A smart pipeline for fluid monitoring

Abstract

The present invention is an intelligent pipeline for fluid monitoring, comprising: a pipeline, a data acquisition module, a data processing module, a wireless transmitting module, a wireless receiving module, a display screen and a power supply module. The power supply module, the data acquisition module and the wireless transmitting module are connected in sequence, the data acquisition module is vertically fixed to the inner wall of the pipeline, and the power supply module and the wireless transmitting module are sealed and fixed to the inner upper wall of the pipeline; the wireless receiving module, the data processing module and the display screen are connected in sequence and fixed to the outer side of the pipeline. The data acquisition module bends and deforms with the movement of the fluid, and then generates an electrical signal related thereto, thereby realizing the monitoring of the fluid state in the pipeline. The present invention can effectively detect and monitor fluid state signals that are difficult to collect in conventional pipeline systems, and is suitable for pipeline system requirements under many complex conditions.

Description

Technical Field

[0001] The invention belongs to the field of intelligent pipelines, and in particular relates to an intelligent pipeline for fluid monitoring. Background Art

[0002] In industrial production life, pipeline systems are widely used in various industries and fields due to their own characteristics, such as the transportation of solid particles, powders, slurries, fluids, gases, etc. In actual industrial production, pipeline systems play an extremely important role in important and specific scenarios such as petrochemical transportation, sewage treatment, and natural gas transportation. It can be said that pipelines are the lifeline of these industries. However, due to the huge characteristics and complexity of the pipeline system, the status monitoring of fluids or gases in the pipeline has become a difficult problem. Every year, there are countless accidents of all sizes caused by inadequate monitoring. For example, in the oil and gas field, the consequences are not only economic losses, but also huge pollution to the environment.

[0003] Traditional pipeline monitoring mainly relies on manual inspections and periodic inspections of the state of the material in the pipe to determine the state of the fluid. These methods are not only time-consuming and labor-intensive, but also lack a certain degree of timeliness, making it difficult to quickly and efficiently find relevant problems and conduct real-time monitoring. With the development of technology, some new technologies have also emerged, such as analysis of the quality and volume of fluid in the pipeline, electromagnetic analysis, pipeline pressure analysis, etc. Among them, methods such as quality and volume analysis often require monitoring only after the state of the fluid in the pipe has changed or some faults have occurred. The main problem with the latter two methods is that they lack certain advantages in real-time monitoring. At the same time, the small monitoring range and the need for regular maintenance of equipment are also some of the shortcomings of these technologies. Summary of the invention

[0004] The purpose of the present invention is to provide an intelligent pipeline for fluid monitoring based on new sensor perception in response to the traditional and older pipeline fluid monitoring method, which has the function of real-time monitoring of the speed, direction and flow state of the pipeline fluid.

[0005] In order to achieve the above functions, this monitoring system is implemented through the following series of technical solutions: an intelligent pipeline for fluid monitoring, including: a pipeline, a data acquisition module, a data processing module, a wireless transmitting module, a wireless receiving module, a display screen and a power supply module. The power supply module, the data acquisition module and the wireless transmitting module are connected in sequence, the data acquisition module is vertically fixed to the inner wall of the pipeline, and the power supply module and the wireless transmitting module are sealed and fixed to the inner upper wall of the pipeline; the wireless receiving module, the data processing module and the display screen are connected in sequence and fixed to the outside of the pipeline. The data acquisition module collects the electromechanical signal of the fluid in the pipeline, which is transmitted by the wireless transmitting module, and the electromechanical signal is received by the wireless receiving module. The electromechanical signal is then converted into flow rate data through signal processing by the data processing module, and finally displayed on the display screen.

[0006] The data acquisition module is a piezoelectric / piezoresistive dual-mode flexible sensor, which includes a piezoelectric layer and a piezoresistive layer; the piezoelectric layer is composed of a piezoelectric composite film with a microstructure and a gold electrode sprayed on the composite film; the piezoresistive layer is composed of a graphene film sprayed on the surface of the gold electrode with a microstructure and a PDMS with a microstructure; the microarray structure is a regular tetrahedral microarray, and the ratio k of the side length of the upper bottom surface of the array to the side length of the lower bottom surface and the array height h satisfy:

[0007]

[0008] in, is the first variable, specifically

[0009] is the second variable, specifically is the third variable, specifically c ij 、e ij and k ij are the elastic stiffness constant, piezoelectric stress constant and dielectric constant respectively; a2 is the side length of the bottom surface of the regular tetrahedron; F represents pressure, t is time, R is the internal resistance of the voltmeter, and V is the output voltage of the piezoelectric layer.

