JP2000221100A - Leakage liquid sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To early detect leakage although leak liquid is not contacted with the bottom part of a case and without using thin paper by projecting a ray from a light source to a reflection interface, computation processing output of a reflecting light receiving means to determine arrangement of a contrast pattern at every period, and searching for variation of the arranged position. SOLUTION: In this leakage sensor 20a, thin paper is not used, the bottom surface of a holder 4 is painted in grey color, the reflecting light 24 is input to a photoelecric transfer element array sensor 28 (28a-28n). By reflecting light 24 in the case of no leakage liquid 2, reflecting light 24a when leakage liquid 2 thinly permestes the bottom face 4a, reflecting light 24z when thickness of leak liquid becomes large and a case 12 submerges in the leakage liquid 2, or the like, arrangement of contrast patterns are respectively changes. Consequently, after writing output of the respective elements 28a-28n of the array sensor 28 in a double buffer memory 34 in a fixed sampling period, the peak contrast position of a received light pattern smoothed by an MPU 36 or the like is computed, and by computing the brightness distribution of reflecting light quantity and the position of a center of gravity, existence of leak liquid can be judged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to water, an acidic solution,
The present invention relates to an improvement in a liquid leakage sensor that detects leakage of a liquid having electrical conductivity such as an alkaline solution or a liquid having an insulating property such as organic such as alcohol, thinner, and benzene.

[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. Also, Japanese Patent Publication No. 4-70572 discloses that a filter which 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, in which thin paper and a case holder 4 are provided on a floor surface 1 with a bottom surface 4 thereof.
a is painted black and fixed with a stopper 6 such as a screw, which also serves as a reflection plate, and a white thin paper (or cloth, synthetic resin, or the like) 8 is placed thereon. A case 12 whose bottom 12 a is formed of a transparent or translucent member is inserted into the holder 4.
4. Detection means 1 including light receiving means 16 and comparator
8 are integrally accommodated and connected to the outside via a cable 26. The case 12 is dustproof,
Although it also serves as a water-proof lid, in order to make it easier for the leaked liquid 2 to penetrate into the reflective area 8b in the center of the thin paper 8 and to shorten the time for detecting the leaked liquid, the gap between the bottom 12a of the case and the thin paper 8 is reduced. Is provided with a void 10. This gap avoids dirt such as dust and dust, and does not detect external noise light.
In order to stably detect the reflected light from the thin paper 8, it is desirable that the distance be within several mm. 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 radiated from the light source means 14 such as an LED, an infrared laser light emitting element, or an optical fiber.
Is constantly detected by the light receiving means 16. Thus, if a liquid leak 2 occurs on the floor surface 1,
The leaked liquid 2 sequentially permeates the reflection area 8b of the thin paper 8 from the contact portion 9, and the contact portion 9 of the thin paper 8 changes from white to transparent color due to the penetration of the leaked liquid. 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 leakage sensor using such thin paper has a simple structure, is reliable in operation, and is fixed to the floor surface with a stopper or the like. Although there is an advantage of being able to detect, a user who wants to minimize the work of installing the holder on the floor and replacing the thin paper as much as possible has demanded a liquid leakage sensor that does not use the thin paper and does not require the installation of the floor.

[0003]

