JP7720577B2 - Cable Tray Inspection Method - Google Patents

Description

This invention relates to a cable tray inspection method.

A conventional cable tray is disclosed, for example, in Japanese Patent Application Laid-Open No. 2022-48318 (Patent Document 1).

Japanese Patent Application Laid-Open No. 2022-48318

With conventional cable trays, it was difficult to detect fire extinguishing agent leaks.

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.

In a cable tray inspection method that includes these steps, the fire extinguishing agent inside the cable tray can be sucked out using conventional open-type spray nozzles and piping. As a result, the fire extinguishing agent inside the cable tray can be analyzed and tested for leaks without disassembling the cable tray.

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

In this case, the peak of the Raman scattering wavelength is sufficiently large that it is possible to reliably detect fire extinguishing agent leaks. Furthermore, fire extinguishing agents can be detected not only by resonant Raman scattering but also by simple Raman scattering, depending on the concentration.

Preferably, the extinguishing agent comprises _CF3CF2C (O)CF( _CF3 ) _{2 .}

1 is a schematic diagram of a cable tray fire extinguishing system 60 according to a first embodiment. FIG. FIG. 2 is a front view of the container support 20 according to the first embodiment. 1A to 1C are diagrams illustrating an inspection method for a cable tray fire extinguishing system 60 according to a first embodiment. 1A to 1C are schematic diagrams illustrating a process of gas analysis using the optical gas sensor 101. 1 is a graph showing the characteristics of a fire extinguishing agent (FK-5-1-12), and a graph showing a resonance Raman spectrum. FIG. 10 illustrates a method and apparatus for measuring extinguishing agent leakage using a remote sensing device 201 according to a second embodiment. 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. FIG. 10 is a block diagram showing a configuration of a remote measurement device 201 according to a second embodiment. FIG. 3 is a diagram of a measurement apparatus 300 for a resonance Raman spectrum using a wavelength-tunable laser beam. 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. 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. 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. 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. FIG. 4 is a diagram of an apparatus 400 for measuring a resonance Raman spectrum using laser light in an open system. 10 is a graph showing the relationship between the distance from the measurement device 400 and the signal strength in an open system. This is resonance Raman spectrum data obtained when a gas of a fire extinguishing agent (FK-5-1-12) is irradiated with laser light having a wavelength of 210 nm. This is resonance Raman spectrum data obtained when a gas of a fire extinguishing agent (FK-5-1-12) is irradiated with laser light having a wavelength of 225 nm. This is resonance Raman spectrum data obtained when a gas of a fire extinguishing agent (FK-5-1-12) is irradiated with laser light having a wavelength of 250 nm. This is resonance Raman spectrum data obtained when a gas of a fire extinguishing agent (FK-5-1-12) is irradiated with laser light having a wavelength of 266 nm. This is resonance Raman spectrum data obtained when a gas of a fire extinguishing agent (FK-5-1-12) is irradiated with laser light having a wavelength of 278 nm.

Embodiments will be described below with reference to the drawings. Identical or corresponding parts will be designated by the same reference symbols, and their descriptions will not be repeated.

(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.

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

The sensing tube 24 is constantly pressurized. The sensing tube 24 extends into the cable tray 31. The cable tray 31 is installed in factories, buildings, power plants, etc. The cable tray 31 is cylindrical and has a cable 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 with a fixing band 33. A stainless steel band is wrapped around the cable tray 31 in the same position as the fixing band 33 to prevent the flame-retardant sheet 32 from sagging into the cable tray 31.

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.

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

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

When the pressure inside the sensing tube 24 drops, the container valve 19 activates, and the extinguishing agent (FK-5-1-12) is released from the extinguishing agent discharge nozzle 34 inside the cable tray 31 through the extinguishing agent discharge copper pipe 25.

When the pressure inside the sensing tube 24 drops, the sensing tube pressure switch 4 activates and issues a signal.

When the pressure inside the fire extinguishing agent storage container 1 drops, the storage container pressure switch 3 activates and an alarm signal is sent.

Cable trays 31 are often installed near the ceiling of a building, and because they are located at such a high altitude, they cannot be inspected without scaffolding, making inspection work extremely labor-intensive.

