JPH055456Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a maintenance device for an interface meter (or turbidity meter), and is applicable to batch-type concentration sedimentation tanks or sedimentation ponds that automatically take in supernatant water. used for.

[Conventional technology]

The detector of an interface meter that detects the sludge interface inside a concentration sedimentation tank is always in a liquid containing sludge particles, so sludge particles often adhere to the surface glass of the detector's measurement window. For example, when detecting an interface using an ultrasonic signal, the ultrasonic signal is attenuated by sludge particles adhering to the surface glass, and even if the turbidity of the liquid in the ultrasonic signal propagation path is zero, there is some turbidity. Since the turbidity is detected, the zero point of the turbidity signal shifts, causing an error in the measurement, resulting in the problem that accurate detection is not possible.

In order to solve this problem, conventionally,
No. 75622 and Utility Model Application No. 148661 (1983) are available. This is done by having a pair of detectors constantly follow the interface with a set reference concentration, or by moving them back and forth between a transparent region and a turbid region, and moving the detector to a low concentration position near the water surface or into a transparent region. Sometimes, the zero point is electrically corrected by detecting turbidity at that position.

In addition, as shown in Utility Model Application No. 56-23443, for example, after the detector is lifted up from the measuring liquid and positioned, the solenoid valve for cleaning the detector is opened by a cleaning signal transmitter, and the cleaning water injection nozzle is Physical means are also provided for cleaning the detector by spraying cleaning water.

[Problems that this invention attempts to solve]

However, among the conventional techniques mentioned above, the former means only electrically corrects the zero point of the turbidity signal;
Since the device does not separate and remove the sludge particles attached to the surface glass of the detector, if it is used for a long time, more sludge particles will adhere to and accumulate on the surface glass, and the sludge particles will accumulate at the low concentration position near the water surface as mentioned above. Or, since these sludge particles will be detected when turbidity is detected in the transparent area, there is a risk that turbidity measurement for zero point correction cannot be performed reliably, and the detector must be pulled up and cleaned after all. was necessary.

In addition, the latter physical means requires a cleaning signal transmitter, a solenoid valve for cleaning the detector, an injection nozzle, etc., which makes the device complicated and increases the cost.

This proposal solves the above problem. When the interface meter's detector moves to a clear area that is a set value lower than the supernatant water level, the surface glass of the detector's measurement window is vibrated ultrasonically. To provide a maintenance device for an interface meter, in which sludge particles are removed by washing them into clear water, so that the surface glass is always kept in a clear state, and turbidity can be accurately measured.

[Means for solving problems]

For this reason, the proposed device detects the sludge interface by suspending a pair of detectors in a settling tank with cables and moving them up and down.When the detectors are in supernatant water above, The liquid level detection signal detected by the liquid level gauge and the depth signal detected by the depth sensor are input, and the signal is detected at a depth that is lower than the liquid level by a set value and within a separately set lower limit depth range. a control unit that outputs a rotation signal to the winder to move the detector; and an ultrasonic oscillator that operates according to a start signal output from the control unit.
A vibrator is fixed to the surface glass of the measurement window of the detector and is vibrated by the ultrasonic oscillator, and the vibrator vibrates the surface glass in the supernatant water to remove sludge particles attached to the surface. It is characterized by being separated and removed.

[Effect]

The liquid level detection signal from the liquid level gauge is input to the maintenance circuit section of the control section, and is sent to the winder to move the detector to a position that is a certain value lower than the liquid level set by the reference position setting section. It becomes a rotation signal and is input to the correction circuit. This correction circuit receives a signal of the depth of the detector detected by the depth sensor and determines whether the detector rises above the set value below the liquid level or below a separately set value. When the detector also descends, the rotation signal is corrected by the depth signal and output, and the winder is rotated to feed out or rotate to rewind, thereby lowering or raising the detector. Therefore, in supernatant water where the liquid level fluctuates, the detection unit detects supernatant water within a range whose upper limit is a certain value lower than this liquid level and whose lower limit is a separately set depth. Always follow the clear parts.

A start signal is separately outputted from the correction circuit and input to the ultrasonic transmitter, and when the ultrasonic transmitter is activated by this start signal, a vibrator attached to the surface glass of the measurement window of the detector vibrates. , the sludge particles adhering to its surface are separated. In this case, the detector is placed at a certain depth below the liquid level, which prevents the detector from rising above the liquid level and causing the surface glass to vibrate in the air or near the highly concentrated sludge interface. The sludge particles are washed away into clear water near the liquid surface.

The above maintenance action operates only when the switch in the control unit closes the maintenance circuit side, and when the switch switches to the measurement circuit side after the set time has elapsed,
Normal interface detection is performed.

〔Example〕

The drawing is a conceptual diagram showing one embodiment of the device of the present invention, and this will be specifically explained below.

In the figure, 1 is a batch type concentration sedimentation tank.
The interfacial detector 2 is suspended in the tank by an energized cable 5 extending from the winder 3 through the depth sensor 4. In this example,
Although this detector 2 uses a pair of light emitter 2a such as a light emitting diode and a light receiver 2b such as a phototransistor, it may be a detector using other detection means such as an ultrasonic signal.

