JP2001050856A - Liquid leak sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liq. leak sensor immune to bubbles resulting from contact with a leaking liq. in a case. SOLUTION: A liq. leak sensor 20a comprises at least one reflection boundary surface 4a contactable to a leaking liq. 2 through a gas layer or leaking liq. penetration layer penetrable with the leaking liq. 2, light source means 14a, 14b and light receiving means 28A, 28B. Lights from the light source means 14a, 14b are projected on the reflection boundary surface 4a and received by the light receiving means 28A, 28B, the outputs thereof are arithmetically processed to judge if a leaking liq. 2 exists, and a hollow member having suction holes opened at the gas layer or the leaking liq. penetration layer and exhaust holes opened outside above a specified height of the liq. leak sensor 20a exhausts out from a case 12 bubbles produced in the gas layer or the leaking liq. penetration layer due to the leaking liq. 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the leakage of a liquid having electrical continuity such as water, an acidic solution or an alkaline solution, or a liquid having an insulating property such as organic such as alcohol, thinner or benzene. The present invention relates to improvement of a liquid leak sensor.

[0002]

2. Description of the Related Art In a conventional facility such as a factory, a liquid is supplied by piping. However, since connecting joints are provided at many places in the pipe, liquid often leaks from the joints. Therefore, depending on the type of liquid, humans must constantly monitor the leakage. As such a conventional liquid leakage monitoring method, a conductive method and a liquid amount method are known. Further, Japanese Patent Publication No. 4-70572 discloses that a filter that becomes transparent when absorbing a liquid leak is irradiated with light from a light source.
There is described a liquid leak sensor technology that can detect a liquid leak reliably by detecting a change amount of transmitted light or reflected light from the filter when there is a liquid leak. FIG. 1 is a view showing the principle of such a conventional reflection type liquid leakage sensor 20. A thin paper 8 and a holder 4 of a case 12 are coated on a floor surface 1 with a black bottom surface 4a, and a screw is used as a reflection light absorbing plate. A white thin paper (or cloth, glass, synthetic resin member or the like) 8 is placed thereon. A case 12 whose bottom 12a is made of a transparent or translucent synthetic resin member or a ceramic member such as glass is inserted / attached to the holder 4.
The light source unit 14, the light receiving unit 16 and the detecting unit 18 including a comparator and the like are integrally accommodated in the inside, and are connected to the outside via an electric cable 26. The case 12 also serves as a dust-proof and water-proof lid. However, in order to make it easier for the leaked liquid 2 to penetrate into the central reflection area 8b of the thin paper 8 and to shorten the time for detecting the leaked liquid, the bottom of the case is used. A minute gap 10 is provided between the thin paper 12 and the thin paper 8, and a gap d between the holder bottom surface 4a and the case bottom 12a is provided.
Forms a liquid leakage permeable layer. This gap d is dust,
A few mm to avoid dust and dirt and to detect reflected light from thin paper 8 stably without detecting external noise light.
Within. In addition, it was found that the use of a filter having a structure in which the reflection plate 4a and the case 12 were detachable facilitated replacement and installation work of the thin paper 8. Furthermore, since the location where the liquid leaks cannot be generally specified, the thin paper is generally preferably circular in order to respond quickly to the liquid leaking from any direction. Was. In such a configuration, light 22 is emitted from light source means 14 such as an LED, an infrared laser light emitting element, or an optical fiber, and white reflected light 24 from thin paper 8 is constantly detected by light receiving means 16. Thus, when the liquid 2 leaks on the floor surface 1, the liquid 2 permeates sequentially from the contact portion 9 into the reflection area 8b of the thin paper 8, and the contact portion 9 of the thin paper 8 turns white due to the permeation of the liquid. Change to transparent color. However, since the reflection plate 4a on the lower side of the thin paper 8 is black, the color of the thin paper 8 changes from white to black at the contact part 9, and the reflected light 24 to the light receiving means 16 is absorbed by the reflection plate 4a and greatly reduced. The change in the amount of reflected light is detected by the detecting means 18 to detect liquid leakage. The liquid leak sensor using such thin paper has a simple structure,
The operation is also reliable, the holder is fixed to the floor with a stopper, etc., so there is no accident that the sensor falls, and there is an advantage that it is possible to detect even a highly viscous liquid in a relatively short time. A user who wants to minimize the installation work and the replacement work of the thin paper as much as possible has demanded a liquid leakage sensor that does not use the thin paper and does not need the work of fixing the holder to the floor surface.

[0003]

As such a liquid leakage sensor that does not use the thin paper 8, there are various types of sensors that irradiate the above-mentioned case bottom portion 12a with totally reflected light and determine the presence or absence of liquid leakage based on the magnitude of the reflected light amount. Although it has been devised, if the bottom of the case is brought into close contact with the floor, a liquid having a high viscosity becomes very difficult to penetrate into the center of the bottom of the case. (A) Generally, a liquid leakage sensor using thin paper 8 Has a structure in which a gap of at least d = 2 to 4 mm is provided between the floor surface and the case bottom so that a large amount of liquid leaks out and the case bottom does not contact the liquid leak. The structure was such that liquid leakage could not be detected at all. (B) In the case of a structure in which the bottom of the case has no holder or cap and is directly exposed to the floor surface, the case is easily affected by the paint color of the floor surface, and is not suitable at the stage when the liquid leaks in. There is also a problem that the determination of the presence or absence of liquid leakage is not stable only by the magnitude of the amount of reflected light, for example, a large amount of required reflected light from the floor surface is received and malfunctions occur. In addition, the conventional optical leak sensor also has the following problems that could not be expected at first. (C) With the holder bottom surface 4a being horizontal on the floor surface 1 and the case bottom portion 12a being installed in a substantially horizontal state, the high-pressure pipes and large-diameter pipes are damaged, and a large amount of liquid is generated / outflow at one time. In this case, the lower part of the case 12 is submerged in the liquid leakage almost all around. In such a state, the leaked liquid 2 is gradually
When the gas begins to permeate from the outer edge of the case toward the inside, the gas in the gap 10 between the holder bottom surface 4a and the case bottom 12a is partially foamed and discharged to the outside of the case 12, The gas in the vicinity of the center of 10 is in a state where its surroundings are blocked by liquid leakage, and as shown in FIG. 1 (B), the bubbles stay in the central portion 8b which is also a reflection region, Even after many hours, the reflection area 8b did not become transparent and a large amount of liquid leakage could not be detected. (D) However, the holder bottom surface 4a is horizontal and flat.
Is currently being used in large quantities, so replacing the holders 4 fixed to the floor 1 one by one takes an enormous amount of time,
Almost impossible. (E) The thin paper 8 is also a consumable item and is discarded every time a liquid leak is detected. However, if possible, it is preferable that the conventional thin paper 8 can be used as it is. (F) Further, the applicant of the present application has proposed in Japanese Patent Application No. 10-353003 a liquid leakage sensor having a structure in which a groove with a slight inclination angle is provided at the bottom of the case. In some cases, the leaked liquid may penetrate into the inside first, blocking the air outlet of the air bubbles as in the conventional case, and it has been found that the structure in which the groove is formed has an insufficient or unstable air air discharging effect. Therefore, the present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a method for generating bubbles and the like at the bottom of a case due to contact with the liquid even when a large amount of liquid leaks at once. It is an object of the present invention to provide a liquid leakage sensor capable of minimizing the influence of the liquid leakage and detecting the liquid leakage stably and reliably. It is also an object of the present invention to use volatile and flammable liquids with
Another object of the present invention is to provide a liquid leakage sensor capable of minimizing the influence of bubbles and the like even if a large amount of such liquid is generated at one time, and capable of detecting liquid leakage safely and reliably in a remote place.

