Distributed self-heating temperature sensing optical cable and marine pipeline leakage monitoring method

Abstract

The invention discloses a distributed self-heating temperature sensing optical cable and a marine pipeline leakage monitoring method, and belongs to the technical field of optical cable structures and pipeline leakage monitoring, the distributed self-heating temperature sensing optical cable comprises a fiber core, the outer side of the fiber core is coated with a cladding layer, the outer side of the cladding layer is coated with a coating layer, a heating structure is attached to the outer side of the coating layer, and the heating structure is attached to the outer side of the coating layer. An insulating material layer is arranged on the outer side of the heating structure, a steel wire reinforcing piece is attached to the outer side of the insulating material layer in a surrounding mode, and the outer side of the steel wire reinforcing piece is wrapped with a sheath. According to the distributed self-heating temperature sensing optical cable and the marine pipeline leakage monitoring method, the optical cable has a heating structure and a high external force resistance structure, the monitoring method can dynamically monitor whether the pipeline leaks or not in real time, and the distributed self-heating temperature sensing optical cable and the marine pipeline leakage monitoring method have higher resolution, higher response speed and long-distance monitoring.

Description

Technical Field

[0001] The present invention relates to the technical field of optical cable structure and pipeline leakage monitoring, and in particular to a distributed self-heating temperature sensing optical cable and a marine pipeline leakage monitoring method. Background Art

[0002] Fiber optic sensing technology has gradually played an important role in various fields in recent years, among which fiber optic temperature sensing is an important part. Most traditional temperature sensors have the problems of only being able to measure the temperature of a single point, being large in size, and being difficult to integrate with the object being measured. Compared with traditional temperature sensors, fiber optic sensors have the following advantages: light weight, strong anti-interference ability, continuous measurement, high resolution, high sensitivity, low loss, long-distance detection, etc.

[0003] Pipeline leakage monitoring belongs to the category of pipeline health monitoring, and it is crucial to realize real-time monitoring of pipeline leakage. For example, when the submarine pipeline transports fluids such as oil, real-time monitoring of the pipeline through sensors can reduce economic losses and environmental pollution caused by untimely discovery of fluid leakage. Considering the volume and cost problems of traditional sensors, small-volume and low-cost optical fibers can solve the problems faced by pipeline leakage monitoring.

[0004] At present, when the ambient temperature inside and outside the pipeline is the same, the pipeline detection method based on temperature sensing optical fiber cannot judge the occurrence of pipeline leakage based on the change in fiber temperature because the fiber temperature does not change significantly after the leaked fluid flushes the fiber. Summary of the invention

[0005] The purpose of the present invention is to provide a distributed self-heating temperature sensing optical cable and a method for monitoring leakage of an ocean pipeline. The optical cable has a heating structure and a high external force resistance structure. The monitoring method can dynamically monitor whether a pipeline leaks in real time and has higher resolution, response speed and long-distance monitoring.

[0006] To achieve the above-mentioned purpose, the present invention provides a distributed self-heating temperature sensing optical cable, including a fiber core, the outer side of the fiber core is covered with a cladding, the outer side of the cladding is covered with a coating layer, the outer side of the coating layer is attached to a heating structure, the outer side of the heating structure is provided with an insulating material layer, the outer side of the insulating material layer is surrounded and attached with a steel wire reinforcement, and the outer side of the steel wire reinforcement is covered with a sheath.

[0007] Preferably, the heating structure is a U-shaped structure with a hollow middle and a connected bottom, and the fiber core is located at the center of the inner side of the heating structure; the positive terminal and the negative terminal of the heating structure are located on the same side.

