Abstract: A duct (10) for use in an ultrasonic treatment plant is made from a cylindrical steel pipe (12) by plating the bore with a corrosion-resistant metal layer (14). This is preferably done by honing the bore to ensure that it is circular, plating the bore of the pipe (12) with the corrosion-resistant metal, and again honing the bore of the pipe to ensure that it is circular and to reduce the thickness of the corrosion-resistant metal, and coupling ultrasonic transducers (16) to the outside of the pipe (12). Where flanges (22) are attached to the ends of the pipe (12), these are fitted over each end of the pipe so the ends are flush, and welded to the outside of the pipe (12).

Abstract: A reactor (1) particularly for the plasma treatment of internal combustion engine exhaust gases, in which a power supply (10) and a reactor bed (2) of the dielectric barrier discharge type are connected directly and enclosed in an earthed metal chamber (17) which both isolates the high voltage power supply and acts as a Faraday cage preventing the emission of electromagnetic radiation from the power supply or plasma.

Abstract: A reactor (100) for the plasma assisted processing of a gaseous medium, including a cylindrical bed (106) of active material (107) contained between two concentric electrodes (108, 109), both of which are earthed and with a third cylindrical electrode (111) concentric with the other electrodes positioned within the bed of active material (107) and connected to a high voltage input terminal (112).

Abstract: A reactor for the plasma-assisted processing of gaseous media comprising a reactor chamber including a gas permeable bed of active material, a power source for applying across the bed of active material a potential sufficient to establish a plasma in a gaseous medium flowing through the bed of active material and a chamber having an inlet stub and an outlet stub for constraining the gaseous medium to flow through the bed of active material, wherein the bed of active material comprises a matrix of beads of a dielectric material having an assembly of regular arrays of beads in each of which adjacent beads are connected to a high voltage input terminal or an electrical ground.

Abstract: A reactor particularly for the plasma treatment of internal combustion engine exhaust gases, in which a power supply and reactor bed are connected directly and enclosed in an earthed metal chamber which both isolates the high voltage power supply and acts as a Faraday cage preventing the emission of electromagnetic radiation from the power supply or plasma.