JPH10197319A - Ultrasonic level measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the level of a liquid and the displacement of the level with high accuracy and in a wide range by a method wherein an ultrasonic transmitter- receiver for measurement is moved in the up-and-down direction by a movement means (a lifter device) so as to be situated in a position which is suitable for the measurement of the level. SOLUTION: On the basis of a detection signal from an ultrasonic transmitter- receiver 4 for measurement, a signal which is proportional to the distance between the ultrasonic transmitter-receiver 4 for measurement and a level 21 is sent to a processing unit 9 from an ultrasonic measuring device 8 for measurement. In addition, on the basis of a detection signal from an ultrasonic transmitter-receiver 3 for correction, a signal which corrects a sound velocity is sent to the processing unit 9 from an ultrasonic measuring device 7 for correction. On the basis of the signal obtained from the ultrasonic measuring device 7 for correction and on the basis of the signal obtained from the ultrasonic measuring device 8 for measurement, the processing unit 9 computes the distance between the ultrasonic transmitter-receiver 4 for measurement and the level 21. Then, a lifter device 12 is controlled by a lifter control device 13, the ultrasonic transmitter-receiver 4 for measurement is moved to a position which is suitable for the measurement of the level, and the level of a liquid 2 and the displacement of the level can be measured with high accuracy.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic liquid level measuring apparatus for measuring a liquid level in a liquid container such as a pit or a tank with high accuracy using an ultrasonic wave over a wide range.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view showing the structure of a conventional ultrasonic liquid level measuring apparatus of this kind. In this device, the measuring ultrasonic transmitter / receiver 4 transmits the ultrasonic wave 6 and reflects the echo wave of the ultrasonic wave 6 reflected from the liquid surface 21 of the liquid 2 contained in the pit 1 into the measuring ultrasonic transmitter / receiver. 4 receives. Then, the measuring ultrasonic measuring device 8 is connected to the measuring ultrasonic transmitting / receiving device 4.
A signal proportional to the time from the transmission of the ultrasonic wave to the reception thereof is sent to the arithmetic processing unit 9.

At this time, in order to correct the sound speed of the ultrasonic waves in the air, the ultrasonic transmitter / receiver for correction 3 transmits the ultrasonic waves 5 to the ultrasonic reflecting plate 11 installed at a fixed distance, and the echo waves thereof To receive. Then, the correcting ultrasonic measuring device 7 sends a signal proportional to the time from the transmission of the ultrasonic wave to the reception of the echo wave in the correcting ultrasonic transmitter / receiver 3 to the arithmetic processing device 9.

The arithmetic processing unit 9 calculates a corrected sound speed from the signal sent from the correcting ultrasonic measuring device 7, and multiplies the signal indicating the sound speed by the signal transmitted from the measuring ultrasonic measuring device 8. Then, by calculating the distance between the measuring ultrasonic transceiver 4 and the liquid surface 21, the liquid level of the liquid 2 in the pit 1 and the displacement of the liquid level are calculated. The display device 10 displays the liquid level and the displacement of the liquid level calculated by the arithmetic processing device 9.

[0005]

In the above-mentioned conventional ultrasonic liquid level measuring apparatus, when the liquid level is to be measured with high accuracy, the distance between the ultrasonic transceiver 4 and the liquid surface 21 is reduced. There is a need. For this reason, when performing a wide range of liquid level measurement such as measuring all the liquid levels from the vicinity of the bottom surface to the upper portion of the pit 1, there is a problem that an error becomes large and the pit 1 cannot be used as a measuring device. An object of the present invention is to provide an ultrasonic liquid level measuring device capable of measuring the liquid level and the displacement of the liquid level in a liquid storage section with high accuracy and in a wide range.

[0006]

