JPH0815191A - Suspended substance concentration measuring apparatus - Google Patents

Abstract

PURPOSE:To accurately measure the concentration of suspended substance dispersed in liquid to be inspected real time by converting the measured value of a heat transfer detecting meter to the concentration value of the substance by a converter. CONSTITUTION:A heat transfer detecting meter 1 is dipped in liquid 4 to be detected of an object to be measured, and its sensor 1a is so disposed as to be brought into contact with the liquid 4 to be detected. An agitator 5 is, for example, operated to set the flowing velocity of the liquid 4 to be detected in the sensor 1a of the meter 1 constant. Then, when a voltage value (y) oscillated from the meter 1 is measured, the measured value indicates the solid content (SS) concentration X of the liquid 4 to be detected. The value (y) is input to a converter 2, which calculates X=(y-b)/a (where a, b are constants), and converts the value (y) to an SS concentration value X. The value X is input to a concentration display unit 3, which displays it by a numeric value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a concentration measurement value of suspended matter, and more specifically, it can obtain a concentration measurement value with high accuracy in real time, is easy to handle, and is excellent in cleaning property and durability. The present invention relates to a suspended substance concentration measuring device useful for controlling chemical injection amount in a wastewater treatment device and a sludge dewatering treatment device.

[0002]

2. Description of the Related Art For example, in the dehydration treatment of sludge, in order to improve the dehydration property of the sludge, a centrifugal dehydrator or a coagulation reaction in which a sludge pipe or a dehydrator body is dosed to separate a dehydrated cake and a dehydrated filtrate. For example, a predetermined amount of an organic polymer coagulant is added to the raw sludge supplied to the tank to advance the coagulation reaction, and the coagulated sludge thus prepared is transferred to, for example, a belt press type dehydrator for dehydration. By doing so, an operation of separating the dehydrated cake and the dehydrated filtrate is performed.

In this case, if the amount of the coagulant to be fed to the raw sludge is too small, the coagulation becomes insufficient, and for example, in a belt press type dehydrator, solid-liquid separation by gravity filtration becomes poor, and the coagulated sludge becomes poor. Flow out to the side of the filter cloth, and in the centrifugal dehydrator, the solids recovery rate decreases and the cake water content increases, making it impossible to dehydrate. On the contrary, if the amount of coagulant added is too large, not only the chemicals are wasted, but also the coagulant remains in the coagulated sludge that has been conditioned especially in the belt press dehydrator. As a result, the dehydrated cake adheres to the belt of the dehydrator and the peelability of the dehydrated cake deteriorates. As a result, the recovery rate of the dehydrated cake is reduced.

Therefore, it is necessary to properly control the chemical injection amount of the coagulant into the sludge. In that case, a method has been put into practical use in which the SS (solid content) concentration of the supplied sludge is measured with time, and the coagulant dosage is increased or decreased in proportion to the measured SS concentration. As the SS concentration measuring device used at that time, conventionally, for example, an ultrasonic system, a microwave system, an infrared system, a photoelectric tube system, or the like has been proposed.

However, the ultrasonic method and the microwave method have a problem that the SS concentration cannot be measured with high accuracy. Also, in the case of infrared type or photoelectric tube type, the sensitive part of the device may be contaminated with sludge during the process of using them, which may lower the accuracy of measurement values or cause instability. You will need it. However, in this system, the cleaning performance of the sensitive part is poor, and it is difficult to reuse the cleaning part. That is, these are not preferable in terms of durability during use.

[0006]

DISCLOSURE OF THE INVENTION The present invention is based on the conventional SS.
To solve the above problems in the concentration measuring device, for example,
It is possible to measure the concentration of suspended substances dispersed in test liquids such as various kinds of waste water, treated water, sludge, and dehydrated filtrate of sludge in real time with high accuracy, and also good washability and durability. It is an object of the present invention to provide a suspended substance concentration measuring device having a structure that is easy to handle.

[0007]

In order to achieve the above-mentioned object, in the present invention, a heat transfer detector in which a sensitive part is in contact with a test liquid containing a suspended substance, and the heat transfer detection device A converter that converts the measurement value of the meter into the concentration value of the suspended substance,
There is provided a suspended solid concentration measuring device comprising a concentration indicator for displaying the concentration value.

The measuring device of the present invention will be described in detail below with reference to the drawings. In FIG. 1, a portion A surrounded by a dotted line
Represents a measuring device, which is a heat transfer detector 1 described later,
It is composed of a converter 2 for converting the measured value of the heat transfer detector 1 into a concentration value and a concentration indicator 3 for numerically displaying the concentration value calculated by the converter 2. In this measuring device A, the heat transfer detector 1 is immersed in the test liquid 4 to be measured, and the sensitive portion 1a is arranged so as to come into contact with the test liquid 4 and the measurement operation proceeds.

As the heat transfer detector 1 used, for example,
The hot-wire type flow meter, the hot-film type flow meter, and the thermal conductivity measuring meter which are usually used can be mentioned. Among them, the hot-wire type as disclosed in JP-A-2-290205 Flow meters are preferred. In the case of this heat wire type flow meter, the sensitive portion 1a is formed by a resistance wire having a predetermined resistance value,
For example, a constant current is applied to the resistance wire to heat the resistance wire (sensitive section 1a) to a predetermined temperature.

