JP2003214976A - Liquid leakage sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid leakage sensor capable of precisely performing a detachment detection also with a small-sized structure. <P>SOLUTION: This liquid leakage sensor comprises a detection part 115 having a prescribed refractive index, which has an outer wall surface formed in a spindle shape with a flat head, the flat-head surface 132 being placed in parallel to a sensor mounting surface 130 in a normally mounted state. The light 120 emitted from a projection part 113 to the side wall 133 consisting of an inclined surface of the detection part 116 is reflected by the boundary surface of the detection part side wall 133 with the outside, the reflected light 122 is detected by a light receiving part 114, and a liquid leakage detection is performed on the basis of the change in light receiving quantity by the light receiving part 114. Further, the light 120 emitted to the detection part flat head surface 132 is reflected by the sensor mounting surface 130 in the normally mounted state of the detection part 116, the reflected light 122 is detected by the light receiving part 114, and the placed state detection of the detection part 116 is performed on the basis of the change in light receiving quantity by the light receiving part 114. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak sensor, and more particularly to a detachment detecting mechanism therefor.

[0002]

2. Description of the Related Art In factory facilities and other facilities, for example, liquid leakage from joints of liquid supply pipes causes causes of disasters, pollution of facilities, and waste of liquids. Need to detect. Therefore, conventionally, for example, an optical liquid leakage sensor has been used in which the bottom portion of the mounting body is used as a detection portion having a predetermined refractive index.

As shown in FIG. 6, the liquid leakage sensor includes a mounting body 10 having a predetermined refractive index, and a light projecting portion 12 and a light receiving portion 14 arranged inside the mounting body 10. Pre-recorded body 1
In No. 0, the inner and outer wall surfaces of the detection unit (exposed surface) 16 are formed in a triangular shape, and the apexes of the triangular shape are arranged so as to face the liquid leakage pan (sensor mounting surface) 18 below the joint of the liquid supply pipe, for example. It

The light 20 emitted from the light projecting unit 12 to the wall surface inside the mounting body is reflected at the boundary surface between the detecting unit 16 and the outside, and the reflected light 22 is detected by the light receiving unit 14, Liquid leakage is detected based on the change in the amount of light received by the light receiving unit 14.

That is, in the non-leakage state in which the liquid does not adhere to the detection unit 16, the refractive index of the detection unit 16 and the outside (air)
Since the difference between the refractive index and the refractive index is large, the reflectance at the boundary surface between the detection unit 16 and the outside is high. Therefore, most of the light 20 emitted from the light projecting unit 12 to the detecting unit 16 is reflected by the boundary surface between the detecting unit 16 and the outside, and the reflected light 22 is detected by the light receiving unit 14.

On the other hand, in the leaked state in which the liquid adheres to the detection unit 16, the difference between the refractive index of the detection unit 16 and the refractive index of the outside (liquid) becomes smaller than that in the non-leakage state, so that the detection unit. The reflectance at the interface between 16 and the outside becomes low. Therefore, a part of the light 20 emitted from the light projecting unit 12 to the detection unit 16 is reflected at the boundary surface between the detection unit 16 and the outside, but is transmitted to the outside (leakage) as compared with the reflected light. ) The proportion of light increases. As a result, the amount of reflected light detected by the light receiving unit 14 is reduced as compared with the non-leakage state, and this is detected as the liquid leakage state.

By the way, the liquid leakage sensor needs to be maintained by wiping off the liquid adhering to the detecting portion 16 with a cloth after the detection. Since the detection unit 16 faces the liquid leakage pan 18, if the detection unit 16 is fixed to the liquid leakage pan 18,
Maintenance after the detection becomes difficult.

Therefore, it is conceivable that a fitting for facilitating maintenance is fixed to the liquid leakage pan and the detector 16 is detachably provided on the fitting. As a result, the detector 16 can be attached to the fixture during monitoring, and the detector 16 can be removed from the fixture during maintenance after detection, which improves the maintainability.

[0009]

However, if the detector is detachably provided to the fixture, the detector is likely to come off from the fixture during monitoring although the maintainability is excellent. May not be performed properly. For this reason, in the type in which the detector is detachably attached to the fixture, it is necessary to detect the detachment of the detector. Conventionally, it is conceivable to separately provide a general electric type detachment sensor for the detection unit.

