasonic measurement device comprising: a distance calculation circuit that calculates a distance from a feeler to an object to be measured. (3) A measurement ultrasonic transducer for transmitting ultrasonic waves toward a target object and receiving ultrasonic waves reflected from the target object, and a measurement ultrasonic transducer adjacent to and in the same case as the measurement ultrasonic transducer. a calibration ultrasonic transducer housed in the calibration ultrasonic transducer; and an ultrasonic reflector provided at a certain distance in front of the calibration ultrasonic transducer to block the ultrasonic beam transmitted by the calibration ultrasonic transducer. a transmission circuit that supplies electrical pulses for transmission to the measurement ultrasonic transducer and the calibration ultrasonic transducer, and amplifies the electrical signals received from the measurement ultrasonic transducer and the calibration ultrasonic transducer. a receiving circuit, a first time detection circuit that extracts the ultrasonic propagation time from the target object to the echo reflected from the target object using the signal obtained from the receiving circuit; A second time detection circuit extracts the ultrasonic propagation time from the echo to the reflected echo, and the output signals of the first and second time detection circuits are inputted to the calibration ultrasonic transducer and the ultrasonic reflector. Distance calculation for calculating the distance from the measuring ultrasonic transducer to the target object using the distance and ultrasonic propagation time between the measuring ultrasonic transducer and the target object. An ultrasonic measuring device characterized by comprising a circuit.