JP2000105187A - Method for measuring contamination of fluid in heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To measure the contamination state of fluid in a short time, and to grasp change in the amount of adhesion of a surface due to continuous usage by measuring the change in the electric resistance of a metal electrode being dipped into the fluid in the pipe of a heat exchanger. SOLUTION: In the measurement of the contamination state of fluid in a heat exchanger, a metal electrode 2 is provided in an internal part 1 of a pipe where the fluid flows. The metal electrode 2 is mounted in a direction crossing the internal part 1 of the pipe or the like, and the signal of the electric resistance is taken into an analyzing device 3. To accurately grasp the amount of adhesion of contamination to the surface of the electrode 2 due to the contamination in the fluid, a plurality of the electrodes 2 are preferably installed. According to the contamination of the fluid in the heat exchanger, the amount of adhesion to the surface of the electrode 2 is changed, and at the same time, an electric resistance value is changed, thus grasping the contamination state of the fluid according to the signal of the electric resistance being taken in from the analyzing device 3. Information for judging whether the contamination of the fluid can block the internal part of the pipe or not can be also obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring contamination of a fluid in a heat exchanger.

[0002]

2. Description of the Related Art Conventionally, heat exchangers have been used for heating or cooling various devices in a chemical plant. In general, as the heat exchanger, a device that performs heat exchange by flowing a secondary medium for heating or cooling the outside of the primary medium of the fluid flowing through the tube bundle is used. In a heat exchanger, the fluid flowing through the tube bundle during its operation often causes deposits on the inner surface of the tube over time, for example, polymer in the fluid, sand and mud in the coolant, and contaminates the inner wall of the tube, thereby reducing thermal efficiency. It is going down. These contaminated heat exchangers result in low-efficiency operation, which sometimes results in reduced capacity and even plugs, which are then operated for cleaning. Will be stopped. For this reason, if there is any extraneous matter, the extraneous substance is attached to the inside of the tube surface to reduce the heat transfer coefficient. This leads to a vicious cycle of promoting deposits on the inner wall of the pipe. Conventionally, as a method for measuring the contamination of a fluid in a heat exchanger, it is known to predict the contamination by a change in the temperature or pressure of the fluid (Japanese Patent Laid-Open No. 54-147894).

[0003]

However, in the above-described method, it takes a considerable time until the temperature or pressure of the fluid flowing in the heat exchanger inner tube changes due to the flow of the fluid, and the contamination state of the fluid changes. In such a case, there is a problem that the contamination of the fluid in that state cannot be measured in a short time.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems relating to the method of measuring the state of contamination of a fluid in a heat exchanger, the present inventor has keenly developed a method of measuring the state of contamination of a fluid in a short time. As a result of the study, when the metal electrode was immersed in the fluid and the electric resistance value was measured, it was found that there was a correlation between the dirt state of the fluid and the electric resistance value, which changed depending on the dirt state of the fluid. It was completed. That is,
The gist of the present invention is a method for measuring the state of contamination of a fluid in a heat exchanger, wherein the change in electrical resistance of a metal electrode immersed in the fluid in the heat exchanger tube is measured. It lies in the method for measuring contamination of fluid in a vessel.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for measuring a contamination state of a fluid according to the present invention will be described in detail with reference to FIG.

FIG. 1 is a sectional view of a measuring apparatus for carrying out the method for measuring the state of contamination of a fluid according to the present invention.
In the figure, reference numeral 1 denotes the inside of a pipe through which a fluid flows, and a metal electrode 2 is provided in a direction transverse to the inside of the pipe 1, and a signal of its electric resistance is taken into an analyzer 3. The metal electrode 2 is not particularly limited as long as it has an electric resistance that changes when dirt in a fluid adheres to the surface of the electrode 2, and materials such as copper, platinum, silver, and nickel are used. Can be used. The electrode 2 is desirably provided with a plurality of electrodes in order to accurately grasp the amount of adhesion to the surface of the electrode 2 due to contamination in the fluid. Further, by providing a plurality of electrodes, it is possible to cope with breakage or damage of the electrodes, and it is also possible to easily replace the electrodes during the measurement.

[0007] Since the amount of adhesion to the surface of the electrode 2 changes due to the contamination of the fluid in the heat exchanger and the electric resistance changes accordingly, the change in the electric resistance is measured immediately. Thus, the amount of adhesion on the surface of the electrode 2 can be accurately grasped.

Further, the analyzer 3 can immediately take in the signal of the electric resistance value of the electrode 2 and not only grasp the dirt condition of the fluid, but also measure it continuously,
The change in the amount of adhesion on the surface of the electrode 2 can be grasped.

As the dirt condition of the fluid increases, the amount of dirt adhering to the electrode 2 also increases, and as a result, the electric resistance value tends to increase. Can be grasped.

With respect to the above-mentioned dirt in the fluid and the change in the electric resistance value of the electrode, a dirt layer is formed on the surface of the electrode due to the dirt in the fluid, and the resistance due to the dirt increases. The “dirt resistance value”, which is the resistance due to the dirt, can be obtained by measuring changes in the current and potential of the electrode. FIG.
Shows an example of the relationship between the "dirt state of fluid" and the "dirt resistance value", and the amount of dirt attached to the electrode increases in accordance with the measured dirt resistance value. The relationship is determined by the material of the dirt in the fluid and the material of the metal electrode.

On the other hand, the relationship between the dirt resistance value and the dirt amount shown in FIG. 2 is continuously displayed on an external recorder through the analyzer 3 so that the operator can easily check the dirt state in the fluid. Can be grasped.

In this way, it is possible to take measures against fluid contamination. That is, the contamination state of the fluid to be handled can be grasped, and information for determining whether or not there is a possibility of closing the inside of the pipe can be obtained. Next, by changing the use condition of the fluid and grasping the change state of the electric resistance value, an appropriate use range can be selected.

Further, by previously obtaining the "dirty state in the fluid" and the "dirt resistance value", it is possible to predict the usage limit of the heat exchanger when the fluid is flowed again in the same state.

[0014]

According to the present invention, the dirt condition of the fluid can be measured in a short time, and the change in the amount of adhesion on the surface can be grasped by continuous use. Further, it is possible to implement a countermeasure against the contamination of the fluid by using the present apparatus.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an example of a measuring device for carrying out the present invention.

FIG. 2 is a graph in which an increase in dirt in a test section is plotted against an electric resistance value.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inside the pipe | tube in the heat exchanger in which the fluid flows 2 Metal electrode 3 Analysis apparatus 4 Electrode support part 5 Electrode core part 6 Tube wall 7 Fluid

Claims (2)

[Claims] 1. A method for measuring the state of contamination of a fluid in a heat exchanger, the method comprising measuring a change in electrical resistance of a metal electrode immersed in the fluid in the heat exchanger tube. A method for measuring the contamination of the fluid inside. 2. The method for measuring contamination of a fluid in a heat exchanger according to claim 1, wherein a plurality of metal electrodes immersed in the fluid are used.