However, since the space for mounting the detector for detecting liquid leakage is very narrow, downsizing is required, and explosion-proof property against flammable liquid leakage is also required. For this reason, in the leak sensor, if the detachment sensor is provided separately for the detection unit, it may increase in size and impair the explosion-proof property. There was an urgent need to develop a technology that can detect large deviations with a small configuration.

Up to now, as a technique for detecting the mounting state of the detecting portion and preventing an abnormal mounting state, for example, Japanese Patent Laid-Open No. 9-72 is proposed.
Although the technique disclosed in Japanese Patent Publication No. 820 and the like exists, it is required to detect a stable mounting abnormality by using a more reliable means. The present invention has been made in view of the above problems of the prior art, and an object of the present invention is to provide a liquid leakage sensor having a small configuration and capable of accurately detecting deviation.

[0012]

In order to achieve the above-mentioned object, a liquid leakage sensor according to the present invention comprises a detecting section, a light projecting section,
The light emitted from the light emitting unit to the side wall formed by the slope of the detection unit is reflected by the boundary surface between the side wall of the detection unit and the outside, and the reflected light is detected by the light receiving unit. Then, the liquid leakage is detected based on the change in the amount of light received by the light receiving unit, and the light emitted from the light projecting unit to the flat head surface of the detecting unit is the sensor mounting surface in the normal mounting state of the detecting unit. Is reflected by
It is characterized in that the reflected light is detected by the light receiving unit, and the mounting state of the detection unit is detected based on a change in the amount of light received by the light receiving unit.

Here, the detection unit has a outer wall formed in a cone shape having a flat head, and in a normal mounting state, the flat head surface is mounted parallel to the sensor mounting surface and has a predetermined refractive index. Part. The light projecting unit irradiates the detection unit with light. The light receiving unit receives the light emitted by the light projecting unit and reflected by the boundary surface between the detection unit and the outside.

In the present invention, a fixture is provided,
The light emitted from the light emitting unit to the detection unit flat head surface is reflected by the opposing reflection surface of the fixture in the normal mounting state of the detection unit, and the reflected light is detected by the light receiving unit, It is preferable to detect the mounting state of the detection unit based on the change in the amount of light received by the light reception unit.

Here, the mounting member is disposed in parallel with the flat head surface of the detection unit in a normal mounting state of the detection unit, and the transmitted light from the flat head surface of the detection unit is again detected by the detection unit. An opposing reflection surface is provided for reflecting the light in the direction of the flat head surface so that the reflected light is detected by the light receiving unit, and the detection unit is detachably mounted on the sensor mounting surface.

The detection of the mounting state of the detection unit based on the change in the amount of light received by the light reception unit means that when the detection unit is removed, most of the transmitted light from the inside of the flat head surface of the detection unit to the outside is detected. Since the light is not reflected by the opposing reflecting surface of the fixture, the ratio of the amount of received light that returns to the detection unit and is detected by the light receiving unit is significantly reduced compared to the normal mounting state of the detection unit. This decrease in the amount of light received when the liquid comes off is clearly different from the amount of light received when liquid leakage is detected, so it is possible to detect this as a disconnection of the detection unit without erroneously detecting it as liquid leakage. .

The term "detector having a predetermined refractive index" as used herein means the difference between the refractive index of the detector and the refractive index of the outside (air) in a non-leakage state in which liquid does not adhere to the outer wall surface of the detector. Is larger, the reflectance at the boundary surface between the detector and the outside is higher. On the other hand, in the liquid leakage state in which the liquid adheres to the outer wall surface of the detector, the difference between the refractive index of the detector and the refractive index of the outside (liquid) becomes small, so the reflectance at the interface between the detector and the outside is small. Has a refractive index such that

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a schematic structure of a liquid leakage sensor according to an embodiment of the present invention. FIG. 1 (A) is a view of the entire apparatus as seen from above, and FIG. It is the figure which looked at the body from the side. It should be noted that the reference numeral 100 is added to the portion corresponding to the above-mentioned prior art to omit the description.