[0008] The present invention also provides a method for monitoring leakage of a marine pipeline using a distributed self-heating temperature sensing optical cable, comprising the following steps:

[0009] S1. Laying pipelines and optical cables;

[0010] S2. Connect the fiber core of the optical cable to the demodulation system through an optical fiber jumper, and the demodulation system is connected to the host computer through a network cable;

[0011] S3, connecting the heating structure inside the optical cable to a power source for heating, so that the temperature of the optical cable and the pipeline is higher than the temperature of the fluid inside and outside the pipeline and remains stable;

[0012] S4. The host computer receives the data from the demodulation system in real time. If it is found that the temperature of the optical cable at a certain location decreases, it means that a leak occurs at the corresponding pipeline location.

[0013] Preferably, in S1, the structure of the pipeline is designed to be three-layered, namely, an inner lining layer, a compensating reinforcement layer and an outer covering layer from the inside to the outside. The optical cable is tightly spirally wound on the outer surface of the compensating reinforcement layer of the pipeline, and the optical cable is coated on the pipeline by the outer covering layer of the pipeline.

[0014] Preferably, a groove is formed on the outer surface of the compensating reinforcement layer of the pipe, and the optical cable is placed in the groove.

[0015] Preferably, the positive terminal and the negative terminal of the heating structure of the optical cable are connected to the positive electrode and the negative electrode of the power supply through the positive power line and the negative power line respectively.

[0016] Therefore, the beneficial effects of the present invention using the above-mentioned distributed self-heating temperature sensing optical cable and marine pipeline leakage monitoring method are as follows:

[0017] (1) Real-time monitoring over long distances: Optical fiber has low loss and anti-interference characteristics, and can monitor pipelines of hundreds of meters. The demodulation system demodulates the signal in real time and uploads the temperature values ​​of each part of the optical cable with high resolution.

[0018] (2) Simple structure and low cost: The array can be formed by only a single optical cable, avoiding the use of hundreds or thousands of traditional temperature sensor unit arrays for single-point temperature measurement, optimizing the monitoring system while reducing costs. The sensor is light in weight and small in size, making it easier to integrate the pipeline and optical cable, and is not based on the temperature difference between the fluid inside and outside the pipeline.

[0019] (3) High structural strength: The optical cable has a Kevlar structure and an electrified steel mesh protection, which can effectively prevent external damage. At the same time, the pipeline can be designed in layers, and the optical cable can be laid in the pipeline. The inner and outer layers of the pipeline can effectively prevent the pressure and impact of the fluid on the optical cable.

[0020] (4) Rapid heating of the optical fiber: The optical fiber is close to the heating structure, avoiding the problems of slow heating and long temperature stabilization time caused by indirect heat transfer.

[0021] (5) Low electrical power required: The optical cable uses metal heating, and the conversion of electrical energy into thermal energy is highly efficient. At the same time, the presence of the inner lining and outer covering makes the optical cable have good thermal insulation effect and does not rely on high-power power supply.

[0022] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic diagram of the structure of the optical cable;

[0024] Figure 2 is a schematic diagram of the heating structure of the optical cable;

[0025] Figure 3 It is a schematic diagram of the connection structure of a system using optical cables for pipeline leakage monitoring.

[0026] Reference numerals

[0027] 1. Power supply; 2. Positive power cord; 3. Negative power cord; 4. Optical cable; 41. Fiber core; 42. Cladding; 43. Coating layer; 44. Insulation material layer; 45. Heating structure; 46. Steel wire reinforcement; 47. Sheath; 5. Pipeline; 6. Demodulation system; 7. Fiber jumper; 8. Host computer; 9. Network cable. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0030] Embodiment 1

[0031] like Figure 1As shown, the present invention provides a distributed self-heating temperature sensing optical cable, the optical cable 4 specifically includes a core 41, the outer side of the core 41 is coated with a cladding 42, the outer side of the cladding 42 is coated with a coating layer 43, and the outer side of the coating layer 43 is attached with a heating structure 45. In this embodiment, the heating structure 45 is processed on both sides of the Kai tube so that its side surfaces become two integral parts, and the tail is connected to make the heating structure 45 a U-shaped structure with a hollow middle and a connected bottom. The core 41 is located at the center of the inner side of the heating structure 45. The heating structure 45 is close to the core 41, which is conducive to the rapid heating of the core 41 and can also provide protection for the core 41 to a certain extent. Since the circuit loop is realized at the tail, the positive terminal and the negative terminal of the heating structure 45 are located on the same side, and the connector of the core 41 can also be located on the same side as the terminal of the heating structure 45 according to the situation.

