JPH11125596A - Optical liquid measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an optical liquid measuring device for widening the control region and stabilizing the control of a processing system by reflecting light transmitted through a liquid to be measured, by detecting the reflected light with a photo sensor, and similarly making the slant of the correlation between the state of the liquid to be measured with the nearly proper amount of chemical the same as the slant of the correlation before and after it. SOLUTION: When a liquid 11 to be measured is nearly transparent, one part of light being applied from a photo sensor 1 transmits a light transmission water channel 2 and the liquid 11 to be measured, is reflected by a reflector 3, furthermore, transmits the light transmission water channel 2 and the liquid 11 to be measured, and is received by the photo sensor 1. As a result, the correlation between the state of the liquid to be measured and a reflection factor differs from that when there is no reflection plate 3 and indicates the similar slant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical liquid measuring apparatus suitable for measuring the state of a liquid such as a sludge dewatering separation liquid or treated water by the reflectance of light.

[0002]

2. Description of the Related Art The state of a sludge dewatering separation liquid when a coagulant is injected into a sludge to be treated in a sludge treatment system comprising a centrifugal dehydrator and a coagulant injection device, and the state of treated water in a wastewater treatment system are monitored. For this reason, chromaticity meters and turbidity meters are used. Data detected by these instruments is often used for controlling the operation of a centrifugal dehydrator or a coagulant injection device.

FIG. 5 is a block diagram showing a conventional optical liquid measuring device. In FIG. 5, reference numeral 1 denotes an irradiation unit (not shown) such as a light emitting diode and a light receiving unit (not shown) such as a photodiode. An optical sensor that irradiates the liquid to be measured 11 (for example, sludge dewatering separation liquid or treated water) in the water tank 21 with light at the irradiation unit, and receives the light reflected by the liquid to be measured 11 at the light receiving unit. Yes, 21 is the liquid 1 to be measured
This is a water tank that holds 1.

Next, the operation will be described. The light to be measured 11 is irradiated with light by the optical sensor 1. Part of the light is reflected by the liquid to be measured 11 and enters the optical sensor 1. Then, the optical sensor 1 receives the reflected light and outputs the intensity of the reflected light as an electric signal. The data detected in this way is used for controlling the injection amount of chemicals in a sludge dewatering machine, for example.

FIG. 6 shows the relationship between the state of the liquid to be measured 11 and the reflectance detected by the optical sensor 1 when the liquid to be measured 11 is a sludge dewatering / separating liquid. The reflectance is an amount obtained by dividing the intensity of the reflected light by the intensity of the irradiation light.

When the centrifugal dewatering of the sludge is performed, the state of the liquid 11 to be measured can be roughly divided into three according to the sludge properties and the amount of the mixed chemical (aggregating agent). If the amount of chemicals is excessive, white foam is generated in the liquid, and if the amount of chemicals is almost appropriate, the liquid becomes almost transparent and the sludge properties are poor or if the amount of chemicals is insufficient, the liquid Black sludge particles are formed on the surface. Examples of the reflectances detected in these three cases are shown below. Case 1: Liquid with bubbles (white) on the surface Reflectivity = about 90
% To about 100% Case 2: Liquid without bubbles or sludge particles Reflectivity = about 5
% To about 25% Case 3: Liquid with sludge particles (black) Reflectivity = about 15
% To about 30%

[0007] When the amount of the chemical is excessive, the number of bubbles increases as the amount of the chemical increases, and the reflection of light by the bubbles increases, so that the reflectance also increases. When the amount of the chemical is almost appropriate, the transparency of the liquid increases as the amount of the chemical increases, and the transmittance and dispersion of light increase, so that the reflectance decreases. When the amount of chemical is insufficient, the amount of sludge particles (black) increases as the amount of chemical decreases, so that the light absorption rate increases and the reflectance decreases. However, in this case, since there is reflection on the sludge particle surface, the reflectance tends to increase as compared with the case where the amount of the chemical is almost an appropriate amount.

That is, when the amount of the chemical is excessive, bubbles are generated. Therefore, there is a substantially positive correlation between the state of the liquid to be measured and the reflectance. There is a negative correlation between the state of the measurement liquid and the reflectance, and when the amount of the chemical is insufficient, the sludge particles are contained,
There is a positive correlation between the state of the liquid to be measured and the reflectance. Therefore, in the case where the detected reflectance is used for controlling the injection amount of the medicine, the vicinity of the state where the amount of the medicine is appropriate,
Only the region where the slope of the correlation is constant is set as the control region.