The cable tray 31 is an enclosed space, and a fire-retardant sheet 32 is wrapped around it to prevent the spread of fire and keep the fire extinguishing agent (FK-5-1-12) contained within the cable tray 31. This means that the inside of the cable tray 31 cannot be visually inspected.

Figure 2 is a front view of the container support device 20 according to embodiment 1.

The container support body 15 is primarily made of steel square pipes and angle bars. The container support body 15 is constructed by welding steel materials. It has sufficient strength to hold multiple fire extinguishing agent storage containers 1.

The fire extinguishing agent storage container 1, which is composed of a cylinder, stores a liquid fire extinguishing agent such as FK-5-1-12. In this embodiment, three fire extinguishing agent storage containers 1 are provided in parallel, but more or fewer fire extinguishing agent storage containers 1 may also be provided.

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

The pressure inside the fire extinguishing agent storage container 1 is constantly monitored, and if this pressure drops, the storage container pressure switch 3 is activated and a signal is sent. This signal is then transmitted to a monitoring room, etc.

The pressure inside the sensing tube 24 is constantly monitored, and a drop in this pressure activates the sensing tube pressure switch 4, which issues a signal. The signal is then transmitted to a monitoring room, etc.

Based on these communication signals, monitoring rooms and other locations can recognize that a fire has occurred.

The container fixing bracket 5 engages with the container support body 15 to hold the fire extinguishant storage container 1. Threads are provided on the outer 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 these threads.

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.

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.

Figure 3 is a diagram showing an inspection method for the cable tray fire extinguishing system 60 according to embodiment 1. As shown in Figure 3, during inspection, a flexible pipe 103 is connected to the extinguishing agent 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 within the cable tray 31 is sucked in via the extinguishing agent discharge copper pipe 25 and the open-type extinguishing agent discharge jet nozzle 34.

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, which serves as an analyzer.

4 is a schematic diagram showing the process of gas analysis using the optical gas sensor 101. For example, the measurement visualization device described in Japanese Patent Application Laid-Open No. 2013-167497 can be used as the optical gas sensor 101. The optical gas sensor 101 measures whether or not CF ₃ CF ₂ C(O)CF(CF ₃ ) ₂ (FK-5-1-12: NOVEC (registered trademark) 1230) contained in the fire extinguishing agent is contained in the drawn-in gas.

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

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, avalanche photodiode, phototransistor, or CCD, and guides Raman scattered light generated in the gas detection unit 110 to the photodetector as indicated by arrow 183. The photodetector is also connected to an analog-to-digital converter (ADC) and a computer. The type and concentration of gas present in the gas detection unit 110 can be calculated from the detection signal of the photodetector using known methods. For example, by inserting an interference filter between the receiving optical fiber 130 and the photodetector and using the interference filter to select Raman scattered light corresponding to the target gas, the concentration of the target gas can be measured. Furthermore, the type of gas present in the gas detection unit 110 can be identified by replacing the interference filter.

The gas detection unit 110 is the part that is directly exposed to the gas to be measured, and corresponds to a probe that is fixed to the location where the gas is to be measured (measurement position), such as inside a pipe. The gas detection unit 110, light source, and 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 can be fixed to the measurement position, and other devices such as the light source and photodetector can be installed away from the measurement position.

The gas detection unit 110 consists of a compact optical bench 111, an incident-side microlens 112, and a receiving-side microlens 113. The compact optical bench 111 is a flat plate member measuring several millimeters to several tens of millimeters square.

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. A micromirror 118 is integrally formed on the compact optical bench 111.

Raman scattering 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 determined from the Raman scattered light intensity. Furthermore, when the laser wavelength matches the substance's specific resonant excitation wavelength, 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.

In this embodiment, the gas detection unit 110 is configured with a Raman scattering optical system that directs laser light emitted from the tip of the incident-side optical fiber 120 into the gas to be measured, and then directs Raman scattered light emitted by the interaction between the laser light and the gas to be measured into the tip of the receiving-side optical fiber 130.

