WO2007108095A1

WO2007108095A1 - Optical oil detector

Info

Publication number: WO2007108095A1
Application number: PCT/JP2006/305568
Authority: WO
Inventors: Koichiro Miyo; Haruhiko Seto; Hajime Seki; Atsushi Okuda
Original assignee: The Tokyo Electric Power Company, Incorporated; Ihi Scube Co., Ltd.
Priority date: 2006-03-20
Filing date: 2006-03-20
Publication date: 2007-09-27
Also published as: CN1989395A; CN100472187C

Abstract

An optical oil detector for detecting oil leaked into water by an optical fiber. The optical oil detector has a float (17a) floating on the water and moving up and down according to a variation in the water level, a fiber sensor (42) fixed to the float (17a) and moving up and down with the float (17a), a light emitting element provided at one end of the fiber sensor (42) and transmitting light to the fiber sensor (42), and a light receiving element provided at the other end of the fiber sensor (42) and converting the light inputted from the fiber sensor (42) into an electric signal.

Description

Specification

Optical oil detector

Technical field

[0001] The present invention relates to an optical oil detector.

Background art

[0002] Optical oil leak detectors are used as devices for detecting oil leaks in facilities such as underground passages where cables are laid and drainage pits. This oil leakage detector uses the property that an optical fiber is used as an oil sensor (fiber sensor), that is, if oil leakage adheres to the surface of the optical fiber, the amount of light leakage increases and the optical transmission loss of the optical fiber increases. (See Patent Document 1). This oil leak detector is used, for example, when detecting oil leaking into the water installed in the drain pit.

As shown in FIG. 7, such an optical oil leakage detector 1 includes a fiber sensor 2 whose tip is immersed in water W in the drain pit P, and a sensor support bracket 3 that supports the fiber sensor 2. And a sensor flange 5 that fixes the sensor support bracket 3 to the grating cover 4 of the drainage pit P, a converter 6 that is provided at the other end of the fiber sensor 2 and performs optical Z-electric conversion, and is connected to the converter 6. Monitoring device 7. When the oil leaks into the drain pit P and enters the water W, the oil leak is detected by the fiber sensor 2 and transmitted to the monitor 7 via the converter 6 (see Non-Patent Document 1). .

Patent Document 1: Japanese Patent Publication No.59-20092

Special noon literature 1: http://www.iscube.co.jp/seihin/ seihin_oil.html

Disclosure of the invention

Problems to be solved by the invention

[0004] However, such a conventional optical oil leakage detector has the following problems.

In other words, since the refractive index of water and air is different, if the water level in the water pit P suddenly changes, the ratio between the part where the fiber sensor 2 is in contact with water and the part where it is in contact with air changes greatly. The amount of light leakage from the fiber sensor 2 increases or decreases. This causes a malfunction of oil leakage detection. There was a possibility of causing. Also, from the drain pit P to the light receiving element of the converter 6, it is necessary to install an optical cable at the installation site according to the situation at the site. However, the installation work of the optical cable required special skills such as optical cable terminal processing, which hindered easy installation.

In addition, bacteria may adhere to the fiber sensor 2 and the bacteria may take in foreign matter, which may cause the oil leakage detection to malfunction or the fiber sensor 2 to deteriorate early.

[0005] The present invention has been made in view of the above circumstances, and can prevent malfunction and can be easily laid to prevent malfunction of oil leakage detection and early deterioration of the fiber sensor. An object is to provide an optical oil detector capable of this.

Means for solving the problem

[0006] The optical oil detector of the present invention includes: a float; an optical fiber fixed to the float; a light-emitting element that makes light incident on one end of the optical fiber; And an optical oil detector that detects oil based on a change in the amount of light leakage that occurs when oil adheres to the optical fiber.

According to the present invention, since the optical fiber as a sensor floats on the water surface together with the float, there is almost no change in the ratio of water to air in contact with the optical fiber even if a sudden water surface fluctuation occurs.

[0007] In the optical oil detector of the present invention, the light emitting element and the light receiving element may be housed in the float.

