Detection system and detection method

Abstract

To provide a detection system and a detection method capable of improving a detection speed and a detection range of leakage gas.SOLUTION: The method includes a preliminary warning step of issuing a preliminary warning D1 when the gas detection camera 3 detects the gas leakage, a command step of transmitting a command from the command unit 8 when the concentration of the gas detected by the gas detector 2 exceeds a preset threshold value or when a signal D4 is received from the outside, an evacuation step of notifying the occurrence of the gas leakage to the inside of the ship after the preliminary warning D1 is issued and when the command is received, and a cutoff step of cutting off the supply of the liquified gas after the preliminary warning D1 is issued and when the command is received.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a detection system and a detection method for detecting gas leakage in a ship, and more particularly to a detection system and a detection method that can improve the detection speed and detection range of leaked gas. [Background technology]

[0002] Various detection systems for detecting fires on ships have been proposed (see, for example, Patent Document 1). The detection system described in Patent Document 1 detects a fire using multiple fire detectors, and extracts possible evacuation routes.

[0003] In ships fueled by liquefied gases such as liquefied natural gas, hydrogen, and ammonia, or in liquefied gas carriers, it is necessary to detect leaks of these flammable or toxic gases or liquids. A method for detecting leaked gas by installing multiple gas detectors, as in Patent Document 1, has been devised and is actually being implemented.

[0004] However, leaking gas is only detected after a liquid or gas leaks from a pipe or the like, and only when the gas reaches the gas detector after convection in the surrounding atmosphere. This creates a problem in that there is a delay between the start of the gas leak and when it is detected by the gas detector.

[0005] Furthermore, gas detectors can only detect the presence of gas at their installation location, and expanding the detection range for leaked gas would require installing a large number of gas detectors, which is not realistic. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 01-297083 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide a detection system and a detection method that can improve the detection speed and detection range of leaked gas. [Means for solving the problem]

[0008] A detection system for achieving the above-mentioned object is a detection system that is equipped with a gas detector and is installed on a ship, and is further equipped with a gas detection camera that determines the presence of gas based on images, and a control mechanism that receives signals from the gas detector and the gas detection camera, wherein the control mechanism is characterized by having an alarm unit that issues a preliminary alarm when the gas detection camera detects gas, a command unit that sends a command when the concentration of gas detected by the gas detector exceeds a predetermined threshold value or when a signal is received from outside, a notification unit that notifies the ship of the occurrence of a gas leak after the preliminary alarm has been issued and when the command has been received, and a shut-off unit that shuts off the supply of liquefied gas after the preliminary alarm has been issued and when the command has been received.

[0009] A detection method for achieving the above object is a detection method for detecting gas leaks using a gas detector that is pre-installed on a ship, and is characterized in that the ship is pre-equipped with a gas detection camera that determines the presence of gas based on an image, and a control mechanism that receives signals from the gas detector and the gas detection camera, and is equipped with the following features: a preliminary alarm step of issuing a preliminary alarm when the gas detection camera detects a gas leak; a command step of sending a command when the concentration of gas detected by the gas detector exceeds a predetermined threshold value or when a signal is received from outside; an evacuation step of notifying the ship of the occurrence of a gas leak after the preliminary alarm has been issued and when the command has been received; and a cut-off step of cutting off the supply of liquefied gas after the preliminary alarm has been issued and when the command has been received. [Effects of the Invention]

[0010] According to the present invention, leaking gas can be detected by a gas detection camera without waiting for the leaking gas to reach a gas detector. A preliminary alarm is issued at a relatively early stage after the start of gas leakage. Furthermore, the detection range of leaking gas by a gas detection camera is affected by the angle of view of the gas detection camera. A gas detection camera can detect leaking gas over a wider range than a gas detector. This is advantageous for improving the detection speed and range of leaking gas. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram illustrating a configuration of a detection system. [Figure 2] FIG. 10 is an explanatory diagram illustrating the flow of a detection method. [Figure 3] FIG. 1 is an explanatory diagram illustrating an example of an evacuation route on a ship. [Figure 4] FIG. 2 is an explanatory diagram illustrating a modified example of FIG. 1. [Figure 5] FIG. 10 is an explanatory diagram illustrating an example of a composite image. [Figure 6] FIG. 6 is an explanatory diagram illustrating a modified example of the composite image of FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0012] The detection system and the detection method will be described below based on the embodiments shown in the drawings.

