Rotating eddy current detection device, rotation speed measurement method, and eddy current detection method

Abstract

This invention discloses a rotating eddy current detection device, a speed measurement method, and an eddy current detection method. The device includes: an eddy current meter, a first housing, a motor, a central rotating shaft, conductive rings, a second housing rotatably fitted onto the conductive rings and the central rotating shaft, and brushes corresponding to the conductive rings and fixed to the inner wall of the second housing. The central rotating shaft rotates with an output shaft. A rotating probe is connected to the central rotating shaft, and its input and output ends are electrically connected to two of the conductive rings via wires located inside the central rotating shaft. These two conductive rings are designated as first conductive rings, and the brushes corresponding to the first conductive rings are designated as first brushes. A notch is provided on the first conductive rings, ensuring that at least one of the first conductive rings and the first brushes is always non-conductive. This invention eliminates the need for an encoder input interface from the eddy current meter, and the speed measurement signal and the detection signal from the eddy current probe are transmitted synchronously, significantly simplifying the on-site wiring and offering significant advantages.

Description

Technical Field

[0001] This invention belongs to the field of nuclear power testing equipment, and specifically relates to a rotating eddy current testing device, a rotation speed measurement method, and an eddy current testing method. Background Technology

[0002] Steam generators are crucial equipment in the primary loop system of nuclear power plants. During operation, heat transfer tubes can develop defects such as cracks, dents, and wear. Failure to detect these defects promptly and effectively can lead to emergency shutdowns due to heat transfer tube leaks. Regular non-destructive testing of heat transfer tubes to determine the type, location, and severity of degradation is essential for ensuring the safe and reliable operation of nuclear power plants. Eddy current testing is commonly used for in-service inspection of heat transfer tubes in nuclear power plants. Conventional Bobbin probes offer fast inspection speeds, low costs, and the ability to detect most defect types, making them widely used in pre-service and in-service inspections of heat transfer tubes. However, this type of probe has limitations. The circumferentially wound detection coil can only determine the axial location of heat transfer tube degradation, failing to provide information on the circumferential distribution of defects. Furthermore, it is prone to missing crack-like defects. To address these issues, rotating pancake coils (RPCs) are typically used to verify defects detected by the Bobbin probe. Common rotating probes consist of coils with different specifications and winding methods, such as intermediate frequency coils, high frequency coils, and cross coils, to ensure good sensitivity to various types of defects.

[0003] When performing eddy current testing on a heat transfer tube using a rotating probe, the rotating probe is fixed to the front end of a motor. The motor consists of a motor at the front end and a rigid nylon tube connected to the rear end of the motor. After the test begins, the rotating probe is driven by the motor at the front end of the motor and rotates inside the heat transfer tube. At the same time, the eddy current probe pusher clamps the nylon tube and propels the motor forward at a constant speed. The coil on the rotating probe moves forward in a spiral shape inside the heat transfer tube to complete the test.

[0004] To ensure the successful completion of the inspection, information such as rotation speed and number of rotations is required. This ensures that the eddy current data acquisition software can generate a three-dimensional C-scan image, and that the C-scan image can accurately reflect the location and distribution of defects.

[0005] Traditional speed measurement methods such as photoelectric encoders and Hall sensors require power supply and speed information output cables, and additional devices need to be added to the tail of the motor. This results in problems such as increased motor length, the need for an eddy current meter to provide a position encoder input interface, and complicated wiring for on-site inspection. Summary of the Invention

[0006] The purpose of this invention is to provide a rotating eddy current detection device that can obtain the rotational speed of the rotating probe with a simple wiring method for eddy current detection and analysis.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a rotating eddy current detection device, comprising:

[0008] Eddy current meter;

[0009] A drive unit includes a first housing and a motor mounted inside the housing, the motor having an output shaft;

[0010] A slip ring includes a central rotating shaft, a plurality of coaxial and mutually insulated conductive rings fixedly sleeved on the central rotating shaft, a second outer shell rotatably sleeved on the conductive rings and the central rotating shaft, and brushes corresponding one-to-one with the conductive rings and fixed to the inner sidewall of the second outer shell. The central rotating shaft rotates with the output shaft.

[0011] A rotating probe is connected to the central rotating shaft, and its input end and output end are respectively electrically connected to two of the conductive rings through wires provided in the central rotating shaft. The two conductive rings are the first conductive ring and the second conductive ring, and the brush corresponding to the first conductive ring is the first brush.

[0012] The first conductive ring has a notch that ensures that the first conductive ring and the first brush are not conductive at all times.

[0013] In an optimized configuration, the first and second outer shells are fixed relative to each other.

[0014] In the optimized configuration, the brush opposite the second conductive ring is the second brush. The eddy current meter includes an excitation source and a receiver. The excitation source is connected to the output end of the first brush via a wire. The first brush rests against the first conductive ring and always tends to move towards the first conductive ring. The first conductive ring and the second conductive ring are connected via a wire disposed within the central rotating shaft. The second brush rests against the second conductive ring and always tends to move towards the second conductive ring. The output end of the second brush is connected to the receiver.

