Patent ID: 8647585

Claim:
Plasma sterilisation apparatus comprising: a plasma applicator having an enclosed plasma generating region and an outlet for directing plasma out of the plasma generating region towards a surface to be sterilised; a microwave radiation generator connected to deliver microwave energy into the plasma generating region; and a gas feed connected to deliver gas into the plasma generating region, wherein the apparatus is configured to create an impedance at the plasma generating region, the impedance being high enough to enable striking of a non-thermal plasma for delivery out of the applicator, wherein the microwave radiation generator comprises a controller arranged adjustably to control the microwave energy delivered to the plasma generating region, wherein the plasma generating region is formed in a plurality of coaxial applicators, each coaxial applicator comprising: an outer conductor, an inner conductor, a coupler located at an input end thereof for coupling the microwave energy from the microwave radiation generator to the plasma generating region, and a gas inlet for delivering gas from the gas feed to the plasma generating region, and wherein the apparatus further comprises: a high voltage generator and a plurality of igniters, each igniter being coupled into the outer conductor of a respective one of the plurality of coaxial applicators in such a manner to generate, based on a control signal from the controller, a high electric field between the inner and outer conductors of the respective one of the plurality of coaxial applicators to strike the non-thermal plasma for delivery out of the plasma applicator, the controller being arranged to control the microwave radiation generator to deliver the microwave energy to maintain the non-thermal plasma after it is struck.