Arrangement of linear temperature measuring optical fibers in a pipe

Abstract

The utility model discloses a kind of arrangement structure of linear temperature measuring optical fiber in pipeline, low-temperature pipeline is successively wrapped with inner cold insulation layer, intermediate cold insulation layer and outer cold insulation layer outside;Low-temperature pipeline and inner cold insulation layer between arrangement inner layer temperature measuring optical fiber, to monitor the surface temperature difference of low-temperature pipeline;Outer cold insulation layer is arranged in outer layer temperature measuring optical fiber, to monitor the surface temperature difference of outer cold insulation layer;Inner layer temperature measuring optical fiber and outer layer temperature measuring optical fiber are extended along the length direction of low-temperature pipeline.The utility model completes temperature measuring circuit by optical fiber, compared with traditional single-point sensor, greatly reduce the wiring quantity, reduce wiring cost and construction difficulty.Meanwhile, reduce the line fault point, reduce maintenance workload and maintenance cost, improve the stability of monitoring system.Through the analysis of multidimensional data such as pipeline energy efficiency, cold insulation layer condition, provide scientific basis for the maintenance of pipeline, operation optimization, assist operating personnel to make more reasonable decision, guarantee pipeline safe, efficient operation.

Description

Technical Field

[0001] This utility model relates to the field of liquefied natural gas (LNG) pipeline safety monitoring technology, and in particular to an arrangement structure of linear temperature measuring optical fibers inside a pipeline. 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 an arrangement structure for linear temperature-measuring optical fibers inside a pipeline, so as to solve the defects of traditional single-point temperature sensors in monitoring LNG transmission pipelines.

[0010] To solve the above technical problems, this utility model provides an arrangement structure of a linear temperature measuring optical fiber inside a pipeline. The low-temperature pipeline is wrapped with an inner cold insulation layer, a middle cold insulation layer and an outer cold insulation layer in sequence. An inner layer temperature measuring optical fiber is arranged between the low-temperature pipeline and the inner cold insulation layer to monitor the surface temperature difference of the low-temperature pipeline.

[0011] An outer layer temperature-measuring optical fiber is installed inside the outer cold insulation layer to monitor the surface temperature difference of the outer cold insulation layer;

[0012] Both the inner and outer temperature-sensing optical fibers extend along the length of the cryogenic pipeline.

[0013] Preferably, the inner layer temperature measuring optical fiber has two roots, located at the upper and lower vertices of the low-temperature pipe respectively, and extends along the length direction on the outer wall of the low-temperature pipe.

[0014] Preferably, the outer temperature-sensing optical fiber has three fibers, one of which is located at the top vertex of the outer cold insulation layer, the second outer temperature-sensing optical fiber is offset by 45° relative to the first fiber, and the third outer temperature-sensing optical fiber is offset by 135° relative to the first fiber.

[0015] Preferably, both outer temperature-measuring optical fibers are located on the side of the outer cold insulation layer away from the middle cold insulation layer.

[0016] Preferably, the two inner temperature-measuring optical fibers and the three outer temperature-measuring optical fibers are all connected to the same data acquisition module.

[0017] Preferably, the inner temperature-sensing fiber and the outer temperature-sensing fiber are formed by the same fiber back-through.

[0018] Preferably, the temperature measuring optical fiber first exits along the top vertex side of the outer insulation layer, then deflects back at 45°, then exits along the top vertex side of the low-temperature pipe, then deflects back along the bottom vertex side of the low-temperature pipe, and finally exits at 45°.

[0019] Preferably, the inner temperature-sensing optical fiber is an armored temperature-sensing optical fiber formed by sheathing a circular stainless steel tube.

[0020] Preferably, the inner temperature-sensing optical fiber is an armored temperature-sensing optical fiber formed by an arc-shaped stainless steel cover.

