JP2000298177A - Freezing detection sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a freezing detection sensor enabling freezing of a road surface or the like to be detected with accuracy by means of a simple and economical arrangement of a system. SOLUTION: Water 2 is retained in a container 1 and a vertically movable lever 3 is installed therein. An optical fiber 4 is passed over the lever 3 and a bend imparting part 5 for the optical fiber 4 is provided. The lever 3 is moved upward by an increase in volume of the water 2 resulting from freezing and pushes up a projecting adapter 9 so as to bend the optical fiber 4 between the projecting adapter 9 and a recessed adapter 8. An increase in light transmission losses caused by the bending is measured to detect whether or not the water has frozen.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor for detecting freezing using an optical fiber in order to detect freezing on a road surface or the like.

[0002]

2. Description of the Related Art Conventional methods for detecting the freezing of a road surface include, for example, a method of photographing the road surface with a camera and judging whether or not the road surface is frozen based on an obtained image, or a method using a light wave type sensor. There is a method in which the height and the amount of reflected light from the road surface are measured, and freezing is estimated based on a combination of the measured data and the measured data of the road surface temperature.

[0003]

A method for determining freezing from an image captured by a camera requires an image transmission apparatus and a power supply for the apparatus. Also, the method of measuring the road surface height and the amount of reflected light with a light wave type sensor requires the provision of a power supply for driving the device at the set point (observation point) of the device, and both methods require a complicated and expensive freeze detection system. become.

In addition, these methods have low detection reliability and often cause erroneous detection.

Accordingly, an object of the present invention is to provide a sensor that does not require a power source at an installation location and that more accurately detects freezing.

[0006]

According to the present invention, there is provided a freeze detecting sensor comprising: a container for storing water; a lever installed in the container so as to be vertically movable; an optical fiber laid in a fixed position;
A bending portion that increases the transmission loss of the optical fiber, the lever is displaced by an increase in volume due to freezing of water in the container, and the bending portion is actuated by the displacement motion to cause the optical fiber to move. The characteristic is that it is bent.

That is, when the water in the container freezes, the volume increases and the lever is pushed upward, and the displacement motion of the lever is transmitted to the bending portion, and the bending portion bends the optical fiber. To detect freezing by detecting an increase in transmission loss. Therefore, freezing can be reliably detected even if there is no power supply at the observation point.

In this freeze detection sensor, the lever is formed by a hollow body having an opening at a lower portion and a sealed upper portion.
It is preferable that the inside of the hollow lever is filled with water in the container, and a part of the water filling portion of the lever projects above the water surface in the container at the lowest point of the lever. In this way, the portion of the lever projecting above the water surface in the container is easily cooled, and when the outside air temperature falls below the freezing point, the water in the lever rapidly freezes, so that the lever is likely to be displaced (up). The detection power increases.

It is also preferable to provide a support which supports the lever so as to be able to move up and down and keeps the posture of the lever constant. The displacement of the lever can be accurately transmitted to the bending section without loss,
More reliable detection.

The bending portion may have a structure in which an optical fiber is arranged between a pair of corrugated blocks, for example.
When the water in the container is not frozen, the lever does not press the corrugated block, and the pair of corrugated blocks is separated so that the optical fiber interposed therebetween is kept straight. Also, if the lever rises during freezing and pushes up one waveform block, the optical fiber is clamped between the other waveform block and bent,
During freezing, the transmission loss of the optical fiber increases.

The optical fiber is led into a monitoring center, a relay station, or the like. Then, an E / O, O / E converter (electrical / optical, optical / electrical converter) or OTDR (Op
physical Time Domain Reflect
ometer: an optical time reflection measuring device) to construct a freeze detection system using the above-described freeze detection sensor. In this system, a frozen signal is extracted from an E / O / O / E conversion device based on a decrease in light intensity due to an increase in optical transmission loss, and an OTDR detects an increased transmission loss due to freezing.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a freeze detection sensor according to the present invention will be described below with reference to the accompanying drawings.

FIGS. 1 and 2 are cross-sectional views showing the entire structure of the freezing detection sensor. FIG. 1 shows a state where it is not frozen, and FIG. 2 shows a state where it is frozen. FIG. 3 shows an outline of a freeze detection system configured by connecting an exemplary freeze detection sensor to an E / O and O / E converter.

As shown in FIG.
Is a container 1, water 2 stored in the container 1, a lever 3 which is vertically movable in the container 1, an optical fiber 4 held linearly above the container 1, and an optical fiber 4 And a bending imparting portion 5 that causes the bending. Reference numeral 6 denotes a support that supports the lever 3 so as to be able to move up and down and holds the lever 3 in an upright state. The lever 3 is a hollow lever having an open lower portion and a closed upper portion, and is filled with water 2 so that air does not enter the inside. And this lever 3
In the state shown in FIG. 1 at the lowest point, a part of the water-filled portion of the lever 3 is projected above the water surface in the container 1. Since the air is prevented from entering the inside of the lever 3, the water level in the lever 3 can be kept higher than the water surface in the container 1 by the surface tension of the water as shown in the figure.

