JPS58216918A - Method and device for detecting liquid - Google Patents

Abstract

PURPOSE:To detect the presence or absence of liquid in a container, by inputting an ultrasonic wave to the wall of the container that contains liquid at a specified angle, and detecting the propagated wave or reflected wave of the inputted ultrasonic wave at the wall surface of the container. CONSTITUTION:A wedge 2, which has a slant surface of a specified angle, is intimately provided on the wall of a container that contains liqud, and an ultrasonic wave oscillator 3 is arranged. Another wedge 4, which has a slant surface of a spcified angle, is intimately provided, and an ultrasonic wave receiver 5 is arranged. Said wedges 2 and 4 are linked by a linking tool 6 to each other. An ultrasonic wave, which is generated by the ultrasonic oscillator 3, is inputted to a container wall through the wedge 2 at a specifid angle. A plate wave A shown by a wave line is generated and propagated. Said wave enters the ultrasonic wave receiver 5 through the wedge 4 and is detected here. The presence or absence of the liquid in the container can be found by the signal level detected by said receiver 5.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid detection method using ultrasonic waves and a detection device thereof.

When detecting the presence of liquid inside (or outside) a container, if the container is movable, it can be detected by means such as applying vibration to the container or measuring its weight.

Furthermore, if the container is fixed and can be processed, detection can be made by attaching a peephole or the like to the container. However, if the container is fixed and cannot be processed, it is difficult to detect the presence or absence of liquid inside (or outside) the container from the outside (or inside) of the container.

The present invention has been made in view of the above circumstances, and its purpose is to use ultrasonic waves to easily detect the presence or absence of liquid even in containers that are fixed and cannot be processed. The purpose of the present invention is to obtain a liquid detection method and a detection device therefor.

That is, the first invention involves injecting ultrasonic waves at a certain angle toward the wall of a container containing liquid, detecting propagation waves or reflected waves of the incident ultrasonic waves from the wall surface of the container, and detecting the detected ultrasonic waves. This liquid detection method is characterized by detecting the presence or absence of liquid in a container based on the intensity of sound waves.

The second invention also provides an ultrasonic oscillator disposed at a distance from the wall of a container containing a liquid, and an ultrasonic oscillator closely interposed between the oscillator and the wall and arranged at a certain angle. A wedge that propagates sound waves to the wall, a wedge that is in close contact with the wall of the container and that transmits the propagation wave or reflected wave of the incident ultrasonic wave, and an ultrasonic receiver that comes into contact with the wedge and receives the transmitted ultrasonic wave. This liquid detection device is characterized in that it is equipped with a wave receiver and detects the presence or absence of liquid in a container from the intensity of ultrasonic waves obtained by the wave receiver.

Furthermore, the third invention provides a plurality of ultrasonic excavators having different oscillation frequencies, which are disposed at intervals from the wall of a container containing liquid, and which are closely interposed between the oscillators and the wall. a plurality of wedges each having a second surface having a different angle from each other;
A plurality of wedges having slopes at different angles from each other that are in close contact with the walls of the container and transmit propagating waves or reflected waves of the incident ultrasonic waves, and a plurality of wedges that are in contact with the same wedges and receive the transmitted ultrasonic waves. This liquid detection device is characterized in that it is equipped with an ultrasonic wave receiver, and detects the presence or absence of liquid in a container from the intensity of the ultrasonic waves obtained by the wave receiver.

The present invention will be explained below with reference to the drawings.

The method of the present invention is a method in which ultrasonic waves are incident at a fixed angle toward the wall of a container such as a tank that stores liquid, and propagated waves or reflected waves of the incident ultrasonic waves are detected from the wall surface of the container.

In this method, when liquid is present, the ultrasonic waves are absorbed and attenuated, so the presence or absence of liquid can be detected by detecting the intensity.

Devices used in this method include liquid detection devices shown in FIGS. 1 to 9. The liquid detection device shown in FIGS. 1 and 2 has an ultrasonic oscillator 3 disposed with a wedge 2 having an inclined surface at a predetermined angle closely interposed between B and zl of a container containing a liquid.
The ultrasonic receiver 5 is disposed with another wedge 4 having a slope at a predetermined angle closely interposed therebetween, and the wedges 2 and 4 are connected to each other by a connector 6.