[0010] Furthermore, the regular tetrahedral microarray is preferably a pyramidal microarray.

[0011] Furthermore, the height of the regular tetrahedral microarray is preferably h=40 μm.

[0012] Furthermore, the regular tetrahedral microarray of the piezoelectric layer is prepared by the following method:

[0013] (1) 1 g of BTO nanoparticles was soaked in 10 mL of H2O2 at 90 °C for 6 h to modify the surface of the BTO nanoparticles, and then dried to obtain h-BTO powder.

[0014] (2) Take 0.025 g of the h-BTO powder prepared in step (1) and dissolve it in 10 mL of DMF. At the same time, take 0.225 g of P(VDF-TrFE) powder and dissolve it in another 10 mL of DMF. Then, mix the two DMF solutions evenly.

[0015] (3) The mixed solution in step (2) is spin-coated on a silicon template having a regular tetrahedral microarray, the size of the silicon template being 1 cm×1 cm, and dried at a constant temperature until solidified into a film, and then annealed at 120° C. for 2 h and then cooled. After cooling to room temperature, the composite film is peeled off from the silicon template.

[0016] (4) The two surfaces of the composite film obtained in step (3) are respectively plated with gold electrodes with a thickness of 100 nm, and each is connected with a lead wire to prepare a piezoelectric film with a regular tetrahedral microarray.

[0017] Furthermore, the regular tetrahedral microarray of the piezoresistive layer is prepared by the following method:

[0018] (1) PDMS and curing agent were mixed evenly in a mass ratio of 10:1 and vacuum-dried to remove bubbles;

[0019] (2) Spin-coating the PDMS with bubbles removed onto a silicon template having a regular tetrahedral microarray, the size of the silicon template being 1 cm×1 cm, drying at a constant temperature until solidified into a film, and peeling off the silicon template;

[0020] (3) 10 mL of 0.75 mg / mL graphene solution was drop-coated onto the PDMS surface with the microarray and the gold electrode surface, and dried. A lead was drawn out from each of the graphene surfaces to obtain a piezoresistive layer with a regular tetrahedral microarray.

[0021] Compared with the prior art, the present invention has the following beneficial effects: the data acquisition module used in the present application is a piezoelectric / piezoresistive dual-mode flexible sensor. From the perspective of the structure of the sensor itself, since the sensing signals of the piezoelectric layer and the piezoresistive layer are output through different electrodes, the mutual interference of the two sets of signals is avoided, and the accuracy of the collected pipeline fluid state related data is guaranteed. The dual-mode sensor enables the piezoelectric sensing mechanism and the piezoresistive sensing mechanism to cooperate with each other to complete the function that a single-mode sensor cannot achieve. It can not only detect static force changes, but also feedback high-frequency signal stimulation. In the process of detecting the force or deformation of the object, more information is obtained, combining the advantages of piezoelectric sensors and piezoresistive sensors. In terms of sensing performance, the sensing performance of the dual-mode sensor has not decreased, and because the dual-mode sensor is thinner and lighter than the single-mode combination sensor, the dual-mode sensor exhibits better sensing performance. The influence of the regular tetrahedral microarray in the sensor on the sensing performance of the piezoelectric layer is calculated and analyzed. When the geometric parameters k and h of the regular tetrahedral microstructure increase, the output voltage value of the piezoelectric layer increases and the sensitivity increases. The optimal microstructure, the pyramid microstructure, was determined, and a sensing layer with a pyramid microstructure array was prepared by the inverted film method, which can not only monitor the stress of the pipeline in real time, but also detect the flow rate of the fluid in real time. The intelligent pipeline has the characteristics of being able to monitor the speed, direction and flow state of the pipeline fluid in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a flowchart of the workflow of the intelligent pipeline of the present invention;

[0023] Figure 2 It is a working principle diagram of the piezoelectric / piezoresistive dual-mode sensor of the present invention;

[0024] Figure 3 Experimental data comparing the pressure and bending deformation sensing performance of dual-mode sensors and single-mode sensors;

[0025] Figure 4 It is a simulation effect diagram of the connection between the dual-mode sensor and the pipeline and the connection between each module;

[0026] Figure 5 It is a diagram of the overall and partial appearance of a piping system. DETAILED DESCRIPTION

[0027] like Figure 1 , 4As shown, an intelligent pipeline for fluid monitoring of the present invention includes: a pipeline, a data acquisition module, a data processing module, a wireless transmitting module, a wireless receiving module, a display screen and a power supply module. The power supply module, the data acquisition module and the wireless transmitting module are connected in sequence, the data acquisition module is vertically fixed to the inner wall of the pipeline, and the power supply module and the wireless transmitting module are sealed and fixed to the inner upper wall of the pipeline; the wireless receiving module, the data processing module and the display screen are connected in sequence and fixed to the outer side of the pipeline. The data acquisition module collects the electromechanical signal of the fluid in the pipeline, which is transmitted by the wireless transmitting module, and the electromechanical signal is received by the wireless receiving module. The electromechanical signal is then converted into flow rate data through signal processing by the data processing module, and finally displayed on the display screen.

