JPH0564715U - Transducer / receiver for interface measurement of suspended foreign matter and interface measuring device equipped with the transceiver - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a wave transmitter / receiver capable of constantly and accurately measuring the interface of suspended foreign matter in sludge and the like, and an interface measuring device equipped with the wave transmitter / receiver. [Structure] Adhesion preventing means 1 for preventing adhesion of sludge or the like to a wave transmitting / receiving surface 1a of a wave transmitting / receiving device 1 for transmitting / receiving ultrasonic waves
1, 19, ...

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is directed to a settling tank for wastewater treatment, sewage treatment, and the like, and a transducer for emitting ultrasonic waves toward the interface of foreign matter that forms an interface and is suspended in a liquid, and measures the position of the interface. The present invention relates to an interface measuring device equipped with the transducer.

[0002]

[Prior Art]

 Conventionally, as this type of transmitter / receiver and interface measuring device, one disclosed in Japanese Patent Laid-Open No. 1-304322 is known.

This device is composed of a transmitter 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 receiver for receiving a reflected wave thereof, and a received signal. Is provided to discriminate the interface signal and to measure the depth of the interface based on the reflection time, the attenuation, etc., and is used as shown in FIG.

As shown in FIG. 7, the settling tank 120, which is an object of interface measurement, has a volume formed to correspond to the amount of wastewater to be treated, sewage, etc. In the case of sewage treatment, it is 10 m, and in the case of sewage treatment it is 4 to 5 m. The bottom is formed in a funnel shape, the suction port of the drawing pump 121 is opened in the center of the bottom, and the supernatant liquid discharge pipe 122 is provided in the upper part. Are connected. The wave transmitter / receiver 123 is disposed on the liquid surface in the settling tank 120 (even in the liquid surface), transmits ultrasonic waves of 400 to 1500 KHz into the liquid, and is reflected at the interface between the liquid and the sludge. The wave is received and transmitted to the measuring device 124. Then, the measuring device 124 discriminates the interface signal from the reflection signal, measures the time from the transmission to the reception, the attenuation of the reflected wave, and based on these, the position of the sludge interface, that is, the depth from the liquid surface. Is calculated.

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

That is, as shown in FIG. 8, wave transmitters / receivers 123a and 123b for transmitting ultrasonic waves of different frequencies and measurement circuits 124a, 124b for measuring respective signals are prepared. Although FIG. 8 shows a state in which both the wave transmitters / receivers 123a and 123b are installed in advance, usually, the interface of the object to be measured is measured by either one of the wave transmitters / receivers 123a or 123b. The reflection state is measured on a trial basis, which of the transmitters / receivers 123a and 123b is selected as the optimum frequency according to the measurement result, and the interface is measured at the favorable frequency.

As the frequencies of these transmitters / receivers, those of 1 MHz and 500 KHz are usually used, and they are selected and used according to the object to be measured.

By the way, in the above-mentioned conventional interface measuring apparatus, since it is necessary to prepare two or more wave transmitters / receivers having different frequencies as sensors, there is a problem that it is expensive. Moreover, as described above, usually, one transducer is selected according to the situation at the site, and measurement is performed. If 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 done to change to the other transducer.

Therefore, in order to solve the problems of the conventional technique, the applicant of the present application has proposed an interface measuring device having the following configuration (Japanese Patent Application No. 3-42246).

That is, in view 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, ...) Multiple of the fundamental frequency, The receiving circuit selects signals based on the reflected waves of two or more different frequencies which are emitted from the wave transmitter and reflected at the interface and are incident on the wave receiver, and the selected signals are automatically selected by frequency. The signal is switched by the switch, and the optimum signal among the switched received signals is selected and output by the signal processing arithmetic circuit. In this way, since only one wave transmitter / receiver can deal with the interface measurement of various sludges, it is inexpensive and the installation work of the wave transmitter / receiver only needs to be done once.

