Nonmetal composite pipeline based on optical fiber sensing and preparation and monitoring method thereof

Abstract

The nonmetal composite pipeline comprises a main pipe, a heat preservation layer, a cushioning layer and an outer protection layer are sequentially arranged on the outer surface of the main pipe outwards, an optical fiber groove is formed in the inner surface of the heat preservation layer in the axis direction of the main pipe, an optical fiber monitoring strip is arranged in the optical fiber groove, and the optical fiber monitoring strip is formed by connecting a plurality of optical fiber sensors in series through optical fibers. The optical fiber sensor is connected with the data acquisition and processing unit through an optical fiber, the data acquisition and processing unit is wirelessly connected with the communication module, and the communication module is wirelessly connected with the remote monitoring center. The invention further discloses a preparation and monitoring method of the nonmetal composite pipeline based on optical fiber sensing. Through a multi-layer composite structure, the problems of large weight, easy corrosion and the like are solved, the optical fiber monitoring strips are integrated to sense multiple strain and pressure parameters in real time, and high-precision pipeline health monitoring is achieved in combination with remote monitoring.

Description

Technical Field

[0001] The present invention belongs to the technical field of pipeline fluid transportation, and specifically relates to a non-metallic composite pipeline based on optical fiber sensing, and also relates to a preparation method and a monitoring method for the non-metallic composite pipeline based on optical fiber sensing. Background Art

[0002] At present, metal pipelines are mostly used in coal mines for long-distance slurry transportation, water transportation, oil transportation and other operations. When traditional metal pipelines leak liquid or get blocked during fluid transportation, it is necessary to manually check the positions of blockage points and leakage points, and it is impossible to realize on-line monitoring of the pipeline transportation status and quickly and accurately determine the pipeline fault location, resulting in low troubleshooting efficiency and greatly affecting the continuous transportation operation of on-site pipelines. Summary of the Invention

[0003] The first object of the present invention is to provide a non-metallic composite pipeline based on optical fiber sensing, which has the function of optical fiber sensing, can monitor the operation status of the pipeline in real time, realize accurate judgment and early warning of pipeline fault points, and improve the service life and inspection efficiency of the pipeline.

[0004] The second object of the present invention is to provide a preparation method for the non-metallic composite pipeline based on optical fiber sensing.

[0005] The third object of the present invention is to provide a monitoring method for the non-metallic composite pipeline based on optical fiber sensing.

[0006] The technical solution adopted by the present invention is a non-metallic composite pipeline based on optical fiber sensing, which includes a main pipe. A heat insulation layer, a shock absorption layer and an outer protection layer are sequentially arranged on the outer surface of the main pipe. A fiber optic groove is opened on the inner surface of the heat insulation layer along the axis direction of the main pipe, and a fiber optic monitoring strip is arranged in the fiber optic groove. The fiber optic monitoring strip is formed by connecting a number of fiber optic sensors in series through optical fibers. The fiber optic sensors are connected to a data acquisition and processing unit through optical fibers. The data acquisition and processing unit includes a light source, and the light source is sequentially connected to a modulator, a coupler and a photodetector through optical fibers. The photodetector is sequentially electrically connected to a signal processor and a memory. The fiber optic sensors are connected to the coupler through optical fibers. The memory is wirelessly connected to a communication module, and the communication module is wirelessly connected to a remote monitoring center.

[0007] The characteristics of the present invention also lie in that: the thickness of the heat insulation layer is 15-20 mm, the thickness of the shock absorption layer is twice the thickness of the heat insulation layer, and the thickness of the outer protection layer is the same as the thickness of the heat insulation layer.

[0008] The second technical solution adopted by the present invention is a preparation method for the non-metallic composite pipeline based on optical fiber sensing, which is specifically implemented according to the following steps: Step 1, extrude a modified polyoxymethylene resin polymer through an annular mold to form a main pipe; Step 2: Extrude and mold the molten mixture of mineral wool and glass fiber wool through an annular mold with fixed protruding grooves opened along the pipeline axis to form a thermal insulation layer with optical fiber grooves. Step 3: Connect several fiber optic sensors in series through optical fibers to form a fiber optic monitoring strip. The fiber optic monitoring strip is arranged in the optical fiber groove, and the fiber optic sensors are fiber-connected to the data acquisition and processing unit. Step 4: Extrude and mold the molten mixture of ethylene-vinyl acetate copolymer and thermoplastic polyurethane rubber (TPU) through a twin-screw extruder to form a shock-absorbing layer. Step 5: Attach the thermal insulation layer to the surface of the main pipe by thermal lamination. Wind the shock-absorbing layer around the thermal insulation layer with epoxy glue or epoxy resin, and spray molten polyethylene on the surfaces of the thermal insulation layer and the shock-absorbing layer in sequence to form an outer protective layer. Step 6: Place the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C - 150°C, and keep it warm for 2 - 4 hours to make a non-metallic composite pipeline based on fiber optic sensing.

[0009] The second technical solution of the present invention is further characterized in that: In Step 3, the data acquisition and processing unit includes a light source. The light source is sequentially connected to a modulator, a coupler, and a photodetector through an optical fiber. The photodetector is sequentially electrically connected to a signal processor and a memory. The fiber optic sensor is fiber-connected to the coupler. The memory is wirelessly connected to a communication module, and the communication module is wirelessly connected to a remote monitoring center.

[0010] In Step 1, the modified polyoxymethylene resin is formed by melt blending and compounding polyoxymethylene (POM) and TPU using a twin-screw extruder. The mass ratio of POM to TPU is 3:1. The modification method is using POM as the matrix and TPU with a hardness of 85A - 95A as the modification material. The melting temperature is 175°C - 215°C, the rotation speed of the screw machine is 200 - 500 rpm, the rotation time is 1 - 2 hours, the degree of polymerization requirement of POM is 1500 - 2500, and the degree of polymerization requirement of TPU is 100 - 200.

[0011] In Step 2, the molten mixture of mineral wool and glass fiber wool is formed by melt blending and compounding mineral wool and glass fiber wool using a twin-screw extruder. The mass ratio of mineral wool to glass fiber wool is 2:1. The temperature of the twin-screw extruder is 220°C - 260°C, the rotation speed of the screw machine is 200 - 500 rpm, and the rotation time is 30 - 50 min.