[0021] Compared with the prior art, the beneficial effects of this utility model are:

[0022] This invention utilizes optical fiber to complete the temperature measurement circuit, significantly reducing the number of wires compared to traditional single-point sensors, thus lowering wiring costs and construction difficulty. Simultaneously, it reduces potential line failure points, decreases maintenance workload and costs, and improves the stability of the monitoring system. Furthermore, the optical fiber monitors 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 operational optimization, assisting operators in making more rational decisions and ensuring the safe and efficient operation of the pipeline. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the radial arrangement structure of the linear temperature measuring optical fiber in the pipeline provided by this utility model;

[0024] Figure 2 This is a schematic diagram of the axial arrangement structure of the through-type temperature measuring optical fiber provided by this utility model;

[0025] Figure 3 This is a schematic diagram of the axial arrangement structure of the threadback-type temperature measuring optical fiber provided by this utility model;

[0026] Figure 4 This is a schematic diagram of the structure of the circular stainless steel tube sleeved to form an armored temperature measuring optical fiber provided by this utility model;

[0027] Figure 5 This is a schematic diagram of the structure of the arc-shaped stainless steel cover forming an armored temperature measuring optical fiber provided by this utility model.

[0028] In the diagram: 1. Low-temperature pipeline; 2. Inner cold insulation layer; 3. Middle cold insulation layer; 4. Outer cold insulation layer; 5. Inner temperature measuring fiber optic cable; 6. Outer temperature measuring fiber optic cable; 7. Circular stainless steel pipe; 8. Arc-shaped stainless steel cover; 10. Data acquisition module. 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.

[0032] Example 1

[0033] This utility model provides an arrangement structure for a linear temperature-sensing optical fiber inside a pipeline. Please refer to [link / reference]. Figure 1 The cryogenic pipe 1 is sequentially wrapped with an inner cold insulation layer 2, a middle cold insulation layer 3, and an outer cold insulation layer 4. An inner layer temperature-sensing optical fiber 5 is installed between the cryogenic pipe 1 and the inner cold insulation layer 2 to monitor the surface temperature difference of the cryogenic pipe 1, while an outer layer temperature-sensing optical fiber 6 is installed inside the outer cold insulation layer 4 to monitor the surface temperature difference of the outer cold insulation layer 4. Both the inner layer temperature-sensing optical fiber 5 and the outer layer temperature-sensing optical fiber 6 extend along the length of the cryogenic pipe 1.

[0034] In this embodiment, as Figure 2 As shown, the inner layer temperature measuring optical fiber 5 has two fibers, which are located at the upper and lower vertices of the low-temperature pipe 1 respectively, and extend along the length direction on the outer wall of the low-temperature pipe 1 to monitor the temperature difference between the upper and lower surfaces of the outer insulation layer 4.

[0035] The outer temperature-sensing optical fiber 6 has three fibers, one of which is located at the top vertex of the outer cold insulation layer 4, the second fiber is offset by 45° relative to the first fiber, and the third fiber is offset by 135° relative to the first fiber. Both outer temperature-sensing optical fibers 6 are located on the side of the outer cold insulation layer 4 away from the middle cold insulation layer 3, so as to monitor the temperature of various parts of the outer cold insulation layer 4 in all directions.

[0036] Furthermore, the two inner temperature-measuring optical fibers 5 and the three outer temperature-measuring optical fibers 6 are all connected to the same data acquisition module 10.

[0037] In one embodiment, such as Figure 4 As shown, based on the temperature, for the extreme low temperature conditions of the inner layer (<-100°), the inner layer temperature measuring fiber 5 is formed by a circular stainless steel tube 7 being sheathed to form an armored temperature measuring fiber, which has good mechanical strength, waterproof, leak-proof and good thermal conductivity, and is suitable for low temperature LNG pipeline monitoring.

[0038] In another embodiment, the inner temperature-sensing optical fiber 5 can also be formed by sheathing a circular stainless steel tube 7 to form an armored temperature-sensing optical fiber.

