Patent ID: 12259312

In the drawings,1, magnetizing device;2, RFID tag sensor;3, pipeline;4, reader;11, armature;12, first permanent magnet;13, first pole shoe;14, second permanent magnet;15, second permanent magnet;21, metal ground plate;22, dielectric substrate;23, metal radiation patch;24, ultra-high frequency RFID chip;41, reader antenna.

DETAILED DESCRIPTION OF EMBODIMENTS

This application will be described in detail below with reference to the following embodiments and accompanying drawings, so as to facilitate the understanding of this application. It should be noted that the embodiments are merely illustrative, and not intended to limit this application. Any variations made by those skilled in the art without departing from the spirit and scope of the application should fall within the scope of the application defined by the appended claims.

Referring to an embodiment shown inFIG.1, a system for monitoring corrosion on an inner wall of a pipeline based on radio-frequency identification (RFID) is provided herein. The system includes a magnetizing device1, a RFID tag sensor2, and a reader4. The magnetizing device1is placed on a pipeline3. The magnetizing device1includes an armature11, a first permanent magnet12, a first pole shoe13, a second permanent magnet14and a second pole shoe15. The first pole shoe13and the second pole shoe15are arranged on an outer wall of the pipeline3. The first permanent magnet12is located above the first pole shoe13, and is fixedly connected to the first pole shoe13. The second permanent magnet14is located above the second pole shoe15, and is fixedly connected to the second pole shoe15. The armature11is located above the first permanent magnet12and the second permanent magnet14. One end of the armature11is fixedly connected to the first permanent magnet12, and the other end of the armature11is fixedly connected to the second permanent magnet14.

The RFID tag sensor2is placed on the pipeline3, and located on the same side as the magnetizing device1. Referring to an embodiment shown inFIG.2, the RFID tag sensor2includes an ultra-high frequency (UHF) RFID chip24and a permeability-sensitive antenna. The permeability-sensitive antenna includes a metal ground plate21, a dielectric substrate22and a metal radiation patch23. The dielectric substrate22is made of a glass-reinforced epoxy laminate composite material. A first surface of the dielectric substrate22is fixedly connected to the metal ground plate21, and a second surface of the dielectric substrate22is fixedly connected to the metal radiation patch23. A microstrip structure is provided in a middle of the metal radiation patch23. An end of the microstrip structure is fixedly connected to the UHF RFID chip24. A length direction of the permeability-sensitive antenna is perpendicular to a magnetization direction of the magnetizing device1. An impedance of the permeability-sensitive antenna is conjugate with an impedance of the UHF RFID chip24.

The reader4is in wireless communication connection with the RFID tag sensor2through a reader antenna41.

In this embodiment, the magnetizing device1is provided on the pipeline3, and is configured to form a complete magnetic circuit with the pipeline3, so as to magnetize the pipeline3. When the internal corrosion of the pipeline3occurred, the internal corrosion will lead to magnetic distortion, thereby resulting in the disturbance of a magnetic permeability on the surface of the pipeline3. The RFID tag sensor2attached to the pipeline3is configured to monitor the internal corrosion of the pipeline3via detecting the disturbance of the magnetic permeability on the surface of the pipeline3, so as to obtain monitored data. The monitored data is transmitted to the reader4via wireless signals to realize a data exchange.

This application is based on the following scientific principles.

According to the skin effect, a skin depth where the current loss is concentrated in the pipeline3is calculated as follows:

δ=1π⁢f⁢μσ;

where μ is the magnetic permeability; δ is an electric conductivity; f is a frequency. It can be implied that the resonant frequency shift (RFS) of the permeability-sensitive antenna of the RFID tag sensor2reflects a change in material properties around an area where the surface crack and the internal corrosion of the pipeline3occurs.

