JP2578628Y2 - Interface device for suspended foreign matter - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a method for measuring the position of an interface by emitting ultrasonic waves toward an interface of a sedimentation tank for wastewater treatment, sewage treatment or the like and other foreign substances forming an interface in a liquid. The present invention relates to a transducer for performing the measurement and an interface measuring device provided with the transducer.

[0002]

2. Description of the Related Art Conventionally, as this type of transducer and interface measuring device, one disclosed in Japanese Patent Application Laid-Open No. Hei 1-304322 is known.

[0003] This device comprises a transmitting section for transmitting an ultrasonic wave of 400 to 1500 KHz into a liquid in which a floating foreign substance forms an interface and is suspended, a receiving section for receiving a reflected wave thereof, and amplifies the received signal. And a measurement unit for measuring the interface depth based on the reflection time, attenuation, etc., and is used as shown in FIG.

[0004] As shown in FIG. 7, a sedimentation tank 120 as an interface measurement object is formed so as to have a volume commensurate with the amount of wastewater, sewage, etc. to be treated, and has a depth for wastewater treatment. Is 10 m, and 4 to 5 m for sewage treatment. The bottom is formed in a funnel shape, the suction port of the drawing pump 121 is opened at the center of the bottom, and the supernatant liquid discharge pipe 12 is provided at the top.
2 are connected. The transducer 123 is provided in the settling tank 12.
It is arranged on the liquid level within 0 (possible even at the liquid level),
A 500 KHz ultrasonic wave is transmitted into the liquid, and a reflected wave reflected at the interface between the liquid and the sludge is received and transmitted to the measuring device 124. Then, the measuring device 124 discriminates the interface signal from the reflected signal, measures the time from the transmission to the reception, the attenuation of the reflected wave, and based on these, determines the position of the sludge interface, that is, the depth from the liquid surface. Calculate.

When the sludge interface is measured by the above apparatus, the ultrasonic frequency is appropriately selected and used depending on the type of sludge such as sewage sludge, papermaking sludge, and broiler sludge. Incidentally, it is considered that the above-mentioned frequency in the range of 400 to 1500 KHz is appropriate as an ultrasonic wave that can be used when measuring the interface of sludge.

That is, as shown in FIG. 8, transducers 123a and 123b for transmitting ultrasonic waves having different frequencies and measuring circuits 124a and 124b for measuring respective signals are prepared. FIG. 8 shows two transducers 123a and 123b.
Shows a state in which both are set in advance, but usually,
The reflection state of the interface, which is the object to be measured, is experimentally measured by one of the transducers 123a and 123b, and one of the transducers 123a and 123b is appropriately selected according to the measurement result. Then, measurement of the interface is performed using the good frequency.

[0007] The frequencies of these transducers are usually 1 MHz and 500 KHz, which are selected according to the object to be measured.

[0008] The above-mentioned conventional interface measuring apparatus has a problem that it is expensive because it is necessary to prepare two or more transmitters and receivers having different frequencies as sensors. Moreover, as described above, usually, first, a single transducer selected according to the situation at the site is installed and measured, and when a good reflected signal is not obtained as a result of the measurement, the second different frequency is used. There is an inconvenience that new installation work must be performed in order to change to the transmitter / receiver of the present invention.

In order to solve the problems of the prior art, an interface measuring device having the following configuration has been proposed by the present applicant (Japanese Patent Application No. 3-42246).

That is, in consideration of the fact that the ultrasonic wave emitted from one transmitter / receiver includes not only its fundamental frequency but also an odd number (3, 5,...) Times the fundamental frequency, this one transceiver A signal based on reflected waves of two or more different frequencies which are emitted from a wave reflector, reflected at an interface and incident on the transducer, are selected by a receiving circuit, and each of the selected signals is automatically selected and switched. The optimum signal is selected from the switched received signals by the signal processing operation circuit and output. Like this one
Since the interface measurement of various kinds of sludge can be dealt with with only one transducer, it is inexpensive, and the installation work of the transducer is required only once.

