JPH0623210A - Method and device for detecting suspension concentration - Google Patents

Abstract

PURPOSE:To accurately and automatically detect the concentration of a suspension by inserting a pipe into a suspension storing vessel (reaction vessel), precipitating particles in the pipe to turn the suspension into clear water and detecting the difference in water level between the surface of the clear water and that of the suspension in the storing vessel to detect the concentration of the suspension. CONSTITUTION:A pipe 9 is inserted into a reaction vessel 3 and immersed in a suspension. Particles gradually precipitate with the lapse of time from the suspension in the pipe 9 which is turned into clear water. As a result, the difference in specific gravity occurs between the clear water in the pipe 9 and the suspension in the reaction vessel 3 outside the pipe 9, causing the clear water in the pipe 9 to be pushed up by the suspension, permitting the surface of the clear water to be raised higher than that of the suspension in the reaction vessel 3. The difference in water level varies in proportion to the difference in the specific gravity based on the difference in the concentration of the suspension. Therefore, by detecting the difference of water level, the concentration of the suspension is detected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for automatically detecting the concentration of factory wastewater in a water treatment apparatus for treating factory wastewater and the like.

[0002]

2. Description of the Related Art Conventionally, for example,
In a factory that manufactures sanitary ware such as washbasins and a factory that handles glazes such as a tile factory, factory wastewater of a suspension containing glaze is discharged. This factory effluent cannot be discharged as it is to sewage, etc., and must be purified.

FIG. 3 is a system diagram showing an entire apparatus for treating industrial wastewater of a conventional suspension containing glaze. As shown in the figure, in this conventional apparatus, first, factory wastewater of a suspension containing glaze is temporarily stored in a raw water tank 1 and then pumped up by a pump 2 to a reaction tank 3. In the reaction tank 3,
A flocculant such as polyaluminum chloride is added. The coagulant is for promoting coagulation of particles of the suspension in the settling tank 5 described later to improve water treatment efficiency.

By the way, when the coagulant is added, the suspension becomes acidic. Therefore, it is necessary to adjust the pH, and in this conventional apparatus, pH is adjusted by adding NaOH in the next reaction tank 4. Then, finally, the particles of the suspension are settled in the settling tank 5, and only fresh water above is taken out and discharged to sewage or the like.

In order to treat water efficiently, assuming that the inflow rate is constant in the reaction tank 3, an amount of coagulant corresponding to the concentration of the factory wastewater pumped from the raw water tank 1 is used. Need to throw in. However, if the concentration of the factory wastewater is high, the limit amount of the coagulant that can be added to the reaction tank 3 may be exceeded, and normal treatment may not be performed.

Therefore, in the prior art, when a high-concentration factory wastewater in excess of the amount in which the coagulant can be charged flows into the reaction tank 3, the factory wastewater pumped up by the pumping pump 2 is allowed to flow through the relief valve 6. Open operation and return pipe 7 to raw water tank 1
To reduce the amount of factory wastewater flowing into the reaction tank 3 so that a suitable reaction between the flocculant and the suspension can be obtained.

As another conventional method, the raw water tank 1 may be enlarged and averaged so that the influence of the concentration of factory wastewater is reduced. In FIG. 3, 8 is a stirring blade installed in the reaction tank 3.

[0008]

As described above, in the conventional water treatment apparatus, in the case of high-concentration factory wastewater exceeding the amount of coagulant that can be charged in the reaction tank 3, the flow rate of the wastewater should be reduced.
The relief valve 6 is operated to adjust the amount of factory wastewater flowing into the reaction tank 3. However, the flow rate adjustment by the opening / closing operation of the relief valve 6 must be performed while the operator visually confirms the state of the reaction tank 3 based on an empirical rule, and a supervisor must always be arranged. It was also inaccurate and inefficient. Further, in the case of the conventional measures for increasing the size of the raw water tank 1, there are problems such as soaring equipment costs and a large installation space accompanying the increase in size, which is not so common.

