SU964564A1 - Device for photography in high-frequency currents - Google Patents

Description

one . The invention relates to devices for photographing in a high-frequency electric field and can be used to detect defects that cannot be detected with the naked eye. A device for producing photographs by the Kirlian method is known, which contains a high-frequency Tesla transformer, a voltage regulator, a signal indicator of a process, and a switch for shooting and high voltage. The housing cover, which serves as the top cover plate for the film, has in its upper part a recess into which the glass plate is inserted. There is another notch on the lower side of the lid, into which a metal plate is inserted which serves as an electrode to which a high voltage is applied. The bottom side of the electrode (opposite to the glass plate) is covered with an insulating layer,. The closest technical solution to the invention is an electric-spark defectoscope containing a high-voltage transformer with low and high voltage windings, a probe connected to a high voltage winding, a source of pulsating voltage (T generator) of a low voltage winding, a threshold switch through which the winding low voltage related to. the generator, an electric-spark-breakdown indicator connected to the grounded lead of the high voltage winding 2, The disadvantage is the inability to photograph objects from different materials and different shapes without reducing the image quality with high performance. The aim of the invention is to increase the reliability of operation. This goal is achieved by the fact that a device containing in series, a connected voltage generator, a key and a high-voltage transformer with low and high voltage windings and electrodes is equipped with a power amplifier, a time relay, a feedback circuit and a control unit, while the output of the control unit connected to the input of the feedback circuit, the second input and output of which are connected respectively to the output and input of the voltage generator, and the output of the time relay is connected to the input of the key, the output of which is connected to the input of l power output connected to the winding of the low voltage high voltage transformer.

In this case, one of the electrodes is made transparent.

FIG. 1 shows a block diagram of the device; in fig. 2 - placement of the object in the process of photographing.

The device comprises a series-connected voltage generator 1, control key 2, amplifier: 3 power, high voltage transformer A, replaceable electrodes 5 and 6. The voltage generator 1 is equipped with an adjustable feedback circuit and control unit 8. Time relay 9 is connected to control input of key 2.

The device works as follows. .

The voltage generator 1 generates sinusoidal oscillations from 10 to 25 kHz. The frequency tuning of oscillator 1 is necessary to select the optimal mode and provide the greatest clarity of the image of the object. The signal from the output of generator 1 is fed to the input of key 2. Controlled key 2 has two states, Closed and Open, determined by the operation of time relay 9.

When the start button (not shown) is pressed, a positive potential appears at the output of the time relay 9, which control key 2 is transferred from the closed position to the open position, and the signal from the voltage generator 1 passes through switch 2 to the input of the power amplifier 3 . The time during which the controlled key 2 remains in the Open state is determined by the position of the time switch 9. The exposure time is set and selected in the range of 0.1-90 seconds. After the time set by the switch at the time of the output of the relay 9 expires, the potential of zero appears and the control key 2 goes into the Closed state, the output circuit of the generator 1 from amplifier 3 is broken.

A sinusoidal signal from the output of the control key 2 is fed to the input of the amplifier 3 power. From the exit

0 power amplifier 3, the amplified signal is fed to the low voltage winding of a high voltage transformer k, and a high voltage is applied to its secondary winding, which is applied to electrodes 5 and 6. Electrodes 5 and 6 are interchangeable and their shape and design depend from the photographed object. For example, electrodes 5 and 6 can be made in the form of flat capacitor plates, in the form of a rotating roller, they can be rigid or elastic. A corona discharge occurs between the electrodes 5 and 6 under the action of a high potential, with the result that an image of the object is formed on the photographic carrier superimposed on the object to be photographed.

The voltage generator 1 is made

0 with stabilization of the amplitude of the output voltage, which is carried out by an adjustable feedback circuit 7. The adjustment of the output voltage of the generator 1 is carried out by the control unit 8 of the feedback circuit 7.

The power amplifier 3 is made with a push-pull output and a differential input. The power amplifier 3 circuit with a differential input provides zero DC potential with respect to the common busbar, which eliminates the constant reversal of the core of the high-voltage transformer and allows the load to be switched on without the separation capacitor.

Claims (2)

When photographing small flat objects (hand, sheet of wood, flat metal parts, etc.), flat electrodes 5 and 6 (Fig. 2) are applied. The upper electrode 6 is made transparent, which provides visual observation of the 5th state object 10 and the intensity of the corona discharge. Such an electrode can be made, for example, from organic glass in the form of a flat bath. On the inner side of the side wall of the bath there is a metal electrode 11 connected to one of the terminals (with zero potential) of the high-voltage winding of the transformer (FIG.). The bath is filled with a transparent liquid electrolyte (for example, salt water and closed with a transparent lid 1) The photographing process is carried out as follows. A photographic object 10 is mounted on the lower electrode 5, onto which the upper electrode 6 is then mounted. Turn on the power, set the exposure time sufficient for visual observation of the object being illuminated. With knobs (not shown) voltage and frequency adjustments are achieved, the maximum The image and contrast of the object, then a photo material (not shown) is superimposed between the object 10 and the upper electrode 6, set the exposure time (determined experimentally) and turn on the high voltage with the Start button. Between the photographing object 10 and the upper electrode 6 a high potential occurs corona discharge, followed by a luminescence of the object that is exposed to the photographic material. Then the photographic material is shown and fixed in the usual way. White paper can be used as a photocarrier. The image is black and white: the protruding parts of the object are black, and the recesses are light. If you use a leaf of a tree as an object, then its image is obtained in the form of a sheet with well-marked images of veins. When photographing the hand, an image of the hand with a clear selection of the bone skeleton is obtained. The device can also be used to detect defects in current-conducting materials. The detection of defects is carried out as follows. The controlled object is connected to one of the terminals of the high voltage winding of the high voltage transformer 4. A transparent electrode 6C6 (Fig.2) is mounted on the surface of the object to be monitored. By varying the frequency and voltage at the output of the device, the maximum brightness and contrast of the image of the area of the object covered by the transparent electrode 6 are achieved. After that, the transparent electrode 6 is moved along the surface of the object to be monitored. Defects in the controlled object (cracks, voids, foreign inclusions, etc.) are detected as dark areas with a bright outline bordering the defect. Thus, the device allows to change the frequency of the sinusoidal oscillation over a wide range (10-25 kHz) over a wide range (1-5 kV), to automatically set the corona discharge time (exposure time 0.1-9.0 cj). The invention also provides increased reliability of the device operation: due to the inclusion of a controllable key between the generator and the low voltage windings of a high voltage transformer - Invention 1. A device for photographing in high frequency currents containing An inherent voltage generator, a switch and a high-voltage transformer with low and high voltage windings and electrodes, differing in that, in order to increase reliability, it is equipped with a power amplifier, a time relay, a feedback circuit and a control unit, while the output the control unit is connected to the input of the feedback circuit, the second input and the output of which are connected respectively to the output and input of the voltage generator, and the output of the time relay is connected to the input of the key, the output of which is connected to the input of the power amplifier, output ohm connected to the low voltage winding of high voltage transformer. 2. The device according to claim 1, from l and the fact that one of the electrodes is made transparent. Sources of information taken into account in the examination 1.Patent of Germany No. 2527976, cl. G 03 B, pub. 1975. 2. USSR author's certificate number A26181, cl. D, 01 N 27/62, 1971 (prototype).