[0011]

However, in any of the various interface measuring devices described above, sludge or the like adheres to the transmitting / receiving surface of the transmitter / receiver, and as shown by a solid line A in FIG. There is a drawback that the level (sensitivity) is lower than when there is no deposit (indicated by a two-dot chain line B in the figure). In such a case, it is easy to mistakenly recognize the bottom surface of the bath as an interface instead of the position of the original interface, and severely, even a received signal cannot be obtained, resulting in an unmeasurable state.
Note that the higher the frequency used for the measurement, the smaller the amplitude and the lower the energy, so that this phenomenon becomes remarkable.

In view of the above, the present invention has been made in view of the above-mentioned disadvantages of the related art, and has as its object to provide a transducer and an interface measuring device capable of always performing reliable measurement.

[0013]

SUMMARY OF THE INVENTION The present invention is directed to transmitting and receiving ultrasonic waves.
One transducer for transmitting and receiving, and ultrasonic waves by the transducer
Oscillates and receives the reflected wave.
Two or more different frequencies from the frequencies contained in the
Receiving circuit to be selected, and two or more selected by the receiving circuit.
Switching means for switching a received signal having different frequencies
Among the received signals switched by the switching means.
An arithmetic control circuit that selects appropriate signals and performs arithmetic processing
The one transducer is an ultrasonic wave of a fundamental frequency.
And an ultrasonic wave having a frequency different from the fundamental frequency.
Sludge that can be measured and is transmitted to the transmitting / receiving surface of the transducer
It has means for preventing adhesion of substances such as
You. Further, the attachment preventing means is provided to cover the wave transmitting / receiving surface.
Dome-shaped member. In addition, the present invention
Measurement is made in the room formed by the receiver and the dome-shaped member.
A medium for transmitting sound that has almost the same physical properties as a constant fluid
It is filled. In addition, the above-mentioned attachment preventing means
Has fluid ejecting means for ejecting a cleaning fluid. Ma
The adhering substance preventing means may be configured to excite the transducer.
It has a vibration means. Further, the attached matter preventing means may be a device to be measured.
The apparatus has jet generating means for jetting a fluid. In addition,
The kimono preventing means has a wiping means for wiping the sludge or the like.
You. In addition, the present invention provides a method for controlling
The stages operate in conjunction with each other.

[0014]

Next, an embodiment of the present invention will be described.

FIGS. 1 to 3 show a first embodiment of a transducer for measuring the interface of a suspended foreign substance and an interface measuring apparatus provided with the same.

As shown in FIG. 1, a wave transmitter / receiver 1 as a sensor is disposed on a liquid surface of a settling tank (even in a liquid surface), oscillates an ultrasonic wave and receives a reflected wave thereof.
The transducer 1 is composed of one vibrator, and this vibrator can transmit and receive two or more different frequencies. This utilizes the characteristics of the vibrator. For example, by using a vibrator that oscillates ultrasonic waves at a fundamental frequency of 350 KHz (basic frequency), a frequency of 1050 KHz, which is three times the frequency, is used. Can be transmitted and received simultaneously. Note that odd multiples of the fundamental frequency (350 KHz), that is, 1, 3,
Any frequency, such as 5 times, can be transmitted and received, but for practical reasons, a frequency of up to 3 times is preferable because the amplitude decreases as the frequency increases. Here, the accuracy at present is assumed to be about ± 1.0%. The selection of the fundamental frequency is not limited to this, and any frequency can be selected. In this embodiment, the frequency serving as the measurement point is about 400 KHz to 1 MK.
Hz, the frequency is set to include these frequencies.

350 transmitted by the transducer 1
The two types of ultrasonic waves, KHz and 1050 KHz, are reflected at the interface between the liquid and the sludge and enter the transducer 1.
As shown in FIG. 2, the reflected signal is output to the automatic frequency selection switch 3 via the connection cable 2 and via the receiving circuits 4 and 5.