The bending portion 5 is attached to the cover 11 or the like and fixedly held at a fixed position, the convex adapter 9, and the convex adapter 9 are suspended below the concave adapter 8 so as to be vertically slidable. The convex adapter 9 is guided by the slide guide 10 and moves up and down.

FIG. 2 shows a state in which the temperature has dropped and the water has frozen to form ice 7. When the water freezes, the volume increases, and the lever 3 rises. The raised lever 3 pushes up the convex adapter 9, whereby the convex adapter 9 enters the recess of the concave adapter 8 and bends the optical fiber 4. Here, the convex adapter 9 is independent, but may be integrated with the lever 3. Even if the lever 3 is of a float type, its displacement occurs when the water in the container 1 freezes.

In a state where the water 2 is not frozen, as shown in FIG. 1, the optical fiber 4 is not bent, so that little transmission loss occurs. However, when the water 2 is frozen and becomes as shown in FIG. The optical fiber 4 is bent and the transmission loss increases. Therefore, the presence or absence of freezing can be known based on the change in the transmission loss.

As shown in FIG. 3, the optical fiber 4 of the freeze detection sensor 21 is connected to an E / O / O / E converter 22.
Further, an output signal from the E / O / O / E conversion device 22 is sent to a processing device (or a transmission device) 23. When freezing occurs and the transmission loss of the optical fiber 4 increases, E / O, O / E
The converter 22 detects that the power of the detection light has attenuated, and a signal from the detector 22 is sent to the processor 23 to determine that the processor 23 is frozen. If an alarm or the like is issued based on the result, a slip accident or the like due to freezing of the road surface can be prevented.

FIG. 4 shows an example in which a plurality of freeze detection sensors 21 are connected in series, and the end of the optical fiber 4 is connected to the OTDR 24. With the OTDR 24, it is possible to observe at which part of the optical fiber transmission loss has occurred, so that even if there are a plurality of observation points, it is possible to specify the freezing point.

FIG. 5 shows an example in which a water replenishing means is added as a countermeasure when the water 2 stored in the container 1 is reduced due to drying or the like. The freezing detection sensor 21 includes a tank 12 containing refilling water, and replenishes the container 1 with water from the tank 12 via a hose 13. This method is a method implemented in a general petroleum stove or the like. When the water level in the container 1 decreases to a certain level, a valve (not shown) attached to the end of the hose 13 opens. When water is replenished from the tank 12 and the water level in the container 1 recovers, the valve closes and replenishment stops. Therefore, the water surface in the container 1 can be maintained at a substantially constant level.

[0021]

As described above, the freezing detection sensor according to the present invention does not require a signal transmission device or a power supply at the observation point, so that a very simple and economical freezing detection system can be constructed and the freezing detection system can be used. Freezing can be reliably detected. Further, even when there are a plurality of observation points, the system is not complicated, and the location of the occurrence of freezing is accurately specified.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment (at the time of non-freezing) of a freeze detection sensor of the present invention.

FIG. 2 is a schematic diagram illustrating an example of a sensor freeze detection system of FIG. 1;

FIG. 3 is a schematic diagram of an example of a freeze detection system using the sensor of FIG. 1;

FIG. 4 is a schematic diagram of another example of a freeze detection system using the sensor of FIG. 1;

FIG. 5 is a sectional view of a sensor to which a water replenishing means is added.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Water 3 Lever 4 Optical fiber 5 Bending part 6 Support tool 7 Ice 8 Concave adapter 9 Convex adapter 10 Slide guide 11 Cover 12 Tank 13 Hose 21 Freeze detection sensor 22 E / O, O / E conversion device 23 Processing Equipment 24 OTDR

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsuneo Mori 1-3-1 Shimaya, Konohana-ku, Osaka-shi Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Mitsuo Mukose 1-1-1 Shimaya, Konohana-ku, Osaka-shi No. 3 Sumitomo Electric Industries, Ltd. Osaka Works (72) Inventor Masakazu Miyauchi 1-3-1, Shimaya, Konohana-ku, Osaka City Sumitomo Electric Industries Co., Ltd. Osaka Works

Claims (5)

[Claims] 1. A container for storing water, a lever installed vertically movable in the container, an optical fiber laid in a fixed position, and a bending portion for increasing a transmission loss of the optical fiber. A freezing detection sensor wherein the lever is displaced by an increase in volume due to freezing of water in the container, and the displacing movement activates the bending applying portion to bend the optical fiber. 2. The lever is formed of a hollow body whose lower part is open and whose upper part is sealed, and the inside of the lever of this hollow body is filled with water in a container. The freezing detection sensor according to claim 1, wherein a part of the filling portion protrudes above the water surface in the container. 3. The freezing detection sensor according to claim 1, further comprising a support that supports the lever so that the lever can be moved up and down and keeps the position of the lever constant. 4. The freezing detection sensor according to claim 1, further comprising a water replenishing means for supplying water to the container to keep the water level in the container substantially constant. 5. The freezing detection sensor according to claim 1, wherein an electrical / optical, optical / electrical conversion device, or an optical time domain reflectometer is connected to the optical fiber.