As such a liquid leakage sensor which does not use thin paper, various types have been devised which irradiate the above-mentioned case with light and determine the presence or absence of liquid leakage based on the amount of reflected light. However, when the case bottom and the floor are brought into close contact with each other, a liquid having a high viscosity becomes very difficult to penetrate into the center of the case bottom. The structure was such that a gap was provided between the floor and the bottom of the case, and a large amount of liquid leaked out, and the liquid could not be detected at all unless the bottom of the case was in contact with the liquid. In the case of the structure where the bottom of the case is directly exposed to the floor surface, it is easily affected by the paint color of the floor surface, and unnecessary reflected light from the floor surface at the stage when the liquid has permeated. There is also a problem that determination of the presence / absence of liquid leakage is not stable only by the magnitude of the amount of reflected light, for example, a large amount of light is received and a malfunction occurs. In addition, since the case is simply placed on the floor without fixing it, an accident such as the case being lifted off the floor or falling over was likely to occur.
Therefore, the present invention has been made in view of the above-described circumstances, an object of the present invention is to use a thin paper that can detect a leak at an early stage even if the leak does not contact the bottom of the case, An object of the present invention is to provide a liquid leakage sensor with a fall detection function.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a liquid leakage sensor comprising at least one reflecting boundary surface capable of contacting liquid leakage, a light source means and a light receiving means. The light is projected onto the reflective boundary surface, the reflected light from the boundary surface is received by a plurality of light receiving means, and the outputs of these light receiving means are arithmetically processed to arrange the arrangement of the light and dark patterns of the reflected light at predetermined intervals. This is achieved by determining and determining the presence or absence of liquid leakage based on a change in the arrangement position of the light / dark pattern of the reflected light. Further, the present invention provides at least one reflective boundary surface that can come into contact with the liquid leak, a case whose bottom is made of a transparent material or a translucent material, light source means for irradiating light, and irradiating light from this light source. A first optical transmission unit that irradiates the reflective boundary surface through a transparent material or a translucent material of the case; a second optical transmission unit that receives and transmits light reflected from the boundary surface; The above object of the present invention also relates to a liquid leakage sensor comprising light receiving means for receiving light from the second light transmitting means, wherein one end of the first light transmitting means and one end of the second light transmitting means are optically connected. The second optical transmission means is constituted by a plurality of optical transmission means and transmitted so that the light receiving positions of the reflected light can be distinguished from each other. Receiving light reflected by the plurality of light receiving means at the other end of the second light transmitting means. The positions of the reflected light are converted into yellow light signals so that the positions can be distinguished from each other, and the outputs of these light receiving means are arithmetically processed to determine the arrangement of the light / dark pattern of the reflected light at predetermined intervals. It is also achieved by determining the presence or absence of liquid leakage based on the fluctuation. Further, the object of the present invention is to form at least two reflection boundary surfaces which can come into contact with the liquid leakage with a gas layer or a liquid leakage permeable layer interposed in the light traveling direction, and at least two light source means and light receiving means Are arranged on the same side with respect to each of the reflection boundary surfaces, and light from the first light source unit is incident on the first reflection boundary surface closest to the light source unit at an incident angle equal to or greater than the critical angle. A first leak sensor is formed by projecting and receiving the reflected light from the first boundary surface by a first light receiving unit, calculating the output thereof, and detecting a leak. Then, light is projected from the second light source means at an incident angle smaller than the critical angle to a reflection boundary surface other than the first boundary surface, and reflected light from a reflection boundary surface other than the first boundary surface is reflected. Is received by the second light receiving means, and the output thereof is subjected to arithmetic processing to the second detecting means for detecting the liquid leakage. Also achieved by configuring the second liquid leakage sensor.

[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 shows an example of a liquid leakage sensor 20a utilizing the arrangement of the light and dark patterns of the present invention. Devices having the same numbers perform the same functions and use thin paper 8. The bottom surface 4a of the holder 4 is, for example, painted in a halftone gray, and its reflected light 24 is a one-dimensional or two-dimensional photoelectric conversion element array sensor (hereinafter, referred to as a CCD or MOS photodiode). Array sensor) 2
The output is converted into a digital signal by an A / D converter 32 at a predetermined sampling period, and is sequentially written to a double buffer memory 34 in a controller 30 including a microprocessor (MPU) 36. It has become. A tilt sensor 38 is provided in the case 12, and its output is input to the control means 30, the detection output of the liquid leakage is output as an electric signal to the outside, and further output to the display means 29 by a red LED or the like. It is supposed to be. It is preferable that the holder 4 has a contact surface with the floor surface 1 whose outer diameter is at least 1.5 times the outer diameter of the case 12 from the viewpoint of preventing the sensor 20a from tipping over.
The distance d between the contact surface 12a of the bottom of the case 12 and the bottom surface 4a of the holder 4 and the bottom surface 4a of the holder 4 is preferably variable in accordance with the viscosity of the liquid to be detected. If the angle or the interval between the reflection boundary surface 4a and the light receiving means 28 changes due to the above, the malfunction may be caused. Therefore, the holder 4 and the case 12 can be attached and detached, and the interval d does not change with respect to external vibration. Structures are preferred.
Further, since 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 unnecessary reflected light from the floor surface. The operation of the above configuration will be described below. First, when there is no liquid leak 2, as shown in FIG. 2B, the reflected light 24 from the holder bottom surface (reflection boundary surface) 4a is output from the array sensors 28a to 28.
n, and the light and dark pattern forms a distribution as shown in FIG. When the leaked liquid 2 slightly penetrates the reflection boundary surface 4a, the reflected light 24a is reflected in FIG.
When the thickness (depth) of the leaked liquid further increases, the light and dark pattern shown in FIG. 3C is arranged. When the case 12 is submerged in the leaked liquid 2, the reflected light 24z becomes The arrangement changes to the arrangement of the light and dark patterns in FIG. Therefore, at a predetermined sampling period, the array sensor 2
After writing the outputs of the eight elements 28a to 28n into the double buffer memory 34, the following processing may be performed by an 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 leakage is determined based on whether or not this position is within the range of no leakage. b2) The center of gravity XG of the brightness distribution of the reflected light amount of the smoothed light receiving pattern 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 of no 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
In the light receiving pattern obtained by smoothing the waveform position similar to (j), the calculation is performed by the following equation.