The receiving circuit 4 is composed of a filter or the like, and receives a relatively low frequency, in this case, a frequency of 350 KHz, which is a fundamental frequency, and outputs it to the automatic frequency selection switching unit 3, that is, switching means. The receiving circuit 5
A frequency of 1050 KHz, which is three times the fundamental frequency, is received and output to the automatic frequency selection switch 3. The frequency automatic selection switch 3 inputs a signal composed of these two frequencies to the signal processing operation circuit 6 based on the switching signal S output from the signal processing operation circuit 6 as an operation control circuit. The signal processing operation circuit 6 is composed of a microcomputer or the like, and has a frequency of 350 kHz and a frequency of 1050 kHz.
By discriminating which signal with the frequency of z is the optimal interface signal, the time from transmission to reception or the degree of attenuation of the reflected wave is measured based on the optimal interface signal, and based on this, the sludge interface is determined. , Ie, the depth from the liquid level is calculated. The transmission circuit 7 is a circuit for transmitting ultrasonic waves at a fundamental frequency of 350 KHz.

With the above configuration, 1
It is possible to transmit and receive two or more types of frequencies using two transducers, and in the case where two or more transducers must be prepared conventionally, it is possible to respond with one transducer. it can.

Here, the attached matter preventing means which is added to the above-mentioned wave transmitter / receiver 1 and prevents sludge or the like from adhering to the wave transmitting / receiving surface of the wave transmitter / receiver 1 will be described with reference to FIG.

As shown, the transmitting / receiving wave surface 1a of the transmitter / receiver 1
Is covered with a dome-shaped member 11 made of synthetic resin or rubber and capable of transmitting ultrasonic waves sufficiently. By providing the dome-shaped member 11, adhesion of sludge or the like to the wave transmitting / receiving surface 1a is prevented. Although the gas generated from the lower sediment rises as bubbles 12, it is not blocked by the dome-shaped member 11 and adheres to the wave transmitting / receiving surface 1a. Further, as shown in the figure, due to the hemispherical shape of the dome-shaped member 11, this bubble 12
It rises smoothly along the surface of the surface, and adhesion to the surface is also prevented. The room formed by the transducer 1 and the dome-shaped member 11 is filled with a fluid to be measured, in this case, a sound transmission medium 11a having the same physical properties as water. The medium 11a is, for example, pure water. When the fluid to be measured is oil instead of water as described above, or is a gas such as a gas, it is appropriately selected according to the fluid.

On the other hand, the cable 2 connected to the transducer 1
A pipe 14 for guiding water as a cleaning fluid is inserted into the pipe. The washing water is stored in a storage tank (not shown), and is pressurized by a pressurizing pump 16.
It is supplied via a valve 17. The guide tube 15 is bent at its distal end, and
And is directed toward the tip of the dome-shaped member 11. A nozzle 19 for injecting water for washing is attached to the tip.

The above-mentioned storage tank, the guide tube 15, the pressurizing pump 16, the valve 17, the packing 18, and the nozzle 19 constitute cleaning water jetting means, that is, fluid jetting means.

Although both the washing water jetting means and the above-mentioned dome-shaped member 11 function as the above-mentioned attached matter preventing means, it is also possible to provide only one of the two. However, when only the above-mentioned washing water injection means is provided, the nozzle 19 is arranged toward the wave transmitting / receiving surface 1a of the wave transmitter / receiver 1.

The above-mentioned washing water injection means is operated in conjunction with the operation of the transducer 1. That is, the valve 17 is formed of, for example, an electromagnetic valve, and the valve 17 automatically opens and closes upon receiving a contact signal from the transducer 1, or conversely, transmits and receives a signal based on the contact signal from the valve 17. The vessel 1 is operated.

In this embodiment, water is used for cleaning. However, the cleaning fluid may be, for example, water mixed with chemicals or compressed air, depending on the object to be cleaned. Are appropriately selected.

In this embodiment, the receiving circuits 4 and 5 are configured to receive two types of frequencies. However, when three or more types of frequencies are received, a corresponding number of receiving circuits are used. May be provided, and the measuring apparatus of the present embodiment may be appropriately used in a general flow meter. Further, in this embodiment, the switching signal S output from the signal processing operation circuit 6 acts so as to alternately switch so that the respective reception signals of the receiving circuits 4 and 5 can be obtained. When an optimum signal is obtained, the configuration may be such that the signal is switched and fixed to the receiving circuit side where the optimum signal is obtained.

