JP4741279B2 - Sludge interface measuring device - Google Patents

Description

  The present invention relates to a sludge interface measuring apparatus, and more particularly to a sludge interface measuring apparatus that can improve the reliability of measurement data.

  Sewage treatment plants are equipped with sewage treatment tanks. In the sewage treatment tank, sludge settles at the bottom, and the supernatant liquid accumulates thereon. However, when sewage flows continuously into the sewage treatment tank, the amount of sludge sedimentation increases, and the supernatant liquid The interface between the part and the precipitated sludge part will rise.

  When the amount of sludge sedimentation increases, it is necessary to discharge the sludge from the sewage treatment tank at a certain stage, and therefore the position of the interface needs to be constantly monitored.

  The interface position is generally measured by a measuring device, but ultrasonic waves or the like are often used for the measurement. That is, the interface position is measured by measuring the time until the reflected wave returns by applying ultrasonic waves or the like to sludge.

However, a sludge scraper or a scraper is generally disposed in the lower part of the sewage treatment tank. When the ultrasonic wave is applied to sludge, the scraper or the scraper May be mixed with measurement data as shown in the graph of FIG. 5 by moving to the measurement point and reflecting the ultrasonic wave or the like against the scraper or scraper. .
In the graph of FIG. 5, part A shows the measured value of the sludge interface, and part B shows the measured value when the scraper is hit by ultrasonic waves. Moreover, C part has shown the state which the sludge interface fell by the waste mud.

  As a result, the measurement data becomes unclear, the accurate sludge interface position cannot be measured, and the reliability of the measurement data is impaired.

In order to solve the above problems, a sludge interface monitoring device as described in Patent Document 1 has been proposed.
Japanese Patent No. 3352853

  However, the above-mentioned sludge interface monitoring device states that “the first delayed interface signal and the second delayed interface signal obtained by delaying the interface signal based on the received signal reflected by the sludge interface or the scraper in at least two stages. And a memory circuit that stores the first delay interface signal and the second delay interface signal stored in the storage circuit and the current interface signal by the received signal, and at the time of monitoring When the absolute value in the comparison result between the current interface signal and the first delay interface signal and the second delay interface signal is both smaller than a predetermined value, and one of them is large and the other is small When the current interface signal is output, the absolute value in the comparison result between the current interface signal and the first delayed interface signal and the second delayed interface signal is greater than a predetermined value. When there is Serial has a configuration in which a comparison circuit "for outputting the first delay interface signal or the second delay interface signal, a complicated processing operation and configuration, there is a problem that increase the manufacturing cost.

  Therefore, an object of the present invention is to prevent measurement values obtained by reflection of ultrasonic waves or the like on the scraper or scraper from being mixed with measurement data at the sludge interface position, and accurate measurement data. It is another object of the present invention to provide a sludge interface measuring apparatus that can avoid the increase in manufacturing cost due to the complexity of the apparatus.

In order to solve the above-mentioned problem, the sludge interface measuring device according to the present invention described in claim 1 is capable of measuring the interface position of the precipitated sludge section with respect to the supernatant liquid section at a predetermined position in the sewage treatment tank, when the sewage sludge scraping device is movably disposed within a tank or the sludge raking machine has entered the measurement point of said measuring means, have a means capable of stopping the measurement of the measuring means, the The measurement stopping means of the measuring means transmits a signal instructing to stop at the timing when the sludge scraper or the sludge scraper enters the measuring point of the measuring means, and is separated from the measuring point. It is configured to be able to transmit a signal instructing restart of measurement to the measurement means at the timing of leaving, and as the measurement stop means, the sludge scraper or sludge scraper approaches the measurement point of the measurement means. And it states that, wherein the proximity switch capable of detecting a state of Hanaresa from the measurement point is used.

That is, in the sludge interface measuring apparatus according to the present invention as set forth in claim 1, the interface position between the supernatant liquid part and the precipitated sludge part is measured at the predetermined position in the sewage treatment tank by the measuring means. However, when a sludge scraper or a sludge scraper movably arranged in the sewage treatment tank enters the measurement point of the measurement means, the measurement of the measurement means is stopped. For this purpose, a measurement stop means is provided. Thereby, the measurement data obtained by the influence of the sludge scraper or the sludge scraper is excluded.
In addition, at the timing when the sludge scraper or the sludge scraper enters the measurement point of the measurement means, the measurement stop means transmits a signal instructing the measurement to stop to stop the measurement. In addition, at the timing when the sludge scraper or the sludge scraper moves away from the measurement point, the measurement is stopped by transmitting a signal instructing the measurement to be restarted by the measurement stop means. It is what is done .
Further, the proximity switch detects a state in which the sludge scraper or the sludge scraper approaches the measurement point of the measurement means, and the measurement is performed by transmitting a signal instructing the stop of the measurement to the measurement means. Measurement is performed by the proximity switch detecting a state where the sludge scraper or the sludge scraper is separated from the measurement point and transmitting a signal instructing the restart of measurement to the measurement means. Will be resumed.

