Fiber bragg grating gas transmission pipeline monitoring device

Abstract

The utility model relates to a fiber bragg grating gas transmission pipeline monitoring device, and relates to the field of gas transmission pipeline monitoring technology, the fiber bragg grating gas transmission pipeline monitoring device comprises a housing filled with nitrogen, the housing is installed at the joint of two pipelines, two ends of the housing are respectively communicated with connecting pipe parts, and the two connecting pipe parts are respectively installed at the outer sides of the two pipelines in a sealing manner; a gas inlet and outlet connector used for being connected with a vacuumizing device and a nitrogen charging device is fixedly installed on the housing, and a first electromagnetic valve is installed on the gas inlet and outlet connector. A leak detection fiber grating sensor is fixedly installed in the housing and comprises a detection fiber, the detection fiber is located in the housing, and a grating is engraved on the detection fiber. According to the invention, the position where gas leakage easily occurs on the gas transmission pipeline can be monitored, and an alarm can be timely and rapidly given when the gas leakage occurs at the position.

Description

Technical Field

[0001] The present application relates to the field of gas pipeline monitoring technology, and in particular to a fiber grating gas pipeline monitoring device. Background Art

[0002] Pipeline systems used to transport water, gas, oil and other media have become an important part of daily life and economic development. Pipeline leakage seriously affects people's lives and causes economic losses; oil and gas pipeline leakage not only causes significant property losses, but also causes environmental pollution, fires, explosions and other disasters, threatening social security.

[0003] In the prior art, a fiber Bragg grating monitoring system is often used to monitor gas pipelines. The fiber Bragg grating monitoring system mainly includes a temperature measuring optical cable fixedly installed on the pipeline by a clamp, and a number of fiber Bragg gratings are connected in series in the temperature measuring optical cable. One end of the temperature measuring optical cable is connected to an external light source, and the other end of the temperature measuring optical cable is connected to a demodulator, which is electrically connected to a control host in a control room. During the gas pipeline monitoring process, if there is a leak in the gas pipeline, the leaked gas will cause the temperature around the gas pipeline to change, and the gas leak position in the gas pipeline can be determined by observing the position of the abnormal temperature.

[0004] However, the sensitivity of the temperature-sensing optical cable is low, and it can usually only detect gas leakage when the amount of gas leakage in the gas pipeline is large. At locations where gas leakage is prone to occur, such as the connection points of the gas pipeline, the amount of gas leakage cannot be measured quickly and timely in the early stages of gas leakage, and there is room for improvement. Utility Model Content

[0005] In order to improve the accuracy and sensitivity of a fiber Bragg grating monitoring system in monitoring locations prone to leakage, such as pipeline connections in a gas pipeline, the present application provides a fiber Bragg grating gas pipeline monitoring device.

[0006] The present application provides a fiber Bragg grating gas pipeline monitoring device that adopts the following technical solution:

[0007] A fiber Bragg grating gas pipeline monitoring device, comprising a housing filled with nitrogen, the housing being installed at the connection of two pipelines, two ends of the housing being connected and provided with connecting pipes, the two connecting pipes being respectively installed on the outside of the two pipelines in a sealed manner;

[0008] The housing is fixedly provided with an inlet and outlet gas joint for connecting with a vacuum pumping device and a nitrogen charging device, and a first solenoid valve is installed on the inlet and outlet gas joint;

[0009] A leak detection fiber Bragg grating sensor is fixedly installed in the housing, the leak detection fiber Bragg grating sensor comprises a detection fiber, the detection fiber is located inside the housing, a grating is engraved on the detection fiber, and the outer wall of the detection fiber (141) is coated with a gas-sensitive coating that expands when absorbing leaking gas;

[0010] One end of the leak detection fiber grating sensor is connected to a single-mode optical fiber (142), and the single-mode optical fiber (142) is connected to a demodulator via an optical coupler;

[0011] The demodulator is electrically connected to an alarm module, which is installed in a control room. The alarm module is used to alarm when the concentration of leaked gas in the housing exceeds a set value.

