Patent ID: 6461520
Filing Date: 2002-10-08
Classification: C02F,H05B,Y10S

Abstract:
A method for energizing a filament of an ultraviolet lamp containing vapor and used for killing microorganisms in a water treatment unit, said method comprising the steps of:a) generating a signal to energize the filament of the ultraviolet lamp commensurate with discharge of water from the water treatment unit; b) limiting an initial current applied to the filament to a value insufficient to provide enough power to ionize the vapor in the ultraviolet lamp; and c) increasing the current applied to the filament to bring about ionization of the vapor in the ultraviolet lamp and generation of ultraviolet radiation from the ultraviolet lamp, said step of increasing including the use of a negative temperature coefficient resistor to control the value of the current as an inverse function of the temperature of the resistor.