Cable Tray Inspection Method

Abstract

To detect leakage of a fire-extinguishing agent in a cable tray.SOLUTION: An inspection method for a cable tray fire-extinguishing facility comprises: a cable tray that holds a cable; a sensing tube that is provided in the cable tray and melted by heat of a fire, and has a fire-extinguishing agent inside; an open type injection nozzle that is provided in the cable tray and discharges the fire-extinguishing agent; a covering member that covers the cable tray; and a pipe capable of supplying the fire-extinguishing agent to the injection nozzle. The method includes the steps of: sucking the fire-extinguishing agent in the cable tray through the pipe and the injection nozzle; and analyzing the sucked fire-extinguishing agent to detect leakage of the fire-extinguishing agent.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for inspecting a cable tray. [Background technology]

[0002] A conventional cable tray is disclosed in, for example, Japanese Patent Laid-Open Publication No. 2022-48318 (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-48318 Summary of the Invention [Problem to be solved by the invention]

[0004] With conventional cable trays, it is difficult to detect leaks of fire extinguishing agents. [Means for solving the problem]

[0005] The inspection method for cable trays is as follows: a cable tray for holding cables; a sensing tube provided in the cable tray and melting due to the heat of a fire, the sensing tube having a fire extinguishing agent therein; an open-type injection nozzle provided in the cable tray for discharging a fire extinguishing agent; a covering member that covers the cable tray; and a piping capable of supplying a fire extinguishing agent to the injection nozzle, sucking gas from within the cable tray through the piping and the injection nozzle; and analyzing the aspirated gas to detect a leak of the fire extinguishing agent.

[0006] In the cable tray inspection method including these steps, the fire extinguishing agent in the cable tray can be sucked out using a conventional open-type spray nozzle and piping, and as a result, the fire extinguishing agent in the cable tray can be analyzed and inspected for leaks without disassembling the cable tray.

[0007] Preferably, the step of detecting a leak of the extinguishing agent includes irradiating the sucked gas with laser light and detecting the leak of the extinguishing agent based on the Raman scattering wavelength of a peak characteristic specific to the extinguishing agent.

[0008] In this case, the peak of the Raman scattering wavelength is sufficiently large that it is possible to reliably detect the leak of the fire extinguishing agent. Note that fire extinguishing agents can be detected not only by resonance Raman scattering but also by simple Raman scattering, depending on their concentrations.

[0009] Preferably, the extinguishing agent comprises CF3CF2C(O)CF(CF3)2. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram of a cable tray fire extinguishing system 60 according to a first embodiment. [Figure 2] 1 is a front view of a container support 20 according to a first embodiment. [Figure 3] 1 is a diagram showing an inspection method for a cable tray fire extinguishing system 60 according to the first embodiment. [Figure 4] 1 is a schematic diagram showing a process of gas analysis using an optical gas sensor 101. FIG. [Figure 5] 1 is a graph showing the characteristics of a fire extinguishing agent (FK-5-1-12), and a graph showing a resonance Raman spectrum. [Figure 6] FIG. 10 shows a method and apparatus for measuring extinguishing agent leakage using a remote measurement device 201 according to a second embodiment. [Figure 7] FIG. 10 is a diagram showing a method and apparatus for measuring leakage of fire extinguishing agent from a multi-stage cable tray 31 using a remote measurement device 201 according to a second embodiment. [Figure 8] FIG. 10 is a block diagram showing a configuration of a remote measurement device 201 according to a second embodiment. [Figure 9] FIG. 3 is a diagram of a measurement device 300 for a resonance Raman spectrum using a wavelength-tunable laser beam. [Figure 10] This is resonance Raman spectrum data obtained when sample 1 is irradiated with laser light 311 having a wavelength of 210 nm and an energy of 1 mJ. [Figure 11] This is resonance Raman spectrum data obtained when sample 2 is irradiated with laser light 311 having a wavelength of 210 nm and an energy of 1 mJ. [Figure 12] This is resonance Raman spectrum data obtained when sample 1 is irradiated with laser light 311 having a wavelength of 266 nm and an energy of 3 mJ. [Figure 13] This is resonance Raman spectrum data obtained when sample 2 is irradiated with laser light 311 having a wavelength of 266 nm and an energy of 3 mJ. [Figure 14] FIG. 4 is a diagram of an apparatus 400 for measuring a resonance Raman spectrum using laser light in an open system. [Figure 15] 10 is a graph showing the relationship between the distance from the measurement device 400 and the signal strength in an open system. [Figure 16] This is resonance Raman spectrum data obtained when a fire extinguishing agent (FK-5-1-12) gas is irradiated with laser light having a wavelength of 210 nm. [Figure 17] This is resonance Raman spectrum data obtained when a fire extinguishing agent (FK-5-1-12) gas is irradiated with laser light having a wavelength of 225 nm. [Figure 18] This is resonance Raman spectrum data obtained when a fire extinguishing agent (FK-5-1-12) gas is irradiated with laser light having a wavelength of 250 nm. [Figure 19] This is resonance Raman spectrum data obtained when a fire extinguishing agent (FK-5-1-12) gas is irradiated with laser light having a wavelength of 266 nm. [Figure 20]This is resonance Raman spectrum data obtained when a fire extinguishing agent (FK-5-1-12) gas is irradiated with laser light having a wavelength of 278 nm. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described with reference to the drawings. The same or corresponding parts will be designated by the same reference characters, and description thereof will not be repeated.