In the present invention, it is not necessary to lay the fiber sensor outside the drain pit or the like as in the prior art. In other words, it is possible to perform all terminal processing of optical fibers that require special skills in the float manufacturing process at the factory. In addition, when the fiber sensor is extended to the converter as in the past, it was necessary to install the converter within the fiber sensor installation distance (approximately 20 m). According to the present invention, since the light emitting element and the light receiving element are built in the float, the wiring extending from the float may be a normal electric cable. Therefore, there is no limitation on the installation location.

[0008] The optical oil detector of the present invention includes: a float; an optical fiber fixed to the float; A light-emitting element that makes light incident on one end of the optical fiber; a light-receiving element that converts the light emitted from the other end of the optical fiber into an electrical signal; and supplies power to the light-emitting element and outputs the light-receiving element A substrate having a circuit for amplifying the light; and a metal casing housed in the float together with the light emitting element, the light receiving element, and the substrate, and covering the light emitting element, the light receiving element, and the substrate.

According to the present invention, since the light emitting element, the light receiving element, and the substrate are covered with the metal casing, it is possible to constitute an intrinsically safe explosion-proof structure in combination with the explosion-proof barrier. Therefore, there is no limitation on the installation location.

In the optical oil detector of the present invention, a spherical curved surface may be provided on the outer periphery of the float, and an optical fiber may be provided along the spherical curved surface.

According to the present invention, it is possible to attach an optical fiber to a float while maintaining an appropriate curvature, and therefore it is possible to prevent an increase in light leakage due to excessive bending of the optical fiber.

[0010] In the optical oil detector of the present invention, the float is provided with a protrusion protruding outward from the optical fiber.

ADVANTAGE OF THE INVENTION According to this invention, it can prevent that an optical fiber contacts and damages an external object.

[0011] In the optical oil detector of the present invention, the float includes, as a casing, a trunk portion having an opening at an upper portion and a lid body that seals the opening of the trunk portion in a waterproof state, and the weight balance of the float When the float floats on the water, the water line is set so that it is located slightly below the joint between the lid and the trunk.

According to the present invention, the joint between the body and the flange is always located on the water surface. Therefore, the possibility of flooding into the float can be reduced. In addition, since the waterline is located sufficiently above the float, that is, most of the float is located in the water, the posture of the float can be kept stable. Preferably, the center of gravity of the float is positioned at the bottom by providing a ballast at the bottom of the float. This can further stabilize the posture.

[0012] It should be noted that the buoyancy of the upper portion increases as the shape of the body portion is tapered downward. Receive. Accordingly, the center of gravity can also be lowered by this, and the posture of the float can be stably maintained as described above.

[0013] The optical oil detector of the present invention may further include sterilization means for sterilizing the optical fiber.

According to the present invention, since bacteria and foreign matter do not adhere to the fiber sensor from which the outer surface coating of the optical fiber is peeled off, it is possible to prevent malfunction of oil leakage detection and early deterioration of the fiber sensor.

The invention's effect

[0014] According to the optical oil detector of the present invention, since the sensor is a float type, the positional relationship between the sensor and the water surface is always constant, and the amount of light leakage does not increase or decrease even under sudden water level fluctuations. In addition to stable oil leak detection, no special additional processing is required for installation in existing water tanks, so an optical oil detector can be additionally installed with minimal installation man-hours. The built-in optical / electrical conversion function in the float makes it possible to carry out all optical fiber terminal processing that requires special skills during the float manufacturing process at the factory. Therefore, the relay of the cable is easy and the local construction becomes easy.

[0015] On the other hand, the installation location is limited by the provisions of Article 42 of the Industrial Safety and Health Act, if the optical Z-electric conversion function is built in the float and the part having the function does not have explosion-proof performance. However, since the light-emitting element, light-receiving element, and substrate are covered with a metal casing, an intrinsically safe explosion-proof structure can be configured by combination with an explosion-proof barrier. Therefore, the installation location can be used without being limited.

In addition, the fiber sensor is used in a state where the outer surface coating of the optical fiber is peeled off. However, by providing a disinfecting means for disinfecting the optical fiber, bacteria and foreign substances do not adhere to the fiber sensor, so that it is stable. Oil leakage can be detected and the durability of the fiber sensor can be improved.

Brief Description of Drawings

FIG. 1 is a perspective view of a float used in a float type optical oil detector shown as an embodiment of the present invention. 2] Fig. 2 is a longitudinal sectional view of the float.

