A device for removing static charges from the surface of sheet polymeric materials. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Ham Radio Technologies

 Comments on the article

Electrostatic charges on the surface of moving polymer sheet materials (for example, films) create a number of technological interferences, lead to defective products, adversely affect workers, worsen working conditions and create additional dangerous situations.

The removal of static charges from the surface of moving polymeric materials is solved in several ways, one of which is the ionization of the air surrounding the polymeric material. One of the sources of air ionization are high-voltage ionizers based on corona discharge, which have a high ionization capacity.

This article describes a device for removing static charges, which is designed for continuous non-contact neutralization of static electricity charges on the web of moving polymer sheet materials.

A block diagram of a device for removing electrostatic electricity is shown in Fig.1.

Device Specifications:

• The maximum speed of the movement of the material (film) ....... 70 m / min
• Supply voltage of neutralizers ....... 10 ... 12 kV
• High voltage frequency.......15...20 kHz
• Optimum neutralizer distance from moving material.......25...30 mm
• Number of ionizers.......2, 4, 6 pcs.
• Device supply voltage......220 V, 50 Hz
• Power consumption.......80 W

A high voltage of 10...12 kV with a frequency of 15...20 kHz is supplied from the transducer via a high-voltage cable to ionizers located on both sides of the neutralized film at a distance of 25...30 mm. Neutralizers are installed immediately before winding. The needle electrodes of the ionizer, together with the sharp edge of the body, create an electric field with a high density of field lines. The electric field accelerates the electrons in the air to a speed at which the energy of the latter is sufficient to split air molecules, especially oxygen. This produces both positive and negative ions. The spatial cloud of these ions recombines with the charge of the neutralized material. If the charge has a high potential (of the order of 1 kV and higher), then it can flow onto the grounded body of the ionizer through ionized air, which is a good conductor.

The electrical circuit of a high-voltage converter with a frequency of 15 ... 20 kHz is shown in Fig. 2.

(click to enlarge)

The converter is assembled according to the scheme of a half-bridge inverter on transistors VT1 and VT2. It is loaded on the primary winding of the T2 transformer, which galvanically decouples the high voltage from the AC mains. The self-oscillating mode of operation is provided by a voltage feedback circuit, which is taken from the winding III of the transformer T2 and fed to the winding I of the auxiliary transformer T1 and the launch unit assembled on the transistor VT3.

After switching on the switch SA1, the capacitor C5 is charged through the resistors R3, R6. When the voltage on it reaches approximately 50 ... 60 V, the VT3 transistor opens like an avalanche and the capacitor is discharged. The current pulse opens the transistor VT2 and starts the converter. After that, the negative half-cycles of the voltage from the base of the transistor VT2 periodically open the transistor VT3, keeping the capacitor C5 discharged.

The launch node does not participate in the operation of the device. If, for any reason, the oscillations in the converter stop, then the capacitor C5 begins to charge and the trigger unit generates a pulse that starts the converter. Resistor R7 can change the frequency of the converter.

The air ionizer (Fig. 3, where 1 is a high-voltage cable, 2 is a metal clip, 3 is an insulating sleeve, 4 is the metal case of the ionizer, 5 is a brass tube, 6 is metal needles) consists of a body, which is an aluminum or brass tube with a diameter of 30 mm with longitudinal holes. The edges of the holes are countersunk for sharp edges to create a high charge density.

Inside the case, a brass tube with soldered needles passes through the insulators, which are located exactly in the center of the annular holes in the case. A high-voltage cable passes through the inner tube, which together with the tube forms a small capacitor (about 15 pF). A small capacitance limits the amount of charge on the arresters. The ionizer needles are located at a distance of 1...2 mm from the surface of the ionizer body. The length of the ionizer is selected in each case depending on the width of the strip of the processed material.

Setting. It is necessary to connect the ionizer to the converter with a high-voltage cable. Then, connect a frequency meter and an oscilloscope to the ends of the winding I of the transformer T1.

The power is turned on and after the generation occurs, its frequency is estimated and, observing the shape and amplitude of the oscillations, the optimal frequency is set with resistor R7.

Details. Transistors VT1 and VT2 type KT809A can be replaced by KT812A. They must be installed on radiators with an area of ​​at least 50 cm2. Capacitors C1 and C2 type K73-17; C3 and C4 type K50-12; C5 type KM-6. Transformer T1 is wound on a 2000NN ferrite ring with dimensions K10Ch6Ch5. The primary winding contains 50 turns, the second and third windings - 8 turns each with PELSHO-0,25 wire.

The T2 transformer is wound on an NMS2000 ferrite core from a TVS-110L line transformer. Windings I and III are wound with PELSHO-0,33 wire and contain 90 and 5 turns, respectively. The high-voltage coil of a horizontal transformer is used as a secondary high-voltage winding.

Author: V.F. Yakovlev

See other articles Section Ham Radio Technologies.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Processing moon dust into oxygen 09.11.2020 Materials technology company Metalysis has won a contract with the European Space Agency (ESA) to develop a method to extract oxygen from lunar dust and soil. Also, the company, which is based in South Yorkshire, will extract iron, aluminum and other metals from lunar resources. They will be useful for building a base on the moon. Metalysis has received about £250 (about $000) from ESA to improve the technology in the extraterrestrial environment. This was told by the managing director of the company Jan Mellor. A few months earlier, Metalysis technologists said they could extract 96 percent of the oxygen from lunar regolith found on the surface of Earth's natural satellite. And from the remains of rocks - to create a metal alloy that can be used in construction. The method, which has already been tested on Earth, was invented at the University of Cambridge. If the technology is successfully implemented, space missions will be able to use the resources that are already on the moon. And not deliver them from Earth. After all, such a delivery is "a very expensive pleasure," said Jan Mellor.

Other interesting news:

▪ Climate change causes bees to deform

▪ Cheap ICs - Signal Generators

▪ USB keys for accessing sites

▪ A new way to discover coral reefs

▪ Boat jet engine on outboard water

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Voltage stabilizers. Article selection

▪ article Don't Touch My Blueprints! Popular expression

▪ article What color is your brain? Detailed answer

▪ article Mint penny. Legends, cultivation, methods of application

▪ article Fundamental problems of the development of electric power industry based on renewable energy sources in Russia. Encyclopedia of radio electronics and electrical engineering

▪ article The riddle of the torn poster. Focus Secret

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024