Examples of parameters for measuring extinguishing agent gas are shown below. The Raman scattering optical system configured in the gas detection unit 110 of the optical gas sensor 101 used in the test had an angle α between the optical axis of the incident-side optical fiber 120 and the normal to the reflective surface of the micromirror 118 of 8.6°, an angle β between the optical axis of the incident-side optical fiber 120 and the optical axis of the receiving-side optical fiber 130 of 151.9°, a distance between the incident-side microlens 112 and the micromirror 118 on the optical axis of the incident-side optical fiber 120 of 20.0 mm, and a distance between the receiving-side microlens 113 and the optical axis of the incident-side optical fiber 120 on the optical axis of the receiving-side optical fiber 130 of 9.55 mm. The light source connected to the incident optical fiber 120 was a second-harmonic laser beam from an Nd:YAG laser (Explorer, manufactured by Spectra-Physics) with an oscillation wavelength of 532 nm, and the photodetector connected to the receiving optical fiber 130 was a photomultiplier tube (R3896, manufactured by Hamamatsu Photonics). Gas was introduced into the gas detection unit 110 from the flexible piping 103, and the signal intensity obtained by the photodetector was measured.

In this embodiment, the extinguishing agent gas is analyzed using Raman scattered light from the irradiated extinguishing agent gas, but the extinguishing agent gas may also be analyzed using other methods, such as ultraviolet absorption spectroscopy.

Furthermore, although an example has been shown in which CF ₃ CF ₂ C(O)CF(CF ₃ ) 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.

In the analysis method configured as described above, extinguishing agent leaks are detected by sucking in gas from within the cable tray 31 via the open-type extinguishing agent discharge jet nozzle 34 and the extinguishing agent discharge copper pipe 25 and analyzing that gas, making it possible to make maximum use of existing equipment and detect extinguishing agent leaks within the cable tray 31 with high accuracy. This makes it possible to test for extinguishing agent leaks within the cable tray 31 with minimal addition of new equipment.

(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 fire extinguishing agent leak using a remote measurement device 201 according to a second embodiment.

In embodiment 2, the resonance Raman spectrum of the extinguishing agent is used to measure the concentration of the extinguishing agent present at a distance and detect extinguishing agent leaks from pipes, tubes, etc.

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

As shown in Figure 5, the peaks A1 to A3 represent the resonance Raman spectrum peaks of the fire extinguishing agent gas. Of these, the peak A1 with the highest light intensity, 754.6 cm ^-1 , which corresponds to a wavelength of 271.4 nm, was adopted as the observation wavelength.

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 fire extinguishing agent (FK-5-1-12). Specifically, it identifies the type of substance and locates its location by capturing Raman scattered light (Figure 5) emitted from the fire extinguishing agent. By scanning with laser light, 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 identify the location of the leak.

The worker 152 holds a handheld remote measurement device 201. The remote measurement device 201 emits laser light in the direction indicated by arrow 202. The laser light emitted by the remote measurement device 201 is irradiated onto the metal duct 151 used to secure the sensing tube 24, the portion of the sensing tube 24 where the metal duct 151 is not present, and the cable tray 31. The remote measurement device 201 receives the resulting Raman scattered light (resonance Raman spectrum: Figure 5), and from the information on the received light, it is possible to determine whether extinguishing agent is leaking in the irradiated area.

Unlike embodiment 1, the remote measurement device 201 according to embodiment 2 does not require the extinguishing agent in the cable tray 31 to be moved near the remote measurement device 201. This makes it possible to detect extinguishing agent leaks in difficult-to-reach locations.

Figure 7 is a diagram showing a method and apparatus for measuring extinguishing agent leakage from multiple tiers of cable trays 31 using a remote measurement device 201 according to embodiment 2. As shown in Figure 7, when multiple tiers of cable trays 31 are stacked, the remote measurement device 201 is attached to an extension device 155 that extends upward from the ground. This allows the remote measurement device 201 to be brought close to the cable tray 31 of the tier to be measured. As a result, the remote measurement device 201 can be brought close to the gaps between each cable tray 31, making it possible to measure extinguishing agent leakage from each tier of cable trays 31.

Figure 8 is a block diagram showing the configuration of a remote measurement device 201 according to embodiment 2. As shown in Figure 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.

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, converting the laser light oscillated by the oscillator 211 into a harmonic (e.g., the fifth harmonic) and emitting it to the outside. The emitted laser light is emitted into the irradiated space 270 via total reflection mirrors 251 and 252.