[0012] In Step 2, a connection line is formed between the optical fiber groove and the central axis of the main pipe. The relationship between the included angle α formed between adjacent two connection lines and the nominal diameter DN of the pipeline of the main pipe is as follows: when DN < 250, α = 60°; when 250 ≤ DN < 650, α = 45°; when 650 ≤ DN, α = 30°.

[0013] In Step 4, the shock-absorbing layer is formed by compounding ethylene-vinyl acetate copolymer and TPU in a molten blending manner using a twin-screw extruder. The mass ratio of ethylene-vinyl acetate copolymer to TPU is 3:1. The melting temperature is 180°C - 200°C, the rotational speed of the screw machine is 200 - 400 rpm, the rotation time is 1 - 2 hours. The degree of polymerization of ethylene-vinyl acetate copolymer is required to be 3500 - 5000, and the degree of polymerization of TPU is required to be 100 - 200. The shock-absorbing layer is helically wound around the outer wall of the insulation layer, and the winding angle is 40° - 45°.

[0014] The third technical solution adopted in the present invention is a monitoring method, and the steps are as follows: Step 1, use an optical fiber monitoring strip to monitor the tensile strain, compressive strain, bending strain and pressure parameters of the pipeline; Step 2, store and analyze the received monitoring data through a remote monitoring center, and evaluate the health status of the pipeline through the established pipeline status evaluation model.

[0015] In Step 2, when the tensile strain or compressive strain < 40 με, it is a normal working condition, and the remote monitoring center outputs "normal status" and regularly records the monitoring data; when 40 με ≤ tensile or compressive strain < 200 με, it is a micro-deformation, and the remote monitoring center gives a warning prompt of "local deformation"; when 200 με ≤ local tensile or compressive strain < 450 με, the remote monitoring center gives a warning prompt of "high-risk deformation", and at the same time triggers the blockage status evaluation model; when 200 με ≤ local compressive strain < 450 με and the pressure value ≤ 15%, the remote monitoring center gives an alarm prompt of "suspected leakage"; when the tensile or compressive strain ≥ 450 με, the pipeline is critically failed, and the remote monitoring center gives an alarm prompt of "emergency shutdown", and locates the blockage point position in combination with the strain parameter monitoring curve; when the pressure increase value ≥ 15%, the remote monitoring center gives an alarm prompt of "local high-risk blockage"; when the reduction value of the tensile or compressive strain along the flow direction ≤ 30% and the pressure increase value ≥ 20%, the remote monitoring center gives an alarm prompt of "long-distance blockage"; when the increase value of the bending strain ≥ 30% and the fluctuation range of the pressure parameter ≥ 5%, the remote monitoring center gives an alarm prompt of "leakage".

[0016] The beneficial effects of the present invention are: (1) The present invention relates to a non-metallic composite pipeline and a monitoring method based on optical fiber sensing. On the one hand, by using a non-metallic composite pipeline based on optical fiber sensing to replace the traditional metal pipeline, the problems of heavy weight and easy corrosion of the metal pipeline are solved. At the same time, the provided insulation layer can not only effectively prevent the pipeline from being affected by low temperature, but also play a role in protecting the optical fiber monitoring strip. The shock-absorbing layer can effectively relieve the severe vibration problem generated during the pipeline transportation operation, reduce the friction between the pipeline and the surrounding medium, and the high-strength outer protective layer can greatly improve the service life of the pipeline.

[0017] (2) The tensile strain, compressive strain, bending strain and pressure parameters of the pipeline are obtained in real time through the optical fiber monitoring strip, and the early damage and abnormal conditions of the pipeline can be detected in time, reducing the maintenance cost and downtime. At the same time, optical fiber sensing has the characteristics of high sensitivity and high precision, and can accurately measure the tiny changes of the pipeline, providing reliable data support for the pipeline condition assessment. The further set remote monitoring center realizes pipeline management and improves the safety and reliability of the pipeline. Description of the Drawings

[0018] Figure 1 It is a cross-sectional view of the overall structure of the non-metallic composite pipeline based on optical fiber sensing of the present invention; Figure 2 It is a cross-sectional view of the radial structure of the non-metallic composite pipeline based on optical fiber sensing of the present invention; Figure 3 It is a schematic diagram of the optical fiber groove of the thermal insulation layer of the present invention; Figure 4 It is a schematic diagram of the shock absorption layer of the present invention; Figure 5 It is a schematic diagram of the data acquisition and working unit system of the present invention; Figure 6 It is a schematic diagram of on-line monitoring of pipeline blockage faults in the embodiment of the present invention.

[0019] In the figure, 1. Outer protective layer, 2. Shock absorption layer, 3. Thermal insulation layer, 4. Optical fiber monitoring strip, 5. Main pipe, 6. Optical fiber sensor, 7. Data acquisition and processing unit, 8. Communication module, 9. Remote monitoring center, 10. Optical cable groove, 11. Blockage position, 12. Pressure abnormal point, 701. Light source, 702. Modulator, 703. Coupler, 704. Optical detector, 705. Signal processor, 706. Memory Detailed Description of the Invention The following is a detailed description in conjunction with the specific embodiments.

[0020] As Figure 1 shown, the non-metallic composite pipeline based on optical fiber sensing of the present invention includes a main pipe 5. The outer surface of the main pipe 5 is successively sleeved with a thermal insulation layer 3 and a shock absorption layer 2, and an outer protective layer 1 is successively arranged on the outer surfaces of the thermal insulation layer 3 and the shock absorption layer 2. An optical fiber groove 10 is opened on the inner surface of the thermal insulation layer 3 along the axis direction of the main pipe 5. An optical fiber monitoring strip 4 is arranged in the optical fiber groove 10. The optical fiber monitoring strip 4 is formed by connecting a plurality of optical fiber sensors 6 in series through optical fibers.

[0021] The main pipe 5 is processed from a modified polyoxymethylene resin material. The modification method is that POM is used as the matrix, and TPU with a hardness of 85A - 95A is selected as the modification material. The two can have good compatibility. By adding TPU to modify POM to form a molten mixture to make the inner pipe, it can not only ensure the strength of the main pipe itself with POM material, but also effectively improve the flexibility of the main pipe, improve its impact strength, and extend the service life of the main pipe.

