SU1479869A1 - Ferromodulational magnetotelevision flaw meter - Google Patents

Abstract

The invention relates to the field of non-destructive testing and can be used in industry for recording the internal structure of ferromagnetic materials and products. The aim of the invention is to increase the sensitivity and broaden the dynamic range of the flaw detector by optimizing the selection of the operating point of the magnetically sensitive node. When the item is monitored, the signal from the magnetically sensitive node after processing is stored in memory block 5 and, as frames accumulate, is displayed on the screen of video control block 6 as a bright picture characterizing the product structure. At the same time, the low frequency filter 7 extracts the information signal envelope and compares it with a predetermined value. According to the results of the comparison, a bias current is produced, which corrects the operation of the magnetically sensitive node in the optimal region. 2 Il.

Description

3 s4

CO 00

oe with

fie.1

The invention relates to non-destructive testing and can be used in industry for recording the internal structure of ferromagnetic materials and products.

The aim of the invention is to increase the sensitivity and broaden the dynamic range of the flaw detector by optimizing the selection of the operating point of the magnetically sensitive node. FIG. 1 shows a block diagram of the device; in fig. 2 is a diagram of a magnetically sensitive node.

The device contains a magnetization unit 1, a magnetically sensitive node 2 connected in series, a video amplifier 3, an amplitude selector 4, a memory block 5 and a video monitoring unit 6, as well as a low-pass filter 7 connected to the second output of the video amplifier 3, block 8 comparison, generator 9 step voltage and bias current-shaping amplifier 10 and control unit 11, the outputs of which are connected to the magnetosensitive node 2, memory unit 5, video monitoring unit 6 and comparison glare 8

In addition, the device contains a generator of 12 pulses and two switches 13 and 14, connected respectively between the first and second outputs of the generator, 12 pulses, and the third and fourth outputs of the generator 9 of step voltage.

FIG. Figure 1 denotes a test article 15 placed between the magnetization unit 1 and the magnetically sensitive node 2.

The magnetically sensitive node 2 contains toroidal ferrite cores 16.1-16.N (FIG. 2) placed in a ruler, a generator 17 of remanufacturing pulses, a magnetic biasing winding 18 connected to a generator of magnetization reversing pulses 17, a biasing magnetic winding 19 connected to a shaper 10 bias current, output winding 20 and vertical address bus 21, which, together with all windings 18, 19 and 20, pierce all toroidal ferrite cores

sixteen.

In addition, the magnetically sensitive node 2 contains the address decoder 22 and current keys 23 connected between

the outputs of the address decoder 22 and the vertical address tires 21. The device operates as follows.

The magnetically sensitive node 2 is moved along the surface of the test article 15 after it is magnetized by the magnetization unit 1. Using the power of the oscillating pulse generator 17, the address decoder 22, and the current keys 23, the toroidal ferrite cores 16 are sequentially polled.

5, the output winding 20 is fed to the video amplifier 3 and, after amplification, through an amplitude selector 4, into memory block 5, where it is memorized. After accumulating the entire television frame by the signals of the control unit 11, the memory block 5 is sequentially polled, the received information signal is displayed in the form of a bright picture on the video screen5 of the control block 6.

In order to select the optimal transfer characteristic, the signal from the low pass filter 7 is simultaneously supplied to the comparison unit 8, where

0 is compared with the reference value. Depending on the magnitude and sign of the deviation, the keys 13 or 14 are opened, and the pulses from the pulse generator 12 are fed to the generator 9 s.

5 step voltage where a signal is produced to control the biasing driver 10 of the bias current. The resulting bias current enters the winding 19 of the sub magnetising, correcting the sensitivity of the magnetically sensitive node 2 to the optimum value.

Claims (1)

Formula of the invention Ferromodulation magnetotelective flaw detector containing a magnetization unit, connected in series magnetosensitive a node made as a single-line converter on toroidal ferrite cores, a video amplifier, an amplitude selector, a memory unit and a video control unit, and a unit controls whose outputs are connected to a magnetically sensitive node,. a memory unit and a video monitoring unit, characterized in that, in order to increase the sensitivity and increase the dynamic range of the flaw detector, it is equipped with a low-pass filter connected to the output of the video amplifier, a comparison unit, a step voltage generator and a bias current driver, a generator impulses and two keys included respectively, between the first and second outputs of the pulse generator and the third and fourth inputs of the step voltage generator, and the magnetically sensitive node is provided with a bias winding covering all toroidal ferrite cores and connected to the output of a biasing current amplifier. Cf / WЈt0M30tft / #  g / zaggusn FIG. 2