In the present embodiment, the leak sensor 124 is
The mounting body 110 and the attachment 126 are provided. Mounting tool 126
Is fixed to the liquid leakage pan (sensor mounting surface) 118 with a screw 128, and the mounting body 110 is removably mounted. The fixture 126 is provided with a counter reflection surface 130.

The counter reflection surface 130 is the detection portion 116 when the mounting body 110 is in a normal mounting state as shown in FIG.
The flat head surfaces 132 are closely contacted with each other so that they are arranged in parallel and opposite to each other. The inside of the mounting body 110 is, for example, a light projecting unit and a light receiving unit (not shown) formed of a ball-shaped glass lens or the like.
Are provided respectively.

An end portion of the light projecting side fiber 134 on the mounting body side is fixedly connected to the light projecting portion, and an end portion of the light projecting side fiber 134 on the side of the electrical system is located at an explosion proof location apart from the leak pan 118. Is removably connected to the light projecting side of the electrical system component 136 installed in. The light receiving side fiber 138 is provided in the light receiving portion.
Is fixedly connected to the receiving body side end of the receiving side fiber 13
An end portion of the electric system constituting portion 8 on the side of the electric system constituting portion 8 is detachably connected to the light receiving side of the electric system constituting portion 136.

The electrical system component 136 includes a light source 140 and
The light detector 142 and the determination circuit 144 are provided. The light source unit 140 emits light, and the light is emitted from the light projecting side fiber 134,
The inner wall surface of the detection unit 116 is irradiated with light through the light projecting unit inside the mounting body 110. The reflected light from the inside of the mounting body 110 is received by the light detecting unit 142 via the light receiving unit inside the mounting body 110 and the light receiving side fiber 138, and the light detecting unit 142 determines the received light amount information. Output to the circuit 144.

The determination circuit 144 includes a liquid leakage determination unit 146,
The detachment determination unit 148 is provided, and liquid leakage detection and placement state detection are performed based on the received light amount information from the light detection unit 142. That is, the liquid leakage determination unit 146 includes the information unit 150 that stores information necessary for liquid leakage determination. In this embodiment,
In the information section 150, the light detecting section 142 is set in advance in a non-leakage state and in a normal mounting state of the mounting body 110 with respect to the fixture 126.
The light receiving amount information by the light detecting unit 142 is obtained by the light detecting unit 142 in the liquid leakage state and the normal mounting state of the mounting body 110 with respect to the fixture 126.

In the non-leakage state in which no liquid leaks to the detection unit 116, the difference between the refractive index of the detection unit 116 and the refractive index of air is large, so that the boundary surface between the detection unit 116 and the outside is large. Has a high reflectance. For this reason, the detection unit 11
Most of the light emitted to 6 is reflected by the boundary surface between the detection unit 116 and the outside. The reflected light is collected by the light receiving section inside the mounting body 110, and is detected by the light detecting section 142 of the electric system constituting section 136 via the light receiving side fiber 138.

On the other hand, in the liquid leakage state in which the liquid has adhered to the detection unit 116, the difference between the refractive index of the detection unit 116 and the refractive index of the liquid becomes small, so that at the boundary surface between the detection unit 116 and the outside. The reflectance is low. Therefore, a part of the light emitted from the light projecting section inside the mounting body 110 to the inner wall surface of the detection section 116 is reflected at the boundary surface between the detection section 116 and the outside.
The ratio of transmitted light becomes larger than that of the reflected light. As a result, the amount of reflected light detected by the light detection unit 142 is reduced as compared with the non-leakage state, and this is determined as the liquid leakage determination unit 14.
It is detected as a liquid leakage state by 6.

The detachment determination unit 148 is used for the mounting body 11
An information unit 1 that stores information necessary for detecting the mounting state of 0.
52 is provided. In the information section 152, the photodetection section 142 is preliminarily set in the normal mounting state of the mounting body 110 with respect to the fixture 126.
The information on the amount of light received by the photodetector 142 and the information on the amount of light received by the photodetector 142 are obtained with the mount 110 removed from the fixture 126.

When the mounting body 110 is disengaged from the fixture 126, most of the transmitted light from the inside of the flat head surface 132 of the detector 116 to the outside is detected by the counter reflection surface 13 of the fixture 126.
Since the light is not reflected at 0, the ratio of the amount of reflected light returning to the inside of the mounting body 110 is significantly reduced as compared with the normal mounting.

