SU1415043A1 - Device for non-destructive check - Google Patents

Abstract

The invention relates to non-destructive testing and can be used to determine the thickness of a dielectric coating on ferromagnetic products in the form of plates and tapes, for example, on an electrical steel strip. The aim of the invention is to expand the functionality of the device, which is achieved by providing the ability to measure the thickness of a nonmagnetic coating on a ferromagnetic substrate. During the operation of this device, a controlled article 6 made of a ferromagnetic material is placed between the poles of the U-shaped magnetic conductors 1, 3 in the gap 5. A 12-current source is switched on, which creates a common-state magnetic flux through the compensation winding 4 with the magnetic flux created by the current source 11 and the magnetizing winding 2. The device circuit automatically maintains the specified flux rate in the magnetic circuit 1. By using the compensation principle of operation, the device allows obtaining an output parameter proportional to the thickness of the monitored coating, i.e. The indications of the indicator of the controlled parameter 13 are proportional to the dielectric thickness: the coating, regardless of the uneven thickness of the ferromagnetic base, as well as the change in its magnetic properties, which contributes to improving the measurement accuracy and expands the functionality of the device. 1 il. CD Lo

Description

one

The invention relates to methods 1 | destructive testing and can be used to determine the thickness of a dielectric coating on ferromagnetic products, plates and tapes made into aida, for example, electrical insulation coating on electrical steel tape,

; The aim of the invention is to expand the functionality 5 of the device by measuring the thickness of a non-magnetic coating on a ferromagnetic substrate.

The drawing shows the structure- | ha scheme of the proposed device.

I The device for non-destructive- Control contains a U-shaped magnet cable with a magnetizing winding 2, a second and a type of magnetic core 3 with a compensation winding 4, Stopped facing towards each other with a gap 5 designed to accommodate the controlled product 6 The measuring winding placed on the first U-shaped magnet 1, located between the rods of the i-shaped magnetic circuits and 3 in the zone of the working gap 15, the flow sensor 8, the magnetic flux indicator 9 connected to it, the current-fcbeMHbtfi resistor 10, first th and second Sources 11 and 12 of the current, to the outputs jcoTopbK are connected, respectively, to the Magnetic Gateway and Compensation Tracks 2 and 4, the indicator 13 of the monitored parameter, the subtracting unit 14, connected to its input, the second indicator 15 of the magnetic flux, the second and third subtractive blocks 16 and 1 flow setting unit 18, magnetomotive force setting unit 19, a scaling unit 20 and two supra mounts 21 and 22, while the measuring winding 7 is connected to the first input of the second reading unit 16 through the first rectifier 21, the second input of which is connected to out the house of block 18, and the output of the second subtractive block 16 is connected to the control input of the first current source 1, the second rectifier 22 is connected to the magnetizing winding 2 and the current pickup resistor 10, and the output to the first inputs of the first and third read blocks 4 and 17, the output of the latter is connected to the second flow indicator 15, and the output of the magnetomotive force setting unit 19 is connected to the second

0

five

0

five

thirty

35

40

45

50

55

th input of the third subtractive unit 17 and through the scaling unit 20 to the second input of the first subtractive unit 14.

Device for non-destructive: control works in the following way.

In the calibration cycle, which is carried out in order to prepare the device for operation, the magnetic cores 1 and 3 are closed with each other (without a plate with an electrically insulating coating), as a result of which a closed magnetic circuit is formed. In this case, the flow of an alternating sinusoidal current with amplitude I through the magnetizing winding 2 from the current source 11, with the source 12 disconnected, causes the magnetization reversal of identical magnetic cores 1 and 3 with the amplitude of the magnetic flux equal to F, which causes the appearance in the measuring winding 7 of the EMF rectifier 21 to a constant voltage level 11 K f, where K, is the proportionality coefficient, depending on the parameters of winding 7 and rectifier 21. The level enters the second input of the second subtracter block 16, on the first input of which, using the flow setting block 1 устанавливает, sets the voltage level and K Fr, where F is the optimal magnetic flux value set for operation of the device. In this case, the difference signal from the output of the downstream unit 16 acts through the control input of the current source 11 in such a way that in a closed magnetic circuit the value of the flux with the amplitude Ф Ф is set, which corresponds to the zero level at the output of the subtractive unit 16.

