Non-ferromagnetic pipeline detection probe based on motional eddy current

Abstract

The utility model discloses a non-ferromagnetic pipeline detection probe based on dynamic eddy current, and relates to the technical field of pipeline detection, in particular to the non-ferromagnetic pipeline detection probe based on the dynamic eddy current, which comprises a U-shaped magnetic core and a non-ferromagnetic pipe wall, a first detection coil is arranged below the U-shaped magnetic core, and a second detection coil is arranged outside the rear portion of the U-shaped magnetic core. Through the cooperative arrangement of the U-shaped magnetic core, the excitation coil, the first detection coil and the second detection coil, the non-ferromagnetic pipeline detection probe based on the motional eddy current has the effect of effectively detecting internal and external defects of a non-ferromagnetic pipe wall at the same time; the non-ferromagnetic pipeline detection probe based on the motional eddy current has the effect of being convenient to operate.

Description

Technical Field

[0001] This utility model relates to the field of pipeline inspection technology, specifically a nonferromagnetic pipeline inspection probe based on motional eddy currents. Background Technology

[0002] Pipeline transportation has become one of the main modes of oil and gas transportation due to its good stability, economy, and efficiency. During its service life, corrosion pits are easily formed on the inner surface of the pipe wall due to the corrosive effect of the medium. In addition, longitudinal cracks along the pipe axis are also very likely to occur on the outer surface of the pipe wall. These defects usually expand over time and affect the mechanical properties and overall integrity of the metal structure. Therefore, non-destructive testing and evaluation of pipelines are of great significance. Electromagnetic non-destructive testing methods have the advantages of non-contact, high testing efficiency, and convenient signal processing, and are an extremely important non-destructive testing method for defects.

[0003] However, when pipelines have both surface cracks and internal corrosion pits, higher requirements are placed on pipeline quality inspection. Existing pipeline inspection methods mainly include radiographic testing, ultrasonic testing, magnetic particle testing, penetrant testing, and magnetic flux leakage testing, all of which have certain shortcomings. Radiographic testing equipment is inconvenient to carry, and the radiation can be harmful to the human body; ultrasonic testing is effective in detecting defects on the inner surface of pipelines, but has certain limitations in detecting defects on the outer surface; magnetic particle testing can only effectively detect surface and near-surface defects in ferromagnetic pipelines; penetrant testing can only detect surface opening defects; magnetic flux leakage testing is mainly suitable for ferromagnetic pipelines and is not applicable to non-ferromagnetic pipelines. Therefore, there is a need for a simple-to-operate detection probe that can effectively detect internal and external defects in non-ferromagnetic pipelines. Utility Model Content

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a non-ferromagnetic pipe inspection probe based on dynamic eddy currents, which solves the problems mentioned in the background section.

[0006] (II) Technical Solution

[0007] To achieve the above objectives, this utility model is implemented through the following technical solution: a nonferromagnetic pipe detection probe based on motional eddy currents, comprising a U-shaped magnetic core and a nonferromagnetic pipe wall, wherein an excitation coil is wound around the periphery of the U-shaped magnetic core, a first detection coil is disposed below the U-shaped magnetic core, and a second detection coil is disposed on the outer rear of the U-shaped magnetic core.

[0008] Preferably, the U-shaped magnetic core is made of a soft magnetic material with high magnetic permeability to enhance the strength and concentration of the magnetic field. The lower end faces of the two side legs of the U-shaped magnetic core are in contact with the outer surface of the non-ferromagnetic tube wall, and the horizontal part above the U-shaped magnetic core is parallel to the axial direction of the non-ferromagnetic tube wall.

[0009] Preferably, the excitation coil, the first detection coil, and the second detection coil are all wound with enameled wire, and the number of turns is determined according to the actual detection requirements to ensure appropriate magnetic field strength and detection sensitivity.

[0010] Preferably, both the first and second detection coils are connected to a signal processing circuit for detecting and converting magnetic field changes caused by defects in the non-ferromagnetic tube wall.