This liquid detection device causes ultrasonic waves generated from an ultrasonic excavator 3 to be incident on a container wall 1 at a constant angle using a wedge 2. When an ultrasonic wave is incident on the container wall 1, a plate wave A shown by a broken line in FIG. 2 is generated and propagated. This wave is a wedge 4
The waves enter the ultrasonic receiver 5 and are detected there. If the signal level detected by the wave receiver 5 is lower than a predetermined value, the plate wave A is absorbed and attenuated on the way, which indicates that liquid is present in the container. . Moreover, if it is higher than a predetermined value, it can be seen that there is no liquid in the container.

FIG. 3 shows an ultrasonic oscillator that also serves as a receiver. This device transmits the ultrasonic waves generated from the ultrasonic oscillator 3 to the wedge 2.
The reflected wave from the container wall 1 is detected by the oscillator 3 (which also serves as a wave receiver), and the presence or absence of liquid is detected from the intensity of the wave. The effect of this device is similar to that of FIG. 1.

FIG. 4 shows that in the liquid detection device of FIG. 1 or 3,
A circuit for reliably detecting the presence or absence of liquid is shown. This circuit includes a liquid detection device 7, a circuit 8 that drives it, a circuit 9 that amplifies the signal from the sensor, an f-) circuit 10 that extracts only the necessary signal from this signal, and a peak value detection circuit 10. Circuit 1 to hold and circuit 1 to generate reference signal
2, a comparison circuit 13 that compares the output of the detection hold circuit 1 with the reference signal of the reference signal generation circuit 12 and detects the magnitude, and an indicator I4 that displays the signal of the circuit 12. ing.

In this circuit, the drive circuit 8 operates the liquid detection device 7 to generate plate waves on the container wall 1, and the waves that propagate through the container wall 1 and are reflected are detected.

The detected signal is amplified by an amplifier circuit 9 and then sent to a gate circuit 10.
The timing from the drive circuit 8 is determined, the gate is opened for the necessary time, and the signal is taken out.

This peak value is detected and held by the detection and hold circuit 1. Then, the signal level from the reference signal generation circuit 12 is compared with the comparison circuit 13, and when it is lower than the reference value, an ON signal is output, and when it is higher, an OFF signal is output, and the display 14
outputs whether liquid is present. Therefore, by using this circuit, it is possible to clearly output the presence or absence of liquid.

5 and 6 show a further different liquid detection device of the present invention, which is applied when an object 15 is present close to the outside of the container wall 1, as shown in FIG. In this case, the ultrasonic wave passes through the container wall 1 as a plate wave A, reaches the object 15 from the outer wall surface of the container through the liquid 16, and returns as a reflected wave B. For this reason, the detection signal level may change and become higher than when there is no object 15, and as a result, there is no difference from when there is no liquid, and there is a possibility that a determination of the presence or absence of liquid may be required. This device is designed to prevent errors in judgment by combining ultrasonic oscillators with different frequencies.

That is, this liquid detection device has a plurality of ultrasonic oscillators 3a to 3c arranged with a plurality of wedges 2a to 2c closely interposed in a wall 1 of a container containing liquid, and a plurality of wedges 4a to 4c. A plurality of ultrasonic receivers 5a are closely interposed.
5c respectively, and wedges 2a to 2c and 411L to
4c are connected by a connector 6.

The ultrasonic oscillators 3a to 3c oscillate different frequencies, and correspond to the ultrasonic receivers 5a to 5c, respectively. The wedges 2a to 2c have different angles from each other,
The slopes are set to provide the optimum angle of incidence for generating plate waves. Similarly, the wedges 5a to 5c have different angles from each other.

In this liquid detection device, when an ultrasonic oscillator 3a emits a predetermined frequency, the ultrasonic wave propagates to the container wall 1 via the wedge 2a. This wave, if the liquid 16 is not present,
It propagates through the container Dne 1 and is detected by the receiver 5a. On the other hand, when there is a liquid 16 and an object 15 nearby, the ultrasonic waves pass through the liquid 16 and are reflected back to the object 15, as shown in FIG. If the phase of the vibration of this reflected wave matches the phase of the wave propagating inside the container wall 1, they will strengthen each other and the signal level will become high. On the other hand, if they deviate by 1800, they cancel each other out and decrease. This also occurs in the case of the oscillators 3 b r 3 c, but since the frequencies are different, the wavelength in the liquid changes, the phase of the reflected wave changes, and as a result, the way of cancellation or emphasis differs, and the received signal Levels change. On the other hand, when no liquid is present, such signal level changes are unlikely to occur. For this reason, there may be a difference in the received signal level of any of the receivers 5b to 5c between when the liquid 16 is present and when it is not, and the presence or absence of the liquid 16 is detected based on the difference. be able to.

