JPH04134234A - Leaking-liquid detecting sheet - Google Patents

Abstract

PURPOSE:To obtain a leaking-liquid detecting sheet for visual discovery, by setting a discoloration region of an acid-base 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 an objective detecting area. CONSTITUTION:An electrode 2 consists of two kinds of metal wires differing in electrode potential for an objective detecting liquid, for example, saltwater. An acid-base indicator impregnated in a liquid-absorbing cloth exhibits an acid color when a pH of an objective detecting liquid after electrolysis is below a discoloration region, a basic color, i.e., the indication color, when the pH exceeds the region and a mixed color of the two when it is within the region, That is, if the objective detecting liquid is saltwater, it becomes strong alkaline reaching the coloration 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 detecting liquid and a cleaning agent can be performed by the visual confirmation.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for detecting liquids to be detected, especially electrolyte solutions such as salt water or salt aqueous solutions (hereinafter referred to as salt water), when leaking onto a floor surface or the like. The present invention relates to a liquid leakage detection sheet that can distinguish between normal water leakage and spraying of a cleaning agent used for cleaning floors, etc., and can quickly find the location of the leakage.

[Conventional technology]

In recent years, it has become common to transport seafood and the like 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.

In order to detect such leakage of liquid to be detected, a liquid leakage sensor that detects leakage of liquids such as water and oil can be repurposed.For example, if these liquids leak between two conductive wires, In such a case, there is a method for detecting leakage by electrically detecting the change in electrical resistance or capacitance (see, for example, Japanese Utility Model Publication No. 56-43940). and,
In order to identify the location, there is a method of attaching a position detection/output line between the two conductive wires and identifying the location using a section detection method or the like.

Problems to be Solved and Attempted by Invention J] 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. Also, it cannot be used in cases where the use of electrical means is prohibited for explosion-proof or other safety reasons. Furthermore, increasingly complex electrical equipment is required to detect only salt water and not ordinary water or cleaning agents such as floor surfaces. In cases such as the above-mentioned transportation by aircraft, a leakage sensor that requires complicated operations is not suitable, and a sensor that can be detected at a glance by an amateur, or a disposable sensor that can identify the leakage and its location with a simple confirmation operation, is not suitable. A liquid leakage detection sheet 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 provides a liquid leakage detection sheet that can visually detect the leakage point of a liquid to be detected such as salt water, distinguishing it from leakage of water or cleaning agent. This is what we are trying to provide.

[Means to solve the problem]

In order to achieve the above object, a liquid leakage detection sheet of the present invention has at least an electrode whose surface is made of a metal that has a different electrode potential with respect to the liquid to be detected, and a planar body in contact with the electrode. At least one sheet of the planar body in contact with the electrode is made of a liquid-absorbent cloth impregnated with an acid-base indicator, and the range of color change of the acid-base indicator includes the PH range after electrolysis of the liquid to be detected. , does not include the pH range of the cleaning agent used to clean the area to be detected.

The above-mentioned electrode may be one in which one or more pairs of metal wires whose surfaces have different electrode potentials with respect to the liquid to be detected are arranged side by side, and each pair is short-circuited at at least one point or more in a planar arrangement. There is one in which at least the surfaces of metal wires having different electrode potentials with respect to the liquid to be detected are alternately arranged in a grid pattern and cross- short-circuited.

Further, there are those in which the electrode is sandwiched between two planar bodies, and those in which the electrode is woven into a liquid-absorbing cloth.

[Effect]

When salt water, the liquid to be detected, leaks, it soaks into the absorbent cloth. Since this liquid-absorbing cloth is in contact with electrodes made of metals having different electrode potentials, a difference in electrode potential occurs between these electrodes, causing current to flow. Then, strong alkaline NaOH is formed on the side where the electrode potential is higher by electrolysis of the detection target liquid such as salt water. In addition, the cloth is impregnated with an acid-base indicator (or a base indicator in the case of an alkali) that changes color in the pH range of the detection target liquid after electrolysis, so this NaOH and the base indicator react to give the indicator color.

On the other hand, even if water from a non-electrolyte solution leaks, it simply soaks in and does not change color.

Further, even if a cleaning agent for cleaning the floor surface etc. flows in, the cleaning agent is weakly alkaline or slightly acidic and the pH does not change much, so the acid-base indicator does not change color in that PH range. Therefore, if salt water or the like to be detected leaks, it will display an indicator color so that the leak and its location can be seen at a glance.

(Example) Hereinafter, the present invention will be explained in detail based on the drawings.

Fig. 17 is a perspective view of the liquid leakage detection sheet, Fig. 2 is a diagram showing the arrangement of electrodes and the short circuit state, Figs. 3 to 6 are perspective views of other liquid leakage detection sheets, and Fig. 7 is a liquid leakage detection sheet. It is a figure which shows the usage state of a sheet|seat.