[0012] (Embodiment 1) Fig. 1 is a schematic diagram of a cable tray fire extinguishing system 60 according to embodiment 1. As shown in Fig. 1, in the cable tray fire extinguishing system 60 according to embodiment 1, a container valve 19 is attached to the top of a fire extinguishing agent storage container 1. The fire extinguishing agent storage container 1 is supported by a container support body 15.

[0013] Connected to the container valve 19 are a copper pipe 25 for discharging the fire extinguishing agent, a sensing tube 24, a pressure switch 4 for the sensing tube, and a pressure switch 3 for the storage container. The pressure switch 4 for the sensing tube does not necessarily have to be connected directly to the container valve 19, but may be connected somewhere along the sensing tube 24 (near the pressure gauge). The pressure switch 4 for the sensing tube and the pressure switch 3 for the storage container do not have to be connected to the container valve 19.

[0014] The inside of the sensing tube 24 is constantly pressurized. The sensing tube 24 extends into a cable tray 31. The cable tray 31 is installed in factories, buildings, power plants, etc. The cable tray 31 is cylindrical, and a cable is installed inside it. The cable tray 31 is covered with a flame-retardant sheet 32 as a covering member. The flame-retardant sheet 32 is fixed to the cable tray 31 by a fixing band 33. A stainless steel band is wrapped around the cable tray 31 in the same position as the fixing band 33, preventing the flame-retardant sheet 32 from sagging into the cable tray 31.

[0015] A sensing tube 24 is provided within the cable tray 31. The sensing tube 24 may or may not be in contact with the cable. A copper pipe 25 for discharging a fire extinguishing agent is provided within the cable tray 31. An open-type spray nozzle 34 for discharging a fire extinguishing agent is attached to the copper pipe 25 for discharging a fire extinguishing agent.

[0016] Fire extinguishing agent storage container 1 contains, for example, the halogenated fire extinguishing agent FK-5-1-12 as the fire extinguishing agent. This agent is pressurized by nitrogen inside fire extinguishing agent storage container 1. This nitrogen is supplied to sensing tube 24 via sensing tube pressure switch 4. When installing, if nitrogen is supplied into sensing tube 24 from fire extinguishing agent storage container 1, the amount of nitrogen inside fire extinguishing agent storage container 1 will decrease. Therefore, nitrogen may be filled into sensing tube 24 from outside fire extinguishing agent storage container 1.

[0017] When the heat of the fire melts the sensing tube 24, the pressure inside the sensing tube 24 drops.

[0018] When the pressure in the sensing tube 24 drops, the container valve 19 operates, and the extinguishing agent (FK-5-1-12) is discharged from the extinguishing agent discharge nozzle 34 in the cable tray 31 through the extinguishing agent discharge copper pipe 25.

[0019] When the pressure inside the sensing tube 24 drops, the sensing tube pressure switch 4 is activated and a signal is sent out.

[0020] When the pressure inside the fire extinguishing agent storage container 1 drops, the storage container pressure switch 3 is activated and a signal is sent out.

[0021] The cable tray 31 is often installed near the ceiling of the building, and because it is located at a high altitude, it cannot be inspected without preparing scaffolding, making inspection work extremely labor-intensive.

[0022] The inside of the cable tray 31 is an enclosed space, and a flame-retardant sheet 32 is wrapped around it to prevent the spread of fire and to keep the fire extinguishing agent (FK-5-1-12) inside the cable tray 31, so it is not possible to visually check inside the cable tray 31.

[0023] FIG. 2 is a front view of the container support 20 according to the first embodiment.

[0024] The container support body 15 is mainly made of steel square pipes and angle bars. The container support body 15 is made by welding steel materials. It has sufficient strength to hold multiple fire extinguishant storage containers 1.

[0025] The fire extinguishant storage container 1, which is constituted by a cylinder, stores a liquid fire extinguishant such as FK-5-1-12. In this embodiment, three fire extinguishant storage containers 1 are provided in parallel, but more or fewer fire extinguishant storage containers 1 may be provided.

[0026] The container valve 19 of the fire extinguishant storage container 1 is connected to the copper pipe connection joint 6 by a flexible tube 2. As a result, the fire extinguishant in the fire extinguishant storage container 1 is supplied to the copper pipe connection joint 6 via the flexible tube 2.

[0027] The pressure inside the fire extinguishing agent storage container 1 is constantly monitored, and when this pressure drops, the storage container pressure switch 3 is activated and a signal is sent to a monitoring room or the like.