3] Fig. 3 is a vertical cross-sectional view of the float, and is a cross-sectional view taken along the line AA in Fig. 2.

[FIG. 4] FIG. 4 is a top view showing an outline of the laying state of the float type optical oil detector.

[FIG. 5] FIG. 5 is a side view showing an outline of the laying state of the float type optical oil detector and including a drainage pit.

FIG. 6 is a cross-sectional view showing the configuration of the fiber sensor.

FIG. 7 is a diagram showing a schematic configuration of a conventional optical oil detector.

Explanation of symbols

[0017] 7: Monitor, 17: Float type optical oil detector, 17a: Float, 19: Substrate, 34: Light emitting element, 35: Light receiving element, 42: Fiber sensor, 60: Rod, P: Drainage pit

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In the following description, the same reference numerals are used for the same configuration as the conventional one, and the description thereof is omitted.

[0019] FIG. 1 is a perspective view showing the main part of the float type optical oil detector 17 according to the present embodiment, that is, the configuration of the float 17a, FIG. 2 is a longitudinal sectional view of the float 17a, and FIG. —Vertical sectional view along line A, FIG. 4 is a top view showing the overall configuration of the float type optical oil detector 17, and FIG. 5 is a side view showing the overall configuration of the float type optical oil detector 17. .

[0020] The float 17a in the present float type optical oil detector 17 is provided with a resin-made casing 18 sealed in a waterproof state, a substrate 19 provided in the casing 18, and a lower part in the casing 18 as well. With 20 ballasts. The casing 18 has an opening in the upper part, a tapered part that is narrow at the bottom, and a lower end that is a closed end having a spherical curved surface, and a lid that covers the upper opening of the trunk part 18a in a waterproof state. 18b and a cover 18c covering the connectors provided on the lid 18b. As shown in FIG. 3, the lid 18b is bolted to the barrel 18a with waterproof O-rings 22a and 22b sandwiched between the barrel 18a. The protective cover 18c can protect the fiber sensor 42 and the cable 25 while maintaining an appropriate curvature. [0021] The ballast 20 is fixed to the lower end portion inside the body portion 18a by a bolt 21. When the float 17a floats on the water, the ballast 20 adjusts the weight so that the reference water level (draft) WL in FIG. 2 is positioned slightly below the joint between the lid 18b and the trunk 18a. Used for. The ballast 20 is divided into a first piece 20a and a second piece 20b, and the mounting hole 20c of the first piece 20a has a long hole shape. Accordingly, the first piece 20a can be eccentric from the center of the moon part 18a and fixed to the moon part 18a, and the inclination of the float 17a is suppressed by the eccentricity.

[0022] The substrate 19 has a donut shape, is mounted with the light emitting element 34 and the light receiving element 35, and is in a horizontal position so that the light emitting element 34 and the light receiving element 35 face the connectors 43B and 44B. Is housed in. The metal casing 23 is fixed in the casing 18 by a spacer 36 fixed to the inner surface side of the lid 18b. On the substrate 19, a power supply circuit that supplies power to a light emitting element 34, which will be described later, and an amplifier circuit that amplifies the output of the light receiving element 35 are formed.

The metal casing 23 includes an aluminum lower casing 23a and an aluminum upper casing 23b, and has a protective structure of IP20 or higher. IP standardizes protection against intrusion of foreign substances and protection against water intrusion, and indicates the protection structure of equipment stipulated by IEC standards. Here, IEC is an abbreviation for International Electrotechnical Com mission, which is the International Electrotechnical Commission where North America, South America, Europe and Asian countries are members. IP20 means that fingertips or similar fingertips with a length not exceeding 80 mm are not likely to come into contact with internal charging or moving parts, and that solid objects exceeding 12 mm in diameter will not enter the inside. To meet. The essence stipulated in the explosion-proof construction standards for electrical machinery and equipment based on the provisions of Article 42 of the Industrial Safety and Health Act, when the light-emitting element 34, the light-receiving element 35 and the substrate 19 are housed in a metal housing 23 and combined with an explosion-proof barrier. It conforms to the safety explosion-proof structure and can be used in hazardous areas.

