Pulsed eddy current testing device for steel double-jacketed pressure vessels

Abstract

The utility model relates to eddy current nondestructive testing technical field, concretely relates to a pulse eddy current detection device for steel double -layered jacket type pressure vessel, including scanning frame, the top of scanning frame is fixed with the handle, and the both ends of scanning frame are provided with fixed wheel group respectively, be provided with detection probe fixed support between two fixed wheel groups, and the end of detection probe fixed support is provided with detection probe casing, and the pulse eddy current detection probe of inverted '' V '' type is built -in in detection probe casing. The pulse eddy current detection device for steel double -layered jacket type pressure vessel of the utility model, through the magnetic field of inverted '' V '' type, can promote the detection sensitivity of inner tube local corrosion defect, and accurately identifies the corrosion thinning defect that appears in inner tube local.

Description

Technical Field

[0001] This utility model relates to the field of eddy current nondestructive testing, specifically to a pulsed eddy current testing device for steel double-layer jacketed pressure vessels. Background Technology

[0002] Steel jacketed pressure vessels are a type of special pressure vessel widely used in chemical equipment. These pressure vessels are typical multi-cavity containers, using a jacket to heat or cool the material inside the cylinder, thereby maintaining the optimal temperature of the inner cylinder. Therefore, they are widely used in the chemical and petroleum industries. The jacket is a partially or completely sealed steel structure on the outside of a standard pressure vessel, connected by flanges or welded to form a sealed space with the outer wall of the pressure vessel. Cooling or heating media are circulated through the jacket to cool or heat the material inside the pressure vessel. Under operating conditions, conventional non-destructive testing methods such as ultrasonic and radiographic testing are insufficient to detect corrosion thinning in the inner cylinder of jacketed pressure vessels. Therefore, the presence of potential safety hazards related to corrosion thinning in the inner cylinder is generally only detected through internal inspection during periodic inspections of jacketed pressure vessels. The Technical Regulations for Safety Supervision of Fixed Pressure Vessels in my country, TSG21-2016, stipulate that the regular inspection cycle for compliant metal pressure vessels is generally 3 to 6 years. However, due to the need for continuous production, enterprises often cannot choose to open the vessel for internal inspection. As a result, it is difficult to measure the wall thickness of the inner cylinder of the jacketed pressure vessel to assess whether there is corrosion thinning.

[0003] Pulsed eddy current testing (PDC) is a novel non-destructive testing technology that has been increasingly applied in recent years to the corrosion detection of coated pipelines and pressure vessels in the petrochemical industry. Because it uses a pulsed square wave as the excitation signal, it offers greater detection capability compared to conventional eddy current testing using a sine wave. However, current national and industry standards in China stipulate that PDC is suitable for metal protective layers with a thickness of no more than 1 mm, and it only has sufficient sensitivity for detecting large-volume corrosion thinning defects. The steel outer jacket of commonly used jacketed pressure vessels in the petrochemical industry typically has a thickness of 5-10 mm, far exceeding 1 mm. Furthermore, practical experience has shown that localized, small-volume corrosion thinning is a major factor causing leaks in jacketed pressure vessels. Therefore, detecting localized corrosion leaks in the inner cylinder of jacketed pressure vessels under in-use, non-opening conditions remains a challenging problem. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects and shortcomings of the prior art and provide a pulsed eddy current detection device for steel double-layer jacketed pressure vessels. This pulsed eddy current detection device can improve the detection sensitivity of local corrosion defects in the inner cylinder through an inverted "V" shaped magnetic field and accurately identify local corrosion thinning defects in the inner cylinder.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A pulsed eddy current detection device for a steel double-layer jacketed pressure vessel is characterized by comprising a scanning frame, a handle fixedly provided on the top of the scanning frame, and fixed wheel sets respectively provided at both ends of the scanning frame. A detection probe mounting bracket is provided between the two fixed wheel sets, and a detection probe housing is provided at the end of the detection probe mounting bracket; The detection probe housing contains an inverted "V" shaped pulse eddy current detection probe.

