An ozone generator is a device used for generating ozone gas (O3). Ozone is prone to decomposition and cannot be stored. It needs to be produced on-site for immediate use (in special cases, it can be stored for a short period of time). Therefore, any place where ozone is needed must use an ozone generator. Ozone generators are widely used in drinking water, sewage treatment, industrial oxidation, food processing and preservation, pharmaceutical synthesis, and space sterilization. The ozone gas produced by the ozone generator can be directly utilized or mixed with a liquid through a mixing device to participate in the reaction.
I. Principle of Ozone Generator
The working principle of the corona discharge ozone generator: Dry oxygen or oxygen-containing gas flows through the corona discharge area composed of internal and external electrodes. In this discharge area, high-frequency high-voltage electrical energy of several thousand volts is applied, causing the raw gas flowing into the discharge area to be ionized and generate ozone.
2. Principle of electrolytic ozone generator: Ozone is generated through the electrochemical oxidation of water. In water containing hydrated fluorescent anion electrolytes, at approximately room temperature and with a high current power, water can be oxidized into ozone.
II. Circuit Diagram of Ozone Generator
The parameters that need to be controlled for the ozone part mainly include concentration and flow rate. The flow rate can be achieved simply by adjusting the corresponding regulating valve. However, the ozone concentration is related to many factors, such as the gas source, power supply, the structure of the generator, and the cooling method. In this design, the working frequency of the ozone generator is mainly adjusted to achieve the regulation of ozone concentration.
While keeping the gas flow rate constant, adjust the output frequency of the inverter power supply of the ozone generator. As the working frequency changes, the high-voltage discharge power also changes, thereby achieving the regulation of ozone concentration.
The ozone generator in this article uses the medium-impedance corona discharge method to produce ozone. It mainly consists of an air pre-treatment system, a cooling system, an electrical power supply, a discharge chamber, and an ozone tail gas destroyer system. The schematic diagram of the ozone generator covered in this article is shown in the figure, which involves pressurizing air with an air compressor into a gas purification and dehumidification device, then introducing the dry and clean air out of the device into the ozone generation tube. The high-voltage power supply supplies power to the ozone generation tube, and discharges between the electrodes, causing the air flowing through the ozone generation tube to form a certain concentration of ozone. Since during corona discharge, the temperatures of the electrodes and the dielectric surface will increase, which accelerates the decomposition of ozone, the ozone generation tube must be cooled to control the working temperature inside the tube within a certain range.
The early power supply system of ozone generators adopted the direct voltage boosting method based on industrial frequency. The advantage of this method is its simple structure. However, since industrial frequency operation requires a high voltage peak to achieve the desired power induction, the insulation performance of the windings is demanding, and the winding manufacturing process is relatively difficult. Moreover, during industrial frequency operation, the transformer is large in size, the ripple and stability are not satisfactory, and the ozone generation efficiency is low. Currently, the rapidly developing power electronics is applied to switching power supply technology, making high-voltage power supplies high-frequencyized has become a trend. It can be raised to 50-100 kHz, or even up to 13.56 MHz. Now industrial-type ozone generators basically adopt medium-high frequency inverter power supplies, using PWM and soft-switching technology. The working frequency is generally in the range of 400-2000 Hz, which greatly improves the performance of the device and reduces the equipment size.