[0023] The float 17a is provided with a fiber sensor 42 around the outer periphery of the casing 18. The fiber sensor 42 is made of a single-core optical fiber made of plastic, and is guided by a guide portion 18 d provided on the side wall of the casing 18 and a guide portion 18 e provided on the bottom. Here, as shown in FIG. 2, since the fiber sensor 42 is provided along the spherical curved surface of the casing 18 (body 18a), leakage of light caused by excessive bending of the fiber sensor 42 is prevented. Can be suppressed.

Further, as shown in FIG. 2, the guide portions 18d and 18e are provided in the casing 18 so as to protrude outward from the fiber sensor 42 wound around the outer periphery of the casing 18, and thereby the fiber The sensor 42 can be prevented from being damaged by contact with an external object. Each guide portion 18d, 18e is formed with a screw hole 18f so that a protective material for protecting the optical fiber can be installed. At the bottom of the casing 18, a slit 18 g having the same outer diameter as the optical fiber is formed so that the optical fiber can be easily guided. Furthermore, the guide portion 18e is a base that supports the float 17a when not in use, and a rod 60 described later is fixed when in use.

[0024] The fiber sensor 42 has light emitting side and light receiving side fiber connectors 43A,

44A, and these fiber connectors 43A and 44A are respectively fixed to connectors 43B and 44B provided on the lid 18b. A light emitting element (LED) 34 and a light receiving element (photodiode) 35 are provided for the connectors 43B and 44B, respectively, on the inner surface side of the lid 18b (inside the float 17a). The light emitting element 34 and the light receiving element 35 are electrically connected to the substrate 19 by wiring.

[0025] A cable 25 connected to the monitoring device 7 is also detachably fixed to the lid 18b.

The cable 25 is a cable for supplying electric power to the substrate 19 from the outside and outputting the output of the light receiving element 35 converted into an electric signal to the monitoring device 7. The cable 25 is detachably fixed by a cable clamp 56 provided at the center of the lid 18b, and the cable 25 fixed to the cable clamp 56 is electrically connected to the substrate 19 inside the float 17a. . The cable cleat 58 is fixed to the lid 18b by a bolt that joins the body 18a of the casing 18 and the lid 18b. The cable cleat 58 can hold and fix the cable 25. Since the cable 25 pull-out direction can be fixed by the Cape Nore Cleat 58, the center of gravity is adjusted by the ballast 20 so that the float 17a does not tilt due to the weight of the cable 25.

[0026] A porous copper plate (sanitization means) 38 is screwed into the screw hole 18f in the guide portion 18d. Are attached via screws. The fiber sensor 42 may malfunction as a leaked oil by increasing the optical transmission loss due to adhesion of bacteria or foreign substances. In addition, the optical fiber core itself may be eroded by deposits and may deteriorate early. Therefore, by attaching the copper plate 38, it is possible to protect the fiber sensor 42 and to suppress bacterial adhesion by killing bacteria by the trace metal action of copper. It is also possible to attach a plastic cover 39 to the copper plate 38 and store a disinfectant or the like inside.

Next, a detailed configuration of the fiber sensor 42 will be described.

As shown in FIG. 2, in the fiber sensor 42, the coating is peeled over a predetermined detection range, and the core wire (optical fiber core wire) is exposed. This detection range includes the range above and below the water level WL, but the part of the fiber sensor 42 that directly touches or is exposed to foreign matter floating on the water surface is shortened as much as possible. Is more widely set. This makes it possible to detect oil that is turbid and has a certain thickness, and can be quickly detected when the oil has surfaced. Further, by positioning the water level WL above the float 17a, a stable posture can be maintained as will be described later.

FIG. 6 shows a detailed enlarged view of the fiber sensor 42. As shown in the figure, fiber connectors 43A and 44A are attached to both ends of the fiber sensor 42, and a connector 43B coupled to the connector 43A is provided on the light emitting element 34 side, and the light receiving element 35 side is provided. Is provided with a connector 44B for coupling with the connector 44A. The fiber sensor 42 can be attached to and detached from the light emitting element 34 and the light receiving element 35 via these connectors 43A to 44B.

