Abstract: A ventilation system has a filter apparatus which comprises a porous filter media 10 arranged to trap micro-organisms contained in a fluid flow along a duct 14 of the apparatus, and a lamp 13 for irradiating the filter media 10 with ultraviolet light, the filter media 10 being formed of a fluroplastics material which is substantially transparent to the ultraviolet light so that micro-organisms trapped inside the pores of the filter are irradiated and killed by the ultraviolet light. The ventilation system alternatively or additionally comprises a filter apparatus which comprises a porous filter media 40 formed of an electrically conductive material arranged to trap micro-organisms contained in a fluid flow along a duct 42 of the apparatus, and a coil 25 for irradiating the filter media 40 with electromagnetic radiation so as to heat the filter media 45 and thereby kill any micro-organisms trapped by the filter media 40.

Abstract: A fluid disinfection apparatus 10 comprises a disinfection chamber 12 through which fluid to be disinfected flows, and an ultra-violet (UV) lamp 14, operable to output UV light at a germicidal wavelength. First and second fluid inlets 18, 20 and first and second fluid outlets 22, 24 are selectively opened to define a fluid flow path through the disinfection chamber 12. Cleaning apparatus 16 is provided on the UV lamp 14 and comprises a cleaning head 42, a drive plate 46 and four vanes 48. To clean the UV lamp 14, a fluid flow path from the first fluid inlet 18, through the disinfection chamber 12 to the second fluid outlet 24 is defined. Fluid entering the disinfection chamber 12 engages the drive plate 16 and vanes 48, thereby driving the cleaning apparatus 16 along the UV lamp 14 and cleaning the UV lamp 14.

Abstract: An irradiation device, for example a UV irradiation device for disinfecting waste water, is arranged to emit radiation from a source and through an outer wall which is permeable to fluid. Means are provided for varying the fluid pressure behind the inner surface of the outer wall, to cause fluid to permeate through it, either inwardly or outwardly. The arrangement serves to maintain the outer surface of the permeable wall clear of contaminants.

Abstract: An apparatus for disinfecting air flowing along a duct in an air conditioning or ventilating system, includes a head portion which is mounted to the outside of the duct, and a body portion extending from the head portion and inserted into the duct through an aperture in its side wall. The body portion supports one or more ultra-violet lamps dispose in respective UV-transparent sleeves and a device is provided for causing a flow of, for example, air through the sleeves in order to control the temperature of the lamps.