JP3339282B2 - Scale / slime adhesion detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting scale and slime adhesion, and more particularly to a scale and / or scale in an industrial water system such as a paper pulp process white water system or a cooling water system.
Alternatively, the present invention relates to a device for detecting a slime occurrence state.

[0002]

2. Description of the Related Art In various industrial water systems such as a white water system and a cooling water system of a pulp and paper process, scale due to hardness components in water and slime due to microorganisms in water adhere to the system, causing pipe clogging and a decrease in heat exchange efficiency. Cause various adhesion disorders.

Therefore, in these water systems, it is necessary to detect the scale and / or slime adhesion state in the system and take appropriate measures to prevent this adhesion failure. In particular, a scale inhibitor and a slime remover are used to prevent these adhesion failures. In such a case, the scale and slime adhesion in the system must be controlled in order to carry out appropriate chemical injection control. Need to figure out.

Conventionally, there is a monitoring method using a test piece as a method for detecting the adhesion state of scale and slime. In this method, a test piece is placed in a system, taken out after a certain period, and measured for the amount of scale attached and the amount of slime attached.

There is also provided a differential pressure type scale / slime detecting device. This device uses a pipe to detect the scale or slime adhesion state by utilizing a phenomenon in which when a scale or slime adheres to a pipe wall, a differential pressure at a pipe entrance increases.

[0006]

However, in the monitoring method using a test piece, continuous monitoring cannot be performed because the test piece needs to be replaced. Since it is necessary to take out the test piece and measure the amount of scale adhesion and the amount of slime adhesion, it cannot be monitored online. There are drawbacks.

In a water system, there are cases where only slime or scale adheres and cases where they adhere simultaneously. In a differential pressure type scale / slime detector,
There is a disadvantage that it is not possible to distinguish whether the substance adhering to the tube wall is a scale or a slime only from the change in the differential pressure.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a scale and slime adhesion detecting device capable of continuously detecting the amount of scale and / or slime adhesion in a water system online. And

[0009]

According to the scale / slime adhesion detecting device of the present invention, the surface temperature is set to such a value that the scale easily adheres.
A scale adhesion detection unit having a first resistance temperature detector set at a temperature at which microorganisms that cause slime are unlikely to propagate ;
Surface temperature is a source of slime because scale is difficult to adhere
It is characterized by comprising a slime adhesion detection unit having a second resistance temperature detector set at a temperature that does not hinder the growth of microorganisms, and a display unit for displaying the detection results.

During the process using water, scale may adhere to the pipe wall, slime may adhere, or both may adhere simultaneously.

In general, on the surface of a high-temperature object, the saturation concentration of the hardness component in water is reduced, so that the hardness component is easily deposited and the scale is easily attached. On the other hand, the propagation of microorganisms is hindered and the slime does not easily adhere. Conversely, on the surface of a cold object,
Since the saturation concentration of the hardness component in the water increases, the scale does not easily adhere, but the growth of microorganisms is not inhibited and slime adheres easily.

In the present invention, utilizing such a phenomenon ,
It is easy for kale to adhere and microorganisms that are the source of slime
The scale is detected by the first resistance thermometer set at a high temperature, which is difficult to adhere to , and the scale is difficult to adhere and the fine
The slime is detected by the second resistance temperature detector set at a low temperature that does not hinder the propagation of the organism .

A resistance temperature detector used as a sensor in the scale / slime adhesion detecting device of the present invention has a structure in which the electric resistance increases as the temperature rises. , And a structure covered with an insulator such as ceramic.

The resistance temperature detector is, for example, a commercially available product having a length of 1c.
m, the width and the thickness are small pieces of about several mm. Therefore, in the present invention, by using the resistance temperature detector, it is possible to reduce the size of the scale and slime adhesion detection device, and directly to any part of the actual process. It can be installed.

[0015]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the scale / slime adhesion detecting device of the present invention, and FIG. 2 is a system diagram showing a configuration of a temperature measuring section of the scale / slime adhesion detecting device.