[0029] Next, the connectors 43A and 44A attached to the end of the fiber sensor 42 will be described. Connectors 43A and 44A include mounting bracket 45, protective tube 46, and female thread 47. The optical fiber core wire 10 is projected from the end by a predetermined length, and a cylindrical mounting bracket 45 is inserted into the fiber sensor 42 and fixed. In order to prevent the fiber sensor 42 from being bent and damaged at the end of the metal fitting 45, a rubber protective tube 46 is covered around the end of the metal fitting 45 located at the longer side of the fiber sensor 42. Attach the female thread 47 to the end of the mounting fixture 45 opposite to the protective tube 46 (that is, the end of the fiber sensor 42). This female thread 47 is free to rotate and can move within a limited range in the axial direction. Engage with mounting bracket 45.

[0030] Connectors 43B and 44B on the light emitting element 34 and light receiving element 35 side are shown in cross section.

Female screws 48 and 48 'are provided at the tips of the connectors 43B and 44B, respectively, and inside the wide holes 49 and 49 ^; for receiving the tips of the metal fittings 45 and narrow holes 50 and 50 for receiving the optical fiber core wire 10, respectively. ^r and are worn in stages. The lid 18b, located on the opposite side of the internal thread 48, 48 ^r, the Semaana 50, 5 (hole 51 for element揷入communicating with T, is provided. The hole 51, 51 / within,. color 52 color 52, 52 ^ is揷入, 52 ^ the outer diameter of, consistent with the inner diameter of the hole 51, 51 ^r, the inner diameter thereof matching the outer diameter of the element 34, 35. its Then, the elements 34 and 35 are inserted into the collars 52 and 52 '. The collars 52 and 52' ¾ are made of an electrically insulating material such as a synthetic resin, and the core for inserting the elements 34 and 35 is inserted. Helps in alignment and electrical insulation.

[0031] When the connectors 43A and 44A are coupled to the connectors 43B and 44B, the optical fiber core wire 10 at the tip of the fiber sensor 42 is inserted into the narrow holes 50 and 50 'as shown by the alternate long and short dash line, and the male screw portion 47 is set to the male screw. Screw on 48, 48 'and tighten until the tip of mounting bracket 45 hits the bottom of wide holes 49, 49'. Then, the distance X between the leading end of the light guide 10 and the leading ends of the light emitting element 34 and the light receiving element 35 in the narrow holes 50 and 50 ′ is set to an ideal distance. In order for the light from the light emitting element 34 to enter the optical fiber core wire 10 effectively, the distance X should not be so large. For example, if the diameter of the optical fiber core wire 10 is 1.2 mm, the distance x is Configure connectors 43Α, 43Β (44Α, 44Β) to be in the range of 0 · 2mm to 0.4 · 4mm.

Furthermore, with reference to FIG. 4 and FIG. 5, the laying state of the float type optical oil detector 17 will be described.

The tip of the rod 60 is rotatably fixed to the float 17a in a hole 57 (see FIG. 3) provided in the guide portion 18e. The other end of the rod 60 is fixed by a wall bracket 63 provided on the side wall of the drainage pit P so that the rotating shaft can rotate in the horizontal direction and perpendicular to the extending direction of the rod 60. ing. As a result, the float 17a moves in the pit P in the height direction following the change in the water level WL (water level WL1 to water level WL2). The rod 60 is made of stainless steel and has three rods 60a, 60b, 60c force S. It is connected to the present.

Further, since the cable 25 is clamped to the rod 60, the cable 25 extending from the float 17a is guided to the rod 60 and connected to the monitoring device 7 through the wall surface bracket 63.

The monitoring device 7 may be connected to a computer as appropriate to perform setting, data collection, and the like.

The present float type optical oil detector 17 configured as described above is used as follows.

The light emitting element 34 is always operated, and light is incident on the fiber sensor 42. The light passes through the fiber sensor 42 exposed in water, is received by the light receiving element 35, and the output of the light receiving element 35 is amplified by the amplifier circuit provided in the substrate 19 and then transmitted to the monitoring device 7 through the cable 25. Then, when oil adheres to the detection range of the fiber sensor 42, the amount of light received by the light receiving element 35 becomes small, so that the signal applied to the monitoring device 7 falls below a predetermined amount. As a result, an alarm signal indicating abnormality is generated in the monitor 7.

