KR20050010433A - The Nondestructive Testing Apparatus for Wire Rope - Google Patents

Abstract

PURPOSE: A nondestructive testing apparatus for a wire rope is provided to detect defects including abrasion and corrosion by using a magnetic sensor. CONSTITUTION: A nondestructive testing apparatus for a wire rope(1) includes a magnetic sensor(2), a magnetic yoke(3), a permanent magnet(4), an input port, a measurement part(10), an AC frequency generating unit(9), and a voltage level measuring part. The magnetic sensor(2) has a GMI characteristic. The magnetic yoke(3) has a horseshoe type. The permanent magnet(4) is fixed to the magnetic yoke(3) and generates permanent magnetic force. The input port applies an AC current for inputting an AC frequency into the magnetic sensor(2). The voltage level measuring part measures a voltage level delivered from a measurement port.

Description

Nondestructive Testing Apparatus for Wire Rope

The present invention relates to non-destructive inspection of wire ropes, and more particularly, non-destructive wire ropes that can detect microdefects such as abrasion, corrosion, and disconnection existing inside or outside the wire ropes with less amplification rate and excellent sensitivity. It relates to an inspection apparatus.

In general, the most commonly used wire rope inspection methods are the visual inspection method and the electric field method.

The visual inspection method is uneconomical because it takes a lot of time to inspect, and in particular, it may be difficult for the inspector to approach the place where the wire rope is installed, and it is difficult for the inspector to take a stable posture. In addition to moving the wire rope for the inspection, it is difficult to ensure the safety of the inspection work because the inspector should be in close proximity.

On the other hand, the inspection method by the electromagnetic method is more reliable than the visual inspection method, but because it can not replace the visual inspection method completely, it is used in parallel with the visual inspection method, giving reliability, and is currently used mainly.

Looking at the inspection method by the electromagnetic system in more detail as follows.

1 is a block diagram illustrating a conventional leak magnetic flux flaw detector, comprising a wire rope (1) twisted in a plurality of lines, a magnetic yoke (3) wound around a coil to form a magnetic field, and a permanent magnet (4). And a magnetic closure circuit 12 formed by supplying the defect 5 generated in the wire rope 1 and the direct current or alternating current power supplied to the coil for electromagnet to use the magnetic flux of the magnetizing yoke to the magnetic yoke 3. And a hall sensor 13.

The conventional leak magnetic flux detection method detects a leak magnetic flux generated around a wire rope defect in a magnetic closed circuit with a magnetic sensor, and the leak magnetic flux detection method depends on variables such as rope thickness and physical properties in order to magnetize the wire rope. Since the magnetization strength should be different, the position of magnetization yoke and hall sensor according to rope should be properly adjusted.

In addition, the field-type wire rope flaw detector uses two highly sensitive holes, search coils, and fluxgate sensors, or focuses on the fact that the two wires are more than several times wider than those due to defects in the magnetic field distribution area where the rope is defective. The signal due to the defect was extracted by subtracting the magnetic field measured by.

However, since the operating range of the sensor itself is only a few gauss, the sensor cannot operate due to a large induction magnetic field of about tens of gauss generated when moving at a high speed in a strong magnetic field.

Therefore, in this case, a very complex magnetic shielding structure must be installed around the sensor in order to operate the sensor stably, and the arrangement of the sensor must be very precise in order to obtain the same magnetic shielding ability and output of the sensor. The defect detection technique of the rope by the conventional leak magnetic flux method has a high manufacturing cost and has a considerable difficulty in operating the device.

In addition, the inspection method of the conventional electromagnetic field method has a drawback in that it is difficult to apply portable equipment due to the large power consumption and the problem of miniaturization, and the inspection system of the electromagnetic field system is determined by the resolution and sensitivity in terms of performance. Since the output signal is small, a lot of amplification is required, and thus there is a problem such as noise.

The present invention is to solve the above-mentioned problems, it is possible to make a small size by a simpler method than the conventional electromagnetic field inspection equipment, using the AC magnetic resistance sensor with excellent sensitivity, wear, corrosion, disconnection, etc. present in the wire rope It is an object of the present invention to provide a non-destructive inspection device for wire ropes capable of inspecting defects.

1 is a block diagram illustrating a conventional non-destructive inspection device.

Figure 2 is a block diagram for explaining a non-destructive inspection device of the rope wire according to the present invention.

Figure 3a and Figure 3b is a block diagram for explaining the effect of the non-destructive testing device according to the present invention.

Figure 4a and 4b is a block diagram for explaining the implementation method according to the shape of the magnetic sensor implemented in the non-destructive inspection device of the present invention.

