SU1564465A1 - Device for revealing missing insulation of pipes - Google Patents

Abstract

The invention relates to non-destructive quality control of pipe insulation and can be used to detect gaps in insulation coatings of main pipelines. The purpose of the invention is to increase the efficiency of the device. This goal is achieved by the fact that the operation of the device is based on the principle of repeated accumulation of energy on a storage capacitor. 1 il.

Description

The invention relates to non-destructive quality control of insulating pipe coatings and can be used to detect gaps in insulation coatings of main pipelines during their construction.

The purpose of the invention is to increase the efficiency of the device.

According to the invention, in a device comprising a DC source, a converter, a storage capacitor, a thyristor with a trigger pulse generator, a high-voltage transLormator, a test electrode, a spark-break detector and signaling means, the converter is made of a transformer whose primary winding is connected to the collector circuit of the transistor, the primary winding of which is included in the collector circuit of the transistor operating in the key mode, to the base of which the output of one-way is connected - a rator whose input is connected to an additional pulse generator, forming the necessary number of pulses for triggering the key transistor between the thyristor starts and the synchronization and control node between the outputs of the trigger pulse generator and the additional pulse generator input, ensuring that the time intervals between the pulses are constant formed by both generators.

The drawing shows the block diagram of the device.

The device contains a direct current source (batteries of batteries), transistor 2 wired to it, the primary winding of which is connected to the collector circuit of transistor 3 operating in the key mode. Secondary transformer winding

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2 through diode 4 is connected to a storage capacitor 5.

The key transistor 3 is controlled by pulses of a single vibrator 4 with an adjustable pulse duration by the controller 5. The single vibrator is triggered by a generator of 6 pulses.

The device also includes a thyristor 7, which serves to discharge the capacitor 5 through a high-voltage trans-separator 8, as well as a pulse generator 9 for starting the thyristor 7.

Between the generators 9 and 6, the synchronization and control unit 10 is switched on, ensuring a constant time shift between the pulses generated by the generators 9 and 6.

The spark-detector detector 11 is included in the secondary circuit of the high-voltage transformer 8, and the alarm node 12 is connected to the deflector 11.

The device works as follows.

 When a power source is connected to the device's electrical circuits, including transformer 2, at the moment of applying a positive pulse to the base of transistor 3 from the single-oscillator 4, a linearly increasing current flows through the primary winding of the transformer 2. In the magnetic field of transformer 2, energy is accumulated by law.

And Lidi,

where L is the inductance; i -., on current. When the transistor 3 is locked with the back front of the pulses of the one-shot 4, the energy accumulated in the magnetic field of the transformer 2 creates voltage pulses in its windings. A positive pulse from the output of the secondary winding passes through diode 4 and charges accumulative capacitor 5. Diode 4 prevents the discharge of capacitor 5 through the secondary winding of transformer 2..

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When applying control pulses

(with a frequency of 30-35 Hz) from the output of the generator 9 to the control electrode of the thyristor 7, the latter triggers, while the storage capacitor 5 is connected to the primary winding of the high-voltage pulse transformer 8. In the secondary winding

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A high voltage transformer is induced by a high voltage that is applied between a test electrode (probe) applied to the surface of the insulated pipe to be tested and a grounded wall of the metal pipe.

If a spark occurs between the probe and the grounded pipe wall in the presence of gaps in the insulating coating in the secondary winding of a high-voltage transformer, a current pulse occurs, which causes a signal at the output of the spark-break detector 11 and turns on the signaling node 12.

From the output of the generator 9, the pulses enter the synchronization and control device, which ensures a constant time delay of the pulses generated by the generator 6 relative to the pulses of the generator 9 and the disruption of the operation of the generator 6 at the moment of the appearance of the pulses at the output of the generator 9.

Thus, between two neighboring actuations of the thyristor 7, several identical (2-3) cycles of energy accumulating in the magnetic field of the transformer 2 and converting it into the electric field energy of the capacitor 5 occur. In this case, the total charge voltage of the storage capacitor is determined by

U (2-3)

where C is the capacitance of the capacitor; I is the discharge current.

Claims (1)

Invention Formula 1 A device for detecting gaps in pipe insulation, comprising a DC source, a converter with a storage capacitor connected to it, a thyristor with a trigger pulse generator, a high voltage transformer, a test electrode, a spark detector and signaling means, characterized in that The efficiency of the device, the converter is equipped with an additional pulse generator, a synchronization and control unit and a single vibrator with an adjustable pulse duration. f ph § § 0 I four