Method for monitoring gas leaks and confirming gas emissions inside cable trays

Abstract

To provide a method for monitoring a gas leak inside a cable tray that enables easier equipment maintenance, and a method for confirming gas release.SOLUTION: A cable tray fire extinguishing system includes: a cable tray that holds a cable; a detection tube that is disposed inside the cable tray and melts due to fire heat; a spray nozzle that is disposed inside the cable tray to eject fire extinguishing agents; and a covering member that covers the cable tray. Without removing the covering member, the inside of the cable tray is monitored by a monitoring member.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for monitoring gas leakage and a method for confirming gas release inside a cable tray. [Background technology]

[0002] Utility Model Registration No. 3160699 (Patent Document 1) and Utility Model Registration No. 3179000 (Patent Document 2) disclose an automatic fire extinguishing device using a fire detection tube. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Utility model registration No. 3160699 [Patent Document 2] Utility model registration No. 3179000 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional devices have the problem of being difficult to maintain. [Means for solving the problem]

[0005] A method for monitoring gas leakage inside a cable tray and a method for confirming gas release according to the present invention are provided in a cable tray fire extinguishing system which includes a cable tray for holding a cable, a sensing tube provided inside the cable tray which melts due to the heat of a fire, an injection nozzle for releasing a fire extinguishing agent into the cable tray, and a covering member which covers the cable tray, in which a monitoring member monitors the condition inside the covering member.

[0006] The gas emission confirmation method (confirmation of gas emission from the injection nozzle) is to confirm that there are no foreign objects in the extinguishing copper pipe and that the injection head is not clogged by checking whether or not air is ventilating from the injection nozzle during inspection, etc.

[0007] In addition, in order to identify the location where gas is being emitted from the injection nozzles, it is necessary to confirm that gas is being emitted from all of the installed injection nozzles.

[0008] The method for monitoring gas leakage from a cable tray and the method for confirming gas emission configured in this manner include a monitoring member for monitoring the condition inside the covering member. Monitoring the condition inside the cable tray with the monitoring unit facilitates maintenance and inspection of the device. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a cable tray fire extinguishing system 60 according to a first embodiment. [Diagram 2] 1 is a front view of a container support 20 according to a first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment will be described with reference to the drawings. The same or corresponding parts are designated by the same reference characters and description thereof will not be repeated.

[0011] 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 is attached to the upper part of a fire extinguishing agent storage container 1. The fire extinguishing agent storage container 1 is supported by a container support body 15.

[0012] Connected to the container valve 19 are a copper pipe 25 for discharging the 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 is not limited to being directly connected to the container valve 19, but may be connected somewhere along the path of 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 necessarily have to be connected.

[0013] The inside of the sensing tube 24 is constantly pressurized. A cable tray 31 is installed in a factory, a building, a power plant, etc. The cable tray 31 is cylindrical and has a cable installed therein. The cable tray 31 is covered with a flame-retardant sheet 32. 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 to prevent the flame-retardant sheet 32 ​​from sagging into the cable tray.

[0014] A sensing tube 24 is provided in 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 in the cable tray 31. A jet nozzle 34 for discharging a fire extinguishing agent is attached to the copper pipe 25 for discharging a fire extinguishing agent.

[0015] For example, a halogenated extinguishing agent, FK-5-1-12, is enclosed in the extinguishing agent storage container 1. This agent is pressurized by nitrogen inside the extinguishing agent storage container 1. This nitrogen is supplied to the sensing tube 24 via the sensing tube pressure switch 4. When supplying nitrogen into the sensing tube 24 during installation, if nitrogen is introduced from the extinguishing agent storage container 1, the amount of nitrogen inside the extinguishing agent storage container 1 will decrease. Therefore, nitrogen may be filled into the sensing tube 24 from outside the extinguishing agent storage container 1.

[0016] When the heat of the fire causes the sensing tube 24 to melt, the pressure within the sensing tube 24 drops.

[0017] 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.

[0018] When the pressure inside the sensing tube 24 drops, the sensing tube pressure switch 4 is activated and a signal is sent out.