[0015] In an optimized configuration, the drive unit further includes a nylon tube connected to the first housing, and the motor wires and the wires on the brush are housed within the nylon tube.

[0016] The present invention also provides a method for measuring rotational speed based on the above-mentioned rotating eddy current detection device, which includes the following steps:

[0017] a. The excitation source of the eddy current meter generates a sinusoidal signal;

[0018] b. The sinusoidal signal is transmitted sequentially through a wire, a first brush, a first conductive ring, a wire, a second conductive ring, a second brush, and a wire to the receiver of the eddy current meter;

[0019] c. When the first brush contacts the non-notched part on the first conductive ring, the signal received by the receiver is a sine wave output by the excitation source. After signal processing, the bar graph of the data acquisition software is a straight line. When the first brush contacts the notched part on the first conductive ring, the slip ring channel is no longer conductive, and the receiver no longer receives a sine wave signal. After data processing inside the eddy current meter, the bar graph of the data acquisition software is a square wave signal.

[0020] d. For each revolution of the central shaft of the slip ring, the rotating probe rotates synchronously by one revolution. The eddy current detection channel of the data acquisition software will generate the same square wave signal. By observing the frequency of the square wave signal output, the rotational speed of the rotating probe can be measured. By observing the number of times the square wave signal appears, the number of revolutions of the rotating probe can be measured. By observing whether the interval between the square wave signals is uniform, the uniformity of the rotating probe can be measured.

[0021] The present invention also provides an eddy current detection method based on the above-mentioned rotation speed measurement method, which includes obtaining the rotation speed of the rotating probe using the rotation speed measurement method, and then performing eddy current detection analysis based on the rotation speed of the rotating probe.

[0022] The optimized rotating probe rotates at a constant speed of 100 RPM-1000 RPM.

[0023] The beneficial effects of this invention are as follows: speed measurement is performed based on the principle of eddy current detection, eliminating the need for an encoder input interface from the eddy current meter. The speed measurement signal and the detection signal from the eddy current probe are transmitted synchronously, significantly simplifying the on-site wiring method and providing significant advantages. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the principle of a rotating eddy current detection device;

[0025] Figure 2 This is a schematic diagram of the slip ring structure;

[0026] Figure 3 This is a schematic diagram of the slip ring structure after the second housing has been removed;

[0027] Figure 4 This is a schematic diagram showing the connection between the slip ring, the rotary probe, and the output shaft.

[0028] Figure 5 This is a schematic diagram of the structure of the first slip ring and the first brush;

[0029] Figure 6 This is a schematic diagram of the structure of the second slip ring and the second brush;

[0030] Figure 7 This is a schematic diagram of the speed measurement signal from the rotating probe. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings:

[0032] like Figure 1 As shown, the rotating eddy current detection device includes: an eddy current meter 1, which includes an excitation source 11 and a receiver 12; a drive unit 2, which includes a nylon tube 21, a first housing 22, and a motor 23 installed inside the housing. The nylon tube 21 is connected to the first housing 22, and its length is typically several meters, with a certain degree of flexibility to ensure that the rotating probe 3 can be inserted into the heat transfer tube. An eddy current probe pusher is typically used to push the probe, ensuring that the rotating probe 3 moves forward at a constant speed. The motor 23 has an output shaft 231. Figure 2-6 As shown, the slip ring 24 includes a central rotating shaft 25, a plurality of coaxial and mutually insulated conductive rings 26 fixedly sleeved on the central rotating shaft 25, insulating washers 210 disposed on the central rotating shaft 25 and used to insulately separate the conductive rings 26, a second outer shell 27 rotatably sleeved on the conductive rings 26 and the central rotating shaft 25, and brushes 28 corresponding one-to-one with the conductive rings 26 and fixed to the inner wall of the second outer shell 27. The central rotating shaft 25 rotates with the output shaft 231; the rotating probe 3 rotates with the central rotating shaft 24. The shaft 25 is connected, and its input end and output end are respectively electrically connected to two conductive rings 26 through wires 29 provided in the central rotating shaft 25. The two conductive rings 26 are the first conductive ring 261 and the second conductive ring 262, and the brush 28 corresponding to the first conductive ring 261 is the first brush 281. The first conductive ring 261 has a notch 263 that makes the first conductive ring 261 and the first brush 281 have at least one non-conductive connection. In this embodiment, there is one notch 263.

[0033] The first outer casing 22 and the second outer casing 27 are fixedly connected. The brush 28 opposite the second conductive ring 262 is the second brush 282. The excitation source 11 is connected to the output end of the first brush 281 via a wire 29. The first brush 281 rests against the first conductive ring 261 and always tends to move towards the first conductive ring 261. The first conductive ring 261 and the second conductive ring 262 are connected via a wire 29 located within the central rotating shaft 25. The second brush 282 rests against the second conductive ring 262 and always tends to move towards the second conductive ring 262. The output end of the second brush 282 is connected to the receiver 12. The wires 29 of the motor 23 and the wires 29 on the brush 28 are housed within the nylon tube 21.

