device for the evaporation of volatile substances, in particular insecticides and / or fragrances

摘要

The appliance to evaporate volatile substances e.g. insecticides and/or air fresheners, has an electrical resistance (15) to give a heating unit (10) of small dimensions with a rod resistance body (17) in a miniaturized appliance. The rod resistance body has an outer resistance coating (16) to give a structured resistance value, according to the composition of the volatile substances in use with the required heating temperature for evaporation. The coating is cut and/or ground in local zones, e.g. in a spiral cut (18). The resistance layer is a metal oxide and/or the resistance body is of ceramics.