In order to solve the above-mentioned problems and achieve the object, an ultrasonic liquid level measuring apparatus according to the present invention is configured as follows. (1) The ultrasonic liquid level measuring device of the present invention is installed above the liquid container to measure the liquid level of the liquid in the liquid container, and transmits ultrasonic waves to the liquid surface of the liquid to transmit the liquid surface. A measuring ultrasonic transmitting / receiving means for receiving an echo wave from the apparatus, and transmitting a signal relating to a distance between the measuring ultrasonic transmitting / receiving means and the liquid surface based on a detection signal of the measuring ultrasonic transmitting / receiving means. Ultrasonic measuring means for measurement, and a correcting ultrasonic transmitting and receiving means for transmitting an ultrasonic wave to a predetermined member and receiving an echo wave from the predetermined member, in order to correct a signal related to the velocity of the ultrasonic wave in the air, A correcting ultrasonic measuring means for transmitting a signal relating to the speed correction based on a detection signal of the correcting ultrasonic transmitting / receiving means, and moving the measuring ultrasonic transmitting / receiving means in the vertical direction, Moving means for positioning the Based on the signals emitted from the measurement ultrasonic measuring means and the correction ultrasonic measurement means with the movement by means, and a, a calculating means for calculating the liquid level. (2) The ultrasonic liquid level measuring apparatus according to the present invention is the apparatus according to the above (1), wherein the predetermined member and the correcting ultrasonic transmitting / receiving means are at a fixed distance.

[0007] As a result of taking the above measures, the following operations occur. (1) According to the ultrasonic liquid level measuring apparatus of the present invention, the measuring ultrasonic transmitting / receiving means is moved up and down to be positioned at a position suitable for measuring the liquid level, and the ultrasonic measuring means for measuring and Since the liquid level is calculated based on each signal transmitted from the correction ultrasonic measurement unit, the measurement ultrasonic transmission / reception unit is appropriately moved even when the measurement range of the measurement ultrasonic measurement unit is small. By doing so, the liquid level of the liquid and the displacement of the liquid level can be measured with high accuracy over a wide range from the bottom surface to the upper portion of the liquid storage portion. That is, since the moving range of the measuring ultrasonic transmission / reception means can be set arbitrarily, the liquid level of the liquid and the displacement of the liquid level can be measured with high accuracy without being restricted by the measuring range. (2) According to the ultrasonic liquid level measuring apparatus of the present invention, since the predetermined member and the correcting ultrasonic transmitting / receiving means are at a fixed distance, the signal relating to the velocity of the ultrasonic wave can be accurately corrected. You.

[0008]

FIG. 1 is a sectional view showing a configuration of an ultrasonic liquid level measuring apparatus according to an embodiment of the present invention. FIG.
In FIG. 7, the same parts as those in FIG. 2 are denoted by the same reference numerals.
As shown in FIG. 1, a lifter device 12 is fixed inside a side wall of a concrete pit 1 which is a liquid container. The measuring ultrasonic transmitter / receiver 4 is attached to the movable section 121 of the lifter device 12, and the measuring ultrasonic transmitter / receiver 4 can be moved up and down by the movable section 121. The measuring ultrasonic transceiver 4 transmits the ultrasonic waves 6 and receives the echo waves from the liquid surface 21.

A correcting ultrasonic transmitter / receiver 3 is fixed inside the side wall of the pit 1 opposite to the side wall. Further, on the inner side of the side wall below the correcting ultrasonic transmitter / receiver 3, a stainless steel ultrasonic reflecting plate 11 is fixed at a predetermined distance from the correcting ultrasonic transmitter / receiver 3 and parallel to the liquid surface 21. Have been.

[0010] The correcting ultrasonic transceiver 3 transmits the ultrasonic waves 5 to the ultrasonic reflecting plate 11 and receives the echo waves. As described above, the signal proportional to the time from the transmission of the ultrasonic wave to the reception of the echo wave in the correction ultrasonic transceiver 3 is transmitted from the correction ultrasonic measurement device 7 to the arithmetic processing device 9.
Sent to

In the arithmetic processing unit 9, the distance between the correcting ultrasonic transceiver 3 and the ultrasonic reflecting plate 11 is input in advance, and the correcting ultrasonic measuring device 3
From the signal obtained through the above, the sound speed of the ultrasonic wave at that time in the air (the speed of the ultrasonic wave), that is, the corrected sound speed is calculated. The arithmetic processing unit 9 multiplies the signal indicating the corrected sound velocity by a signal obtained from the measuring ultrasonic measuring instrument 8,
The distance between the measuring ultrasonic transceiver 4 and the liquid surface 21 is calculated. The arithmetic processing unit 9 measures the liquid level of the liquid 2 and the displacement of the liquid level based on the distance and the position signal from the bottom of the pit of the measuring ultrasonic transceiver 4 obtained from the lifter control device 13. . The liquid level of the liquid 2 and the displacement of the liquid level calculated by the arithmetic processing device 9 are displayed on the display device 10.

