A distributed optical fiber temperature detection system
The distributed fiber optic temperature detection system solves the problems of incomplete monitoring coverage and complex wiring of traditional single-point temperature sensors in LNG pipelines, achieving all-round temperature monitoring, improving monitoring accuracy and system stability, reducing costs and failure points, and ensuring the safe and efficient operation of the pipeline.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JINAGSU SUNPOWER PIPELINE ENG TECH CO LTD
- Filing Date
- 2025-08-25
- Publication Date
- 2026-06-09
Smart Images
Figure CN224341086U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of liquefied natural gas (LNG) pipeline safety monitoring technology, and in particular to a distributed optical fiber temperature detection system. Background Technology
[0002] In today's industrial and energy sectors, LNG, as a clean and efficient energy source, is playing an increasingly important role in global energy consumption. The safe and timely commissioning of LNG receiving terminals is crucial for their stable and efficient operation. Currently, LNG transmission pipelines primarily rely on traditional monitoring methods for pre-cooling control and long-term safe operation during transmission.
[0003] Traditional temperature monitoring typically employs single-point temperature sensors. These sensors work by using internal thermistor elements, such as thermocouples or resistance temperature detectors (RTDs), to convert temperature changes into electrical signals for measurement. Structurally, each sensor has its own independent signal line and interface, which are connected to the monitoring system via wiring.
[0004] In applications, these sensors are distributed and installed at critical locations on pipelines to acquire temperature data. However, conventional infrared thermal imagers are limited by detection distance and environmental interference, making them unsuitable for long-term online monitoring in complex environments such as pipe racks.
[0005] Problems and shortcomings of existing technologies.
[0006] 1. Incomplete monitoring coverage: Traditional single-point temperature sensors can only obtain temperature information at the installation point, and cannot achieve full coverage monitoring of the pipeline. There are a lot of monitoring blind spots, making it difficult to detect potential hazards such as cracks and cold leakage at locations in the pipeline where the temperature sensor is not installed.
[0007] 2. Complex wiring: Each temperature sensor requires a signal line and interface. In large-scale pipeline monitoring, the wiring project is cumbersome, costly, and difficult to troubleshoot. Due to the large number of lines, problems such as line aging and poor contact are also prone to occur, affecting the stability and accuracy of monitoring.
[0008] 3. Unable to reconstruct the three-dimensional temperature field of the insulation layer and unable to accurately locate the source of cold leakage: Traditional temperature measurement often measures the temperature data of fixed points in the circuit, which is difficult to respond to cold leakage in a timely manner and requires manual on-site determination of the source of cold leakage. Utility Model Content
[0009] The purpose of this invention is to provide a distributed fiber optic temperature detection system to address the shortcomings of traditional single-point temperature sensors in monitoring LNG pipelines.
[0010] To solve the above-mentioned technical problems, this utility model provides a distributed optical fiber temperature detection system, including a sensing optical fiber arranged along the length of the low-temperature pipeline;
[0011] A laser source and an optical signal pulse amplifier are provided at the end of the sensing fiber. The laser emitted by the laser source is amplified by the optical signal pulse amplifier and then enters the sensing fiber, where Raman scattering occurs at various positions of the sensing fiber.
[0012] The end of the sensing fiber is also equipped with a data acquisition module, an APD photoelectric conversion module, and a wavelength division multiplexer. After the laser is scattered in the sensing fiber, it will form echo signals of Stokes light and anti-Stokes light of different wavelengths. The echo signals of the sensing fiber are converted by the wavelength division multiplexer and the APD photoelectric conversion module and then enter the data acquisition module. The data acquisition module acquires the light intensity signals of at least two beams of light. Based on the principle that the light intensity is different at different temperatures, the temperature of the reflection point is obtained by analyzing the light intensity changes.
[0013] Preferably, an acousto-optic modulator is provided between the laser source and the optical signal pulse amplifier. The acousto-optic modulator rapidly switches the on / off state of the laser through a radio frequency drive signal to form a high-contrast pulse output.
[0014] Preferably, the cryogenic pipeline is sequentially wrapped with an inner cold insulation layer, an intermediate cold insulation layer, and an outer cold insulation layer.
[0015] Preferably, at least two sensing optical fibers are laid between the low-temperature pipeline and the inner insulation layer.
[0016] Preferably, two sensing optical fibers are arranged between the cryogenic pipe and the inner insulation layer, located at the upper and lower apexes of the cryogenic pipe, respectively.
[0017] Preferably, at least two sensing optical fibers are arranged inside the outer cold insulation layer.
[0018] Preferably, three sensing optical fibers are arranged inside the outer cold insulation layer, one of which is located at the top vertex of the outer cold insulation layer, the second sensing optical fiber is offset by 45° relative to the first one, and the third sensing optical fiber is offset by 135° relative to the third one.
[0019] Preferably, the two sensing optical fibers between the low-temperature pipeline and the inner cold insulation layer are armored temperature measuring optical fibers formed by sheathing stainless steel pipes.