In FIG. 1, a leakage detection sheet 1 has an electrode 2 sandwiched between upper and lower planar bodies 3 and 4 and covered therewith.

The electrode 2 is made of two types of metal wires that have different electrode potentials relative to the liquid to be detected, such as salt water, such as a copper wire 2a and an aluminum wire 2b.
A pair of these are short-circuited at one end 2c. A large number of pairs of such metal wire electrodes 2 are arranged in parallel to form a plane, and are arranged so that electrolysis by the metal wire electrodes 2 occurs no matter where salt water leaks. Note that the metal wire electrode 2 is not limited to one with a round cross section, and various types such as a flat one with an elliptical cross section, a foil type one with a rectangular cross section, etc. are used. The metal wire constituting the electrode 2 may have a different electrode potential only on its surface, such as a copper:gL wire and an aluminum yi steel wire.

Among the upper and lower planar bodies 3 and 4, at least the upper surface 3 may be made of liquid-absorbing cloth impregnated with a specific acid-base indicator described below. The lower surface 4 may be made of a similar cloth, but it is also possible to use a common plastic flame-retardant flooring material because of its water retention and strength properties.

The liquid-absorbing cloth is preferably one made of an organic synthetic fiber containing polymetaphenylene isophthalamide as a main component (for example, Cornesox (registered trademark) manufactured by Teijin Ltd.). 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 Cornenox, 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.

Next, as the acid-base indicator to be impregnated with the liquid-absorbing cloth S, for example, those shown in Table 1 B are used.

When the pH of the detection target liquid after electrolysis is below the discoloration range, it exhibits a highly 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 thorium anthraquinone-2-sulfonate in an alkali and neutralizing it with sulfuric acid. Indigo carmine is a dye obtained, for example, by sulfonating indigo using concentrated sulfuric acid or mild oleum.

FIG. 2 is a diagram showing a different arrangement of electrodes and a short circuit state from FIG. 1. As shown in FIG. 2(a), it is also possible to use a staggered electrode 5 instead of a linear electrode, and there is no restriction on the planar shape as long as a short-circuit location is ensured. Also, Fig. 2(b)
As shown in the figure, the short-circuit of the electrode 6 is not limited to only one end, but may be short-circuited alternately at a number of ends. As shown by the dashed line in the figure, no matter where the salt water falls, current flows in the loop closest to it and electrolysis occurs. With this kind of mesh arrangement, even if the leakage detection sheet is cut into small pieces, short-circuit points will be secured.
It can be used as is.

Fig. 3 shows a liquid leakage detection sheet in which metal wires constituting electrodes are woven.The thread 9 made of Conex and the metal wire 2 are mixed together to form the warp, and the thread 7 made of Conex is used as the weft to form an entangled weave. It was made into a cloth shape. The weft filament yarn 7 and the warp filament yarn 9 have good water absorption properties and are also impregnated with an acid-base indicator. In addition,
As for the weaving method, various well-known weaving and knitting methods can be applied.

Figure 4 shows a leakage detection sheet in which foil-shaped metal wires are cross-short-circuited, and the copper foil 8a and aluminum foil 8b of the metal wire 8 are stacked vertically and cross-short-circuited to form a grid-like electrode as a whole. It is something. Note that the upper and lower planar bodies 3.4 are similar to those explained in FIG. 1. Then, when the salt water seeps in, the current shown by the arrow flows within one grid indicated by the leader line, causing electrolysis. This liquid leakage detection sheet has a thinner thickness and has a shape that allows it to be easily cut to a required size and used as a disposable sheet.

FIG. 5 shows a liquid leakage detection sheet with a liquid-soluble display material added thereto. In other words, compared to the sheet shown in FIG. The 0 display material 9, which is sandwiched and integrated between the planar bodies 3.4, is made by impregnating a linear material such as a thread, a string, and a paper tape with an indicating agent such as a coloring agent or a luminescent material. The agent dissolves in water or detergent and is designed to elute at least a color that can be clearly distinguished from the color of the cloth of the upper sheet 3. Therefore, if there is a water leak, whether it is salt water or water, even if the leaked area dries, the color of the indicator will remain dissolved on the surface of the planar body 3 in that area, and the leakage will occur. You can search for the location later. Even if the color of the acid-base indicator disappears, the leaked part can be soaked with water and tested to see if it takes on the color of the acid-base indicator again. If it does not show the color of the indicator, it is simply water leakage or cleaning agent, and if it shows the color of the indicator, it is salt water and the surrounding area needs to be cleaned. Incidentally, as in the case of FIG. 3, warp threads impregnated with an indicator agent may be woven between the electrodes as the indicator material 9. Additionally, those with a liquid-soluble indicator added are, in principle, disposable.