[0006] As a preferred embodiment, the pulsed eddy current detection probe includes an excitation coil frame, a receiving coil frame, an excitation coil, and a receiving coil; The excitation coil frame is inverted "V" shape, and two receiving coil frames are respectively set at the two ends of the excitation coil frame. The excitation coil is wound around the outside of the excitation coil frame, and the receiving coil is wound around the outside of the receiving coil frame.

[0007] As a preferred embodiment, the included angle between the two inclined sides of the excitation coil frame is 30°-75°.

[0008] As a preferred embodiment, the center-to-center distance between the two receiving coils is 70mm-100mm.

[0009] As a preferred embodiment, the excitation coil frame is made of 1J22 iron-cobalt-vanadium soft magnetic alloy material.

[0010] As a preferred embodiment, at least one of the fixed wheel assembly and the detection probe fixing bracket is movably mounted on the scanning frame.

[0011] As a preferred embodiment, the fixed wheel set can slide along the axial direction of the scanning frame; The pulsed eddy current detection device also includes a fixed wheel group locking component. An adjustment groove extending along the axis of the scanning frame is provided on the scanning frame. A fixed wheel group positioning hole is provided at the upper end of the fixed wheel group. The fixed wheel group locking component passes through the fixed wheel group positioning hole and locks with the adjustment groove.

[0012] As a preferred embodiment, the probe mounting bracket can slide along the axial direction of the scanning frame; The pulsed eddy current detection device also includes a detection probe fixing bracket locking component. An adjustment groove extending along the axis of the scanning frame is provided on the scanning frame. A detection probe fixing bracket positioning hole is provided at the upper end of the detection probe fixing bracket. The detection probe fixing bracket locking component passes through the detection probe fixing bracket positioning hole and locks with the adjustment groove.

[0013] As a preferred embodiment, the detection probe mounting bracket is connected to the detection probe housing via a connecting arm, and the receiving coil forms a 3-5mm gap with the surface of the steel double-layer jacketed pressure vessel.

[0014] As a preferred embodiment, the fixed wheel assembly includes a fixed wheel, an end cap, hex bolts, and a fixed wheel frame. The fixed wheel is detachably mounted on the fixed wheel frame by engaging the end cap with the hex bolts.

[0015] In summary, this utility model has the following advantages: 1. This utility model generates an inverted "V" shaped magnetic field by setting an inverted "V" shaped pulse eddy current detection probe, focusing the magnetic field and expanding the magnetic field coverage area, so that the eddy current distortion caused by the corrosion and thinning area of ​​the inner cylinder can be easily captured, thereby improving the detection sensitivity of local corrosion defects in the inner cylinder and accurately identifying corrosion and thinning defects that occur locally in the inner cylinder.

[0016] 2. This utility model focuses the magnetic field by setting the excitation coil frame in an inverted "V" shape with an included angle of 30°-75°. The magnetic field energy is concentrated and penetrates the outer jacket and interlayer, reaching the surface of the inner cylinder, thus achieving the effect of focusing the magnetic field penetration path. Furthermore, the excitation coil frame is made of 1J22 iron-cobalt-vanadium soft magnetic alloy material. 1J22 iron-cobalt-vanadium soft magnetic alloy is a high magnetic permeability material, which enhances the magnetic field penetration force. Therefore, it can detect localized small-volume corrosion with an inner cylinder area of ​​not less than 50 mm² and a wall thickness reduction of ≥20%.

[0017] 3. By setting up dual receiving coils and setting the center distance between the two receiving coils to 70mm-100mm, this utility model can enhance the contrast of defect signals, improve the identification accuracy of local small-volume corrosion, and effectively solve the problem of missed detection caused by unreasonable coil layout in the prior art.

[0018] 4. The fixed wheel assembly and detection probe fixing bracket of this utility model achieve the effect of quickly adapting to different cylinder curvatures by sliding along the adjustment groove and setting the locking part, which improves the stability of the scanning frame and the surface of the steel double-layer jacketed pressure vessel, and at the same time reduces the adjustment time of the pulse eddy current detection device.

