JPH04285821A - Detecting apparatus for foaming - Google Patents

Abstract

PURPOSE:To continuously monitor the presence of bubbles at all tides thereby to improve the detecting accuracy of generation of bubbles and rationalize the defoaming work, by detecting the difference between the position of the upper surface of bubbles when a layer of the bubbles is present and the liquid level in the absence of bubbles. CONSTITUTION:A throw-in type liquid level gauge 4 detects the static pressure of water 3, with outputting a signal 4b. Meanwhile, a sounding liquid level gauge 5 detects shortcircuiting or opening of an electrode 6a and outputs a signal 5a. Since the density of bubbles is smaller than that of tone water 3 even when a layer of bubbles 14 is present over a liquid surface 3a of the water 3, the signal 4b is corresponding to a liquid level L1 of the liquid surface 3a regardless of the presence/absence of the layer 14. If the layer 14 of bubbles is present over the liquid surface 3a, the electrode 6a is shortcircuited at the layer 14. When the layer 14 of bubbles is not present, the electrode becomes shortcircuited at the liquid surface 3a of the water 3. Therefore, the signal 5a is corresponding to a height L2 as tone position of an upper surface 14a of the layer 14. A detecting apparatus 13 which detects generation of bubbles outputs a detecting signal 12a indicating the presence/absence of the generation of bubbles at the liquid surface so that the difference between the signals 5a and 4b becomes a value corresponding to L2-L1.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] The present invention relates to a device for detecting foaming on a liquid surface such as in a discharge channel where treated water is discharged into a river or the like in a treatment plant for sewage or sewage, and in particular, the reliability of foaming detection is The present invention relates to a device that can improve performance.

0002

BACKGROUND OF THE INVENTION In the above-mentioned drainage channels, foams that are difficult to eliminate often occur due to the substances contained in the treated water.
If treated water is discharged with floating foam, it will cause discomfort and a sense of uncleanness to local residents, so conventionally, foaming is visually monitored through a TV monitor, and when foam occurs, the water is discharged upstream of the discharge channel. A defoaming device that extinguishes foam is operated by injecting an antifoaming agent such as clean water or medicine into the discharge channel provided on the side.

0003

[Problems to be Solved by the Invention] Conventionally, foaming has been monitored in the manner described above, making it impossible to continuously monitor the foaming.As a result, foaming is not detected immediately, resulting in foaming. However, even if foaming is detected on a TV monitor, it is not possible to reliably detect when foaming has stopped, which often results in over- or under-injection of antifoaming agent. However, the conventional foam detection device using a television monitor has a problem in that the reliability of foam detection is low and the defoaming operation cannot be carried out rationally.

[0004] An object of the present invention is to improve the reliability of foam detection and streamline defoaming work by making it possible to constantly monitor the presence of foam.

[0005]

[Means for Solving the Problems] In order to achieve the above object, according to the present invention,

1) A first sensor that detects the static pressure of a conductive liquid exposed to the atmosphere and outputs a first signal representing the detection result, and a layer of bubbles formed by bubbles of the liquid on the surface of the liquid. a second sensor that detects the position of the upper surface of the foam layer when the foam layer exists, and detects the liquid level of the liquid when the foam layer does not exist on the liquid surface and outputs a second signal representing the detection result; A foaming detection device is configured to detect foaming at the liquid surface based on the difference between the two signals, and

00
07] 2) In the detection device described in item 1) above, the second
The foam detection device is configured such that the sensor is a capacitive liquid level gauge that detects the position of the upper surface of the foam layer based on the capacitance between the sensor and the foam layer, and

[0008]3
) In the detection device according to item 1), the second sensor is a sounding liquid level gauge that detects the position of the upper surface of the foam layer based on the contact between the electrode and the foam that occurs when at least one electrode is lowered. The foaming detection device is configured as

4) In the detection device described in item 3) above, cleaning means for cleaning the electrode with a clean liquid is provided to constitute a foaming detection device.

