Optical fiber temperature monitoring system, and its test machine and test method.

Abstract

This procedure allows for a simple operational check of a system that monitors temperature using optical fibers installed in the target equipment. [Solution] A test machine for a system that monitors temperature using optical fibers laid in a target facility, comprising: a heater that heats an optical fiber cable over a predetermined length; a control circuit that controls the heater; and a power supply that supplies power to the heater.

Description

Technical Field

[0006] , ,

[0001] The present invention relates to an optical fiber temperature monitoring system, its tester, and a test method.

Background Art

[0002] Temperature measurement technology using optical fibers is known. For example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2020-85508) discloses an optical fiber temperature monitoring system that irradiates an optical fiber with optical pulses and measures the temperature based on the returned light.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In order to confirm the operation of the above-described optical fiber temperature monitoring system, it is necessary to heat the optical fiber in units of the resolution of the distribution position (for example, 1 m or more), and spot heating with a dryer or the like is not sufficient. In addition, since the optical fiber is laid over a wide area, a large number of workers are required for operation confirmation.

[0005] Therefore, an object of the present invention is to provide a method capable of easily performing operation confirmation of a system that performs temperature monitoring using an optical fiber laid in target equipment.

Means for Solving the Problems

[0006] To solve the above-described problems, a first aspect of the present invention is a tester for a system that performs temperature monitoring using an optical fiber laid in target equipment, a heater that heats an optical fiber cable over a predetermined length,​A control circuit for controlling the heater, A power supply that provides power to the heater, The present invention provides a test machine for an optical fiber temperature monitoring system, characterized by comprising the following features.

[0007] In the test machine of the optical fiber temperature monitoring system of the present invention, it is preferable to further include a wireless communication device for connecting to a wireless communication network.

[0008] Furthermore, in the test machine for the optical fiber temperature monitoring system of the present invention, it is preferable that the power supply is at least one of an AC power supply and a battery.

[0009] Furthermore, in the test machine for the optical fiber temperature monitoring system of the present invention, it is preferable that the predetermined length is 0.1 to 3.0 m.

[0010] Furthermore, in the test machine for the optical fiber temperature monitoring system of the present invention, it is preferable that the heater gradually heats the optical fiber cable to a set temperature.

[0011] Furthermore, a second aspect of the present invention provides an optical fiber temperature monitoring system including a test machine for the optical fiber temperature monitoring system described above.

[0012] Furthermore, a third aspect of the present invention is: A test method for a system that monitors temperature using optical fibers laid in the target equipment, The procedure for attaching heaters to a predetermined length of fiber optic cable, A procedure for heating the heater to a predetermined temperature, A procedure for injecting light into the end of the optical fiber and receiving the reflected light, The procedure for verifying operation using the received reflected light, The present invention provides a test method for an optical fiber temperature monitoring system, characterized by including the following: [Effects of the Invention]

[0013] According to the present invention, since heating can be performed by a heater over a predetermined length of an optical fiber laid in a target facility, the operation check of the optical fiber temperature monitoring system can be easily carried out.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic diagram of an optical fiber temperature monitoring system 10 according to an embodiment of the present invention. [Figure 2] It is a block diagram showing the functional configuration of the tester 20. [Figure 3] It is a block diagram showing the functional configuration of another tester 20A. [Figure 4] It is a flowchart showing the test procedure of the optical fiber temperature monitoring system 10.

Embodiments for Carrying Out the Invention

[0015] Hereinafter, an embodiment of an optical fiber temperature monitoring system, a tester, and a test method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to these drawings. Further, since the drawings are for conceptually explaining the present invention, dimensions, ratios, or numbers may be exaggerated or simplified as necessary for easy understanding.

[0016] 1. About the optical fiber temperature monitoring system An optical fiber temperature monitoring system 10 (hereinafter simply referred to as system 10) performs temperature monitoring on various facilities 30 by utilizing the temperature characteristics of an optical fiber. There is no particular limitation on the monitoring target, and examples include factory facilities, power cables and pipelines, electrical equipment, tunnels and utility ducts, various conveyors, plant facilities, data centers, warehouses, and the like. There is also no particular limitation on the purpose of monitoring, and examples include fire detection, temperature management, and abnormality detection.