[0019] 5. This utility model uses a connecting arm to maintain a 3-5mm gap between the receiving coil and the surface of the steel double-layer jacketed pressure vessel, thereby suppressing interference from the unevenness of the outer jacket and reducing the false alarm rate.

[0020] 6. With the PVC anti-slip wheel surface and wheel contact structure, the operator can push the handle with one hand to continuously scan, so that the pulse eddy current detector can receive signals in real time.

[0021] 7. This utility model achieves the effect of quickly replacing worn parts by setting up a modular assembly structure (hexagonal bolts + end caps) for fixing the wheel set, thereby reducing the maintenance cost of the pulse eddy current detection device.

[0022] 8. The scanning frame of this utility model is made of non-ferromagnetic TC4 titanium alloy, which can eliminate low-frequency electromagnetic interference, ensure the stability of signal acquisition, and avoid background noise caused by traditional iron brackets. Attached Figure Description

[0023] Figure 1 This is a front view of the pulse eddy current detection device for a steel double-layer jacketed pressure vessel according to the present invention. Figure 2 This is a schematic diagram of the structure of the pulsed eddy current detection probe of this utility model; Figure 3 This is a bottom view of the pulse eddy current detection device for a steel double-layer jacketed pressure vessel according to this utility model. Figure 4 This is a left view of the pulse eddy current detection device for a steel double-layer jacketed pressure vessel according to this utility model. Figure 5 This is a front view of the detection probe housing of this utility model; Figure 6 This is a top view of the detection probe housing of this utility model; Figure 7 This is a schematic diagram of the pulse eddy current detection device for steel double-layer jacketed pressure vessels according to this utility model.

[0024] Among them: 01: Pulse eddy current testing instrument, 02: Steel double-layer jacketed pressure vessel, 1: Scanning frame, 1-1: Handle, 1-2: Plastic sheath, 2: Fixed wheel frame, 2-1: Fixed wheel set, 2-2: End cover, 2-3: Hex bolt, 2-4: Fixed wheel frame, 3: Detection probe fixing bracket, 3-1: Connecting arm, 4: Detection probe housing, 4-1: Upper end cover of detection probe housing, 5: Excitation coil, 6: Receiving coil, 7: Signal receiving wire, 8: Signal transmitting wire. Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0026] A pulsed eddy current detection device for a steel double-jacketed pressure vessel includes a rectangular scanning frame 1, which is made of non-ferromagnetic TC4 titanium alloy material, and a handle 1-1 is fixed on the top. The gripping section of the handle 1-1 is covered with a plastic sheath 1-2.

[0027] The scanning frame 1 has fixed wheel sets 2 at both ends, and a detection probe fixing bracket 3 is set between the two fixed wheel sets 2. A detection probe housing 4 is set at the end of the detection probe fixing bracket 3. The fixed wheel sets 2, the detection probe fixing bracket 3, and the detection probe housing 4 are all made of polyoxymethylene (POM) or polyamide (PA) material, and the length-to-width ratio of the detection probe housing 4 is 7:5:4.

[0028] The detection probe housing 4 houses an inverted "V"-shaped pulsed eddy current detection probe, which includes an excitation coil frame, a receiving coil frame, an excitation coil 5, and a receiving coil 6.

[0029] Specifically, the excitation coil frame is inverted "V" shape, with an included angle of 30°-75° between the two hypotenuses, and is made of 1J22 iron-cobalt-vanadium soft magnetic alloy material; the two receiving coil frames are respectively set at the two ends of the excitation coil frame, and the receiving coil frame is circular and made of polyamide engineering plastic.

[0030] The upper end face of the receiving coil frame is fixed to the end face of the excitation coil frame by hot-melt welding, and the lower end face is fixed to the bottom of the detection probe housing 4 by hot-melt welding. The excitation coil 5 is wound around the outside of the inverted "V"-shaped excitation coil frame, and copper wire with a diameter of 1.0mm-2.1mm and 200-300 turns is wound around its exterior. The receiving coil 6 is wound around the outside of a circular receiving coil frame, and copper wire with a diameter of 0.41mm-0.5mm and 350-500 turns is wound around its exterior. The center-to-center distance between the two receiving coils 6 is 70mm-100mm.

[0031] The excitation coil 5 and the receiving coil 6 are connected to the pulse eddy current testing instrument 01 (model NCHGPEC-02+) via the signal transmitting wire 8 and the signal receiving wire 7, respectively. The detection probe housing 4 includes an upper cover 4-1, on which two through holes are provided for the signal transmitting wire 8 and the signal receiving wire 7 to pass through and connect to the corresponding ports of the pulse eddy current testing instrument 01.

[0032] Furthermore, at least one of the fixed wheel assembly 2 and the detection probe fixing bracket 3 is movably mounted on the scanning frame 1.

[0033] In this embodiment, the fixed wheel assembly 2 and the detection probe fixing bracket 3 are both movably mounted on the scanning frame 1, and the fixed wheel assembly 2 and the detection probe fixing bracket 3 can slide freely along the axial direction of the scanning frame 1.

[0034] The scanning frame 1 has symmetrical adjustment grooves machined on both sides using wire cutting. The length of the adjustment grooves is 100mm-150mm, and the maximum width is 5mm-10mm. The pulse eddy current detection device also includes a fixed wheel assembly locking component and a detection probe fixing bracket locking component. The upper end of the fixed wheel assembly 2 has a fixed wheel assembly positioning hole, through which the fixed wheel assembly locking component passes and locks into the adjustment groove. The upper end of the detection probe fixing bracket has a detection probe fixing bracket positioning hole, through which the detection probe fixing bracket locking component passes and locks into the adjustment groove. Loosening the fixed wheel assembly locking component and the detection probe fixing bracket locking component allows for stepless adjustment of the positions of the fixed wheel assembly 2 and the detection probe fixing bracket 3 within the adjustment groove range. After adjustment, tightening secures them, achieving rapid and accurate positioning.

[0035] The detection probe fixing bracket 3 is connected to the detection probe housing 4 via the connecting arm 3-1, and the receiving coil 6 forms a 3-5mm gap with the surface of the steel double-layer jacketed pressure vessel.

[0036] The fixed wheel assembly 2 includes a fixed wheel 2-1, an end cap 2-2, hexagonal bolts 2-3, and a fixed wheel frame 2-4. The fixed wheel 2-1 is detachably mounted on the fixed wheel frame 2-4 via the hexagonal bolts 2-3 and the end cap 2-2. The fixed wheel 2-1 is provided with a PVC anti-slip pad, which can effectively increase the friction between the pulse eddy current detection device and the outer jacket of the steel double-jacketed pressure vessel.

[0037] The most threatening safety hazard during the service of the steel double-jacketed pressure vessel 02 is corrosion thinning and penetration of the inner lining. This invention enables rapid inspection of corrosion thinning defects in the inner lining of the in-service steel double-jacketed pressure vessel 02 without opening the vessel.

[0038] Before use, the outer covering of the steel double-jacketed pressure vessel 02 needs to be removed. After determining the scope to be inspected, the pulse eddy current detection device is placed on the metal surface of the outer jacket of the steel double-jacketed pressure vessel 02. The device is driven by the part of the handle 1-1 with the plastic sheath 1-2, and data is collected by rolling scan. It should be noted that the stepping speed of the pulse eddy current detection device should be controlled at 250 mm / s, and the detection length of each scan should be controlled within 2 m.

[0039] This utility model can rapidly identify and scan corrosion defects in the inner cylinder of a steel double-layer jacketed pressure vessel 02 under the following conditions: the maximum nominal wall thickness of the outer jacket is 10 mm, the maximum distance between the inner and outer cylinders is 12 mm, the maximum wall thickness of the inner cylinder is 12 mm when it is made of ferromagnetic material and 10 mm when it is made of non-ferromagnetic material. It can detect localized small-volume corrosion with an inner cylinder area of ​​not less than 50 mm² and a wall thickness reduction of ≥20%.