[0011]

[Problems to be solved by the device]

 However, in any of the various interface measuring devices described above, sludge or the like adheres to the transmitting / receiving surface of the transducer, and as shown by the solid line A in FIG. There is a drawback that the value is lower than that of the case where there is no (shown by a chain double-dashed line B in the figure). In such a case, it is easy to misunderstand that the bottom surface of the tank is the interface, not the original position of the interface, and even the received signal cannot be obtained, resulting in an unmeasurable state. It should be noted that the higher the frequency used for measurement, the smaller the amplitude and the less energy, so that this phenomenon becomes more prominent.

Therefore, the present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object of the present invention is to provide a transducer and an interface measuring device capable of always performing reliable measurement.

[0013]

[Means for Solving the Problems]

 The present invention is a transducer that is used for measuring the interface of suspended foreign matter and transmits and receives ultrasonic waves, and is equipped with a deposit prevention means for preventing the attachment of sludge to the transmitting and receiving surface. .. In addition, the present invention provides a single transmitter / receiver for transmitting and receiving ultrasonic waves, oscillating ultrasonic waves by the transmitter / receiver, and receiving a reflected wave thereof, and transmitting two or more different frequencies of the received signal. The receiving circuit to be selected, the switching means for switching the receiving signals having two or more different frequencies selected by the receiving circuit, and the optimum signal among the receiving signals switched by the switching means is selected and calculated. An interface measurement of suspended foreign matter, which is provided with a processing control circuit for processing and is configured to be able to measure a basic frequency of the ultrasonic wave received by the transducer and a frequency different from the basic frequency. The device is provided with an adhered substance preventing means for preventing adherence of sludge or the like to the wave transmitting / receiving surface of the wave transmitter / receiver.

[0014]

【Example】

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

FIG. 1 to FIG. 3 show a transducer for measuring the interface of suspended foreign matter and an interface measuring apparatus equipped with the same as a first embodiment of the present invention.

As shown in FIG. 1, a wave transmitter / receiver 1 as a sensor is arranged on the liquid surface of the settling tank (even in the liquid surface), and oscillates ultrasonic waves and receives the reflected waves thereof. .. The transceiver 1 is composed of one oscillator, and this oscillator can transmit and receive two or more different frequencies. This utilizes the characteristics of the oscillator. For example, by using an oscillator that oscillates an ultrasonic wave of the basic frequency of 350 KHz (fundamental frequency), the frequency of 1050 KHz, which is three times the frequency of this, is used. A number of ultrasonic waves can be transmitted and received at the same time. Note that it is possible to send and receive any frequency that is an odd multiple of the fundamental frequency (350 KHz), that is, 1, 3, 5, ..., but for the reason that the amplitude decreases as the frequency increases. Therefore, practically up to three times as much is preferable. Here, the current accuracy is ± about 1.0%. The selection of the fundamental frequency is not limited to this, and it is possible to select any frequency, but in the present embodiment, the frequency at the measurement point is about 400 KHz to 1 MKHz, and therefore these frequencies are selected. It is designed to include frequencies.

Two types of ultrasonic waves of 350 KHz and 1050 KHz transmitted by the wave transmitter / receiver 1 are reflected at the interface between the liquid and the sludge, and enter the wave transmitter / receiver 1. As shown in FIG. 2, this reflected signal is output to the frequency automatic 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, receives a relatively low frequency, in this case, a frequency of 350 KHz which is a basic frequency, and outputs it to the automatic frequency selection switch 3 or switching means. To do. The receiving circuit 5 receives the frequency of 1050 KHz, which is three times the fundamental frequency, and outputs it to the automatic frequency selection switch 3. The frequency automatic selection switch 3 inputs a signal having both of these 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 arithmetic circuit 6 is composed of a microcomputer and the like, discriminates which signal of the frequency of 350 KHz and the frequency of 1050 KHz is the optimum interface signal, and receives from the transmission by the optimum interface signal. Or the attenuation of the reflected wave is measured, and the position of the sludge interface, that is, the depth from the liquid surface is calculated based on this. The transmission circuit 7 is a circuit for transmitting ultrasonic waves at a basic frequency of 350 KHz.

With the above-described configuration, it is possible to transmit and receive two or more types of frequencies using one transceiver, and conventionally two or more transceivers must be prepared. Even in such a case, it is possible to deal with it with one transmitter / receiver.

