RU1786693C - Method of neutralization of static electricity on moving surface of dielectric - Google Patents

Abstract

Usage: a method of neutralizing static electricity on a moving surface of a dielectric is intended to neutralize moving dielectrics in light, pulp and paper, printing and chemical industries. SUMMARY OF THE INVENTION: the method is carried out by stabilizing the current of the discharge screen. The current from the power source entering the discharge is divided by the neutralization current (through the corona electrode) and the screen current. The neutralization current appears in the presence of a charge on the surface of the dielectric and increases with increasing charge. The screen current is stabilized by comparing the feedback formed by the RC circuit with the reference voltage. The voltage difference is applied via a control device to the high voltage source. In this case, the reference voltage is set depending on the discharge in such a way that, in the absence of a charge on the neutralizable dielectric, the neutralization current is minimal. 2 ill. with

Description

The invention relates to techniques for protecting objects from harmful manifestations of static electricity and can be used in the development of processes for neutralizing moving dielectrics for light, pulp and paper, printing, chemical and other industries.

The aim of the proposed method is to increase the efficiency of the neutralization process.

The goal is achieved as follows. As is known, the current from the high voltage source n in the arrester is divided into the screen current e and the neutralization current IH of the charges on the surface of the dielectric, i.e. In e + n. When a charge appears on the dielectric, the neutralization current 1H increases, the screen current b decreases accordingly, and the feedback voltage decreases.

The feedback voltage is compared with the reference voltage, and their difference is applied to the high voltage source. In this case, the reference voltage is selected depending on the discharge in such a way that, in the absence of a charge on the material to be neutralized, the neutralization current is minimal, i.e. ln e

Since the screen current is stabilized (according to the proposed method), the high voltage source automatically increases the output current, trying to keep the screen current constant. Thus, the complete neutralization of charges of surface electricity occurs automatically, and in order to influence a charge with a larger absolute value

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accordingly, a larger neutralization current is supplied, while the absolute charge on the dielectric surface decreases, the neutralization current decreases.

The device acts on unipolar charges; to neutralize charges of a different polarity, a second device is required that is configured to neutralize charges of the opposite sign.

Technical solutions are known in which separate devices are used to neutralize charges of different polarities. However, none of the known methods provides the necessary and sufficient potential in absolute value to the corona electrode to completely neutralize the surface.

Fig. 1 is a block diagram of a power supply; in FIG. 2 is a schematic of the action of the discharge

Designations in the drawings: CB - network rectifier; And - inverter; UM - voltage multiplier; VT - high voltage transformer; UU - control device; OU - operational amplifier; U feedback voltage; Uon is the reference voltage; In is the current from the power source; 1E is the current of the discharge screen; n is the charge neutralization current; VN - high voltage; K - high voltage electrode; E - screen.

The converter consists of a high voltage source and an arrester. The high voltage source is a pulse block with stabilization of the current of the discharge screen.

Discharge.consists of a high-voltage electrode (a number of needles, a thread ...) and a shield, grounded through a measuring RC circuit.

The device operates as follows. .

The mains voltage is supplied through the rectifier, inverter, step-up transformer and multiplier to

high voltage electrode. In the arrester, the current from the source is divided by the neutralization current and the screen current. The screen current, passing through the measuring RC circuit, forms the feedback voltage Kos, which is fed to the input of the operational amplifier and is compared with the set reference voltage Uon. Further, the amplified signal of their difference is fed to the input of the control device. Thus, the high voltage source is a source of stabilized screen current.

Output current In "bmkA.

Thus, the implementation of the method makes it possible to increase the efficiency of the neutralization process due to the absence of ion recombination when the discharge sign changes on the high-voltage electrode and due to automatic adjustment to any surface charge, and the process of adjusting the device to certain materials, thickness, and speed of movement is excluded.

Formula of the invention

A method of neutralizing static electricity on a moving surface of a dielectric by forming charges of the opposite sign on this surface, formed by a neutralization current of a corona discharge electrode included in a circuit of a high voltage source together with a discharge screen loaded with an earthed RC circuit, excluding moreover, and in order to increase the efficiency of the neutralization process, the reference voltage is set so that, in the absence of a charge on the neutralized surface, the neutral current ation was minimal, and the current screen to be converted to voltage RC-circuit is continuously compared with a reference voltage and the difference between them is produced m the management source of high voltage.

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