The decrease in the amount of received light when the liquid is removed is clearly different from the amount of received light when the liquid leakage is detected. Therefore, the detachment determination unit 148 does not erroneously detect this as a liquid leakage state. It is accurately detected as a detachment of the body 110.

FIG. 2A shows the mounting body 110 shown in FIG.
A top view of FIG.
A side view of the same, and FIG.
Is shown from below. As shown in the figure, the mounting body 110 has a main body 154 having a hollow, substantially cylindrical shape. An inner wall surface at the center of the main body 154 is formed by a weight body having a square cross section, and a tip end of the weight body as the detection unit 116 is formed in a flat head shape.

The side wall 133 composed of the flat head surface 132 and the inclined surface, which is the detection section 116, is exposed from the bottom of the main body 154 so that the liquid adheres to the detection section 116 in the liquid leakage state.

Further, in the mounting body 110, on the bottom surface of the main body 154, the three legs 158, 160 and 162, for example, three leg portions 158, 160 and 162 are arranged at equal intervals on the same circumference near the outer periphery, and are the same as the exposed height of the detection portion 116. It is provided at a height. Accordingly, the detection unit 116
The mounting body 110 is supported on the liquid leakage pan in a state where the flat head surface 132 is firmly abutted on the opposing reflection surface of the fixture.

Further, the main body 154 is provided with a mounting body side connecting portion 164 made of, for example, a male side of a fastener.
The main body 154 of the mounting body 110 can be attached / detached to / from the mounting tool (not shown) via the connecting portion 164.

Further, FIG. 3A shows the mounting body 1 shown in FIG.
10 is a front view of the same, and FIG.
The figure which looked at 10 from the back is shown. As shown in the figure, the light projecting side opening 168 is formed in the mounting body side connecting portion 164.
And a light receiving side opening 170 is provided.

The projection side end (not shown) of the projection side fiber is inserted through the projection side opening 168, and the mounting body 1
It will be connected to a light projecting portion (not shown) inside 54. The light receiving side end portion (not shown) of the light receiving side fiber is inserted through the light receiving side opening 170 and connected to the light receiving portion (not shown) inside the mounting body 154.

FIG. 4A shows the attachment 126 shown in FIG.
A view of the same from above is shown in FIG.
The figure which looked at from the side is shown. The attachment 126
Is provided with a screw hole 174 in the main body 172.
74 is provided with the screw to attach the fitting 126 to the leak pan.
Is fixed.

The fitting 126 includes a counter reflection surface 130, and the counter reflection surface 130 is a plate portion for connecting the disc portion 130a functioning as a counter reflection surface and the disc portion 130a and the main body 172 of the fitting 126. Arm portion 130b and the like. The disk portion 130a is surface-treated to increase the light reflectance.

Further, the fitting 126 is provided with a fitting-side connecting portion 176 made of, for example, the female side of the fastener. The mounting body side connecting portion (not shown) can be attached / detached to / from the mounting tool side connecting portion 176 with one touch, so that the mounting body can be easily attached to and detached from the mounting tool 126.

The liquid leakage sensor 126 according to this embodiment is constructed as described above, and its operation will be described below.

First, the user cleans the detecting portion of the mounting body with a cloth or the like, attaches the mounting body to the fixture fixed to the liquid leakage pan, and starts liquid leakage monitoring. 5A and 5B show the detection principle of the leak sensor according to the present embodiment. FIG. 5A shows a normal mounting state of the mounting body, and FIG. It is in a detached state.

As shown in FIG. 3A, the flat head surface 1 of the detection unit 116 is in the normal mounting state of the mounting body with respect to the fixture 126.
The 32 is closely contacted with the opposing reflection surface 130 of the fixture 126 so as to be opposed to each other in parallel. Therefore, the light 1 emitted from the light projecting unit 112 to the inner wall surface of the detection unit 116
20 is reflected by the boundary surface between the side wall 133 formed by the inclined surface of the detection unit 116 and the outside, and the opposing reflection surface 130 of the fixture 126, and the reflected light 122 is detected by the light receiving unit 114.