[0004]

According to the present invention, there is provided at least one reflecting boundary surface which can come into contact with a leak through a gas layer or a leak permeable layer through which the leak can penetrate, light source means and light receiving means. The object of the present invention is to project light from the light source means to the reflective boundary surface, receive the reflected light from the boundary surface by the light receiving means, and calculate the output thereof. Along with determining the presence or absence of liquid leakage, bubbles generated in the gas layer or in the liquid leakage permeable layer by the liquid leakage, the suction port is opened in the gas layer or the liquid leakage permeable layer, and the discharge port is opened. This is achieved by discharging to the outside by means of a hollow member that is open to the outside at a height equal to or higher than the predetermined height of the liquid leakage sensor. Further, the present invention forms at least two total reflection boundary surfaces that can come into contact with the liquid leakage and a third reflection boundary surface other than these, with a gas layer or a liquid leakage permeable layer interposed therebetween, and A light source sensor and a light receiving means disposed on the same side with respect to each of the reflection boundary surfaces, and the first total reflection boundary surface is separated from the first light source means. Projecting light, projecting reflected light from the first total reflection boundary surface onto the second total reflection boundary surface, and reflecting light from the second total reflection boundary surface with the first light receiving means. A first detecting means for receiving the light, calculating the output of the light, and detecting the liquid leakage to form a first liquid leakage sensor;
The light is projected from the second light source means at an incident angle smaller than the critical angle with respect to the reflection boundary surface, and the reflected light from the third reflection boundary surface is received by the second light receiving means. It is also achieved by forming a second leak sensor with the second detecting means for detecting the leak by performing arithmetic processing.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 corresponding to FIG. 1 is a hollow member 6a-6 for discharging air bubbles according to the present invention.
d is an example of a liquid leakage sensor 20a provided with the same number, the devices having the same numbers perform the same function, and the liquid leakage from the light source means 14a via the transparent or semi-transparent material 12d at the bottom of the case. A one-dimensional or two-dimensional photoelectric conversion element array in which a plurality of CCDs, MOS-type photodiodes, and the like are illuminated with light 22x at an incident angle equal to or greater than the critical angle with respect to a reflective boundary surface 12a contacting the light. Sensor (hereinafter abbreviated as array sensor) 28A (each light receiving element
a to 28n), the reflected light is received by each light receiving element at a different light receiving angle from each other, converted into an electric signal, and the output is output by the A / D conversion means 32 at each predetermined sampling period. The double buffer memory 3 in the control means 30 which is converted into a digital signal and includes a microprocessor (MPU) 36 and also serves as the detection means 18
4 are sequentially written. Further, the light source means 14b forms a second reflection boundary surface 7 in which the surface of the reflection member 3 made of glass or synthetic resin is adhered to the bottom surface 4a of the holder 4 by an adhesion means 3a such as a double-sided tape. On the other hand, the light 22y is irradiated at an incident angle less than the critical angle, and the reflected light 24y is received by the light receiving means 16b or 28B,
The signal is converted into an electric signal and input to the control means 30. Further, a light shielding member 15 such as a metal foil is adhered to the inside of the case bottom 12a, and one end of the light shielding member 15 is input to the capacitance sensor 39. Has become. Since the light shielding member 15 is disposed in a range excluding the light irradiation surface of the case bottom portion 12a and the reflected light receiving surface near the light receiving means, unnecessary reflected light even if the floor surface is white or a mirror surface at the time of liquid leakage. Is not received from the floor. A fall / inclination sensor 38 is provided in the case 12, and its output is input to the control means 30, and the detection output of the liquid leakage is output as an electric signal 26 to the outside, and further provided on the upper surface of the case 12. The warning means is also displayed on the display means 29 by an LED or the like which can be switched between green and red. The floor 1 of the holder 4
It is preferable to use a contact surface whose outer diameter is 1.3 times or more the outer diameter of the case 12 from the viewpoint of preventing the sensor 20a from tipping over. Further, it is preferable that the distance d between the contact surface 12a of the bottom of the case 12 and the upper surface 4a of the holder 4 can be changed to various ones according to the viscosity of the liquid to be detected. When the angle or interval between the reflection boundary surface 4a and the light receiving unit 28B changes due to, for example,
The holder 4 and the case 12
It is preferable to use a structure that is detachable and that the distance d does not change even with external vibration. Further, when the holder 4 is formed of a light-shielding member, there is an effect of preventing noise light from entering around the case 12 and receiving unnecessary reflected light from the floor surface. When the case 12 is used alone as a liquid leakage sensor without using the holder 4, the above-described distance d is used.
7 so as not to change even with external vibration.
As shown in the figure, the light source means 14 and the light receiving means 16 / 28B
Is housed and integrated in a case 12 whose bottom is made of a transparent or translucent material, and a light-shielding thin plate-like case cap 12h is attached to the end of the case, and the floor surface 1 It is preferable to use a structure that is hardly affected by the surface properties or surface color of the installation location.

Accordingly, the hollow members 6a to 6d for discharging air bubbles are provided.
3 is described with reference to FIG. 3. In this example, all the hollow members 6 are embedded or attached to the member on the holder 4 side of the case 12, and the air inlets 5a to 5d for bubbles are provided.
3B is embedded or attached to the member on the holder 4 side as shown in FIG. 3 (B), and one end of the hollow member 6a avoids the optical path of the projection light 22 and the reflection light 24 and is substantially at the center of the bottom surface 12a of the case 12. The air inlet 5a is opened at the bottom of the case 12a.
Through a hollow pipe member 6a1 made of rubber or synthetic resin, etc., or a hollow portion 6a1 formed in a substantially rectangular parallelepiped case receiving portion provided on the upper surface of the holder 4 so as to protrude in the center direction. And the cavity 6 embedded in the side wall of the holder 4
a2, the other end of the cavity 6a2 is connected to a discharge port 7a formed in the side wall of the holder 4 so that the outlet is formed in a horizontal or downward direction. Therefore, the suction port 5
a through the hollow portion 6a1 and the hollow portion 6a2 to the outlet 7a
It has a hollow structure in which gas can freely enter and leave without leaking to the outside in a state where the surroundings are sealed. In the example of FIG. 3, other similar hollow members 6b to 6d are provided with the suction port 5b.
5d, horizontal hollow portions 6b1 to 6d1, hollow portions (vertical hollow portions) 6b2 to 6d2, and outlets 7b to 7d, but such a hollow member for discharging air bubbles is used alone. Also, a plurality can be used. It should be noted that the height of the outlets 7a to 7d from the floor is such that even if a large amount of liquid is leaked at a time, sufficient time for the bubbles to be discharged to the outside can be secured. It is preferable that the predetermined height position is appropriately high so as not to be submerged.

