CN111307929A

CN111307929A - Metal pipeline device of detecting a flaw based on low frequency magnetic leakage

Info

Publication number: CN111307929A
Application number: CN201811512955.XA
Authority: CN
Inventors: 沈常宇; 陈晓彬
Original assignee: China Jiliang University
Current assignee: China Jiliang University
Priority date: 2018-12-11
Filing date: 2018-12-11
Publication date: 2020-06-19

Abstract

The invention relates to a metal pipeline flaw detection device based on low-frequency magnetic leakage, which is characterized in that a signal acquisition and processing system is formed by an AH3503 type Hall linear circuit and an amplifying circuit based on an (op07, op37) amplifier; the flexible tire mounting structure forms a device multi-environment adaptive system; a frame system of 120 x 68 x 210mm in size connecting and fixing the components; a3 steel is made, and a magnetic yoke with the inner and outer radiuses of 280-degree circular arc of 95 and 125mm and two exciting coils with 300 turns respectively form a signal generating system; the nickel sheet and the groove form an interference magnetic field isolation layer; the signal line is a signal output system. The remote control system includes a power supply and a 27mHZ four-way remote control pad to enable remote operation of the device. The moving device is operated by a transmitting plate remote controller, a Hall circuit automatically scans and collects magnetic field signals generated when the coil and the magnetic yoke move on the metal surface, and the magnetic field signals are amplified by an amplifier and then are compared with standard non-damage signals.

Description

Metal pipeline device of detecting a flaw based on low frequency magnetic leakage

Technical Field

The invention relates to a metal detection device based on low-frequency magnetic leakage, in particular to a low-frequency magnetic leakage metal pipeline flaw detection device.

Background

At present, pipelines for conveying liquid with high temperature, high pressure and strong corrosivity for a long time are mostly made of metal, once problems occur in the pipelines, disastrous accidents such as serious environmental pollution, fire disasters, explosions and the like are often caused due to the fact that the pipelines are exposed to a complex environment for a long time to operate, therefore, regular in-service state detection of the pipelines is very important, and meanwhile, the advanced and convenient nondestructive inspection technology is very necessary by considering factors such as cost, operation feasibility and field environment adaptability. Common nondestructive testing techniques include ultrasonic testing, radiation testing, magnetic flux leakage testing, eddy current testing, and the like. The ultrasonic detection is easy to interfere, the requirement on an object to be detected is high, and the requirement on a tester is high; the ray detection cost is too high, and the method is not sensitive to defects such as cracks; the low-frequency magnetic leakage detection is an electromagnetic nondestructive detection method, does not need to be in contact with the surface of a detected workpiece, and has higher detection sensitivity on corrosive damage. The low-frequency magnetic leakage detection technology starts from 1950, excitation frequency is usually 1KHz-500KHz, and is influenced by skin effect, penetration depth of magnetic leakage detection is greatly limited, and therefore the magnetic leakage detection is commonly used for metal surface and near surface detection. The low-frequency magnetic leakage overcomes the influence of skin effect by reducing frequency, effectively improves the detection depth by more than 30 times, has higher detection speed on various damages, can obtain satisfactory detection effects on the surface, the near surface, internal cracks, corrosion and the like of a ferromagnetic material, has simple structure, easy realization, low cost and simple operation, greatly improves the detection efficiency and reduces the workload because the change of magnetism is easy for non-contact measurement and online real-time detection and a magnetic field signal is not influenced by the surface pollution state of the detected material, and the surface of the detected material does not need to be cleaned when the detection is carried out, can realize full-automatic detection, and is very suitable for quality detection and production process control on a production line.

The low-frequency magnetic leakage detection device widely applied at present needs a large magnetic core, the magnetic field is greatly influenced by the defects of the device, the low-frequency magnetic leakage detection device cannot be well adapted to the transformation work of various environments, and the low-frequency magnetic leakage detection device also has large promotion and development space.

Disclosure of Invention

To solve the above technical problems, the present invention aims to: the metal pipeline flaw detection device is convenient, accurate and high in automation degree.

The technical scheme of the invention is as follows: a metal pipeline device of detecting a flaw based on low frequency magnetic leakage, it includes: (1) the device comprises a signal acquisition and processing system, (2) a multi-environment adaptation system, (3) a frame system for connecting and fixing all parts, (4) a signal generation system, (5) an interference magnetic field isolation layer, (6) a signal output system and (7) a remote control system. The signal acquisition and processing system (1) comprises an AH3503 type Hall linear circuit group (101) for acquiring signals and a signal amplification module (102), wherein an amplification circuit based on (op07, op37) amplifiers is adopted; (2) the device multi-environment adaptation system is provided with a flat ground tire using module (201) and a pipeline tire using module (202) with the curvature radius of 20mm, the flat ground tire using module is connected with a protrusion of a frame system (3) connected with and fixed to each part through a groove of the module and is fixed through two m2 screws, and the lifting height of 5mm of an AH3503 type Hall linear circuit group (101) is guaranteed; two excitation coils (402) are adopted, 300 turns of the two excitation coils are fixed on two sides of the magnetic yoke (401), the two excitation coils are placed in a groove of a frame system (3) for connecting and fixing all parts, and then glue is filled to fix the two excitation coils; the size of the frame system (3) connecting and fixing the components is 120mm 68mm 210 mm; the interference magnetic field isolation layer (5) is a nickel sheet fixed in a groove of the frame system (3) which is connected with and fixes each component and is used for covering the signal acquisition processing system (1); the signal output system (6) outputs a signal amplified by the amplifying circuit (102) of the signal amplifying module based on (op07, op37) amplifier, and the signal output system is composed of signal lines. The remote control system (7) comprises a power supply (701) and a four-way remote control board (702) with the frequency of 27mHZ, so that the device can be remotely controlled under the condition of sufficient power supply, and the flexibility is increased.