[0028] The pressure inside the sensing tube 24 is constantly monitored, and when this pressure drops, the sensing tube pressure switch 4 is activated and a signal is sent to a monitoring room or the like.

[0029] Based on these communication signals, a person in a monitoring room or the like can recognize that a fire has occurred.

[0030] The container fixing bracket 5 engages with the container support body 15 to hold the fire extinguishant storage container 1. A thread is provided on the outer peripheral surface of the end of the container fixing bracket 5, and the container fixing bracket 5 can be fixed to the container support body 15 by screwing a nut onto this thread.

[0031] The copper pipe connection joint 6 is attached to the container support body 15. The copper pipe connection joint 6 is interposed between the flexible tube 2 and the extinguishing agent discharge copper pipe 25 and is airtightly connected to them. The extinguishing agent flows through the copper pipe connection joint 6.

[0032] A sensing tube 24 is connected to the sensing tube filling joint 11. Nitrogen is supplied to the sensing tube filling joint 11 from the fire extinguishing agent storage container 1. The sensing tube filling joint 11 is attached to the container support body 15.

[0033] 3 is a diagram showing a method for inspecting the cable tray fire extinguishing system 60 according to the first embodiment. As shown in FIG. 3, during inspection, a flexible pipe 103 is connected to the extinguishant discharge copper pipe 25. An optical gas sensor 101 and a suction pump 102 are connected to the flexible pipe 103. By driving the suction pump 102, gas inside the cable tray 31 is sucked in via the extinguishant discharge copper pipe 25 and the open-type extinguishant discharge jet nozzle 34.

[0034] If extinguishing agent leaks from the sensing tube 24 into the cable tray 31, the leaked extinguishing agent is sucked in through the extinguishing agent discharge nozzle 34 and reaches the optical gas sensor 101 serving as an analyzer.

[0035] 4 is a schematic diagram showing the process of gas analysis using an optical gas sensor 101. The optical gas sensor 101 may be, for example, a measurement visualization device described in Japanese Patent Application Laid-Open No. 2013-167497. The optical gas sensor 101 measures whether CFCFC(O)CF(CF) (FK-5-1-12: NOVEC (registered trademark) 1230) contained in the fire extinguishing agent is contained in the drawn-in gas.

[0036] The optical gas sensor 101 is an optical gas sensor that uses the Raman scattering method. As shown in Fig. 4, the optical gas sensor 101 includes a gas detection unit 110, an incident-side optical fiber 120 connected to the gas detection unit 110, and a receiving-side optical fiber 130.

[0037] One end of the incident optical fiber 120 is connected to a monochromatic light source such as a laser or a high-intensity LED, and guides light from the light source to the gas detection unit 110 as indicated by arrow 182. One end of the receiving optical fiber 130 is connected to a photodetector such as a photomultiplier tube, an avalanche photodiode, a phototransistor, or a CCD, and guides Raman scattered light generated in the gas detection unit 110 to the photodetector as indicated by arrow 183. An analog-to-digital converter (ADC), a computer, or the like is connected to the photodetector. The type and concentration of gas present in the gas detection unit 110 can be calculated from the detection signal of the photodetector using a known method. For example, an interference filter can be inserted between the receiving optical fiber 130 and the photodetector, and the concentration of the target gas can be measured by selecting the Raman scattered light corresponding to the target gas using the interference filter. The type of gas present in the gas detection unit 110 can be identified by replacing the interference filter.

[0038] The gas detection unit 110 is a part that is directly exposed to the gas to be measured, and corresponds to a so-called probe that is fixed at a location where the gas is to be measured (measurement position), such as inside a pipe. The gas detection unit 110, the light source, and the photodetector are connected by an incident-side optical fiber 120 and a receiving-side optical fiber 130, so that only the gas detection unit 110 is fixed at the measurement position, and other devices such as the light source and the photodetector can be installed at locations away from the measurement position.

[0039] The gas detection unit 110 is composed of a compact optical bench 111, an incident-side microlens 112, and a light-receiving-side microlens 113. The compact optical bench 111 is a flat plate member having dimensions of several mm to several tens of mm square.

[0040] A ferrule 121 is fixed to the tip of the incident-side optical fiber 120. A ferrule 131 is fixed to the tip of the receiving-side optical fiber 130. The compact optical bench 111 has a micromirror 118 formed integrally therewith.

[0041] The Raman scattering phenomenon is a phenomenon in which, when light is irradiated onto a substance such as a gas, the wavelength of some of the scattered light changes due to the molecular vibration and rotation of the substance. This scattered light is called Raman scattered light. It is also known that the wavelength of Raman scattered light varies depending on the molecular species (gas species in gases, bound molecular species in liquids), and there is a correlation between the gas concentration and the intensity of Raman scattered light. Therefore, the gas species can be identified from the Raman scattered light wavelength, and the gas concentration can be identified from the Raman scattered light intensity. Furthermore, when the laser wavelength matches the resonant excitation wavelength specific to the substance, the resonance effect generates Raman scattered light (hereinafter sometimes referred to as "resonant Raman scattered light") that is significantly more intense than normal Raman scattered light.