FIGS. 4 to 6 correspond to FIG.
3 shows another embodiment of the bubble discharging hollow members 6a to 6d according to the present invention. The devices having the same numbers perform the same functions, and all of the hollow members 6a to 6d in the configuration example of FIG. 6d is arranged on the holder 4 side, so the case 1
Although no physical modification is required on the second side and the conventional liquid leakage detection unit 12 can be used as it is, in the example of FIG. 4, the holder 4 is not used and the thin paper 8 is used. This is an example of a liquid leakage sensor that does not include an example of the arrangement of the hollow members 6a to 6d when only the case 12 is used alone. In this case, the hollow members 6a to 6d
The hollow member is liable to be damaged if it goes out of the case or has a protruding part. Therefore, holes 5a to 5d for sucking air bubbles are formed at substantially the center of the case bottom 12a in contact with the gas layer or the liquid leakage permeable layer in FIG.
(B), and discharge ports 7a to 7d are formed in the upper part of the side wall of the case 12, and these are connected by small-diameter hollow members 6a to 6d such as silicone rubber members. It was done. FIG. 5 shows the above-described hollow member formed by using both members of the case 12 and the holder 4. FIG. 5B shows the upper surface of the holder 4 with the case 12 removed. The upper surfaces of the grooves 6a1 to 6d1 provided in the substantially rectangular parallelepiped protrusions for discharging bubbles from the outer side wall of the holder 4 to the substantially center thereof are in close contact with the case bottom portion 12a to form a hollow portion. It is processed horizontally and in a planar shape so that the liquid does not penetrate from the surface. Further, the position of the bubble inlets 5a to 5d in each groove is preferably as central as possible as far as possible without interfering with the optical path of the projected light / reflected light. The other end of each of the horizontal grooves 6a1 to 6d1 is connected to a groove in which the inner wall of the holder 4 is cut to a thickness that allows sufficient movement of the gas. The parts are 6a2 to 6d2 shown in FIG.
After being cut so as to form a groove as described above, the holder 4 is connected to the outside of the case 12 via outlets 7a to 7d provided at a predetermined height of the holder 4. In the hollow member having such a structure as shown in FIG. 5A, hollow members 6a to 6d are formed by the side wall, the inner wall, and a part of the bottom surface of the holder 4 and the part of the side wall and the bottom surface of the case 12. Are provided on the side walls / bottom surface of the holder 4 as shown in FIG.
It is easier to process the grooves 6a to 6d than to form d. It should be noted that the outlets 7a to 7
If d is installed with the upper part opened, if a large amount of liquid leaks out, the liquid outlets 7a to 7d may be blocked by the liquid leakage from above and gas may not be able to move. It is preferable to dispose the portion in a horizontal or downward direction, and when the outlet is opened upward, it is preferable to attach a lid to the upper portion.
Next, FIG. 6 corresponding to FIG. 3 shows another embodiment of the present invention. In this embodiment, the conventional case 12 and holder 4 are used as they are, and a small-diameter hollow member such as a silicone rubber member is used. 6a to 6d are directly adhered to the case bottom 12a and the side wall of the holder 4 with a double-sided tape or the like, and the outlets 7a to 7d are bent horizontally or downward so as to prevent infiltration of the liquid so as to be fixed. Has become.

The operation of the above configuration will be described below. First, when the inclination sensor 38 detects an inclination equal to or more than a predetermined angle, an alarm signal is output to the outside via the control means 30. In a normal state where such an alarm signal is not output, when the liquid leakage 2 does not exist, As shown in FIG. 2B, the projection light 22y from the light source means 14b is reflected by the reflection boundary surface 7 of the reflection member 3 mounted on the holder bottom surface 4a, and the reflection light 24y is received by the array sensor 28B. The light / dark patterns input to the elements 28a to 28n form a light / dark pattern distribution in which the light receiving element 28n is bright and the light receiving element 28a is dark, as shown in FIG. 2C, for example. Further, when the leaked liquid 2 permeates the holder bottom surface 4a thinly, the reflected light 24y enters each light receiving element via an optical path like 24a in FIG. The light and dark pattern is shifted in the brightness peak. When the thickness (depth) of the liquid leakage further increases, the peak of the light and dark pattern moves to the left side of FIG.
When a large amount of the liquid 2 is generated at one time, the entire outer periphery of the case 12 is flooded with the liquid 2.
The hollow members 6a to 6d are buried or attached to the sides, so that when the leaked liquid 2 gradually penetrates from the outer periphery of the case 12 toward the center by capillary action or osmotic pressure, the holder bottom surface 4a The gas in the gap 10 with the case bottom 12a is in a state where its surroundings are closed by liquid leakage, but bubbles generated / remaining on the case bottom 12a from the bubble inlets 5a to 5d are hollow pipes. A discharge port which is gradually extruded into the members 6a1 to 6d1 and further has an outlet formed in the side wall of the holder 4 through the hollow portions 6a2 to 6d2 buried in the side wall of the holder 4 so as to be directed horizontally or downward. Air bubbles generated on the case bottom surface 12a from 7a to 7d are discharged to the outside of the case 12. That is, since the hollow members 6a to 6d have a structure in which gas can freely enter and leave without leaking to the outside in a state where the surroundings are sealed, the case bottom portion 12a
Even if bubbles are generated, the gap 10 between the holder bottom surface 4a and the case bottom portion 12a can be filled with the liquid leak 2 and immersed in water very quickly without staying for a long time. Thus, when the case bottom 12a is submerged in the liquid 2, the reflected light 24m is, for example, received by the light receiving element 28 shown in FIG.
The arrangement changes to an arrangement of a bright and dark pattern on the side a, which is the brightest, and on the side of the light receiving element 28n, the darkest.

Therefore, after writing the digital output after the A / D conversion of each of the light receiving elements 28a to 28n of the array sensor 28B into the double buffer memory 34 at a predetermined sampling cycle, the following processing is preferably performed by the MPU or the like. . a) After the sensitivity of each light receiving element 28i (i = a to n) is corrected, the light receiving pattern is smoothed by moving average processing or the like. b1) The peak position of lightness and darkness of the smoothed light receiving pattern is calculated, and the presence or absence of liquid leakage is determined based on whether or not this position is within the range without liquid leakage. b2) The center of gravity XG of the luminance distribution of the amount of reflected light of the smoothed light receiving pattern R (j) is calculated by the following equation, and the presence or absence of liquid leakage is determined based on whether or not the position of the center of gravity is within the range without liquid leakage.

