JPH11153557A - Slime or scale adhesion detector - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a slime or scale adhesion detecting device capable of detecting slime adhesion amount with high accuracy. SOLUTION: A slime including a temperature measurement unit 2 using a resistance temperature detector 1 in contact with a test liquid, a determination unit 3 for determining a slime generation state from a measured temperature, and a display unit 4 for outputting a determination result. Alternatively, in the scale adhesion detecting device, a temperature measuring resistor 1 having a non-smooth surface in contact with the test liquid is used.

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 slime or scale adhesion, and more particularly to an apparatus for detecting slime or scale generation in industrial water, for example, a white water system or a cooling water system for a paper pulp process.

[0002]

2. Description of the Related Art Paper pulp process In various industrial water systems such as white water system and cooling water system, slime generated by the action of organic nutrients and turbidity and microorganisms in the system, or hardness components in water, etc. The scale generated by the concentration causes various slime or scale adhesion failures such as clogging of pipes, reduction of heat exchange efficiency, and paper breakage in a paper making process.

Accordingly, in these water systems, it is necessary to detect the slime or scale adhesion state in the system and take appropriate measures to prevent slime or scale adhesion failure. In particular, a slime inhibitor, a slime remover, or a scale inhibitor is used to prevent slime or scale adhesion failure. Alternatively, it is necessary to grasp the state of scale adhesion.

Conventionally, there is a monitoring method using a test piece as a method for detecting the state of adhesion of scale and slime. In this method, a test piece such as a rubber plate is immersed in a system, taken out after a certain period of time, and measured for the amount of scale attached and the amount of slime attached. However, this method relies on manual labor, and the operation is complicated.
The measurement accuracy is poor, the measurement takes a long time, and the adhesion state cannot be grasped immediately.

[0005] A differential pressure type slime or scale adhesion detecting device is also provided. This device uses piping,
The slime or scale adhesion state is detected by utilizing the phenomenon that the differential pressure between the pipe entrance and the outlet increases when slime or scale adheres to the pipe wall.

However, this differential pressure type detection device is large in size and requires a large installation area. Cannot be installed during the actual process. For this reason, it is necessary to provide a bypass pipe for detection. However, it is difficult to match the condition of the bypass system with the condition of the actual process, so that the detection accuracy is not sufficient. There are drawbacks.

[0007] As a small slime detecting device which can solve such a problem and can be installed at an arbitrary position in an actual process, the present applicant has previously provided a measuring device provided so that the surface is in contact with the test liquid. A temperature measuring element, comprising: a temperature measuring element; an energizing means capable of energizing the temperature measuring element; and a control means capable of controlling an amount of energizing current from the energizing means. Means for intermittently supplying a constant current of a predetermined value or more to the resistance bulb to raise the temperature of the resistance bulb,
A slime detection device comprising means for detecting the applied voltage during energization has been developed, and a patent application has been filed (Japanese Patent Application No. 9-1 / 1991).
No. 47767. Hereinafter, it is referred to as “first application”. ).

In the slime detection device of the prior application, a current is not supplied to the resistance temperature detector at all times, or a constant current is supplied so that the temperature of the resistance temperature detector becomes 30 to 37 ° C. (for example, 35 ° C.). Keep it. Then, a relatively large constant current is applied to the temperature measuring resistor for a predetermined period of time (for example, at a rate of one minute per hour). The amount of current supplied at this time is selected so that the temperature of the resistance bulb becomes, for example, 40 to 100 ° C. Then, the applied voltage at the time of the energization is detected, and based on the voltage (or based on the temperature of the resistance temperature detector obtained in correspondence with this voltage), the state of slime adhesion to the resistance temperature detector is detected.

In the prior application, the temperature measuring resistor is intermittently heated to a relatively high temperature. Generally, when the temperature of the resistance temperature detector is raised to a high temperature, slime adherence to its surface is inhibited. However, in the prior application, raising the temperature to this high temperature is a very short time (for example, about one minute per hour), so that there is no problem in the slime adhesion behavior to the resistance temperature detector and does not hinder slime detection. .