The relationship between the reflectance and the state of the liquid to be measured is, for example, as shown in FIG.
It changes according to sludge 2). In this case, when the amount of the chemical is almost appropriate, the reflectance of the sludge 1 is about 5% to about 2%.
Although in the range of 0%, the reflectance of the sludge 2 is relatively unchanged. In FIG. 6, the reflectance characteristics when the liquid contains bubbles or sludge particles are shown linearly. However, in actuality, the amount of bubbles or the amount of In many cases, the reflectance differs depending on the positional relationship between the optical sensor 1 and the optical sensor 1, and the detected reflectance varies.

[0010]

Since the conventional optical liquid measuring apparatus is constructed as described above, when controlling the processing system in accordance with the value of the reflectance, the amount of the chemical is almost appropriate. The slope of the correlation between the state of the liquid to be measured and the reflectance (= negative) and the slope of the correlation between the state of the liquid to be measured and the reflectance when the amount of the chemical is excessive or insufficient (= positive)
Therefore, the same reflectance may be exhibited even when the state of the liquid to be measured is different (see FIG. 6). for that reason,
When using reflectance for operation control, it is necessary to set a control area (controllable section) only when the amount of chemicals is almost appropriate, and to control the processing system when bubbles or sludge particles are contained. There is a problem that it is difficult to perform the processing and the processing system may be unstable. further,
Since the reflectance tends to vary depending on the distance between the liquid 11 to be measured and the optical sensor 1 and the state of the liquid to be measured, it is difficult to perform stable processing for a long time even if the set value for operation control is determined. There was a problem that was.

A sensor for detecting the generation of bubbles and a sensor for detecting the mixing of sludge particles are provided, and the control mode is switched in accordance with the above three cases. Can be performed to expand the control area, but in that case, the size of the entire device is increased, and the cost of the device is also increased. Further, a mechanism for removing bubbles or sludge particles from a portion irradiated with light by the optical sensor 1 can be added to the water tank 21, but in that case, the cost of the apparatus also increases. In some cases, a plurality of optical sensors must be used.

Further, when the properties of the sludge and the type of the flocculant are changed, the reflectance when the amount of the chemical is appropriate is changed in accordance with the properties of the sludge and the type of the flocculant. Since it is narrow, it is necessary to frequently adjust the optical sensor and the like so that the reflectance when the amount of the medicine is appropriate is set at almost the center of the control area, and there are also problems such as the troublesome adjustment of the device. there were.

The present invention has been made in order to solve the above-mentioned problems. For example, the light transmitted through the liquid to be measured 11 is reflected by a reflector, and the reflected light is detected by the optical sensor 1. By making the slope of the correlation between the state of the liquid to be measured and the reflectivity when the amount of the chemical is almost the same as the slope of the correlation before and after, the control area is widened and the control of the processing system is stabilized. An object of the present invention is to obtain a liquid measuring device.

Further, the present invention has been made to solve the above-mentioned problems. For example, a reflection plate is disposed so as to face an optical sensor to reflect light transmitted through a liquid to be measured, and the optical sensor is used to reflect the light. It is an object of the present invention to obtain an optical liquid measuring device that detects a change in reflectance depending on the properties of sludge and the type of a coagulant, thereby simplifying adjustment of the device.

[0015]

An optical liquid measuring apparatus according to the present invention irradiates light and receives an incident light. An optical sensor is provided to face the optical sensor. Provided with a reflecting plate for reflecting the reflected light, and a liquid holding means provided between the optical sensor and the reflecting plate and having at least a light transmitting portion for transmitting the light from the optical sensor and the reflecting plate. It is.

In the optical liquid measuring apparatus according to the present invention, the first adjusting means for adjusting the distance between the optical sensor and the liquid holding means and / or the second adjusting means for adjusting the distance between the reflecting plate and the liquid holding means. Means.

The optical liquid measuring device according to the present invention has, as the liquid holding means, any one of a water pipe through which the liquid passes, a water path through which the liquid passes, and a water tank through which the liquid stays.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 shows an optical liquid measuring apparatus according to a first embodiment of the present invention. In the figure, reference numeral 1 denotes an irradiating section (not shown) such as a light emitting diode and a light receiving section (not shown) such as a photodiode. The irradiating section irradiates the liquid to be measured 11 in the light transmission channel 2 with light, and the light reflected by the liquid to be measured 11 at the light receiving section and transmitted through the liquid to be measured 11 from the reflecting plate 3. An optical sensor for receiving light, 2 is a light transmitting water channel (liquid holding means) formed of a light transmitting member and serving as a flow path of the liquid 11 to be measured, 3 is arranged opposite to the optical sensor 1, A reflecting plate 31 reflects the light transmitted through the light transmission channel 2 and the liquid to be measured 11 toward the optical sensor 1. Reference numeral 31 moves the optical sensor 1 perpendicularly to the light transmission channel 2. Actuator for adjusting the distance between the light transmission channel 2 and Numeral 32 denotes an actuator (second adjusting means) for moving the reflecting plate 3 perpendicular to the light transmitting channel 2 and adjusting the distance between the light transmitting channel 2 and the reflecting plate 3. .

