JPH04134236A - Leaking liquid sensor - Google Patents

Abstract

PURPOSE:To visually differentiate a leaking position of an objective detecting liquid, such as saltwater, from leakage of water of a cleaning agent by setting a discoloration region of a basic indicator to include a pH region of an objective detecting liquid after electrolysis and not to include a pH region of a cleaning agent for cleaning a pH region of a cleaning agent for cleaning an objective detecting area. CONSTITUTION:A leaking liquid sensor 1 comprises a metal foil 2, a conductive coating material 3 printed on the metal foil 2 and a liquid-absorbing sheet-like body 2 attached thereon. When a pH of an objective detection liquid after electrolysis is below a discoloration region, an acid color is exhibited, when it exceeds the discoloration region, a basic color as the indication color is exhibited, and when it is within the discoloration region, a mixed color of the two is exhibited. That is, if an objective detecting liquid is saltwater, it becomes strong alkaline reaching the discoloration region after electrolysis. However, because a cleaning agent is normally weak alkaline or weak acid, not containing an electrolyte, and does not discolor, the differentiation between a corrosive objective sensing liquid and a cleaning agent can be performed by the visual confirmation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to the electrolysis of a liquid to be detected, especially a saline solution or an aqueous salt solution (hereinafter referred to as salt water). If a solution leaks onto a floor surface, etc., it can be distinguished from an ordinary water leak that is a non-electrolyte solution or the spraying of a cleaning agent used for cleaning floors, etc., and the location of the leak can be quickly found. [Technology] In recent years, it has become common to transport seafood, etc. alive, and therefore salt water tanks that store large amounts of salt water have come to be used at transportation sites. In a normal freight vehicle, even if some salt water leaks from the salt water tank onto the floor, the leak can be stopped as soon as the leak is noticed and the leaked salt water can be washed away. However, when transporting by aircraft, it is necessary to immediately detect and respond to leaks of salt water due to limitations in the materials and structures that make up the aircraft.

In other words, in cases such as aircraft where deterioration due to corrosion or the like in aircraft body constituent materials may lead to serious accidents, it is necessary to discover leaks early and completely flush them out in order to prevent them from occurring.

As such a liquid leakage sensor that detects liquid leakage, a liquid leakage sensor that detects liquid leakage such as water or oil can be used. For example, if these leaked liquids enter between two conductive wires, there are devices that detect the leakage by electrically detecting changes in the electrical resistance or capacitance (for example, Utility Model No. 06 43940). (see official bulletin).

In order to specify the location, there is a method that further attaches a position detection line between the two conductive wires and uses a section detection method or the like to specify the location.

[Problem to be solved by the invention]

The electrical leakage sensor described in the prior art uses electrical means such as energization, and therefore requires complex electrical control equipment for analysis and display. Therefore, there is a problem in that maintenance and inspection by skilled operators are required to maintain good operating conditions at all times. In addition, it cannot be used in cases where the use of electrical means is prohibited for explosion-proof or other safety reasons.Furthermore, in order to detect only salt water and not detect ordinary water or cleaning agents on the floor etc. , increasingly complex electrical equipment is required. In cases such as the above-mentioned transportation by aircraft, leakage sensors that require complicated operations are not suitable, and sensors that can be detected at a glance by an amateur or that can identify saltwater leaks and their locations with a simple confirmation operation, such as disposable ones, are not suitable. A liquid leakage sensor with a simple structure is desired, and the use of electrical means itself is not desirable.

The present invention has been made in view of the above-mentioned problems of the conventional technology, and can visually detect the leakage point of a detection target liquid such as salt water by distinguishing it from a leakage of water or a cleaning agent, and is also disposable. The present invention aims to provide a liquid leakage sensor with a simple structure.

[Means for Solving the Problems] In order to achieve the above object, the liquid leakage sensor of the present invention includes a conductive metal powder containing metal powder having an electrode potential different from that of the metal foil with respect to the liquid to be detected, on a metal foil. The paint is discretely printed in the form of a strip, a grid, or a polka dot pattern, and a liquid-absorbing sheet material impregnated with an acid-base indicator is adhered thereon, and the discoloration range of the acid-base indicator is PH after electrolysis of detection target liquid
range, but does not include the PH range of the cleaning agent used to clean the area to be detected.