[0022] The thermal insulation layer 3 is the first cladding layer of the main pipe 5, with both heat preservation and strength. On the one hand, it can give full play to the heat preservation effect of mineral wool, and on the other hand, it can give play to the high-strength characteristics of glass fiber wool. The thermal insulation layer 3 can not only provide heat preservation for the main pipe 5 to prevent the pipeline from being damaged by low temperature and affecting normal transportation operations, but also play a role in protecting the optical fiber monitoring strip 4. Among them, the mineral wool material can be made from slag wool raw materials.

[0023] The optical fiber monitoring strip 4 is closely attached to the main pipe 5 to ensure the accuracy of test data. Based on the size of the common nominal diameter DN of mine pipelines, a connection line is formed between the optical fiber groove 10 and the central axis of the main pipe 5. The relationship between the included angle α between adjacent two connection lines and the nominal diameter DN of the main pipe 5 is as follows: when DN < 250, α = 60°; when 250 ≤ DN < 650, α = 45°; when 650 ≤ DN, α = 30°. According to the different pipeline diameters, accurately setting the included angles of different types of optical fiber sensors can not only ensure the comprehensiveness of pipeline monitoring, but also avoid the inaccuracy of monitoring and waste of materials caused by the unified angle arrangement of optical fiber sensors in traditional pipelines. The optical fiber monitoring strip 4 monitors the tensile strain, compressive strain, bending strain and pressure parameters of the pipeline.

[0024] As Figure 2 shown, taking the nominal diameter DN of the pipeline = 75 as an example, according to the relationship between the included angle α of the above-mentioned optical fiber sensor 6 and the nominal diameter DN of the main pipe 5, the included angle at which the optical fiber sensor 6 is radially arranged along the surface of the main pipe 5 is 60°, that is, 6 optical fiber sensors 6 are evenly arranged along the surface of the main pipe 5.

[0025] As Figure 3 shown, a number of optical fiber grooves 10 are opened on the inner surface of the thermal insulation layer 3 along the axial direction of the pipeline. The inner surface of the optical fiber groove 10 has a certain viscosity, which is used to accommodate, protect and fix the optical fiber sensor 6, can play a role in protecting the optical fiber monitoring strip 4, and at the same time ensure the accuracy of monitoring data.

[0026] As Figure 4As shown in the figure, the shock-absorbing layer 2 is the third coating layer of the main pipe 5, which is formed by compounding ethylene-vinyl acetate copolymer and TPU through a twin-screw extruder in a melt blending manner. It can give full play to the flexibility of ethylene-vinyl acetate copolymer and enhance its wear resistance, so that the shock-absorbing layer 2 has a good compatibility effect and toughening modification effect, and reduces the vibration influence caused by the external influence on the pipeline. The shock-absorbing layer 2 is spirally wound around the outer surface of the insulation layer 3 in the form of a shock-absorbing belt, and the winding angle is 40° - 45°. The spiral winding structure can change the uneven stress on the shock-absorbing layer caused by traditional circumferential winding. The shock-absorbing belt reduces the risk of fracture of the shock-absorbing layer 2 by dispersing the longitudinal stress. At the same time, it can reduce the production cost of the pipeline, resist the vibration generated inside the pipeline during transportation operations from being transmitted to the pipeline surface, and resist the disturbance of the external environmental operations on the pipeline from affecting the inside of the pipeline, and can effectively ensure the stability and safety of the pipeline during operations. In addition, the shock-absorbing layer 2 arranged outside the insulation layer 3 can fully protect the insulation layer 3 from being structurally damaged by external influences and losing the insulation effect. At the same time, this structure can further improve the overall flexibility of the pipeline, making it easy to coil and transport and install in the underground environment.

[0027] The outer protective layer 1 is the third coating layer of the main pipe 5. The outer protective layer 1 is made of polyethylene material, which has high strength, increases the overall rigidity and compressive capacity of the pipeline, and has good corrosion resistance. It can effectively prevent the main pipe 5, the optical fiber monitoring strip 4, the insulation layer 3 and the shock-absorbing layer 2 from being damaged by external construction, and extend the service life of the pipeline.

[0028] Through the compounding of the above layers, the optical fiber monitoring strip 4 closely attached to the main pipe 5 can ensure the accuracy of monitoring data. At the same time, the insulation layer 3 covers the optical fiber monitoring strip 4, which can achieve a good insulation effect on the main pipe 5 and can play a good role in fixing and protecting the optical fiber monitoring strip 4. The shock-absorbing layer 2 is arranged between the outer protective layer 1 and the insulation layer 3, which can effectively resist the disturbance impact of the external vibration on the pipeline, and can also protect the insulation layer 3, the optical fiber monitoring strip 4 and the main pipe 5. The further arranged outer protective layer 1 can play a role in protecting the internal functional layers, and at the same time further improve the overall strength of the pipeline, with good corrosion resistance and flexibility, which is convenient for installation and transportation. At the same time, it can realize on-line monitoring of the pipeline operation state and achieve pipeline management.

[0029] Specifically, the thickness of the insulation layer 3 is 15 - 20 mm, the thickness of the shock-absorbing layer 2 is twice the thickness of the insulation layer 3, and the thickness of the outer protective layer 1 is the same as that of the insulation layer 3. Setting the thickness of the shock-absorbing layer 2 to be twice that of the insulation layer 3 can increase the elastic deformation space, extend the stress transmission path, avoid the action of external impact stress on the insulation layer, reduce the compression rate of the insulation layer by 30% - 50%, and improve the service life of the pipeline. At the same time, the outer protective layer 1 and the insulation layer 3 have the same thickness, which can effectively reduce the material cost by 10% - 15%, and at the same time avoid the too high rigidity of the pipeline caused by the too thick protective layer, making it more convenient for coiling and transporting the underground pipeline.

[0030] As Figure 5 shown, the data acquisition and processing unit 7 includes a light source 701. The light source 701 is sequentially connected to a modulator 702, a coupler 703, and a photodetector 704 through optical fibers. The photodetector 704 is sequentially electrically connected to a signal processor 705 and a memory 706. The fiber optic sensor 6 is connected to the coupler 703 through an optical fiber. The memory 706 is wirelessly connected to a communication module 8, and the communication module 8 is wirelessly connected to a remote monitoring center 9. The error control of the data analysis by the data acquisition and processing unit 7 is within 1‰. The wireless connection method is Ethernet, 4G / 5G, ZigBee.

