JPH06174530A - Ultrasonic distance measuring apparatus - Google Patents

Abstract

PURPOSE:To make it possible to measure the level of sediment having heavy specific gravity and the level of floating sludge having light specific gravity at the same time. CONSTITUTION:The apparatus for measuring the levels of sediment and floating sludge has the parts performing the functions as follows. An ultrasonic sensor 4 transmits the ultrasonic wave of the frequency of 200KHz toward the lower side from the upper side in the liquid in a sediment tank 3. An ultrasonic sensor 5 transmits the ultrasonic wave of the frequency of 400KHz toward the lower part from the upper side in the liquid in the sediment tank 3. A time measuring part 17 measures the times until the ultrasonic waves transmitted to the surface of the sediment 1 and the surface of the floating sludge 2 are reflected and returned based on the detected signals from the ultrasonic sensors 4 and 5. An operating part 18 measures the distances to the sediment 1 and the floating sludge 2 based on the measured times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic distance measuring device, and more particularly to measuring sediment level in a sedimentation tank, sludge level in a storage tank for various liquid raw materials and fuels, and granular material cleaning tank. The present invention relates to an ultrasonic distance measuring device suitable for measuring internal levels.

[0002]

2. Description of the Related Art Conventionally, in a settling tank such as a tank or a sewage treatment facility where solids or suspended solids are settled, when measuring the settling level of the solids, one settling tank is usually used. It is common to deploy one sensor to measure sediment levels. On the other hand, in a large settling tank,
In order to be able to measure the sediment level in each part in the sedimentation tank, there is a case where a plurality of sensors of the same standard are arranged in one sedimentation tank to measure the sediment level.

FIG. 3 shows an ultrasonic sensor 50 and a level meter 5.
FIG. 2 is a principle diagram in the case of measuring the level of the sediment 53 in the sedimentation tank 52 using No. 1 and emitting an ultrasonic pulse toward the sediment 53 from the ultrasonic sensor 50 arranged in the water of the sedimentation tank 52. Based on the time T until the ultrasonic pulse is reflected back from the surface of the sediment 53 and returned by the level meter 51 and the speed of sound V in water, the distance L from the ultrasonic sensor 50 to the surface of the sediment 53 is L = 1. / 2 (V x T) is measured. In this case, assuming that the sound velocity V in water is 1500 m / sec, the wavelength of the ultrasonic wave of 200 KHz is 7.5 mm,
The wavelength of the ultrasonic wave of 400 KHz is 3.75 mm, 1 MHz
The ultrasonic wave has a wavelength of 1.5 mm.

[0004] Usually, the sediment in the sedimentation tank is generally formed by forming layers from the bottom of the sedimentation tank in descending order of specific gravity. For example, as shown in FIG. In the large settling tank 60 installed in the above (for example, a diameter of 8 m and a height of 4 m in the illustrated example), a large stirrer (reiki stirrer (Reiki) is connected to the output shaft of the stirring motor 61 via a rod-shaped member 62, support members 63, 64 and the like. ) 65 is attached to the stirring motor 61
The stirrer 65 is driven by to stir the precipitate 66 so that the precipitate 66 does not completely solidify at the bottom of the settling tank 60, so that the above phenomenon occurs remarkably. In this case, on the surface layer of the sediment 66, a sediment having a light specific gravity that does not fully sediment forms a suspended sludge layer 67.

[0005]

However, in the case of measuring the level of the precipitates forming the layers in the descending order of specific gravity in the precipitation layer by the above-mentioned conventional ultrasonic measurement method,
Since the level of the strongest reflection of the ultrasonic pulse emitted from the ultrasonic sensor toward the sediment in the sedimentation tank will be measured, the state (sediment or suspended sludge) in the sedimentation tank will be measured closely. However, there is a problem in that the conventional technique cannot sufficiently cope with the situation when measuring the level of floating sludge that easily overflows.

[0006]

An object of the present invention is to improve the disadvantages of the above conventional example, and in particular, by disposing two kinds of ultrasonic sensors having different frequencies with respect to one level meter, precipitation having a large specific gravity is achieved. An object of the present invention is to provide an ultrasonic distance measuring device capable of simultaneously measuring the level of a substance and the level of floating sludge having a low specific gravity.