[0020] Preferably, the two sensing optical fibers arranged inside the outer cold insulation layer are ordinary temperature measuring optical fibers.
[0021] Compared with the prior art, the beneficial effects of this utility model are:
[0022] 1. This temperature detection system adopts distributed fiber optic temperature measurement technology to achieve full-length, all-round temperature monitoring of LNG pipelines, effectively eliminating monitoring blind spots and timely detecting potential hazards such as cracks and cold leakage at any location in the pipeline, greatly improving the accuracy and reliability of monitoring;
[0023] 2. This temperature detection system completes the temperature measurement loop through optical fiber, which significantly reduces the number of wires compared to traditional single-point sensors, lowering wiring costs and construction difficulty. Simultaneously, it reduces potential line fault points, decreases maintenance workload and costs, and improves the stability of the monitoring system.
[0024] 3. This distributed fiber optic temperature detection system can monitor the temperature difference between the upper and lower surfaces of the LNG pipeline in real time, effectively preventing bending deformation and thermal stress damage caused by excessively rapid pipeline cooling. Through analysis of multi-dimensional data such as pipeline energy efficiency and insulation condition, it provides a scientific basis for pipeline maintenance and operation optimization, assisting operators in making more rational decisions and ensuring the safe and efficient operation of the pipeline. Attached Figure Description
[0025] Figure 1 This is a diagram of a distributed optical fiber temperature detection system provided by this utility model;
[0026] Figure 2 This is a schematic diagram of the radial arrangement of optical fibers in low-temperature pipelines and insulation layers provided by this utility model;
[0027] Figure 3 This is a schematic diagram of the structure of the armored temperature measuring optical fiber provided by this utility model.
[0028] In the diagram: 10. Low-temperature pipeline; 1. Sensing fiber; 101 stainless steel pipe; 2. Laser source; 3. Optical signal pulse amplifier; 4. Data acquisition module; 5. APD photoelectric conversion module; 6. Wavelength division multiplexer; 7. Acousto-optic modulator; 10. Low-temperature pipeline; 20. Inner cold insulation layer; 30. Middle cold insulation layer; 40. Outer cold insulation layer. Detailed Implementation
[0029] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.
[0030] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0031] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Example
[0032] This utility model provides a distributed optical fiber temperature detection system. Please refer to [link / reference]. Figure 1 The system includes a sensing fiber 1 laid along the length of the cryogenic pipeline 10; a laser source 2 and an optical signal pulse amplifier 3 are provided at the end of the sensing fiber 1. Temperature measurement is performed based on the spontaneous Raman scattering effect of the optical fiber, and spatial positioning is performed using optical time domain reflectance (OTDR) technology. Specifically, the laser emitted by the laser source 2 is amplified by the optical signal pulse amplifier 3 and then enters the sensing fiber 1, where Raman scattering occurs at various locations. The end of the sensing fiber 1 is also provided with a data acquisition module 4, an APD photoelectric conversion module 5, and a wavelength division multiplexer 6. After the laser is scattered in the sensing fiber 1, it forms echo signals of Stokes light and anti-Stokes light of different wavelengths. The echo signals of the sensing fiber 1 are converted by the wavelength division multiplexer 6 and the APD photoelectric conversion module 5 and then enter the data acquisition module 4. The data acquisition module 4 acquires the light intensity signals of at least two beams of light. Based on the principle that the light intensity is different at different temperatures, the temperature of the reflection point is obtained by analyzing the changes in light intensity.
[0033] In this embodiment, the laser source 2 is GY-LASER-1550-30, the optical signal pulse amplifier 3 is GY-EDFA-RA, the data acquisition module 4 is GY-DTS-200-DAQ, the APD photoelectric conversion module 5 is APD22-100M, and the wavelength division multiplexer 6 is Ouyi Optoelectronics 1x3 Raman WDM.
[0034] Specifically, an acousto-optic modulator 7 is provided between the laser source 2 and the optical signal pulse amplifier 3. The acousto-optic modulator 7 rapidly switches the on / off state of the laser through a radio frequency drive signal to form a high-contrast pulse output.
[0035] This temperature detection system employs distributed fiber optic temperature measurement technology to achieve full-length, all-around temperature monitoring of LNG pipelines, effectively eliminating monitoring blind spots and enabling timely detection of potential hazards such as cracks and cold leaks at any location within the pipeline, significantly improving the accuracy and reliability of monitoring. Compared to traditional single-point sensors, it greatly reduces the number of wires, lowering wiring costs and construction difficulty. Simultaneously, it reduces potential line failure points, decreasing maintenance workload and costs, and improving the stability of the monitoring system.
[0036] Specifically, such as Figure 2 As shown, the cryogenic pipe 10 is sequentially wrapped with an inner cold insulation layer 20, a middle cold insulation layer 30, and an outer cold insulation layer 40.
[0037] Furthermore, at least two sensing optical fibers 1 are arranged between the cryogenic pipe 10 and the inner insulation layer 20. In this embodiment, the two sensing optical fibers 1 are located at the upper and lower vertices of the cryogenic pipe 10, respectively, and are used to monitor the temperature difference between the upper and lower surfaces of the cryogenic pipe 10.