[0031] The data acquisition and processing unit 7 collects and processes the signals of the fiber optic monitoring strip 4. The light source 701 generates a stable optical signal to provide a stable optical carrier. The modulator 702 modulates the emitted continuous light to endow the signal with a specific form of pulse. The coupler 703 manages the optical path to realize the routing and distribution of the optical signal, branches the modulated optical signal to the fiber optic monitoring strip 4, and directs the light carrying parameter information to the photodetector 704. The photodetector 704 completes the optoelectronic conversion, converting the optical signal into an electrical signal. The signal processor 705 amplifies, filters, demodulates, and digitally processes the electrical signal and extracts effective information. The memory 706 stores the original data and processing results to ensure data persistence and obtains the pipeline state characteristics.

[0032] The data processed by the memory 706 in the data acquisition and processing unit 7 is transmitted to the communication module 8.

[0033] The communication module 8 is used to transmit the monitoring data processed by the data acquisition and processing unit 7 to the remote monitoring center 9. The remote monitoring center 9 stores and analyzes the received monitoring data, and evaluates the health status of the pipeline through the established pipeline state evaluation model.

[0034] The remote monitoring center 9 includes a server, a database, and a user interface, and can store, analyze, and visually display the monitoring data, and timely detect the abnormal state of the pipeline and issue an alarm by setting thresholds and warning algorithms.

[0035] As Figure 6As shown in the figure, the schematic diagram of on-line monitoring of pipeline blockage points of the present invention, the specific monitoring principle is as follows: The surface pressure of the main pipe 5 is monitored in real time by the optical fiber monitoring strip 4. The data acquisition and processing unit 7 analyzes and processes the optoelectronic signals sent by the optical fiber sensor 6. After the signals are processed such as zero adjustment, amplification, and filtering, they are transmitted to the remote monitoring center 9 through the communication module 8. The remote monitoring center 9 converts the received optoelectronic signals into corresponding pressure values by using the pressure calculation model, and further draws the pressure curve on the surface of the main pipe 5 according to the pressure values. The abscissa of the pressure curve is the pipeline coordinate value (m) pre-imported into the database of the remote monitoring center 9, and the ordinate is the pipeline pressure (Pa). Based on the pressure curve, it can be judged whether there is a blockage at any position of the pipeline and the degree of blockage. Specifically, when the ordinate pressure coordinate value corresponding to a certain pipeline position on the abscissa of the pressure curve changes, it can be judged that this position is the blockage point of the pipeline. At the same time, the remote monitoring center 9 will judge the degree of blockage of the blockage point according to the magnitude of the pressure value fluctuation. When the degree of blockage exceeds the set threshold, the monitoring center will send an alarm signal and remind the staff to conduct a timely investigation. Similarly, the present invention can also monitor and give early warning of positions such as leakage points of the pipeline, realize pipeline management, and improve the safety and reliability of the pipeline.

[0036] The preparation method of the non-metallic composite pipeline based on optical fiber sensing is specifically implemented according to the following steps: Step 1, the modified polyoxymethylene resin polymer is extruded through an annular mold to form the main pipe 5. The main pipe 5 is processed from the modified polyoxymethylene resin material. The modification method is that POM is used as the matrix, and TPU with a hardness of 85A - 95A is selected as the modification material. Among them, POM and TPU are compounded by the melt blending method through a twin-screw extruder, and the mass ratio is set to 3:1. The melting temperature is 175°C - 215°C, the rotation speed of the screw machine is 200 - 500 rpm, the rotation time is 1 - 2 hours, the polymerization degree requirement of POM is 1500 - 2500, and the polymerization degree requirement of TPU is 100 - 200.

[0037] Step 2, the molten mixture of mineral wool and glass fiber wool is drawn and formed through an annular mold with a fixed groove opened along the pipeline axis direction to form the heat insulation layer 3 with the optical fiber groove 10. The heat insulation layer 3 is formed by the melt blending of the mineral wool material and the glass fiber wool material using a twin-screw extruder. The content ratio of the mineral wool to the glass fiber wool is set to 2:1. The temperature of the twin-screw extruder is 220°C - 260°C, the rotation speed of the screw machine is 200 - 500 rpm, and the rotation time is 30 - 50 min.

[0038] Step 3: Appropriately set a number of fiber optic sensors 6 in the fiber optic groove 10. The number of fiber optic sensors 6 forms a fiber optic monitoring strip 4. The fiber optic sensors 6 are connected to a data acquisition and processing unit 7 through optical fibers. The data acquisition and processing unit 7 includes a light source 701. The light source 701 is sequentially connected to a modulator 702, a coupler 703, and a photodetector 704 through optical fibers. The photodetector 704 is sequentially electrically connected to a signal processor 705 and a memory 706. The fiber optic sensors 6 are connected to the coupler 703 through optical fibers. The memory 706 is wirelessly connected to a communication module 8, and the communication module 8 is wirelessly connected to a remote monitoring center 9.

[0039] Based on the size of the common nominal diameter DN of the mining pipeline, a connection line is formed between the central axis of the fiber optic groove 10 and the main pipe 5. The relationship between the included angle α between adjacent two connection lines and the pipeline nominal diameter DN of the main pipe 5 is as follows: when DN < 250, α = 60°; when 250 ≤ DN < 650, α = 45°; when 650 ≤ DN, α = 30°.

[0040] Step 4: Melt and mix ethylene-vinyl acetate copolymer and TPU to form a shock-absorbing layer 2. The shock-absorbing layer 2 is formed by compounding ethylene-vinyl acetate copolymer and TPU through a twin-screw extruder in a melt blending manner, with a mass ratio of 3:1, a melting temperature of 180°C to 200°C, a screw machine rotation speed of 200 to 400 rpm, a rotation time of 1 to 2 hours, a required degree of polymerization of ethylene-vinyl acetate copolymer of 3500 to 5000, and a required degree of polymerization of TPU of 100 to 200.

[0041] Step 5: Attach the fiber optic monitoring strip 4 and the thermal insulation layer 3 to the surface of the main pipe 5 by thermal lamination. The shock-absorbing layer 2 is wound around the thermal insulation layer 3 with epoxy glue or epoxy resin, and molten polyethylene is sprayed on the surfaces of the shock-absorbing layer 2 and the thermal insulation layer 3 to form an outer protective layer 1.