(Equation 2) Next, at a position that is at least a predetermined distance from the no-leakage position,
In addition, when a light-dark pattern similar to the template waveform is detected with a predetermined similarity Thcr or more, it is determined that there is liquid leakage, and otherwise, it is determined that there is no liquid leakage. c) Thus, when a leak is detected, the display means 29 is lit in red and the presence or absence of the leak is output to the outside via the cable 26. In the processes b1) and b2), the reflected light is widely collected by a light condensing means such as a lens, so that the presence or absence of liquid leakage can be calculated by a minimum of two light receiving means. In the correlation calculation of b3), at least 4 to
It is preferable to collect reflected light data from eight different positions by the light receiving means. Therefore, according to the liquid leakage sensor having the structure shown in FIG. 2, only the liquid leakage sensor 20a is placed on the floor surface 1 without using the thin paper 8, the sensor fixing work on the floor surface is not required, and a large amount of leakage occurs. At the initial time when the liquid does not flow out and the liquid has permeated the reflective boundary surface 4a, the liquid can be reliably detected, and the sensor 20 can be detected by enlarging the outer periphery of the holder 4.
a can also be prevented from falling.

Next, FIG. 4 corresponding to FIG. 2 shows another embodiment of the liquid leak sensor 20b utilizing the arrangement of the light and dark patterns of the present invention. Optical transmission means 40, 42a-
42z is used to transmit and receive light to the reflective boundary surface 4a, so that even when the liquid 2 is volatile and there is a danger of ignition or explosion, it is possible to detect liquid leakage by reflected light very safely. The devices having the same numbers perform the same functions, and the light emitted from the light source means 14 provided at a remote location is transmitted to the case 12 by the optical transmission means 40.
Is guided to the reflection boundary surface 4a at a predetermined angle, and the reflected light is received by linearly arranged light transmission means 42a to 42z, and the light reception means 28a and 28b provided at remote locations are provided. To the AD conversion means 32
Is input to the control means 30 via the.
Even in such a configuration, the liquid leakage 2 is caused by the reflection boundary surface 4 of the holder 4.
a, the output of the light receiving means 28b is larger than the output of the light receiving means 28a, and when the leaked liquid 2 penetrates into the irradiation area of the reflection boundary surface 4a, the refraction of light by the leaked liquid 2 and Due to changes such as the output of the light receiving means 28a increasing due to the reflection phenomenon and the output of the light receiving means 28b decreasing,
The presence or absence of liquid leakage can be detected by the processing of b1) or b2) described above. Therefore, according to the liquid leakage sensor having a structure as shown in FIG. 4, only the liquid leakage sensor 20b is placed on the floor surface 1 without using the thin paper 8, and the work of fixing the sensor to the floor surface is unnecessary, and the volatile sensor is not volatile. Even when a small amount of liquid leaks into the reflective boundary surface 4a, it is possible to detect the liquid leak very safely for the liquid 2. 2 and 4, even if a large amount of liquid leaks out at once and the case 12 is submerged in the liquid leakage and bubbles or the like are generated at the case bottom 12a, the reflection boundary is not increased. If the liquid leaks into the surface 4a, the reflection path of the irradiated light is bent and the output of the light receiving means 28a, 28b and the like changes, so that the liquid leak should be detected without being affected by bubbles or the like. Becomes possible.