[0012] By adopting the above technical solution, after the pipeline is installed, the operator can connect the vacuum device through the air inlet and outlet pipes on the cover to extract the air in the cover; after the air in the cover is extracted, the operator can connect the air inlet and outlet pipes to the nitrogen filling device to fill the cover with an appropriate amount of nitrogen. The nitrogen in the cover is an inert gas, which can avoid the safety hazard caused by the reaction with the gas when the gas leaks at the connection between the two pipes. When the gas in the gas pipeline leaks through the connection between the two pipes, the leaked gas is collected in the cover, and the leaked gas molecules cause the refractive index of the optical fiber to change. After demodulation by the demodulator, the technical effect of detecting the concentration of the leaked gas in the cover can be achieved. The alarm module compares the rising speed of the leaked gas concentration. When the leaked gas concentration exceeds the set value, the alarm module alarm can prompt the monitoring personnel in the control room that there is a gas leak at the connection point, and can promptly prompt the monitoring personnel of the gas leak at the early stage of the gas leak at the connection between the two pipes. Compared with the method of monitoring the temperature change around the pipeline, it can be more accurate and faster.

[0013] Preferably, the alarm module comprises:

[0014] A first comparator is connected to the signal output terminal of the demodulator, and is used to compare the concentration of the leaked gas and output an alarm control signal when the concentration of the leaked gas exceeds a set value;

[0015] The sound and light alarm is fixedly installed in the control room, located beside the control host, and its signal input terminal is connected to the signal output terminal of the first comparator, and is used to receive the alarm control signal and emit a warning sound and flash.

[0016] By adopting the above technical solution, through the first comparator, when the concentration of the leaked gas in the cover exceeds the set concentration value, the first comparator controls the sound and light alarm to emit a warning sound and flash, which can remind the monitoring personnel in the control room that the gas is leaking.

[0017] Preferably, an air pressure sensor is fixedly mounted on the cover, the sensing end of the air pressure sensor extends into the inner cavity of the cover, and the air pressure sensor detects the internal pressure of the cover and outputs an air pressure signal;

[0018] A display is fixedly mounted on the outside of the housing, a signal input end of the display is signal-connected to a signal output end of the air pressure sensor, and the display receives and displays the air pressure signal.

[0019] By adopting the above technical solution, when the operator extracts the air in the cover or fills the cover with nitrogen, the internal air pressure information of the cover can be obtained through the display. When extracting air, the extraction of air can be stopped when the internal air pressure of the cover decreases to the set pressure. When filling nitrogen, the filling of nitrogen can be stopped when the internal air pressure of the cover increases to the set pressure, which effectively improves the convenience of the operator in extracting air from the cover and filling nitrogen into the cover.

[0020] Preferably, a pressure relief pipe is fixedly installed at the bottom of the housing, the pressure relief pipe communicates with the space inside and outside the housing, and a second solenoid valve is installed on the pressure relief pipe;

[0021] The signal output terminal of the air pressure sensor is connected to a second comparator, which receives the air pressure signal and outputs a pressure relief control signal when the air pressure inside the housing is greater than a set value;

[0022] The signal input terminal of the second solenoid valve is signal-connected to the signal output terminal of the second comparator, and the second solenoid valve receives the pressure relief control signal and conducts the pressure relief pipeline.

[0023] By adopting the above technical solution, when too much gas leaks from the cover and the gas pressure inside the cover is greater than the set pressure value, the second comparator controls the second solenoid valve to open the pressure relief pipe, so that the gas in the cover can be discharged, thereby reducing the situation where the cover is damaged due to excessive gas pressure inside the cover.

