Cold plasma air decontamination

• Main Author: Redzuan, Norizah
• Published: University of Glasgow 2010
• Subjects: 628.5; TJ Mechanical engineering and machinery
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.586737

Cold Plasma Discharges offer wide decontamination scenarios relevant to environmental, food and drink or clean room applications. The option to operate the discharge system in atmospheric or sub-atmospheric condition provides an opportunity to investigate a lowcost and simple system design. UV to NIR (200nm to 700nm) can be emitted by pulsed cold plasma discharge systems that operate at atmospheric pressure. Different wavelengths emitted from the discharge depend on the pressure and the type of gas mix used in the systems. The scope of the work involved in this research was to design and develop a prototype cold plasma system for air at atmospheric pressure. The prototype was used for air decontamination by passing seeded and unseeded air between the electrodes gap. Modelling of the discharge and pulse forming network circuit systems was carried out in MultiSim to investigate the circuit characteristic. The components values ie: capacitors, stray inductors and resistors in the model system are interchangeable which enabled simulation of individual component effects on the output pulse shape and magnitude. The optimum component properties from the modelling were used as a guide to designing the system. The main discharge system contained a pair of Chang Uniform Field Electrodes which were manufactured in-house, and provided a discharge area of 1.0cm x 60.0 cm. The discharge volume is varied depending on the gap between of the anode and cathode. Preionisation was achieved via trigger wire, built within the discharge system. This promotes the ionisation of the gas in between the electrodes in enhancing uniform discharge characteristics. Different types of electrodes were made from aluminium with the discharge size 300mm x 200mm, laser marked and unmarked surface were also used in the system in order to obtain wider discharge surface and reduce manufacturing costs.