As the means for detecting the concentration of the factory wastewater in the reaction tank 3, a transmissive optical sensor such as an infrared sensor is used, and a means for detecting by measuring the amount of transmitted infrared rays or a float is used. There is a means for detecting using a hydrometer, and it is conceivable to control the rotation speed of the pumping pump 2 based on the output signals from these detecting means so as to promote a suitable reaction with the coagulant.

However, when a transmissive optical sensor is used, the particles of the suspension of factory wastewater adhere to the sensor,
It cannot be adopted because it has a drawback that an accurate transmission amount corresponding to the concentration cannot be obtained. Further, even in the method using a hydrometer using a float, particles of the suspension adhere to the float and accurate concentration detection cannot be obtained. Therefore, conventionally, an operator must check the state of the reaction tank 3 based on an empirical rule and control the opening / closing of the relief valve 6 to react the factory wastewater with the coagulant in the reaction tank 3. It was not obtained, and it had the above-mentioned fault.

The pumping pump 2 has a drive switch turned on.
It is always operated with a constant number of revolutions while it is kept at.
Therefore, there is a drawback that the water pressure at the suction port of the pumping pump 2 changes depending on the water level of the raw water tank 1 and the pumping amount changes, so that an appropriate amount of factory wastewater cannot be supplied to the reaction tank 3. . Further, the change in the pumping amount of the pump 2 is also affected by the degree of dust clogging the strainer portion of the pump 2.

[0012]

SUMMARY OF THE INVENTION The present invention has been made by improving the above-mentioned problems in view of the above-mentioned conventional problems, and automatically detects the concentration of a suspension in a reaction tank, and It is an object of the present invention to provide a method and an apparatus capable of controlling the flow rate of a suspension supplied to a reaction tank and automating an entire water treatment system.

Thus, the method adopted by the present invention to solve the above-mentioned problems is to insert a pipe into a suspension storage tank, to settle particles in the pipe into fresh water, and to obtain the fresh water. The suspension concentration detecting method is characterized in that the concentration of the suspension is detected by detecting a water level difference between the water surface and the water surface of the suspension in the storage tank.

In the apparatus adopted by the present invention, the upper end side of the inner pipe provided in the pipe inserted into the suspension storage tank is closed, and the closed chamber is connected to a pressure detector of a diaphragm type or the like. However, a concentration detector for detecting the concentration of the suspension by determining the water level difference between the surface of the fresh water in the pipe and the surface of the suspension in the storage tank from the output signal of the pressure detector is characterized by being provided. This is a suspension concentration detecting device.

[0015]

In the concentration detecting method of the present invention, a pipe is inserted into a storage tank (raw water tank, reaction tank, etc.) and immersed in a suspension. In the suspension in the pipe, particles gradually settle with the passage of time, and the pipe becomes clear water. As a result, a specific gravity difference occurs between the fresh water inside the pipe and the suspension inside the storage tank outside the pipe, and the fresh water inside the pipe is pushed up by the suspension so that its water surface is the suspension inside the storage tank. It will rise above the water level. This difference in water level changes in proportion to the difference in specific gravity based on the difference in concentration of the suspension. Therefore, it is possible to detect the concentration of the suspension by detecting the water level difference.

In the concentration detecting device of the present invention, as means for detecting the water level difference, the upper end side of the inner pipe provided in the pipe inserted into the storage tank is hermetically sealed, and the hermetic chamber is pressure-sensing by a diaphragm type or the like. Connected to the vessel. According to this
Since the water level difference is taken out as a change in pressure, it is possible to detect the water level difference by detecting the pressure in the closed chamber.

[0017]

EXAMPLES The concentration detection method and apparatus of the present invention will be described below.
The following is a description with reference to the drawings on the basis of an example of treating factory wastewater containing a glaze. The same reference numerals as in the conventional case are the same members.