Next, the operation will be described. The optical sensor 1 irradiates the liquid to be measured 11 with light through the light transmission channel 2. A part of the light is reflected by the liquid to be measured 11 and is incident on the optical sensor 1, and the other part is transmitted through the light transmission channel 2 and the liquid to be measured 11 and is incident on the reflecting plate 3. Light incident on the reflector 3 is reflected by the reflector 3 toward the optical sensor 1. Then, a part of the reflected light passes through the light transmission channel 2 and the liquid to be measured 11 again, and enters the optical sensor 1. The optical sensor 1 receives the light reflected by the liquid to be measured 11 and the light reflected by the reflector 3,
The intensity of the reflected light is output as an electric signal. This electric signal is used, for example, for controlling the above-described processing system.

FIG. 2 shows the state of the measured liquid 11 and the first embodiment when the measured liquid 11 is a sludge dewatering / separating liquid.
2 shows an example of a relationship with the reflectance detected by the optical sensor 1 of FIG.

When bubbles are generated in the liquid 11 to be measured,
The light emitted from the optical sensor 1 is almost reflected by the bubbles, and hardly passes through the liquid 11 to be measured. When the liquid 11 to be measured contains sludge particles, the light emitted from the optical sensor 1 is absorbed by the sludge particles. Almost no transmission. Therefore, when bubbles or sludge particles are included, there is almost no effect on the reflectivity of the reflecting plate 3, and the relationship between the state of the liquid to be measured and the reflectivity in this case is determined by the apparatus shown in FIG. (FIG. 6).

On the other hand, when the amount of the chemical is substantially appropriate and the liquid is substantially transparent, the transparency of the liquid increases as the amount of the chemical increases, and the proportion of light transmitted through the liquid 11 to be measured increases. Therefore, the light is reflected by the reflection plate 3 and
Is increased as the amount of chemicals increases, so that the detected reflectance increases. Therefore, in this case, the slope of the correlation between the state of the liquid to be measured and the reflectance is positive. As described above, since the slope of the correlation between the state of the liquid to be measured and the reflectance when the amount of the chemical is substantially appropriate is positive, the correlation between the state of the liquid to be measured and the reflectance in the above three cases is positive. The slopes all have the same sign (= positive).

The optical sensor 1 and the reflecting plate 3 are provided so that the distance between the optical sensor 1 and the light transmitting channel 2 can be adjusted by actuators 31 and 32. By adjusting the distance between the light sensor 1 and the reflection plate 3 and the light transmission channel 2, it is possible to adjust the magnitude of the reflectance to be detected. As an example in the case where the reflectance is used for control, as shown below, the reflectance when the liquid 11 to be measured is in a transparent and good state is about 50%, and the reflectance when bubbles are generated is reduced. The reflectance is adjusted so as to be about 90% or more and the reflectance when sludge particles are included is about 30% or less. Case 1: Liquid with bubbles (white) on the surface Reflectivity = about 90
% To about 100% Case 2: Liquid without bubbles or sludge particles Reflectivity = about 40
% To about 60% Case 3: Liquid with sludge particles (black) Reflectivity = about 15
% To about 30%

Also, depending on the installation location of the device, the optical sensor 1
However, by adjusting the distance between the light sensor 1 and the reflection plate 3 and the light transmission channel 2 using the actuators 31 and 32, an optimum response can be obtained at that location. .

As described above, according to the first embodiment, the inclination of the correlation between the state of the liquid to be measured and the reflectance is made positive by using the reflecting plate 3, whereby the above-mentioned three cases can be obtained. By setting the slope of the correlation between the state of the liquid to be measured and the reflectance to have the same sign (= positive), the control area can be widened and the control of the processing system can be stabilized.

Further, since the light transmitted through the liquid 11 to be measured is detected by using the reflection plate 3, the influence of the light dispersion on the detected reflectance is reduced, and the properties of the sludge and the flocculant are reduced. In this case, it is possible to suppress the fluctuation of the reflectance depending on the type of the device, and to simplify the adjustment of the device.

In the first embodiment, an example in which the present invention is used for a sludge dewatering machine is shown as an example. However, the present invention also relates to a water quality property in each process of a water treatment facility such as monitoring of treated water. It can also be used for monitoring and controlling.