[0013] As shown in FIG. 1, the detection system 1 includes a gas detector 2 installed on a ship, a gas detection camera 3, and a control mechanism 4 that receives signals from the gas detector 2 and the gas detection camera 3.

[0014] The gas detector 2 may be, for example, a semiconductor gas detector that utilizes the change in resistance that occurs when a metal oxide semiconductor comes into contact with a gas, or a controlled-potential electrolysis gas detector that detects the gas concentration by the current generated by electrolyzing a gas on an electrode maintained at a constant potential. The gas detector 2 is not limited to the above and can be configured with any known gas detector.

[0015] The gas detection camera 3 is configured to determine the presence of gas based on an image. The gas detection camera 3 is configured, for example, as an infrared camera. An infrared camera is configured to emit infrared light and capture the reflected light with a camera. If leaking gas is present, the infrared light is absorbed by the leaking gas and no reflected light is obtained. The configuration of the infrared camera is not limited to the above. The infrared camera may be configured, for example, to capture infrared light emitted from the object itself, or may have other configurations. In the area where leaking gas is present, it will be impossible to obtain images of the ship's structures, etc. The gas detection camera 3 can detect the presence or absence of leaking gas based on this image.

[0016] The control mechanism 4 has an alarm unit 5, a notification unit 6, a shutoff unit 7, and a command unit 8. The control mechanism 4 is configured, for example, by a known PC or PLC (Programmable Logic Controller). The control mechanism 4 may be incorporated into a control device of the ship.

[0017] The alarm unit 5 is configured to issue a preliminary alarm D1 when the gas detection camera 3 detects leaking gas. It can be said that the alarm unit 5 operates based on a signal from the gas detection camera 3. The preliminary alarm D1 is displayed on a specified monitor, for example. The preliminary alarm D1 may also be configured to be displayed on a predetermined mobile terminal of a crew member. The preliminary alarm D1 is notified to some of the crew members. The preliminary alarm D1 enables some of the crew members to recognize the possibility of gas leakage.

[0018] The notification unit 6 is configured to notify the ship of the occurrence of a gas leak after the preliminary alarm D1 has been issued and when a command has been received. The command is issued from the command unit 8, which will be described later. When a command has been received from the command unit 8, the notification unit 6 issues the evacuation alarm D2, for example, by sounding an alarm. If no command has been received even after the preliminary alarm D1 has been issued, the notification unit 6 does not issue the evacuation alarm D2. The notification unit 6 is not limited to being configured to sound an alarm. It may be configured to widely notify the crew of the need to evacuate, such as by turning on a warning light indicating that the evacuation alarm D2 has been issued, or by notifying the crew's mobile device of the occurrence of a gas leak.

[0019] The shutoff unit 7 is configured to perform supply cutoff D3 after a preliminary alarm D1 has been issued and upon receiving a command. The command is issued from the command unit 8. When a command is received from the command unit 8, the shutoff unit 7 performs supply cutoff D3, for example, by closing the liquefied gas supply valve. If no command has been received even after the preliminary alarm D1 has been issued, the shutoff unit 7 does not perform supply cutoff D3. The shutoff unit 7 is not limited to a configuration that shuts off the liquefied gas supply valve. The shutoff unit 7 may also have a configuration that shuts off the valve of the fuel tank, stops the liquefied gas supply pump, or stops a device for gasifying liquefied gas. It is sufficient for the shutoff unit 7 to have a configuration that prevents new gas from being supplied to the location where gas is leaking.

[0020] The command unit 8 issues a command in response to a button operation D4 by the crew. In other words, the command unit 8 is configured to issue a command when it receives an external input signal via button operation D4. The command unit 8 is also configured to issue a command when the concentration of gas detected by the gas detector 2 exceeds a preset threshold value. The command unit 8 issues a command based on button operation D4 by the crew or a signal from the gas detector 2.

[0021] A method for detecting leaked gas by the detection system 1 will be described with reference to the flow illustrated in Fig. 2. First, when a gas leak occurs, the gas is detected in a relatively short time by the gas detection camera 3. When the leaked gas is detected by the gas detection camera 3, the control mechanism 4 issues a preliminary alarm D1 (preliminary alarm step S01).

[0022] The crew member who has confirmed the preliminary alarm D1 checks the location and extent of the gas leak. If the crew member determines that evacuation is necessary, he or she operates the button D4 on the command unit 8 (determination step S02). If the preliminary alarm D1 has been issued and the button operation D4 has been performed, the command unit 8 issues a command (command step S03). The notification unit 6, having received the command from the command unit 8, issues an evacuation alarm D2 (evacuation step S04). Upon receiving the evacuation alarm D2, the crew member begins evacuation.