XG = ΣR (j) · j / Σj (j = 1 to n) where R (j): light receiving level j =: light receiving position b3) The rising edge of the waveform of the bright and dark pattern of the reflected light and / or Alternatively, a waveform peak portion and / or a waveform falling portion are cut out from a reflected light pattern having a leak and the leaked template pattern T (j) is stored in a template memory or the like.
And register this template pattern T
Light receiving pattern R obtained by smoothing a waveform position similar to that of (j)
The calculation is performed by the following equation in (j).

(Equation 2) Next, at a position (m> mth) that is at least a predetermined distance (mth) from the no-leakage position and at a predetermined similarity Thcr
Light / dark pattern CR similar to the above template waveform
If (m) is detected, it is determined that there is liquid leakage, and otherwise, it is determined that there is no liquid leakage. c) Thus, the control means 30 also serving as the liquid leakage detecting means 18
Accordingly, when the leaked liquid 2 is detected by a desired operation or a combined operation among the operations from b1) to b3), the display means 29 is turned on in red and the presence or absence of the liquid leakage to the outside via the cable 26 is determined. Output. Note that b1) and b
In the process (2), the reflected light is widely collected by the condensing means such as a lens, so that the presence / absence calculation of the liquid leakage can be executed by at least two light receiving means (elements). In the correlation calculation of b3), it is preferable to collect reflected light data from the light receiving unit (element) from at least 4 to 8 different positions. Also, the projection light 22x from the light source means 14a is
2a, the reflected light 24x is reflected by the array sensor 2
The light receiving elements 28a to 28n of 8A are inputted in the same manner as the above-described array sensor 28B, and the distribution, position, and the like of the light and dark patterns are controlled by the control means 30 which also serves as the liquid leakage detecting means 18.
The calculation is performed in the same manner as described above, and the presence or absence of liquid leakage is determined.
The control means 30 checks both outputs of the array sensors 28B / 28A at predetermined intervals, and outputs a liquid leak detection signal to the outside if a liquid leak is detected based on either output calculation result. Good to do. Also, in the above example,
Since the reflected light 24x is totally reflected light, the array sensor 2
Instead of 8A, even if the presence or absence of liquid leakage is determined from the magnitude of the amount of reflected light from the output of the single light receiving element 16, it is possible to easily determine the detection of liquid leakage.

Therefore, according to the liquid leakage sensor having the structure as shown in FIG. 2, the liquid leakage sensor 20a is simply placed on the floor surface 1 without using the thin paper 8, and the sensor is simply fixed to the floor surface.
Even if a large amount of liquid leakage does not flow out, it is possible to reliably detect the liquid leakage at the initial point when the liquid leakage 2 has slightly penetrated the reflective boundary surface 4a of the holder 4, and to increase the radius of the outer periphery of the holder 4. By doing so, it is possible to prevent the sensor 20a from falling down. Also, as shown in FIG.
y are projected in directions orthogonal to each other, so that mutual optical interference is small. However, the light source means 14a / 14b are alternately turned on by control means (not shown), and the light source means 14a
Is turned on, the light source means 14b is turned off, and the light source means 14a
When the light source means 14b is turned on while the light is off,
Interference between light sources can be completely eliminated. In the above-described example, the projection light 22y from the light source means 14b is reflected by the reflection boundary surface 7 of the reflection member 3 placed on the holder bottom surface 4a, but the reflection member 3 is not used and the holder bottom surface 4a is directly used.
Is received by painting the holder bottom surface 4a with a gray intermediate color or white, and the like, and receiving the reflected light 24y
May be input to the array sensor 28B. Also, thin paper 8
Can be used in place of the reflecting member 3. In this case, the distance d between the case bottom 12a and the holder bottom 4a can be set to 1 mm or less, and when the thin paper 8 is used. Is necessary to replace the thin paper after detecting liquid leakage. However, if the reflecting member 3 is used, if the liquid 2 is wiped off from the reflecting member 3 with a dry cloth or the like, the same reflecting member can be repeatedly used. is there. Thus, even if a large amount of liquid leakage occurs, the hollow members 6a to 6d have a structure in which the gas can freely enter and exit from both ends without leaking to the outside in a state where the surroundings are sealed. Even if air bubbles are generated, the gap 10 between the holder bottom surface 4a and the case bottom 12a can be filled with the liquid leakage 2 very quickly without staying for a long time, and the gap 10 can be reliably submerged. In addition, it is possible to prevent malfunction of the liquid leakage sensor due to generation of bubbles. In the above example, two optical systems are used. However, even if only one of the optical systems of the light source unit 14a to the light receiving unit 28A or the light source unit 14b to the light receiving unit 28B is used, the liquid leakage sensor 20a can be configured. can do.

Next, FIG. 7 corresponding to FIG. 2 and FIG.
Shows another embodiment of the liquid leakage sensor 20b according to the present invention. The devices having the same reference numerals perform the same function, and eliminate the electric wiring in the liquid leakage detecting portion, thereby making the electric ignition / It is designed to prevent a fire accident from occurring, and by means of optical transmission means 40a and 40b such as optical fibers.
The projection light 22x, 22y is transmitted from the light source means 14 provided in the remote control unit 31, and the light transmission means 40a, 42a
To 42k to form a first optical system for projecting and receiving light to the reflection boundary surface 12a, and the optical transmission means 40b, 42m to
Since the second optical system for projecting and receiving light on the reflective boundary surface 7, the thin paper 8, the case cap 12h, and the like is formed by the 42t, the liquid 2 is extremely volatile even if there is a danger of ignition or explosion. The leak detection by reflected light can be performed safely. That is, in the above-mentioned first optical system, a part of the irradiation light from the light source means 14 provided at a remote place is guided into the case 12 by the light transmission means 40a, and the angle is equal to or larger than the critical angle such that total reflection occurs. The light is radiated at a predetermined angle to the reflective boundary surface 12a at the bottom of the case as the projection light 22x, and the reflected light 24x is received by the linearly arranged light transmission means 42a to 42k, and the array sensor 28A provided at a remote place. Are transmitted to the light receiving elements 28a to 28k, and are input to the control means 30 also serving as the detection means via the AD conversion means 32 and the double buffer 34. Further, in the second optical system described above, another part of the irradiation light from the light source unit 14 provided at a remote place is guided into the case 12 by the light transmission unit 40b, and is formed at a predetermined angle within the critical angle. The reflection boundary surface 7, or the thin paper 8, not shown, or the case cap 12h is irradiated as the projection light 22y, and the reflection light 24y is received by the linearly arranged light transmission means 42m to 42t and provided at a remote place. The light is transmitted to the light receiving elements 28m to 28t of the array sensor 28B and input to the control means 30 which also serves as the detection means via the switch means, the AD conversion means 32, and the double buffer 34. Further, in order to prevent bubbles from being generated and staying in the void portion 10 for a long period of time, all the hollow members 6a to 6d are disposed inside the case 12 without using the holder 4 as in the structure of FIG. A bubble discharging mechanism is provided, and holes 5a to 5d for sucking bubbles are formed in a substantially central portion of the case bottom portion 12a in contact with the gas layer or the liquid leakage permeable layer in FIG.
(B) and as shown in FIG. 7, and discharge ports 7a to 7d are formed in the upper part of the side wall of the case 12, and these are connected by small-diameter hollow members 6a to 6d such as silicone rubber members. It has a structure. In addition, the bottom of the case 12 is formed by using a transmitted light member 12d made of a transparent material or a translucent material as a base material. It is preferable to cover or configure with the member 12g and integrally mold it with the transmitted light member 12d. If such a light shielding member is used, even if the holder 4 is not provided, it is affected by ambient noise light or the floor surface becomes white when liquid leaks. Alternatively, it is possible to realize an optical structure in which unnecessary reflected light is not received from the floor surface even with a mirror surface. In the example of FIG. 7,
Light-shielding case cap 1 painted in neutral or white
2h is attached to the tip of the case 12, but the thin paper 8 is placed on this, and nothing is placed on the tip of the case 12, and the reflected light 24y from the floor 1 is directly reflected. It is also possible to perform liquid leakage detection processing by receiving light, similarly to FIG.