[0042] The gas detection unit 110 in this embodiment is configured with a Raman scattering optical system that causes laser light emitted from the tip of the incident-side optical fiber 120 to be incident on the gas to be measured, and causes Raman scattered light emitted by the interaction between the laser light and the gas to be measured to be incident on the tip of the receiving-side optical fiber 130.

[0043] The following shows an example of parameters for measuring a fire extinguishing agent gas. The Raman scattering optical system configured in the gas detection unit 110 of the optical gas sensor 101 used in the test was set so that the angle α between the optical axis of the incident-side optical fiber 120 and the normal to the reflecting surface of the micromirror 118 was 8.6°, the angle β between the optical axis of the incident-side optical fiber 120 and the optical axis of the light-receiving-side optical fiber 130 was 151.9°, the distance between the incident-side microlens 112 and the micromirror 118 on the optical axis of the incident-side optical fiber 120 was 20.0 mm, and the distance between the receiving-side microlens 113 and the optical axis of the incident-side optical fiber 120 on the optical axis of the light-receiving-side optical fiber 130 was 9.55 mm. Furthermore, second-harmonic laser light from an Nd:YAG laser (Explorer, manufactured by Spectra-Physics) with an oscillation wavelength of 532 nm was used as the light source connected to the incident-side optical fiber 120, and a photomultiplier tube (R3896, manufactured by Hamamatsu Photonics KK) was used as the photodetector connected to the light-receiving-side optical fiber 130. Then, gas was introduced into the gas detection unit 110 from the flexible pipe 103, and the signal intensity obtained by the photodetector was measured.

[0044] In this embodiment, the extinguishing agent gas is analyzed using Raman scattered light from the extinguishing agent gas that is the irradiated object, but the extinguishing agent gas may also be analyzed by other methods, for example, ultraviolet absorption spectroscopy.

[0045] Furthermore, although an example has been given in which CF3CF2C(O)CF(CF3)2, which constitutes FK-5-1-12 (product name: Novec (registered trademark) 1230) contained in the gas, is analyzed, other gases, such as halon gas, may also be analyzed.

[0046] In the analysis method configured as described above, the gas inside the cable tray 31 is sucked in via the open-type extinguishant discharge jet nozzle 34 and the extinguishant discharge copper pipe 25, and the gas is analyzed to detect extinguishant leaks, so it is possible to make maximum use of existing equipment and detect extinguishant leaks inside the cable tray 31 with high accuracy. Therefore, it is possible to inspect for extinguishant leaks inside the cable tray 31 while minimizing the addition of new equipment.

[0047] (Embodiment 2) Fig. 5 is a graph showing the characteristics of a fire extinguishing agent (FK-5-1-12), and is a graph showing a resonance Raman spectrum. Fig. 6 is a diagram showing a method and apparatus for measuring a leakage of a fire extinguishing agent using a remote measurement device 201 according to a second embodiment.

[0048] In the second embodiment, the resonance Raman spectrum of the extinguishing agent is used to measure the concentration of the extinguishing agent present at a distance, and to measure leakage of the extinguishing agent from piping, tubes, and the like.

[0049] As shown in Figure 5, ultraviolet light with a wavelength of 266 nm is used as the incident light for the fire extinguishing agent. Taking into consideration the results of preliminary experiments and the versatility of the laser device, 266 nm was selected from the resonance wavelength range.

[0050] As shown in Figure 5, the areas indicated by A1 to A3 show the peaks of the resonance Raman spectrum of the fire extinguishing agent gas. Among these, the peak A1 with the highest light intensity is 754.6 cm -1 When converted to wavelength, 271.4 nm was adopted as the observation wavelength.

[0051] As shown in Figure 6, the worker 152 is holding a handheld remote measurement device 201. The remote measurement device 201 locates the presence of a fire extinguishing agent (FK-5-1-12). Specifically, it identifies the type of substance and locates its location by capturing the Raman scattered light (Figure 5) emitted from the fire extinguishing agent. By scanning with a laser beam, it is possible to capture the spatial distribution of the target gas in three dimensions. This makes it possible to detect fire extinguishing agent leaking from the joint of the sensing tube 24 outside the cable tray 31 or from gaps in the fire prevention sheet of the cable tray 31, and to identify the location of the leak.

[0052] Worker 152 holds a handheld remote measurement device 201. A laser beam is emitted from remote measurement device 201 in the direction indicated by arrow 202. The laser beam emitted from remote measurement device 201 is irradiated onto metal duct 151 for fixing sensing tube 24, the sensing tube 24 in the portion where metal duct 151 is not present, and cable tray 31. Remote measurement device 201 receives the generated Raman scattered light (resonance Raman spectrum: FIG. 5), and from the information on the received light, it is possible to determine whether or not a fire extinguishing agent is leaking in the irradiated portion.