[0028] The data acquisition module is a piezoelectric / piezoresistive dual-mode flexible sensor, such as Figure 2 As shown, it includes a piezoelectric layer and a piezoresistive layer; the piezoelectric layer is composed of a piezoelectric composite film with a microstructure and a gold electrode sprayed on the composite film; the piezoresistive layer is composed of a graphene film sprayed on the surface of the gold electrode with a microstructure and a PDMS with a microstructure; the microarray structure is a regular tetrahedral microarray. According to the constitutive equation of the piezoelectric effect:

[0029]

[0030]

[0031] where c ij 、e ij and k ij are the elastic stiffness constant, piezoelectric stress constant and dielectric constant, σ ij is stress, ε ij is the strain, D is the electric displacement, and E is the electric field intensity.

[0032] When the piezoelectric film is subjected to a normal force, σ11 and σ22 are both equal to 0. The above equations (2) and (3) are combined to express:

[0033]

[0034] Eliminating ε11, ε22 and ε33, we get:

[0035]

[0036] Where: D3 is the normal phase electric displacement,

[0037]

[0038]

[0039]

[0040] According to the relationship between electric field and electric potential:

[0041]

[0042] The normal electric displacement of the piezoelectric film is further obtained as:

[0043]

[0044] V is the output voltage of the piezoelectric film, and l is the thickness of the P(VDF-TrFE) film.

[0045] According to Maxwell's equations and Ohm's law, the magnitude of the current I is related to the electric displacement D3, the voltage V and the resistance R. According to the relationship between them:

[0046]

[0047]

[0048] Where t is time, A is the force area of ​​the piezoelectric film. After eliminating the current I and the electric displacement D3, we get:

[0049]

[0050] again

[0051]

[0052] According to the initial condition V (t＝0) =0, the output voltage V is:

[0053]

[0054] Where:

[0055]

[0056] In order to further improve the piezoelectric effect of the piezoelectric film, a regular tetrahedral micro-array structure is introduced on the surface of the planar film. Compared with the planar film structure, Figure 1 As shown, the cross-sectional area of ​​the tetrahedral structure in the vertical direction is different, and the normal stress σ on the piezoelectric film is 33 The stress in the vertical direction is equal, while the stress σ of the tetrahedron on the vertical section is 33 are different.

[0057] Let the length of the top side of the tetrahedron be a1, the length of the bottom side be h, and the height be h( Figure 1 ). Then the average stress of the tetrahedron can be expressed as:

[0058]

[0059] In the formula, the geometric parameter k is defined as a2 / a1. When k = 1, the area of ​​the top surface of the regular tetrahedron is equal to the area of ​​the bottom surface, and it can be regarded as a micro unit of the plane film. From formula (17), it can be seen that when the height h of the tetrahedron and the bottom side length a2 remain unchanged, the smaller the top side length a1 is, the greater the average stress σ' 33 In order to obtain the output voltage value between the upper and lower end faces of the regular tetrahedron, the average stress σ'33 is substituted into

[0060]

[0061] It follows that:

[0062]

[0063] From formula (1), it can be seen that the output voltage of the piezoelectric sensor is proportional to the geometric parameters k and height h of the regular tetrahedral microstructure. Therefore, in order to improve the sensing performance of the piezoelectric sensing layer, the area of ​​the top surface of the microstructure should be reduced as much as possible and the height of the microstructure should be increased. Therefore, when the regular tetrahedral is a pyramid structure, the sensing performance of the piezoelectric layer reaches the best. When the base of the pyramid microstructure is extended to 60μm, the maximum height that can be prepared by the current microstructure processing technology is 40μm.

[0064] The piezoelectric layer is prepared by the following method:

[0065] (1) 1 g of BTO nanoparticles was soaked in 10 mL of H2O2 at 90 °C for 6 h to modify the surface of the BTO nanoparticles, and then dried to obtain h-BTO powder.

[0066] (2) Take 0.025 g of the h-BTO powder prepared in step (1) and dissolve it in 10 mL of DMF. At the same time, take 0.225 g of P(VDF-TrFE) powder and dissolve it in another 10 mL of DMF. Then, mix the two DMF solutions evenly.