FIG. 4 shows a main part of an interface measuring apparatus according to a second embodiment of the present invention. Since the interface measuring apparatus is configured in the same manner as the interface measuring apparatus as the first embodiment shown in FIGS. 1 to 3 except for the parts described below, the description of the entire apparatus is omitted. Only the main part will be explained. Further, in the following description, the same reference numerals are used for the same components as those of the interface measuring device of the first embodiment. The same applies to the other embodiments described later.

As shown in FIG. 4, in the interface measuring device, a vibrator 31 vibrating at a predetermined frequency is attached to a pipe 14 connected to the transducer 1. An oscillator 32 for vibrating the vibrator 31 is provided, and both are connected by a cable 33. The vibrator 31 and the oscillator 32 constitute an exciting unit that excites the transducer 1. The excitation means, together with the dome-shaped member 11 covered on the wave transmitting / receiving surface 1a of the wave transmitter / receiver 1, functions as an attached matter preventing means. The dome-shaped member 11 may not be provided.

In this configuration, the transducer 1 is excited by the vibrator 31 being driven by the oscillator 32 to vibrate. Therefore, adhesion of sludge or the like is prevented.

It is preferable that the oscillator 32 is operated in conjunction with the operation of the transducer 1. In the present embodiment, the vibrator 31 is attached to the pipe 14, but may be attached to the transducer 1 directly or via a bracket (not shown).

FIG. 5 shows a main part of an interface measuring apparatus according to a third embodiment of the present invention.

As shown in the figure, in the apparatus, the deposit preventing means includes a screw propeller 41 and a motor 42 for driving the screw propeller 41 to rotate. These screw propeller 41 and motor 42 are
Collectively referred to as jet generating means. The motor 42 is connected to the pipe 1
4 is attached via a bracket 43. The supply of power to the motor 42 is controlled by the pipe 14.
This is performed through a cable (not shown) connected to the motor 42 through the inside.

In the above-described configuration, the screw propeller 41 is driven to rotate by the motor 42, so that a jet flows in the fluid to be measured, thereby preventing sludge and the like from adhering. Note that the motor 42 is also used for the transducer 1.
It is preferable to operate in conjunction with the operation of.

FIG. 6 shows a main part of an interface measuring apparatus according to a fourth embodiment of the present invention.

As shown in the figure, in the apparatus, a geared motor 52 is attached to a pipe 14 via a bracket 51, and an elongated and arc-shaped arm 53 is attached to an output shaft 52a of the geared motor 52 at one end thereof. It is fixed. Power is supplied to the geared motor 52 through a cable (not shown) connected to the geared motor 52 through the pipe 14.

The arm 53 extends along the curved surface of the dome-shaped member 11, and is reciprocated in a direction perpendicular to the plane of the drawing by the operation of the geared motor 52.

A brush 55 is implanted on the inner surface of the arm 53, and the brush 55 is reciprocated by the arm 53.
Is configured to wipe off the surface of the dome-shaped member 11 and acts as an adhesion preventing means for preventing adhesion of sludge or the like. Note that the geared motor 52, the arm 53, and the brush 55 are collectively referred to as wiping means. It is preferable that the geared motor 52 is also operated in conjunction with the transducer 1. Further, the geared motor 52 may be operated periodically.

[0039]

As described above, according to the present invention, the adhesion of sludge, bubbles, etc. to the transmitting / receiving surface of the transmitter / receiver is prevented. There is an effect that the position of can be always reliably measured. Note that this effect is particularly remarkable in a measurement using a relatively high frequency ultrasonic wave which is easily affected and attenuated due to the attachment due to small energy.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an apparatus for measuring an interface of suspended foreign matter as a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a detection circuit of the apparatus for measuring the interface of suspended foreign matter as a first embodiment of the present invention;

FIG. 3 is a vertical cross-sectional view of a wave transmitter / receiver provided in the interface measuring device shown in FIGS. 1 and 2 and an attached matter preventing means added thereto.