[0017] As shown in FIG. 1, the system 10 includes an optical fiber cable 11, a measuring device 12, a determination unit 13, and an output unit 14. The optical fiber cable 11 and the measuring device 12 constitute a temperature sensor. Also, all or part of the measuring device 12, the determination unit 13, and the output unit 14 may constitute one functional unit.

[0018] The optical fiber cable 11 is laid inside or outside the facility 30 and houses an optical fiber therein. There is no particular limitation on the type of the available optical fiber cable 11, and examples thereof include a high-strength cord, a non-metallic flat type, a type with a built-in SUS tube, a type with a built-in SUS tube with a PE coating, a type with a built-in SUS tube with a PVC coating, and the like.

[0019] There is no particular limitation on the resolution of the distribution position of the optical fiber, and for example, 0.25 to 3.0 m is suitable. There is no particular limitation on the monitoring temperature of the optical fiber, and for example, 0 to 500 °C is suitable. There is no particular limitation on the temperature resolution of the optical fiber, and for example, 0.1 to 1.0 °C is suitable. There is no particular limitation on the material of the optical fiber, and for example, glass and quartz are suitable.

[0020] The type of the optical fiber may be either single mode or multi mode. Also, there is no particular limitation on the fiber length.

[0021] [[ID=二十二]]The measurement method of the optical fiber cable 11 may be a single-end method in which an optical pulse is incident only from one end of the optical fiber cable 11, or a double-end method in which an optical pulse is incident from both ends of the optical fiber cable 11 laid in a loop shape.

[0022] When there are a plurality of monitoring targets in one facility, one optical fiber cable 11 covering the plurality of monitoring targets may be installed, or one optical fiber cable 11 may be installed for each monitoring target. In the latter case, a plurality of optical fiber cables 11 may be connected to one optical switch, and measurement may be performed by sequentially switching a plurality of optical fiber routes from the optical switch.

[0023] A measuring instrument 12 is connected to the optical fiber cable 11 either via an optical switch or directly. The measuring instrument 12 detects reflected light by injecting optical pulses into the optical fiber, and for example, an OTDR (Optical Time Domain Reflectometer) or an optical pulse tester can be suitably used.

[0024] An OTDR includes a light source (such as a semiconductor laser), a photodetector, and a high-precision timing (or time base) circuit. The light source emits pulsed light at a predetermined frequency (time interval), and this pulsed light propagates along an optical fiber. As it travels through the fiber, the emitted light is reflected / refracted or scattered, and returns to the OTDR's photodetector. From the intensity of this returned light (backscattered light) and the time it takes to return to the photodetector, the type and location of events occurring in the optical fiber can be determined.

[0025] In this embodiment, Raman scattered light, which is highly temperature-dependent, may be preferably used among the backscattered light. Raman scattered light consists of anti-Stokes light, which is generated on the shorter wavelength side of the light pulse, and Stokes light, which is generated on the longer wavelength side, and the intensity ratio of these two is proportional to the temperature. The measuring instrument 12 uses this property to measure the temperature of the equipment 30 or its surroundings. Furthermore, the measuring instrument 12 measures the round-trip time from the time pulsed light is incident on the optical fiber until the generated back-Raman scattered light returns to the incident end. From the measured time and the speed of light within the optical fiber, the position (distance) where the scattered light originated can be calculated. The width and pulse interval of the optical pulses may be set appropriately, taking into account the length and type of the optical fiber.

[0026] The measuring instrument 12 may measure the temperature of the equipment 30 at a predetermined period (time interval). The measuring instrument 12 transmits the measured temperature and position data (which may also be the intensity of reflected light and the elapsed time since incidence; hereinafter referred to as "temperature data") to the determination unit 13.