[0007]

Means for Solving the Problems The present invention is to emit ultrasonic waves to a sediment that has settled at the bottom of a liquid in a settling tank or floating sludge suspended in the liquid, and the ultrasonic waves reflected from the sediment and the floating sludge. In an ultrasonic distance measuring device for measuring the distance to the sediment or the floating sludge based on the detection of sound waves, the ultrasonic wave of a relatively low frequency is emitted downward from above in the liquid of the settling tank. No. 1 ultrasonic sensor, a second ultrasonic sensor that emits ultrasonic waves of a relatively high frequency downward from above in the liquid of the precipitation tank, the first ultrasonic sensor and the second ultrasonic sensor. Based on each detection signal of the sound wave sensor, a time measuring means for measuring the time until the ultrasonic waves radiated to the surface of the sediment and the surface of the floating sludge are reflected and returned, and are measured by the time measuring means Based on the measured time It has a configuration comprising an arithmetic means for measuring the respective distances of the fine until said floating sludge. This achieves the above object.

[0008]

According to the present invention, since the ultrasonic waves of low frequency emitted downward from the liquid in the settling tank from the first ultrasonic sensor have a long wavelength, they pass through the suspended sludge with small particles, The high-frequency ultrasonic waves reflected downward by the precipitate below and returning to the first ultrasonic sensor while being emitted downward from the second ultrasonic sensor into the liquid in the sedimentation tank have a short wavelength, so that the particles are Is reflected by the small suspended sludge and returns to the second ultrasonic sensor. The time measuring means measures, based on the detection signal of the first ultrasonic sensor, the time until the ultrasonic waves radiated to the surface of the sediment are reflected and returned, and use the detection signal of the second ultrasonic sensor as the detection signal. Based on this, the time until the ultrasonic waves emitted to the surface of the floating sludge are reflected and returned is measured. The calculating means measures the distance to the sediment and the distance to the floating sludge based on each measurement time by the time measuring means. From the above, it is possible to simultaneously measure the distance to the sediment deposited at the bottom of the sedimentation tank and the distance to the floating sludge suspended in the liquid of the sedimentation tank. Even in a sedimentation tank of a wastewater treatment facility or the like that forms and precipitates, it is possible to accurately measure the state of sediment, floating sludge and the like in the sedimentation tank and the distance to the floating sludge that easily overflows.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the ultrasonic distance measuring device of the present invention is applied to a sediment and floating sludge level measuring device will be described below with reference to the drawings.

First, the structure of a sediment and floating sludge level measuring apparatus using the ultrasonic sensor of this embodiment will be described with reference to FIG. 2. The sediment 1 having a large specific gravity and large particles 1
In the water of the settling tank 3 in which the floating sludge 2 having a small specific gravity and small particles is settled, for example, an ultrasonic frequency of 200 KH
z ultrasonic sensor 4 and, for example, an ultrasonic frequency of 400K
The ultrasonic sensor 5 of Hz is arranged, and the ultrasonic sensor 4 and the ultrasonic sensor 5 are connected to a level meter 8 having various parts described later via lead wires 6 and 7. The ultrasonic sensor 4 having an ultrasonic frequency of 200 KHz is used for the sediment 1
The ultrasonic sensor 5 having an ultrasonic frequency of 400 KHz is used to measure the level of the suspended sludge 2.

Next, the sediment and floating sludge level measuring system of the present embodiment will be described with reference to FIG. 1. The sediment and floating sludge level measuring system is composed of an ultrasonic sensor 4 having an ultrasonic frequency of 200 KHz and the ultrasonic sensor. A transmission pulse generating unit 9, an amplifying unit 10, and a waveform shaping unit 1 forming a signal input / output system of the sound wave sensor 4.
1, a detection unit 12, an ultrasonic sensor 5 having an ultrasonic frequency of 400 KHz, a transmission pulse generation unit 13, an amplification unit 14, and a waveform shaping unit 1 which constitute a signal input / output system of the ultrasonic sensor 5.
5, the detection unit 16 and the time measurement unit 17 that constitutes the control system,
Operation unit 1 and operation unit 1 constituting input / output and display system
9, a display unit 20, and an output unit 21 are provided.

The transmission pulse generator 9 outputs a drive signal to the ultrasonic sensor 4 based on the control signal from the time measuring unit 17, and the ultrasonic sensor 4 receives the drive signal from the transmission pulse generator 9 to settling tank. Ultrasonic waves are emitted into the inside of the precipitate 3, and the ultrasonic waves reflected from the surface of the precipitate 1 are output to the amplification section 10. The amplification unit 10 outputs an amplified signal obtained by amplifying the output signal of the ultrasonic sensor 4 to the waveform shaping unit 11, and the waveform shaping unit 11 outputs the waveform shaped signal obtained by shaping the output signal of the amplification unit 10 to the detection unit 12. The detection section 12 outputs the detection signal obtained by detecting the output signal of the waveform shaping section 11 to the time measuring section 17.

