JPH0979975A - Managing method for corrosionproof film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately monitor iron content rate and iron content by monitoring the iron content rate or iron content in corrosionproof film by using hue angle. SOLUTION: A light emitting fiber cable 6 and a light receiving fiber cable 7 are provided at the side of a scope 8. The fiber scopes are formed in watertight structures, pressed to a measuring point 11 in a measuring pipe 9, and fixed. The light emitted from a light emitting unit 3 with a C light source of a pulse xenon lamp as an observing light source is reflected at the point 11 by using a prism 10 from the cable 6. The reflected light is passed through the cable 7, A-D converted by a microcomputer 1 via a spectroscope 4 and a photoreceiver 5, a hue angle is calculated, and displayed as iron content rate and iron content on a display 2. The angle is captured at the change of the color of a yellowish copper or copper alloy equipment surface to reddish color by the formation of the iron film as the reduction of the angle (90 deg. yellow to 0 deg. red).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to copper or copper alloy equipment, specifically condenser copper, copper alloy cooling pipe inner surfaces for heat exchangers such as oil refining equipment, copper alloy water pipe inner and outer surfaces, and other seawater, The present invention relates to a method for controlling an anticorrosion film of various devices that come into contact with electrolytes such as fresh water and soil.

[0002]

2. Description of the Related Art Conventionally, for the corrosion protection of copper or copper alloy equipment as described above, iron ions are supplied into an electrolyte such as seawater,
A method of forming an iron film on the equipment surface is used. In order to evaluate the corrosion resistance of the anticorrosion coating formed on the equipment surface in such an anticorrosion method, the iron content in the formed coating must be analyzed, and the operation of the device is stopped to cut out the equipment surface. Etc., for example, in the case of a heat exchanger cooling pipe, it is necessary to pull out the pipe, which has a problem that it takes a lot of time and cost, and easily and quickly evaluates and manages the anticorrosion property of the anticorrosion coating. There was a need for a method that could.

Therefore, the inventors of the present invention first disclosed in Japanese Patent Laid-Open No. 7-1.
In Japanese Patent Publication No. 27993, in order to solve the above-mentioned problems, an anticorrosion management method capable of monitoring the iron content of the iron-containing anticorrosion coating of the heat exchanger cooling pipe in real time during operation of the heat exchanger was proposed. In the invention described in this publication, the iron content in the iron film is evaluated by a colorimetric value. That is, in this prior invention, the fact that the color of the inner surface of the copper alloy tube is reddish due to the formation of the iron film has been obtained as a visual observation finding, and thus from the three attributes of color, hue, lightness and saturation. The saturation in a certain direction of the hue in a color solid that is formed, specifically, the red direction is managed by evaluating the saturation (a *) in the L * a * b * color system.

[0004]

However, in the invention described in the above publication, the iron content of the anticorrosion coating is evaluated by the saturation (a *) in which the hue in a fixed direction only in the red direction is fixed. However, the film did not show a reddish color change (change in hue) due to the formation of. Therefore, when the change in the iron content in the coating due to the formation of the anticorrosion coating is difficult to appear as the change in the saturation of the color system due to the change in the surface state (dry state, wet state) of the measurement object. In some cases, there was a problem in controlling the anticorrosion coating.

[0005]

The present invention is to solve the above technical problems, and the iron content in the anticorrosion coating as described above formed for the purpose of anticorrosion of equipment made of copper or copper alloy. And to provide a method for controlling an anticorrosion coating that enables more accurate real-time monitoring of the iron content than before, and to monitor the iron content or the iron content in the anticorrosion coating using the hue angle. By the above, the above-mentioned object is achieved.

Further, the present invention has a feature that the amount of iron ions supplied by the above-mentioned monitoring is adjusted and the anticorrosive film is controlled, thereby achieving the initial problem.