FIG. 4 is a longitudinal sectional view of a main part of an interface measuring device according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view of a main part of an interface measuring device according to a third embodiment of the present invention.

FIG. 6 is a longitudinal sectional view of a main part of an interface measuring device according to a fourth embodiment of the present invention.

FIG. 7 is a diagram showing the configuration of a conventional apparatus for measuring the interface of suspended foreign matter.

FIG. 8 is a diagram showing a state in which a transmitter / receiver of a conventional apparatus for measuring the interface of suspended foreign matter is installed.

FIG. 9 is a diagram showing a received signal level in a conventional apparatus for measuring the interface of suspended foreign matter.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Transmitter / receiver 1a Transmitter / receiver surface 2 Connection cable 3 Automatic frequency selection switching device (switching means) 4, 5 Receiving circuit 6 Signal processing operation circuit (Operation control circuit) 7 Transmission circuit 11 Dome member 11a Sound transmission medium 14 Pipe 15 Guide tube 16 Pressure pump 17 Valve 18 Packing 19 Nozzle 31 Vibrator 32 Oscillator 41 Screw propeller 42 Motor 52 Geared motor 53 Arm 54 Brush

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigeyuki Kawanobe 3-1-5 Sakaemachi, Hamura-shi, Tokyo Kaijo Co., Ltd. (56) References JP-A-60-125524 (JP, A) JP-A-55-57115 (JP, A) JP-A-1-105121 (JP, A) JP-A-2-68594 (JP, U) JP-A 1-111783 (JP, U) JP-A-60-1009064 (JP, U) ( 58) Surveyed field (Int.Cl. ⁶ , DB name) G01F 23/28 G01B 17/00 G01S 7/521

Claims (8)

(57) [Scope of request for utility model registration] 1. A single transducer for transmitting and receiving ultrasonic waves
And an ultrasonic wave oscillated by the transducer and a reflected wave thereof.
And from the frequency contained in this received signal
A receiving circuit for selecting two or more different frequencies, and two or more different frequencies selected by the receiving circuit .
And switching means for switching the Ranaru received signal, optimum among the received signals switched by said switching means
An arithmetic control circuit for selecting a signal and performing arithmetic processing, wherein the one transducer is an ultrasonic wave having a fundamental frequency;
Measuring the ultrasonic frequency having a frequency different from the basic frequency
It is possible to prevent adhesion of sludge and the like to the transmitting and receiving surface of the transmitter and receiver.
Of suspended foreign matter, characterized by having
Interface measurement device. 2. The apparatus according to claim 1, wherein the attachment preventing means is provided on the wave transmitting / receiving surface.
Claims characterized by having an overlying dome-shaped member
Item 4. An interface measuring device for suspended foreign matter according to Item 1. 3. The apparatus according to claim 3, wherein said transducer and said dome-shaped member are provided.
In the formed chamber, physical properties almost equivalent to the fluid to be measured
Characterized by being filled with a sound transmission medium having
The apparatus for measuring an interface of suspended foreign matter according to claim 2. 4. The method according to claim 1, wherein the deposit preventing means includes a cleaning fluid.
And a fluid ejecting means for ejecting the fluid.
The apparatus for measuring an interface of suspended foreign matter according to claim 1. 5. The apparatus according to claim 1, wherein the adhering substance preventing means includes a transmitter and a receiver.
2. The apparatus according to claim 1, further comprising: an exciting means for exciting.
Interface measuring device for suspended foreign substances. 6. The method according to claim 1, wherein the adhering substance preventing means injects a fluid to be measured.
A jet generating means for causing the jet to flow.
The apparatus for measuring an interface of suspended foreign matter according to claim 1. 7. The deposit preventing means removes the sludge or the like.
2. A wiping means for wiping is provided.
Interface device for suspended foreign substances. 8. The apparatus according to claim 1, wherein the transducer and the attached matter preventing means are arranged alternately.
2. The apparatus according to claim 1, wherein the apparatus operates in conjunction with the operation.
Interface measuring device for suspended foreign substances.