[0010] The resistance thermometer used as a sensor in the slime detection device of the prior application has an electric resistance that increases as the temperature rises. In the prior application, the following A is a specific example of the resistance thermometer. , B are exemplified.

A: A structure in which a platinum wire in a coil shape is covered with an insulator such as ceramic. For example, a small resistance thermometer having a length of about 1 cm, a width and a thickness of several mm is fitted into the tip of a hollow plastic case, and a conductor for supplying a current to the resistance thermometer is connected and provided. Is drawn out from the other end of the plastic case. B: A platinum pattern is formed on one or both plate surfaces of an insulating substrate such as a ceramic, for example, in a zigzag pattern, and a coating layer of glass or the like is formed so as to cover the platinum pattern (this coating layer is a platinum pattern Formed to prevent cutting or peeling.

The resistance temperature detector is a small piece having a length of about 1 cm, a width and a thickness of several mm, for example. Therefore, the slime detection device of the prior application can be miniaturized, and can be directly applied to an arbitrary part of an actual process. Can be installed.

[0013]

According to the slime detection device of the prior application, a small slime detection device which can be directly installed at an arbitrary position in an actual process is provided. At present, there is a demand for the development of a detection device with higher measurement accuracy in order to accurately grasp the slime or scale from the initial stage and to more reliably prevent the adhesion failure of the slime or scale.

The present invention has been made in view of such circumstances, and is a small slime or scale adhesion detecting device which can be directly installed at an arbitrary position in an actual process, and has high measurement accuracy and high slime. It is another object of the present invention to provide a slime or scale adhesion detecting device capable of accurately grasping the occurrence of scale from an initial stage.

[0015]

According to the present invention, there is provided a slime or scale adhesion detecting device comprising: a temperature measuring resistor provided so that a surface thereof is in contact with a test liquid; A slime or scale adhesion detection device comprising: a control means capable of controlling an amount of current supplied from the current supply means, wherein a surface of the temperature measuring resistor which comes into contact with the test liquid is a non-smooth surface. It is characterized by being.

The measuring principle of the slime or scale adhesion detecting device according to the present invention is exactly the same as that of the detecting device of the prior application, but in the present invention, the temperature measuring resistor has a non-smooth surface in contact with the test liquid. Since a surface is used, slime or scale easily adheres to the surface of the RTD.

For example, a glass plate having a smooth surface (surface roughness R
a = 0.1 μm) and a ground glass plate having a non-smooth surface (surface roughness Ra = 2 μm) are immersed in a circulating water tank of a cooling tower under the same conditions for 3 days, and the slime adhesion amount is as follows. It is clear that slime is more likely to adhere to a ground glass plate having a non-smooth surface than to a glass plate having a smooth surface.

In the case of a glass plate having a smooth surface: 3 mg / dm ^{2 In} the case of a ground glass plate having a non-smooth surface: 8 mg / dm ² Therefore, in the slime or scale adhesion detecting device of the present invention, the amount of slime or scale on the surface of the resistance temperature detector is measured. Since the adhesion is promoted, the generation of slime or scale can be detected from an early stage, and the measurement error can be suppressed to a small value to increase the measurement accuracy.

[0019]

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 a slime or scale adhesion detecting device of the present invention, FIG. 2 is a system diagram showing a configuration of a temperature measuring section of the slime or scale adhesion detecting device, and FIG. It is explanatory drawing which shows embodiment of the temperature measuring resistor which concerns on this invention, (a) figure is a top view, (b) figure is sectional drawing in alignment with the BB line of (a) figure.

As shown in FIG. 1, the slime or scale adhesion detecting device of the present embodiment comprises a temperature measuring section 2 having a resistance temperature detector 1, a judging section 3 and a display section 4.