[0039] The actual temperature measurement process is as follows: temperature measurement is based on the spontaneous Raman scattering effect of optical fiber, and spatial positioning is achieved through optical time-domain reflectometry (OTDR) technology. Specifically, the laser emitted by the laser source is amplified by an optical signal pulse amplifier and then enters the temperature-measuring optical fiber, where Raman scattering occurs at various locations. The end of the temperature-measuring optical 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 temperature-measuring optical fiber, it forms echo signals of Stokes light and anti-Stokes light of different wavelengths. The echo signals of the temperature-measuring optical 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 changes in light intensity.

[0040] In this embodiment, the laser source used is GY-LASER-1550-30, the optical signal pulse amplifier is GY-EDFA-RA, the data acquisition module is GY-DTS-200-DAQ, the APD photoelectric conversion module is APD22-100M, and the wavelength division multiplexer is Ouyi Optoelectronics 1x3 Raman WDM.

[0041] Example 2

[0042] In this embodiment, the inner temperature-sensing fiber 5 and the outer temperature-sensing fiber 6 are formed by the same fiber through a loop. Specifically, the temperature-sensing fiber first exits along the upper vertex side of the outer cold insulation layer 4, then loops back at a 45° offset, then exits along the upper vertex side of the low-temperature pipe 1, then loops back along the lower vertex side of the low-temperature pipe 1, and finally exits at a 45° offset.

[0043] This invention utilizes optical fiber to complete the temperature measurement circuit, significantly reducing the number of wires compared to traditional single-point sensors, thus lowering wiring costs and construction difficulty. Simultaneously, it reduces potential line failure points, decreases maintenance workload and costs, and improves the stability of the monitoring system. Furthermore, the optical fiber monitors 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 operational optimization, assisting operators in making more rational decisions and ensuring the safe and efficient operation of the pipeline.

[0044] 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 linear temperature-measuring fiber arrangement structure inside a pipeline, wherein a low-temperature pipeline (1) is sequentially wrapped with an inner cold insulation layer (2), a middle cold insulation layer (3), and an outer cold insulation layer (4); characterized in that, An inner layer temperature measuring optical fiber (5) is installed between the low-temperature pipe (1) and the inner cold insulation layer (2) to monitor the surface temperature difference of the low-temperature pipe (1); An outer layer temperature measuring optical fiber (6) is installed inside the outer cold insulation layer (4) to monitor the surface temperature difference of the outer cold insulation layer (4); Both the inner temperature-measuring fiber (5) and the outer temperature-measuring fiber (6) extend along the length of the low-temperature pipe (1).

2. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 1, characterized in that, The inner layer temperature measuring optical fiber (5) has two roots, located at the upper and lower vertices of the low temperature pipe (1) respectively, and extending along the length direction on the outer wall of the low temperature pipe (1).

3. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 2, characterized in that, The outer temperature measuring fiber (6) has three fibers, one of which is located at the top vertex of the outer cold insulation layer (4), the second outer temperature measuring fiber (6) is offset by 45° relative to the first fiber, and the third outer temperature measuring fiber (6) is offset by 135° relative to the first fiber.

4. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 3, characterized in that, Both outer temperature-measuring optical fibers (6) are located on the side of the outer cold insulation layer (4) away from the middle cold insulation layer (3).

5. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 3, characterized in that, The two inner temperature-measuring optical fibers (5) and the three outer temperature-measuring optical fibers (6) are all connected to the same data acquisition module (10).

6. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 1, characterized in that, The inner temperature-measuring fiber (5) and the outer temperature-measuring fiber (6) are formed by the same fiber back-through.

7. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 6, characterized in that, The temperature measuring fiber first passes out along the upper vertex side of the outer cold insulation layer (4), then passes back at a 45° offset, then passes out along the upper vertex side of the low temperature pipe (1), then passes back along the lower vertex side of the low temperature pipe (1), and finally passes out at a 45° offset.

8. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 1, characterized in that, The inner layer temperature measuring fiber (5) is formed by inserting a circular stainless steel tube (7) to form an armored temperature measuring fiber.

9. The arrangement structure of a linear temperature-sensing optical fiber in a pipeline as described in claim 1, characterized in that, The inner layer temperature measuring fiber (5) is armored with an arc-shaped stainless steel cover (8).

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