Here, in the non-leakage state in which no liquid leaks to the detection unit 116, the difference between the refractive index of the detection unit 116 and the refractive index of air is large, so that the boundary surface between the detection unit 116 and the outside is large. Has a high reflectance. For this reason, the light 12 emitted from the light projecting unit 112 to the side wall 133 formed by the slope of the detection unit 116.
Most of 0 is reflected by the boundary surface between the detection part side wall 133 and the outside, and the reflected light 122 is detected by the light receiving part.

On the other hand, in the liquid leakage state in which the liquid is attached to the detection unit 116, the difference between the refractive index of the detection unit 116 and the refractive index of the liquid becomes small, so that the boundary surface between the detection unit side wall 133 and the outside. The reflectivity at is low. Therefore, a part of the light 120 emitted from the light projecting unit 112 to the side wall 133 formed by the slope of the detection unit 116 is reflected by the boundary surface between the detection unit 116 and the outside, but is reflected by the reflected light 122. The ratio of transmitted light becomes large in comparison. As a result, the amount of reflected light collected by the light receiving unit 114 is reduced as compared with the non-leakage state, so that the determination circuit can detect this as a leaking state.

Moreover, since the detecting portion 116 is formed of a flat-headed weight body, that is, since the side wall 133 having a slope is used, the incident light path of the light 120 and the reflected light path of the reflected light 122 are laterally offset. There is. As a result, in the present embodiment, the degree of freedom in arranging the light projecting section 112 and the light receiving section 114 is increased, as compared with the case where the side wall 133 is not formed of a slope. Further, since the reflected light 122 can be condensed while the influence of the incident light 120 is reduced by the light receiving section 114, the liquid leakage can be accurately detected.

Here, usually, the brightness, color, etc. of the leaking pan, which is the sensor mounting surface, are often different depending on each leaking pan, use environment, time, etc., while the optical sensor has high sensitivity. The light receiving section 114 is easily affected by fluctuations in the amount of light collected. In view of this, in the present embodiment, the fitting 126 is provided with the opposing reflection surface 130, and the flat head surface 132 of the detection unit 116 of the placement body is brought into contact with the opposing reflection surface 130 to place them in parallel.

As a result, in this embodiment, the fixture 126
If the opposite reflection surfaces 130 of the same type are the same, the transmitted light from the inside to the outside of the detection unit 116 is always reflected by the same opposite reflection surface in the normal mounting state of the mounting body 110. Therefore, the reflected light in the same environment can be condensed by the light receiving unit 114. Therefore, in the present embodiment, the total amount of the reflected light 122 obtained by the light receiving unit 114 in the non-leakage state can be made constant, and more accurate detection can be performed.
Further, after the detection, the mounting body 110 can be easily removed from the mounting tool 126, so that maintenance such as wiping the liquid adhering to the detection unit 116 with a cloth can be easily performed.

By the way, although the liquid leakage sensor is excellent in maintainability, there is a possibility that the mounting body may come off from the mounting tool during monitoring. If it comes off, it may not be possible to properly monitor the leakage, so it is necessary to detect the removal of the mounting body.

Therefore, according to the present invention, instead of separately providing a detachment sensor on the mounting body, one detector is used to detect detachment in addition to the liquid leakage detection. Therefore, in the present embodiment, the exposed detection unit 11
The outer wall surface of No. 6 is formed in the shape of a flat weight. Then, in a normal mounting state of the mounting body 110, the flat head surface 132 of the detection section 116 is closely attached to the counter reflection section 130 of the mounting tool 126 to be mounted in parallel.

As a result, in the present embodiment, as shown in FIG. 9A, the light 120 radiated on the inner wall of the flat head surface 132 of the mounting body detection unit 116 in the normal mounting state of the mounting body 110.
Most of the reflected light 122 is reflected by the facing reflection portion 130 of the fixture 126, and the reflected light 122 is collected by the light receiving portion 114.