[0027] The determination unit 13 determines whether or not an abnormality has occurred in the equipment 30 and where the abnormality occurred, based on temperature and other data received from the measuring instrument 12. The abnormality in the equipment 30 that the determination unit 13 determines can be any abnormality that can be detected based on temperature changes, but one example is the possibility of a fire occurring in the equipment 30.

[0028] The determination unit 13 can be configured as a computer having, for example, a processor (CPU, etc.), memory (RAM, etc.), storage (ROM, etc.), input devices (keyboard, mouse, touch panel, etc.), and output devices (display, printer, speaker, etc.). Such a computer can realize the function of the determination unit 13 by having the processor read programs and various data stored in the storage into the memory and execute them.

[0029] The determination unit 13 transmits the result of the abnormality determination process in the equipment 30 (hereinafter referred to as the "determination result") to the output unit 14. The determination result may include the location where the abnormality occurred and the measured temperature.

[0030] The output unit 14 outputs the judgment result received from the judgment unit 13. The output unit 14 may be, for example, a display, printer, speaker, etc., and may be included in the computer described above. The output unit 14 may also transmit the judgment result to an external organization responsible for firefighting, security, etc.

[0031] The output unit 14 may output the judgment result periodically or irregularly. The output unit 14 may also output the judgment result at a time requested by the user or administrator (hereinafter simply referred to as "user, etc."). In this case, for example, the output unit 14 may output the judgment result in response to an input operation indicating a request from the user, etc.

[0032] The output unit 14 may notify the user of the system 10 of the judgment result. For example, the output unit 14 may notify the user of the judgment result by displaying it on a display, issuing an alarm, or outputting it to a fire alarm device.

[0033] The output unit 14 may also notify information related to the equipment 30, such as temperature data calculated by the measuring instrument 12, in addition to the determination result from the determination unit 13.

[0034] 2. About the testing machine The test machine 20 is used to verify the operation of the system 10 described above. In other words, when a certain area of ​​the optical fiber cable 11 is heated using the test machine 20, it is checked whether the system 10 operates normally (i.e., whether an abnormality is detected).

[0035] As shown in Figure 2, the test machine 20 may be configured to include a heater 21 that heats the optical fiber cable 11 over a predetermined length, a control circuit 22 that controls the heater 21, and a power supply 23 that supplies power to the heater 21.

[0036] The length of the optical fiber cable 11 heated by the heater 21 is set to be approximately the same as or slightly larger than the resolution of the distribution position of the optical fiber cable 11, preferably 0.1 to 3.0 m, and particularly preferably 1.0 to 3.0 m.

[0037] The heater 21 can take any form as long as it can heat the optical fiber cable 11 over a predetermined length. For example, it may consist of a meandering heating element and a strip of fabric housing the heating element, or it may further include a fastener (e.g., a hook-and-loop fastener) for wrapping around and securing it to the optical fiber cable 11. Alternatively, the heater 21 may be approximately square in shape to heat an optical fiber wound in a roughly circular shape (see Figure 3).

[0038] The heater 21 may be provided with a set temperature, which allows for operational verification under various event scenarios other than fire. There are no particular restrictions on the set temperature, but for example, it may be set to 60-70°C when simulating fire detection. This temperature setting may be performed via an operation button (not shown) on the test machine 20.

[0039] The control circuit 22 may heat the heater 21 to the set temperature all at once (in steps), or it may heat the heater 21 gradually within an allowable time range (for example, 1 minute). By gradually increasing the temperature, the operation of system 10 can be confirmed at multiple temperatures. Furthermore, by gradually heating the heater 21, the temperature characteristics of the temperature sensors constituting system 10 can be determined.

[0040] Power source 23 may consist of at least one of the following: an AC power source or a portable power source. While commercial power can be used as the AC power source, it is not limited to this. Furthermore, by using portable power sources such as primary batteries and secondary batteries, it becomes possible to carry the test equipment 20 to locations where AC power 23 is unavailable and conduct tests.

[0041] The test machine 20 may further include a wireless communication device for connecting to a wireless communication network. Examples of wireless communication devices include, but are not limited to, Wi-Fi (trademark) and BLE (Bluetooth Low Energy). By utilizing the wireless function, the test can be performed even from a distance from the determination unit 13 of the system 10.