[0042] Step 6: Place the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C to 150°C, and keep it warm for 2 to 4 hours to make a non-metallic composite pipeline based on fiber optic sensing.

[0043] Monitoring steps for using the non-metallic composite pipeline based on fiber optic sensing: Step 1: Use the fiber optic monitoring strip 4 to monitor the tensile strain, compressive strain, bending strain, and pressure parameters of the pipeline. Step 2: Store and analyze the received monitoring data through the remote monitoring center 9, and evaluate the health status of the pipeline through the established pipeline status evaluation model.

[0044] When the tensile strain or compressive strain < 40 με, it is in the normal working condition, and the remote monitoring center 9 outputs "Normal status" and regularly records the monitoring data; when 40 με ≤ tensile or compressive strain < 200 με, it is a micro-deformation, and the remote monitoring center 9 gives a warning prompt of "Local deformation"; when 200 με ≤ local tensile or compressive strain < 450 με, the remote monitoring center 9 gives a warning prompt of "High-risk deformation" and simultaneously triggers the blockage state assessment model; when 200 με ≤ local compressive strain < 450 με and the pressure value ≤ 15%, the remote monitoring center 9 gives an alarm prompt of "Suspected leakage"; when the tensile or compressive strain ≥ 450 με, the pipeline critically fails, and the remote monitoring center 9 gives an alarm prompt of "Emergency shutdown" and locates the blockage point position in combination with the strain parameter monitoring curve; when the pressure increase value ≥ 15%, the remote monitoring center 9 gives an alarm prompt of "Local high-risk blockage"; when the decrease value of the tensile or compressive strain along the flow direction ≤ 30% and the pressure increase value ≥ 20%, the remote monitoring center 9 gives an alarm prompt of "Long-distance blockage"; when the increase value of the bending strain ≥ 30% and the fluctuation range of the pressure parameter ≥ 5%, the remote monitoring center 9 gives an alarm prompt of "Leakage".

[0045] Embodiment 1 The non-metallic composite pipeline based on optical fiber sensing includes a main pipe 5. An insulating layer 3, a shock-absorbing layer 2, and an outer protective layer 1 are sequentially arranged outward on the outer surface of the main pipe 5. An optical fiber groove 10 is opened on the inner surface of the insulating layer 3 along the axis direction of the main pipe 5. An optical fiber monitoring strip 4 is arranged in the optical fiber groove 10. The optical fiber monitoring strip 4 is formed by connecting a plurality of optical fiber sensors 6 in series through optical fibers. The optical fiber sensors 6 are connected to a data acquisition and processing unit 7 through optical fibers. The data acquisition and processing unit 7 includes a light source 701. The light source 701 is sequentially connected to a modulator 702, a coupler 703, and a photodetector 704 through optical fibers. The photodetector 704 is sequentially electrically connected to a signal processor 705 and a memory 706. The optical fiber sensors 6 are connected to the coupler 703 through optical fibers. The memory 706 is wirelessly connected to a communication module 8. The communication module 8 is wirelessly connected to a remote monitoring center 9.

[0046] Embodiment 2 The non-metallic composite pipeline based on optical fiber sensing includes a main pipe 5. An insulating layer 3, a shock-absorbing layer 2, and an outer protective layer 1 are sequentially arranged outward on the outer surface of the main pipe 5. An optical fiber groove 10 is opened along the axial direction of the main pipe 5 on the inner surface of the insulating layer 3. An optical fiber monitoring strip 4 is arranged in the optical fiber groove 10. The optical fiber monitoring strip 4 is formed by connecting a plurality of optical fiber sensors 6 in series through optical fibers. The optical fiber sensors 6 are connected to a data acquisition and processing unit 7 through optical fibers. The data acquisition and processing unit 7 includes a light source 701. The light source 701 is sequentially connected to a modulator 702, a coupler 703, and a photodetector 704 through optical fibers. The photodetector 704 is sequentially electrically connected to a signal processor 705 and a memory 706. The optical fiber sensors 6 are connected to the coupler 703 through optical fibers. The memory 706 is wirelessly connected to a communication module 8. The communication module 8 is wirelessly connected to a remote monitoring center 9.

[0047] The thickness of the insulating layer 3 is 15 - 20 mm. The thickness of the shock-absorbing layer 2 is twice the thickness of the insulating layer 3. The thickness of the outer protective layer 1 is the same as that of the insulating layer 3.

[0048] Example 3 This example discloses a preparation method of a non-metallic composite pipeline based on optical fiber sensing, which is specifically implemented according to the following steps: Step 1, extrude the modified polyoxymethylene resin polymer through an annular mold to form the main pipe 5; Step 2, pull and extrude the molten mixture of mineral wool and glass fiber wool through an annular mold with a fixed protruding groove opened along the axial direction of the pipeline to form the insulating layer 3 with the optical fiber groove 10; Step 3, connect a plurality of optical fiber sensors 6 in series through optical fibers to form an optical fiber monitoring strip 4. The optical fiber monitoring strip 4 is arranged in the optical fiber groove 10. The optical fiber sensors 6 are optically connected to the data acquisition and processing unit 7; Step 4, pull and extrude the molten mixture of ethylene-vinyl acetate copolymer and TPU through a twin-screw extruder to form the shock-absorbing layer 2; Step 5, attach the insulating layer 3 to the surface of the main pipe 5 by thermal compounding. Wind the shock-absorbing layer 2 around the insulating layer 3 with epoxy glue or epoxy resin. Spray molten polyethylene on the surfaces of the insulating layer 3 and the shock-absorbing layer 2 in sequence to form the outer protective layer 1; Step 6, put the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C - 150°C, and keep it warm for 2 - 4 hours to make the non-metallic composite pipeline based on optical fiber sensing.