Next, FIG. 5 shown corresponding to FIG. 1 and FIG.
Shows another embodiment of the liquid leakage sensor 20c of the present invention. The devices having the same numbers perform the same functions and come into contact with the liquid leakage at the bottom of the case from the light source means 14a. Light 22a is irradiated to the reflection boundary surface 12a at an incident angle equal to or greater than the critical angle, the total reflection light 24a is received by the light receiving means 16a, and is converted into an electric signal. Bottom 4 of holder 4
The light 22b is irradiated at an incident angle smaller than the critical angle with respect to the second reflective boundary surface 7 in which the surface of the reflective member such as glass or synthetic resin adhered to the adhesive member 5 is formed with an unevenness. The light 24b is received by the light receiving means 16b or 28,
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 and the reflected light receiving surface in the vicinity of the light receiving means, unnecessary reflected light is emitted from the floor surface even when the floor surface is white or a mirror surface at the time of liquid leakage. There is an optical effect of not receiving light.
The operation of the liquid leakage sensor 20c in such a configuration will be described. When the inclination sensor 38 detects an inclination of a predetermined angle or more, an alarm signal is output to the outside. The output and the output of the capacitance sensor 39 are checked, and the amount of light reflected from the reflection boundary surface 7 decreases, or the capacitance sensor 3
If the output 9 changes beyond a predetermined range, it is determined that the leaked liquid 2 has approached the reflection boundary surface 7 or the case bottom 12a, and a leak detection signal is output to the outside. The light receiving means 16
When b is changed to a plurality of light receiving means 28 similar to that of FIG. 2, the reflection boundary surface 7 having the unevenness is not required. Furthermore, when a large amount of the leaked liquid 2 flows out to the floor 1 or the like at a time, the output of the light receiving means 16a also changes, so that the reliability of the leak detection can be further improved. Further, as shown in FIG. 5 (B), the irradiation light 22a and 22b are projected in directions orthogonal to each other, so that there is little optical interference between them. However, when the light source means 14a / 14b is turned on alternately, the light source Interference between them can be completely eliminated. It is preferable that the height d of the legs 12f of the case 12 be changed according to the viscosity of the liquid to be detected. Is preferable because the influence of the above can be eliminated. Furthermore, when the holder 4 is not used, the light receiving means 16b and the capacitance sensor 39 can be used as a sensor for floating the liquid leakage sensor 20c from the floor surface 1. Therefore, according to the liquid leakage sensor having the structure as shown in FIG. 5, a small amount of liquid leakage can be obtained without using thin paper which is a consumable, causing dust and the like, and without requiring the sensor to be fixed to the floor surface. Liquid leakage can be reliably detected at the time when the water has permeated the floor. Further, even if a large amount of liquid leaks at once, the detection of the liquid leak can be checked twice or three times by the capacitance sensor 39 and the total reflection boundary surface 12a, so that the reliability of the apparatus can be further improved.

Next, FIG. 6 corresponding to FIG. 4 and FIG.
Shows another embodiment of the liquid leak sensor 20d according to the present invention, in which the electric wire is not provided in the liquid leak detecting section, and the reflection boundary surface 12 is formed by the optical transmission means 40a and 40b such as optical fibers.
a and 7 are irradiated with light at an angle of incidence greater than or less than the critical angle, respectively, and the reflected light is transmitted to the light transmitting means 42a and 42b-4 to the light receiving means 16a / 16b provided at a remote place.
Since the liquid 2 is transmitted by 2z, even if the liquid 2 is volatile and there is a danger of ignition or explosion, the liquid leak can be detected by reflected light very safely. The case bottom portion 12a is covered or configured with a light shielding member 12g made of synthetic resin or the like except for the light irradiation surface and the reflected light receiving surface, and is integrally formed with the transmitted light member 12a. Has an optical structure that does not receive unnecessary reflected light from the floor surface even when the floor surface is white or mirror surface when the leaked liquid enters, Is partially transmitted to the case 12 by the optical transmission means 40b, and is radiated to the thin paper 8 placed on the floor 1 as light 22b at an incident angle smaller than the critical angle, and the reflected light 24b is reflected by the optical transmission means 42b to 42z. Is transmitted to the light receiving means 16b provided in a remote place, and the presence or absence of the liquid leakage 2 is checked. It is also possible to directly receive the reflected light from the floor surface 1 without placing the thin paper 8 on the floor surface 1. In the liquid leakage sensor 20d having such a configuration, even if the holder 4 is not provided, the liquid leakage sensor 20d is hardly affected by extraneous light.
There is an advantage that a leak can be detected quickly at the initial stage of leak out which does not flow out in large quantities up to 2a. In addition, since no electric signal flows through the liquid leakage detection unit, the detection processing can be performed extremely safely even for volatile liquid leakage. Even if a large amount of liquid leaks, this liquid leak is double-checked and triple-detected, and the reliability of the detection process can be further improved. Furthermore, the case head portion in which the above-mentioned light shielding member 12g and the transmitted light member 12a are integrally formed is shown in FIGS.
It is clear that the present invention can be applied to the liquid leakage sensor without the thin paper 8 shown in FIG.