Here, a description will be given with reference to FIG. 3 of the attached matter preventing means which is added to the above-mentioned wave transmitter / receiver 1 and prevents adhesion of sludge or the like to the wave transmitting / receiving surface of the wave transmitter / receiver 1.

As shown in the figure, the wave transmitting / receiving surface 1a of the wave transmitting / receiving device 1 is covered with a dome-shaped member 11 made of synthetic resin, rubber or the like and capable of sufficiently transmitting ultrasonic waves. By providing the dome-shaped member 11, the attachment of sludge or the like to the wave transmitting / receiving surface 1a is prevented. The gas generated from the lower precipitate rises as bubbles 12 but 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, the bubbles 12 rise smoothly along the surface of the dome-shaped member 11 and are prevented from adhering to the surface. A chamber formed by the wave transmitter / receiver 1 and the dome-shaped member 11 is filled with a sound wave transmission medium 11a having physical properties equivalent to those of the fluid to be measured, in this case water. The medium 11a is, for example, pure water, and when the fluid to be measured is not water as described above but oil or gas such as gas, it is appropriately selected according to them.

On the other hand, a pipe 14 is provided so as to cover the cable 2 connected to the wave transmitter / receiver 1, and a guide tube 15 for guiding water as a cleaning fluid is inserted into the pipe 14. There is. The cleaning water is stored in a storage tank (not shown), pressurized by the pressure pump 16, and supplied through the valve 17. The guide tube 15 has its front end bent so as to be projected to the outside of the pipe 14 through the packing 18 and is directed toward the tip of the dome-shaped member 11. A nozzle 19 for spraying cleaning water is attached to the tip.

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

Although both the cleaning water jetting means and the above-mentioned dome-shaped member 11 act as the above-mentioned adhering matter preventing means, only one of them may be provided. However, when only the cleaning water jetting means is provided, the nozzle 19 is arranged toward the wave transmission / reception surface 1 a of the wave transceiver 1.

The above-mentioned cleaning water jetting means is operated in conjunction with the operation of the wave transmitter / receiver 1. That is, the valve 17 is composed 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, based on the contact signal from the valve 17. The transmitter / receiver 1 is adapted to operate.

In this embodiment, water is used for cleaning, but the cleaning fluid may be water mixed with chemicals or compressed air, depending on the object to be cleaned. Items are selected as appropriate.

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

FIG. 4 shows a main part of an interface measuring apparatus as a second embodiment of the present invention. 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 portions described below, and therefore the description of the apparatus as a whole is omitted. However, I will only explain the main parts. Further, in the following description, the same reference numerals are used for the same constituent members as those of the interface measuring apparatus of the first embodiment. Moreover, the same applies to other embodiments described later.

As shown in FIG. 4, in the interface measuring apparatus, a vibrator 31 vibrating at a predetermined frequency is attached to the pipe 14 coupled 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 means for exciting the transducer 1. The excitation means works together with the dome-shaped member 11 covered on the wave transmission / reception surface 1a of the wave transmitter / receiver 1 as an adhering matter prevention means. The dome-shaped member 11 may not be provided.

In such a configuration, the transducer 31 is driven by the oscillator 32 to vibrate, and thus the transducer 1 is excited. Therefore, adhesion of sludge and the like is prevented.

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

FIG. 5 shows an essential part of an interface measuring apparatus as 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 that rotationally drives the screw propeller 41. These screw propeller 41 and motor 42 are collectively referred to as a jet flow generating means. The motor 42 is attached to the pipe 14 via a bracket 43. Power is supplied to the motor 42 through a cable (not shown) connected to the motor 42 through the pipe 14.

In the above configuration, the screw propeller 41 is rotationally driven by the motor 42, so that a jet flow is generated in the fluid to be measured, which prevents the attachment of sludge and the like. The motor 42 is also preferably operated in conjunction with the operation of the wave transmitter / receiver 1.

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

As shown in the figure, in the apparatus, a gear motor 52 is attached to the pipe 14 via a bracket 51, and an elongated arm 53 formed in an arc shape is attached to an output shaft 52a of the geared motor 52 at one end thereof. It is fixed in. Further, the power supply to the geared motor 52 is performed 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 can be reciprocated in the direction perpendicular to the paper surface by the operation of the geared motor 52.

