A self-rotating eddy current detection probe

Abstract

The present invention discloses a self-rotating eddy current detection probe, including a probe connector, an extended cable assembly, a slip ring protective shell, a signal transmission slip ring, a probe frame and a detection coil, wherein the probe connector is connected to the slip ring protective shell through the extended cable assembly, a signal transmission slip ring is mounted inside the slip ring protective shell, the signal transmission slip ring is connected to a probe frame arranged outside the slip ring protective shell, and a detection coil is arranged on the probe frame. The beneficial effects of the present invention are: the external overall structure of the coil frame of the present invention adopts a contoured design, and the coil part adopts an elliptical design to ensure the passability of the probe in the spiral flat tube; the present invention adopts a signal transmission slip ring design to avoid cable entanglement and realize the smooth transmission of eddy current signals; the present invention does not need to rely on external force, and the eddy current probe can rotate in the spiral flat tube to realize the eddy current signal collection of the spiral flat tube.

Description

Technical Field

[0001] The invention belongs to a detection probe, and in particular relates to a self-rotating eddy current detection probe. Background Art

[0002] The spiral flat tube is also called twisted tube. Its unique structural design makes the shell fluid velocity and direction change periodically. The fluid in the shell and tube is in a spiral motion state at the same time, which promotes the enhancement of turbulence. The heat transfer efficiency of the spiral flat tube heat exchanger is 40% higher than that of the ordinary heat exchanger, while the pressure drop is almost the same. Since 1984, thousands of spiral flat tube heat exchangers have been manufactured and sold all over the world, mainly used in gas-gas, liquid-liquid, liquid-gas heat exchange processes, covering many industries such as chemistry, petroleum, food, papermaking, electricity, metallurgy, mining and urban heating.

[0003] The spiral flat tube is formed through two manufacturing processes, namely "compression deviation" and "twisting". Any cross section of the heat exchange section of the tube is elliptical. When assembled into a heat exchanger, it can be a mixed tube bundle or a pure spiral flat tube bundle. It is precisely this spiral flat structural design that limits the detection methods for this type of spiral flat tube, and the detection sensitivity is not high. At present, the non-destructive testing of spiral flat tubes is mainly carried out at home and abroad through helium leak detection, but the helium leak detection method can only detect perforation defects and cannot predict the quality of spiral flat tubes in advance. Summary of the invention

[0004] The object of the present invention is to provide a self-rotating eddy current detection probe, which can drive the front elliptical coil to perform spiral scanning in the spiral flat tube without the need for external force, thereby completing the eddy current detection of the spiral flat tube.

[0005] The technical solution of the present invention is as follows: a self-rotating eddy current detection probe, comprising a probe connector, an extended cable assembly, a slip ring protective shell, a signal transmission slip ring, a probe frame and a detection coil, wherein the probe connector is connected to the slip ring protective shell through the extended cable assembly, a signal transmission slip ring is mounted inside the slip ring protective shell, the signal transmission slip ring is connected to a probe frame arranged outside the slip ring protective shell, and a detection coil is arranged on the probe frame.

[0006] The probe connector is connected to the extension cable assembly by welding.

[0007] The extension cable assembly is protected by a plastic sleeve on the outside, the eddy current signal transmission cable and the anti-pull-off wire rope pass through the plastic sleeve, and the plastic sleeve on the outside of the extension cable assembly is connected to the slip ring protective shell by glue injection.

[0008] The signal transmission slip ring is placed inside a slip ring protection shell, and the slip ring protection shell is made of stainless steel.

[0009] The signal transmission slip ring comprises an outer slip ring, a signal input contact ring, an inner slip ring, and a signal receiving spring sheet. A signal input contact ring is distributed at a certain distance in the axial direction of the inner slip ring, and there are four input contact rings in total. The signal input contact ring is embedded in the inner slip ring. A signal receiving spring sheet is distributed at a certain distance in the axial direction of the outer slip ring, and there are four input contact rings in total. One side of the signal receiving spring sheet is embedded in the outer slip ring, and the other side is overlapped with the signal input contact ring. Each signal receiving spring sheet overlaps a signal input contact ring.

[0010] The eddy current signal transmission cable inside the extended cable assembly is connected to the signal receiving spring sheet of the signal transmission slip ring, and the anti-pull-off steel wire rope inside the extended cable assembly is welded to the slip ring protective shell.

[0011] One end of the probe bone is a cone, and the probe skeleton is made of nylon material, and its appearance is similar to the internal structure of the spiral flat tube.

[0012] A hole is left in the probe frame for leading out four wires of the detection coil and respectively connected to four signal input contact rings of the left inner slip ring.

[0013] Two elliptical grooves are left at the front end of the probe skeleton.