[Effect]

When salt water, the liquid to be detected, leaks, it soaks into the liquid-absorbing planar body. Underneath this liquid-absorbing sheet, conductive paint with a different electrode potential from that of the metal foil is discretely printed on the metal foil in the form of strips, grids, or polka dots, so salt water can When it penetrates to the bottom of the sheet, a difference in electrode potential occurs between the metal foil and the conductive paint, and a current flows through the salt water impregnated in the sheet, electrolyzing the salt water and moving it to the side with a higher electrode potential. Strongly alkaline NaOH is formed. Further, since the planar body is impregnated with an acid-base indicator (a base indicator in the case of an alkali), this NaOH and the base indicator react to exhibit an indicator color. On the other hand, even if non-electrolyte water leaks, it just soaks in and does not develop color.Also, even if a cleaning agent used to clean floors etc. flows in, the cleaning agent is weakly alkaline or acidic and the pH does not change much. The acid-base indicator does not change color in that pH range, so it takes on an indicator color only when the salt water to be detected leaks, allowing the leak and its location to be displayed at a glance.

〔Example〕

Hereinafter, the present invention will be described in detail based on the drawings. FIG. 1 is a perspective view of a liquid leakage sensor, and FIG. 2 is a diagram showing the usage state of the liquid leakage sensor.

In FIG. 1, a liquid leakage sensor 1 consists of a metal foil 2, a conductive paint 3 printed on the metal foil 2, and a liquid-absorbing sheet 4 stuck on top of these. It is.

As the metal foil 2, a relatively inexpensive material such as aluminum foil, which is free from rust, is used.

As the conductive paint 3, one containing metal powder having an electrode potential different from that of the metal foil 2 with respect to the liquid to be detected is used. When the metal foil 2 is aluminum, a copper powder type conductive paint is most suitable. Such copper powder type conductive paint is disclosed in Japanese Unexamined Patent Publication No.
-100 parts by weight of metallic copper powder, ■35-50% by weight of melamine resin, 20-35% by weight of polyester resin, and 15-30% by weight of resol-type phenolic resin, as disclosed in Japanese Patent Publication No. 167385. Resin mixture 10~
25 parts by weight, and ■ 0.1 to 2 fatty acids or metal salts of fatty acids.
There is a conductive coating material which is made by blending 1.0 parts by weight with 0.5 to 4 parts by weight of a chelate forming agent.

As shown in the first figure, the conductive paint 3 is printed on the metal 7f32 in the form of a strip (for example, strips about 5 in width arranged at intervals of about 5 m) and then fired. Printing can be easily and continuously carried out using a transfer roller or the like, and baking can be carried out in a furnace at about 160° C. for about 30 minutes if the conductive paint has the above composition.

The arrangement of the conductive paint 3 on the metal foil 2 is not limited to the strip shape shown in the first figure, but may also be in the form of a grid or in a polka dot pattern. The arrangement should be such that it can spread across the boundary between the metal foil 2 and the conductive paint 3 when it soaks into the liquid-absorbing sheet 4. Next, the metal foil 2 on which the conductive paint 3 is printed. As an example of the liquid-absorbing planar body 4 to be adhered thereon, a liquid-absorbing cloth impregnated with an acid-base indicator described below is used. As the liquid-absorbing cloth, an organic synthetic fiber containing polymetaphenylene isophthalamide as a main component (for example, Conex (registered trademark) manufactured by Teijin Ltd.) can be used. That is, this Cornenox has excellent heat resistance and flame retardancy, and can be used in places where strict heat resistance and flame retardance are required, such as in aircraft. Note that the threads constituting the cloth are not limited to Cornesox, but multifilament threads such as Tetron, which have excellent liquid absorption properties and can be impregnated with acid-base indicators, and spun threads are selected. Furthermore, the tape is not limited to cloth, and may be a plastic tape that can absorb liquid. Then, such a liquid-absorbing planar body 4 is adhered onto the aluminum foil 2 with a water-insoluble adhesive (for example, synthetic rubber adhesive Bond G17 manufactured by Konishi Co., Ltd.).

Next, as the acid-base indicator impregnated into the liquid-absorbing cloth, for example, those shown in Table 1 are used.

When the pH of the detection target liquid after electrolysis is below the discoloration range, it exhibits an acidic color, when it exceeds the discoloration range, it exhibits a basic color, which is an indicator color, and within the discoloration range, it exhibits a mixed color. That is, if the liquid to be detected is salt, it becomes a strong alkali that reaches the discoloration range after electrolysis.

However, since cleaning agents are usually weakly alkaline or acidic, do not contain electrolytes, and do not change color, it is possible to distinguish and visually confirm the corrosive liquid to be detected and the cleaning agent.