As shown in FIG. 1, in the scale / slime adhesion detecting device of the present embodiment, the surface temperature is determined as follows.
The scale adhesion detecting unit 2 having the first resistance temperature detector 1 set at a temperature at which the microorganisms that are the source of the slime are difficult to propagate and the surface temperature is such that the scale does not easily adhere to the slime source
A slime adhesion detection unit 4 having a second resistance temperature detector 3 set at a temperature that does not hinder the propagation of microorganisms to be used, and a display unit for displaying the detection results of the scale adhesion detection unit 2 and the slime adhesion detection unit 4 And 5. In addition, the scale adhesion detection unit 2 and the slime adhesion detection unit 4 are respectively composed of temperature measurement units 2A and 4A and determination units 2B and 4B.
As shown in FIG. 2, the main body of each of the temperature measuring units 2A and 4A includes a constant current generating unit 6 that supplies a constant current to the temperature measuring resistors 1 and 3 so that the temperature measuring resistors 1 and 3 reach a predetermined temperature. A voltage measuring unit 7 for measuring a voltage change due to a temperature rise of the resistance temperature detectors 1 and 3; and a temperature calculating unit 8 for calculating a temperature from the measured voltage.
It is composed of

In the present invention, the resistance temperature detectors 1 and 3 may be of any commercially available shape. For example, at the tip of a hollow plastic case,
A small resistance thermometer with a width of about m, a width and a thickness of several mm is fitted therein, and a lead wire for supplying a current to the resistance thermometer is provided in connection therewith. You can use what you have.

As the determination units 2B and 4B, the temperature measurement unit 2
A computer or the like that determines the slime adhesion status by calculating the detected temperatures of A and 4A by a predetermined calculation formula can be used.

The display section 5 may be any as long as it can display the result of the determination. For example, a monitor television, a liquid crystal panel, a printer, a lamp, a buzzer, or the like can be used.

In order to check the state of adhesion of scale and slime using such a scale / slime adhesion detecting device, as shown in FIG.
The scale / slime adhesion detecting device is installed so that the RTDs 1 and 3 are immersed in the test liquid (service water) at arbitrary locations such as the temperature measuring units 2A and 4A. , 3 are measured, and the determination unit 2 is determined from the measured temperatures.
B and 4B determine the scale and slime adhesion status, respectively.
The result is displayed on the display unit 5.

Specifically, the operation is performed in the following procedure.

[In the case of scale detection] [1] In the initial state (the state where there is no deposit on the surface of the first resistance temperature detector 1), the surface temperature of the first resistance temperature detector 1 The current value of the constant current generator 6 is set so that the temperature of the slime-producing microorganisms is low, for example, 60 to 80 ° C. [2] The voltage between both ends of the resistance bulb 1 is measured by the voltage measurement unit 7. [3] From the voltage measured by the voltage measurement unit 7, the temperature calculation unit 8
Calculates the temperature of the first resistance temperature detector 1 by using
This is sent to the scale adhesion determination unit 2B. [4] The scale adhesion determination unit 2B determines that “scale adhesion is present” when the measured temperature rises above a predetermined threshold value compared to the initial state. [5] Upon receiving the determination result of the scale adhesion determination unit 2B, the display unit 5 displays the determination result.

[In the case of slime detection] [1] In the initial state (the state where there is no deposit on the surface of the second resistance bulb 3), the surface temperature of the second resistance bulb 3 indicates the scale adhesion. The current value of the constant current generator 6 is set so as to be a temperature that does not hinder the propagation of the microorganisms that are the source of the slime, for example, 30 to 37 ° C. [2] The voltage between both ends of the second resistance temperature detector 3 is
Measure with [3] From the voltage measured by the voltage measurement unit 7, the temperature calculation unit 8
Calculates the temperature of the second resistance temperature detector 3 by using
It is sent to the slime adhesion determination unit 4B. [4] The slime adhesion determination unit 4B determines that “slime is present” when the measured temperature rises above a predetermined threshold value compared to the initial state. [5] Upon receiving the determination result of the slime adhesion determination unit 4B, the display unit 5 displays the determination result.

Needless to say, the scale and slime can be detected simultaneously. In addition, the threshold value used as a criterion in the determination units 2B and 4B is determined in consideration of the concentration of the hardness component in the water system, the concentration ratio, the microbial flora forming the slime, the allowable scale, the amount of slime adherence, etc. And can be set arbitrarily.

In the scale / slime adhesion detecting device of the present invention, only a small resistance temperature detector is installed in the test solution. Can be installed in the place.

As shown in FIG. 1, the temperature measuring resistor may be suspended from a water channel or fixed to a wall or the like.

Further, the resistance thermometer may be always installed in the water system and used for continuously monitoring the state of scale and / or slime adherence. It can also be used for evaluation or performance evaluation of slime inhibitors and scale inhibitors.

When the temperature measuring resistor is always installed in the water system, the temperature measuring resistor is washed at an appropriate time. In this case, if the scale and / or slime adherence is detected by the scale / slime adherence detection device of the present invention, if the water system is such that the inside of the system is cleaned with a scale remover or a slime remover, it is supplied. Since the RTD is washed with the scale remover and the slime remover, it is not necessary to separately wash the RTD.