Similarly, the transmission pulse generator 13 outputs a drive signal to the ultrasonic sensor 5 based on the control signal of the time measuring unit 17, and the ultrasonic sensor 5 transmits the drive pulse.
The ultrasonic wave is emitted into the settling tank 3 based on the drive signal of the above, and the ultrasonic wave reflected from the surface of the floating sludge 2 is output to the amplification section 14. The amplification unit 14 outputs the amplified signal obtained by amplifying the output signal of the ultrasonic sensor 5 to the waveform shaping unit 15, and the waveform shaping unit 15 outputs the waveform shaped signal obtained by shaping the output signal of the amplification unit 14 to the detection unit 16. Output and detect section 16
Outputs a detection signal obtained by detecting the output signal of the waveform shaping section 15 to the time measuring section 17.

The time measuring unit 17 measures the time T1 until the ultrasonic wave emitted from the ultrasonic sensor 4 having an ultrasonic frequency of 200 KHz is reflected from the surface of the sediment 1 and returns based on the output of the detection unit 12. At the same time, based on the output of the detection unit 16, the time T2 until the ultrasonic waves emitted from the ultrasonic sensor 5 having an ultrasonic frequency of 400 KHz are reflected from the surface of the floating sludge 2 and returned is measured. The calculating unit 18 calculates the time T1 output from the time measuring unit 17,
A distance L1 = 1/2 (V × T1) from the ultrasonic sensor 4 to the surface of the sediment 1 is measured based on the sound velocity V in water, and a time T2 output from the time measuring unit 17 is measured.
And the speed of sound V in water, the distance L2 = 1/2 (V × T2) from the ultrasonic sensor 5 to the surface of the floating sludge 2
Is designed to measure.

The operation unit 19 is used by the measurement operator to set the level meter 8, and outputs a signal based on a predetermined setting to the calculation unit 18. Display unit 20
Is the sediment 1 from the ultrasonic sensor 4 measured by the calculation unit 18.
The distance L1 to the surface, the distance L2 from the ultrasonic sensor 5 to the surface of the floating sludge 2 and the like are displayed. The output unit 21 outputs the measured distance, various data, and the like by printing or the like.

Next, the operation of this embodiment configured as described above will be described.

When the measuring operator sets the level meter 8 to the ultrasonic reflection characteristics of the sediment to be measured from the operating section 19, a setting signal from the operating section 19 is transmitted from the operating section 19 to the time measuring section 17 As a result of being supplied to
A drive signal is supplied to the ultrasonic sensor 4 via the transmission pulse generator 9 and a drive signal is supplied to the ultrasonic sensor 5 via the transmission pulse generator 13. Thereby, the ultrasonic sensor 4
An ultrasonic wave having a frequency of 200 KHz is emitted into the sedimentation tank 3, and the ultrasonic sensor 5 emits an ultrasonic wave having a frequency of 400 KHz into the sedimentation tank 3.

The ultrasonic wave emitted from the ultrasonic sensor 4 and reflected from the surface of the precipitate 1 is amplified by the amplifying section 10, shaped by the waveform shaping section 11 and detected by the detecting section 12, and then the time measuring section. 17 is supplied. Similarly, the ultrasonic waves emitted from the ultrasonic sensor 5 and reflected from the surface of the floating sludge 2 are amplified by the amplification unit 14, and the waveform shaping unit 15 is provided.
After the waveform is shaped by and detected by the detection unit 16,
It is supplied to the time measuring unit 17.

In this case, the reflection amount of the ultrasonic waves emitted to the sediment 1 (floating sludge 2) from the sediment 1 (floating sludge 2) depends on the wavelength of the ultrasonic waves used and the sediment 1 (floating sludge 2). Differences occur depending on the size of the particles. That is, since the ultrasonic wave having a low frequency has a long wavelength, it passes through the suspended sludge 2 having small particles and is reflected by the sediment 1 having large particles below the suspended sludge 2. On the other hand, since the ultrasonic wave having a high frequency has a short wavelength, a sufficiently detectable amount is reflected even from the suspended sludge 2 having small particles.