The main body of the temperature measuring section 2 is as shown in FIG.
A constant current generating unit 5 for supplying a current to the resistance thermometer 1 via a conduction control unit 8; a voltage measuring unit 6 for measuring a voltage when a constant current is supplied to the resistance thermometer 1; And a temperature calculation unit 7 for calculating.

As the determination unit 3, a computer or the like that determines the state of slime adhesion by calculating the temperature detected by the temperature measurement unit 2 using a predetermined formula can be used.

The display section 4 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.

As shown in FIG. 3, the RTD 1 is formed by forming a platinum pattern 12 in a zigzag pattern on the surface of an insulating substrate 11 made of ceramic or the like, and covering the surface on which the platinum pattern 12 is formed with glass or plastic. The surface of the coating layer 13 is formed as a non-smooth uneven surface. 14A and 14B are lead wires.

The irregularities on the surface of the coating layer can be formed by, for example, a physical method of spraying an abrasive such as sand on the surface of the coating layer (sandblasting), or a chemical method of etching with a chemical. In the case of a glass coating layer, ground glass may be used.

The surface irregularities of the resistance temperature detector 1 are preferably formed uniformly over the entire surface, and the degree of the irregularities is 1 μm or more in surface roughness Ra, especially 2-3 μm.
m is preferable.

In the present invention, the structure of the resistance thermometer is not only a structure in which a platinum pattern is formed on an insulating substrate and covered with a coating layer, but also a structure in which a platinum wire is coiled as shown in the figure. It may be coated with an insulator such as ceramic or plastic, and in this case, the surface of the insulator as a coating layer is formed with irregularities by an appropriate method such as making a slit-like cut to contact the test liquid. The surface may be a non-smooth surface.

In order to check the adhesion of the slime or scale, as shown in FIG. 1, the resistance bulb 1 is immersed in a test liquid (water) at an arbitrary point such as a pipe 10 of an actual process water system. A slime or scale adhesion detecting device is installed in the temperature measuring unit 2 and the temperature of the resistance temperature detector 1 is measured.
The determination unit 3 determines the slime or scale adhesion state from the measured temperature, and displays the result on the display unit 4.

Specifically, the detection of slime adhesion is carried out according to the following procedures.

The resistance temperature detector 1 having no adhered substance on the surface is immersed and installed in the test solution, and is not energized at all for one hour. After one hour, a constant current of a predetermined value or more is applied to the resistance bulb 1 for one minute. The constant current equal to or more than the predetermined value is
The current value (constant value) is such that the temperature of the resistance temperature detector 1 is preferably 40 to 100 ° C, particularly preferably 40 to 90 ° C, particularly preferably 50 to 80 ° C. Almost simultaneously with the start of energization, the voltage applied to the resistance temperature detector 1 rapidly rises to reach an equilibrium temperature. The applied voltage when the temperature reaches the equilibrium temperature or the applied voltage after a predetermined time (for example, one minute) has elapsed after the start of energization is measured by the voltage measurement unit. After reaching the equilibrium temperature, a certain interval (for example, 1 second)
By averaging the voltage values measured a plurality of times (for example, 40 times), more accurate measurement can be performed. Based on the voltage measured by the voltage measuring section 6, the temperature calculating section calculates the temperature of the resistance bulb 1 and sends the temperature data to the determining section 3. The determination unit 3 determines the presence or absence of slime and the amount of slime based on the temperature data. The display unit 4 displays the determination result of the determination unit 3. After a preset time (for example, one minute) has elapsed after the start of energization, the energization to the resistance temperature detector 1 is stopped. After one hour has passed, the determination of slime adhesion is again performed according to the procedure described in (1).

In the above, the voltage after a lapse of a predetermined time after the start of energization is measured, and the slime adhesion state is determined based on the measured voltage. mV / msec), and the slime adhesion state may be determined based on the determination result.