[0053] Unlike the first embodiment, the remote measurement device 201 according to the second embodiment does not require the extinguishing agent in the cable tray 31 to be moved close to the remote measurement device 201. Therefore, it is possible to detect a leak of extinguishing agent in a place that is difficult to access.

[0054] 7 is a diagram showing a method and device for measuring leakage of extinguishing agent from multiple tiers of cable trays 31 using remote measurement device 201 according to the second embodiment. As shown in FIG. 7, when multiple tiers of cable trays 31 are stacked, remote measurement device 201 is attached to extension device 155 that extends upward from the ground. This allows remote measurement device 201 to be brought close to the cable tray 31 of the tier to be measured. As a result, remote measurement device 201 can be brought close to the gaps between each cable tray 31, making it possible to measure leakage of extinguishing agent from the cable tray 31 of each tier.

[0055] Fig. 8 is a block diagram showing the configuration of a remote measurement device 201 according to embodiment 2. As shown in Fig. 8, the remote measurement device 201 according to this embodiment includes a laser device 210, a telescope 220, a spectroscopic optical system 230, a photodetector 240, total reflection mirrors 251 and 252, and a processing device 260. This device has a configuration similar to that described in Japanese Patent No. 7231971.

[0056] The laser device 210 has an oscillator 211 which is a laser light source. As in this embodiment, the laser device 210 can be configured to include a harmonic generator 212 as needed, and to convert the laser light oscillated by the oscillator 211 into a harmonic (for example, a fifth harmonic) and emit it to the outside. The emitted laser light is emitted into the irradiated space 270 via total reflection mirrors 251 and 252.

[0057] The type of laser device 210 is not particularly limited, but a solid-state laser is preferred. A typical solid-state laser is configured to excite a laser medium placed within an optical resonator (e.g., two reflecting mirrors) by applying optical energy from an excitation light source (e.g., a flash lamp). The laser medium is solid, and a solid-state laser having a laser medium made of a crystalline material, such as glass or ceramics such as ytterbium aluminum garnet (YAG), doped with neodymium or yttrium (Yb), can be used. A more preferred laser is a semiconductor-pumped solid-state laser (DPSS-L) that uses laser light output from a semiconductor laser as excitation light. This laser is capable of short-pulse oscillation of 3 ns or less (preferably 2 ns or less, more preferably 1 ns or less), whereas solid-state lasers have pulse widths of approximately 5 to 10 ns. For example, the microchip-type DPSS-L of this embodiment includes a semiconductor laser, a collimating lens, a laser crystal with an HR coating, a saturable absorber, an output mirror, and an SHG crystal. It is a device that significantly reduces the size of a solid-state laser while maintaining a constant output power. Examples of microchip type DPSS-L laser crystals include Nd:YAG, Nd:YLF, Nd:glass, Nd:YVO4, Yb:YAG, and Nd:GVO.

[0058] The microchip type DPSS-L (microchip laser) is compact yet capable of highly efficient excitation because the semiconductor laser's oscillation wavelength is set to a band that efficiently interacts with the laser crystal. It also uses extremely small laser crystals, on the order of a few millimeters, and a reflective coating (HR coating) is applied to one end of the laser crystal, allowing the laser crystal itself to function as a resonator mirror. Furthermore, a crystal called a saturable absorber, which becomes transparent when a certain amount of energy is accumulated, is used to provide the Q-switch function. The microchip type DPSS-L achieves compactness and robustness by monolithically integrating these crystals and optical elements.

[0059] In this way, by using a microchip laser, which is an ultra-compact pulse laser, as the oscillator 211 of the laser device 210, it is possible to reduce the size of the laser device 210 or the entire remote measurement device 201 and increase its robustness. Also, some microchip lasers are integrated with the harmonic generator 212, such as a microchip laser that emits the fifth harmonic of Nd:YAG.

[0060] In this embodiment, the laser device 210 irradiates the irradiated space with pulsed laser light to excite the fire extinguishing agent and generate resonant Raman scattered light caused by the fire extinguishing agent. By irradiating the laser light in pulses, the distance between the light detection device 240 and the fire extinguishing agent can be determined from the time of laser light irradiation and the time of detection of the resonant Raman scattered light.

[0061] In addition, when a laser device is to identify multiple substances, it needs to be equipped with a mechanism that can switch and irradiate excitation wavelengths appropriate for each substance. However, since the remote measurement device 201 of this embodiment measures fire extinguishing agents, the laser device 210 can be configured to irradiate only laser light with a single excitation wavelength of 266 nm.

[0062] Laser light emitted from laser device 210 in the direction indicated by arrow 202 is reflected by total reflection mirrors 251 and 252 and irradiated into irradiated space 270. Raman scattered light or resonant Raman scattered light from irradiated space 270 travels in the direction indicated by arrow 203 and reaches telescope 220.