0010

[Operation] With the above configuration, even if a layer of bubbles is formed on the liquid surface, the density of this layer of bubbles is very small compared to the density of the liquid, so the first signal represents the liquid level. Therefore, since it is clear that the second signal represents the position of the top surface of the foam layer or the liquid level, the difference between the two signals represents the thickness of the foam layer, and therefore According to the present invention, it is possible to reliably determine when bubbles are generated and when they disappear based on the difference between the two signals, thereby improving the reliability of bubble detection and streamlining the defoaming work.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram of an embodiment of the present invention. In the figure, 1 is a discharge channel with a U-shaped cross section in a sewage treatment plant that is open to the atmosphere 2 and allows treated water 3 to flow in a direction perpendicular to the plane of the figure, and 4 is a discharge channel 1. A pressure sensitive part 4a that detects the static pressure of the water 3 at a predetermined position on the bottom surface 1a of the pipe is fixed in the discharge channel 1, and the pressure sensitive part 4a detects the static pressure of the water 3 at a predetermined position on the bottom surface 1a of the water pipe. 1st signal 4
An immersion type liquid level meter 5 as a first sensor configured to output b, has two electrode rods 6a, 6a fixed at a distance to a single board 6b made of an electrically insulating material as shown in the figure. The detection unit 6 and the detection unit 6 are suspended by a rope 7 as shown in the figure, and the rope 7 is wound and unwound to move the detection unit 6 up and down, and an electrical short circuit between the electrodes 6a, 6a is established. , detects the open state via the cable 8 and connects both electrodes 6.
A second sensor consisting of a main body part 9 which outputs a second signal 5a according to the length of the rope 7 when there is a short circuit between a and 6a, and the aforementioned rope 7 and cable 8. In the sounding liquid level meter, in the liquid level meter 5, when the detection part 6 is lowered by the main body part 9, if the electrodes 6a, 6a are short-circuited, the signal 5a is immediately outputted, and the detection part 6 is pulled up to a predetermined height, and then Thereafter, the main body section 9 is configured to lower the detection section 6 again after a predetermined time τ and hold the value of the signal 5a until a short circuit occurs between the electrodes 6a, 6a again. Reference numeral 10 consists of an electromagnetic valve 10a that opens and closes when a control signal 9a output from the main body 9 is input, and a water injection pipe 10b that discharges clean water 11 such as filtered water in a sewage treatment plant when the valve 10a is opened. By injecting water 11 into the detection part 6 at a predetermined height while it is being lifted up by the main body part 9 through the injection pipe 10b, the substance bridging between the electrodes 6a, 6a is washed away, and the electrical connection between the electrodes 6a, 6a is established. The cleaning means 12, which is set in an open state, calculates the difference D between the value of the signal 5a and the value of the signal 4b, and when this D exceeds a predetermined threshold value S, the signal value becomes "1". A detection signal generating section outputs a detection signal 12a as a binary signal whose signal value becomes "0" when D becomes less than S, and 13 is a detection signal generator that outputs a detection signal 12a as a binary signal whose signal value becomes "0".
This is a foaming detection device including a cleaning means 10 and a signal generating section 12.

In FIG. 1, the sensor 4 is constructed as described above, and even if there is a foam layer 14 made of bubbles of the water 3 on the liquid level 3a of the water 3, the density of the foam layer 14 is lower than that of the water. 3, the signal 4b becomes a signal corresponding to the liquid level L1 of the liquid surface 3a regardless of the presence or absence of the bubble layer 14. Furthermore, in FIG. 1, since the sensor 5 is configured as described above, when a layer of bubbles 14 exists on the liquid surface 3a, the detection part 6 descends and both electrodes 6a and 6a are exposed to the bubble layer. layer 14
Since the foam layer 14 is conductive, a short circuit occurs between the electrodes 6a and 6a, and a foam layer 1 is formed on the liquid surface 3a.
4 is not present, the detection unit 6 descends and the electrodes 6a, 6a
When both contact water 3, a short circuit occurs between the electrodes 6a, 6a, and the signal 5a is transmitted to the upper surface 14a of the foam layer 14.
The height L of the surface 14a from the bottom surface 1a of the waterway as the position of
In FIG. 1, the sensors 4 and 5 and the signal generator 12 are configured so that the above-mentioned signal value difference D becomes a value corresponding to (L2-L1). Therefore, in the foam detection device 13, the detection signal 12a is a signal indicating the presence or absence of foam on the liquid surface 3a, and in the case of this device 13, the presence of the cleaning means 10 ensures that foam detection is performed reliably. This is obvious, and as a result, according to the detection device 13, by shortening the up-and-down movement pause time τ of the detection unit 6 by the sensor main body 9, monitoring of the foaming state can be continued almost constantly using the detection signal 12a. This detection device 13 is said to be a device that can improve the reliability of foam detection and streamline the defoaming work, since it can be used to accurately determine when foam is generated and when it disappears. It turns out.