  Further, the sludge interface measuring device according to the present invention described in claim 2 is configured such that when measurement of the measuring unit is stopped by the measuring stop unit, measurement data immediately before the stop is held until the measurement is restarted. It is characterized by.

  That is, in the sludge interface measuring apparatus according to the second aspect of the present invention, when measurement by the measurement unit is stopped by the measurement stop unit, a blank portion of measurement data is generated. In order to fill the part, the measurement data immediately before the stop is held until the measurement is restarted. Thereby, it can avoid that the said measurement data become discontinuous.

  Further, in the sludge interface measuring apparatus according to the present invention as set forth in claim 3, the measuring means can recognize the interface position by measuring the time from when the ultrasonic wave or the like is applied to the sludge until the reflected wave returns. It is comprised by these.

  That is, in the sludge interface measuring apparatus according to the third aspect of the present invention, from the time until the reflected wave returns after applying ultrasonic waves or the like to the sludge, and the speed of the ultrasonic waves, the sludge interface is measured. The distance can be obtained by calculation.

Further, the sludge interface measuring apparatus according to the present invention described in claim 4 is the timing at which the sludge scraper or the sludge scraper enters the measurement point of the measurement unit as the measurement stop unit, and the measurement point. A timer is used which can measure the timing of leaving the vehicle.

That is, in the sludge interface measuring apparatus according to the present invention as set forth in claim 4 , the timer detects a state in which the sludge scraper or the sludge scraper approaches the measurement point of the measuring means, and the measurement is performed. The measurement is stopped by transmitting a signal instructing to stop the operation to the measuring means, and the timer detects a state in which the sludge scraper or the sludge scraper is separated from the measurement point. The measurement is resumed by transmitting a signal instructing the resumption to the measurement means.

According to a fifth aspect of the present invention, there is provided a sludge interface measuring apparatus according to the present invention, wherein the sludge scraper or the sludge scraper is configured to be able to rotate in the sewage treatment tank.

That is, in the sludge interface measuring apparatus according to the present invention described in claim 5 , the sludge scraper or the sludge scraper is configured to be able to rotate in the sewage treatment tank. Each time the sludge scraper or the sludge scraper rotates and passes through the measurement stop means, the measurement stop means can instruct the measurement means to stop the measurement.

  According to a sixth aspect of the present invention, there is provided the sludge interface measuring apparatus according to the present invention, wherein the sludge scraper or the sludge scraper is configured to reciprocate in the sewage treatment tank.

  That is, in the sludge interface measuring apparatus according to the present invention described in claim 6, the sludge scraper or the sludge scraper is configured to reciprocate in the sewage treatment tank. Each time the sludge scraper or the sludge scraper moves back and forth and passes through the measurement stop means, the measurement stop means can instruct the measurement means to stop the measurement.

The sludge interface measuring apparatus according to the present invention as set forth in claim 1 is capable of measuring the interface position of the precipitated sludge section with respect to the supernatant liquid section at a predetermined position in the sewage treatment tank, and is movable in the sewage treatment tank. when disposed sludge scraping device or the sludge raking machine has entered the measurement point of the measurement means, have a means capable of stopping the measurement of the measuring means, the measuring stop means of said measuring means, The sludge scraper or the sludge scraper transmits a signal instructing to stop at the timing of entering the measuring point of the measuring means, and restarts the measurement at the timing of leaving the measuring point. The instructing signal can be transmitted to the measuring means, and as the measurement stopping means, the sludge scraper or the sludge scraper approaches the measuring point of the measuring means and the measuring point. Since the proximity switch capable of detecting a state in which Hanaresa is used, since the sludge scraping device or the sludge raking device is not performed measurement when entering the measurement point of the measurement means, ultrasonic The measurement data obtained by reflecting on the sludge scraper or sludge scraper is not mixed with the measurement data of the sludge interface, and accurate measurement data of the sludge interface can be obtained. Reliability is improved.
In addition, since it is only necessary to provide a means capable of stopping the measurement of the measuring means, the apparatus is not complicated and the cost is not increased.
Further, measurement stop and measurement restart of the measurement means are accurately performed by a signal transmitted from the measurement stop means to the measurement means.
Further, by simply placing the proximity switch at a predetermined position, it is possible to accurately control the measurement stop and measurement restart of the measuring means, and avoid an increase in cost due to the complexity of the apparatus.