FIG. 6 shows a leak detection sheet to which a non-liquid soluble display material is added. That is, compared to the one shown in FIG. 1, a non-liquid soluble display material 10 is provided between the electrodes 2, and similarly to the electrodes 2, they are held and integrated by the upper and lower planar weights 1.4. Further, the upper sheet 11 not only has a liquid absorbing property that conducts leakage through capillary action, but also uses a transparent multifilament yarn or spun yarn that becomes transparent due to this liquid absorption. Therefore, although the planar body 11 is opaque in a dry state due to diffused reflection, it becomes transparent due to liquid absorption, and the non-liquid soluble display material 10 inside appears transparent.

This display material 10 is selected to have a color that can be clearly distinguished from the color of the cloth constituting the planar body 11. Therefore, if there is a water leak, whether it be salt water, water or cleaning agent, the leaked area will be clearly visible. The water leak location can be inspected in detail to see if it exhibits the color of an acid-base indicator.
The color of the cloth of the sheet 11 is suitable for a liquid leakage detection sheet used on a floor surface, etc., where it can be confused with an indicator.

For example, if you use it in a place where there is a possibility of frequent spills,
If it's water, just leave it as it is and it will dry and return to its original state. In addition, as in the case of FIG. 3, the display material 7 made of a colored plastic string can also be used and woven between the electrodes.

That's all for the explanation of Figure 7! FIG. 7(a) shows an example of how the i-liquid detection sheet is used, in which it is spread over the floor 16 below the entire cargo 12. The liquid leakage detection sheet 13 may be cut to a predetermined size and placed below the area where leakage is expected to occur. For example, 1j in Figure 5
An R liquid detection sheet or the like is used. FIG. 7(b) shows an example of use in which the leak detection sheet 15 is spread over the entire cargo compartment where the salt water tank 14 is located. For example, a liquid leakage detection sheet as shown in FIG. 5 is used.

Although the above explanation deals with salt water as the liquid to be detected, the liquid to be detected is not limited to salt water. In other words, if the liquid to be detected is an electrolyte liquid, the electrode material and acid-base indicator should be appropriately selected. The present invention can be applied by selecting the following.

[Effects 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.

And, it contains electrodes with different electrode potentials with respect to the liquid to be detected using an acid-base indicator! Pole 2.・When brought into contact with a liquid-absorbing cloth, the color change range of this acid-base indicator includes the PH of the detection target liquid after electrolysis, but does not include the PH of the cleaning agent used to clean the detection target area. When salt water, etc. leaks, electrolysis generates NaOH, etc., which gives an indicator color.On the other hand, even if water or cleaning agent soaks in, the indicator color does not appear. It can be confirmed at a glance by distinguishing it from the dispersion, and anyone can detect it quickly and easily without adjusting any electrical equipment.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the liquid leakage detection sheet, Figure 2 is a diagram showing the arrangement of electrodes and short-circuit conditions, Figures 3 to 6 are perspective views of other liquid leakage detection sheets, and Figure 7 is a diagram showing the arrangement of electrodes and short-circuit conditions. This is a diagram showing the usage status of the detection sheet. Note that explanations of main symbols in the drawings are as follows. 1.13.15...Leakage detection sheet, 2.5, 6.8
... Electrode, 3, 4... Planar body. Patent applicant: TAC Electric Cable Co., Ltd. Agent: Yoshiyuki Kaji, patent attorney Figure 2

Claims (5)

[Claims] (1) A liquid leakage detection sheet having at least an electrode whose surface is made of a metal having a different electrode potential with respect to a liquid to be detected, and a planar body in contact with the electrode, wherein at least one of the planar bodies in contact with the electrode The sheet is made of a liquid-absorbent cloth impregnated with an acid-base indicator, and the color change range of the acid-base indicator includes the PH range after electrolysis of the detection target liquid, and includes the PH range of the cleaning agent used to clean the detection target area. A liquid leakage detection sheet that is characterized by no leakage. (2) The liquid leakage detection sheet according to claim 1, wherein the electrode is one in which at least one pair of metal wires at least on the surface of which have different electrode potentials with respect to the liquid to be detected are arranged in parallel;
A liquid leakage detection sheet characterized in that each pair is short-circuited at at least one point or more and arranged in a plane. (3) The liquid leakage detection sheet according to claim 1, wherein the electrode is formed by alternately arranging metal wires having different electrode potentials with respect to the liquid to be detected on the surface thereof in a grid pattern and cross-circuiting them. Characteristic liquid leakage detection sheet. (4) The liquid leakage detection sheet according to claims 1 to 3,
A liquid leakage detection sheet characterized in that an electrode is sandwiched between two planar bodies. (5) The liquid leakage detection sheet according to claims 1 to 3,
A liquid leakage detection sheet characterized by electrodes woven into liquid-absorbing cloth.