Ultraviolet water disinfecting action triggered by relay unit operating two heater coils in parallel

摘要

Operation of an ultra-violet emitter drinking water disinfecting assembly is preceded by a unit with two heating coils facing each other astride the gas discharge passage. Each UV emitter comprises two electrical connections for each coil. The unit preferably comprises a relay which operates the coils in parallel as required. Parallel operation is triggered by a four-bank relay. Before the UV emitter is triggered the relay connects the coils in parallel to a heating current. The length of cable between the relay switch unit and UV emitter is at least 8 (preferably more than 15) meters. Each coil is connected in parallel to an electrical capacitor. The heater relay is normally closed while the ignition voltage and operating voltage connections are made. Power to the coils is progressively increased by pulse width modulation or power limiter before the parallel connections are made.