[0034] The rotational speed measurement method based on the above-mentioned rotating eddy current detection device includes the following steps:

[0035] a. The excitation source 11 of the eddy current meter 1 generates a sinusoidal signal;

[0036] b. The sinusoidal signal is transmitted sequentially through wire 29, first brush 281, first conductive ring 261, wire 29, second conductive ring 262, second brush 282, and wire 29 to the receiver 12 of the eddy current meter 1;

[0037] c. When the first brush 281 contacts the non-notched portion of the first conductive ring 261, the signal received by the receiver 12 is a sine wave output by the excitation source 11. After signal processing, the bar graph of the data acquisition software appears as a straight line. When the first brush 281 contacts the notched portion of the first conductive ring 261, the slip ring 24 channel is no longer conductive, and the receiver 12 no longer receives a sine wave signal. After data processing inside the eddy current meter 1, the bar graph of the data acquisition software appears as a square wave signal, such as... Figure 7 As shown;

[0038] d. For each revolution of the central shaft 25 of the slip ring 24, the rotating probe 3 rotates synchronously once. The eddy current detection channel of the data acquisition software will generate the same square wave signal. By observing the frequency of the square wave signal output, the rotation speed of the rotating probe 3 can be measured. By observing the number of times the square wave signal appears, the number of revolutions of the rotating probe 3 can be measured. By observing whether the interval between the square wave signals is uniform, the uniformity of the rotating probe 3 can be measured.

[0039] The eddy current detection method based on the above-mentioned rotation speed measurement method includes obtaining the rotation speed of the rotating probe 3 using the rotation speed measurement method, and then performing eddy current detection analysis based on the rotation speed of the rotating probe 3; the rotating probe 3 rotates at a uniform speed and its rotation speed is: 100RPM-1000RPM.

[0040] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A rotating eddy current detection device, comprising: an eddy current instrument; a driving part, comprising a first housing, a motor mounted in the first housing, the motor having an output shaft; a slip ring, comprising a central rotating shaft, a plurality of coaxial and mutually insulated conductive rings fixedly sleeved on the central rotating shaft, a second housing rotatably sleeved on the conductive rings and the central rotating shaft, and an electric brush corresponding to each of the conductive rings and fixed to the inner side wall of the second housing, the central rotating shaft rotating with the output shaft; a rotating probe connected to the central rotating shaft, and having an input end and an output end respectively electrically connected to two of the conductive rings through wires arranged in the central rotating shaft, the two conductive rings being a first conductive ring and a second conductive ring respectively, and the electric brush corresponding to the first conductive ring being a first electric brush; characterized in that the first conductive ring is provided with a gap allowing the first conductive ring and the first electric brush to be not conductive at least at one time, the electric brush opposite to the second conductive ring being a second electric brush, the eddy current instrument comprising an excitation source and a receiver, the excitation source being connected to the outgoing line end of the first electric brush through a wire, the first electric brush abutting against the first conductive ring and always having a tendency to move towards the first conductive ring, the first conductive ring being connected to the second conductive ring through a wire arranged in the central rotating shaft, the second electric brush abutting against the second conductive ring and always having a tendency to move towards the second conductive ring, and the outgoing line end of the second electric brush being connected to the receiver.

2. A rotational vortex flow detection device according to claim 1, characterised in that: The first housing and the second housing are fixedly arranged opposite to each other.

3. The rotational vortex flow detection device of claim 1, wherein: The driving part further comprises a nylon tube connected to the first housing, the wires of the motor and the wires of the electric brushes being accommodated in the nylon tube.

4. A method of measuring the rotational speed based on the rotational vortex flow detection device according to any one of claims 1 to 3, characterized by, It comprises the following steps: a. the excitation source of the eddy current instrument generates a sine wave signal; b. the sine wave signal is transmitted to the receiver of the eddy current instrument through wires, the first electric brush, the first conductive ring, wires, the second conductive ring, the second electric brush and wires in sequence; c. when the first electric brush contacts the non-gap part of the first conductive ring, the signal received by the receiver is the sine wave output by the excitation source, after signal processing, the bar graph of the data acquisition software shows a straight line, when the first electric brush contacts the gap part of the first conductive ring, the slip ring channel is no longer conductive, the receiver no longer receives the sine wave signal, after data processing inside the eddy current instrument, the bar graph of the data acquisition software shows a square wave signal; d. for each revolution of the central rotating shaft of the slip ring, the rotating probe rotates one revolution synchronously, the eddy current detection channel of the data acquisition software generates the same square wave signal, by observing the frequency of the square wave signal, the rotating speed of the rotating probe can be measured, by observing the number of times the square wave signal appears, the number of revolutions of the rotating probe can be measured, and by observing whether the intervals between the square wave signals are uniform, whether the rotating probe rotates at a constant speed can be measured.

5. An eddy current detection method based on the rotational speed measurement method of claim 4, characterized in that, It comprises obtaining the rotating speed of the rotating probe by using the rotating speed measurement method, and then performing eddy current detection analysis according to the rotating speed of the rotating probe.

6. The rotational speed measurement method according to claim 5, characterized in that: The rotating probe rotates at a constant speed, and the rotating speed is 100 RPM-1000 RPM.

Images