[0040] In summary, this invention employs a specific inverted "V"-shaped 1J22 iron-cobalt-vanadium soft magnetic alloy excitation coil 5, which has stronger magnetic field penetration compared to traditional gate-shaped, circular, rectangular, and elliptical coil probes. Experimental verification shows that it has better detection sensitivity for local corrosion defects in the inner cylinder of steel double-layer jacketed pressure vessels. At the same time, the dual-channel probe mode effectively improves detection efficiency.

[0041] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A pulsed eddy current detection device for a steel double-jacketed pressure vessel, characterized in that: Includes a scanning frame (1), with a handle (1-1) fixed on the top of the scanning frame (1), and fixed wheel sets (2) respectively at both ends of the scanning frame (1). A detection probe fixing bracket (3) is provided between the two fixed wheel sets (2), and a detection probe housing (4) is provided at the end of the detection probe fixing bracket (3). The detection probe housing (4) contains an inverted "V" shaped pulse eddy current detection probe.

2. The pulse eddy current detection device for a steel double-jacketed pressure vessel according to claim 1, characterized in that: The pulsed eddy current detection probe includes an excitation coil frame, a receiving coil frame, an excitation coil (5), and a receiving coil (6). The excitation coil frame is inverted "V" shape, and the two receiving coil frames are respectively set at the two ends of the excitation coil frame. The excitation coil (5) is wound around the outside of the excitation coil frame, and the receiving coil (6) is wound around the outside of the receiving coil frame.

3. The pulse eddy current detection device for a steel double-jacketed pressure vessel according to claim 2, characterized in that: The included angle between the two hypotenuses of the excitation coil frame is 30°-75°.

4. The pulse eddy current detection device for a steel double-jacketed pressure vessel according to claim 2, characterized in that: The center-to-center distance between the two receiving coils (6) is 70mm-100mm.

5. A pulsed eddy current detection device for a steel double-jacketed pressure vessel according to claim 2, characterized in that: The excitation coil frame is made of 1J22 iron-cobalt-vanadium soft magnetic alloy material.

6. The pulse eddy current detection device for a steel double-jacketed pressure vessel according to claim 1, characterized in that: At least one of the fixed wheel assembly (2) and the detection probe fixing bracket (3) is movably mounted on the scanning frame (1).

7. The pulse eddy current detection device for a steel double-jacketed pressure vessel according to claim 6, characterized in that: The fixed wheel assembly (2) can slide along the axis of the scanning frame (1); The pulse eddy current detection device also includes a fixed wheel group locking component. An adjustment groove extending along the axis of the scanning frame (1) is provided on the scanning frame (1). A fixed wheel group positioning hole is provided at the upper end of the fixed wheel group (2). The fixed wheel group locking component passes through the fixed wheel group positioning hole and locks with the adjustment groove.

8. A pulsed eddy current detection device for a steel double-jacketed pressure vessel according to claim 6, characterized in that: The detection probe fixing bracket (3) can slide along the axis of the scanning frame (1); The pulse eddy current detection device also includes a detection probe fixing bracket locking component. An adjustment groove extending along the axis of the scanning frame (1) is provided on the scanning frame (1). A detection probe fixing bracket positioning hole is provided at the upper end of the detection probe fixing bracket. The detection probe fixing bracket locking component passes through the detection probe fixing bracket positioning hole and locks with the adjustment groove.

9. A pulsed eddy current detection device for a steel double-jacketed pressure vessel according to claim 2, characterized in that: The detection probe fixing bracket (3) is connected to the detection probe housing (4) through the connecting arm (3-1), and the receiving coil (6) forms a gap of 3-5mm with the surface of the steel double-layer jacketed pressure vessel.

10. A pulsed eddy current detection device for a steel double-jacketed pressure vessel according to claim 1, characterized in that: The fixed wheel assembly (2) includes a fixed wheel (2-1), an end cap (2-2), a hex bolt (2-3), and a fixed wheel frame (2-4). The fixed wheel (2-1) is detachably mounted on the fixed wheel frame (2-4) by the hex bolt (2-3) and the end cap (2-2).

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