FIG. 1 is a vertical sectional view of a reaction tank 3 for explaining the principle of the concentration detecting method of the present invention. As shown in the figure, in the method of the present invention, the pipe 9 is inserted into the suspension in the reaction tank 3.
Have been inserted. By inserting this pipe 9,
The particles of the suspension in the pipe 9 settle down as time passes, and the pipe 9 becomes clean water. Therefore, a specific gravity difference based on the concentration difference is generated between the pipe 9 and the suspension in the reaction tank 3, and the fresh water in the pipe 9 is pushed up by the suspension to cause a water level difference. Therefore, by detecting this water level difference, it is possible to detect the concentration of the suspension in the reaction tank 3.

For example, a diameter of 100 mm and a length of 100
When a 0 mm pipe is immersed in the reaction tank 3, the specific gravity of water when the water temperature is 20 ° C. is 0.997, and the true specific gravity of the particles of the suspension containing the glaze is 2.65. The relationship among the concentration of the suspension, the specific gravity of the suspension, and the water level difference is as follows. That is, the specific gravity of the suspension when the concentration is 0% is 0.9
97, the water level difference was 0 mm, the suspension specific gravity at a concentration of 0.1% was 0.9976, the water level difference was 0.60 mm, and the suspension specific gravity at a concentration of 0.2% was 0. 9982, the water level difference is 1.20 mm, the suspension specific gravity at a concentration of 0.5% is 1.0001, the water level difference is 3.10 mm, and the suspension specific gravity at a concentration of 1.0%. Is 1.0033
The water level difference is 6.28 mm, the suspension specific gravity at a concentration of 2.0% is 1.0096 and the water level difference is 12.48 mm, and the suspension specific gravity at a concentration of 5.0% is 1 .0291
The water level difference was 31.19 mm.

FIG. 2 is a system diagram showing the whole of the case where the present invention is applied to an apparatus for treating factory wastewater containing glaze based on the principle of detecting the concentration difference. As shown in the figure, in this embodiment, a diameter of 1
A 00 mm pipe 9 is inserted, an inner pipe 11 having a diameter of 75 mm is slidably fitted and mounted on an upper end side of the pipe 9 through a socket 10, and the closed chamber 1 is provided inside the inner pipe 11.
Forming 2. Since the inside of the pipe 9 needs to communicate with the atmosphere, a vent hole (opening port) 17 is required.

Then, the inner pipe 1 forming the closed chamber 12
The upper end side of 1 is communicatively connected to a diaphragm type pressure detector 14 by a hose 13. Further, the pressure detector 14 is connected to a converter 15 for converting its output signal into an electric signal, and its output is inputted to an inverter 16. The inverter 16 frequency-converts the voltage of the converter 15 in accordance with the voltage of the converter 15 to control the pumping pump 2 in the reaction tank 3 by an inverter.

Next, an operation mode of the water treatment system configured as described above will be described. First, a suspension of factory wastewater containing a glaze is temporarily stored in a raw water tank 1 and then pumped to a reaction tank 3 by a pump 2. Thus, in this embodiment, as described later, the frequency of the pump 2 is controlled so that the concentration of the factory effluent can be adjusted to appropriately correspond to the amount of the coagulant such as polyaluminum chloride charged in the reaction tank 3. A flow rate corresponding to the above is drawn from the raw water tank 2 and supplied to the reaction tank 3.

In the reaction tank 3, the water level of the fresh water in the pipe 9 inserted and immersed in the suspension causes a water level difference with the water level of the suspension according to the concentration of the suspension. Become. And, this water level difference is due to the closed chamber 12 on the upper side of the inner pipe 11.
Is detected by the pressure detector 14 as the pressure fluctuation. The output signal of the pressure detector 14 is converted into a voltage signal by the converter 15 and further input to the inverter 16. The inverter 16 frequency-controls the rotation speed of the pumping pump 2 based on the voltage signal value proportional to the output signal of the pressure detector 14.