The invention has the beneficial effects that:

the device can stabilize the optimal lift-off height, and the measured signal is more accurate;

the arc-shaped magnetic core and the double coils of the device can amplify the magnetic field effect and enlarge the experimental phenomenon;

the tyre design of the device greatly reduces the loss of movement on the arc surface and increases the efficiency;

the device has high automation degree, integrates automatic scanning, checking and calibrating, and comparison and analysis, and reduces the operation difficulty and pressure of personnel;

description of the drawings:

FIG. 1 is a schematic diagram of a whole vehicle architecture of a metal pipeline flaw detection device based on low-frequency magnetic flux leakage;

FIG. 2 is a schematic diagram of components of a fixed AH3503 type Hall linear circuit and a signal amplification module of the metal pipeline flaw detection device based on low-frequency magnetic leakage;

FIG. 3 is a schematic view of a flat plate tire holder of a metal pipeline flaw detection device based on low frequency magnetic flux leakage;

FIG. 4 is a schematic view of a tire fixing seat for a curved pipeline of a metal pipeline flaw detection device based on low-frequency magnetic flux leakage;

FIG. 5 is a view showing the overall containment configuration of a metal pipeline inspection device based on low frequency leakage flux;

FIG. 6 is a schematic diagram of a magnetic core and a coil fixing case sleeved thereon of a metal pipeline flaw detection device based on low-frequency leakage flux;

a specific embodiment;

practical embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

Fig. 1 shows that a metal pipeline inspection device based on low frequency leakage is whole to be constituteed, and it includes: (1) the device comprises a signal acquisition and processing system, (2) a multi-environment adaptation system, (3) a frame system for connecting and fixing all parts, (4) a signal generation system, (5) an interference magnetic field isolation layer and (6) a signal output system.

Fig. 2 is a schematic diagram of a signal acquisition and processing system of a metal pipeline flaw detection device based on low-frequency magnetic leakage, wherein (101) an AH3503 type hall linear circuit collects signals generated by magnetic induction line cutting while the device moves, and the signals are transmitted to (102) an amplifying circuit based on an (op07, op37) amplifier through a signal line, amplified and then output through (6) a signal output system to analyze and compare.

Fig. 3 and 4 are schematic diagrams of a tire fixing seat for a panel of a metal pipeline flaw detection device and a tire fixing seat for a curved pipeline based on low-frequency magnetic leakage, a special bottom structure enables the device to work on a planar metal plate and also work on the curved metal pipeline, and the detachable fixing seat enables the device to adapt to variable working environments.

Fig. 5 shows a general assembly shell structure of a tire of a metal pipeline flaw detection device based on low-frequency magnetic flux leakage, which tightly connects the components of the device together to form a whole, and particularly notes that a reserved position between (4) a signal generation system and (1) a signal acquisition and processing system is used for placing a nickel sheet as a magnetic field isolation layer for (5) an interference magnetic field isolation layer, so as to avoid the influence of interference signals of a magnetic yoke.

Fig. 6 is a schematic diagram of a magnetic core and a coil fixing shell sleeved on the magnetic core of the metal pipeline flaw detection device based on low-frequency magnetic leakage, wherein 300 turns of excitation coils on two sides generate excitation signals to generate electromagnetic fields, the electromagnetic fields and the magnetic yokes act on a metal near surface together, and magnetic field signals continuously generated in the moving process of the device are processed and transmitted by a (101) AH3503 type hall linear circuit and a (102) amplifying circuit based on an (op07, op37) amplifier to be analyzed.

Claims

1. A metal pipeline flaw detection device based on low-frequency magnetic leakage comprises a signal acquisition and processing system (1), a multi-environment adaptation system (2), a frame system (3) for connecting and fixing all parts, a signal generation system (4), an interference magnetic field isolation layer (5), a signal output system (6) and a remote control system (7); the method is characterized in that: the signal acquisition and processing system (1) comprises a DH251 Hall element array group (101) for acquiring signals and a signal amplification module (102), wherein the signal amplification module (102) adopts an M13720 amplifier; the device multi-environment adaptation system (2) comprises a flat ground tire using module (201) and a pipeline tire using module (202), wherein the curvature radius of the pipeline tire using module (202) is 20mm, a protrusion of a frame system (3) for connecting and fixing all parts is connected with a groove of the device multi-environment adaptation system (2) and is fixed through two m2 screws, and the lift-off height of 5mm of a DH251 Hall element array group (101) is ensured; two excitation coils (402) are adopted, the number of the windings is 300, the windings are fixed on two sides of the magnet yoke (401), the windings are placed in grooves of a frame system (3) for connecting and fixing all parts, and then glue is poured to fix the windings; the size of the frame system (3) connecting and fixing the components is 120mm 68mm 210 mm; the interference magnetic field isolation layer (5) is made of nickel sheets, and the interference magnetic field isolation layer (5) is fixed in a groove of a frame system (3) for connecting and fixing all the components and is used for covering the signal acquisition and processing system (1); the signal output system (6) outputs the signal amplified by the signal amplification module M13720 amplifier (102); the remote control system (7) comprises a power supply (701) and a 27mHZ frequency four-way remote control board (702), the device can be remotely controlled under the condition of sufficient power supply, the remote control movement of the device and the automatic scanning of the DH251 Hall element array group (101) are realized, and the flexibility is increased.