[0024] In summary, the fiber Bragg grating gas pipeline monitoring device of the present application has at least one of the following beneficial technical effects:

[0025] 1. Through the mutual coordination and use of the cover, the leak detection fiber Bragg grating sensor, the demodulator and the alarm module, when there is a gas leak at the connection between the two pipelines, the leaked gas is collected in the cover. When the leaked gas concentration in the cover reaches the set value, the leak detection fiber Bragg grating sensor, the demodulator and the alarm module can alarm and prompt the relevant personnel in the control room to leak the gas at the monitored position. The gas leak at the connection in the transmission pipeline can be found in time when the gas leakage is small and in the early stage of gas leakage, which can effectively improve the efficiency of gas leak detection at the pipeline connection;

[0026] 2. When too much gas leaks from the cover and the gas pressure inside the cover is greater than the set pressure value, the second comparator controls the second solenoid valve to connect the pressure relief pipe to discharge the gas in the cover, thereby reducing the situation where the cover is damaged due to excessive gas pressure inside the cover. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of an embodiment of the present application for illustrating the overall structure of a monitoring device.

[0028] Figure 2 It is a schematic diagram of an embodiment of the present application for demonstrating the internal signal transmission of a monitoring device.

[0029] Explanation of the reference numerals: 1. cover shell; 11. connecting pipe; 12. air inlet and outlet pipes; 13. first solenoid valve; 14. leak detection fiber grating sensor; 141. detection optical fiber; 142. input optical cable; 15. air pressure sensor; 16. display; 17. pressure relief pipe; 18. second solenoid valve; 2. pipe; 3. optical coupler; 4. transmission optical cable; 5. demodulator; 6. alarm module; 7. light source. DETAILED DESCRIPTION

[0030] The following is combined with Figure 1-2 This application is described in further detail.

[0031] Example

[0032] The present application embodiment discloses a fiber Bragg grating gas pipeline monitoring device. Figure 1 , including a housing 1 filled with nitrogen, the housing 1 is installed at the connection of two pipes 2, both ends of the housing 1 are connected with connecting pipe parts 11, and the two connecting pipe parts 11 are sealed and installed on the outside of the two pipes 2 respectively.

[0033] It should be noted that, in the embodiment of the present application, the ends of the two connecting pipe portions 11 are respectively installed on the outer side walls of the two pipes by welding and sealing, and the gas flowing in the two pipes is hydrogen, and a sealed space is formed in the cover shell 1.

[0034] Reference Figure 1 The housing 1 is fixedly provided with an inlet and outlet gas joint for connecting with a vacuum pumping device and a nitrogen charging device, and a first solenoid valve 13 is installed on the inlet and outlet gas joint.

[0035] Reference Figure 1 and Figure 2A leak detection fiber Bragg grating sensor 14 is fixedly installed in the housing 1. The leak detection fiber Bragg grating sensor 14 is connected to a single-mode optical fiber 141, the input end of the single-mode optical fiber 141 is connected to a light source 7, the single-mode optical fiber 141 is connected to a demodulator 5 through an optical coupler 3 and a transmission optical cable 4, the demodulator 5 is electrically connected to an alarm module 6, the alarm module 6 is installed in the control room, and the alarm module is used to alarm when the concentration of the leaked gas in the housing 1 exceeds a set value.

[0036] The leak detection fiber grating sensor 14 includes a detection fiber 141 extending into the housing 1. The detection fiber 141 is engraved with a grating and a gas-sensitive coating which expands after absorbing leaked gas and causes strain pressure on the detection fiber.

[0037] The rising speed of the leakage gas concentration is compared through the alarm module 6. When the leakage gas concentration exceeds the set value, the alarm module 6 can alert the monitoring personnel in the control room that there is a gas leakage at the connection point. The monitoring personnel can be promptly alerted of the gas leakage at the connection between the two pipelines at the early stage of the gas leakage. Compared with the method of monitoring the temperature changes around the pipeline, it can be more accurate and faster.

