Coupling and differential combined pulsed eddy current measuring probe
By designing a pulsed eddy current measurement probe that combines coupling and differential methods, and integrating a transmitting coil, a coupled receiving coil, and a differential receiving coil, the problem of not being able to simultaneously detect metal loss and shallow cracks in existing technologies has been solved, enabling accurate detection of bare tubes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- QINGDAO SHANKE MARINE ENVIRONMENTAL ENGINEERING CO LTD
- Filing Date
- 2025-04-14
- Publication Date
- 2026-05-08
AI Technical Summary
Existing pulsed eddy current technology cannot simultaneously and accurately detect metal loss and shallow cracks within the magnetic field coverage area. Especially in the inspection of bare pipes in high-risk locations, it is impossible to quantitatively analyze metal loss and qualitatively determine shallow cracks.
Design a pulsed eddy current measurement probe that combines coupling and differential methods, including a transmitting coil, a coupled receiving coil, and a differential receiving coil. The coupled receiving coil is used to semi-quantitatively measure metal loss, while the differential receiving coil is used to qualitatively determine shallow cracks, thus achieving simultaneous detection of bare tubes.
It enables semi-quantitative measurement of metal loss in bare tubes and qualitative judgment of shallow cracks, improving the accuracy and sensitivity of detection and meeting the detection needs of high-risk locations.
Smart Images
Figure CN224216627U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of pulse eddy current detection technology, specifically relating to a pulse eddy current measurement probe that combines coupling and differential methods. Background Technology
[0002] The statements herein provide only background information related to this invention and do not necessarily constitute prior art.
[0003] The materials used in most pressure vessels and pipelines in the petrochemical industry are ferromagnetic. Under conditions of high temperature, high pressure, high sulfur content, and acid / alkali content, the inner walls of these vessels will experience metal loss or corrosion thinning as the equipment's service life increases. Common types of corrosion include large-area uniform thinning, large-area localized erosion thinning, and small-area but deep thinning. This metal loss is the main cause of penetration leaks in equipment. Once a pressure vessel or pressure pipeline leaks, it can lead to serious or even catastrophic consequences.
[0004] Pulsed eddy current testing utilizes the principle of electromagnetic induction and is a non-contact, non-destructive testing method. It eliminates the need for rust and paint removal, metal grinding, and coupling agents, and is effective against both high and low temperatures. Specifically designed for ferromagnetic bare pipes, it can accurately detect internal and external corrosion defects, pinpoint their location, and roughly estimate the remaining corrosion. This technology plays a positive supplementary role in corrosion management within the petrochemical industry. It has been widely applied in refining, chemical, power plant, and nuclear industries, and its advanced technology ensures rapid location and approximate estimation of corrosion defects and the extent of corrosion in pipelines and containers.
[0005] The inventors discovered that existing pulsed eddy current technology primarily targets the detection of relative wall thickness anomalies in coated steel tanks or pipes, and its spatial resolution is directly related to the lift-off height. The greater the probe lift-off height, the lower the spatial resolution (i.e., the lower the sensitivity in detecting the size of corrosion pits). For some special high-risk locations, precise detection of relative wall thickness changes and identification of shallow cracks is required. In such cases, insulation needs to be removed, and pulsed eddy current technology can be used for precise detection of internal wall corrosion and identification of shallow cracks in high-risk locations of bare pipes. However, existing pulsed eddy current technology only performs qualitative and semi-quantitative detection of metal loss within the probe's magnetic field coverage area, and cannot simultaneously perform qualitative analysis of shallow cracks on the steel surface within the magnetic field coverage area. Utility Model Content
[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a pulsed eddy current measurement probe that combines coupling and differential measurement. During the measurement process, this probe can semi-quantitatively measure the relative average wall thickness change within the magnetic field coverage area of the probe's transmitting coil, and qualitatively measure the basic condition of shallow large cracks within the magnetic field coverage area of the transmitting coil. It can detect metal loss in bare tubes and simultaneously make qualitative judgments on shallow cracks.
[0007] To achieve the above objectives, this utility model is implemented through the following technical solution:
[0008] The present invention provides a pulsed eddy current measurement probe combining coupling and differential methods, comprising: a housing, wherein a transmitting coil, a coupling receiving coil, and a differential receiving coil are disposed within the housing; the transmitting coil and the coupling receiving coil are concentrically coupled, and the differential receiving coil is disposed inside the transmitting coil; a multi-core quick connector is disposed on the housing, and the transmitting coil, the coupling receiving coil, and the differential receiving coil are respectively connected to the multi-core quick connector via leads; the multi-core quick connector is connected to a pulsed eddy current host.