In the above procedures (1) to (4), a constant current of a predetermined value or more is applied to the RTD 1 once an hour for a short time (for example, one minute), and during a period other than the current application time (for example, one hour). During the period, no current is supplied to the RTD 1 at all. However, in the present invention, a minute constant current may be supplied to the resistance bulb 1 during this one hour. The minute constant current is set so that the surface temperature of the resistance temperature detector 1 is higher than the temperature of the water and does not hinder the generation of slime, for example, 30 to 37 ° C. When a minute current is continuously supplied in this way, a minute constant current generator may be provided separately from the constant current generator 5, and a minute constant current may be supplied to the resistance temperature detector 1 via the switching circuit. .

The detection of the adhesion of the scale is performed by detecting the temperature of the resistance temperature detector 1 as a constant current of a predetermined value or more in the above-described method. What is necessary is just to set the current value so as to be 60 to 100 ° C.

Needless to say, the scale and slime can be detected simultaneously. The threshold value used as a criterion in the determination unit 3 is determined based on the concentration of the water-based hardness component, concentration ratio, turbidity,
D, it can be arbitrarily set in consideration of the slime-forming microflora, the allowable scale, the amount of slime attached, and the like.

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

Further, the resistance thermometer may be always installed in the water system to be used for continuously monitoring the slime or scale adhesion state. It can also be used to evaluate the performance of slime inhibitors or 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, when the adhesion of the slime or scale is detected by the slime or scale adhesion detection device of the present invention, if the aqueous system is such that the inside of the system is washed with the slime remover or scale remover, the supplied slime or scale is supplied. Since the RTD is washed with the slime remover or the scale remover, there is no need to separately wash the RTD.

In the present invention, the presence or absence of the test solution may be measured by a level sensor, and the test solution may be energized only when the resistance temperature sensor is immersed in the test solution. By doing so, burning of the resistance bulb can be prevented.

In the above embodiment, a relatively large constant current is applied for about one minute per hour. However, this "one hour" or "one minute" is merely an example, and other times may be used. Is clear.

[0041]

As described in detail above, according to the slime or scale adhesion detecting device of the present invention, the presence or absence of slime or scale adhesion and the amount of slime or scale adhesion can be determined based on the following effects. Detection can be performed with high accuracy from the initial stage of scale generation.

Since the sensor (thermometer) is small, the device can be directly installed during the actual process, so that the slime or scale adhesion state can be accurately detected under the actual system conditions; Because the body is small, the device can be installed anywhere in the actual process. In addition, the equipment can be installed without large-scale modification of the actual process; the installation area can be reduced because the equipment can be reduced in size; it is possible to continuously detect the slime or scale adhesion status online. It is possible to place multiple sensors (resistance temperature detectors) in the actual process, so that the state of slime or scale deposition between arbitrary multiple positions and It is also possible to detect a difference in adhesion speed and the like.

Therefore, according to the present invention, it is possible to accurately grasp the state of adhesion of water-based slime or scale and control the injection of a slime control agent or a scale inhibitor, thereby preventing slime or scale adhesion failure. It is possible to reliably prevent it.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a slime or scale adhesion detecting device according to the present invention.

FIG. 2 is a block diagram illustrating an embodiment of a temperature measuring unit according to the present invention.

3A and 3B are explanatory views showing an embodiment of a resistance temperature detector according to the present invention, wherein FIG. 3A is a plan view and FIG. 3B is a cross-sectional view taken along line BB of FIG. is there.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 resistance temperature detector 2 temperature measurement unit 3 judgment unit 4 display unit 5 constant current generation unit 6 voltage measurement unit 7 temperature calculation unit 8 conduction control unit 11 insulating substrate 12 platinum pattern 13 coating layer

Claims (1)

[Claims] A temperature measuring resistor provided so that a surface thereof is in contact with a test liquid; an energizing means capable of energizing the temperature measuring resistor;
A slime or scale adhesion detection device comprising: a control means capable of controlling an amount of current supplied from the current supply means, wherein a surface of the temperature measuring resistor which is in contact with a test liquid is a non-smooth surface. A slime or scale adhesion detecting device, characterized in that: