Method and device for improving the efficiency of treating fluids applied to a uv reactor

A method for improving the efficiency of treating fluids applied to a UV reactor comprising a longitudinal flow chamber having a longitudinal center axis, an input for entry of fluid in the flow chamber, and an output for fluid to exit the flow chamber, where at least the input of the flow chamber comprises an inlet pipe followed by an inlet cone which as a part of the flow chamber increases the cross section of the channel from the inlet pipe to a cross section of the longitudinal flow chamber of UV reactor, said UV reactor having at least one longitudinal UV-lamp parallel to but not coinciding with the longitudinal center axis, and where the UV-lamp is arranged such that fluid can flow along a flow path from the input to the output via the flow chamber, and so that fluid flowing along the flow path can be exposed to UV-radiation as it flows from the input to the output to receive a Reduction UV dose, wherein the fluid applied to the UV reactor via the input of the flow chamber, when passing the inlet cone in combination with a flow guide located in said inlet cone, is applied a uniform helical flow path in an extent that all the fluid applied to the UV reactor, within the operation range of the current UV reactor, at least passes at least one UV-lamp at a distance to receive at least a prescribed Reduction UV radiation dose related to the current UV reactor, during passing of the fluid inside the UV reactor.