[0009] In at least one embodiment, the concentric coupling of the transmitting coil and the coupled receiving coil specifically means that the transmitting coil and the coupled receiving coil are concentrically nested, and the coupled receiving coil is disposed outside the transmitting coil.
[0010] In at least one embodiment, the differential receiving coil is composed of a first coil and a second coil connected in parallel.
[0011] In at least one embodiment, the multi-core quick connector has at least six copper cores.
[0012] In at least one embodiment, the transmitting coil, the coupled receiving coil, and the differential receiving coil are each provided with at least two leads and are respectively connected to the copper cores at different positions of the multi-core quick connector.
[0013] In at least one embodiment, the pulsed eddy current host is a dual-channel pulse transmitter and receiver.
[0014] In at least one embodiment, the multi-core quick-connect is connected to the pulse eddy current host via a coaxial cable.
[0015] In at least one embodiment, the shape of the transmitting coil and the coupling receiving coil is circular, square, rhomboid, or polygonal.
[0016] In at least one embodiment, the first coil and the second coil are circular, square, rhomboid, or polygonal in shape.
[0017] In at least one embodiment, the wire diameter protection range of the enameled wire wound around the transmitting coil, the coupled receiving coil, and the differential receiving coil is 0.1-2.0 mm.
[0018] The beneficial effects of the above-described technical solution of this utility model are as follows:
[0019] This invention provides a pulsed eddy current measurement probe that combines coupling and differential methods. During the measurement process, the coupling receiving coil provides the pulsed eddy current host with an analysis signal of metal loss within the measurement magnetic field coverage area, while the differential receiving coil provides the pulsed eddy current host with an analysis signal of the approximate condition of shallow cracks within the measurement magnetic field coverage area. This achieves pulsed eddy current detection combining coupling and differential methods. It can semi-quantitatively measure the relative average wall thickness change within the magnetic field coverage area of the probe's transmitting coil, and qualitatively measure the basic condition of shallow large cracks within the magnetic field coverage area of the transmitting coil. It can detect metal loss in bare tubes and simultaneously make qualitative judgments on shallow cracks. Attached Figure Description
[0020] The accompanying drawings, which form part of this specification, are used to provide a further understanding of this utility model. The illustrative embodiments of this utility model and their descriptions are used to explain this utility model and do not constitute an improper limitation of this utility model.
[0021] Figure 1 This is an overall schematic diagram of a pulse eddy current measurement probe that combines coupling and differential methods according to this utility model;
[0022] Figure 2 This is a schematic diagram of the internal structure of a pulse eddy current measurement probe that combines coupling and differential methods according to this utility model.
[0023] In the diagram: 1. Probe; 2. Pulsed eddy current generator; 3. Housing; 4. Transmitting coil; 5. Coupled receiving coil; 6. Differential receiving coil; 7. Multi-core quick connector; 8. Pipe or container.
[0024] The distances or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only. Detailed Implementation
[0025] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0026] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to the present invention. As used herein, unless otherwise expressly indicated by the present invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0027] Terminology Explanation: The terms "installation," "connection," "linking," and "fixing" in this utility model should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction relationship between two components. For those skilled in the art, the specific meaning of the above terms in this utility model can be understood according to the specific circumstances.
[0028] As described in the background section, the purpose of this invention is to overcome the shortcomings of the prior art and provide a pulsed eddy current measurement probe that combines coupling and differential measurement. During the measurement process, this probe can semi-quantitatively measure the relative average wall thickness change within the magnetic field coverage area of the probe's transmitting coil, and qualitatively measure the basic condition of shallow large cracks within the magnetic field coverage area of the transmitting coil. It can detect metal loss in bare tubes and simultaneously make qualitative judgments on shallow cracks.
[0029] Example 1
[0030] In a typical embodiment of this utility model, such as Figure 1 and Figure 2 As shown, this embodiment discloses a pulsed eddy current measurement probe 1 that combines coupling and differential methods. It is used for scanning and detecting uncoated ferromagnetic material pipes (bare pipes) using pulsed eddy current. When in use, it is placed on the pipe or container 8 and includes: a housing 3, in which a transmitting coil 4, a coupling receiving coil 5, and a differential receiving coil 6 are disposed; the transmitting coil 4 and the coupling receiving coil 5 are concentrically coupled, and the differential receiving coil 6 is disposed inside the transmitting coil 4; a multi-core quick connector 7 is disposed on the housing 3, and the transmitting coil 4, the coupling receiving coil 5, and the differential receiving coil 6 are respectively connected to the multi-core quick connector 7 through leads; the multi-core quick connector 7 is connected to the pulsed eddy current host 2.
[0031] In this embodiment, the pulsed eddy current generator 2 sends an excitation signal to the transmitting coil 4 of the probe 1 to generate a pulsed magnetic field. The coupled receiving coil 5 and the differential receiving coil 6 respectively receive the eddy current induced magnetic field and the differential signal of the magnetic field change generated by the transmitting coil 4, and transmit them to the pulsed eddy current generator 2 (dual-channel pulsed eddy current generator). The voltage attenuation signal provided by the coupled receiving coil 5 is used to calculate the slope characteristic value at the end of the signal using existing algorithms, which can measure the amount of metal loss (relative wall thickness) within the magnetic field coverage area. The differential voltage signal provided by the differential receiving coil 6 (when the probe scans, the differential probe generates an N-shaped voltage fluctuation from negative to positive before and after the crack) can be used to qualitatively determine the approximate condition of the shallow crack within the magnetic field coverage area. The calculation of the slope characteristic value at the end of the signal using the existing algorithm refers to calculating the single logarithmic slope of the voltage versus time at the three time window points at the inflection point of the attenuated signal end (the vertical axis is the logarithmic voltage and the horizontal axis is the time). The inflection point position is calculated by using the double logarithmic slope value (the vertical axis is the logarithmic voltage and the horizontal axis is the logarithmic time) which is greater than the threshold of 1.5.
[0032] In this embodiment, the transmitting coil 4 and the coupled receiving coil 5 are concentrically nested, meaning that the transmitting coil 4 and the coupled receiving coil 5 are placed together coaxially, with the coupled receiving coil 5 located outside the transmitting coil 4 and the transmitting coil 4 located inside. This coaxial coupling of the coupled receiving coil 5 and the transmitting coil 4 allows for more effective capture of magnetic field changes caused by eddy current attenuation in the measured material, improving detection accuracy. Simultaneously, the coaxial coupling also increases the stability of the induced signal, thereby reducing the algorithmic complexity of capturing the final signal.
[0033] In this embodiment, the differential receiving coil 6 is composed of a first coil and a second coil connected in parallel. The first and second coils have essentially the same composition. To facilitate placement inside the transmitting coil 4, the first and second coils are relatively small in size, and their parallel connection forms the differential receiving coil 6, which is then placed inside the transmitting coil 4. By placing the differential receiving coil 6 inside the transmitting coil 4, the transmitting coil 4 excites attenuated eddy currents within the material. When the moving probe passes through the shallow crack region of the material, the magnetic field distortion generated by the attenuation of the eddy currents within the material is more easily captured, producing a significant N-shaped voltage fluctuation, thereby improving the sensitivity of qualitative judgment of near-surface cracks.
[0034] In this embodiment, the multi-core quick connector 7 has at least six copper cores (two leads for the transmitting coil 4, two leads for the coupled receiving coil 5, and two leads for the differential receiving coil 6). The transmitting coil 4, coupled receiving coil 5, and differential receiving coil 6 each have two leads, connected to copper cores at different locations on the multi-core quick connector 7, thus connecting the transmitting coil 4 and all receiving coils to the multi-core quick connector 7. In this embodiment, the multi-core quick connector 7 uses a six-core quick connector, with the two leads of the transmitting coil 4, the two leads of the coupled receiving coil 5, and the two leads of the differential receiving coil 6 connected to copper cores at different locations on the six-core quick connector. The number of copper cores in the multi-core quick connector 7 is related to the number of coils; for each additional coil, two more cores are required. If there are more than six cores, the other cores can be soldered to devices such as a start button or a light on a probe.