When the liquid level 21 of the liquid 2 fluctuates and exceeds the measurement range of the ultrasonic measuring device 8 for measurement, the lifter control device 13
, The lifter device 12 is controlled, and the ultrasonic transmitter / receiver 4 for measurement is arbitrarily moved up and down to an appropriate position by the movable portion 121. Thus, the liquid level of the liquid 2 and the displacement of the liquid level can be accurately measured.

(Summary of Embodiment) The configuration, operation and effect shown in the embodiment are summarized as follows. In the ultrasonic liquid level measuring device shown in the embodiment, a signal proportional to the distance between the ultrasonic measuring device 4 and the liquid surface 21 is generated based on the detection signal from the ultrasonic measuring device 4. It is sent from the measuring ultrasonic measuring device 8 to the arithmetic processing device 9. Also, based on the detection signal from the correcting ultrasonic transceiver 3,
A signal for correcting the sound speed in the air is sent from the correcting ultrasonic measurement device 7 to the arithmetic processing device 9. In the arithmetic processing unit 9, based on the signal obtained from the correcting ultrasonic measuring instrument 7 and the signal obtained from the measuring ultrasonic measuring instrument 8, the operation between the ultrasonic measuring transmitter / receiver 4 and the liquid surface 21 is performed. Is calculated.

When the distance between the measuring ultrasonic transmitter / receiver 4 and the liquid surface 21 increases and exceeds the measurement range of the measuring ultrasonic measuring device 8, the lifter device 12 is switched to the lifter control device 13
By moving the ultrasonic transmitter / receiver for measurement 4 to an appropriate position, the liquid level of the liquid 2 and the displacement of the liquid level can be measured with high accuracy.

As a result, the measurement range of the measuring ultrasonic measuring device 8 can be reduced, so that the errors of the signals transmitted from the measuring ultrasonic transmitting and receiving device 4 and the measuring ultrasonic measuring device 8 are also reduced, and the arithmetic processing is performed. The accuracy of the liquid level of the liquid 2 output from the device 9 and the displacement of the liquid level is improved. Furthermore, since the movement range of the lifter device 12 can be set arbitrarily, even when the measurement range of the measuring ultrasonic measurement device 8 is small, the lifter device 1
By moving 2, a wide range of measurement can be performed. In addition,
The present invention is not limited to only the above-described embodiment, and can be implemented with appropriate modification without departing from the scope of the invention.

[0016]

According to the present invention, it is possible to provide an ultrasonic liquid level measuring apparatus capable of measuring the liquid level and the displacement of the liquid in the liquid container with high accuracy and in a wide range.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an ultrasonic liquid level measuring device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a configuration of an ultrasonic liquid level measuring device according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pit (liquid accommodating part) 2 ... Liquid 21 ... Liquid level 3 ... Correction ultrasonic transmitter / receiver 4 ... Measurement ultrasonic transmitter / receiver 5 ... Ultrasonic wave (and echo wave) 6 ... Ultrasonic wave (and echo wave) 7 ... Ultrasonic measuring device for correction 8 ... Ultrasonic measuring device for measurement 9 ... Processing device 10 ... Display device 11 ... Ultrasonic reflecting plate 12 ... Lifter device 121 ... Movable part 13 ... Lifter control device

Claims (2)

[Claims] 1. A measuring device which is installed above the liquid container to measure the liquid level of the liquid in the liquid container, transmits ultrasonic waves to the liquid surface of the liquid, and receives echo waves from the liquid surface. Ultrasonic transmission / reception means, Based on the detection signal of the measurement ultrasonic transmission / reception means, a measurement ultrasonic measurement means for transmitting a signal related to a distance between the measurement ultrasonic transmission / reception means and the liquid surface, In order to correct a signal related to the speed of the ultrasonic wave in the air, a correcting ultrasonic transmitting and receiving unit that transmits an ultrasonic wave to a predetermined member and receives an echo wave from the predetermined member, Based on the detection signal, a correction ultrasonic measurement unit that transmits a signal related to the speed correction, and the measurement ultrasonic transmission / reception unit are moved up and down to be positioned at a position appropriate for the liquid level measurement. Moving means, and moving with the moving means. Wherein based on the signals emitted from the measurement ultrasonic measuring means and the correction ultrasonic measurement device, the liquid level ultrasonic liquid level measuring device comprising calculating means for calculating, by comprising a a. 2. The ultrasonic liquid level measuring apparatus according to claim 1, wherein said predetermined member and said correction ultrasonic transmission / reception means are at a fixed distance.