  Further, the sludge interface measuring device according to the present invention described in claim 2 is configured such that when measurement of the measuring unit is stopped by the measuring stop unit, measurement data immediately before the stop is held until the measurement is restarted. Therefore, the blank portion of the measurement data generated when the measurement of the measurement unit is stopped by the measurement stop unit is compensated by the measurement data immediately before the stop, and the continuity of the measurement data is maintained. Will be. Accordingly, it is possible to solve the problem that the measurement data becomes incomplete.

  Further, in the sludge interface measuring apparatus according to the present invention as set forth in claim 3, the measuring means can recognize the interface position by measuring the time from when the ultrasonic wave or the like is applied to the sludge until the reflected wave returns. Therefore, the position of the sludge interface can be measured accurately and quickly.

Further, the sludge interface measuring apparatus according to the present invention described in claim 4 is the timing at which the sludge scraper or the sludge scraper enters the measurement point of the measurement unit as the measurement stop unit, and the measurement point. Since a timer that can measure the timing of moving away from the instrument is used, the measurement stop and restart of the measurement means can be accurately controlled simply by installing the timer, resulting in a complicated device. Cost increase can be avoided.

Further, in the sludge interface measuring apparatus according to the present invention described in claim 5 , since the sludge scraper or the sludge scraper is configured to be able to rotate in the sewage treatment tank, the sewage treatment layer The sludge scraper or the sludge scraper can be used only by arranging the measurement stop means at only one predetermined location in the sewage treatment tank. The measurement stop means can instruct the measurement means to stop the measurement every time it moves to the position of the measurement stop means. Therefore, it is possible to prevent the apparatus from becoming complicated and to suppress an increase in cost.

Further, in the sludge interface measuring apparatus according to the present invention described in claim 6 , the sludge scraper or the sludge scraper is configured to reciprocate in the sewage treatment tank. The sludge scraper or sludge scraper stops the measurement by simply placing the measurement stop means only at one of the predetermined locations in the sewage treatment tank. The measurement stop means can instruct the measurement means to stop the measurement every time it moves to the position of the means. Therefore, it is possible to prevent the apparatus from becoming complicated and to suppress an increase in cost.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 3, the sludge interface measuring apparatus 11 according to the present embodiment is capable of measuring the interface position of the precipitated sludge section with respect to the supernatant liquid section at a predetermined position in the sewage treatment tank 12. When the sludge scraper 16 or the sludge scraper 24 movably disposed in the sewage treatment tank 12 enters the measurement point of the measurement means 19, the measurement of the measurement means 19 can be stopped. Means.
Further, when the measurement by the measurement means 19 is stopped by the measurement stop means 21, the measurement data immediately before the stop is held until the measurement is restarted, as shown in FIG.
Further, as shown in FIGS. 1 and 3, the measuring means 19 is configured to recognize the interface position by measuring the time from applying ultrasonic waves to sludge until the reflected wave returns. Yes.
Further, as shown in FIGS. 1 and 3, the measurement stopping means 21 of the measuring means 19 is stopped when the sludge scraper 19 or the sludge scraper 24 enters the measurement point of the measuring means 19. Is sent to the measuring means 19, and a signal instructing to restart the measurement is sent to the measuring means 19 at the timing of leaving the measuring point.
As the measurement stop means 21, as shown in FIGS. 1 and 2, the sludge scraper 16 or the sludge scraper 24 approaches the measurement point of the measurement means 19 and the measurement point. A proximity switch 22 that can detect the state of separation is used.
In another embodiment, as the measurement stop unit 21, as shown in FIG. 3, the timing at which the sludge scraper 16 or the sludge scraper 24 enters the measurement point of the measurement unit 19, and the above A timer 29 that can measure the timing of leaving from the measurement point is used.
Moreover, the said sludge scraper 16 or the sludge scraper 24 is comprised so that the inside of the said sewage treatment tank 12 can be rotated, as shown in FIG.
In another embodiment, the sludge scraper 16 or the sludge scraper 24 is configured to reciprocate in the sewage treatment tank 12 as shown in FIG.