The operation of the above configuration will be described below. First, when there is no liquid leak 2, the projection light 22y from the light source means 14 and the light transmission means 40b is transmitted by the second optical system in the same manner as in FIG. 12h etc., are reflected by the reflection boundary surface 7,
The reflected light 24y is transmitted and input to the light receiving elements 28m to 28t of the array sensor 28B in the remote control unit 31 via the light transmitting means 42m to 42t, and the light / dark pattern is, for example, the light receiving element 28t side. A bright and dark pattern distribution is formed that is bright and the light receiving element 28m side is dark. When the leaked liquid 2 permeates the floor 1 thinly, the reflected light 24y is arranged in a light and dark pattern in which the brightness peak is slightly shifted toward the light receiving element 28m. Further, as the thickness (depth) of the liquid leakage increases, the peak shift of the light-dark pattern increases. When a large amount of liquid 2 is generated at one time, the entire outer periphery of the case 12 is flooded with the liquid 2,
Since the hollow members 6a to 6d are buried in the case 12 side, when the leaked liquid 2 gradually permeates from the outer periphery of the case 12 toward the center, a gap between the floor surface 1 and the case bottom 12a is formed. The gas that was in 10 is in a state where its surroundings are blocked by leakage, and the water pressure or osmotic pressure of the leakage causes the bottom 12a of the case to leak.
Are extruded into the hollow members 6a to 6d from the air bubble inlets 5a to 5d, and further discharged to the outside of the case 12 from the outlets 7a to 7d formed in the side wall of the case 12. That is, since the hollow members 6a to 6d have a structure in which gas can freely enter and leave without leaking to the outside in a state where the surroundings are sealed, even if air bubbles are generated in the case bottom portion 12a, they remain for a long time. In addition, the gap 10 between the floor surface 1 and the case bottom 12a can be filled with liquid leakage very quickly and submerged. Thus, when the case 12 is submerged in the leaked liquid 2, the reflected light 24y is transmitted to the light receiving element 28, for example.
The arrangement on the m side is the brightest and the arrangement on the light receiving element 28t side is the darkest light and dark pattern. Therefore, each of the light receiving elements 28m to 28t of the array sensor 28B has a predetermined sampling period.
Is written to the double buffer memory 34,
U and the like, the same processing as in FIG. 2 is performed, a plurality of light receiving means are arranged so that the light receiving angles are different from each other, and the plurality of light receiving means are used so that the light receiving positions of the reflected light can be distinguished from each other. It converts the output of these light receiving means into a signal, determines the arrangement of the light and dark pattern of the reflected light at predetermined intervals, and determines the arrangement of the light and dark pattern of the reflected light or the position of the light and dark pattern of the reflected light. The presence or absence of liquid leakage may be determined, or the output of the light receiving means may be subjected to arithmetic processing to detect the presence or absence of liquid leakage based on the amount of reflected light. Further, when a large amount of liquid leakage 2 occurs at once, the projection light 22x from the light source means 14 and the light transmission means 40a constituting the first optical system is transmitted to the case bottom 1
Since the light is not totally reflected by 2a and is substantially straight into the liquid having substantially the same refractive index and is dispersed in the gap 10, the reflected light 24x is dispersed and the light receiving element (means) such as an array sensor is provided. And the distribution pattern of the reflected light also fluctuates greatly. Therefore, each of the array sensors 28A provided in the remote controller 31 via the optical transmission means 42a to 42k. Light receiving elements 28a-2
If the reflected light is input to 8k and processed in the same manner as in the above-described array sensor 28B, the distribution and position of the light and dark pattern or the amount of reflected light greatly fluctuates. These changes can be detected by the control means 30 in the same manner as described above, and the presence or absence of a large amount of liquid leakage can be easily determined.

Therefore, according to the liquid leakage sensor 20b having a structure as shown in FIG. 7, the liquid leakage sensor 20b is placed on the floor surface 1 and is hardly affected by extraneous light even without the holder 4 or the thin paper 8. In addition, there is an advantage that the leaked liquid 2 can be detected quickly in the initial stage of the leaked outflow in which the leaked liquid 2 does not flow out to the total reflection boundary surface 12a in a large amount. In addition, since no electric signal flows to the liquid leakage detection unit, it is possible to detect the volatile liquid extremely safely even if a large amount of liquid leaks at once. Is double-checked and detected, the reliability of the liquid leakage detection process can be further improved, and the light source means 14 and the light-receiving means 28A can be changed by changing the length of the light transmission means 40/42. / 28B
, And the physical distance to the reflection boundary surface 12a / 7 or the like can be changed to a desired variable distance. Further, it is apparent that the case head portion in which the light shielding member 12g and the transmitted light member 12d are integrally formed can be applied to the liquid leakage sensor without the thin paper 8 shown in FIGS. When the light-shielding case cap 12h is attached to the tip of the case 12, there is an advantage that the influence of the surface properties of the floor 1 on which the sensor 20b is installed, the floor coating color, and the like can be eliminated. FIG.
As shown in (B), since the projection lights 22x and 22y are projected in directions orthogonal to each other, there is little mutual optical interference, but the light source means 14 is turned on alternately in time,
The projection light is intermittently output by shutter means or the like (not shown) to the light transmission means 40a and 40b, and the light transmission means 4
0a / 40b is turned on, the light transmission means 40b is turned off while the light transmission means 40a is turned on, and the light transmission means 40b is turned on while the light transmission means 40a is turned off. Can be completely eliminated. When the thin paper 8 is used, the distance d between the case bottom portion 12a and the floor surface 1 can be sufficiently reduced to 1 mm or less. In such a case, even if a large amount of liquid leakage occurs, the hollow member 6
Since a to 6d have a structure in which gas can freely enter and leave without leaking to the outside in a sealed state, even if bubbles are generated in the case bottom portion 12a, they do not stay for a long time, The gap 10 between the floor surface 1 and the case bottom 12a can be quickly filled with the liquid leakage 2 while preventing bubbles from stagnating, and can be reliably submerged. In the above example, two optical systems are used. However, even if only one of the optical systems of the light source unit 14a to the light receiving unit 28A or the light source unit 14b to the light receiving unit 28B is used, the liquid leakage sensor 20b
Can be configured.