[0032] An insulating material layer 44 is provided on the outside of the heating structure 45, and a steel wire reinforcement member 46 is attached around the outside of the insulating material layer 44, which can effectively improve the strength of the optical cable 4. The insulating material layer 44 is arranged between the heating structure 45 and the steel wire reinforcement member 46, which can prevent the current in the heating structure 45 from leaking into the steel wire reinforcement member 46, thereby avoiding heating failure and internal short circuit of the optical cable. The outer side of the steel wire reinforcement member 46 is covered with a sheath 47.

[0033] This embodiment also provides a method for monitoring leakage of a marine pipeline using a distributed self-heating temperature sensing optical cable, comprising the following steps:

[0034] S1. Laying pipelines 5 and optical cables 4, specifically:

[0035] The structure of the pipe 5 is designed to be three-layered, including an inner lining layer, a compensating reinforcement layer and an outer covering layer from the inside to the outside. The optical cable 4 is tightly wound on the outer surface of the compensating reinforcement layer of the pipe 5 with a certain pitch and a certain prestressed spiral, which not only plays a role in heat preservation, but also plays a role in protecting the optical cable 4. The optical cable 4 is wrapped on the pipe 5 through the outer covering layer of the pipe 5, so that the optical cable 4 can be protected and insulated by the inner lining layer and the outer covering layer.

[0036] When the processing environment of the pipeline 5 is relatively bad, such as high temperature, large external force, etc., which may easily cause the optical cable 4 to break, a groove can be made on the surface of the compensation reinforcement layer, and the optical cable 4 can be placed in the groove to provide good protection for the optical cable 4. If there is no such problem, the optical cable 4 can be directly spirally wound on the surface of the compensation reinforcement layer, and then wrapped with an outer covering layer to complete the laying.

[0037] S2, connecting the fiber core 41 of the optical cable 4 to the demodulation system 6 via the optical fiber jumper 7, and connecting the demodulation system 6 to the host computer 8 via the network cable 9.

[0038] S3, connecting the heating structure 45 inside the optical cable 4 to the power source 1 for heating, specifically: connecting the positive terminal and the negative terminal of the heating structure 45 of the optical cable 4 to the positive and negative electrodes of the power source 1 through the positive power line 2 and the negative power line 3, respectively. After power is turned on, the temperature of the optical cable 4 and the pipeline 5 is higher than the temperature of the fluid inside and outside the pipeline and remains stable.

[0039] S4. The host computer 8 receives the data of the demodulation system 6 in real time. If it is found that the temperature of the optical cable 4 at a certain position decreases, it indicates that a leak occurs at the corresponding position of the pipeline 5.

[0040] During actual use, the positive electrode and negative electrode of the power supply 1 are connected to the heating structure 45 in the optical cable 4 wound on the compensation reinforcement layer of the pipeline 5 through the positive power line 2 and the negative power line 3 respectively, and the fiber core 41 in the optical cable 4 is connected to the demodulation system 6 through the optical fiber jumper 7, and the demodulation system 6 is connected to the host computer 8 through the network cable 9.

[0041] The heating structure 45 of the optical cable 4 is energized to heat the fiber core 41. After the temperature of the fiber core 41 stabilizes, a temperature difference is formed between the fiber core 41 and the fluid inside and outside the pipe 5. This can solve the problem that when the temperature difference between the fluid inside and outside the pipe 5 is small, the leaked fluid flushes the optical fiber, making the optical fiber temperature change not obvious, resulting in missed reports.