An expression of the resonant frequency of the RFID tag sensor2is as follows:

fres=c4⁢εre·1L+Δ⁢Loc;εre=εr+12+εr-12⁢1+10⁢h/W;Δ⁢Loc=0.412h⁢(εre+0.3)⁢(Wh+0.264)(εre-0.258)⁢(Wh+0.813);where c is a light velocity; εreis an effective dielectric constant; L is a length of the metal radiation patch23; ΔLocis a compensation length; εris a dielectric coefficient; h is a thickness of the dielectric substrate22; and W is a width of the metal radiation patch23.

When the corrosion occurred inside the material of the pipeline3, metal and air will disturb the magnetic field distribution due to the difference in material properties. After magnetic field lines are compressed, one part of the magnetic field lines passes through a space above the corrosion in the pipeline, and the other part of the magnetic field lines leaks into the air on the other side of the corrosion. According to magnetic field distribution, a magnetic field intensity H above the corrosion is intensified. Considering that a variation of the magnetic field is corresponding to the different positions on a μ-H curve of a ferromagnetic material, the uneven distribution of the magnetic field caused by the internal corrosion of the pipeline3will lead to the disturbance of the magnetic permeability on the surface of the pipeline3, such that the internal corrosion is transformed into the disturbance of the magnetic permeability monitored by the RFID tag sensor2.

A microstrip structure is provided to ensure an anti-metal performance of the permeability-sensitive antenna. During operation, the permeability-sensitive antenna is placed on an outer surface of the pipeline3. The outer surface of the pipeline3is configured to be a ground plane of the permeability-sensitive antenna to monitor the magnetic distortion resulted from the internal corrosion of the pipeline.

The magnetic field disturbance caused by the internal corrosion of the pipeline3in a magnetized state will cause the disturbance of the magnetic permeability on the surface of the pipeline. Under the same intensity of magnetization, the magnetic permeability of a surface area of the pipeline3where the internal corrosion occurs increases as a corrosion burial depth increases. The disturbance of the magnetic permeability is allowed to be determined by the resonant frequency or the resonant frequency shift (RFS) of the permeability-sensitive antenna, and thus the RFS increases with the increase of the depth of the internal corrosion of the pipeline3. The magnetic field lines are compressed due to the defects, such that the magnetic intensity of the skin depth layer of the pipeline is intensified, and an area directly facing the crack defect has the maximum magnetic intensity. In addition, the shallower the corrosion burial depth, the greater the magnetic field variations.

The permeability-sensitive antenna is designed for the UHF band, and is configured to transform the internal corrosion of the pipeline into the disturbance of the magnetic permeability to be detected by the UHF RFID chip24. The specific dimensions (dimension indication is shown inFIG.3) of the permeability-sensitive antenna are designed as exhibited in Table 1.

TABLE 1Specific dimensions of permeability-sensitive antenna (mm)LWLiWiLcWh694741921.32

The impedance of the permeability-sensitive antenna is conjugated with the impedance of the UHF RFID chip, so as to match the impedance of the permeability-sensitive antenna and the impedance of the UHF RFID chip, optimizing the signal transmission quality.

In conclusion, compared with the prior art, the system provided herein has the advantages of light structure, low cost, high monitoring accuracy, simple assembly and disassembly and convenient maintenance, and the RFID tag sensor has the advantages of passive wireless and maintenance-free, lowering the cost, and facilitating the application of the technology of monitoring the internal corrosion of the pipeline, and has a huge application prospect.

The principles and implementations of this application are illustrated by the description of the specific embodiments. Described above is merely used to help understand the method and the core idea of this application. For those skilled in the art, any changes of the embodiments and application scopes can be made according the spirit of the application. In conclusion, this description should not be understood as limitations of this application.

It should be understood by those of ordinary skill in the art that the embodiments described above are merely intended to facilitate the understanding of the principles of this application, but not to limit this application. It should be understood that any modifications and combinations made by those skilled in the art without departing from the spirit and scope of the application should fall within the scope of the application defined by the appended claims.