Next, FIG. 8 corresponding to FIGS. 2, 5 and 7 shows another embodiment of the liquid leakage sensor 20c of the present invention. The device performs the same function, and is mounted on the bottom 12a of the case 12 made of a transparent or translucent member as shown in FIG.
(A) and (B), a protruding liquid leak detecting portion is provided protrudingly, and this detecting portion is provided with planar total reflection surfaces 12m and 12n at an inclination angle of approximately 45 degrees. These planar total reflection surfaces 12m and 12n are formed so that their extensions intersect with each other in a substantially orthogonal state so that the tips thereof perform the same function as a corner cube, and form the first optical system. Projection light 22u from the light source means 14a to be formed irradiates the total reflection surface 12m downward from substantially vertically above, and the reflection light 22v is projected on the total reflection surface 12n to form the total reflection surface 12n.
Is received by the light receiving means 16 and is converted into an electric signal. The irradiation position of the projection light 22u on the total reflection surface 12m is preferably a lower position as close to the floor 1 as possible. Further, the whole case 12 is inserted / attached to and fixed to the holder 4, and the holder 4 may be fixed to the floor surface 1 by a fixing member such as a nail, or may be simply fixed to the floor surface without fixing. It is also possible to simply place it movably on 1. Further, similarly to FIG. 5, the hollow member 6a
6D are formed on the outer periphery of the case 12 and the bottom and the inner side surface of the holder 4, and FIG. 8C shows a top view of the holder 4. In the case where thin paper 8 is used, the holder reflective surface 4r is painted black to absorb the reflected light, and the case bottom end 12a is formed. Gap distance d between the holder and the reflecting surface 4r
Is preferably 1 mm or less. On the other hand, when the thin paper 8 is not used, the reflected light from the holder reflecting surface 4r and the reflected light from the floor 1 are processed directly. It is painted in white or neutral color that reflects light, and the case bottom end 12a and the holder reflection surface 4 are coated.
It is preferable that the gap d be 2 mm or more apart from the gap layer r so that a liquid having a high viscosity can easily penetrate. Further FIG.
In (2), the end portions of the above-mentioned planar total reflection surfaces 12m and 12n are cut into a flat shape, and the cut
A second optical system is formed via the light source means 14b.
When the incident light 22y from the
From the thin paper 8, the holder reflection surface 4r, the floor surface 1 or the like.
b or the array sensor 28B receives light and converts it into an electric signal. When a light-shielding member 15 such as a metal foil is adhered to the inside of the case bottom 12a and one end of the light-shielding member 15 is input to the capacitance sensor 39, the light-shielding member 15 reflects the light near the light irradiation surface and the light receiving means. It can be arranged in a range excluding the light receiving surface, and has an optical effect of preventing unnecessary reflected light from being received from the floor surface even when the floor surface is white or a mirror surface when liquid leaks.

The operation of the liquid leakage sensor 20c in such a configuration will be described. When the inclination sensor 38 detects an inclination greater than a predetermined angle, an alarm signal is output to the outside. The output of the means 16, the array sensor 28B, and the output of the capacitance sensor 39 are checked. When the leakage of the leakage is small, the leakage detection processing is executed mainly by the second optical system, and the projection is performed. The reflected light 24y from the thin paper 8 or the holder reflecting surface 4r or the reflecting boundary surface such as the floor 1 corresponding to the light 22y is received by the sensor 28B and its output is processed to reduce the reflected light or to reduce the reflected light. If the position of the light and dark pattern changes or the output of the capacitance sensor 39 changes beyond a predetermined range, the liquid 2 may leak to the thin paper 8 or the holder reflection surface 4r. Is determined to have approached to the reflecting boundary surface or case bottom 12d such floor 1, and outputs a leak detection signal to the outside. Further, when a large amount of the liquid leakage 2 flows out to the floor 1 or the like at a time, the liquid leakage detection processing is mainly performed by the first optical system, and even if the brightness of the projection light 22u is constant, the total reflection surface 12m, The reflected light 22v, 24u from 12n is leaked liquid 2
Since the light is dispersed to the side and greatly reduced, the output of the light receiving means 16 also changes greatly, and a liquid leakage detection process with further improved reliability can be easily realized. Therefore, even if bubbles are generated for a long time on the case bottom surface 12a constituting a part of the above-mentioned second optical system, the first optical system is not affected by such bubbles, and the first optical system executes a stable liquid leakage detection process. it can. If a bubble discharge mechanism similar to that shown in FIGS. 3 to 6 is provided around the case and / or the holder, bubbles can be prevented from generating and staying in the gap 10 for a long time, and malfunction due to reflected light bubbles can be prevented. And the reliability and stability of the operation of the liquid leakage sensor can be further improved. Also, the projection / reception optical system of the liquid leakage sensor of FIG. 8 is replaced with a projection light / reception optical system as shown in FIG. 7 to constitute a leakage detection unit for volatile / flammable leakage, and the electric wiring is changed. It is also possible to make modifications so that an electrical fire / ignition accident will never occur, and provided in the remote control unit 31 by optical transmission means 40a and 40b such as optical fibers in the same manner as in FIG. The projection light 22x, 22y is transmitted from the light source 14 thus provided, and the light transmission means 40a,
A first optical system for projecting and receiving light on the reflection boundary surface 12a is formed by the light transmission means 40b,
By forming a second optical system for projecting and receiving light on the reflective boundary surface 7, the thin paper 8, the case cap 12h, and the like by 2m to 42t, the liquid 2 is volatile and is extremely safe even when there is a danger of ignition or explosion. Liquid leak detection can be performed by reflected light.