[0011] Preferably, the excitation coil is energized with direct current, thereby generating a constant magnetic field around the U-shaped magnetic core. The two side legs of the U-shaped magnetic core are equivalent to two magnetic poles. When the probe moves forward at a constant speed along the direction of the non-ferromagnetic tube wall, the magnetic field in the area behind the magnetic pole in the direction of movement will change. The magnetic field passes through the non-ferromagnetic tube wall and forms eddy currents on the surface of the non-ferromagnetic tube wall. The direction of the eddy currents is perpendicular to the plane of the paper. When there are no cracks or defects on the outer surface of the non-ferromagnetic tube wall, the first detection coil receives no magnetic field signal. When there are axial cracks on the outer surface of the non-ferromagnetic tube wall, the cracks will disturb the eddy currents on the outer surface of the non-ferromagnetic tube wall. The eddy currents will bypass the two ends of the crack and form a magnetic field perpendicular to the direction of the non-ferromagnetic tube wall. The size of the crack can be determined by the magnetic field signal perpendicular to the tube wall received by the first detection coil.

[0012] Preferably, when the probe moves forward at a constant speed along the direction of the non-ferromagnetic tube wall, the magnetic flux below the second detection coil changes, which will generate eddy currents in the non-ferromagnetic tube wall. If there are no corrosion pits inside the non-ferromagnetic tube wall, the magnetic field signal received by the second detection coil will not change. If there are corrosion pits inside the non-ferromagnetic tube wall, the corrosion pits will disturb the eddy currents below the non-ferromagnetic tube wall. The size of the corrosion pits inside the non-ferromagnetic tube wall can be determined by the change in the magnetic field received by the second detection coil.

[0013] This invention provides a nonferromagnetic pipe inspection probe based on dynamic eddy currents, which has the following advantages:

[0014] 1. This rapid detection probe for nonferromagnetic pipes based on motional eddy currents, through the coordinated arrangement of a U-shaped magnetic core, an excitation coil, a first detection coil, and a second detection coil, enables the probe to simultaneously and effectively detect defects inside and outside the nonferromagnetic pipe wall. The excitation coil, energized with direct current, generates a constant magnetic field around the U-shaped magnetic core. The two side legs of the U-shaped magnetic core act as two magnetic poles. When the probe moves forward at a constant speed along the nonferromagnetic pipe wall, the magnetic field behind the magnetic pole in the direction of movement changes. The magnetic field passing through the nonferromagnetic pipe wall forms eddy currents. Cracks on the outer surface of the pipe wall disrupt these eddy currents, and monitoring the changes in the eddy currents allows for the determination of the crack condition. Similarly, when the probe moves forward at a constant speed, eddy currents are formed in the pipe wall behind the magnetic pole in the direction of movement. Corrosion pits on the inner wall of the pipe wall disrupt these eddy currents, and monitoring the changes in the eddy currents allows for the determination of the corrosion pit condition.

[0015] 2. This rapid detection probe for non-ferromagnetic pipes based on motional eddy currents, through the combination of a U-shaped magnetic core and an excitation coil, achieves convenient operation. When the excitation coil is energized with direct current, a constant magnetic field is generated around the U-shaped magnetic core. When the probe moves, the magnetic field passes through the non-ferromagnetic pipe wall and forms eddy currents. These eddy currents are disturbed when they encounter discontinuities such as cracks and corrosion pits. Therefore, the detection can be completed simply by placing the probe on the outer side of the pipe and moving it along the axial direction, and then monitoring the changes in the eddy currents. This is very convenient. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model;

