Patent ID: 8680437

Claim:
Heating system for a liquid conveyor system comprising: at least one first heater, comprising a PTC element, for defrosting a liquid, said at least one first heater located within a tank or adjacent to a pump; and at least one filter heater for heating a filter for liquid filtering, said at least one filter heater comprising at least one winding embedded in a plastic filter cup, said at least one filter heater being connected in series with said at least one first heater, said at least one first heater heating the tank or pump and protecting the at least one filter heater in the plastic filter cup from overheating; and wherein the at least one filter heater is provided as a resistance heating element formed by a heating section of an electrical connecting line of the at least one first heater, wherein at temperatures below freezing the electric resistance of the at least one first heater is higher than the electric resistance of the at least one filter heater.