In the above-described embodiment, the first sensor 4 is an immersion type liquid level gauge and the second sensor 5 is a sounding liquid level gauge, but in the present invention, the sensor 4 is configured by purging fluid such as air or water. A purge type liquid level meter is used to detect the liquid level based on this purge back pressure, and the sensor 5 detects the position of the upper surface 14a of the foam layer based on the capacitance between the sensor 5 and the foam layer 14. In addition, in the present invention, one of the electrode rods 6a, 6a is connected to the bottom surface 1a of the discharge channel.
Another electrode 6a is provided so as to protrude above the bottom surface.
The detection section 6 may be configured by the substrate 6b and the substrate 6b. Further, in the above embodiment, the clean water 11 is intermittently discharged from the water injection pipe 10b, and the detection signal 12a is a binary signal, but in the present invention, the cleaning means is configured to constantly discharge the clean water 11. 10 may be configured, and it is obvious that the signal 12a may be a signal having a value proportional to the signal value difference D. It is then further clear that the present invention is also applicable to foam detection in conductive liquids other than water.

[0014]

[Effects of the Invention] As mentioned above, in the present invention,

[
1) A first sensor that detects the static pressure of a conductive liquid exposed to the atmosphere and outputs a first signal representing the detection result, and a layer of bubbles formed by bubbles of the liquid on the surface of the liquid. a second sensor that detects the position of the upper surface of the foam layer when the foam layer exists, and detects the level of the liquid when the foam layer does not exist on the liquid surface and outputs a second signal representing the detection result. , the foaming detection device is configured to detect foaming at the liquid surface based on the difference between the two signals, and

2) In the detection device described in item 1), the second sensor is a capacitive type that detects the position of the upper surface of the foam layer based on the capacitance between the sensor and the foam layer. The foaming detection device is configured as a liquid level gauge, and

[0017]
3) In the detection device described in item 1) above, the second sensor is used as a sounding level gauge that detects the position of the upper surface of the foam layer based on the contact between the electrode and the foam that is generated by lowering at least one electrode. constitutes a foaming detection device, and

4) In the detection device described in item 3) above, a cleaning means for cleaning the electrode with a clean liquid is provided to constitute a foaming detection device.

Therefore, with the above configuration, even if a layer of bubbles is formed on the liquid surface, the density of this layer of bubbles is very small compared to the density of the liquid, so the first signal is Since it is clear that the second signal represents the position of the top surface of the foam layer or the liquid level, the difference between the two signals represents the thickness of the foam layer. Therefore, according to the present invention, it is possible to reliably determine when bubbles are generated and when they disappear based on the difference between the two signals, thereby improving the reliability of foam detection and streamlining the defoaming work. As a result, the present invention has the effect that the defoaming operation can quickly respond to the foaming state, and effective environmental measures can be taken in sewage treatment plants and the like.

[Brief explanation of the drawing]

[Fig. 1] Configuration diagram of one embodiment of the present invention

[Explanation of symbols]

3 Treated water (conductive liquid) 3a Liquid level 4 First sensor (immersion type liquid level gauge) 4b First signal 5 Second sensor (sounding liquid level gauge) 5a
Second signal 6a Electrode rod (electrode) 10 Cleaning means 11 Clean water 13 Foaming detection device 14 Foam layer L1 Liquid level

Claims (4)

[Claims] 1. A first sensor configured to detect the static pressure of a conductive liquid exposed to the atmosphere and output a first signal representing the detection result, and a layer of bubbles formed by bubbles of the liquid on the surface of the liquid. a second sensor that detects the position of the upper surface of the foam layer when the foam layer exists, and detects the liquid level of the liquid when the foam layer does not exist on the liquid surface and outputs a second signal representing the detection result; A foaming detection device comprising: detecting foaming at the liquid surface based on the difference between the two signals. 2. The detection device according to claim 1, wherein the second
A foam detection device characterized in that the sensor is a capacitive liquid level gauge that detects the position of the upper surface of the foam layer based on the capacitance between the sensor and the foam layer. 3. The detection device according to claim 1, wherein the second
A foam detection device characterized in that the sensor is a sounding liquid level gauge that detects the position of the upper surface of the foam layer based on the contact between the electrode and the foam generated by lowering at least one electrode. 4. The detection device according to claim 3, further comprising a cleaning means for cleaning the electrode with a clean liquid.