[0017] In the diagram: 1. U-shaped magnetic core; 2. Non-ferromagnetic tube wall; 3. Excitation coil; 4. First detection coil; 5. Second detection coil. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0019] Please see Figure 1This utility model provides a technical solution: a nonferromagnetic pipe detection probe based on motional eddy currents, comprising a U-shaped magnetic core 1 and a nonferromagnetic pipe wall 2. The U-shaped magnetic core 1 is made of a soft magnetic material with high magnetic permeability, such as silicon steel sheet, to enhance the strength and concentration of the magnetic field. The two side legs of the U-shaped magnetic core 1 are of the same length and are perpendicular to the upper horizontal portion. The lower end faces of the two side legs of the U-shaped magnetic core 1 are in contact with the outer surface of the nonferromagnetic pipe wall 2. The upper horizontal portion of the U-shaped magnetic core 1 is parallel to the axial direction of the nonferromagnetic pipe wall 2. An excitation coil 3 is wound around the periphery of the U-shaped magnetic core 1. A first [missing information - likely a device or structure] is provided below the U-shaped magnetic core 1. A second detection coil 5 is located outside the U-shaped magnetic core 1, behind the detection coil 4. The excitation coil 3, the first detection coil 4, and the second detection coil 5 are all wound with enameled wire, and the number of turns is determined according to actual detection requirements to ensure appropriate magnetic field strength and detection sensitivity. Both the first detection coil 4 and the second detection coil 5 are connected to signal processing circuits to detect and convert the magnetic field change signal caused by the defect in the non-ferromagnetic tube wall 2. The excitation coil 3 is energized with direct current, thereby generating a constant magnetic field around the U-shaped magnetic core 1. The two side legs of the U-shaped magnetic core are equivalent to two magnetic poles. When the probe moves along the non-ferromagnetic tube wall 2... When moving forward at a constant speed, the magnetic field behind the magnetic pole in the direction of movement will change. The magnetic field passes through the non-ferromagnetic tube wall 2 and forms eddy currents on the surface of the non-ferromagnetic tube wall 2. The direction of the eddy currents is perpendicular to the plane of the paper. When there are no cracks or defects on the outer surface of the non-ferromagnetic tube wall 2, the first detection coil 4 receives no magnetic field signal. When there are axial cracks on the outer surface of the non-ferromagnetic tube wall 2, the cracks will disturb the eddy currents on the outer surface of the non-ferromagnetic tube wall 2. The eddy currents will bypass the two ends of the cracks and form a magnetic field perpendicular to the direction of the non-ferromagnetic tube wall 2. The magnetic field perpendicular to the direction of the tube wall is received by the first detection coil 4. The magnetic field signal can be used to determine the size of the crack. When the probe moves forward at a constant speed along the direction of the non-ferromagnetic tube wall 2, the magnetic flux below the second detection coil 5 changes, which will form eddy currents in the non-ferromagnetic tube wall 2. If there are no corrosion pits inside the non-ferromagnetic tube wall 2, the magnetic field signal received by the second detection coil 5 will not change. If there are corrosion pits inside the non-ferromagnetic tube wall 2, the corrosion pits will disturb the eddy currents below the non-ferromagnetic tube wall 2. The size of the corrosion pits inside the non-ferromagnetic tube wall 2 can be determined by the change in the magnetic field received by the second detection coil 5.

[0020] In use, the excitation coil 3 is connected to a DC excitation power supply. When the DC excitation power supply is powered on, a constant magnetic field is generated around the excitation coil 3. The detection probe is then brought close to or directly attached to the outer surface of the non-ferromagnetic tube, ensuring that the top of the U-shaped magnetic core 1 is parallel to the axis of the non-ferromagnetic tube. The constant magnetic field generated around the excitation coil 3 will then pass through the non-ferromagnetic tube being tested. As the probe moves forward at a constant speed along the tube wall, the magnetic field behind the magnetic poles in the direction of movement will change, generating eddy currents in the tube. The direction of these eddy currents is perpendicular to the plane of the paper. When there are no cracks or defects on the outer surface of the tube, the eddy currents are always perpendicular to the plane of the paper. When there are axial cracks on the outer surface of the tube, the cracks will disturb the eddy currents on the tube wall surface, causing the eddy currents to bypass the crack ends and form a magnetic field perpendicular to the tube wall. At this time, the first detection coil 4 can receive this magnetic field signal perpendicular to the tube wall. The signal processing circuit converts and amplifies the magnetic field signal received by the first detection coil 4, such as converting it into a current signal and amplifying it. One hundred times, at this time, the size of the crack can be determined by reading the current change of the signal processing circuit through the ammeter. When the probe moves forward at a constant speed along the direction of the non-ferromagnetic tube wall 2, the magnetic flux below the second detection coil 5 will change, thereby forming eddy currents in the non-ferromagnetic tube wall 2. If there are no corrosion pits inside the non-ferromagnetic tube wall 2, the size of the eddy currents formed in the non-ferromagnetic tube wall 2 will not change, that is, the second detection coil 5 can detect a stable eddy current signal. At this time, the signal processing circuit connected to the second detection coil 5 can read a stable current signal through the ammeter. When there are corrosion pits inside the non-ferromagnetic tube wall 2, the corrosion pits will disturb the eddy currents below the non-ferromagnetic tube wall 2. At this time, the magnetic flux passing through the second detection coil 5 will change, that is, the signal processing circuit connected to the second detection coil 5 will show a change in magnetic induction intensity. The size of the current signal read by the ammeter will also change. At this time, the size of the corrosion pit on the inner wall of the non-ferromagnetic tube wall 2 can be determined by the change in current.