A brush 55 is implanted on the inner surface side of the arm 53, and the brush 55 wipes the surface of the dome-shaped member 11 by the reciprocating movement of the arm 53. It acts as a means for preventing deposits. The geared motor 52, the arm 53, and the brush 55 are collectively referred to as wiping means. The geared motor 52 described above is also preferably operated in conjunction with the wave transmitter / receiver 1. Moreover, the geared motor 52 may be operated periodically.

[0039]

[Effect of the device]

 As described above, according to the present invention, since the adhesion of sludge and bubbles to the wave receiving / transmitting surface of the wave transmitter / receiver is prevented, the received signal level does not decrease and the position of the interface is always ensured. There is an effect that can be measured. It should be noted that this effect is particularly remarkable in the measurement using ultrasonic waves of a relatively high frequency which are easily attenuated due to the influence of deposits due to the small energy.

[Brief description of drawings]

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

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

FIG. 4 is a vertical cross-sectional view of a main part of an interface measuring device as a second embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a main part of an interface measuring apparatus as a third embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of a main part of an interface measuring apparatus as a fourth embodiment of the present invention.

FIG. 7 is a diagram showing a structure of a conventional interface measuring device for suspended foreign matter.

FIG. 8 is a view showing a state in which a wave transmitter / receiver of a conventional interface for measuring a foreign matter in suspension is installed.

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

[Explanation of sign]

 DESCRIPTION OF SYMBOLS 1 Transducer / receiver 1a Transmission / reception surface 2 Connection cable 3 Frequency automatic selection switching device (switching means) 4,5 Reception circuit 6 Signal processing arithmetic circuit (arithmetic control circuit) 7 Transmission circuit 11 Dome-shaped member 11a Sound wave transmission medium 14 Pipe 15 Guide tube 16 Pressurizing pump 17 Valve 18 Packing 19 Nozzle 31 Oscillator 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 Inside Kaijo Co., Ltd.

Claims (9)

[Scope of utility model registration request] 1. A transmitter / receiver that is used for interface measurement of suspended foreign matter and transmits / receives ultrasonic waves, characterized in that the transmitter / receiver is provided with an adhered substance preventing means for preventing adhesion of sludge or the like to the transmitting / receiving surface. Wave instrument. 2. The transducer according to claim 1, wherein the deposit preventing means has a dome-shaped member provided on the transmitting and receiving surface. 3. A sound transmission medium having substantially the same physical properties as the fluid to be measured is filled in the chamber formed by the wave transmitter / receiver and the dome-shaped member. The transducer according to 2. 4. The wave transmitter / receiver according to claim 1, wherein the adhering substance preventing unit includes a fluid ejecting unit that ejects a cleaning fluid. 5. The wave transmitter / receiver according to claim 1, wherein the adhering substance preventing means has an exciting means for exciting the wave transmitter / receiver. 6. The transducer according to any one of claims 1 to 5, wherein the deposit preventing means has a jet generating means for causing a fluid to be measured to generate a jet. 7. The wave transmitter / receiver according to claim 1, wherein the adhering matter preventing unit has a wiping unit that wipes the sludge and the like. 8. A single wave transmitter / receiver for transmitting and receiving ultrasonic waves, and oscillating an ultrasonic wave by the wave transmitter / receiver and receiving a reflected wave thereof, and selecting two or more different frequencies of the received signal. A receiving circuit, a switching means for switching a received signal having two or more different frequencies selected by the receiving circuit, and an operation for selecting an optimum signal from the received signals switched by the switching means and performing arithmetic processing. And a control circuit, which is configured so that the frequency of the ultrasonic wave received by the transducer can be measured as a basic frequency and a frequency different from the basic frequency, and the sludge on the wave-receiving surface of the transducer can be measured. An interface measuring device for suspended foreign matter, which is provided with an adhesion preventing means for preventing the adhesion of the like. 9. The apparatus for measuring the interface of suspended foreign matter according to claim 8, wherein the wave transmitter / receiver and the adhering matter preventing means are interlocked with each other.