On the other hand, as shown in FIG.
With 0 removed from the mounting tool 126, the flat head surface 132 of the mounting body detection unit 116 faces the reflecting surface 1 of the mounting tool 126.
More than 30. Then, most of the light 120 emitted to the flat head surface 132 of the detection unit 116 inside the mounting body from the light projecting unit 112 is transmitted to the outside from the inside of the flat head surface 132 of the detection unit 116. Most of the transmitted light is the fixture 1
The mounting body 110 is reflected again by the counter reflecting surface 130 of 26 and is placed again.
Since it does not return to the inside of, it is hardly detected by the light receiving part. The counter reflection surface 1 of the fixture 126 in the transmitted light
Even if something is reflected by 30, it hardly returns to the inside of the mounting body and is detected by the light receiving unit.

Therefore, in this embodiment, the mounting body 110 is used.
When is removed from the mounting tool 126, the ratio of the amount of reflected light that returns to the inside of the mounting body 110 and is condensed by the light receiving unit is
Significantly reduced compared to the normal mounting state of 0. Further, since the decrease in the amount of received light when the liquid is removed is clearly different from the amount of received light when the liquid is detected, it can be detected as the removal of the mounting body without erroneously detecting the liquid leakage state. .

That is, in the present embodiment, the detection section 116.
Is formed of a flat weight. That is, by forming the flat-faced surface 132 at the tip of the detection part, the area of the detection part used for the deviation detection can be increased as compared with a general detection part in which triangular vertices are arranged to face the liquid leakage pan. You can As a result, the light amount reduction amount in the normal placement state and the out-of-position state can be increased as compared with the one using the apex of the triangle. Therefore, in the detached state, a larger amount of light leaks to the outside as compared with the liquid leakage state in which the liquid adheres to the detection unit 116, and thus returns to the inside of the mounting body and is detected by the light receiving unit. There are few things. With this, it is possible to accurately distinguish the liquid leakage state in which the liquid is attached to the detection unit and the detached state, so that the liquid leakage detection and the mounting state detection can be accurately performed.

Further, in the present embodiment, since the liquid leakage detection and the mounting state detection are carried out by using the one detection unit, compared with the structure in which the liquid leakage detection mechanism and the detachment detection mechanism are separately provided, Since the size can be reduced, it is possible to prevent the freedom of the placement place of the placement body from being impaired. Moreover, in the present embodiment, since the detachment detection is also performed optically, it is possible to prevent the explosion-proof property from being impaired.

As described above, according to the liquid leakage sensor of the present embodiment, the detecting portion 116 of the mounting body 110 is formed in the shape of a flat head and the detecting portion flat head surface 132 is attached to the fitting 126.
Since it is mounted on the opposite reflection surface 130 of the above, it is possible to accurately detect the detachment of the mounting body 110 of the liquid leakage sensor, which has been extremely difficult in the past, with a small configuration while considering the explosion-proof property. it can. Moreover, in this embodiment, the counter reflection surface 1 is
Since the mounting body 110 is mounted on the leak pan 118 via the mounting tool 126 provided with the mounting tool 30,
The detection can be performed more accurately as compared with the case where 26 is not used.

The leak sensor of the present invention is not limited to the above-mentioned structure, but various modifications can be made within the scope of the gist of the invention. For example, in the above-described configuration, an example in which the mounting body detection unit is arranged so as to face the opposing reflection surface of the fixture has been described, but the liquid leakage sensor of the present invention is not limited to the above configuration, and the sensor mounting surface If the environment such as brightness and color is always the same and the sensor is not easily affected by the environment, the mounting body can be directly mounted on the sensor mounting surface such as the leak pan. However, the brightness, color, etc. of the sensor mounting surface often differ depending on the environment, time, etc. While the optical leak sensor has high sensitivity, it is affected by fluctuations in the amount of reflected light detected at the light receiving part. Because it is easy to receive
In order to reduce the influence and perform more accurate detection, it is necessary to dispose the mounting body detection unit so as to face the opposite reflection surface of the fixture.
Particularly preferred.

Further, in the above-mentioned configuration, the example in which the flat head surface of the detecting portion is brought into contact with the opposing reflecting surface of the mounting tool has been described. In addition, the flat head surface of the detecting portion is mounted parallel to the opposing reflecting surface of the mounting tool. If it is placed, it may be placed with a gap, but in order to make it difficult to be affected by the environment, it is possible to bring the flat head surface of the detection unit into contact with the opposing reflection surface of the fixture, Particularly preferred.