[0030]

The present invention will be described more specifically with reference to the following examples.

Example 1 An experiment for detecting scale and slime was performed using the test apparatus shown in FIG.

An aqueous solution having a hardness of 200 ppm, an M-alkalinity of 200 ppm, and a BOD of 100 ppm was prepared as a test solution, put into a tank 11, extracted with a pump 12 and returned to the tank 11 through a feed pipe 13. . The first resistance temperature detector 14 and the second resistance temperature detector 15 are inserted in the middle of this circulating water system, and the first resistance temperature detector 14
Is set to 70 ° C. and the surface temperature of the second resistance bulb 15 is set to 35 ° C., respectively, and the temperature of the resistance bulbs 14 and 15 is measured by the temperature measuring device 16 having the configuration shown in FIG. did. Further, by measuring the dry weight of the resistance thermometer before and after the scale and slime adhered, respectively, the relationship between the temperature of each resistance thermometer and the amount of the scale and slime adhered was shown in FIG.
It was shown to. In this case, the scale and slime were further distinguished by measuring the acid-dissolved component and the ultrasonic cleaning component.

As shown in FIG. 4, the temperature of the first resistance temperature detector 14 rises as the amount of adhered scale increases, and the temperature of the second resistance temperature detector 15 rises as the amount of adhered slime increases. Thus, it is clear that the scale and slime adhesion detecting device of the present invention can detect the adhesion of scale and slime in an aqueous system to which scale and slime adhere simultaneously.

Example 2 As a test liquid, hardness: 200 ppm, M-alkalinity:
Example 1 except that an aqueous solution of only 200 ppm was used.
A detection experiment was performed in the same manner as described above, and the results are shown in FIG.

As is clear from FIG. 5, the temperature of the first resistance temperature detector 14 rises as the scale adheres, but the temperature of the second resistance temperature detector 15 rises because no slime adheres. I haven't. Therefore, the scale of the present invention
It is clear that the slime adhesion detection device can detect the adhesion of the scale even in an aqueous system to which only the scale adheres.

Example 3 A detection experiment was carried out in the same manner as in Example 1 except that an aqueous solution containing only 100 ppm of BOD was used as a test solution, and the results are shown in FIG.

FIG. 6 shows that the temperature of the first resistance temperature detector 14 has not risen because there is no adhesion of scale. On the other hand, the temperature of the second resistance bulb 15 increases as the slime adheres. Therefore, it is apparent that the scale / slime adhesion detecting device of the present invention can detect the adhesion of slime even in an aqueous system to which only slime adheres.

[0038]

As described in detail above, the scale of the present invention
According to the slime adhesion detection device, a relatively small scale that can be directly installed at any point in the actual process
The slime adhesion detection device can detect the adhesion of scale and / or the adhesion of slime online. The adhesion of the scale and / or the adhesion of the slime can be continuously detected. The adhesion of scale and the adhesion of slime can be individually detected. Thus, it is possible to accurately grasp the scale and / or slime adhesion state of the water system and to surely prevent the adhesion failure.

[Brief description of the drawings]

FIG. 1 is a system diagram showing one embodiment of a scale / slime adhesion detecting device of the present invention.

FIG. 2 is a system diagram showing one embodiment of a temperature measuring unit of the scale / slime adhesion detecting device of the present invention.

FIG. 3 is a system diagram showing a test apparatus used in Example 1.

FIG. 4 is a graph showing the results of a detection experiment of Example 1.

FIG. 5 is a graph showing the results of a detection experiment of Example 2.

FIG. 6 is a graph showing the results of a detection experiment of Example 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st resistance temperature detector 2 Scale adhesion detection part 2A temperature measurement part 2B determination part 3 2nd resistance temperature detector 4 Slime adhesion detection part 4A temperature measurement part 4B determination part 5 display part

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-55-124554 (JP, A) JP-A-2-96644 (JP, A) JP-A-61-26809 (JP, A) JP-A 8- 15189 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01N 25/18

Claims (1)

(57) [Claims] (1) The surface temperature is set so that the scale easily adheres to the surface.
A scale adhesion detecting unit having a first resistance temperature detector set at a temperature at which microorganisms that are the source of the lime are difficult to propagate, and the surface temperature is a source of the slime that the scale is less likely to adhere to.
A scale / slime adhesion detection device comprising: a slime adhesion detection unit having a second resistance temperature detector set at a temperature at which propagation of microorganisms is not hindered; and a display unit for displaying the detection results.