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AssigneeXylem IP Management S.à r.I.
InventorsReiner Fietzek, Dirk Riepe
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A control algorithm for operating a fluid disinfecting system by UV radiation, wherein the UV radiation is generated by at least one UV lamp including a pair of heating cathodes having a discharge voltage (UD), the UV lamp is operated by an electronic ballast unit equipped with the control algorithm for adjusting the UV power of the UV lamp by pulse-width-modulation to reduce UV power. The control algorithm decreases the current to a level (Ikmin), increases the voltage amplitude (U) above the discharge voltage (UD) until a desired UV power level is reached. The pulse width (PW) is decreased with increasing voltage amplitude (U) until PWmin is reached. The decrease in current and the increase in voltage generate an ineffective current-voltage-ratio in which excess current heats the cathode. An electronic ballast equipped with the algorithm and systems equipped with such ballasts are also disclosed.
A method for controlling operation of a fluid disinfecting system by means of UV radiation, wherein the UV radiation is generated by at least one UV lamp comprising a pair of heating cathodes having a discharge voltage (UD), said UV lamp operated by an electronic ballast unit equipped with a control algorithm for adjusting UV power of the UV lamp by pulse-width-modulation to reduce UV power, the method comprising using the control algorithm of the electronic ballast unit to perform the steps of:
An electronic ballast unit for controlling a UV lamp comprising a pair of heating cathodes having a discharge voltage (UD), said electronic ballast unit equipped with a control algorithm for adjusting the UV power of the UV lamp via pulse-width-modulation by performing the steps of:
Dependencies are inferred from the claim text.