[0009]

As described above, according to the optical leak sensor of the present invention, the leak can be detected simply by placing the leak sensor on the floor surface without using thin paper, and the layout of the sensor is realized. There is an advantage that change and construction work can be performed in an extremely short time. In addition, by attaching the holder 4 to the tip of the case containing the sensor in a detachable state, the effect of preventing the sensor from tipping over can be expected, and a liquid leakage detection process that is not affected by the paint color or surface properties of the floor can be performed. Furthermore, a highly reliable liquid leak sensor that does not malfunction even when subjected to vibration or shock such as an earthquake can be realized. Further, conventionally, it was not possible to detect a liquid leak unless the leaked liquid overflowed to the floor at a depth of 2 to 4 mm or more and flowed in large quantities. The leak can be sufficiently detected at the initial time when the water has permeated, and a serious leak accident can be prevented beforehand. In addition, if a sensor with no electrical wiring is used for the liquid leak detector, it will be volatile,
Liquids with a risk of flammable explosion can also be detected safely and reliably. Furthermore, the case head portion in which the light shielding member 12g and the transmitted light member 12a are integrally formed is hardly affected by extraneous light, and has an advantage that the structure of the case 12 can be simplified by eliminating the need for the holder 4.

[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 leakage sensor and a light reflection path of the present invention.

FIG. 3 is a diagram showing an example of an arrangement of a light-dark pattern of reflected light according to the present invention.

FIG. 4 is a diagram showing an example of an explosion-proof liquid leakage sensor of the present invention.

FIG. 5 is a diagram showing still another embodiment of the present invention.

FIG. 6 is a diagram showing an example of another explosion-proof liquid leakage sensor of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Floor surface 2 Liquid leakage 4 Holder 5 Adhesive 4a, 7, 12a Reflection boundary surface 8 Thin paper 12 Case 12g, 15 Light shielding member 14, 14a, 14b Light source means 16, 16a, 16b, 28 Light receiving means 20a-20d Liquid leakage sensor Reference Signs List 30 control means 32 AD conversion means 34 double buffer 36 MPU 40, 40a, 40b, 42, 42a, to 42z optical transmission means 38 inclination sensor 39 capacitance sensor

Claims (19)