The time measuring unit 17 measures the time T1 until the ultrasonic wave emitted from the ultrasonic sensor 4 is reflected from the surface of the sediment 1 and returns based on the output of the detection unit 12, and Based on the output, the time T2 until the ultrasonic waves emitted from the ultrasonic sensor 5 are reflected from the surface of the floating sludge 2 and returned is measured. Thereby, the calculation unit 18 calculates the distance L1 = 1/2 (V × T1) from the ultrasonic sensor 4 to the surface of the sediment 1 based on the time T1 output from the time measurement unit 17 and the sound velocity V in water. And the distance L2 = 1/2 (V × T2) from the ultrasonic sensor 5 to the surface of the floating sludge 2 based on the time T2 output from the time measuring unit 17 and the sound velocity V in water. The measurement result is displayed on the display unit 20 and output from the output unit 21.

As described above, according to this embodiment, the ultrasonic sensor 4 having a low frequency (for example, 200 KHz) is used for measuring the level of the precipitate 1 having large particles and heavy specific gravity. Since a high frequency (for example, 400 KHz) is used for measuring the level of the suspended sludge 2 that is light, one set of the level meter 8 can be used to set the sedimentation tank 3
It is possible to simultaneously measure the level of the sediment 1 that has settled at the bottom of the tank and the level of the floating sludge 2 that has floated in the water in the settling tank 3. As a result, for example, even in a sedimentation tank of a wastewater treatment facility or the like in which the sediments form a layer in the order of descending specific gravity, the state of the sediments and suspended sludge in the sedimentation tank can be precisely measured. In addition, the level of floating sludge that easily overflows can be accurately measured.

In this embodiment, the sediment and floating sludge level measuring device is applied to measure the level of sediment and floating sludge in the settling tank. However, for example, various liquid raw materials and fuels are stockpiled. It can be applied to the case of measuring the sludge level in the tank, the case of measuring the level of the granular material in the cleaning tank, and the like.

[0023]

As described above, according to the ultrasonic distance measuring apparatus of the present invention, the ultrasonic waves emitted from the two kinds of ultrasonic sensors having different ultrasonic frequencies to the surface of the sediment and the surface of the suspended sludge are reflected. The distance to the sediment and floating sludge is measured based on the time it takes to return. Therefore, the distance to the sediment that has settled to the bottom of the sedimentation tank and the floating in the liquid in the sedimentation tank It is possible to measure the distance to the floating sludge at the same time, and as a result, for example, even in a sedimentation tank of a wastewater treatment facility or the like in which sediments form a layer in order of descending specific gravity It is possible to obtain remarkable effects such as the state of sediments and floating sludge, etc., and the distance to the floating sludge that easily overflows.

[Brief description of drawings]

FIG. 1 is a block diagram of a sediment and floating sludge level measuring system of an example to which the present invention is applied.

FIG. 2 is a schematic diagram showing a measurement state of the ultrasonic sensor in the settling tank of the present embodiment.

FIG. 3 is a schematic diagram showing a measurement state of an ultrasonic sensor in a settling tank of a conventional example.

FIG. 4 is a schematic view showing a stirring state in a settling tank of a conventional example.

[Explanation of symbols]

 1 Sediment 2 Floating Sludge 3 Settling Tank 4 Ultrasonic Sensor as First Ultrasonic Sensor 5 Ultrasonic Sensor as Second Ultrasonic Sensor 6 Level Meter 9,13 Transmission Pulse Generator 10,14 Amplifier 11, 15 waveform shaping section 12, 16 detection section 17 time measuring section as time measuring means 18 arithmetic section as arithmetic means 19 operation section 20 display section 21 output section

Claims (1)

[Claims] 1. An ultrasonic wave is emitted to a sediment settled in the bottom of the settling tank or floating sludge suspended in the solution, and the settling is performed based on detection of the ultrasonic wave reflected from the precipitate or the suspended sludge. In an ultrasonic distance measuring device for measuring the distance to an object or the floating sludge, a first ultrasonic sensor for emitting an ultrasonic wave of a relatively low frequency from above in the liquid of the settling tank to above, and Based on a second ultrasonic sensor that emits ultrasonic waves of a relatively high frequency downward from above in the liquid of the settling tank, and detection signals of the first ultrasonic sensor and the second ultrasonic sensor And a time measuring means for measuring a time until ultrasonic waves radiated to the surface of the sediment and the surface of the floating sludge are reflected and returned, and the sediment based on the measurement time measured by the time measuring means. And each up to the floating sludge Release ultrasonic distance measuring apparatus characterized by comprising a calculating means for measuring.