[0035] In this embodiment, the pulsed eddy current host 2 is a dual-channel pulse transmitter and receiver, namely a transmitter and dual receiver host, that is, one transmitter channel and two receiver channels. Among the two receiver channels, one channel receives the voltage attenuation signal (the end slope is used to calculate the wall thickness value) provided by the coupled receiving coil 5, and the other channel receives the N-shaped voltage fluctuation signal provided by the differential receiving coil 6 when the probe moves through the shallow crack, so as to qualitatively determine the approximate condition of the shallow crack within the magnetic field coverage area.
[0036] In this embodiment, the multi-core quick connector 7 is connected to the pulse eddy current host 2 via a coaxial cable, thereby realizing the connection between the measurement probe 1 and the pulse eddy current host 2.
[0037] In this embodiment, the transmitting coil 4 and the coupled receiving coil 5 are circular, square, rhomboid, or polygonal in shape; the first and second coils connected in parallel to form the differential receiving coil 6 are circular, square, rhomboid, or polygonal in shape. Furthermore, the wire diameter of the enameled wire wound around the transmitting coil 4, coupled receiving coil 5, and differential receiving coil 6 is protected within the range of 0.1-2.0 mm.
[0038] In this embodiment, the specific working principle of a pulse eddy current measurement probe 1 that combines coupling and differential is as follows:
[0039] During the measurement process of the moving probe 1, the pulse eddy current host 2 is provided with an analysis signal of the voltage attenuation of metal loss within the measurement magnetic field coverage area through the internal coupling receiving coil 5 of the probe, and the slope at the end of the signal is obtained by the algorithm to calculate the relative wall thickness value; the pulse eddy current host 2 is provided with an analysis signal of the approximate condition of shallow cracks within the measurement magnetic field coverage area through the differential receiving coil 6, and the approximate condition of shallow cracks within the magnetic field coverage area is determined by splitting the N-shaped voltage fluctuation value generated by the probe passing through the shallow crack.
[0040] This invention provides a pulsed eddy current measurement probe 1 that combines coupling and differential methods. During the measurement process, the coupling receiving coil 5 provides the pulsed eddy current host 2 with an analysis signal of metal loss within the measurement magnetic field coverage area, and the differential receiving coil 6 provides the pulsed eddy current host 2 with an analysis signal of the approximate condition of shallow cracks within the measurement magnetic field coverage area. This achieves pulsed eddy current detection that combines coupling and differential methods. It can semi-quantitatively measure the relative average wall thickness change within the magnetic field coverage area of the probe's transmitting coil, and qualitatively measure the basic condition of shallow large cracks within the magnetic field coverage area of the transmitting coil.
[0041] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.
Claims
1. A pulsed eddy current measurement probe combining coupling and differential methods, characterized in that, Includes: a housing, wherein a transmitting coil, a coupled receiving coil, and a differential receiving coil are disposed within the housing; The transmitting coil and the coupled receiving coil are concentrically coupled, and the differential receiving coil is disposed inside the transmitting coil; a multi-core quick connector is provided on the housing, and the transmitting coil, the coupled receiving coil and the differential receiving coil are respectively connected to the multi-core quick connector through leads; the multi-core quick connector is connected to the pulse eddy current host.
2. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The concentric coupling of the transmitting coil and the coupling receiving coil is specifically defined as follows: the transmitting coil and the coupling receiving coil are concentrically nested, and the coupling receiving coil is located outside the transmitting coil.
3. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The differential receiving coil is composed of a first coil and a second coil connected in parallel.
4. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The multi-core quick connector has at least six copper cores.
5. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The transmitting coil, the coupled receiving coil, and the differential receiving coil are each provided with at least two leads, which are respectively connected to the copper cores at different positions of the multi-core quick connector.
6. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The pulsed eddy current host is a dual-channel pulse transmitter and receiver.
7. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The multi-core quick connector is connected to the pulse eddy current host via a coaxial cable.
8. The pulse eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The transmitting coil and the coupling receiving coil are circular, square, rhomboid, or polygonal in shape.
9. A pulse eddy current measurement probe combining coupling and differential as described in claim 3, characterized in that, The first and second coils are circular, square, rhomboid, or polygonal in shape.
10. A pulsed eddy current measurement probe combining coupling and differential as described in claim 1, characterized in that, The wire diameter protection range for the enameled wire wound around the transmitting coil, the coupled receiving coil, and the differential receiving coil is 0.1-2.0 mm.