[0067] (3) The mixed solution in step (2) is spin-coated on a silicon template having a regular tetrahedral microarray, the size of the silicon template being 1 cm×1 cm, and dried at a constant temperature until solidified into a film, and then annealed at 120° C. for 2 h and then cooled. After cooling to room temperature, the composite film is peeled off from the silicon template.

[0068] (4) The two surfaces of the composite film obtained in step (3) are respectively plated with 100 nm thick gold electrodes using electron beam evaporation technology, and a lead wire is connected to each of them to prepare a piezoelectric film with a regular tetrahedral microarray.

[0069] The piezoresistive layer comprises the following preparation method:

[0070] (1) The PDMS used is model DC184 from Dow Corning, USA. The PDMS and curing agent are mixed evenly in a mass ratio of 10:1, and the bubbles are removed by vacuum;

[0071] (2) Spin-coating the PDMS with bubbles removed onto a silicon template having a regular tetrahedral microarray, the size of the silicon template being 1 cm×1 cm, drying at a constant temperature until solidified into a film, and peeling off the silicon template;

[0072] (3) 10 mL of 0.75 mg / mL graphene solution was drop-coated onto the PDMS surface with the microarray and the gold electrode surface, and dried. A lead was drawn out from the graphene surface to obtain a piezoresistive layer with a regular tetrahedral microarray.

[0073] Example

[0074] The data acquisition module of this embodiment is a piezoelectric / piezoresistive dual-mode flexible sensor, and its microarray structure adopts a pyramid-shaped microarray with a bottom side length of 60 μm and a height of 40 μm. Figure 2 The piezoelectric / piezoresistive dual-mode pressure sensor shown in the figure includes two parts: a piezoelectric layer and a piezoresistive layer. Gold electrodes are prepared on the upper and lower surfaces of the piezoelectric layer, and the piezoelectric signal output by the piezoelectric layer is connected to the voltmeter through the gold electrodes. A layer of rGO is covered on the microstructure surface of the piezoelectric layer and the piezoresistive layer. The piezoresistive signal is input to the ammeter through two layers of rGO. The sensing signals of the piezoelectric layer and the piezoresistive layer are output through different electrodes, avoiding mutual interference between the two sets of signals and ensuring the accuracy of the test.

[0075] In order to compare the performance of dual-mode sensors with that of single-mode sensors, a single-mode piezoresistive sensor and a piezoelectric sensor were attached together under the same experimental conditions, and the pressure and bending strain sensing performance of the combined sensor was tested. Figure 3 When testing the pressure loading rate, the internal resistance of the voltmeter is R = 10MΩ. Figure 3 As shown in (a), the minimum loading rate that the piezoelectric layer of the dual-mode sensor can sense is 0.1 kPa / s, and the sensitivity of the dual-mode sensor is S = 0.23, and the linearity is L = 0.98; the sensing sensitivity of the single-mode piezoelectric sensor is S = 0.18. The dual-mode sensor has a higher sensitivity when detecting the pressure loading rate. The bending strain detection performance of the two sensors is also compared. Figure 3 (b) shows that the sensing sensitivity of the piezoelectric layer in the dual mode is 0.18 V / (%s -1 ), the maximum detection strain rate is 10% s -1 The sensitivity of single-mode combined sensing is lower (0.12V / (%s -1 )), the maximum detection strain rate is 9% s -1. In addition, the sensing sensitivity of the piezoresistive layer to bending strain in the dual-mode sensor is 2.16, and the sensitivity of the single-mode combination sensor is 1.85. Therefore, in the bending strain detection experiment, the dual-mode sensor shows a better sensing performance than the single-mode combination sensor. In addition, according to further related experiments, through specific simulation of pipelines and joints, there is actually a linear relationship between the flow rate of the fluid in the pipeline and the strain rate of the sensor in the above data graph, that is, when the flow rate of the fluid in the pipeline is greater, the strain rate of the sensor (the ratio of the degree of change to the time of change) will also increase. On the contrary, when the flow rate is smaller, the corresponding strain rate will also decrease. Further, based on the relationship between the strain rate of the sensor and the sensing characteristics of the two different mode sensors, we can establish the relationship between the flow rate of the fluid in the pipeline and the signal monitored by the sensor and the output signal, which provides a basis for the monitoring of the entire pipeline system.