[0049] Example 4 This example discloses a preparation method of a non-metallic composite pipeline based on optical fiber sensing, which is specifically implemented according to the following steps: Step 1, extrude the modified polyoxymethylene resin polymer through an annular mold to form the main pipe 5; Step 2: The molten mixture of mineral wool and glass fiber wool is drawn and formed through an annular mold with fixed protruding grooves opened along the pipeline axis direction to form a thermal insulation layer 3 with an optical fiber groove 10. Step 3: A number of optical fiber sensors 6 are connected in series through optical fibers to form an optical fiber monitoring strip 4. The optical fiber monitoring strip 4 is arranged in the optical fiber groove 10, and the optical fiber sensors 6 are optically connected to a data acquisition and processing unit 7. Step 4: The molten mixture of ethylene-vinyl acetate copolymer and TPU is drawn and formed through a twin-screw extruder to form a shock-absorbing layer 2. Step 5: The thermal insulation layer 3 is attached to the surface of the main pipe 5 by means of thermal lamination. The shock-absorbing layer 2 is wound around the thermal insulation layer 3 with epoxy glue or epoxy resin. Molten polyethylene is sequentially sprayed on the surfaces of the thermal insulation layer 3 and the shock-absorbing layer 2 to form an outer protective layer 1. Step 6: The composite pipeline formed in Step 5 is placed in a curing furnace, heated to 120°C to 150°C, and kept warm for 2 to 4 hours to manufacture a non-metallic composite pipeline based on optical fiber sensing.

[0050] In Step 3, the data acquisition and processing unit 7 includes a light source 701. The light source 701 is optically connected to a modulator 702, a coupler 703, and a photodetector 704 in sequence. The photodetector 704 is electrically connected to a signal processor 705 and a memory 706 in sequence. The optical fiber sensor 6 is optically connected to the coupler 703. The memory 706 is wirelessly connected to a communication module 8, and the communication module 8 is wirelessly connected to a remote monitoring center 9.

[0051] Example 5 This example discloses a preparation method of a non-metallic composite pipeline based on optical fiber sensing, which is specifically implemented according to the following steps: Step 1: The modified polyoxymethylene resin polymer is extruded through an annular mold to form a main pipe 5. Step 2: The molten mixture of mineral wool and glass fiber wool is drawn and formed through an annular mold with fixed protruding grooves opened along the pipeline axis direction to form a thermal insulation layer 3 with an optical fiber groove 10. Step 3: A number of optical fiber sensors 6 are connected in series through optical fibers to form an optical fiber monitoring strip 4. The optical fiber monitoring strip 4 is arranged in the optical fiber groove 10, and the optical fiber sensors 6 are optically connected to a data acquisition and processing unit 7. Step 4: The molten mixture of ethylene-vinyl acetate copolymer and TPU is drawn and formed through a twin-screw extruder to form a shock-absorbing layer 2. Step 5: The thermal insulation layer 3 is attached to the surface of the main pipe 5 by means of thermal lamination. The shock-absorbing layer 2 is wound around the thermal insulation layer 3 with epoxy glue or epoxy resin. Molten polyethylene is sequentially sprayed on the surfaces of the thermal insulation layer 3 and the shock-absorbing layer 2 to form an outer protective layer 1. Step 6: Place the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C - 150°C, and keep it warm for 2 - 4 hours to produce a non-metallic composite pipeline based on fiber optic sensing.

[0052] In Step 1, the modified polyoxymethylene resin is formed by melt blending and compounding POM and TPU using a twin-screw extruder. The mass ratio of POM to TPU is 3:1. The modification method is using POM as the matrix and TPU with a hardness of 85A - 95A as the modification material. The melting temperature is 175°C - 215°C, the rotational speed of the screw machine is 200 - 500 rpm, the rotation time is 1 - 2 hours, the degree of polymerization requirement of POM is 1500 - 2500, and the degree of polymerization requirement of TPU is 100 - 200.

[0053] Example 6 This example discloses a preparation method of a non-metallic composite pipeline based on fiber optic sensing, which is specifically implemented according to the following steps: Step 1: Extrude the modified polyoxymethylene resin polymer through an annular die to form the main pipe 5; Step 2: Pull and extrude the molten mixture of mineral wool and glass fiber wool through an annular die with fixed protruding grooves opened along the pipeline axis direction to form a heat insulation layer 3 with fiber optic grooves 10; Step 3: Form a fiber optic monitoring strip 4 by connecting several fiber optic sensors 6 in series through optical fibers. The fiber optic monitoring strip 4 is arranged in the fiber optic grooves 10, and the fiber optic sensors 6 are optically connected to the data acquisition and processing unit 7; Step 4: Pull and extrude the molten mixture of ethylene-vinyl acetate copolymer and TPU through a twin-screw extruder to form a shock absorption layer 2; Step 5: Attach the heat insulation layer 3 to the surface of the main pipe 5 by thermal composite method. Wind the shock absorption layer 2 around the heat insulation layer 3 with epoxy glue or epoxy resin. Spray molten polyethylene on the surfaces of the heat insulation layer 3 and the shock absorption layer 2 in sequence to form an outer protective layer 1; Step 6: Place the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C - 150°C, and keep it warm for 2 - 4 hours to produce a non-metallic composite pipeline based on fiber optic sensing.

[0054] In Step 2, the molten mixture of mineral wool and glass fiber wool is formed by melt blending and compounding mineral wool and glass fiber wool using a twin-screw extruder. The mass ratio of mineral wool to glass fiber wool is 2:1. The temperature of the twin-screw extruder is 220°C - 260°C, the rotational speed of the screw machine is 200 - 500 rpm, and the rotation time is 30 - 50 min.

[0055] Example 7 This example discloses a preparation method of a non-metallic composite pipeline based on fiber optic sensing, which is specifically implemented according to the following steps: Step 1, extrude the modified polyoxymethylene resin polymer through an annular die to form the main pipe 5; Step 2, pull and extrude the molten mixture of mineral wool and glass fiber wool through an annular die with fixed protruding grooves opened along the pipe axis direction to form the heat insulation layer 3 with the optical fiber groove 10; Step 3, connect several optical fiber sensors 6 in series through optical fibers to form an optical fiber monitoring strip 4, the optical fiber monitoring strip 4 is arranged in the optical fiber groove 10, and the optical fiber sensors 6 are optically connected to the data acquisition and processing unit 7; Step 4, pull and extrude the molten mixture of ethylene-vinyl acetate copolymer and TPU through a twin-screw extruder to form the shock-absorbing layer 2; Step 5, attach the heat insulation layer 3 to the surface of the main pipe 5 by means of thermal compounding, wind the shock-absorbing layer 2 around the heat insulation layer 3 with epoxy glue or epoxy resin, and spray the molten polyethylene on the surfaces of the heat insulation layer 3 and the shock-absorbing layer 2 in sequence to form the outer protection layer 1; Step 6, put the composite pipe formed in Step 5 into a curing furnace, raise the temperature to 120°C - 150°C, and keep it warm for 2 - 4 hours to make the non-metallic composite pipe based on optical fiber sensing.