[0063] The telescope 220 is composed of multiple optical systems and focuses Raman scattered light and resonance Raman scattered light incident from the irradiated space 270. In this embodiment, deep-ultraviolet laser light emitted from the laser device 210 collides with a fire extinguishing agent or the like in the irradiated space 270, generating Raman scattered light and resonance Raman scattered light. A portion of the Raman scattered light and resonance Raman scattered light generated in the irradiated space 270 enters the telescope 220 along with visible light and the like. Note that, in order to receive resonance Raman scattered light caused by the fire extinguishing agent and exclude other light components as much as possible, it is preferable to use a deep-ultraviolet telescope that focuses light in the ultraviolet range around a wavelength of 271.4 nm as the telescope 220. Furthermore, in such a deep-ultraviolet telescope, it is preferable that all optical systems collect light in the deep-ultraviolet range with high efficiency, and a reflective type is preferable from the standpoints of efficiency and aberration.

[0064] The spectroscopic optical system 230 is a spectrometer or a combination of a long-pass filter and a band-pass filter, and separates light in the 271.4 nm wavelength range, which includes resonant Raman scattered light caused by the fire extinguishing agent, from the light that has passed through the telescope 220. By separating only the deep ultraviolet wavelength of 271.4 nm in the spectroscopic optical system 230, the influence of background light can be reduced.

[0065] The photodetector 240 is an ICCD detector, a photomultiplier tube, an APD (avalanche photodiode), or the like, and receives light in the 271.4 nm wavelength range dispersed by the spectroscopic optical system 230, and detects a received light signal with an intensity corresponding to the intensity of the received light. The photodetector 240 is preferably provided with a gate that opens and closes the light reception in synchronization with the irradiation pulse of the laser light, and is configured to receive only the light during the time period when resonant Raman scattered light is emitted (the time period when the laser light is applied) by the opening and closing operation of the gate.

[0066] The processing device 260 calculates the distance from the remote measurement device 201 to the fire-extinguishing agent from the return time of the Raman scattered light or the resonance Raman scattered light. The remote measurement device 201 also has a scanning device that can change the direction of laser light irradiation (the orientation of the laser device 210) and the direction of light reception by the light detection device 240 (the orientation of the light detection device 240), and can measure the spatial distribution of the fire-extinguishing agent by scanning the light emitted from the laser device 210 vertically and horizontally or horizontally and tiltingly within the irradiated space 270 based on a control command from the processing device 260. The remote measurement device 201 can measure the three-dimensional distribution of the fire-extinguishing agent within a range with a radius of, for example, 15 meters from the remote measurement device 201 by detecting the resonance Raman scattered light caused by the fire-extinguishing agent while gradually changing the angles of the direction of laser light irradiation and the direction of light reception of the resonance Raman scattered light.

[0067] Since the irradiated space 270, which is an open space, contains a large amount of atmospheric components such as oxygen, nitrogen, and water vapor, even when laser light with an excitation wavelength for exciting the fire extinguishing agent is irradiated into the irradiated space where the fire extinguishing agent is present, Raman scattered light caused by the atmospheric components is also generated and received by the photodetector 240. However, since the Raman shift of the Raman scattered light caused by the atmospheric components does not overlap with the Raman shift of the resonant Raman scattered light caused by the fire extinguishing agent, the photodetector 240 can detect the received light signal of the resonant Raman scattered light caused by the fire extinguishing agent even in the atmosphere without being interfered with by the Raman scattered light caused by the atmospheric components. For example, when a 266 nm laser light is irradiated, the Raman shift of the Raman scattered light caused by oxygen is 1556 cm -1 The Raman shift of the Raman scattering light caused by nitrogen is 2331 cm -1 The Raman shift of the Raman scattering light caused by water vapor is 3652 cm -1 The Raman shift of the resonance Raman scattering light caused by the fire extinguishing agent is 754.6 cm, which has the highest light intensity. -1 By detecting the light receiving signal at (271.4 nm, A1 in Figure 5), it becomes possible to separate the fire extinguishing agent from atmospheric components and detect it even in the atmosphere.

[0068] In particular, the photodetector 240 detects a wavelength of 2000 cm where the signal strength of the received light signal is particularly high. -1 The signal intensity at the following Raman shift is to be detected. In this embodiment, -1 The received signal was detected at the Raman shift of .

[0069] (Resonance Raman spectra at wavelengths of 210 nm and 266 nm in a closed system) 9 is a diagram of a measurement apparatus 300 for resonance Raman spectra using a wavelength-tunable laser beam. In the measurement apparatus 300, a laser beam 311 is emitted from a tunable laser source 301. The laser beam 311 is reflected by a mirror 302. The laser beam 311 passes through a gas cell 306. A fire-extinguishing agent gas is sealed in the gas cell 306. Resonance Raman scattered light 312 is emitted from the fire-extinguishing agent gas. The resonance Raman scattered light 312 passes through a long-pass filter 305 and a convex lens 304, and enters a high-sensitivity spectrometer 303.