[0016]

As described above, according to the optical liquid leakage sensor of the present invention, since a hollow member realizes a bubble discharging mechanism utilizing the water pressure / osmotic pressure of the liquid leakage, a large amount of liquid leakage is detected. Is generated, the gas can freely enter and exit from both ends of the hollow members 6a to 6d without leaking to the outside in a state where the surroundings are sealed.
Even if bubbles are generated in a, the gap 10 formed between the holder bottom surface 4a and the case bottom 12a is filled with the liquid leakage 2 very quickly without staying for a long time.
0 can be reliably submerged, and malfunction of the liquid leakage sensor due to generation of bubbles can be prevented. Normally, even if the leak sensor is simply placed on the floor 1 and a large amount of the leak does not flow out, the leak 2 is slightly absorbed into the reflection boundary surface 4a of the holder 4, the floor 1 and the like. At this point, the liquid leakage can be reliably detected, and the fall of the liquid leakage sensor can be prevented by increasing the radius of the outer periphery of the holder 4. In addition, although the example in which the projection light 22y from the light source means 14b is reflected by the reflection boundary surface 7 of the reflection member 3 placed on the holder bottom surface 4a, the reflection member 3 is not used, and the light is directly reflected from the holder bottom surface 4a. The reflected light 24y may be input to the array sensor 28B, or the thin paper 8 may be used instead of the reflecting member 3. In this case, the case bottom 12 a and the holder bottom 4 a
Can be set within 1 mm. When thin paper 8 is used, it is necessary to replace the thin paper after detecting liquid leakage. When the leaked liquid 2 is wiped off from the reflecting member 3, there is a difference that the same reflecting member can be repeatedly used. In the case of a type of liquid leak sensor that does not use thin paper, conventionally, the liquid leaks on the floor surface.
Although leaks could not be detected unless they overflowed to a depth of at least 4 mm and leaked in large quantities, the leak sensor according to the present invention does not leak at the initial point when the leak has penetrated the floor by 0.1 mm or more. Can be sufficiently detected, and a serious liquid leakage accident can be prevented. In addition, if a sensor having no electric wiring is used in the liquid leakage detecting section, a volatile liquid which may cause a fire and explosion can be detected safely and reliably. Furthermore, in the above-described type of liquid leakage sensor using the total reflection boundary surface, the reflection surface inclined at approximately 45 degrees is used. A malfunction of the sensor can be prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing the structure of a conventional optical liquid leak sensor using thin paper.

FIG. 2 is a diagram showing a structure of a liquid leak sensor and a light reflection path of the present invention.

FIG. 3 is a view showing one example of a bubble discharging mechanism of the present invention.

FIG. 4 is a diagram showing an example of a sensor with a built-in air bubble discharge mechanism of the present invention.

FIG. 5 is a view showing another example of the bubble discharging mechanism of the present invention.

FIG. 6 is a view showing another example of the bubble discharging mechanism of the present invention.

FIG. 7 is a diagram showing an example of an explosion-proof liquid leakage sensor of the present invention.

FIG. 8 is a diagram showing an example of another liquid leakage sensor of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Floor surface 2 Liquid leak 3 Reflection member 4 Holder 4a Holder bottom surface 5a-5d Bubble suction port 6a-6d Bubble discharge mechanism / hollow member 7a-7d Bubble discharge port 4a, 7, 12a, 12m, 12n Reflection boundary surface 8 Thin paper 10 Void portion 12 Case 12d Transmitted light member 12g Light shielding member 12h Case cap 14, 14a, 14b Light source means 16, 28A, 28B Light receiving means, array sensor 20a-20c Liquid leak sensor 22, 22a-22y Projection light 24, 24a-24y Reflection Light 30 Control means 32 AD conversion means 34 Double buffer 36 MPU 40, 40a, 40b, 42, 42a, to 42z Light transmission means 38 Inclination sensor 39 Capacitance sensor

Claims (27)