[0019] When the pressure inside the extinguishant storage container 1 drops, the storage container pressure switch 3 is activated and a notification signal is sent.

[0020] FIG. 2 is a front view of container support 20 according to the first embodiment.

[0021] 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.

[0022] The extinguishant storage container 1, which is constituted by a cylinder, stores a liquid extinguishant such as FK-5-1-12. In this embodiment, three extinguishant storage containers 1 are provided in parallel, but more or less extinguishant storage containers 1 may be provided.

[0023] The container valve of the extinguishant storage container 1 is connected to a copper pipe connection joint 6 by a flexible tube 2. As a result, the extinguishant in the extinguishant storage container 1 is supplied to the copper pipe connection joint 6 via the flexible tube 2.

[0024] The pressure inside the fire extinguishing agent storage container 1 is constantly monitored, and if the pressure drops, the storage container pressure switch 3 is activated and a signal is sent to a monitoring room or the like.

[0025] 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 notification signal. The notification signal is then transmitted to a monitoring room or the like.

[0026] Based on these communication signals, a monitoring room or the like can recognize that a fire has occurred.

[0027] The container fixing metal fitting 5 engages with the container support body 15 to hold the fire extinguishant storage container 1. A screw thread is provided on the outer peripheral surface of the end of the container fixing metal fitting 5, and the container fixing metal fitting 5 can be fixed to the container support body 15 by screwing a nut onto the screw thread.

[0028] 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 inside the copper pipe connection joint 6.

[0029] 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.

[0030] 1 again, the cable tray fire extinguishing system 60 has an ultrasonic camera 71 as a monitoring member. A maintenance method and a maintenance management method using the ultrasonic camera 71 will be described.

[0031] The ultrasonic camera 71 is used to improve the efficiency of maintenance, management, and diagnosis of cable tray fire extinguishing equipment.

[0032] A fire extinguishing agent ejection nozzle 34 and a sensing tube 24 are installed inside the cable tray 31. To make the inside of the cable tray 31 an enclosed space, a flame retardant sheet 32 ​​or the like is wrapped around the outer periphery of the cable tray 31. The flame retardant sheet 32 ​​is wound continuously with a portion overlapping. Instead of the flame retardant sheet 32, a steel plate cover may be used.

[0033] The following must be checked as part of the maintenance and management diagnosis of the cable tray fire extinguishing system 60 upon completion of installation work, during regular maintenance, etc.

[0034] (1) Leak diagnosis of sensing tube 24 (2) Check the ventilation status of the copper pipe 25 for discharging the fire extinguishing agent Since a flame-retardant sheet 32 ​​or the like is wrapped around the outer periphery of the cable tray 31, leakage from the sensing tube 24 and ventilation from the extinguishing agent discharge nozzle 34 cannot be directly (visually) confirmed.

[0035] In addition, the cable tray 31 is located at a high place, such as near the ceiling, making it difficult to check. In order to check, it is necessary to set up scaffolding and peel off the flame-retardant sheet 32, which is not an easy task.

[0036] The cable tray fire extinguishing system 60 has one extinguishing agent storage container 1, and is intended to extinguish a cable tray 31 approximately 50 m long. The sensing tubes 24 are installed over the entire surface of the cable tray 31. Up to eight extinguishing agent discharge nozzles 34 are installed at intervals of approximately 6 m. This makes it necessary to check a wide area at the same time.

[0037] It is relatively easy to check for leaks from the visually visible detection tube 24 / fire extinguishing piping installed outside the cable tray 31 unless the leaks are at a high altitude, but the problem is how to check inside the cable tray 31 (hidden area) that is covered with a flame-retardant sheet 32 ​​or the like.

[0038] Until now, it has been necessary to set up scaffolding, remove the flame-retardant sheet 32, and check the structure, which requires extensive work.

[0039] The inventors have found that by using an ultrasonic camera 71, it is possible to visualise gas leaks or ventilation from a spray nozzle during inspection without contacting the nozzle. The ultrasonic camera 71 detects ultrasonic waves emitted from the leak point or gas release point and makes them visible.