[0042] The fluid flushing outside the pipeline 5 and the fluid transported inside the pipeline 5 wear the inner lining layer and the outer covering layer respectively. If any layer is completely worn by the fluid, it will threaten the transportation health of the pipeline 5, and there is a risk of fluid leakage inside the pipeline 5. When a pipeline leakage event occurs, the fluid flushes the optical cable 4, making the temperature of the optical cable 4 at the location where the leaking fluid is flushed lower than the temperature at other locations; conversely, when the temperature at a certain location of the optical cable 4 is lower than the temperature at other locations, it indicates that a leak has occurred at the location of the pipeline 5 corresponding to the optical cable 4. The demodulation system 6 demodulates the overall temperature data of the fiber core 41 in real time, and transmits the data to the host computer 8 through the network cable 9, visualizes the temperature of the optical cable 4 as the cable length-temperature curve value and stores it in real time, and observes the changes in the temperature curve to timely discover the occurrence of pipeline leakage events. Finally, a mapping relationship is established between pipeline leakage events and changes in optical cable temperature.

[0043] The positive and negative electrodes of the self-heating temperature sensing optical cable of the present invention and the optical fiber jumper connector are on the same side, so that the electric wire and the optical fiber connector can be integrated. The monitoring method can not only realize the leakage monitoring of the pipeline, but also realize the integration of the pipeline and the optical fiber.

[0044] Therefore, the present invention adopts the above-mentioned distributed self-heating temperature sensing optical cable and marine pipeline leakage monitoring method. The optical cable has a heating structure and a high external force resistance structure. The monitoring method can dynamically monitor whether the pipeline is leaking in real time, and has higher resolution, response speed and long-distance monitoring.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A distributed self-heating temperature sensing optical cable, characterized in that: It includes a fiber core, the outer side of the fiber core is covered with a cladding, the outer side of the cladding is covered with a coating layer, the outer side of the coating layer is attached to a heating structure, the outer side of the heating structure is provided with an insulating material layer, the outer side of the insulating material layer is surrounded and attached with a steel wire reinforcement, and the outer side of the steel wire reinforcement is covered with a sheath.

2. A distributed self-heating temperature sensing optical cable according to claim 1, characterized in that: The heating structure is a U-shaped structure with a hollow middle and a connected bottom. The fiber core is located at the center of the inner side of the heating structure. The positive terminal and the negative terminal of the heating structure are located on the same side.

3. A method for monitoring leakage of marine pipelines using distributed self-heating temperature sensing optical cables, characterized in that: The following steps are involved: S1. Laying pipelines and optical cables; S2. Connect the fiber core of the optical cable to the demodulation system through an optical fiber jumper, and the demodulation system is connected to the host computer through a network cable; S3, connecting the heating structure inside the optical cable to a power source for heating, so that the temperature of the optical cable and the pipeline is higher than the temperature of the fluid inside and outside the pipeline and remains stable; S4. The host computer receives the data from the demodulation system in real time. If it is found that the temperature of the optical cable at a certain location decreases, it means that a leak occurs at the corresponding pipeline location.

4. The method for monitoring leakage of a marine pipeline using a distributed self-heating temperature sensing optical cable according to claim 3 is characterized in that: In S1, the structure of the pipeline is designed to be three-layered, including an inner lining layer, a compensating reinforcement layer and an outer covering layer from the inside to the outside. The optical cable is tightly wound spirally on the outer surface of the compensating reinforcement layer of the pipeline, and the optical cable is covered on the pipeline by the outer covering layer of the pipeline.

5. The method for monitoring leakage of a marine pipeline using a distributed self-heating temperature sensing optical cable according to claim 4, characterized in that: Grooves are made on the outer surface of the compensating reinforcement layer of the pipe, and the optical cables are placed in the grooves.

6. The method for monitoring leakage of a marine pipeline using a distributed self-heating temperature sensing optical cable according to claim 4, characterized in that: The positive terminal and the negative terminal of the heating structure of the optical cable are connected to the positive electrode and the negative electrode of the power supply through the positive power line and the negative power line respectively.

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