Here, when the water level WL changes, the float 17a that floats in the water moves up and down following the water level change, so that the positional relationship between the water surface and the fiber sensor 42 becomes substantially constant.

That is, according to the float type optical oil detector 17 of the present embodiment, since the fiber sensor 42 is provided in the float 17a, the positional relationship between the fiber sensor 42 and the water surface is always constant, and suddenly Even if the water level fluctuates, stable oil leakage detection is possible without increasing or decreasing the light leakage. In addition, additional installation is possible with a small number of installation steps because no special additional work is required for installation in existing water tanks.

[0035] Since the float 17a includes a light emitting element 34, a light receiving element 35 that converts an optical signal into an electric signal, and a substrate 19 that includes an amplifier circuit that amplifies the signal, a fiber as in the conventional case is provided. There is no need to lay the sensor outside the drainage pit P. In other words, it is possible to perform all terminal processing of the fiber sensor 42, which requires special skills, in the manufacturing process at the factory. Therefore, installation work can be performed easily. In addition, when the fiber sensor is extended to the converter 6 as in the prior art, it is necessary to provide the converter 6 within the fiber sensor installation distance (about 20 m). However, in this embodiment, since the light receiving element 35 having the function of the converter 6 and the substrate 19 are built in the float 17a, the installation location is not limited, and within 20 m from the place where oil leakage detection is performed. Oil leakage sensors can be installed in places where it is difficult to install a converter.

The float 17a has a light-emitting element 34, a light-receiving element 35 that converts an optical signal into an electrical signal, and a substrate 19 that includes an amplification circuit that amplifies the signal. Although the installation location will be limited, it is recognized as an intrinsically safe explosion-proof structure when the light-emitting element 34, the light-receiving element 35 and the substrate 19 are accommodated in a metal casing 23 and combined with an explosion-proof barrier. It can be used without limiting the installation location.

[0036] In addition, in the laying state shown in FIGS. 4 and 5, the rod 60 restricts the horizontal operating range of the float 17a, so that the float 17a can be prevented from coming into contact with other devices or walls. it can.

In addition, since the cable 25 is clamped to the rod 60, it is possible to prevent the float 17a from being inclined due to the heavy weight of the cable 25 and maintain the verticality of the float 17a.

In addition, since the lower end of the float 17a having the center of gravity at the lower part is rotatably supported by the rod 60, when the float 17a is tilted, the float 17a is rotated around the lower end and the posture quickly returns. That is, the vertical posture of the float 17a can be held more stably.

[0037] Since the weight balance of the float 17a is set so that the water level WL is slightly below the lid 18b, the joint between the trunk 18a and the lid 18b is always located on the water surface. It becomes a state. Therefore, the possibility of water intrusion into the float 17a is reduced, and the float 17a can be kept in a good waterproof state.

In addition, since the water level WL is located sufficiently above the float 17a and the center of gravity is below the ballast 20, the float 17a can be kept floating in a stable vertical posture. In other words, when the float 17a tilts, it quickly returns to the vertical position due to the action of buoyancy. Furthermore, the float 17a can be set to a vertical posture by changing the fixed position (horizontal position) of the last 20 with respect to the body 18a.

[0038] Further, since the lower portion of the body portion 18a has a spherical curved surface, the fiber sensor 42 can be provided around the casing 18 with an appropriate curvature.

Further, since the body portion 18a is tapered to be narrowed downward, the upper portion receives larger buoyancy. Therefore, the center of gravity can be lowered also by this, and the vertical posture of the float 17a can be stably maintained as described above.

Note that the present invention is not limited to the above embodiment. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. For example, the following modifications can be considered.

(1) In the above embodiment, a single-core optical fiber made of plastic, that is, a force using a plastic fiber as the fiber sensor 42, is replaced with such a plastic fiber and is made of quartz and has a plurality of wires. A silica fiber cable made of a core wire may be used as the fiber sensor 42.

[0040] (2) The shape of the float 17a is not limited to the above embodiment. Any material that can stably maintain a vertical posture is acceptable. However, since the spherical curved surface is provided as shown in the above-described embodiment, it is easy to attach the optical fiber cable with a predetermined curvature or more.