Therefore, the pumping pump 2 consequently controls the pumping flow rate of the suspension in accordance with the concentration of the suspension in the reaction tank 3 and supplies it to the reaction tank 3. Therefore, even if there is a change in the concentration of the factory effluent flowing into the raw water tank 1, the raw water tank 1 to the reaction tank 3 should be appropriately adjusted to cope with the maximum amount of the coagulant such as polyaluminum chloride that can be added to the reaction tank 3. It is possible to control the amount of waste water supplied to the reactor, and the suspension and the flocculant can be reacted most efficiently in the reaction tank 3. That is, the most efficient water treatment is possible. The water treatment after the reaction tank 3 is the same as the conventional case shown in FIG. 3, and the description thereof is omitted here.

By the way, the present invention is not limited to the above-mentioned embodiments, but can be appropriately modified. For example, the diameter of the pipe 9 may be the same as the stirring blade 8 in the reaction tank 3.
Any size may be used as long as the effect does not affect the inside of the pipe 9 even if the suspension is stirred. Further, the length of the pipe 9 may be appropriately changed depending on the flow rate and the property of the suspension. Further, in the pressure detector 14, when there is air leakage or air is trapped in the drainage, the pump power is turned off every 30 to 60 minutes for about 20 seconds by the timer to lower the water surface. The slide type inner pipe 11 may be opened to the atmosphere and the automatic zero point adjustment may be performed. Furthermore, the water level difference between the fresh water surface in the pipe 9 and the water surface of the suspension liquid can be measured in the inner pipe 11 by using an infrared sensor, an ultrasonic sensor, a float type water level gauge, or the like.

[0026]

As described above, according to the present invention,
The concentration of the suspension is detected by detecting the water level difference between the fresh water in the pipe inserted and immersed in the suspension and the suspension, and the concentration of the suspension can be detected very easily and accurately. It is possible to Further, as a means for detecting the water level difference, the upper end side of the inner pipe is hermetically sealed, and the hermetically sealed chamber is connected to a pressure detector of a diaphragm type or the like so that the water level difference is taken out as a pressure fluctuation in the hermetically sealed chamber and automatically detected. I have to.
Therefore, it is possible to fully automate the water treatment system, and it is not necessary to constantly arrange a monitoring person.

Further, unlike the conventional case, it is not necessary to constantly drive the pumping pump constantly, and the number of rotations of the pumping pump can be controlled according to the concentration, so that the power consumption of the pumping pump can be greatly reduced. It is possible.

Further, in the past, in order to improve the water treatment efficiency, a chemical solution such as a flocculant was added according to the maximum concentration of the suspension, which was wasted when the concentration was low. With, it is possible to appropriately correspond the suspension concentration and the amount of the chemical liquid, and it is possible to reduce the amount of the expensive chemical liquid used.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a reaction tank for explaining the principle of the method of the present invention.

FIG. 2 is an overall system diagram of a water treatment device according to the present invention.

FIG. 3 is an overall system diagram of a conventional water treatment device.

[Explanation of symbols]

 1 ... Raw water tank 2 ... Pumping pump 3 ... Reaction tank 9 ... Pipe 10 ... Socket 11 ... Sliding inner pipe 12 ... Closed chamber 14 ... Pressure detector 15 ... Converter 16 ... Inverter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Norio Nagai 1125-3, Yoshihara, Akechi-cho, Ena-gun, Gifu Prefecture Akechi Inax Co., Ltd.

Claims (2)

[Claims] 1. Inserting a pipe into a suspension reservoir,
It is characterized in that particles in the pipe are settled to form fresh water, and the concentration of the suspension is detected by detecting a water level difference between the surface of the fresh water and the surface of the suspension in the storage tank. Suspension concentration detection method. 2. An output of a pressure detector, wherein an upper end side of an inner pipe provided in a pipe inserted into a suspension storage tank is closed, and the closed chamber is connected to a pressure detector of a diaphragm type or the like for communication. A suspension concentration detecting device provided with a concentration detector for detecting the concentration of the suspension by obtaining a water level difference between the water surface of the fresh water in the pipe and the water surface of the suspension in the storage tank from the signal. .