[0056] In Step 2, a connecting line is formed between the optical fiber groove 10 and the central axis of the main pipe 5, and the relationship between the included angle α formed between adjacent two connecting lines and the nominal diameter DN of the pipe of the main pipe 5 is as follows: when DN < 250, α = 60°, when 250 ≤ DN < 650, α = 45°, when 650 ≤ DN, α = 30°.

[0057] Example 8 This example discloses a preparation method of a non-metallic composite pipe based on optical fiber sensing, which is specifically implemented according to the following steps: Step 1, extrude the modified polyoxymethylene resin polymer through an annular die to form the main pipe 5; Step 2, pull and extrude the molten mixture of mineral wool and glass fiber wool through an annular die with fixed protruding grooves opened along the pipe axis direction to form the heat insulation layer 3 with the optical fiber groove 10; Step 3, connect several optical fiber sensors 6 in series through optical fibers to form an optical fiber monitoring strip 4, the optical fiber monitoring strip 4 is arranged in the optical fiber groove 10, and the optical fiber sensors 6 are optically connected to the data acquisition and processing unit 7; Step 4, pull and extrude the molten mixture of ethylene-vinyl acetate copolymer and TPU through a twin-screw extruder to form the shock-absorbing layer 2; Step 5, attach the heat insulation layer 3 to the surface of the main pipe 5 by means of thermal compounding, wind the shock-absorbing layer 2 around the heat insulation layer 3 with epoxy glue or epoxy resin, and spray the molten polyethylene on the surfaces of the heat insulation layer 3 and the shock-absorbing layer 2 in sequence to form the outer protection layer 1; Step 6: Place the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C - 150°C, and keep it warm for 2 - 4 hours to produce a non-metallic composite pipeline based on optical fiber sensing.

[0058] In Step 4, the shock-absorbing layer 2 is formed by compounding ethylene-vinyl acetate copolymer and TPU in a molten blending manner using a twin-screw extruder. The mass ratio of ethylene-vinyl acetate copolymer to TPU is 3:1. The melting temperature is 180°C - 200°C, the rotation speed of the screw machine is 200 - 400 rpm, the rotation time is 1 - 2 hours. The degree of polymerization of ethylene-vinyl acetate copolymer is required to be 3500 - 5000, and the degree of polymerization of TPU is required to be 100 - 200. The shock-absorbing layer 2 is helically wound around the outer wall of the heat-insulating layer 3 at a winding angle of 40° - 45°.

[0059] Example 9 This example provides a monitoring method for a non-metallic composite pipeline based on optical fiber sensing, which specifically includes the following steps: Step 1: Use the optical fiber monitoring strip 4 to monitor the tensile strain, compressive strain, bending strain, and pressure parameters of the pipeline. Step 2: Store and analyze the received monitoring data through the remote monitoring center 9, and evaluate the health status of the pipeline through the established pipeline status evaluation model.

[0060] Example 10 This example provides a monitoring method for a non-metallic composite pipeline based on optical fiber sensing, which specifically includes the following steps: Step 1: Use the optical fiber monitoring strip 4 to monitor the tensile strain, compressive strain, bending strain, and pressure parameters of the pipeline. Step 2: Store and analyze the received monitoring data through the remote monitoring center 9, and evaluate the health status of the pipeline through the established pipeline status evaluation model.

[0061] In step 2, when the tensile strain or compressive strain is less than 40με, it is a normal working condition, and the remote monitoring center 9 outputs "normal status" and records the monitoring data regularly; when 40με≤tensile or compressive strain<200με, it is a micro deformation, and the remote monitoring center 9 warns of "local deformation"; when 200με≤local tensile or compressive strain<450με, the remote monitoring center 9 warns of "high-risk deformation" and triggers the blockage status assessment model; when 200με≤local compressive strain<450με, and the pressure value is ≤15%, the remote monitoring center 9 alarms Prompt "suspected leakage"; when the tensile or compressive strain is ≥450με, the pipeline fails critically, the remote monitoring center 9 alarms "emergency shutdown", and locates the blockage point in combination with the strain parameter monitoring curve; when the pressure increase value is ≥15%, the remote monitoring center 9 alarms "local high-risk blockage"; when the tensile or compressive strain decreases along the flow direction by ≤30%, the pressure increase value is ≥20%, the remote monitoring center 9 alarms "long-distance blockage"; when the bending strain increase value is ≥30%, and the pressure parameter fluctuation amplitude is ≥5%, the remote monitoring center 9 alarms "leakage".

Claims

1. A non-metallic composite pipeline based on fiber optic sensing, characterized in that It includes a main pipe (5), and a heat insulation layer (3), a shock absorption layer (2), and an outer protective layer (1) are sequentially arranged outward on the outer surface of the main pipe (5). An optical fiber groove (10) is formed in the inner surface of the heat insulation layer (3) along the axial direction of the main pipe (5). An optical fiber monitoring strip (4) is arranged in the optical fiber groove (10). The optical fiber monitoring strip (4) is formed by connecting a plurality of optical fiber sensors (6) in series through optical fibers. The optical fiber sensors (6) are connected to a data acquisition and processing unit (7) through optical fibers. The data acquisition and processing unit (7) includes a light source (701). The light source (701) is sequentially connected to a modulator (702), a coupler (703), and a photodetector (704) through optical fibers. The photodetector (704) is sequentially electrically connected to a signal processor (705) and a memory (706). The optical fiber sensors (6) are connected to the coupler (703) through optical fibers. The memory (706) is wirelessly connected to a communication module (8). The communication module (8) is wirelessly connected to a remote monitoring center (9).

2. The non-metallic composite pipeline based on optical fiber sensing according to claim 1, characterized in that, The thickness of the heat insulation layer (3) is 15 - 20 mm. The thickness of the shock absorption layer (2) is twice the thickness of the heat insulation layer (3). The thickness of the outer protective layer (1) is the same as the thickness of the heat insulation layer (3).