[0023] If the crew member who has confirmed the preliminary alarm D1 determines that it is necessary to cut off the supply of liquefied gas, they also operate the button D4 on the command unit 8 (determination step S02). When the preliminary alarm D1 has been issued and the button operation D4 has been performed, the command unit 8 issues a command (command step S03). The cutoff unit 7, having received the command from the command unit 8, executes the supply cutoff D3 (cutoff step S05).

[0024] The command unit 8 may be configured to issue a command to both the notification unit 6 and the cutoff unit 7 when the button operation D4 is performed. However, the command unit 8 may be configured to issue a command to only one of the notification unit 6 or the cutoff unit 7 depending on the content of the button operation D4. Depending on the content of the button operation D4 performed by the mariner, one or both of the evacuation step S04 and the cutoff step S05 may be configured to be executed.

[0025] If the crew member confirms the preliminary alarm D1 and determines that neither the evacuation step S04 nor the shutoff step S05 is necessary, the crew member does not operate the button D4 on the command unit 8. In this case, the evacuation alarm D2 is not issued, and the supply shutoff D3 is not executed. The crew member takes measures to deal with the gas leak (repair step S06). Specifically, the crew member takes measures such as repairing the leak by sealing the leaking area, or opening and closing valves to prevent gas from being supplied to the leaking area. During this time, no evacuation of other crew members is performed, and no liquefied gas supply valves are closed. The ship continues to navigate.

[0026] After the countermeasures such as repairs are completed, the preliminary alarm D1 is cancelled, for example, by an operation by a crew member (restoration step S07).

[0027] After the preliminary alarm D1 is issued, when the gas detector 2 detects a gas concentration exceeding the threshold, a command is issued from the command unit 8 (command step S03). When the gas detector 2 detects a leaked gas of a relatively high concentration exceeding the threshold, a command is automatically issued from the command unit 8 without waiting for a decision by the crew, etc. In other words, a command is issued from the command unit 8 without going through the decision step S02. At this time, the evacuation step S04 and the shut-off step S05 are forcibly executed.

[0028] Because the detection system 1 is equipped with a gas detection camera 3, it can detect leaking gas without waiting for the time it takes for the leaking gas to convect and reach the gas detector 2. The detection system 1 can issue a preliminary alarm D1 at a relatively early stage after the start of a gas leak, which is advantageous for improving the speed at which leaking gas is detected.

[0029] The detection system 1 can widen the detection range of leaked gas depending on the angle of view of the gas detection camera 3. This makes it possible to detect leaked gas over a wider range than the gas detector 2. This is advantageous for widening the detection range of leaked gas.

[0030] The detection system 1 can detect leaked gases with relatively low concentrations that cannot be detected by the gas detection camera 3 using the gas detector 2. By combining the gas detection camera 3 and the gas detector 2, the detection system 1 can detect leaked gases with relatively low concentrations. This is advantageous in preventing a decrease in the accuracy of leaked gas detection.

[0031] When the preliminary alarm D1 is issued, a decision is made as to whether or not to evacuate the crew or cut off the liquefied gas supply. As a result, with the improvement in the speed and range of gas leakage detection, the detection system 1 can avoid problems such as frequent evacuation alarms D2 and supply cutoffs D3, which would make ship navigation inefficient.

[0032] The gas detection camera 3 may include an acoustic camera (ultrasonic gas leak detector). The acoustic camera is configured to detect ultrasonic waves of a specific frequency generated from the gas leak location. It can be said that the acoustic camera can detect the position where the ultrasonic waves are generated based on the image.

[0033] The gas detection camera 3 may include a temperature camera (thermography camera). The temperature camera is configured to capture an image of the temperature distribution. When there is a temperature difference between the leaking gas and the surrounding atmosphere, the temperature camera can more easily detect the leaking gas based on the image of the temperature distribution.

[0034] An acoustic camera or a thermal camera may be used instead of an infrared camera as the gas detection camera 3. Also, any combination of an infrared camera, an acoustic camera, and a thermal camera may be used as the gas detection camera 3.