[0014] The detection coil is composed of an exciting winding and a receiving winding, which are respectively located in two elliptical grooves at the front end of the probe frame.

[0015] The beneficial effects of the present invention are:

[0016] (1) The overall external structure of the coil skeleton of the present invention adopts a contoured design, and the coil part adopts an elliptical design to ensure the passability of the probe in the spiral flat tube;

[0017] (2) The present invention adopts a signal transmission slip ring design to avoid cable entanglement and achieve smooth transmission of eddy current signals;

[0018] (3) The eddy current probe of the present invention can rotate in the spiral flat tube without the help of external force, thereby collecting eddy current signals of the spiral flat tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of a self-rotating eddy current detection probe provided by the present invention;

[0020] Figure 2 An axial cross-sectional view of a signal transmission slip ring of a self-rotating eddy current detection probe provided by the present invention;

[0021] Figure 3 A cross-sectional view in the circumferential direction of a signal transmission slip ring of a self-rotating eddy current detection probe provided by the present invention;

[0022] Figure 4 This is a working diagram of a signal transmission slip ring detection of a self-rotating eddy current detection probe provided by the present invention.

[0023] In the figure, 1 is a probe connector, 2 is an extension cable assembly, 3 is a slip ring protective shell, 4 is a signal transmission slip ring, 5 is a probe frame, 6 is a detection coil, 41 is an outer slip ring, 42 is a signal input contact ring, 43 is an inner slip ring, 44 is a signal receiving spring sheet, 7 is a spiral flat tube, and 8 is a detection probe. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] The purpose of the invention is to provide a special self-rotating eddy current detection probe for eddy current detection of spiral flat tubes. The probe is an inner-penetrating eddy current probe and can implement eddy current detection from the inside of the spiral flat tube.

[0026] like Figure 1 As shown, a self-rotating eddy current detection probe includes six parts: a probe connector 1, an extension cable assembly 2, a slip ring protection shell 3, a signal transmission slip ring 4, a probe frame 5, and a detection coil 6.

[0027] Among them, the probe connector 1 is connected to the slip ring protective shell 3 through an extended cable assembly 2. The slip ring protective shell 3 is a cylindrical hollow structure, in which a signal transmission slip ring 4 is installed. The signal transmission slip ring 4 is connected to a probe frame 5 arranged outside the slip ring protective shell 3, and a detection coil 6 is arranged on the probe frame 5.

[0028] The probe connector 1 can be matched with a suitable type of connector according to the panel of the eddy current detector, and is connected to the extension cable assembly 2 by welding. The extension cable assembly 2 is protected by a plastic sleeve, and the eddy current signal transmission cable and the anti-pull-off wire rope pass through the plastic sleeve. The plastic sleeve on the outside of the extension cable assembly 2 is connected to the slip ring protective shell 3 on the right side by glue filling, and the eddy current signal transmission cable inside the extension cable assembly 2 is connected to the signal receiving spring sheet 44 of the signal transmission slip ring 4. The anti-pull-off wire rope inside the extension cable assembly 2 is welded to the left side of the slip ring protective shell 3 to ensure that when the signal transmission slip ring 4 and the probe skeleton 5 are accidentally broken, they can also be retracted outside the spiral flat tube.

[0029] The signal transmission slip ring 4 is placed inside the slip ring protective shell 3, which is usually made of stainless steel. When the slip ring protective shell 3 passes through the spiral flat tube, it can effectively protect the signal transmission slip ring 4 from damage, and also plays a role in waterproofing and shielding interference signals. The outer diameter of the slip ring protective shell 3 should be smaller than the minor axis length of the elliptical cross section of the spiral flat tube to ensure that it passes smoothly inside the spiral flat tube. The inner slip ring 43 of the signal transmission slip ring 4 is connected to the probe frame 5 on the left side through a rigid structure.

[0030] The signal transmission slip ring 4 is one of the core components of the present invention. The signal transmission slip ring 4 includes an outer slip ring 41, a signal input contact ring 42, an inner slip ring 43, and a signal receiving spring sheet 44. A signal input contact ring 42 is distributed at a certain distance in the axial direction of the inner slip ring 43, and there are four input contact rings 42 in total. The signal input contact ring 42 is embedded in the inner slip ring 43 and distributed 360° in the circumferential direction. A signal receiving spring sheet 44 is distributed at a certain distance in the axial direction of the outer slip ring 41, and there are four input contact rings 42 in total. One side of the signal receiving spring sheet 44 is embedded in the outer slip ring 41, and the other side overlaps with the signal input contact ring 42. Each signal receiving spring sheet 44 overlaps a signal input contact ring 42. When the probe skeleton 5 drives the inner slip ring 43 to rotate, since the signal receiving spring sheet 44 and the signal input contact ring 42 always maintain a contact state, eddy current signal transmission is realized.