When the sensitive part 1a is dipped in the test liquid 4 and no change occurs in the test liquid 4, the sensitive part 1
Since a predetermined amount of resistance heat generation in a is depleted by the test liquid 4, the steady state is achieved, so that the voltage drop in the sensitive portion 1a maintains a predetermined value corresponding to the steady state. However, the flow rate of the test liquid 4 changes, or the S of the test liquid 4 changes.
When the S concentration changes and its properties change, the amount of heat taken by the sensitive portion (resistive wire) 1a also changes and the temperature of the sensitive portion 1a changes, which changes the resistance value of the sensitive portion 1a. . Since a constant current is applied to the resistance wire, the measured voltage value changes due to the change in the resistance value.

That is, by measuring the fluctuation of the voltage value, the temperature change of the sensitive portion 1a can be grasped, and the fluctuation of the property of the test liquid 4 can be grasped through the fact. The inventors of the present invention immerse the sensitive part of the hot-wire anemometer in test liquids having different SS concentrations, and measure the voltage fluctuation with the constant flow velocity of the test liquid in the sensitive part.
It was found that the measured voltage value changes in proportion to the SS concentration of the test liquid.

That is, assuming that the SS concentration is x and the voltage value measured by the heat transfer detector is y, the following equation is inserted between y and x: y = ax + b (1) a and b are constants).

Therefore, in the measurement system shown in FIG. 1, for example, the heat transfer detector is operated while the agitator 5 is operated to keep the flow velocity of the test liquid 4 in the sensitive portion 1a of the heat transfer detector 1 constant. If the voltage value (y) transmitted by 1 is measured,
The measured value indicates the SS concentration (x) of the test liquid 4. This measured value (y) is input to the transformer 2, and the transformer 2 performs the calculation represented by the following formula: x = (y−b) / a (2) to calculate the measured value (y) as SS. Convert to the density value (x).

Then, this converted value (x) is obtained by the density indicator 3.
Is input to and displayed numerically there. In addition, in FIG.
The case where the sample liquid 4 is stirred to measure the concentration while the flow velocity in the sensitive portion 1a is in a steady state is shown. For example, the test liquid is flowed in the pipe at a constant flow velocity, and the sensitive portion of the measuring device is arranged there. You may.

Alternatively, the test solution may be kept stationary, and the sensitive part of the measuring device may be immersed therein to measure the SS concentration in the test solution. However, in the case of the heat transfer detector as described above, when the test solution is brought into contact with the sensitive part at a constant flow rate, the value more sensitively corresponds to the SS concentration in the test solution, and the measurement accuracy is improves.

[0016]

The measuring device of the present invention operates based on the principle that the measured value (voltage value) of the heat transfer detector is proportional to the SS concentration of the test liquid. At the time of the measurement, by bringing the test solution into contact with the sensitive section under a constant flow rate condition, it is possible to perform sufficiently accurate measurement even for a small change in SS in the test solution, and the accuracy of the obtained measurement value is high. It is expensive and the measurement work is easy.

Further, since the sensitive portion of the measuring device is formed by the resistance wire, the cleaning at the time of contamination can be easily performed. Therefore, this measuring device can be used for a long time, and its durability is good.

[0018]

Examples of the Invention In the measurement system shown in FIG. 1, as test liquids, diluted urine sludge liquids having different SS concentrations were prepared. The sensitive part 1a of the heat transfer detector 1 is immersed in 2 liters of each sludge diluent 4 and the stirrer 5 is set to 100 rp.
Rotate at m to form a steady-state agitated flow, and
The voltage value was measured in a state where the energization amount to a was set to a constant value of 500 mA.

The measured values at that time are shown in FIG. 2 as a relational diagram with the SS concentration of the sludge dilution liquid. As is clear from FIG. 2, the measured value obtained from the heat transfer detector has a linear relationship with the SS concentration. That is, this relationship is stored in the converter 2, and the voltage value of the sludge whose SS concentration is unknown is measured by a heat transfer detector. In the transformer 2, the value is calculated from the relationship shown in FIG. It can be converted into a value. The converted value is displayed numerically on the density display 3.

[0020]

As is apparent from the above description, the measuring apparatus of the present invention can quantify the SS concentration of the test liquid in real time with a very simple operation. Further, the sensitive part has good cleaning properties, and therefore has a long service life and excellent durability. This is an effect brought by incorporating a heat transfer detector showing a linear relationship between the SS concentration and the measured value.

The measuring device of the present invention is useful for controlling the amount of chemical injection in a wastewater treatment device, a sludge dewatering device and the like.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a measuring device of the present invention.

FIG. 2 is a graph showing a relationship between a measured value of a heat transfer detector and SS concentration.

[Explanation of symbols]

 1 Heat Transfer Detector 1a Sensitive Section of Heat Transfer Detector 1 2 Converter 3 Concentration Value Display 4 Test Liquid 5 Stirrer

Claims (1)

[Claims] 1. A heat transfer detector whose sensitive part is in contact with a test liquid containing a suspended substance, and a converter for converting a measured value of the heat transfer detector into a concentration value of the suspended substance, A suspended solid concentration measuring device comprising a concentration indicator for displaying the concentration value.