[0038] Furthermore, three sensing optical fibers 1 are arranged inside the outer cold insulation layer 40, one of which is located at the upper vertex of the outer cold insulation layer 40, the second sensing optical fiber 1 is offset by 45° relative to the first one, and the third sensing optical fiber 1 is offset by 135° relative to the third one, so as to realize the all-round temperature monitoring of the outer cold insulation layer 40.
[0039] This temperature detection system uses optical fiber to complete the temperature measurement loop, which significantly reduces the number of wires compared to traditional single-point sensors, lowering wiring costs and construction difficulty. At the same time, it reduces potential line failure points, decreases maintenance workload and costs, and improves the stability of the monitoring system.
[0040] In this embodiment, depending on the temperature, for the extreme low temperature condition of the inner layer (<-100°), the two sensing optical fibers 1 between the low temperature pipeline 10 and the inner cold insulation layer 20 are made of stainless steel pipe 101 to form armored temperature measuring optical fibers, which have good mechanical strength, waterproof, leak-proof and good thermal conductivity, and are suitable for monitoring low temperature LNG pipelines.
[0041] In this embodiment, under non-extreme low temperature conditions (>-100°C) of the outer layer, the two sensing optical fibers 1 arranged inside the outer cold insulation layer 40 only need to be ordinary temperature measuring optical fibers that meet the measurement requirements.
[0042] This distributed fiber optic temperature monitoring system can monitor the temperature difference between the upper and lower surfaces of LNG pipelines in real time, effectively preventing bending deformation and thermal stress damage caused by excessively rapid pipeline cooling. Through analysis of multi-dimensional data such as pipeline energy efficiency and insulation condition, it provides a scientific basis for pipeline maintenance and operational optimization, assisting operators in making more rational decisions and ensuring the safe and efficient operation of the pipeline.
[0043] The above description is only a description of the preferred embodiment of the present utility model and is not intended to limit the scope of the present utility model in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.
Claims
1. A distributed optical fiber temperature detection system, characterized in that, Including sensing optical fibers (1) laid along the length of the cryogenic pipe (10); The end of the sensing fiber (1) is provided with a laser source (2) and an optical signal pulse amplifier (3). The laser emitted by the laser source (2) is amplified by the optical signal pulse amplifier (3) and enters the sensing fiber (1), and Raman scattering occurs at various positions of the sensing fiber (1). The end of the sensing fiber (1) is also provided with a data acquisition module (4), an APD photoelectric conversion module (5) and a wavelength division multiplexer (6). After the laser is scattered in the sensing fiber (1), it will form echo signals of Stokes light and anti-Stokes light of different wavelengths. The echo signals of the sensing fiber (1) are converted by the wavelength division multiplexer (6) and the APD photoelectric conversion module (5) and then enter the data acquisition module (4). The data acquisition module (4) acquires the light intensity signals of at least two beams of light. Based on the principle that the light intensity is different at different temperatures, the temperature of the reflection point is obtained by analyzing the change in light intensity.
2. The distributed optical fiber temperature detection system as described in claim 1, characterized in that, An acousto-optic modulator (7) is provided between the laser source (2) and the optical signal pulse amplifier (3). The acousto-optic modulator (7) quickly switches the on / off state of the laser through a radio frequency drive signal to form a high-contrast pulse output.
3. The distributed optical fiber temperature detection system as described in claim 1, characterized in that, The cryogenic pipe (10) is wrapped with an inner cold insulation layer (20), a middle cold insulation layer (30) and an outer cold insulation layer (40) in sequence.
4. The distributed optical fiber temperature detection system as described in claim 3, characterized in that, At least two sensing optical fibers (1) are laid between the low-temperature pipe (10) and the inner cold insulation layer (20).
5. A distributed optical fiber temperature detection system as described in claim 4, characterized in that, Two sensing optical fibers (1) are arranged between the low-temperature pipe (10) and the inner cold insulation layer (20), respectively located at the upper and lower apex of the low-temperature pipe (10).
6. The distributed optical fiber temperature detection system as described in claim 3, characterized in that, At least two sensing optical fibers (1) are arranged inside the outer cold insulation layer (40).
7. The distributed optical fiber temperature detection system as described in claim 6, characterized in that, Three sensing optical fibers (1) are arranged inside the outer cold insulation layer (40), one of which is located at the upper vertex of the outer cold insulation layer (40), the second sensing optical fiber (1) is offset by 45° relative to the first one, and the third sensing optical fiber (1) is offset by 135° relative to the third one.
8. A distributed optical fiber temperature detection system as described in claim 5, characterized in that, The two sensing optical fibers (1) between the low-temperature pipeline (10) and the inner cold insulation layer (20) are armored temperature measuring optical fibers formed by being sheathed with stainless steel pipes (101).
9. A distributed optical fiber temperature detection system as described in claim 7, characterized in that, The two sensing optical fibers (1) arranged inside the outer cold insulation layer (40) are ordinary temperature measuring optical fibers.