[0040] It was found that by using an ultrasonic camera 71, emitted sounds and leaking sounds generated within a cable tray covered with a flame-retardant sheet 32 ​​leak from gaps in the flame-retardant sheet 32, and by picking up the sounds, it is possible to easily confirm them from a distance without contact.

[0041] This makes it possible to check a wide area of ​​several to tens of meters from outside the tray at once without setting up scaffolding or removing the flame-retardant sheet 32, thereby reducing the manpower required and making equipment maintenance and diagnosis significantly more efficient.

[0042] For example, the ultrasonic camera 71 detects a gas leak, and the information is sent to the control unit 72. The control unit 72 judges from which part the gas is leaking based on the frequency, volume (amplitude) of the sound, the distance to the sound source, and the like. Then, the control unit 72 can transmit the information of the gas leak to the display unit 14. The display unit 14 can also display, for example, which of the sensing tubes 24 connected to the extinguishant storage container 1 the gas has leaked from. If a plurality of ultrasonic cameras 71 are installed, it is also possible to easily determine from which part of the cable tray 31 extending in the longitudinal direction the gas has leaked. It is not necessary to transfer the information from the control unit 72 to the display unit 14. In that case, the information is visually confirmed by images or videos on the display unit of the ultrasonic camera 71 itself or on a separately installed output screen (not shown), etc.

[0043] For example, the multiple ultrasonic cameras 71 are arranged along the longitudinal direction of the cable tray 31. When multiple ultrasonic cameras 71 detect a leak, the control unit 72 determines that the leak has occurred at the location of the ultrasonic camera 71 that detected the loudest sound. Then, it is also possible to blink or light up the lamp on the display unit 14 corresponding to that sensing tube 24.

[0044] The ultrasonic camera 71 is used as a maintenance and management diagnostic system for equipment that requires inspection of concealed parts. This system may be used not only for the cable tray 31, but also for detecting leaks such as leakage from pipes at high places, leakage detection in an environment where the noise of other equipment is so loud that the human hearing cannot hear the leakage sound from the detection part, leakage detection in a location where there are multiple leakage confirmation locations and it takes time to confirm, leakage detection of a test object where it is difficult to apply leakage detection liquid, leakage detection in a location where there is an obstacle and direct access is not possible, leakage detection in a location where humans cannot easily approach due to high temperature / low temperature / bad environment, leakage detection from a pipe in the ceiling attic after the ceiling board is installed, etc. The monitoring member and ultrasonic camera 71 may not only be permanently installed in the cable tray fire extinguishing equipment 60, but may not be permanently installed. If they are not permanently installed, the monitoring member and ultrasonic camera 71 are not present during normal operation of the cable tray fire extinguishing equipment 60. The monitoring member and ultrasonic camera 71 are used to detect gas leakage inside the cable tray 31 and gas emission from the injection nozzle during inspection.

[0045] In addition, it can be used as a maintenance and diagnostic system for piping in nuclear power plants, where it is difficult for people to enter. In nuclear power plants, there are areas of high radioactivity, and it is difficult to enter such areas for inspection. Even if the reactor is shut down, the radioactive materials do not disappear, so it is always difficult to enter.

[0046] Dry sprinklers are sometimes used in nuclear power plants. In dry sprinklers, the secondary pipe where the spray head is installed does not normally contain water. The secondary pipe can be at normal pressure, positive pressure (pressurized), or negative pressure. When a crack, fissure, or pinhole occurs in the secondary pipe under these normal conditions, and gas flows between the inside and outside of the secondary pipe, ultrasonic waves are generated. By detecting this ultrasonic wave with an ultrasonic camera, it is possible to detect leaks in the secondary pipe.

[0047] Furthermore, instead of using only the ultrasonic camera 71, the gas inside the sensing tube 24 may contain visible components (for example, smoke components), and the camera may detect any smoke leaking from the sensing tube 24. In this case, a visible light, infrared, or ultraviolet camera may be used as the camera member (monitoring member).

[0048] A monitoring member other than the ultrasonic camera 71 may be used that detects audible or ultrasonic vibrations generated in the cable tray 31 and applies them to the extinguishing agent discharge copper pipe 25 and / or the sensing tube 24 within reach to check for leaks. Furthermore, the monitoring member may include the ultrasonic camera 71 and a vibration detector, and the accuracy may be improved by using them in combination.