[0076] like Figure 5 As shown, first, the various connections of the pipeline diagram are numbered, so as to further describe the specific implementation method of this pipeline monitoring system from the whole. A certain fluid (gas or liquid) is introduced from the upper left pipe mouth in the figure, and it will pass through the various numbered connections through the pipeline. The signals of the fluid when it is stable are respectively monitored at ①②③④⑤ and converted into relevant data. At this time, the final results generated by the sensors in the five places transmitted to the PC end should be roughly the same. If at this time, the internal outlet of the pipeline at the connection of ②③④⑤ is adjusted or other reasons cause the speed and direction of the fluid in the pipeline to change to a certain extent, under this condition, the sensors at ②③④⑤ will not only monitor different fluid states and change the stable data, but also the sensor at ① will output different signal states. Through the collection and comparison of these signal changes that are finally output to the PC end, further computer analysis can finally monitor which numbered part of the pipeline state changes and cause the flow state of the fluid to change. Further, it can be analyzed which specific connection of the pipeline has problems or failures, so as to achieve the purpose of this intelligent pipeline monitoring system.

Claims

1. An intelligent pipeline for fluid monitoring, characterized in that ,include: Pipeline, data acquisition module, data processing module, wireless transmission module, wireless receiving module, display screen and power supply module; The power supply module, data acquisition module, and wireless transmission module are connected in sequence, the data acquisition module is vertically fixed to the inner wall of the pipeline, and the power supply module and the wireless transmission module are sealed and fixed to the inner upper wall of the pipeline; the wireless receiving module, the data processing module, and the display screen are connected in sequence and fixed to the outer side of the pipeline; the data acquisition module collects the force and electric signal of the fluid in the pipeline, which is transmitted by the wireless transmission module, and the force and electric signal is received by the wireless receiving module, and then the force and electric signal is converted into flow rate data through signal processing by the data processing module, and finally displayed on the display screen; The data acquisition module is a piezoelectric / piezoresistive dual-mode flexible sensor, which includes a piezoelectric layer and a piezoresistive layer; the piezoelectric layer is composed of a piezoelectric composite film with a microstructure and a gold electrode sprayed on the composite film; the piezoresistive layer is composed of a graphene film sprayed on the surface of the gold electrode with a microstructure and a PDMS with a microstructure; the microstructure is a regular tetrahedral microarray, and the ratio k of the side length of the upper bottom surface of the array to the side length of the lower bottom surface and the array height h satisfy: in, is the first variable, specifically is the second variable, specifically is the third variable, specifically c ij 、e ij and k ij are the elastic stiffness constant, piezoelectric stress constant and dielectric constant respectively; a2 is the side length of the bottom surface of the regular tetrahedron; F represents pressure, t is time, R is the internal resistance of the voltmeter, and V is the output voltage of the piezoelectric layer.

2. The smart pipeline according to claim 1, characterized in that: The regular tetrahedral microarray is a pyramid-shaped microarray.

3. The smart pipeline according to claim 1, characterized in that: The height of the regular tetrahedral microarray is h=40 μm.

4. The smart pipeline according to claim 1, characterized in that: The regular tetrahedral microarray of the piezoelectric layer is prepared by the following method: (1) 1 g of BTO nanoparticles were soaked in 10 mL of H2O2 at 90°C for 6 h to modify the surface of the BTO nanoparticles, and then dried to obtain h-BTO powder; (2) 0.025 g of the h-BTO powder prepared in step (1) was dissolved in 10 mL of DMF, and 0.225 g of the P(VDF-TrFE) powder was dissolved in another 10 mL of DMF, and then the two DMF solutions were mixed evenly; (3) Spin-coating the mixed solution in step (2) on a silicon template having a regular tetrahedral microarray, the size of the silicon template being 1 cm×1 cm, drying at a constant temperature until solidified into a film, annealing at 120° C. for 2 h, then cooling to room temperature, and peeling the composite film from the silicon template; (4) The two surfaces of the composite film obtained in step (3) are respectively plated with gold electrodes with a thickness of 100 nm, and each is connected with a lead wire to prepare a piezoelectric film with a regular tetrahedral microarray.

5. The smart pipeline according to claim 1, characterized in that: The regular tetrahedral microarray of the piezoresistive layer is prepared by the following method: (1) PDMS and curing agent were mixed evenly in a mass ratio of 10:1 and vacuum-dried to remove bubbles; (2) Spin-coating the PDMS with bubbles removed onto a silicon template having a regular tetrahedral microarray, the size of the silicon template being 1 cm×1 cm, drying at a constant temperature until solidified into a film, and peeling off the silicon template; (3) 10 mL of 0.75 mg / mL graphene solution was drop-coated onto the PDMS surface with the microarray and the gold electrode surface, and dried. A lead was drawn out from each of the graphene surfaces to obtain a piezoresistive layer with a regular tetrahedral microarray.

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