5A to 5C are graphs of defects of wire ropes detected by a magnetic sensor of a non-destructive inspection device of the present invention.

<Description of the symbols for the main parts of the drawings>

DESCRIPTION OF SYMBOLS 1 Wire rope 2 Magnetic sensor 3 Magnetization yoke

4: permanent magnet 5: wire defect

6a, 6b: outer first electrode terminal and outer second electrode terminal

7a and 7b: inner first electrode terminal and inner second electrode terminal

8 detection coil 9 AC frequency generator 10 measuring unit

In order to achieve the above object, a feature of the present invention is a non-destructive inspection device for inspecting internal and external defects, the magnetic sensor having a large alternating magnetic impedance (GMI) characteristics; Porcelain yoke with horseshoe shape; A permanent magnet fixed to the magnetic yoke to generate a permanent magnetic force; An input terminal for applying an AC current for inputting an AC frequency to the magnetic sensor; A detection voltage measurement terminal according to a change in magnetic impedance from the magnetized wire rope; An AC frequency generator for generating an AC frequency; It includes a measuring unit for measuring the voltage level transmitted from the measuring terminal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

Figure 2 is a block diagram illustrating a non-destructive testing device of the rope wire according to the present invention, the non-destructive testing device is a magnetic sensor (2) having a large alternating magnetic impedance (GMI) characteristics, magnetic yoke (3), and permanent It consists of a magnet 4, an outer first and second terminal 6a and 6b, an inner first and second terminal 7a and 7b, an alternating frequency generator 9 and a measuring unit 10. .

The nondestructive testing method using the nondestructive testing device having such a configuration is as follows.

First, when the wire rope 1 to be inspected by the permanent magnet 4 is magnetically saturated, the leakage flux 11 is generated at the defect 5 portion of the wire rope 1, and the magnetic frequency is generated from the AC frequency generator 9. The current delivered to the sensor 2 is changed in the magnetic impedance value by the leakage magnetic flux 11 generated by the defect 5, and thus the changed voltage is measured by the measuring unit 10 to detect the defect position.

That is, the magnetic signal is converted into an electrical signal to detect the position of a defect in the wire rope.

Here, the magnetic sensor 2 is formed of an amorphous material having a ferromagnetic layer on the surface, and is selected from the group consisting of Co or Fe-based amorphous magnetic ribbons, magnetic thin films made of soft magnetic materials, micromagnetic wires, and magnetic crystal materials. Is a material in which a ferromagnetic layer is formed on a surface of a magnetic material by heat-treating the magnetic field.

In particular, the magnetic sensor causing the large magnetic magnetic impedance phenomenon is a magnetic field such as magnetic thin films, amorphous ribbons, fine magnetic wires and magnetic crystals in the air or a specific gas (excluding inert gas) 1 ~ 3 Oe It is applied and produced by heat treatment at a temperature of 300 to 400 ° C.

The magnetic sensor fabricated in this way is recommended to use a frequency in the range of 100 kHz to 10 MHz. This is to measure at the most sensitive part about the magnetic change because the large magnetic impedance phenomenon (GMI) appears around 1 MHz. .

On the other hand, if there is a ferromagnetic material around the defect of the wire rope, the leakage magnetic flux signal may be distorted. Therefore, the magnetic sensor holder and the entire structure are made of non-magnetic material aluminum or magnetic shield material mumetal to prevent distortion of the leakage magnetic flux signal. It is desirable to.

The magnetic sensor using the above-mentioned giant magnetic impedance phenomenon can be connected in a four-terminal method or a two-terminal coil method.

In the four-terminal system, as shown in FIG. 3A, a magnetic field is formed by applying an alternating current I to the first and second terminals 6a and 6b of the magnetic sensor 2 and forming an inner side of the magnetic sensor. The impedance Z detected through the first and second terminals 7a and 7b is measured to find out whether the wire rope is defective or not.

That is, the four-terminal method is connected in the form of contacting the four terminals to the magnetic sensor (2).

In the two-terminal coil method, as illustrated in FIG. 3B, an alternating current I is applied to the first and second terminals 6a and 6b of the magnetic sensor 2 along the circumference of the magnetic sensor 2. After winding the detection coil a predetermined number of times, the impedance Z measured from the wound detection coil 8 is measured to find out whether the wire rope is defective or not.

That is, in the two-terminal coil method, two terminals and one coil are wound around the magnetic sensor 2.

The positional relationship between the magnetic sensor and the wire rope as described above may be implemented in a straight shape as shown in FIG. 4A, a circular shape as shown in FIG. 4B, and an array type implemented as a matrix. In particular, although various modifications may be made depending on the application and the application, the effects thereof are the same or similar.