[Claims] 1. A liquid leakage sensor comprising: at least one reflection boundary surface capable of contacting the liquid leakage through a gas layer or a liquid leakage permeable layer through which the liquid leakage can penetrate; and a light source means and a light receiving means. The light is projected from the light source means to the reflective boundary surface, the reflected light from the boundary surface is received by the light receiving means, and the output thereof is arithmetically processed to determine the presence or absence of liquid leakage, and the gas is generated by the liquid leakage. The air bubbles generated in the layer or the liquid leakage permeable layer are opened at the suction port in the gas layer or the liquid leakage permeable layer, and the discharge port is opened at a height equal to or higher than the predetermined height of the liquid leakage sensor. A liquid leakage sensor characterized in that the liquid is discharged to the outside of the case by a hollow member opened to the case. 2. The light source means and the light receiving means are housed and integrated in a case whose bottom is made of a transparent material or a translucent material, or the light source means and the light receiving means are made of a transparent material or a translucent material at the bottom. Along with being housed and integrated in the configured case, a light-shielding thin plate-shaped case cap is attached to the end of the case,
It is hardly affected by the surface properties or surface color of the installation location such as the floor of the liquid leakage sensor, or the light source unit and the light receiving unit are housed in a case whose bottom is made of a transparent or translucent material and integrated. At the same time, a case holder is provided at the end of the case, which is hardly affected by the surface properties or surface color of the installation location such as the floor of the liquid leakage sensor, and which also prevents the case from tipping over. The liquid leakage sensor according to claim 1. 3. A first optical transmission unit is interposed between the light source unit and the reflection boundary surface, and a second optical transmission unit is interposed between the reflection boundary surface and the light reception unit. Insert,
3. The liquid leakage sensor according to claim 1, wherein a physical distance between the light source unit and the light receiving unit and the reflection boundary surface can be changed to a variable distance. 4. The liquid leakage sensor according to claim 3, wherein said optical transmission means is an optical fiber or a synthetic resin member. 5. At least two reflection boundary surfaces which can come into contact with the liquid leakage are formed with a gas layer or a liquid leakage permeation layer interposed in the light traveling direction, and at least two light source means and light receiving means are provided for each of said reflection means. Each of the boundary surfaces is disposed on the same side, and light is projected from the first light source unit to a first reflection boundary surface closest to the light source unit, and light is projected from the first boundary surface. The first light receiving means receives the reflected light, and the output of the first light receiving means is subjected to arithmetic processing to constitute a first liquid leak sensor. Light is projected from the second light source means to the boundary surface at an incident angle smaller than the critical angle, and
The second light-receiving sensor is configured to receive reflected light from a reflection boundary surface other than the boundary surface with the second light-receiving unit, and to calculate the output of the second light-receiving unit to detect liquid leakage. Along with the bubbles generated in the gas layer or the liquid leakage permeable layer by the liquid leakage, the suction port is opened to the bubble side, and the discharge port is at a height equal to or higher than a predetermined height of the liquid leakage sensor. A liquid leakage sensor wherein the liquid is discharged to the outside of the case by a hollow member opened to the outside. 6. The first light source means and the second light source means are the same light source means, and split light projected from the light source means by a spectral means, and project light from different projection positions. 6. The liquid leakage sensor according to claim 5, wherein: 7. The light source means and the light receiving means are housed and integrated in a case whose bottom is made of a transparent material or a translucent material, or the bottom of the light source means and the light receiving means is made of a transparent material or a translucent material. Along with being housed and integrated in the configured case, a light-shielding thin plate-shaped case cap is attached to the end of the case,
It is hardly affected by the surface properties or surface color of the installation location such as the floor of the liquid leakage sensor, or the light source unit and the light receiving unit are housed in a case whose bottom is made of a transparent or translucent material and integrated. At the same time, a case holder is provided at the end of the case, which is hardly affected by the surface properties or surface color of the installation location such as the floor of the liquid leakage sensor, and which also prevents the case from tipping over. The liquid leakage sensor according to claim 5. 8. A first light transmission means is interposed between the light source means and the reflection boundary surface, and a second light transmission means is interposed between the reflection boundary surface and the light reception means. Insert,
The liquid leak sensor according to any one of claims 5 to 7, wherein a physical distance between the light source unit and the light receiving unit and the reflection boundary surface can be changed to a variable distance. 9. The liquid leakage sensor according to claim 8, wherein said optical transmission means is an optical fiber or a synthetic resin member. 10. The opening and closing direction of the discharge port is arranged to be horizontal or downward so that the liquid does not flow backward and permeate from the discharge port, or a lid is provided above the discharge port. The liquid leakage sensor according to any one of claims 1 to 9, wherein: 11. The hollow member is constituted only by the case member, is constituted only by a holder member of the case, or is constituted by a combination member of the case member and the holder member. The liquid leakage sensor according to any one of claims 1 to 10, wherein the liquid leakage sensor includes a third member that is different from the case member and the holder member. 12. The case according to claim 1, wherein the reflection boundary surface is the bottom of the case, and / or a case cap attached to a tip of the case, and / or an upper surface of the case holder. 2. The liquid leakage sensor according to item 1. 13. The liquid leakage sensor according to claim 1, wherein thin paper that becomes transparent due to liquid penetration penetrates and is closely attached to at least one of the reflection boundary surfaces. 14. An arithmetic processing of an output of said light receiving means to detect the presence or absence of liquid leakage based on the magnitude of reflected light.
And / or disposing the plurality of light receiving means such that the light receiving angles of the plurality of light receiving elements are different from each other, and converting the light receiving positions of the reflected light into electric signals so that the light receiving positions of the reflected light can be distinguished from each other. The output of the light receiving means is arithmetically processed to determine the arrangement of the light and dark patterns of the reflected light at predetermined intervals, and the presence or absence of liquid leakage is determined based on a change in the light and dark pattern of the reflected light. The liquid leakage sensor according to any one of the above items. 15. The light source means projects modulated light, in which the light / dark pattern of the projected light changes at a predetermined cycle, onto the reflective boundary surface, and receives the reflected light by the light receiving means in synchronization with the timing of the projected light. The liquid leakage sensor according to any one of claims 1 to 14, wherein the liquid leakage sensor is configured to perform the operation. 16. At least two total reflection interfaces capable of contacting a liquid leakage are formed with a gas layer or a liquid leakage permeation layer interposed therebetween, and at least one light source means and a light receiving means are provided for each of the reflection interfaces. And light is projected from the light source means onto the first total reflection boundary surface, and reflected light from the first total reflection boundary surface is reflected on the second total reflection boundary surface. A liquid leakage sensor which projects light onto a reflection boundary surface, receives light reflected from the second total reflection boundary surface by the light receiving means, and processes the output to detect liquid leakage. . 17. At least two total reflection interfaces that can come into contact with the liquid leakage and a third reflection interface other than these are formed with a gas layer or a liquid leakage permeation layer interposed therebetween, and at least 2
Two light source means and a light receiving means are arranged on the same side with respect to each of the reflection boundary surfaces, and project light from the first light source means to the first total reflection boundary surface; The light reflected from the first total reflection boundary is projected onto the second total reflection boundary, the light reflected from the second total reflection boundary is received by the first light receiving means, and the output is received. And a first detecting means for detecting a liquid leak by performing arithmetic processing, wherein a first liquid leak sensor is formed, and an incident angle less than a critical angle with respect to the third reflecting boundary surface is provided from the second light source means. A second light receiving means for projecting light, receiving the reflected light from the third reflecting boundary surface by a second light receiving means, calculating the output thereof, and detecting the liquid leakage; A liquid leakage sensor comprising a sensor. 18. The light source device according to claim 1, wherein the first light source and the second light source are the same light source, and the light emitted from the light source is split by a spectroscope so as to project light from different projection positions. 18. The liquid leakage sensor according to claim 17, wherein: 19. The light source means and the light receiving means are housed and integrated in a case whose bottom is made of a transparent material or a translucent material, or the bottom part of the light source means and the light receiving means is made of a transparent material or a translucent material. Along with being housed and integrated in the configured case, a light-shielding thin plate-shaped case cap is attached to the end of the case,
It is hardly affected by the surface properties or surface color of the installation location such as the floor of the liquid leakage sensor, or the light source unit and the light receiving unit are housed in a case whose bottom is made of a transparent or translucent material and integrated. At the same time, a case holder is provided at the end of the case, which is hardly affected by the surface properties or surface color of the installation location such as the floor of the liquid leakage sensor, and which also prevents the case from tipping over. The liquid leakage sensor according to any one of claims 16 to 18. 20. A first optical transmission means interposed between the light source means and the reflection boundary surface, and a second optical transmission means interposed between the reflection boundary surface and the light receiving means. Insert,
17. The physical distance between the light source unit and the light receiving unit and the reflection boundary surface can be changed to a variable distance.
20. The liquid leakage sensor according to any one of claims 19 to 19. 21. The liquid leakage sensor according to claim 20, wherein the optical transmission means is an optical fiber or a synthetic resin member. 22. A bubble generated in the gas layer or the liquid leakage permeable layer due to the liquid leakage, an inlet opening the gas layer or the liquid leakage permeable layer, and a discharge port opening the liquid leakage sensor. 22. The liquid leakage sensor according to any one of claims 16 to 21, wherein the liquid is discharged to the outside of the case by a hollow member that is open to the outside at a height equal to or higher than a predetermined height. 23. An opening / closing direction of the discharge port is arranged in a horizontal direction or a downward direction so as to prevent the leaked liquid from flowing backward from the discharge port and penetrating therethrough, or a lid is provided above the discharge port. Item 23. The liquid leakage sensor according to item 22. 24. The hollow member is constituted only by the case member, is constituted only by a holder member of the case, or is constituted by a combination member of the case member and the holder member. 24. The liquid leakage sensor according to claim 22 or 23, wherein the liquid sensor comprises a third member different from the case member and the holder member. 25. The case according to claim 16, wherein the reflection boundary surface is the bottom of the case, and / or a case cap attached to a tip of the case, and / or an upper surface of the case holder. 2. The liquid leakage sensor according to item 1. 26. The liquid leakage sensor according to claim 16, wherein thin papers that become transparent due to the penetration of liquid leakage are arranged side by side on at least one of the reflection boundary surfaces and are brought into close contact with each other. 27. The method according to claim 1, wherein thin paper which becomes transparent due to the permeation of the liquid is not juxtaposed in the gas layer or the liquid permeation layer. The liquid leakage sensor as described in the above.