[0035] For example, when detecting leaked gas using a combination of an infrared camera and a thermal camera, if the temperature of the surrounding atmosphere differs from the temperature of the leaked gas, it becomes easier to detect the leaked gas from this temperature difference. The presence or absence and extent of leaked gas can be detected based on two images from the infrared camera and the thermal camera, improving the accuracy of leaked gas detection. Similarly, by combining an infrared camera with an acoustic camera, an acoustic camera with a thermal camera, or an infrared camera, an acoustic camera, and a thermal camera, the presence or absence and extent of leaked gas can be detected based on multiple images, further improving the accuracy of leaked gas detection.

[0036] As shown in Fig. 3, the gas detector 2 may be configured to be placed near an evacuation route. Fig. 3 shows an example of an onboard layout near the stern of a ship. In this embodiment, one or more gas detectors 2 are installed on the ship along the evacuation route indicated by the arrow. "Near the evacuation route" refers to the area around the route that crew members would use to evacuate in the event of a gas leak. Specifically, the gas detector 2 is installed on the ceiling or wall above the evacuation route.

[0037] With this configuration, the detection system 1 can detect the presence or absence of gas in the evacuation route using the gas detector 2. After confirming the safety of the evacuation route, crew members can evacuate using this evacuation route. This is advantageous for improving crew safety during evacuation. Even if a gas leak occurs in another location, crew members can pass through evacuation routes that the leaked gas has not reached. Even gas detectors 2 that do not react until the leaked gas reaches them can be effectively used to determine whether or not to evacuate.

[0038] Similarly, the gas detection camera 3 may be configured to be placed near the evacuation route. This makes it possible to detect the extent of leaked gas along the evacuation route. If there is leaked gas along the evacuation route but the extent is relatively small, it may be possible for crew members to pass through. Based on the information obtained from the gas detection camera 3, it is determined whether or not crew members can pass through.

[0039] The gas detection camera 3 may be arranged near a location where gas leakage is likely to occur, such as near a connection between gas-passing pipes, making it possible to detect gas leakage in an extremely short time.

[0040] 4, the control mechanism 4 may be composed of a first control mechanism 4a that receives a signal from the gas detection camera 3 and a second control mechanism 4b that receives a signal from the gas detector 2. In this case, the detection system 1 is configured to include two independent control mechanisms 4a and 4b.

[0041] In this embodiment, the first control mechanism 4a has an alarm unit 5 and a first command unit 8a. The first command unit 8a is configured to issue a command when an external signal is input. The first command unit 8a may include a button for a crew member to perform a button operation D4.

[0042] The second control mechanism 4b has a notification unit 6, a shutoff unit 7, and a second command unit 8b. The second command unit 8b is configured to issue a command when the gas detector 2 detects a gas whose concentration exceeds a preset threshold value.

[0043] When a button operation D4 is performed in the first command unit 8a (determination step S02), a command is sent from the first control mechanism 4a to the second control mechanism 4b. This command is sent to at least one of the notification unit 6 and the interruption unit 7 of the second control mechanism 4b.

[0044] The detection system 1 can be realized by adding the gas detection camera 3 and the first control mechanism 4a to an existing ship that is already equipped with the gas detector 2 and the second control mechanism 4b. Because the first control mechanism 4a and the second control mechanism 4b are independent, it is easy to add the first control mechanism 4a without affecting the second control mechanism 4b. For example, if the second control mechanism 4b is incorporated into the ship's control device, the first control mechanism 4a incorporated into a PC or the like can be installed separately on the ship. For new ships, either the detection system 1 shown in Figure 1 or Figure 4 can be easily adopted.

[0045] The notification unit 6 and the cutoff unit 7 are not limited to being included in the second control mechanism 4b, but may be included in the first control mechanism 4a.

[0046] As shown in FIG. 4, the first control mechanism 4a may include an image generator 9 that generates a composite image D5 of the ship's interior layout and the gas leak location based on the signal received from the gas detection camera 3.

[0047] The first control mechanism 4a may have the image generation unit 9. When the detection system 1 includes one control mechanism 4 as in the embodiment illustrated in FIG.

[0048] FIG. 5 shows an example of a composite image D5 generated by the image generation unit 9. The location and range of a gas leak are detected from the image from the gas detection camera 3. The image generation unit 9 generates a composite image D5 that includes an interior layout map and the range of the leaked gas, which is displayed as, for example, a cloud shape 10. The image generation unit 9 is configured to display the generated composite image D5 on, for example, a monitor. The first control mechanism 4a may be configured to transmit the composite image D5 to a mobile terminal carried by a crew member. The image generation unit 9 may be configured to constantly generate and display the composite image D5, or may be configured to generate and display the composite image D5 when a preliminary alarm D1 is issued. It is desirable that the composite image D5 be updated at a predetermined time interval.