[0031] The left side of the probe skeleton 5 is connected to the inner slip ring 43, and the right end of the probe skeleton 5 adopts a cone design. The probe skeleton 5 is made of nylon material, and its appearance should be consistent with the internal structure of the spiral flat tube. A hole is left in the probe skeleton 5 to lead out the four wires of the detection coil 6, and they are respectively connected to the four signal input contact rings 42 of the left inner slip ring 43. In order to ensure sufficient detection sensitivity, its filling factor should be greater than or equal to 80%, that is, (outer diameter of the detection coil 6 / inner diameter of the spiral flat tube) 2≥80%. Two elliptical grooves are left at the front end of the probe skeleton 5. The width, depth and spacing of the elliptical grooves are all 1.5mm. The enameled wire of appropriate size is selected to wind the detection coil 6. The detection coil 6 consists of an excitation winding and a receiving winding, which are respectively located in the two elliptical grooves at the front end of the probe skeleton 5.

[0032] The use process of the present invention is as follows:

[0033] The self-rotating eddy current detection probe works as follows Figure 4As shown, when the self-rotating eddy current detection probe 8 moves forward or backward in the spiral flat tube, since the appearance of the front eddy current detection probe is similar to the internal structure of the spiral flat tube 7, the front eddy current detection probe part will rotate in the spiral flat tube 7, and the inner slip ring 43 of the transmission slip ring 5 will be driven to rotate together during the rotation. At this time, the input contact ring 42 of the signal of the inner slip ring 43 and the signal receiving spring piece 44 of the outer slip ring 41 always maintain a contact state, so that the eddy current signal can be smoothly transmitted, thereby realizing the eddy current detection of the spiral flat tube 7 by the self-rotating eddy current detection probe 8.

[0034] The working principle of the self-rotating eddy current detection probe is as follows: when the exciting winding of the detection coil 6 is energized, eddy currents will be induced in the spiral flat tube 7, and the receiving winding in the detection coil 6 will be affected by the energized exciting winding. The induced current in the receiving winding and the eddy currents at each point in the spiral flat tube 7 will form their own magnetic field, which in turn will produce electromagnetic induction on the exciting winding. The change of current in the exciting winding will affect the change of eddy current in the spiral flat tube 7 and the change of current in the receiving winding. This will continue to reach a stable state. If a defect occurs in the spiral flat tube 7, the original stable state will be destroyed, and the defect information can be obtained from the output signal of the receiving winding.

Claims

1. A self-rotating eddy current detection probe, characterized in that: It includes a probe connector, an extended cable assembly, a slip ring protective shell, a signal transmission slip ring, a probe frame and a detection coil. The probe connector is connected to the slip ring protective shell through the extended cable assembly. The slip ring protective shell is provided with a signal transmission slip ring. The signal transmission slip ring is connected to the probe frame provided outside the slip ring protective shell. The probe frame is provided with a detection coil. The extension cable assembly is protected by a plastic sleeve on the outside, the eddy current signal transmission cable and the anti-pull-off wire rope pass through the plastic sleeve, and the plastic sleeve on the outside of the extension cable assembly is connected to the slip ring protective shell by glue filling; The signal transmission slip ring is placed inside the slip ring protective shell, and the slip ring protective shell is made of stainless steel; The signal transmission slip ring comprises an outer slip ring, a signal input contact ring, an inner slip ring, and a signal receiving spring sheet. A signal input contact ring is distributed at a certain distance in the axial direction of the inner slip ring, and there are four input contact rings in total. The signal input contact ring is embedded in the inner slip ring. A signal receiving spring sheet is distributed at a certain distance in the axial direction of the outer slip ring. One side of the signal receiving spring sheet is embedded in the outer slip ring, and the other side overlaps with the signal input contact ring. Each signal receiving spring sheet overlaps with a signal input contact ring. The eddy current signal transmission cable inside the extension cable assembly is connected to the signal receiving spring sheet of the signal transmission slip ring, and the anti-pull-off steel wire rope inside the extension cable assembly is welded to the slip ring protective shell; One end of the probe frame is a cone, and the probe frame is made of nylon material, and its appearance is similar to the internal structure of the spiral flat tube; A hole is left in the probe frame for leading out four wires of the detection coil and respectively connected to four signal input contact rings of the left inner slip ring.

2. A self-rotating eddy current detection probe as claimed in claim 1, characterized in that: The probe connector is connected to the extension cable assembly by welding.

3. A self-rotating eddy current detection probe as claimed in claim 1, characterized in that: Two elliptical grooves are left at the front end of the probe skeleton.

4. A self-rotating eddy current detection probe as claimed in claim 1, characterized in that: The detection coil is composed of an exciting winding and a receiving winding, which are respectively located in two elliptical grooves at the front end of the probe frame.

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