According to this liquid detection device, since the detection is performed using ultrasonic waves having different frequencies, it is possible to easily determine the presence or absence of liquid even when an object is approaching.

FIGS. 8 and 9 show a device in which the ultrasonic oscillator also serves as a receiver in the device shown in FIG. This device transmits ultrasonic waves generated from an ultrasonic oscillator 3 to a container wall 1 using a wedge 4.
The reflected wave from the container wall 1 is detected by the oscillator 3 (which also serves as a wave receiver), and the presence or absence of liquid is detected from its intensity.

This device also produces the same effects as the one shown in FIG.

As described above, according to the present invention, since the presence or absence of liquid is detected using the attenuation of ultrasonic waves, it is extremely effective in detecting the presence or absence of liquid inside or outside a container that is fixed and cannot be processed. be. Further, according to the second invention, it is only necessary to attach it to the inner wall or outer wall of the container, and the operation becomes easy. Furthermore, according to the third invention, since ultrasonic waves of a plurality of different frequencies are used, remarkable effects such as being able to reliably detect the presence or absence of liquid even if an object is present near the container are achieved.

[Brief explanation of drawings]

FIG. 1 is a front view of a liquid detection device showing one embodiment of the present invention, FIG. 2 is an explanatory view of the same operation, FIG. 3 is a front view of a liquid detection device showing another embodiment of the invention, The figure is a block diagram showing the detection circuit of the liquid detection device, FIG. 5 is a plan view of the liquid detection device showing another embodiment of the present invention, FIG. 6 is a front view of the same, and FIG. FIG. 8 is a plan view of a liquid detection device showing still another embodiment of the present invention, and FIG. 9 is a front view thereof. 1...Wall, 2.2a-2c...Wedge, 3,3th
~3c...Ultrasonic oscillator, 4.4a~4c...Wedge, 5,5a~5c...Ultrasonic receiver, 6...Connector, 7...Liquid detection device, 8. ...Drive circuit, 9...
・Amplification circuit, 1o...r-) circuit, 1no... detection bold circuit, 12... reference signal generation circuit, 13...
Comparison circuit, 14... Display device, 15... Object, 16.
··liquid. Applicant's sub-agent Patent attorney Takehiko Suzue Figure 1 Figure 38 Figure 41Q Figure 5 Figure 6 Figure 7E Figure 8 Figure 9h

Claims (3)

[Claims] (1) Ultrasonic waves are incident at a certain angle toward the wall of a container containing a liquid, the propagation waves or reflected waves of the incident ultrasonic waves are detected from the container wall, and the intensity of the detected ultrasonic waves is determined from the intensity of the detected ultrasonic waves. A liquid detection method characterized by detecting the presence or absence of liquid in a container. (2) An ultrasonic oscillator placed at a distance from the wall of a container containing liquid, and an ultrasonic oscillator closely interposed between the oscillator and the wall to propagate ultrasonic waves to the wall at a certain angle. a wedge that is in close contact with the wall of the container and that transmits the propagation wave or reflected wave of the incident ultrasonic wave, and an ultrasonic receiver that is in contact with the wedge and receives the transmitted ultrasonic wave. death,
A liquid detection device that detects the presence or absence of liquid in a container based on the intensity of ultrasonic waves obtained by the receiver. (3) A plurality of ultrasonic oscillators with different oscillation frequencies are arranged at a distance from the wall of a container containing a liquid, and ultrasonic oscillators with different oscillation frequencies are arranged closely between the oscillators and the wall. a plurality of wedges having different slopes; a plurality of wedges each having slopes at different angles that are in close contact with the wall of the container and transmitting propagating waves or reflected waves of the incident ultrasonic waves; A liquid detection device comprising a plurality of ultrasonic receivers that receive transmitted ultrasonic waves, and detects the presence or absence of liquid in a container from the intensity of the ultrasonic waves obtained by the receivers. .