The type of laser device 210 is not particularly limited, but a solid-state laser is preferable. A typical solid-state laser is configured to excite a laser medium placed in 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 called a laser crystal 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 the pulse width of a solid-state laser is approximately 5 to 10 ns. For example, the microchip type DPSS-L of this embodiment is a device that includes a semiconductor laser, a collimating lens, a laser crystal with an HR coating, a saturable absorber, an output mirror, and an SHG crystal, and significantly miniaturizes the solid-state laser while ensuring a constant output from the solid-state laser. Examples of laser crystals for the microchip type DPSS-L include Nd:YAG, Nd:YLF, Nd:glass, Nd:YVO ₄ , Yb:YAG, and Nd:GVO.

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 by applying a reflective coating (HR coat) to one end of the laser crystal, the laser crystal itself functions as a resonator mirror. Furthermore, a crystal known as a saturable absorber, which becomes transparent when a certain amount of energy is accumulated, is used to function as a Q-switch. The microchip type DPSS-L achieves compactness and robustness by monolithically integrating these crystals and optical elements.

In this way, by using a microchip laser, which is an ultra-compact pulse laser, as the oscillator 211 of the laser device 210, the laser device 210 or the entire remote measurement device 201 can be made smaller and its robustness increased. Microchip lasers can also be integrated with the harmonic generator 212, such as a microchip laser that emits the fifth harmonic of Nd:YAG.

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

When a laser device is designed to identify multiple substances, it needs to be equipped with a mechanism that can switch between 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 emit only laser light with a single excitation wavelength of 266 nm.

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.

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 fire extinguishing agents and 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. It is preferable that the telescope 220 be a deep-ultraviolet telescope that focuses light in the ultraviolet range around a wavelength of 271.4 nm, in order to receive resonance Raman scattered light caused by the fire extinguishing agent and eliminate other light components as much as possible. In addition, in such a deep-ultraviolet telescope, it is preferable that all optical systems collect light in the deep-ultraviolet range with high efficiency, and that they be reflective in terms of efficiency and aberration.

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 effects of background light can be reduced.

The photodetector 240 is an ICCD detector, photomultiplier tube, 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 laser light irradiation pulse, and is configured to receive only light during the period when resonant Raman scattered light is emitted (the period when the laser light is applied) by opening and closing the gate.

The processing device 260 calculates the distance from the remote measurement device 201 to the extinguishing agent from the return time of the Raman scattered light or resonance Raman scattered light. The remote measurement device 201 also has a scanning device that can change the direction of laser light emission (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). Based on control commands from the processing device 260, the light emitted from the laser device 210 can be scanned vertically and horizontally, or horizontally and tiltingly, within the irradiated space 270, thereby measuring the spatial distribution of the extinguishing agent. The remote measurement device 201 can detect the resonance Raman scattered light caused by the extinguishing agent while gradually changing the angle of the laser light emission direction and the direction of light reception of the resonance Raman scattered light, thereby measuring the three-dimensional distribution of the extinguishing agent within a range with a radius of 15 meters, for example, centered on the remote measurement device 201.

Because 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 having 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, because the Raman shift of the Raman scattered light caused by the atmospheric components and the Raman shift of the resonant Raman scattered light caused by the fire extinguishing agent do not overlap, the photodetector 240 can detect the received signal of the resonant Raman scattered light caused by the fire extinguishing agent even in the atmosphere without interference from the Raman scattered light caused by the atmospheric components. For example, when irradiated with a 266 nm laser light, the Raman shift of the Raman scattered light caused by oxygen is 1556 cm ⁻¹ , the Raman shift of the Raman scattered light caused by nitrogen is 2331 cm ⁻¹ , and the Raman shift of the Raman scattered light caused by water vapor is 3652 cm ⁻¹ . By detecting the received light signal at 754.6 cm ⁻¹ (271.4 nm, A1 in FIG. 5 ), which has the highest light intensity among the Raman shifts of the resonant Raman scattering light caused by the fire extinguishing agent, it is possible to separate the fire extinguishing agent from atmospheric components and detect it even in the atmosphere.

In particular, the photodetector 240 detects the signal intensity at a Raman shift of 2000 cm ⁻¹ or less, where the signal intensity of the received light signal is particularly large, and in this embodiment, the received light signal at a Raman shift of 754.6 cm ⁻¹ was detected.

(Resonance Raman spectra at wavelengths of 210 nm and 266 nm in a closed system)
9 is a diagram of a resonance Raman spectrum measurement apparatus 300 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.