Looking at the effect of the present invention through the data measured by the non-destructive inspection method and the non-destructive inspection device of the wire rope described above are as follows.

First, in this experiment, the specimen of the defective rope wire is secured, and then the length of the rope wire (unit: mm) is the X axis of the graph, and the voltage measurement value (unit: V) corresponding to the corresponding part is the Y axis. It was.

5A to 5C are graphs showing data measured according to the non-destructive testing method of the present invention.

In the specimen shown in Fig. 5a, there are four parts having a significantly high voltage value, which is measured by the influence of the leakage flux due to the wire break defect of the wire rope, and the X axis of each voltage value shows the corresponding specimen, that is, the rope wire. The location of the defect can be seen.

In the test piece shown in FIG. 5B, there are six parts having a significantly high voltage value, which is measured by the influence of the leakage flux due to the wire break defect of the wire rope, and the X axis of each voltage value shows the corresponding specimen, that is, the rope wire. The location of the defect can be seen. At this time, if you look closely at the sixth part from the right, it can be divided into three, which means that there are three defects adjacent to each other in the corresponding rope wire.

In the specimen shown in Fig. 5c, there are five parts with significantly high voltage values, which are measured by the influence of leakage flux due to defects caused by wear of the wire rope, and the X axis of each voltage value corresponds to the corresponding specimen, that is, the rope. Know where the defects in the wire exist.

According to the non-destructive inspection method of the present invention, defects such as disconnection of wire rope and wear can be easily diagnosed.

On the other hand, an alarm that sounds an alarm when the voltage level received from the measurement terminal exceeds a predetermined reference value, so that the inspector can easily use the results obtained through the non-destructive inspection method of the present invention, the defect of the corresponding wire rope. It is also possible to add a printing machine for printing the position in millimeter units, a display device for storing the defective position of the corresponding wire rope in a predetermined storage device and displaying the defective position of the stored wire rope.

According to a preferred embodiment of the present embodiment disclosed as described above, there is no need to install a very complex magnetic shield structure that can be seen in the existing inspection apparatus around the magnetic sensor, there is an advantage to increase the economics and portability, and to simplify the magnetic sensor It can be configured to detect the fine defects with excellent sensitivity, detect the internal and external defects of the rope wire, and the device operating method is convenient, so there is an advantage that can significantly increase the quality of the non-destructive inspection device.

Claims (8)

In the non-destructive inspection device for inspecting the defect of the rope wire, A magnetic sensor having a large alternating magnetic impedance (GMI) characteristic, Porcelain yoke with horseshoe shape, A permanent magnet fixed to the magnetic yoke and generating a permanent magnetic force, An input terminal for applying an AC current for inputting an AC frequency to the magnetic sensor, A measurement terminal serving as a passage of the voltage measured from the magnetized wire rope, AC frequency generator for generating AC frequency, It includes a measuring unit for measuring the voltage level transmitted from the measuring terminal, Magnetizing the wire rope, inducing leakage magnetic flux due to a defect of the wire rope, measuring a strained voltage due to the leakage magnetic flux, and detecting the presence or absence of a defect and a defect position of the wire rope according to the voltage level. Non-destructive inspection device for wire rope. The method of claim 1, The magnetic sensor is a non-destructive inspection device for a wire rope, characterized in that the at least one material selected from Co or Fe-based amorphous ribbon or wire, a soft magnetic material of the magnetic thin film, micromagnetic wire and magnetic crystals. The method of claim 1, The magnetic sensor is a non-destructive inspection device for a wire rope, characterized in that the ferromagnetic layer is formed on the surface by applying a magnetic field at a temperature of 300 ℃ to 400 ℃. The method of claim 1, The magnetic sensor is a non-destructive inspection device of the wire rope, characterized in that using the magnetic impedance effect using the AC frequency. The method of claim 1, And an alarm for outputting an alarm when the voltage level received from the measurement terminal exceeds a predetermined reference value. The method of claim 1, And a printer for printing the position of the wire rope in millimeter units when the voltage level received from the measuring terminal exceeds a predetermined reference value. The method of claim 1, Non-destructive inspection of the wire further comprises a display device for storing the position of the wire rope corresponding to the position when the voltage level received from the measuring terminal exceeds a predetermined reference value, and displays the stored position information on the screen Device. The method of claim 1, Non-destructive inspection device of the magnetic sensor to prevent the distortion of the leakage magnetic flux signal by adopting one of the holder and the entire case of the non-magnetic material aluminum or the magnetic shield material mumetal.