[0070] Samples 1 and 2 using FK-5-1-12 gas were sealed in gas cells, and the resonant Raman spectrum data when the laser light 311 wavelength was 210 nm with 1 mJ of energy and the wavelength was 266 nm with 3 mJ of energy are shown in Figures 10 to 13. In Figures 10 to 13, the peaks indicated by A11 to A15 and A21 to A23 are due to FK-5-1-12 (note that the number of detectable peaks varies depending on factors such as the signal-to-noise ratio). This indicates that FK-5-1-12 was successfully detected. In other words, it was confirmed that in the process of detecting leaks of the fire extinguishing agent FK-5-1-12, it is possible to detect leaks by irradiating the device with laser light and receiving the resonant Raman scattering wavelength with peak characteristics specific to the fire extinguishing agent.

[0071] (Resonance Raman spectrum in an open system) Figure 14 is a diagram of a measurement device 400 for resonance Raman spectra using laser light in an open system. In an open space, an FK-5-1-12 gas discharge system 406 was installed 7 meters away from measurement device 400, a remote measurement device for a fire extinguishing agent (FK-5-1-12). FK-5-1-12 was released into the atmosphere from discharge system 406. A valve and Teflon (registered trademark) tube were connected to bottle 407 containing liquid FK-5-1-12, and the system was designed so that vaporized FK-5-1-12 would be released into the atmosphere at room temperature.

[0072] Laser light 411 with a wavelength of 266 nm and a pulse energy of 1 mJ was emitted from laser device 404 of the remote measurement device in the direction indicated by the arrow, reflected by total reflection mirror 405, and irradiated onto the measurement point (irradiated space) of emission system 406. In addition to irradiating the laser light, resonant Raman scattered light 412 incident from the irradiated space was collected by telescope 403, and resonant Raman scattered light caused by FK-5-1-12 and Raman scattered light caused by the atmosphere incident from the irradiated space were received by photodetector 401. From these, the received light signal of the resonant Raman scattered light caused by FK-5-1-12 was detected, and the signal intensity of the received light signal was measured.

[0073] To detect the resonant Raman scattering light caused by FK-5-1-12, the measurement device 400 is equipped with a filter 402 that includes an edge filter that passes light with wavelengths of 266 nm or longer, and a bandpass filter that extracts the resonant Raman scattering light of FK-5-1-12 with a center wavelength of 271.4 nm and a full width at half maximum of 10 nm. The measured time data was averaged 750 times to calculate the results. One measurement takes approximately 1 second.

[0074] Measurement conditions: Distance: 7 m, Liquid FK-5-1-12 vaporized at room temperature, Averaging times: 750, Observation wavelength: 271.4 nm (Raman shift = 754.6 cm -1 ) From Figure 15, the presence of FK-5-1-12 gas was detected at a distance of 7 m.

[0075] (Raman shifts for various excitation wavelengths in a closed system) Using the apparatus shown in Figure 9, the Raman shift of the fire extinguishing gas FK-5-1-12 was investigated at excitation wavelengths of 210 nm, 225 nm, 250 nm, 266 nm, and 278 nm. As a result, the Raman shift was 760.4 cm at each wavelength. -1 , 1250.6cm -1 and 1780.7 cm -1 The Raman shift of the nitrogen Raman spectrum was confirmed. Detailed resonance Raman spectrum data is shown in Figures 16 to 20. The peaks indicated by "A" in Figures 16 to 20 are derived from FK-5-1-12. The nitrogen Raman light intensity is normalized to 1000 counts.

[0076] This enabled the detection of the fire extinguishing agent gas FK-5-1-12 at various excitation wavelengths.

[0077] According to the present disclosure, 2000 cm -1 or less, preferably 1800 cm -1 The Raman shift of , more specifically, 1780.7 cm -1 The received light signals can be detected at the following Raman shifts (resonance Raman scattering wavelengths):

[0078] Appendix 1 A remote measurement device for fire extinguishing agents that measures the fire extinguishing agent present in an irradiated space, a laser device that emits laser light into the irradiated space, causing the fire extinguishing agent to generate resonant Raman scattered light; a light detection device that receives resonant Raman scattered light from the irradiated space due to the fire extinguishing agent; a processing device that controls the operations of the laser device and the light detection device and detects the fire extinguishing agent present in the irradiated space based on a signal from the light detection device, The photodetector is 2000 cm -1 A remote measurement device for fire extinguishing agents that detects received light signals at the following Raman shifts:

[0079] Appendix 2 the laser device irradiates the laser light into the irradiation space, which is an open space; The remote measurement device for a fire extinguishing agent described in Appendix 1, wherein the processing device detects resonant Raman scattered light caused by the fire extinguishing agent that enters from the irradiated space in an open space.

[0080] Appendix 3 The remote measurement device for a fire extinguishing agent described in Appendix 1, wherein the laser device comprises an oscillator that emits laser light of a specific wavelength and a harmonic generator that converts the specific wavelength into a harmonic with which the fire extinguishing agent resonates.