[0038] When the pipeline is installed, the operator can connect the vacuum device through the air inlet and outlet pipes 12 on the cover shell 1 to extract the air in the cover shell 1; after the air in the cover shell 1 is extracted, the operator can connect the air inlet and outlet pipes 12 to the nitrogen filling device to fill a proper amount of nitrogen into the cover shell 1. The nitrogen in the cover shell 1 is an inert gas, which can avoid the safety hazard caused by the reaction with the gas when the gas leaks at the connection between the two pipes, and at the same time, a relatively stable and pure space can be formed in the cover shell 1.

[0039] It should be noted that since the leakage gas to be detected in the embodiment of the present application is hydrogen, the gas-sensitive coating adopts a palladium film with a thickness of 230.65nm. After the palladium film absorbs hydrogen, the pressure applied to the outer wall of the detection optical fiber changes, and the reflection wavelength of the optical fiber emitted by the light source changes after passing through the grating. After demodulation by the demodulator, the concentration value of hydrogen can be measured and the leakage gas concentration signal can be output. Since a hydrogen concentration exceeding 4% is likely to cause deflagration, the alarm module can sound an alarm when the hydrogen concentration exceeds 4%.

[0040] In some other embodiments, different types of gas-sensitive coatings may be provided on the detection optical fiber according to different types of leaked gas to be detected, which is not limited here.

[0041] Reference Figure 2In the embodiment of the present application, the alarm module 6 includes: a first comparator, which is signal-connected to the signal output terminal of the demodulator, used to receive the leakage gas concentration signal and compare the leakage gas concentration, and output an alarm control signal when the leakage gas concentration exceeds the set value; an audible and visual alarm, which is fixedly installed in the control room, located next to the control host, and the signal input terminal is signal-connected to the signal output terminal of the first comparator, used to receive the alarm control signal and emit a warning sound and flash.

[0042] Through the first comparator, when the concentration of the leaked gas in the housing 1 exceeds the set concentration value, the first comparator controls the sound and light alarm to emit a warning sound and flash, which can remind the monitoring personnel in the control room that there is a gas leak.

[0043] Reference Figure 1 and Figure 2 A pressure sensor 15 is fixedly mounted on the cover 1, and the sensing end of the pressure sensor 15 extends into the inner cavity of the cover 1. The pressure sensor 15 detects the internal pressure of the cover 1 and outputs a pressure signal. A display 16 is fixedly mounted on the outside of the cover 1, and the signal input end of the display 16 is connected to the signal output end of the pressure sensor 15. The display 16 receives the pressure signal and displays it.

[0044] When the operator extracts the air in the cover 1 or fills the cover 1 with nitrogen, the internal air pressure information of the cover 1 can be obtained through the display 16. When extracting air, the extraction of air can be stopped when the internal air pressure of the cover 1 decreases to a set pressure. When filling nitrogen, the filling of nitrogen can be stopped when the internal air pressure of the cover 1 increases to a set pressure, which effectively improves the convenience of the operator in extracting air from the cover 1 and filling nitrogen into the cover 1.

[0045] Reference Figure 1 and Figure 2 A pressure relief pipe 17 is fixedly installed at the bottom of the cover shell 1, and the pressure relief pipe 17 connects the space inside and outside the cover shell 1. A second solenoid valve 18 is installed on the pressure relief pipe 17; the signal output end of the air pressure sensor 15 is connected to the second comparator, and the second comparator receives the air pressure signal and outputs a pressure relief control signal when the air pressure inside the cover shell 1 is greater than the set value; the signal input end of the second solenoid valve 18 is connected to the signal output end of the second comparator, and the second solenoid valve 18 receives the pressure relief control signal and conducts the pressure relief pipe 17.

[0046] When too much gas leaks from the housing 1 and the gas pressure inside the housing 1 is greater than the set pressure value, the second comparator controls the second solenoid valve 18 to connect the pressure relief pipe 17 to discharge the gas in the housing 1, thereby reducing the possibility of damage to the housing 1 caused by excessive gas pressure inside the housing 1.