[0041] (3) In the above embodiment, the donut-shaped substrate 19 is accommodated in the casing 18 in a horizontal posture, but instead the substrate 19 may be rectangular and accommodated in a vertical posture. Les.

(4) In the above embodiment, as shown in FIG. 2, force is provided so that the fiber sensor 42 makes one round in the vertical direction with respect to the float 17a. However, the method is not limited to this.

[0043] (5) In the above embodiment, as shown in FIG. 2, the force detection range in which the oil detection range is set to a portion located on one side of the float _{17a in} the fiber sensor 42 is limited to this. It is not something to be done. For example, the float type optical oil detector may be set on both sides or the lower side of the float 17a according to the use conditions. (6) In the above embodiment, the sterilization measures are taken by the copper plate 38, but a silver or titanium plate may be used.

[0045] (7) In the above embodiment, the laying using the rod 60 of the float type optical oil detector 17 has been described. However, the float 17a is connected to the wall bracket 63 using a flexible rope. It's good to stop the float 17a. Also, depending on the installation location, it may be laid in a state of floating in water without being locked to a fixed object.

(8) The float type optical oil detector 17 is not only used in a state where it is floated on the water in the pit. For example, the float 17a is placed on the floor and the oil leaked onto the floor is removed. The case where it detects is considered. In this case, set the detection range below the float 17a to detect oil leaking on the floor of the pit. That is, the float type optical oil detector 17 is characterized by having a structure that floats on water, but the usage state is not limited to the state that it floats on water.

[0047] The present invention is not limited by the foregoing description, but is only limited by the scope of the appended claims.

Industrial applicability

[0048] The present invention is an optical oil detector that detects oil based on a change in the amount of light leakage that occurs when oil adheres to an optical fiber: a float; and the optical flow sensor fixed to the float. The present invention relates to an optical oil detector comprising: Aiba; a light-emitting element that makes light incident on one end of the optical fiber; and a light-receiving element that converts light emitted from the other end of the optical fiber into an electric signal.

According to the optical oil detector of the present invention, the positional relationship between the sensor and the water surface is always constant by adopting a float type sensor, and the amount of light leakage does not increase or decrease even under sudden water level fluctuations. In addition to enabling oil detection, no special additional processing is required for installation in existing water tanks, etc., so an optical oil detector can be additionally installed with little effort.

Claims

The scope of the claims

[1] Optical oil detector:

With float;

An optical fiber fixed to the float;

A light emitting element that makes light incident on one end of the optical fiber;

A light receiving element that converts the light emitted from the other end of the optical fiber into an electrical signal;

An optical oil detector that detects oil based on a change in light leakage caused when oil adheres to the optical fiber.

[2] The optical oil detector according to claim 1,

An optical oil detector in which the light emitting element and the light receiving element are accommodated in the float.

[3] The optical oil detector according to claim 1,

An optical oil detector in which a spherical curved surface is provided on an outer periphery of the float, and an optical fiber is provided along the spherical curved surface.

[4] The optical oil detector according to claim 3,

An optical oil detector, wherein the float is provided with a protrusion protruding outward from the optical fiber.

[5] The optical oil detector according to claim 1,

The float includes, as a casing, a trunk portion having an opening at the top and a lid that seals the opening of the trunk portion in a waterproof state.

The weight balance of the float is set so that when the float floats on water, the water line is set slightly below the joint between the lid and the trunk.

[6] The optical oil detector according to claim 1,

An optical oil detector further comprising sterilization means for sterilizing the optical fiber.

[7] Optical oil detector:

With float; An optical fiber fixed to the float;

A light receiving element that converts light emitted from the other end of the optical fiber into an electrical signal; and a substrate having a circuit that supplies power to the light emitting element and amplifies the output of the light receiving element;

An optical oil detector, which is housed in the float together with the light emitting element, the light receiving element, and the substrate, and includes a metal casing that covers the light emitting element, the light receiving element, and the substrate.

[8] The optical oil detector according to claim 7,

[9] The optical oil detector according to claim 7,

[10] The optical oil detector according to claim 7,

The weight balance of the float is an optical oil detection port that is set such that when the float floats on water, the water line is positioned slightly below the joint between the lid and the body.

[11] The optical oil detector according to claim 7,