Table 1 Alkali blue is a dye obtained by condensing aniline with tuxin in the presence of benzoic acid or a vanadium catalyst, and sulfonating the resulting product at low temperature. Alizarin blue is a dye obtained, for example, by dissolving sodium anthraquinone 2-sulfonate in alsicarin and neutralizing it with sulfuric acid. Indigo carmine is a dye obtained, for example, by sulfonating indigo with concentrated sulfuric acid or mild oleum.

Next, the operation of the liquid leakage sensor 1 having the above-described structure will be explained with reference to FIG.

In FIG. 1, if salt water, which is the liquid to be detected, leaks in the area indicated by arrow A, the salt water soaks into the liquid-absorbing planar body 4.

Then, it spreads over both the conductive paint 3 and the metal foil 2. Therefore, a difference in electrode potential occurs at the boundary between the metal foil 2 and the conductive paint 3, and a current flows. and,
Salt water, which is an electrolyte solution, is electrolyzed and strong alkaline NaOH is formed on the side where the electrode potential is higher. Further, since the planar body is impregnated with an acid-base indicator (a base indicator in the case of an alkali), this NaOH and the base indicator react to exhibit an indicator color. On the other hand, if non-electrolyte solution water or cleaning agent leaks, it simply soaks in and does not produce color. Therefore, it can be determined at a glance that a predetermined detection target liquid has leaked. This type of liquid leakage sensor is made by sandwiching two types of wire metals with different electrode potentials with respect to salt water, which is the liquid to be detected, between planar bodies impregnated with an acid-base indicator, such as a copper wire and an aluminum wire in parallel. When using wires arranged side by side in a shape, unless the copper wire and aluminum wire are short-circuited at one end, current will not flow and electrolysis will not occur. does not require physical connection. Furthermore, since the structure is simple, consisting of printing a conductive paint onto a metal foil and pasting a liquid-absorbing sheet, continuous production is possible.

FIG. 2 shows how the liquid leakage sensor described above is used, and FIG. 2(a) shows an example in which it is partially spread on the floor 16 below the entire cargo 12. The liquid leakage sensor 13 may be cut to a predetermined size and placed below the area where leakage is expected to occur. FIG. 2(b) shows an example of use in which a leakage sensor 15 is attached to the side surface of the salt water tank 14. In short, it may be installed by laying or pasting at a location corresponding to the i-way of the liquid to be detected.

Note that the above explanation deals with the case of salt water as the liquid to be detected, but the liquid to be detected is not limited to salt water; in other words, if it is an electrolyte liquid, the electrode material and acid-base indicator should be appropriately selected. The present invention can be applied by

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the following effects.

First, it is safe because it does not have electrical means.

The combination of metal foil and conductive paint, which have different electrode potentials with respect to the liquid to be detected, is covered with a liquid-absorbing sheet impregnated with an acid-base indicator, and the color change range of this acid-base indicator is It contains the pH after electrolysis of the detection target liquid, but does not include the pH of the cleaning agent used to clean the detection target area, so if the detection target liquid, such as salt water, leaks, NaOH etc. will be generated due to electrolysis and will take on an indicator color. , even if water or cleaning agent seeps into it, it does not show an indicator color, so you can distinguish leaks of salt water, etc. from simple water leaks or sprayed cleaning agents and check them at a glance, without having to adjust electrical equipment, etc. However, it can be detected quickly and easily. Furthermore, since it has a simple structure of printing conductive paint on metal foil and pasting a liquid-absorbing sheet, it can be manufactured continuously, making it a low-cost liquid leakage sensor, and it can also be disposable. becomes.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the liquid leakage sensor, and FIG. 2 is a diagram showing the usage state of the liquid leakage sensor. Note that explanations of main symbols in the drawings are as follows. 1.13.15=liquid leakage sensor, 2...metal foil, 3...conductive paint, 4...liquid-absorbing planar body. 1st Patent Applicant Tuck Electric Cable Co., Ltd. Agent Yoshiyuki Kaji Patent Attorney Yoshiyuki Kaji 2-3-1 Iwata-cho 2-3-1 Tac Electric Cable Co., Ltd.

Claims (1)

[Claims] (1) A strip of conductive paint containing metal powder having an electrode potential different from that of the metal foil with respect to the liquid to be detected is placed on the metal foil;
It is printed discretely in a grid or polka dot pattern, and a liquid-absorbing sheet material impregnated with an acid-base indicator is attached on top of the printed pattern, and the discoloration range of the acid-base indicator is the same as that of the liquid to be detected. A leakage sensor characterized in that it includes a PH range after electrolysis, but does not include a PH range of a cleaning agent for cleaning a detection target area.