3. Preparation method of non-metallic composite pipeline based on optical fiber sensing, characterized in that, Specifically, it is implemented according to the following steps: Step 1, extrude a modified polyoxymethylene resin polymer through an annular die to form the main pipe (5); Step 2, pull and extrude a molten mixture of mineral wool and glass fiber wool through an annular die with fixed protruding grooves formed along the axial direction of the pipeline to form the heat insulation layer (3) with the optical fiber groove (10); Step 3, connect a plurality of optical fiber sensors (6) in series through optical fibers to form an optical fiber monitoring strip (4). The optical fiber monitoring strip (4) is arranged in the optical fiber groove (10). The optical fiber sensors (6) are connected to the data acquisition and processing unit (7) through optical fibers; Step 4, pull and extrude a molten mixture of ethylene - vinyl acetate copolymer and TPU through a twin - screw extruder to form the shock absorption layer (2); Step 5, attach the heat insulation layer (3) to the surface of the main pipe (5) by thermal lamination. The shock absorption layer (2) is wound around the heat insulation layer (3) with epoxy glue or epoxy resin. Spray molten polyethylene on the surfaces of the heat insulation layer (3) and the shock absorption layer (2) in sequence to form the outer protective layer (1); Step 6, put the composite pipeline formed in Step 5 into a curing furnace, heat it up to 120°C - 150°C, and keep it warm for 2 - 4 hours to make a non - metallic composite pipeline based on optical fiber sensing.

4. The preparation method of the non-metallic composite pipeline based on optical fiber sensing according to claim 3, characterized in that, In Step 3, the data acquisition and processing unit (7) includes a light source (701). The light source (701) is sequentially connected to a modulator (702), a coupler (703), and a photodetector (704) through optical fibers. The photodetector (704) is sequentially electrically connected to a signal processor (705) and a memory (706). The optical fiber sensors (6) are connected to the coupler (703) through optical fibers. The memory (706) is wirelessly connected to a communication module (8). The communication module (8) is wirelessly connected to a remote monitoring center (9).

5. The preparation method of the non-metallic composite pipeline based on optical fiber sensing according to claim 3, characterized in that, In step 1, the modified polyoxymethylene resin is formed by melt blending and compounding POM and TPU using a twin-screw extruder. The mass ratio of POM to TPU is 3:

1. The modification method uses POM as the matrix and TPU with a hardness of 85A - 95A as the modification material. The melting temperature is 175°C - 215°C, the screw machine speed is 200 - 500 rpm, the rotation time is 1 - 2 hours, the required degree of polymerization of POM is 1500 - 2500, and the required degree of polymerization of TPU is 100 - 200.

6. The preparation method of the non-metallic composite pipeline based on optical fiber sensing according to claim 3, characterized in that, In step 2, the molten mixture of mineral wool and glass fiber wool is formed by melt blending and compounding mineral wool and glass fiber wool using a twin-screw extruder. The mass ratio of mineral wool to glass fiber wool is 2:

1. The temperature of the twin-screw extruder is 220°C - 260°C, the screw machine speed is 200 - 500 rpm, and the rotation time is 30 - 50 min.

7. The manufacturing method of the non-metallic composite pipeline based on optical fiber sensing according to claim 3, characterized in that, In step 2, a line is formed between the optical fiber groove (10) and the central axis of the main pipe (5). The relationship between the included angle α formed between adjacent two lines and the nominal diameter DN of the pipe of the main pipe (5) is as follows: when DN < 250, α = 60°; when 250 ≤ DN < 650, α = 45°; when 650 ≤ DN, α = 30°.

8. The preparation method of the non-metallic composite pipeline based on optical fiber sensing according to claim 3, characterized in that, In step 4, the shock-absorbing layer (2) is formed by compounding ethylene-vinyl acetate copolymer and TPU using a twin-screw extruder in a melt blending manner. The mass ratio of ethylene-vinyl acetate copolymer to TPU is 3:

1. The melting temperature is 180°C - 200°C, the screw machine speed is 200 - 400 rpm, the rotation time is 1 - 2 hours, the required degree of polymerization of ethylene-vinyl acetate copolymer is 3500 - 5000, and the required degree of polymerization of TPU is 100 - 200. The shock-absorbing layer (2) is helically wound around the outer wall of the thermal insulation layer (3), and the winding angle is 40° - 45°.

9. Monitoring method for non-metallic composite pipelines based on optical fiber sensing, characterized in that The non-metallic composite pipe based on optical fiber sensing as claimed in claim 1 specifically comprises the following steps: Step 1, using the optical fiber monitoring strip (4) to monitor the tensile strain, compressive strain, bending strain and pressure parameters of the pipe. Step 2, storing and analyzing the received monitoring data through the remote monitoring center (9), and evaluating the health status of the pipe through the established pipe status evaluation model.

10. The monitoring method of the non-metallic composite pipeline based on optical fiber sensing according to claim 9, characterized in that, In step 2, when the tensile strain or the compressive strain is less than 40 με, it is a normal working condition, and the remote monitoring center (9) outputs "normal state" and regularly records monitoring data; when 40 με≤tensile or compressive strain<200 με, it is a micro deformation, and the remote monitoring center (9) warns of "local deformation"; when 200 με≤local tensile or compressive strain<450 με, the remote monitoring center (9) warns of "high risk deformation" and triggers a blockage state assessment model; when 200 με≤local compressive strain<450 με and the pressure value is less than 15%, the remote monitoring center (9) warns of "high risk deformation" and triggers a blockage state assessment model; The remote monitoring center (9) will give an alarm prompting "suspected leakage"; when the tensile or compressive strain is ≥450με, the pipeline is critically failed, and the remote monitoring center (9) will give an alarm prompting "emergency shutdown" and locate the blockage point in combination with the strain parameter monitoring curve; when the pressure increase value is ≥15%, the remote monitoring center (9) will give an alarm prompting "local high-risk blockage"; when the tensile or compressive strain decreases along the flow direction by ≤30%, and the pressure increase value is ≥20%, the remote monitoring center (9) will give an alarm prompting "long-distance blockage"; when the bending strain increase value is ≥30%, and the pressure parameter fluctuation amplitude is ≥5%, the remote monitoring center (9) will give an alarm prompting "leakage".

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