[0007]

FIG. 1 is a conceptual diagram of the hue in the color solid. The hue is counterclockwise (every 90 °) with respect to the saturation (a *) in the red direction, and the hue in the yellow direction, It constitutes a plane on which the saturation in the green direction and the saturation in the blue direction are located. Using this hue angle, the saturation axis in the red direction is 0 ° (reference), the saturation axis in the yellow direction is 90 °, and the saturation axis in the green direction is 1.
The hue can be represented by a numerical value such that the saturation axis is 270 ° at 80 ° and the blue direction. The present invention uses this hue angle,
The change in color from the yellowish copper or copper alloy equipment surface to the reddish color due to the formation of the iron film is taken as the decrease in the hue angle (from 90 ° (yellow) to 0 ° (red)) Catch,
Accurate evaluation can be realized by evaluating the iron content and the iron content in the iron film with the value of this hue angle.Therefore, the formation state of the anticorrosion film is grasped and controlled in real time during operation, and the value is supplied. It is possible to further adjust the amount of iron ions to be used, and it is possible to accurately control the anticorrosion coating.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a management method according to the present invention will be described.
The present invention will be described in more detail with reference to an example applied when iron ions are supplied to a seawater heat exchanger to form an anticorrosion coating on the inner surface of a copper alloy tube of the heat exchanger.

FIG. 2 is a schematic explanatory view of a color difference meter used in the embodiment. In FIG. 2, 1 is a microcomputer unit, 2 is a display unit, 3 is a light emitting unit, 4 is a spectroscope unit,
Reference numeral 5 is a light receiving portion, 6 is a light emitting fiber cable, 7 is a light receiving fiber cable, 8 is a scope portion, 9 is a measuring pipe, 10 is a prism, 11 is a measuring point, and 12 is a spacer. The main body of the color difference meter is manufactured by Minolta Co., Ltd.
Based on the CT-310 colorimeter, a modified version of the scope was extended with an optical fiber cable (2 m).

In the apparatus used in this experiment shown in FIG. 2, a light emitting fiber cable 6 and a light receiving fiber cable 7 are provided on the side surface of a scope portion 8, and these fiber scopes have a watertight structure and inside a measuring pipe 9. Measurement point
It is pushed into 11 and fixed. At the time of measurement, a pulse xenon lamp is used as the light source, and the light emitted from the light emitting unit 3 using the c light source as the observation light source is reflected from the light emitting fiber cable 6 at the measurement point 11 using the prism 10 and the reflected light is received. After passing through the fiber cable 7 and A / D converted by the microcomputer unit 1 via the spectroscope unit 4 and the light receiving unit 5, the hue angle is calculated, and the iron content and the iron content are calculated, for example, the display unit 2 It is designed to be displayed on.

FIG. 3 shows an experimental procedure for the correlation between the measured value by the color difference meter and the iron content (iron content). The scope section 8 of the color difference meter equipped with the spacer 12 corresponding to the diameter of the copper tube is placed in the measuring pipe 9 made of the copper tube.
Push in 30 cm. The spacer 12 is for fixing the scope portion 8 in the copper tube and performing stable color difference measurement. Color difference measurement was performed at 4 points (intervals of 90 °) in the circumferential direction, and the average value of the 4 measured points was taken as the relevant measured value. Further, by pushing in 30 cm, the same color difference measurement was performed in the same manner as above. In this experiment, the L * C * h ° color system and the L * a * b * color system were measured.

In FIG. 3, copper tubes were sliced at 1 cm intervals from the locations where color difference measurements were made at intervals of 30 cm, and used as samples for measurement. The cut copper tube was immersed in 10% hydrochloric acid to completely elute the anticorrosion coating, and then the total iron contained in the solution was analyzed by ICP emission spectroscopy. The iron content was determined by dividing the total iron amount determined by ICP by the weight loss of the copper pipe due to the dissolution of the anticorrosion coating (total coating weight). Also, the iron content was obtained by dividing the total iron amount obtained by ICP by the area analyzed.

FIG. 4 shows the saturation (a in the red direction of the L * a * b * color system.
A correlation diagram between *) and iron content is shown. In addition, in Figure 5, L * C * h
A correlation diagram between the hue angle (h °) of the colorimetric system and the iron content is shown. 4 and 5, the iron content (Wt) can be represented as a first-order approximation of colorimetric values, and the respective linear regression equations are as follows. Wt = -1.724 + 0.979 x a * (correlation coefficient is r = 0.66) Wt = 13.5-0.135 x h ° (correlation coefficient is r = 0.93)

Comparing the two, it was found that the evaluation at the hue angle (h °) was higher than the evaluation at the saturation (a *) in the red direction in terms of the correlation coefficient. That is, it was shown that the iron angle was evaluated more accurately by the hue angle (h °) than the saturation (a *) in the red direction, regardless of whether the sample surface was dry or wet.