In the first embodiment, the position of both the optical sensor 1 and the reflecting plate 3 can be adjusted. However, one of the optical sensor 1 and the reflecting plate 3 can be adjusted. It may be fixed so that only the other position can be adjusted. In that case, since only one actuator is required, the cost of the apparatus can be reduced.
In addition, the adjusting means is not limited to the actuator,
What is necessary is just to be able to finely adjust the positions of the optical sensor 1 and the reflecting plate 3.

Further, a color (chromaticity) sensor using infrared light is generally used as the optical sensor 1, but a sensor using visible light or ultraviolet light may be used.

Embodiment 2 FIG. FIG. 3 shows an optical liquid measuring apparatus according to Embodiment 2 of the present invention. Embodiment 2
In this embodiment, instead of the light transmitting water channel 2 of the first embodiment, an open water channel (liquid holding means) 4 which is surrounded on three sides by a light transmitting member and whose upper side is opened is provided. The operation of detecting the reflectance in the second embodiment is the same as the operation of the first embodiment, and thus the description is omitted. The optical sensor 1 and the reflection plate 3 may be provided on the side of the open channel 4. As described above, according to the second embodiment, the same effect as in the first embodiment can be obtained even when the open channel 4 is used as the flow path of the liquid 11 to be measured.

Embodiment 3 FIG. 4 shows an optical liquid measuring apparatus according to Embodiment 3 of the present invention. Embodiment 3
In this embodiment, a water tank (liquid holding means) 5 having a lid 5a and a bottom 5b formed of a light transmitting member is provided instead of the light transmitting water channel 2 of the first embodiment. However, the installation of the lid 5a is optional, and the upper part of the water tank may be open. Further, the optical sensor 1 and the reflection plate 3 may be arranged on the side surface (for example, 5c and 5d) of the water tank 5. The operation of detecting the reflectance in the third embodiment is the same as that in the first embodiment.
Since the operation is the same as that described above, the description thereof is omitted. As described above, according to the third embodiment, the same effects as in the first embodiment can be obtained even when the water tank 5 is used as the flow path of the liquid 11 to be measured.

[0032]

As described above, according to the optical liquid measuring apparatus of the present invention, an optical sensor that irradiates light and receives incident light, and is provided to face the optical sensor, A reflecting plate that reflects the irradiated light; and a liquid holding unit that is provided between the optical sensor and the reflecting plate and has at least a part that has a light transmitting unit that transmits light from the optical sensor and the reflecting plate. Therefore, the slope of the correlation between the state of the liquid to be measured and the reflectance detected by the optical sensor is positive, and the control area can be set wider, and the control of the processing system can be stabilized. There is.

According to the present invention, the light transmitted through the liquid is detected using the reflection plate, so that the influence of the light dispersion on the detected reflectance is reduced, and the properties of the sludge and the flocculant are reduced. There is an effect that the fluctuation of the reflectance according to the type of the light source can be suppressed and the adjustment of the device can be simplified.

According to the present invention, the first adjusting means for adjusting the distance between the optical sensor and the liquid holding means and / or the second adjusting means for adjusting the distance between the reflecting plate and the liquid holding means are provided. There is an effect that an optimum response can be obtained according to the state of the liquid to be measured and the installation location of the device.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an optical liquid measuring device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a state of a liquid to be measured and a reflectance detected by an optical sensor according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing an optical liquid measuring device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing an optical liquid measuring device according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional optical liquid measuring device.

FIG. 6 is a diagram showing a relationship between a state of a liquid to be measured and a reflectance detected by an optical sensor by a conventional optical liquid measuring device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Optical sensor 2 Liquid holding means (light transmission channel) 3 Reflector 4 Liquid holding means (open channel) 5 Liquid holding means (water tank) 11 Liquid to be measured 31 First adjusting means (actuator) 32 Second adjusting means ( Actuator)

Claims (3)

[Claims] An optical sensor for irradiating light and receiving incident light; a reflecting plate provided to face the optical sensor and reflecting light emitted from the optical sensor; An optical liquid measurement device provided between the reflection plate and a liquid holding unit having at least a part of the optical sensor and a light transmission unit that transmits light from the reflection plate. 2. The apparatus according to claim 1, further comprising first adjusting means for adjusting the distance between the optical sensor and the liquid holding means and / or second adjusting means for adjusting the distance between the reflecting plate and the liquid holding means. The optical liquid measuring device according to claim 1, wherein: 3. The optical device according to claim 1, wherein the liquid holding means is any one of a water pipe through which the liquid passes, a water passage through which the liquid passes, and a water tank through which the liquid stays. Liquid measuring device.