Samples 1 and 2 using FK-5-1-12 gas were sealed in gas cells, and the resonant Raman spectrum data obtained when the wavelength of laser light 311 was 210 nm with 1 mJ of energy and the wavelength was 266 nm with 3 mJ of energy are shown in FIGS. 10 to 13.
10 to 13, the peaks indicated by A11 to A15 and A21 to A23 are derived from FK-5-1-12 (note that the number of detectable peaks varies depending on the influence of 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 of the fire extinguishing agent by irradiating the sample with laser light and receiving the resonant Raman scattering wavelength with peak characteristics specific to the fire extinguishing agent.

(Resonance Raman spectrum in an open system)
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 release system 406 was installed 7 meters away from measurement device 400, which is a remote measurement device for fire extinguishing agent (FK-5-1-12). FK-5-1-12 was released into the atmosphere from release 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.

Laser light 411 with a wavelength of 266 nm and a pulse energy of 1 mJ was emitted from the laser device 404 of the remote measurement device in the direction indicated by the arrow, reflected by a total reflection mirror 405, and irradiated onto the measurement point (irradiated space) of the emission system 406. In addition to irradiating the laser light, resonant Raman scattered light 412 incident from the irradiated space was collected by the 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 the 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.

In order to detect the resonant Raman scattered light caused by FK-5-1-12, the measuring device 400 is equipped with a filter 402 that has an edge filter that passes light with wavelengths of 266 nm or longer, and a bandpass filter that extracts the resonant Raman scattered 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 one second.

Measurement conditions) Distance: 7 m, liquid FK-5-1-12 vaporized at room temperature, number of averaging: 750, observed wavelength: 271.4 nm (Raman shift = 754.6 cm ^-1 )
From FIG. 15, the presence of gas FK-5-1-12 was detected at a distance of 7 m.

(Raman shifts for various excitation wavelengths in a closed system)
Using the apparatus shown in Figure 9, the Raman shift of FK-5-1-12 as a fire extinguishing gas was investigated at excitation wavelengths of 210 nm, 225 nm, 250 nm, 266 nm, and 278 nm. As a result, Raman shifts of 760.4 cm ^-1 , 1250.6 cm ^-1 , and 1780.7 cm ^-1 were confirmed at each wavelength. Detailed resonance Raman spectrum data are 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 and displayed.

This enabled us to detect the fire extinguishing agent gas FK-5-1-12 at various excitation wavelengths.

According to the present disclosure, a received light signal can be detected at a Raman shift of 2000 cm ⁻¹ or less, more preferably 1800 cm ⁻¹ , and more specifically at a Raman shift (resonance Raman scattering wavelength) of 1780.7 cm ⁻¹ or less.

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 optical detection device detects a received light signal at a Raman shift of 2000 cm ⁻¹ or less.

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 incident from the irradiated space in an open space.

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.

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.

Appendix 5
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.

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.

Appendix 7
7. The remote measurement device for a fire extinguishing agent according to any one of claims 1 to 6, wherein the light detection device detects a received light signal at a Raman shift of 760.4 cm ⁻¹ .

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;
detecting the fire extinguishing agent by receiving resonance Raman scattered light at a Raman shift of 2000 ^{cm or} less from the irradiated space using a light detection device;
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 light detection device.

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 .}

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

The embodiments disclosed herein are illustrative in all respects and should not be considered limiting. The scope of the present invention is indicated by the claims, not by the above-described embodiments, and is intended to include all modifications equivalent to and within the scope of the claims.

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 side microlens, 113 light receiving side microlens, 118 micromirror, 120 incident side optical fiber, 121, 131 ferrule, 130 light receiving side optical fiber, 151 metal duct, 152 operator, 155 extension device, 201 remote measurement device, 210 laser device, 211 oscillator, 212 harmonic generator, 220 telescope, 230 spectroscopic optical system, 240 light detection device, 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 (3)

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. The cable tray inspection method of claim 1, wherein the step of detecting the extinguishing agent leak includes irradiating the aspirated gas with laser light and detecting the extinguishing agent leak based on the Raman scattering wavelength of the peak characteristic specific to the extinguishing agent. The cable tray inspection method according to claim 1 or 2, wherein the extinguishing agent comprises _CF3CF2C (O)CF( _CF3 ) _{2 .}