[0049] (Appendix 1) a cable tray for holding the cables; A sensing tube provided in the cable tray and melted by heat of a fire; an injection nozzle disposed within the cable tray for discharging a fire extinguishing agent; A cable tray fire extinguishing system comprising: A method for monitoring gas leakage and a method for confirming gas emission inside a cable tray, in which a monitoring member monitors the condition inside the covering member.

[0050] (Appendix 2) A method for monitoring gas leakage and a method for confirming gas release inside a cable tray as described in Appendix 1, further comprising a control unit for controlling the monitoring member.

[0051] (Appendix 3) The method for monitoring gas leakage and the method for confirming gas release inside a cable tray according to appendix 1 or 2, wherein the monitoring member is an ultrasonic camera.The method for monitoring gas leakage and the method for confirming gas release inside a cable tray according to appendix 1 or 2, wherein the monitoring member is a detector that detects audible or ultrasonic vibrations generated inside the cable tray 31 against a copper tube for discharging a fire extinguishing agent and / or a detection tube to confirm leakage.The method for monitoring gas leakage and the method for confirming gas release inside a cable tray according to appendix 1 or 2, wherein the monitoring member includes an ultrasonic camera and a vibration detector.

[0052] (Appendix 4) A method for monitoring gas leakage and confirming gas release inside a cable tray as described in Appendix 1 or 2, in which a visible fluid flows through the sensing tube and leakage of the fluid is detected by the monitoring member.

[0053] (Appendix 5) 1. A nuclear power plant having a dry sprinkler system, the nuclear power plant comprising an ultrasonic monitoring member for monitoring a secondary piping of the dry sprinkler system.

[0054] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0055] 1 Extinguishing agent storage container, points 1a, 1b, 1c, 1d, 2 Flexible tube, 3 Pressure switch for storage container, 4 Pressure switch for detection tube, 5 Container fixing bracket, 6 Copper pipe connection joint, 11 Detection tube filling joint, 12 Solenoid valve for detection tube, 13 Pressure switch for reducing detection tube pressure, 15 Container support body, 19 Container valve, 20 Container support, 24 Detection tube, 25 Copper pipe for discharging extinguishing agent, 31 Cable tray, 32 Flame retardant sheet, 33 Fixing band, 34 Spray nozzle for discharging extinguishing agent, 60 Cable tray fire extinguishing equipment, 71 Ultrasonic camera, 72 Control unit.

Claims

1. an elevated cable tray for holding the cables; A sensing tube provided in the cable tray and melted by heat of a fire; A spray nozzle provided in the cable tray for discharging a fire extinguishing agent; A cable tray fire extinguishing system comprising: A monitoring member monitors the inside of the cable tray without removing the covering member, the monitoring member being an ultrasonic camera, and leakage sound generated inside the cable tray covered with the covering member leaks through gaps in the covering member and the sound is picked up by the ultrasonic camera.

2. A method for monitoring gas leaks inside a cable tray as described in claim 1, wherein information from the ultrasonic camera is sent to a control unit, and the control unit determines from which location gas is leaking based on the sound frequency, volume, and distance to the source of the sound.

3. A method for monitoring gas leaks inside a cable tray as described in claim 1, wherein a plurality of ultrasonic cameras are provided and information thereof is sent to a control unit, the plurality of ultrasonic cameras are arranged along the longitudinal direction of the cable tray, and when a leak is detected by the plurality of ultrasonic cameras, the control unit determines that the leak has occurred at the installation location of the ultrasonic camera that detected the loudest sound.

4. an elevated cable tray for holding the cables; A sensing tube provided in the cable tray and melted by heat of a fire; A spray nozzle provided in the cable tray for discharging a fire extinguishing agent; A cable tray fire extinguishing system comprising: A method for checking for gas emissions inside a cable tray, in which a monitoring member monitors the inside of the cable tray without removing the covering member, the monitoring member being an ultrasonic camera, and sound emitted inside the cable tray covered with the covering member leaks through gaps in the covering member and the sound is picked up by the ultrasonic camera.

Images