[0042] The test machine 20 may also include a display unit 24. The display unit 24 may include a power lamp that lights up when the power supply 23 is turned on, a heater power lamp that lights up when the heater 21 is powered on, a heater setting value display unit that displays the set temperature of the heater 21, and a heater current temperature display unit that displays the current temperature of the heater 21.

[0043] Furthermore, by using multiple test machines 20, it is possible to verify the operation of the system 10 in response to complex events such as simultaneous fires.

[0044] The test machine 20 may be a device independent of the system 10, as shown in Figure 2, or it may be incorporated into the system 10, as shown in the test machine 20A in Figure 3. In Figure 3, a portion of the optical fiber cable 11 is installed in a wound state, and that portion is covered by a planar (approximately square) heater 21. Other functional parts of the test machine 20A may be installed alongside the determination unit 13 of the system 10, or they may be incorporated into the determination unit 13.

[0045] 3. Examination Method Referring to Figure 4, the testing method for system 10 using the test machine 20 will be explained. Here, the testing procedure using the test machine 20 as a standalone device is described, but the test machine 20A incorporated into system 10 can be used in a generally similar manner.

[0046] In step S1, the heater 21 is attached to the optical fiber cable 11. Attaching the heater 21 here includes covering the optical fiber cable 11 with the heater 21, wrapping the heater 21 around the optical fiber cable 11, or sandwiching the optical fiber cable 11 between the heaters 21. The location for attaching the heater 21 may be predetermined, or it may be determined by the worker as appropriate.

[0047] In step S2, the heater 21 is heated to the set temperature. For example, the power supply 23 of the test machine 20 is turned on and the heating switch is turned ON. The heating temperature may be set in advance, or it may be changed as needed while checking the operation of the system 10.

[0048] In addition, in step S3, an optical pulse is injected from the end of the optical fiber. In parallel, in step S4, the operation is checked using reflected light. That is, it is confirmed that the system 10 shows an abnormality. If the abnormal location indicated by the system 10 coincides with the location heated by the heater 21, it is determined that the system 10 is operating normally, and the test is terminated. In other cases, a retest is performed or the system 10 is inspected.

[0049] Although an embodiment of the present invention, including an optical fiber temperature monitoring system, a test machine, and a test method thereof, has been described above, the present invention is not limited to these, and various design modifications are possible as long as they embody the technical concept of the present invention, and all such design modifications fall within the technical scope of the present invention. [Explanation of symbols]

[0050] 10. Optical Fiber Temperature Monitoring System 11 Fiber optic cable 20 Testing Machines 21 Heater 22 Control circuits 23 Power supply 30 Equipment

Claims

1. A test machine for a system that monitors temperature using optical fibers laid in the target equipment, A heater that heats the fiber optic cable over a predetermined length, A control circuit for controlling the heater, A power supply that provides power to the heater, A test machine for an optical fiber temperature monitoring system, characterized by being equipped with the following:

2. The device further comprises a wireless communication device for connecting to a wireless communication network. A test machine for the optical fiber temperature monitoring system according to claim 1, characterized by the above.

3. The power source is at least one of AC power and a battery. A test machine for the optical fiber temperature monitoring system according to claim 1, characterized by the above.

4. The predetermined length is 0.1 to 3.0 m. A test machine for the optical fiber temperature monitoring system according to claim 1, characterized by the above.

5. The heater gradually heats the optical fiber cable to a set temperature. A test machine for the optical fiber temperature monitoring system according to claim 1, characterized by the above.

6. An optical fiber temperature monitoring system including a test machine for the optical fiber temperature monitoring system described in claim 1.

7. A test method for a system that monitors temperature using optical fibers laid in the target equipment, The procedure for attaching heaters to a predetermined length of fiber optic cable, A procedure for heating the heater to a predetermined temperature, A procedure for injecting light into the end of the optical fiber and receiving the reflected light, The procedure for verifying operation using the received reflected light, A test method for an optical fiber temperature monitoring system, characterized by including the following:

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