Further, in the above-mentioned configuration, an example in which the detection unit is provided with one flat-headed cone is described, but the liquid leakage sensor of the present invention is not limited to the above-described configuration, and two or more flat-headed cones are used. A body can be provided. However, it is particularly preferable to dispose two or more flat-headed cones so as to face the opposite reflection surface of the fixture in order to make it difficult to be affected by the environment.

[0058]

As described above, according to the liquid leakage sensor of the present invention, the outer wall surface of the detection portion is formed in a flat-headed weight shape, and the flat-headed surface serves as the sensor mounting surface in a normal mounting state. The light emitted from the light projecting unit to the inner wall surface of the detecting unit is provided in parallel with the detecting unit, and the light is reflected by the sensor mounting surface in the normal mounting state of the mounting body. Light is detected by the light receiving unit, and liquid leakage detection and placement state detection are performed based on the change in the amount of light received by the light receiving unit. Can be configured and accurate. Further, in the present invention, in the normal mounting state of the detection unit, the detection unit is arranged parallel to and facing the flat head surface of the detection unit, and the transmitted light from the flat surface of the detection unit is reflected again in the direction of the flat head surface of the detection unit. The counter reflection surface for detecting the reflected light at the light receiving unit is provided, and the detection can be performed more accurately by providing the sensor mounting surface with an attachment for detachably mounting the detection unit. .

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a schematic configuration of a liquid leakage sensor and a fixture according to an embodiment of the present invention.

FIG. 2 (A) is a view of a mounting body of a liquid leakage sensor according to an embodiment of the present invention viewed from above, and FIG. 2 (B) is a view of a similar mounting body viewed from a side. FIG. 3C is a view of a similar mounting body viewed from below.

FIG. 3A is a front view of a mounting body of a liquid leakage sensor according to an embodiment of the present invention, and FIG. 3B is a rear view of the same mounting body. is there.

FIG. 4A is a view of a fixture according to an embodiment of the present invention as seen from above, and FIG. 4B is a view of a similar fixture as seen from a side.

5A and 5B are explanatory diagrams of the detection principle of the liquid leakage sensor according to the embodiment of the present invention. FIG. 5A is a normal mounting state of the mounting body, and FIG. 5B is the same mounting state. It is explanatory drawing of a detached state of a body.

FIG. 6 is an explanatory diagram of a detection principle of a general liquid leakage sensor.

[Explanation of symbols]

110 Placement 112 Projector 114 Light receiving part 116 detector 118 Leak pan (Sensor mounting surface) 126 Fixture 130 Opposite reflection surface 132 Detection unit Flat head 133 Side wall of detection unit

Claims (2)

[Claims] 1. A detector having a predetermined refractive index, the outer wall of which is formed in the shape of a cone having a flat head, and in a normal mounting state, the flat head surface is mounted parallel to the sensor mounting surface, and the detector. And a light receiving unit for receiving the light emitted by the light projecting unit and reflected by the boundary surface between the detecting unit and the outside. The light radiated to the side wall formed by the inclined surface is reflected by the boundary surface between the side wall of the detection unit and the outside, the reflected light is detected by the light receiving unit, and the liquid leakage is detected based on the change in the amount of light received by the light receiving unit. The light radiated to the detection unit flat head surface from the light projecting unit is reflected in the sensor mounting surface in the normal mounting state of the detection unit, and the reflected light is detected by the light receiving unit, A liquid leakage sensor, which detects a mounting state of the detector based on a change in the amount of light received by the light receiver. 2. The liquid leakage sensor according to claim 1, wherein the detection unit is placed in a normal state and is disposed so as to face the flat head surface of the detection unit in parallel, and the transmitted light from the flat surface of the detection unit is again detected. An attachment tool is provided, which is provided with an opposing reflecting surface that reflects in the direction of the flat head surface of the detection unit and allows the light receiving unit to detect the reflected light, and detachably mounts the detection unit on the sensor mounting surface. The light emitted from the light projecting unit to the flat head surface of the detection unit is reflected by the opposing reflection surface of the fixture in a normal mounting state of the detection unit with respect to the fixture, and receives the reflected light. A liquid leakage sensor, characterized in that the mounting state of the detector is detected based on a change in the amount of light received by the light receiver.