FIG. 6 shows the saturation (a in the red direction of the L * a * b * color system.
The correlation diagram between *) and iron content is shown. Furthermore, in Figure 7, L * C * h
A correlation diagram between the hue angle (h °) of the colorimetric system and the iron content is shown. The iron content (W) in each of FIGS. 6 and 7 can be represented as a linear approximation of the colorimetric value, and the respective linear regression equations are as follows. W = -171.6 + 45.5 x a * (correlation coefficient is r = 0.76) W = 600-7.12 x h ° (correlation coefficient is r = 0.93)

Comparing the two, it was found that the evaluation at the hue angle (h °) was higher than the evaluation at the saturation (a *) in the red direction in terms of the correlation coefficient. That is, it was shown that the iron content was evaluated more accurately by the hue angle (h °) than the saturation (a *) in the red direction, regardless of whether the sample surface was dry or wet.

In the above embodiment, the case where iron ions are supplied to the seawater heat exchanger to form the anticorrosion coating on the inner surface of the copper alloy tube of the heat exchanger has been described, but the present invention is concerned with these heat exchanges. Needless to say, it can be widely applied not only to the anticorrosive film on the inner surface of the copper alloy tube of the container, but also to the control of a wide variety of anticorrosive film on the surface of various equipment made of copper or copper alloy. Therefore, it can be accurately applied when the color of the anticorrosion surface changes sequentially to the color of the anticorrosion film as the anticorrosion film is formed. The type of anticorrosion body and the type of anticorrosion coating are not limited.

[0018]

As described above, according to the present invention, since the control of the anticorrosion coating on the equipment surface made of copper or copper alloy is carried out by monitoring the hue angle, it has the following effects. (1) The iron content can be expressed as a first-order approximation of the hue angle, and its first-order regression equation is Wt = 13.5−0.135 × h
At °, the correlation coefficient (r) is 0.93, which is extremely large and a more accurate approximation can be obtained. (2) The iron content can be expressed as a first-order approximation of the hue angle, and its first-order regression equation is W = 600−7.12 × h °,
The correlation coefficient (r) is 0.93, which is extremely large, and a more accurate approximation value can be obtained. (3) Accurate evaluation is possible regardless of the dry or wet state of the iron film surface.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of hue in a color solid.

FIG. 2 is a schematic explanatory view of an example device in which the method for controlling an anticorrosion coating according to the present invention is applied to the inner surface of a copper alloy tube of a seawater heat exchanger as an anticorrosion coating.

FIG. 3 is a perspective explanatory diagram showing a procedure for measuring color difference in the embodiment shown in FIG.

FIG. 4 shows a correlation diagram between saturation (a *) in the red direction and iron content in the L * a * b * color system.

FIG. 5 shows a correlation diagram between the hue angle (h °) of the L * C * h ° color system and the iron content.

FIG. 6 shows a correlation diagram between saturation (a *) in the red direction and iron content in the L * a * b * color system.

FIG. 7 shows a correlation diagram between the hue angle (h °) of the L * C * h ° color system and the iron content.

[Explanation of symbols]

 1 Microcomputer part 2 Display part 3 Light emitting part 4 Spectrometer part 5 Light receiving part 6 Light emitting fiber cable 7 Light receiving fiber cable 8 Scope part 9 Measuring pipe 10 Prism 11 Measuring point 12 Spacer

Claims (2)

[Claims] 1. An anticorrosion method for a device made by supplying iron ions to a device made of copper or a copper alloy to form an anticorrosion film on the surface of the device, wherein the iron content or the iron content in the anticorrosion film is the hue angle. A method for controlling an anticorrosion film, which is characterized by being monitored by using it. 2. The method for controlling an anticorrosion coating according to claim 1, wherein the amount of iron ions is adjusted by the monitoring.