[0021] In summary, the excitation coil 3 of this non-ferromagnetic pipe inspection probe based on motional eddy currents generates a constant magnetic field around the U-shaped magnetic core 1 when a direct current is applied to it. When the probe moves forward at a constant speed along the non-ferromagnetic pipe wall 2, the magnetic field behind the magnetic pole in the direction of movement will change. The magnetic field passing through the non-ferromagnetic pipe wall 2 can form eddy currents. Cracks on the outer surface of the pipe wall will disturb the eddy currents, and by monitoring the changes in the eddy currents, the condition of the cracks can be determined. When the probe moves forward at a constant speed, eddy currents will be formed in the pipe wall. Corrosion pits on the inner wall of the pipe will disturb the eddy currents, and by monitoring the changes in the eddy currents, the condition of the corrosion pits can be determined. In this process, it is very convenient to simply place the inspection probe on the outer side of the pipe and move it along the axial direction and then monitor the changes in the eddy currents.

[0022] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A nonferromagnetic pipe detection probe based on motional eddy currents, comprising a U-shaped magnetic core (1) and a nonferromagnetic pipe wall (2), characterized in that: The U-shaped magnetic core (1) is surrounded by an excitation coil (3), a first detection coil (4) is provided below the U-shaped magnetic core (1), and a second detection coil (5) is provided on the outside of the rear of the U-shaped magnetic core (1).

2. The nonferromagnetic pipe inspection probe based on motional eddy currents according to claim 1, characterized in that: The U-shaped magnetic core (1) is made of soft magnetic material with high permeability to enhance the strength and concentration of the magnetic field. The lower end face of the two side legs of the U-shaped magnetic core (1) is in contact with the outer surface of the non-ferromagnetic tube wall (2). The horizontal part above the U-shaped magnetic core (1) is parallel to the axial direction of the non-ferromagnetic tube wall (2).

3. The nonferromagnetic pipe inspection probe based on motional eddy currents according to claim 1, characterized in that: The excitation coil (3), the first detection coil (4) and the second detection coil (5) are all wound with enameled wire, and the number of turns is determined according to the actual detection requirements to ensure appropriate magnetic field strength and detection sensitivity.

4. The nonferromagnetic pipe inspection probe based on motional eddy currents according to claim 1, characterized in that: Both the first detection coil (4) and the second detection coil (5) are connected to a signal processing circuit, which is used to detect and convert the magnetic field change signal caused by the defect in the non-ferromagnetic tube wall (2).

5. The nonferromagnetic pipe inspection probe based on motional eddy currents according to claim 1, characterized in that: The excitation coil (3) is energized with direct current, thereby generating a constant magnetic field around the U-shaped magnetic core (1). The two side legs of the U-shaped magnetic core are equivalent to two magnetic poles. When the probe moves forward at a constant speed along the direction of the non-ferromagnetic tube wall (2), the magnetic field behind the magnetic pole in front of the moving direction will change. The magnetic field passes through the non-ferromagnetic tube wall (2) and forms eddy currents on the surface of the non-ferromagnetic tube wall (2). The direction of the eddy currents is perpendicular to the plane of the paper. When there are no cracks or defects on the outer surface of the non-ferromagnetic tube wall (2), the first detection coil (4) receives no magnetic field signal. When there are axial cracks on the outer surface of the non-ferromagnetic tube wall (2), the cracks will disturb the eddy currents on the outer surface of the non-ferromagnetic tube wall (2). The eddy currents will bypass the two ends of the crack and form a magnetic field perpendicular to the direction of the non-ferromagnetic tube wall (2). The size of the crack can be determined by the magnetic field signal perpendicular to the direction of the tube wall received by the first detection coil (4).

6. The nonferromagnetic pipe inspection probe based on motional eddy currents according to claim 1, characterized in that: When the probe moves forward at a constant speed along the direction of the nonferromagnetic tube wall (2), the magnetic flux below the second detection coil (5) changes, which will form eddy currents in the nonferromagnetic tube wall (2). If there are no corrosion pits inside the nonferromagnetic tube wall (2), the magnetic field signal received by the second detection coil (5) will not change. If there are corrosion pits inside the nonferromagnetic tube wall (2), the corrosion pits will disturb the eddy currents below the nonferromagnetic tube wall (2). The size of the corrosion pits inside the nonferromagnetic tube wall (2) can be determined by the change in the magnetic field received by the second detection coil (5).

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