SU1270669A1 - Magnetotelevison flaw detector - Google Patents

Abstract

The invention relates to instrumentation technology that converts the distribution of magnetic fields into a video signal. The aim of the invention is to increase the sensitivity of the flaw detector to internal defects by positioning a high-frequency decaying magnetic field. The flaw detector contains a field sensor connected in series, a current controller, to the second input of which a current source is connected, a DC electromagnet with compensation coils, a matrix magnetically sensitive node connected in series, a paraphase amplifier, a detector, an amplitude selector and a video monitor unit and a scanner connected in series, generator and high-frequency electromagnet. When the flaw detector is in operation, a matrix magnetically sensitive node is polled with a scanner and a field value is recorded on the video monitoring unit, and during the reverse C run through the frame, an additional high-frequency damping bias increases, which increases sensitivity. 2 Ш1. Yu

Description

The invention relates to measuring and control equipment and can be used to verify the quality of the structure of ferromagnetic materials and products. 5

The purpose of the invention is to increase the sensitivity of the flaw detector to internal defects by applying a high-frequency decaying magnetic field.

Figure 1 shows a block diagram of a magnetotelevision flaw detector; figure 2 - design of the magnetically sensitive node.

A flaw detector for monitoring an object contains a U-shaped direct current electromagnet mounted on the test object I, a 3-magnetic field sensor and a current regulator 4 connected in series, a current source 5 connected to the input of the current regulator 4, compensation coils 6 connected to the output of the regulator 4 current, the second output of which is connected to the winding of the U-shaped solenoid 2 DC. Defect-shown), placed on the surface of the object 1 control. The sweep unit 12 supplies current pulses of equal time with an amplitude equal to half the amplitude necessary to start the magnetization reversal of the ferrite cores 17 to the horizontal and vertical conductors 15 and 16.

The ferrite core, located 10th at the intersection of the corresponding horizontal and vertical wires, is magnetized. An EMF of electromagnetic induction is induced in the output winding 1e. The received signal 15 is amplified by a paraphase amplifier 8, detected by the detector 9, highlighted by the amplitude selector 10 and displayed at the corresponding point of the video monitoring unit 11.

Thus, each ferrite core is interrogated. At the end of the frame, the scan unit 12 delivers a powerful current pulse to the magnetization reversal bus 19 for simultaneously magnetizing magnetization of all the ferrite cores of the matrix to the original synchronoscope. It also contains a magnetically sensitive assembly 7 connected in series in the interpole space of the U-shaped direct current electromagnet 2, paraphase amplifier 8, detector 9 , amplitude selector 10 and video control unit 11.

The flaw detector also contains a scan unit 12 connected to the inputs of the magnetically sensitive unit 7 and a video control unit 11, and a function generator 13 connected in series to the output of the scan unit 12, and a high-frequency U-shaped electromagnet 14 mounted on the magnetically sensitive unit 7.

The magnetosensitive assembly 7 is made in the form of a matrix (Fig. 2) consisting of horizontal conductors 15, vertical conductors 16, ferrite cores 17, located at the intersections of horizontal and vertical conductors 15, 16 of a single-turn output winding 18 and magnetization reversal bus 19 passing through all ferrite cores 17.

Flaw detector works as follows.

Magnetosensitive assembly 7, made on an elastic basis (not.

In the absence of a defect, all the signals are the same in amplitude and on the video30 of the control unit - uniform glow. In the presence of a defect, the magnetic field of the defect changes the direction of the remanent magnetization of the ferrite core located in the defect zone; as a result, a lower EMF is induced in the output winding 18. In this case, the intensity of the glow of the screen of the video control unit at a given point accordingly changes.

At the time of the quenching pulse, the functional generator 13 generates an alternating current of high frequency, the value of which decreases from maximum to zero 45 in time; equal to the duration of the frame quenching pulse. The electromagnetic field that occurs in the high-frequency U-shaped electromagnet 14 increases the sensitivity of the magnetically sensitive assembly 7, which makes it possible to register magnetic fields of lower intensity.