For the considered magnetic circuit and steady state (), the ratio

F F 2R (1) 1 o m

where F is the magnetomotive value

force (MDS) generated by the source 11 in the winding 2j magnetic resistance of the magnetic circuit I (or magnetic field 3 identical to it) with the amplitude of the magnetic flux equal to F. The alternating voltage from the collector resistor 10 is proportional to

R - m

- 314

the value of VAT F is converted by the transducer 22 into a constant voltage level, which arrives at the first input of the third subtraction unit 17 and is equal to Uj K F, where K is a proportionality coefficient depending on the number of turns of the winding 2, resistance of the current collector resistor 10 and the transfer coefficient of the rectifier 22. At the output of block 19, the MDS setting and, respectively, at the second input of the third subtractive block 17 set a level of constant voltage equal to the level and 3, which corresponds to the zero level at the output of the subtracting block 17 and the corresponding Essentially zero indicator of indicator 15. Level C - is converted by scaling unit 20 to level

  B

g

or in accordance with the relation (1)

U4. (2) which is fed to the second input of the first subtraction unit 1A.

Thus, in the process of preparing the device for operation, a constant voltage level is formed at the second input of the first subtraction unit 14, proportional to the magnitude of the magnetic resistance R

wires 1 at the amplitude of the flow in the magnet conductor F f

In the process of testing between the poles of the magnetic cores 1 and 3, a controlled article 6 made of a ferromagnetic material with a dielectric coating is placed into the gap 5 and an alternating current source 12 connected through the compensation winding 4. -Ac. Magnetic flux, in sync with the magnetic flux created by the source 11 (by connecting sources 11 and 12 to the same voltage source). By varying the amplitude of the current of source 12, the magnetic flux in the ferromagnetic product 6 is equal to zero, which corresponds to the equipotentiality of points a and b and, accordingly, to the absence of a signal at the output of the flow sensor 8 and the zero reading of the indicator 9 zero. In this case, the circuit for automatically maintaining a given value of the flux in the magnetowire 1 provides the amplitude of the flux Ф Фо in the first magnetically

de 1, and hence the equality of the magnetic resistance of the magnetic circuit 1 to the value of R j. .

In connection with the equipotency of Tofochek a and b for a closed magnetic circuit formed by a magnetic core 1, a ferromagnetic product 6, and portions of a dielectric coating under the poles of the magnetic circuit 1, the ratio

F 2R),

(3)

where R is the magnetic resistance of the dielectric section

of the coating under one pole of the magnetic circuit I, F is the magnet of the magnetomotive

forces in the winding 2, which ensures the flow F in the magnetic conductor 1 in the absence of flow in the product 6, at the output of the detector 22, a level of constant voltage 25 and J о of the subtraction unit 14 is formed, at the second input of which in the process of preparing the device for operation voltage level set

It - g

thirty

and, K, 2

As a result, a constant voltage level of 35 is formed at the output of the first subtraction unit 14 and, accordingly, at the input of the indicator 13 of the coating thickness

and and, and,)

or taking into account the ratios (l) and (W)

Ug 2Ro W Considering the fact that the magnetic resistance R is determined by the known

 J.

- s

(five)

1 - coating thickness,

S - the area of a sectioned pole magic ™

Nitropipe 1 | fU is a magnetic constant.

Indicator 13 readings are proportional to the thickness of the dielectric coating with a precisely known proportionality coefficient.

This device ensures the independence of results from variations in the thickness of the product being monitored and its magnetic properties by eliminating 51415043

These factors are among the factors determined by the fact

output parameter, which allows to implement the compensation principle of the device.

Claims (1)

Invention Formula ; A device for an unbreakable I control, containing an i-shaped magnet line with a magnetizing winding; and a second i-shaped magnet line with a compensation winding, installed end-to-end with each other Idruga with a gap, designed to accommodate a controlled item , the measuring winding placed on the first H-shaped magnetic circuit, located between the terminals of the tl-shaped magnetic circuits in the area of the working gap, the flow sensor, the magnetic flux indicator connected to it, the current-collecting resistor; The second and second current sources, to the outputs of which are connected respectively the magnetizing and compensation windings, the indicator of the parameter being monitored, the subtracting unit and the indicator of the parameter being monitored connected to its output. characterized in that, in order to expand the functionality by measuring the thickness of a non-magnetic coating on a ferromagnetic base, it is equipped with a second magnetic flux indicator, second and third subtractive blocks, flow reference blocks, a task block of magnetomotive force, a scaling unit and straighteners , measuring LD; 1, the winding through the first rectifier is connected to the first input of the second subtractive unit, the input of which is connected to the output of the flow reference, and the output of the second subtractive unit It is connected to the control input of the first current source, the rectifier input is connected to the magnetizing winding and the collector resistor, and the output is connected to the first inputs of the first and third subtractive blocks, the output is connected to the second flow indicator, and the output of the magnetomotive force reference block is connected to the second the input of the third subtraction unit and through the scaling unit to the second input of the first subtraction unit.