[Claims] 1. A liquid leakage sensor comprising at least one reflection boundary surface capable of contacting a liquid leak, a light source means and a light receiving means, wherein light is projected from said light source means to said reflection boundary surface, and said boundary surface is provided. The reflected light from the
The output of these 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 by a change in the arrangement position of the light and dark patterns of the reflected light. A liquid leakage sensor. 2. The liquid leakage sensor according to claim 1, wherein 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. 3. A case in which at least one reflection boundary surface that can come into contact with the liquid leakage, a case whose bottom is made of a transparent material or a translucent material, light source means for irradiating light, and irradiating light from this light source A first light transmitting means for irradiating the reflective boundary surface via a transparent material or a translucent material of the case, a second light transmitting means for receiving and transmitting light reflected from the boundary surface, A liquid leakage sensor comprising light receiving means for receiving light from the light transmitting means, wherein one end of the first light transmitting means and one end of the second light transmitting means are integrated so as to form an optical path. And the second optical transmission means is constituted by a plurality of optical transmission means and transmitted so that the light receiving positions of the reflected light can be distinguished from each other, and the other end of the second optical transmission means The light receiving position of reflected light can be distinguished from each other by multiple light receiving means The output of these light receiving means is subjected to arithmetic processing 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 the change in the position of the light and dark pattern of the reflected light. A liquid leakage sensor characterized in that: 4. The liquid leakage sensor according to claim 3, wherein said optical transmission means is an optical fiber. 5. The liquid leakage sensor according to claim 1, wherein an arrangement position of the light-dark pattern of the reflected light is calculated by a correlation operation or a gravity center position of a luminance distribution of the reflected light amount. 6. The liquid leakage sensor according to claim 5, wherein the template light receiving data for the correlation operation is input in a state where the liquid has previously contacted the reflection boundary surface, and is stored in a predetermined memory. 7. A method according to claim 7, wherein light receiving data from said plurality of light receiving means is input using a double buffer, and light receiving data for sampling input and light receiving data for calculating an arrangement position of a bright / dark pattern of reflected light are separated. Item 7. The liquid leakage sensor according to any one of Items 1 to 6. 8. The liquid leakage sensor according to claim 1, wherein a gas layer through which liquid leakage can penetrate is interposed on the reflection boundary surface. 9. The liquid leakage sensor according to claim 1, wherein the light receiving unit is a one-dimensional photoelectric conversion element array sensor or a two-dimensional photoelectric conversion element array sensor. 10. The reflection boundary surface is formed of a non-transparent thin plate-like cap holder detachable from the case, and is less affected by the surface properties and surface color of the location of the liquid leakage sensor. 10. The liquid leakage sensor according to any one of claims 9 to 9. 11. 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. For each of the boundary surfaces, disposed on the same side, and projecting light from the first light source unit at an incident angle equal to or greater than the critical angle with respect to the first reflection boundary surface closest to the light source unit, The first light-receiving sensor is configured to receive the reflected light from the first boundary surface by the first light-receiving means and to calculate the output of the first light-receiving means to detect the liquid leakage. Light is projected from the second light source means to the reflection boundary surface other than the first boundary surface at an incident angle smaller than the critical angle, and reflected light from the reflection boundary surface other than the first boundary surface is converted to the second boundary light. Light is received by the light receiving means,
A second leak sensor comprising a second leak sensor including a second detecting means for detecting the leak by arithmetically processing the output. 12. The liquid leakage sensor according to claim 11, wherein 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. 13. A case in which a bottom portion is made of a transparent material or a translucent material, an outer boundary surface of which forms a first reflection boundary surface capable of coming into contact with liquid leakage, At least one second reflective boundary surface capable of contacting, light source means for irradiating light, and a light source for transmitting an irradiation destination from the light source means and irradiating the first reflective boundary surface with an incident angle greater than a critical angle. A first optical transmission means, a second optical transmission means for receiving and transmitting light reflected from the first boundary surface, and a first optical transmission means for converting a light reception signal from the second optical transmission means into an electric signal. And a first means for calculating the output to detect liquid leakage
And a third light transmitting means for transmitting irradiation light from the light source means and irradiating the second reflection boundary surface with an incident angle smaller than the critical angle. A fourth light transmitting means for receiving and transmitting reflected light from the second boundary surface, a second light receiving means for converting a light receiving signal from the fourth light transmitting means into an electric signal, A second leak sensor is constituted by an arithmetic processing of the output to detect a leak, and one end of the first optical transmission means and the second leak sensor are formed.
While configuring another optical system path at one end of the optical transmission means,
A liquid leakage sensor, wherein one end of the third optical transmission means and one end of the fourth optical transmission means are integrated so as to form a second optical path and housed in the case. . 14. The liquid leakage sensor according to claim 13, wherein said optical transmission means is an optical fiber. 15. The liquid leakage sensor according to claim 2, wherein a tilt sensor is built in the case, and an alarm signal is output when the case is tilted. 16. A light shielding member is coated on the inside of the bottom of the case except for a light irradiation surface and a reflected light receiving surface, and the light shielding member is operated as a proximity sensor. The liquid leakage sensor according to the item. 17. The bottom of the case is covered or integrally formed with a light-blocking member except for a light irradiation surface and a reflected light receiving surface, and is hardly affected by a surface property and / or a surface color of an installation location of the liquid leakage sensor. The liquid leakage sensor according to any one of claims 2 to 16, wherein: 18. The non-transparent thin plate-shaped cap holder detachably attached to the case, wherein the second reflection boundary surface is formed on the case,
The liquid leakage sensor according to any one of claims 11 to 16, wherein the liquid leakage sensor is hardly affected by the surface properties and surface color of the installation location of the liquid leakage sensor. 19. The liquid leakage sensor according to claim 17, wherein a white thin plate which is brought into a transparent state by contact with the liquid leakage is attached to the surface of the cap holder.