In the above detector 2, as schematically shown in FIG. It is connected to the ultrasonic oscillator 12 via a conducting wire 15, a winder 3, and a conducting wire 16.

A liquid level gauge 6 is installed in the settling tank to detect the liquid level w ₁ of the supernatant water w based on the rate of change in capacitance between the atmosphere and water. Other configurations such as those using ultrasonic waves or optical means can be used, and the liquid level detection signal a of the liquid level gauge 6 is transmitted to the maintenance circuit section 7 of the control section 7.
Enter a.

FIG. 2 is a block diagram showing an example of the maintenance circuit section 7a, in which the liquid level detection signal a input to the setting circuit 8 sets the reference position setting section 9 in advance at a position lower than the liquid level by a certain value. By setting, the rotation signal to the winder 3 for moving the detector 2 to a position lower than the liquid level by the set value is inputted to the correction circuit 10.

A signal c of the depth of the detector 2 detected by the depth sensor 4 is input to this correction circuit 10, and the signal c of the depth of the detector 2 detected by the depth sensor 4 is inputted, and the signal c of the depth of the detector 2 is inputted to the correction circuit 10. When it falls below a separately set value, the rotation signal b is corrected by the depth signal c and output, and the winder 3 is rotated to feed out or rotate to rewind, thereby lowering or raising the detector 2. Therefore, in supernatant water where the liquid level w ₁ fluctuates, the detector 2 can measure the temperature within a range where the upper limit is a certain value lower than this liquid level and the lower limit is a separately set depth. It always follows the clear part of the supernatant water.

A starting signal d is separately outputted from the correction circuit 10 and inputted to the ultrasonic oscillator 12 via the sequence control section 11. When the ultrasonic oscillator 12 is activated by this starting signal d, the vibrator 14 is activated.
is subjected to ultrasonic vibration, the surface glass 13 is vibrated, and the sludge particles are separated. In this case, as described above, the detector 2 is placed in a certain depth range below the liquid level, so the detector rises from the liquid level and is exposed to the surface glass 13 in the air or near the high concentration sludge interface. There is no vibration, and sludge particles are reliably washed away in clear water close to the liquid surface.

In the above, the activation signal d may be output when the rotation signal b is not output, that is, when the detector 2 is stationary in clear water, or when the rotation signal b is output, that is, when the detection The output may be output when the device 2 moves within the depth range set as described above. Note that the sequence control unit 11 operates the output activation signal d at a constant cycle, and is not necessarily required.

The above operation operates only when the switch 17 of the control section 7 closes the maintenance circuit section 7a side. This switch 17 is switched by a conventionally known timing circuit containing a timer with a preset time, and after the set time has elapsed, the switch 17 is switched.
is switched to the measurement circuit section 7b side, a rotation signal e is output from the measurement circuit section 7b, the winder 3 is fed out and rotated, the detector 2 is lowered to the interface of the accumulated sludge layer m, and the depth sensor 4 outputs the rotation signal e. The depth signal c and the turbidity signal f detected by the detector 2 are input to the measurement circuit section 7b. After detecting the interface for a predetermined time in this manner, the switch 17 is switched to the maintenance circuit section 7a side, the detector 2 rises into the supernatant water w, and the above operation is repeated.

〔effect〕

As mentioned above, according to the present invention, when the detector is in supernatant water above, the liquid level detection signal detected by the liquid level gauge and the depth signal detected by the depth sensor are input to the control unit, and the output is The winder is driven to move the detector to a depth position lower than the liquid level by a set value and within a separately set lower limit depth range, so the detector always detects the clear portion of supernatant water. In this state, the ultrasonic oscillator is operated to vibrate the vibrator fixed to the surface glass of the measurement window of the detector, and the sludge particles attached to the vibrator are washed away in supernatant water and reliably separated and removed. This has the effect of maintaining good measurement performance and accurately detecting the sludge interface without requiring zero point correction or detector cleaning as in the conventional method.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram of an embodiment of the present device, FIG. 2 is a block diagram showing an example of a maintenance circuit section, and FIG. 3 is a schematic sectional view of one of the detectors. 2...Detector, 3...Winder, 4...Depth sensor, 5...Cable, 6...Liquid level gauge, 7...
...control section, 7a...maintenance circuit section, 7b...measuring circuit section, 12...ultrasonic oscillator, 13...surface glass, 14...vibrator, 17...switch, a...
...Liquid level detection signal, b...Rotation signal, c...Depth signal, w...Supernatant water, _w1 ...Liquid level.

Claims (1)

[Scope of Claim for Utility Model Registration] In a device that detects the sludge interface by suspending a pair of detectors inside a sedimentation tank, etc. with a cable, and moving the detectors up and down, the detectors are placed in the upper supernatant water. At some point, the liquid level detection signal detected by the liquid level gauge and the depth signal detected by the depth sensor are input, and the signal is detected at a depth that is lower than the liquid level by a set value and at a separately set lower limit depth. a control unit that outputs a rotation signal to the winder to move the detector within a range of
a vibrator fixed to the surface glass of the measurement window of the detector and vibrated by the ultrasonic oscillator; the vibrator causes the surface glass to vibrate in the supernatant water, and the sludge particles attached to the surface of the vibrator vibrate in the supernatant water; A maintenance device for an interface meter, characterized in that it separates and removes.