1 and 2 show a sludge interface measuring apparatus 11 according to the first embodiment.
As shown in FIG. 1, the sludge interface measuring apparatus 11 according to the first embodiment is installed in a sewage treatment tank 12 provided in a sewage treatment plant or the like.

As shown in FIG. 1, the sewage treatment tank 12 is formed in a cylindrical shape, and a supernatant discharge portion 13 is provided at the upper end portion of the side surface, and a drainage portion 14 is connected to the bottom portion. A valve 15 is attached to 14.
Moreover, although not shown in figure, the sewage injection | pouring part is provided.

  Sewage is injected into the sewage treatment tank 12 from the sewage injection section. Sludge settles at the bottom when the sewage is left unattended. Accordingly, the sewage is separated into a supernatant and sludge, and the supernatant is discharged from the supernatant discharge unit 13.

  When sewage is continuously poured into the sewage treatment tank 12, the amount of sludge sedimented increases, so if sludge accumulates to some extent, it is necessary to discharge the sludge. For this purpose, a sludge scraper 16 is provided inside the sewage treatment tank 12, as shown in FIG.

  As shown in FIG. 1, the sludge scraper 16 has a configuration in which blades 18 are provided radially on the rotating shaft 17.

The sludge is discharged when the amount of sludge set in the sewage treatment tank 12 increases and the interface position of the sludge with respect to the supernatant rises to a predetermined position. Therefore, it is necessary to constantly monitor the sludge interface position.
For this purpose, as shown in FIG. 1, the sewage treatment tank 12 is equipped with a measuring means 19 capable of measuring the interface position of the sludge.

  As shown in FIG. 1, the measuring unit 19 includes an ultrasonic wave transmitting unit 20. That is, the measuring means 19 is configured to measure the interface position by measuring the time until the reflected wave returns by applying ultrasonic waves to the sludge interface.

When the interface of sludge is measured by the measuring means 19, the blade 18 in the sludge scraper 16 moves and enters the measurement point, that is, the ultrasonic irradiation point. However, the measurement value obtained by reflecting on the blade 18 is mixed with the sludge measurement data. As a result, the measurement data of the sludge interface position is unclear, the accurate sludge interface position cannot be measured, and the reliability of the measurement data is impaired.
Accordingly, it is necessary to prevent the measurement value obtained by the ultrasonic wave from being reflected by the blade portion 18 and being mixed with the sludge measurement data.

  Therefore, when the blade portion 18 in the sludge scraper 16 movably disposed in the sewage treatment tank 12 enters the measurement point of the measurement means 19, the measurement of the measurement means 19 is stopped. Means are provided.

  The measurement stop means 21 sends a signal instructing the stop at the timing when the blade portion 18 of the sludge scraper 16 enters the measurement point of the measurement means 19, that is, the ultrasonic wave irradiation point. And a signal for instructing the restart of measurement at the timing of leaving from the measurement point.

  As the measurement stop means 21, as shown in FIGS. 1 and 2, the blade portion 18 of the sludge scraper 16 approaches the measurement point of the measurement means 19 and moves away from the measurement point. A proximity switch 22 that can detect the state is used.

  As shown in FIG. 2, a detected member 23 is provided radially at the upper end of the rotating shaft 17 so as to coincide with the blade portion 18, and the proximity switch 22 is moved closer to the detected member 23. And it is arranged at a position where it can sense separation.

When the blade portion 18 of the sludge scraper 16 approaches the measurement point of the measuring means 19, the proximity switch 22 detects the approach of the detected member 23 and stops measuring the measuring means 19. Send the instruction signal.
When the blade portion 18 of the sludge scraper 16 moves away from the measurement point of the measuring means 19, the proximity switch 22 detects the removal of the detected member 23, and the measuring means 19 A signal for instructing to resume measurement is transmitted.

  While the measurement means 19 stops measuring, measurement data cannot be obtained, and a blank portion is generated in the measurement data. Therefore, in order to prevent the measurement data from becoming discontinuous, when the measurement is stopped, the measurement unit 19 performs processing so that the measurement data immediately before the measurement stop is held until the measurement is restarted. .

Thereby, as shown in FIG. 4, the continuous measurement data without a blank part can be obtained.
In FIG. 4, part D is a part supplemented with measurement data immediately before the stop of measurement, and part A is an interface measurement value of sludge. Moreover, C part has shown the state which the sludge interface fell by the waste mud.

FIG. 3 shows a sludge interface measuring apparatus 11 according to the second embodiment.
As shown in FIG. 3, the sewage treatment tank 12 of the sludge interface measuring apparatus 11 according to the second embodiment is formed in an elongated shape.