[0049] The configuration including the image generation unit 9 allows the crew to easily grasp the location and range of the leaked gas based on the composite image D5. This makes it easier for the crew to select a safe evacuation route based on the composite image D5. This is advantageous for improving the safety of the crew.

[0050] As shown in FIG. 4, the image generating unit 9 may have a configuration that generates a composite image D5 of the ship's interior layout and the leak location based on a signal received from the gas detector 2 in addition to the gas detection camera 3.

[0051] Fig. 6 shows an example of a composite image D5 generated by the image generation unit 9 of this embodiment. The range of leaked gas determined based on the image from the gas detection camera 3 is displayed in the composite image D5 as a cloud shape 10. The location of the gas leak is detected from the installation position of one of the multiple gas detectors 2 that detected the gas. The leak location detected based on the gas detector 2 is displayed in the composite image D5 as a circle 11, for example.

[0052] The image generation unit 9 generates a composite image D5 based on signals received from the gas detector 2 in addition to the gas detection camera 3. By using the gas detector 2, the presence of leaked gas (circle 11) with a relatively low concentration can be included in the composite image D5, although the detectable range is limited. The crew can select a safer evacuation route based on this composite image D5. This is advantageous for improving crew safety. [Explanation of symbols]

[0053] 1. Detection System 2 Gas detectors 3 Gas detection cameras 4 Control Mechanism 4a First control mechanism 4b Second control mechanism 5 Alarm section 6 Notification Department 7. Breaker 8 Command Department 8a First Command Department 8b Second Command Department 9 Image generation unit 10 cloud shape 11 Round D1 Preliminary alarm D2 Evacuation warning D3 Supply cutoff D4 Button Operation D5 Composite Image S01 Pre-alarm step S02 Decision Step S03 Command step S04 Evacuation Steps S05 Shut-off step S06 Repair Steps S07 Recovery Steps

Claims

1. A detection system equipped with a gas detector and installed on a ship, a gas detection camera that determines the presence of gas based on an image; and a control mechanism that receives signals from the gas detector and the gas detection camera, The control mechanism is characterized by having an alarm unit that issues a preliminary alarm when the gas detection camera detects gas, a command unit that sends a command when the concentration of gas detected by the gas detector exceeds a predetermined threshold value or when a signal is received from outside, a notification unit that notifies the ship of the occurrence of a gas leak after the preliminary alarm has been issued and when the command is received, and a cut-off unit that cuts off the supply of liquefied gas after the preliminary alarm has been issued and when the command is received.

2. 10. The detection system of claim 1, wherein the gas detection camera comprises an infrared camera.

3. 10. The detection system of claim 1, wherein the gas detection camera comprises a thermal camera.

4. The detection system according to claim 1 , wherein the gas detector is configured to be placed near an evacuation route.

5. 2. The detection system according to claim 1, wherein the control mechanism includes an image generating unit that generates a composite image of a ship interior layout and a leak location based on a signal received from the gas detection camera.

6. 2. The detection system according to claim 1, wherein the control mechanism includes an image generating unit that generates a composite image of a ship interior layout and a leak location based on signals received from the gas detection camera and signals received from the gas detector.

7. 7. The detection system according to claim 1, wherein the control mechanism comprises a first control mechanism that receives a signal from the gas detection camera, and a second control mechanism that receives a signal from the gas detector.

8. A detection method for detecting gas leaks using a gas detector pre-installed on a ship, comprising: a gas detection camera that determines the presence of gas based on an image; and a control mechanism that receives signals from the gas detector and the gas detection camera, a preliminary alarm step of issuing a preliminary alarm when the gas detection camera detects a gas leak; a command step of transmitting a command when the concentration of the gas detected by the gas detector exceeds a preset threshold value or when a signal is received from an external device; an evacuation step of notifying the inside of the ship of the occurrence of a gas leak when the preliminary alarm has been issued and the command has been received; a shutoff step of shutting off the supply of liquefied gas when the command is received after the preliminary alarm has been issued.

9. a repair step of taking action against the gas leak after the preliminary alarm is issued and if the command is not received; The detection method according to claim 8, further comprising a recovery step of canceling the preliminary alarm after the repair step.

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