[0047] The implementation principle of a fiber grating gas pipeline monitoring device in an embodiment of the present application is: through the mutual coordination and use of a cover, a leak detection fiber grating sensor, a demodulator and an alarm module, when there is a gas leakage at the connection between two pipelines, the leaked gas is collected in the cover, and the leak detection fiber grating sensor, the demodulator and the alarm module can be used to alarm and prompt the relevant personnel in the control room to know that the gas is leaking at the monitored position when the leakage gas concentration in the cover reaches a set value, so that the gas leakage at the connection in the transmission pipeline can be timely discovered when the gas leakage amount is small and in the early stage of gas leakage, which can effectively improve the efficiency of gas leak detection at the pipeline connection.

[0048] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A fiber Bragg grating gas pipeline monitoring device, characterized in that: The invention comprises a housing (1) filled with nitrogen, the housing (1) being installed at the connection of two pipes (2), the two ends of the housing (1) being connected and provided with connecting pipe parts (11), the two connecting pipe parts (11) being respectively sealed and installed on the outside of the two pipes (2); The housing (1) is fixedly provided with an inlet and outlet gas joint for connecting to a vacuum pumping device and a nitrogen charging device, and a first solenoid valve (13) is installed on the inlet and outlet gas joint; A leak detection fiber grating sensor (14) is fixedly installed in the housing (1), the leak detection fiber grating sensor (14) comprising a detection optical fiber (141), the detection optical fiber (141) being located inside the housing (1), the detection optical fiber (141) being engraved with a grating, and the outer side wall of the detection optical fiber (141) being coated with a gas-sensitive coating that expands upon absorbing leaked gas; One end of the leakage detection fiber grating sensor (14) is connected to a single-mode optical fiber (142), and the single-mode optical fiber (142) is connected to a demodulator (5) via an optical coupler; The demodulator is electrically connected to an alarm module (6), which is installed in a control room. The alarm module (6) is used to sound an alarm when the concentration of leaked gas in the housing (1) exceeds a set value.

2. A fiber Bragg grating gas pipeline monitoring device according to claim 1, characterized in that: The alarm module (6) comprises: A first comparator, connected to the signal output terminal of the demodulator (5), for comparing the concentration of the leaked gas and outputting an alarm control signal when the concentration of the leaked gas exceeds a set value; The sound and light alarm is fixedly installed in the control room, located beside the control host, and its signal input terminal is connected to the signal output terminal of the first comparator, and is used to receive the alarm control signal and emit a warning sound and flash.

3. A fiber Bragg grating gas pipeline monitoring device according to claim 2, characterized in that: An air pressure sensor (15) is fixedly mounted on the housing (1), the sensing end of the air pressure sensor (15) extends into the inner cavity of the housing (1), and the air pressure sensor (15) detects the internal pressure of the housing (1) and outputs an air pressure signal; A display (16) is fixedly mounted on the outside of the housing (1), a signal input end of the display (16) is signal-connected to a signal output end of the air pressure sensor (15), and the display (16) receives the air pressure signal and displays it.

4. A fiber Bragg grating gas pipeline monitoring device according to claim 3, characterized in that: A pressure relief pipe (17) is fixedly installed at the bottom of the housing (1), the pressure relief pipe (17) is connected to the space inside and outside the housing (1), and a second solenoid valve (18) is installed on the pressure relief pipe (17); The signal output terminal of the air pressure sensor (15) is connected to a second comparator, which receives the air pressure signal and outputs a pressure relief control signal when the air pressure inside the housing (1) is greater than a set value; The signal input end of the second solenoid valve (18) is signal-connected to the signal output end of the second comparator, and the second solenoid valve (18) receives the pressure relief control signal and conducts the pressure relief pipeline (17).

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