[0081] Appendix 4 the oscillator is a microchip laser that emits laser light of a single excitation wavelength into an irradiated space, 4. The fire extinguishing agent remote metering device of claim 3, wherein the harmonic generator is a single harmonic generator.

[0082] Appendix 5 4. The remote measurement device for a fire extinguishing agent according to claim 3, wherein the oscillator is a microchip laser that emits laser light having a pulse width of 3 ns or less into the irradiated space.

[0083] Appendix 6 the light detection device also receives Raman scattered light resulting from the fire extinguishing agent from the irradiated space, The remote measurement device for a fire extinguishing agent described in Appendix 1, wherein the processing device measures the concentration of the fire extinguishing agent based on the resonant Raman scattered light caused by the fire extinguishing agent when the concentration of the fire extinguishing agent present in the irradiated space is less than a predetermined value, and measures the concentration of the fire extinguishing agent based on the Raman scattered light caused by the fire extinguishing agent when the concentration is equal to or greater than the predetermined value.

[0084] Appendix 7 The photodetector is 760.4 cm -1 7. A remote measurement device for a fire extinguishing agent according to any one of claims 1 to 6, which detects a received light signal at a Raman shift of

[0085] Appendix 8 A method for remotely measuring a fire extinguishing agent that measures a fire extinguishing agent present in an irradiated space, comprising: a step of emitting laser light from a laser device into the irradiated space, the laser light causing the fire extinguishing agent to generate resonant Raman scattered light; The photodetector detects the 2000cm radius of the extinguishing agent from the irradiated space. -1 detecting the fire extinguishing agent by receiving resonant Raman scattered light at a Raman shift of: and detecting a fire extinguishing agent present in the irradiated space at a concentration of 100 ppm or less based on a signal from the photodetector.

[0086] Appendix 9 The fire extinguishing agent remote measurement device according to any one of claims 1 to 7 and the fire extinguishing agent remote measurement method according to claim 8, wherein the fire extinguishing agent comprises CF3CF2C(O)CF(CF3)2.

[0087] Appendix 10 The remote measurement device and remote measurement method for a fire extinguishing agent according to Appendix 9, wherein the wavelength of the laser light is 210 nm or more and 278 nm or less.

[0088] The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is defined by the claims rather than the above-described embodiments, and it is intended to include any modifications within the scope of the claims and meanings equivalent to the claims. [Explanation of symbols]

[0089] 1 Fire extinguishing agent storage container, 2 Flexible tube, 3 Pressure switch for storage container, 4 Pressure switch for sensing tube, 5. Container fixing bracket, 6. Copper pipe connection joint, 11. Sensing tube filling joint, 15. Container support body, 19. Container valve, 20. Container support, 24. Sensing tube, 25. Copper pipe for discharging fire extinguishing agent, 31. Cable tray, 32. Flame retardant sheet, 33. Fixing band, 34. Spray nozzle for discharging fire extinguishing agent, 60. Cable tray fire extinguishing equipment, 101 Optical gas sensor, 102, suction pump, 103, flexible piping, 110, gas detection unit, 111, small optical bench, 112, incident microlens, 113, receiving microlens, 118, micromirror, 120, incident optical fiber, 121, 131, ferrule, 130, receiving optical fiber, 151, metal duct, 152, worker, 155, extension device, 201, remote measurement device, 210, laser device, 211, oscillator, 212, harmonic generator, 220, telescope, 230, spectroscopic optical system, 240, photodetector, 251, 252 Total reflection mirror, 260 processing device, 270 irradiated space, 300 measuring device, 301 tunable laser light source, 302 mirror, 303 high-sensitivity spectrometer, 304 convex lens, 305 long-pass filter, 306 gas cell, 311 laser light, 312 resonant Raman scattered light, 400 measuring device, 401 photodetector, 402 filter, 403 telescope, 404 laser device, 405 total reflection mirror, 406 emission system, 407 bottle, 411 laser light, 412 resonant Raman scattered light.

Claims

1. a cable tray for holding cables; a sensing tube provided in the cable tray and melting due to the heat of a fire, the sensing tube having a fire extinguishing agent therein; an open-type injection nozzle provided in the cable tray for discharging a fire extinguishing agent; a covering member that covers the cable tray; and a piping capable of supplying a fire extinguishing agent to the injection nozzle, sucking gas from within the cable tray through the piping and the injection nozzle; and analyzing the aspirated gas to detect leaks of fire extinguishing agent.

2. 2. The cable tray inspection method according to claim 1, wherein the step of detecting a leak of the fire extinguishing agent includes irradiating the aspirated gas with laser light to detect a leak of the fire extinguishing agent based on a Raman scattering wavelength having a peak characteristic specific to the fire extinguishing agent.

3. The extinguishing agent is CF ３ CF ２ C(O)CF(CF ３ ) ２ 3. The cable tray inspection method according to claim 1, further comprising:

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