Plasma Technology
The high energy level of the plasma (300 degrees) can temporarily break the structure of chemical or organic substances on the surface of the material. Thanks to precise cleaning, even sensitive surfaces can be completely cleaned of unwanted process residues. This results in optimal conditions for subsequent coating, painting and bonding. Atmospheric Quantum Plasma surface treatment ensures 100% hygiene without the use of chemicals. Quantum plasma provides a hydrophilic surface, allowing materials to be processed immediately.
Quantum Plasma is a collection of positively and negatively charged particles that are completely electrically neutral and move in random directions. A solid substance in thermal equilibrium, usually at a constant pressure, turns into a liquid by increasing its temperature. If the temperature is increased a little more, the liquid turns into a gas. When the temperature is further increased, electrons are detached from gas atoms and gas atoms decompose into freely moving charged particles (positive ions and electrons) and turn into plasma, the fourth state of matter.
Plasma contains electrons, ions, photons, excited atoms or molecules, radicals, metastable atoms, notral atoms. The reactive particles formed in the plasma cause various modifications on the surface in the form of surface activation, cleaning, abrasion, etching, grafting, cross-linking without disturbing the basic properties of the material.
Atmospheric Plasma
The Plasma Nozzle (where the arc intensity is created) is the place where the plasma is created and at the same time the point where electricity and gas are combined. This part is made of stainless steel outside and brass inside. This part is produced in the form of a quartz tube. The stainless steel tip allows it to work like an electrode with the help of high voltage and high frequency (pulse). It is connected to a DC power supply with the help of a 100Mohm resistor. Here the resistor is used to limit the discharge current. The distance between the nozzle and the quartz tube is about 5mm. The radius of the steel nozzle tip is about 100lm and the inner diameter of the quartz tube is 1mm.
The above-mentioned operations should be carried out in the open air. During the application, the gas flow must be controlled by mass flow control. When a high voltage of 12kV is applied to the nozzle and the air is allowed to flow through the quartz tube at a gas flow rate of 3l/min, a homogeneous air plasma and nozzle slug is formed at the nozzle tip.
High Voltage Transformer
High voltage transformer is the circuit element that enables the electricity to be increased to the desired high voltages in order to provide arc formation, which plays an active role in the formation of plasma. This is achieved with the help of circuit elements and microprocessors used in power electronics. In the high voltage transformer, the voltage can be increased and decreased to the desired levels, thus ensuring the formation of the desired plasma level according to the condition of the surface to be applied. Increasing the voltage is not enough for these processes. The frequency must also be increased. We can increase the 50Hz frequency used in the city network up to 25kHz thanks to the circuit and oscillator on our control and power card. This can be adjusted with the adjustment pot on the device. Thanks to these adjustment pots, the output voltage and frequency can be increased or decreased to the required levels.
There will be two different electronic cards in the device. The first of these will be the power card. It will have power electronics circuit elements (diodes, mosfets, capacitors, etc.) and the power is disconnected from the control. The other board is the board where the microprocessor and adjustment potentiometers are located. With this card, there is circuit software that enables the display of voltages and frequencies on the screens and the operation at the desired levels.
The working algorithm of the system is increased depending on the number of voltage windings in the high voltage transformer and the working principle of the transformer and high voltage low current is obtained. The frequency is switched with the help of the oscillator in the microprocessor and the desired frequency levels are obtained. In this way, by increasing the voltage and frequency, we reach the electrical level that will enable the arc to form at the output end.
The circuit board required to obtain plasma is superficially expressed in this way. Afterwards, arc formation starts in the nozzle. But the arc temperature can reach up to 6000 degrees. We need to reduce that heat to 200-250 degrees with air. If the heat is not reduced, there may be an explosion. The arc is formed in such a way that it jumps from polarity to neutrality. This arc is formed with compressed air. In this area, the air rotates in a curved manner and moves to the process surface. This movement is called vortex. As the air rotates, it gains speed and exits the arc by rotating. The arc also follows the air.
When the arc contacts the surface in this way, heat is transferred. A heat of 200-250 degrees is given to the surface. This heat is sufficient for the particles to evaporate. Another feature of the process is that the process is completed in a short time. Under normal conditions, a very high energy consumption is required to reach this temperature. But with this method, it is realised with an energy consumption between 500-800 watts. We can perform this process by applying high frequency and high voltage instantaneously.
Magnetic Field Power Electronics Design
In order to create the high-voltage circuit required for the creation of plasma, the windings in the transformer carry electricity through electromagnetic interaction in the primary and secondary windings. During this transport, electricity can be raised and lowered to the desired levels in situations such as the number of windings and cable cross-section. By using the magnetic field, the electricity is increased to the desired levels. How many times the voltage applied to the input will be increased is determined by the number of windings.
Frequency Amplifier
The frequency, which is one of the factors that form the basis of the operating functions, enables the frequency to be increased or decreased to the desired levels by switching at the desired levels with the pulse modulation of the microprocessor. In this way, the frequency can go from 50Hz to 25kHz.
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