Claims (1)

The invention relates to instrumentation technology and can be used to check the quality of the structure of ferromagnetic materials and products. The purpose of the invention is to increase the sensitivity of the flaw detector to internal defects by applying a high-frequency damped magnetic field. 1 shows a block diagram of a magneto-television flaw detector; Fig. 2 shows the construction of a magnetically sensitive node. A defectoscope for controlling an object 1 contains a U-shaped electromagnet with 2 constant current, installed at object 1 of control, connected successively with sensor 3 of a magnetic field and regulator 4 of current, current source 5 connected to input of regulator 4 of current, compensation coils: 6, connected to the output of current regulator 4, the second output of which is connected to the winding of the U-shaped electromagnet 2 of direct current. The flaw detector also contains magnetically sensitive in series: a node 7 located in the interpolar space of a U-shaped electromagnet 2 of direct current, a paraphase amplifier 8, a detector 9, an amplitude selector O and a video monitoring unit 11. The flaw detector also contains a scan unit 12 connected to the magnetosensitive inputs node 7 and a video monitor (5k P, and a functionally connected generator 13, connected to the output of the scanner unit 12, and a high-frequency U-shaped electromagnet 14, The magnetically sensitive node 7 is more complete in the form of a matrix (Fig. 2), consisting of horizontal conductors 15, vertical conductors 16 of ferrite cores 17, located at the intersections of horizontal and vertical conductors 15, 16 of a single turn output winding 18 and the magnetization reversal tires 19, passing through all the ferrite cores 17. The flaw detector works as follows: The magnetically sensitive unit 7, made on an elastic basis (not shown), is placed on the surface of the object I end trol Scanner 12 provides coherent current pulses of amplitude equal to half the amplitude needed to begin reversal of the ferrite cores 17 to horizontal and vertical conductors 15 and 16. The ferrite core located at the intersection of the corresponding horizontal and vertical wires is remagnetised. In the output winding I, EMF is induced by electromagnetic induction. The received signal is amplified by a paraphase amplifier 8, detected by detector 9, highlighted by amplitude villages: actor 10, and displayed at the corresponding point of the video monitoring unit 11. Thus, each ferrite core is interrogated. At the end of the frame, the scanner unit 12 delivers a powerful current pulse to the magnetization reversal bus 19 for simultaneously reversing all the ferrite serine matrices. in the initial state. In the absence of a defect, all signals are the same in amplitude and on the video monitor unit - a uniform glow. If there is a defect, the magnetic field of the defect changes the direction of the residual magnetization of the ferrite core that is in the area of the defect, as a result, a lower EMF is induced in the output winding 18. In this case, the intensity of the glow of the screen of the video monitoring unit at a given point changes accordingly. At the moment of the action of a frame damping pulse, the functional generator 13 generates an alternating current of high frequency, the value of which decreases from maximum to zero in a time equal to the duration of the frame damping pulse. Arising In this case, in a high-frequency U-shaped electromagnet 14, the electromagnetic field increases the sensitivity of the magnetically sensitive node 7, which allows detecting magnetic fields of lesser intensity. Magnetic television flaw detector containing U-shaped DC solenoid 5 in series 3.1 connected magnetic field sensor located in the interpolar space of the U-shaped DC electromagnet, current regulator and compensation coils located at the poles of the U-shaped DC electromagnet current in its interpolar space, a DC source, the output of which through a current regulator is connected to the winding of a U-shaped DC electromagnet, a solid node, made in the form of a matrix of ferrite cores, located in the interpolar space of a U-shaped DC electromagnet, connected to the magnetically sensitive node, the detector, amplitude selector and video control unit, and the scanner whose outputs are connected to the inputs of the magnetically sensitive node and the video monitoring unit, characterized in that, in order to increase the sensitivity of the flaw detector to internal defects, it is equipped with in series with a functional generator connected to the scanner, and a high-frequency U-shaped electromagnet mounted on a magnetically sensitive node. 73 12 X 0USJ Hno9t os. S X / o-