  As shown in FIG. 3, the sewage treatment tank 12 is provided with a supernatant discharge part 13 at the upper end of the side surface and a mud discharge part 14 at one end of the bottom. Moreover, although not shown in figure, the sewage injection | pouring part is provided.

  As shown in FIG. 3, a sludge scraper 24 is provided inside the sewage treatment tank 12 in order to scrape the precipitated sludge and discharge it from the drainage section 14.

  As shown in FIG. 3, the sludge scraper 24 has a drive rotating member 25 disposed at one end of the sewage treatment tank 12 and a driven rotating member 26 disposed at the other end. A rotation transmission member 27 is wound between the rotation transmission member 26 and the driven rotation member 26, and a scraping plate portion 28 is attached to the rotation transmission member 27.

  The scraping plate portion 28 moves to the right together with the rotation transmission member 27 when the drive rotation member 25 rotates in one direction, and moves left with the rotation transmission member 27 when the drive rotation member 25 rotates in the other direction. It moves to the direction and is comprised so that it can reciprocate.

  The sewage treatment tank 12 is equipped with a measuring means 19 that can measure the interface position of the sludge, and the measuring means 19 has an ultrasonic transmission unit 20. The measuring means 19 is configured to measure the interface position by measuring the time until the reflected wave returns by applying ultrasonic waves to the sludge interface.

  When measuring the interface position of the sludge by the measuring means 19, when the scraping plate portion 28 in the sludge scraper 24 moves and just enters the measurement point, that is, the ultrasonic wave irradiation point, The measurement value obtained by the ultrasonic wave hitting and reflecting the scraping plate portion 28 is mixed with the sludge measurement data. Thereby, the measurement data of the sludge interface position becomes unclear, the accurate sludge interface position cannot be measured, and the reliability of the measurement data is impaired, so that the ultrasonic wave hits the scraping plate portion 28 and is reflected. Therefore, it is necessary to prevent the measurement values obtained from this from being mixed with sludge measurement data.

  Therefore, when the scraping plate portion 28 in the sludge scraper 24 movably disposed in the sewage treatment tank 12 enters the measurement point of the measurement means 19, the measurement of the measurement means 19 is performed. Means that can be stopped are provided.

  The measurement stop means 21 is a signal that instructs the stop of measurement at the timing when the scraping plate portion 28 of the sludge scraper 24 enters the measurement point of the measurement means 19, that is, the ultrasonic wave irradiation point. Is transmitted to the measuring means 19 and a signal for instructing the resumption of measurement can be transmitted to the measuring means 19 at the timing of leaving the measuring point.

  As the measurement stop means 21, as shown in FIG. 3, the time when the scraping plate portion 28 of the sludge scraping machine 24 approaches the measurement point of the measurement means 19 and the time when it leaves the measurement point. A timer 29 capable of detecting the above is used.

  When it is time for the scraping plate portion 28 of the sludge scraper 24 to approach the measurement point of the measuring means 19, the timer 29 transmits a signal instructing the measuring means 19 to stop measurement. In addition, when it is time for the scraping plate portion 28 of the sludge scraper 24 to move away from the measurement point of the measuring means 19, the timer 29 transmits a signal instructing the measuring means 19 to resume measurement. To do.

Measurement data cannot be obtained while the measurement means 19 is stopped. Therefore, in order to prevent the measurement data from becoming discontinuous, when the measurement is stopped, the measurement unit 19 performs processing so that the measurement data immediately before the measurement stop is held until the measurement is restarted. .
Thereby, as shown in FIG. 4, the continuous measurement data without a blank part can be obtained.

The operation of the above embodiment will be described below.
In the sludge interface measuring apparatus 11 according to the above embodiment, the measuring means 19 measures the interface position of the precipitated sludge section with respect to the supernatant liquid section at a predetermined position in the sewage treatment tank 12. And when the said interface position rises and the said measured value turns into a predetermined value, sludge is discharged | emitted from the said waste-water-treatment tank 12. FIG.
In addition, the said measurement means 19 can measure an interface position by applying the ultrasonic wave irradiated from the ultrasonic transmission part 20 to sludge, and measuring the time until the reflected wave returns.

Since the sludge scraper 16 or the sludge scraper 24 is movably disposed in the sewage treatment tank 12, when the ultrasonic wave is irradiated from the ultrasonic transmitter 20 toward the sludge, the sludge is removed. There is a case where the scraper 16 or the sludge scraper 24 just enters the measurement point. In this case, the ultrasonic wave hits the sludge scraper 16 or the sludge scraper 24 and is reflected, so that the accurate interface position of the sludge cannot be measured.
In order to solve this problem, the sludge interface measuring device 11 stops the measurement of the measuring means when the sludge scraper 16 or the sludge scraper 24 enters the measurement point, and for that purpose. The measurement stop means 21 is provided, and the proximity switch 22 and the timer 29 are used as the measurement stop means 21.

That is, the proximity switch 22 or the timer 29 as the measurement stop means 21 is a signal that instructs the stop at the timing when the sludge scraper 16 or the sludge scraper 24 enters the measurement point of the measurement means 19. Is transmitted to the measuring means 19 and a signal for instructing the restart of measurement is transmitted to the measuring means 19 at the timing of moving away from the measuring point, so that the ultrasonic wave is exactly the sludge scraper 16 or the sludge scraper. When reflected on the machine 24, the measurement data is not obtained.
As a result, the measurement data obtained by the reflection of the ultrasonic wave against the sludge scraper 16 or the sludge scraper 24 is not mixed with the sludge interface position measurement data, and the sludge interface position measurement data is accurate. Reliability is improved.

  When measurement by the measurement unit 19 is stopped by the measurement stop unit 21, a blank portion is generated in the measurement data. To avoid this, the measurement data immediately before the measurement stop is held until the measurement is restarted. . Thereby, the continuity of measurement data is maintained.

  Further, the sludge scraper 16 or the sludge scraper 24 is configured to be able to rotate in the sewage treatment tank 12 or to reciprocate in the sewage treatment tank 12. This can be handled regardless of the shape of the sewage treatment tank 12.

  INDUSTRIAL APPLICABILITY The present invention can be applied to an apparatus for measuring the interface position of sludge in a sewage treatment tank equipped with a sludge scraper or a sludge scraper.

It is a side view of the sludge interface measuring device concerning Example 1. It is a top view of the measurement stop means in the sludge interface measuring device of Example 1. It is a side view of the sludge interface measuring device concerning Example 2. It is a graph figure of the measurement data by an Example. It is a graph figure of the measurement data by a prior art example.

DESCRIPTION OF SYMBOLS 11 Sludge interface measuring device 12 Sewage treatment tank 13 Supernatant discharge part 14 Drainage part 15 Valve 16 Sludge scraper 17 Rotating shaft 18 Blade part 19 Measurement means 20 Ultrasonic transmission part 21 Measurement stop means 22 Proximity switch 23 Detected Member 24 Sludge scraping machine 25 Drive rotation member 26 Driven rotation member 27 Rotation transmission member 28 Scraping plate portion 29 Timer

Claims (6)

Measuring means capable of measuring the interface position of the sedimented sludge portion with respect to the supernatant liquid portion at a predetermined position in the sewage treatment tank, and a sludge scraper or a sludge scraper disposed movably in the sewage treatment tank when entering the measurement point of the measurement means, we have a means capable of stopping the measurement of the measuring means,
The measurement stop means of the measurement means transmits a signal instructing stop at the timing when the sludge scraper or the sludge scraper enters the measurement point of the measurement means, and from the measurement point It is configured to be able to transmit a signal instructing the restart of measurement to the measurement means at the timing of leaving,
As the measurement stop means, a proximity switch that can detect a state where the sludge scraper or a sludge scraper approaches the measurement point of the measurement means and a state where the sludge scraper moves away from the measurement point is used. A sludge interface measuring device characterized by that .   2. The sludge interface measuring apparatus according to claim 1, wherein when the measurement by the measurement stop is stopped by the measurement stop, the measurement data immediately before the stop is held until the measurement is restarted.   The said measurement means is comprised so that interface position can be recognized by measuring the time after a reflected wave returns, after applying an ultrasonic wave etc. to sludge, The structure of Claim 1 or 2 characterized by the above-mentioned. Sludge interface measuring device.   As the measurement stop means, a timer capable of measuring the timing when the sludge scraper or the sludge scraper enters the measurement point of the measurement means and the timing when the sludge scraper moves away from the measurement point is used. The sludge interface measuring device according to claim 1 characterized by.   6. The sludge interface measuring apparatus according to claim 1, wherein the sludge scraper or the sludge scraper is configured to rotate in the sewage treatment tank.   6. The sludge interface measuring apparatus according to claim 1, wherein the sludge scraper or the sludge scraper is configured to reciprocate in the sewage treatment tank.

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