converted and evaporated through the use of the woven tangled configuration 54 which is heated as a result of direct contact with the wall 4 as already illustrated in fig6 the region of the spray cone can also be kept free of the woven tangled configuration 54 in this case so that the droplets 45 impinge directly on the wall 4 the embodiments of the evaporation unit 1 which are shown in fig4 5 6 and 7 may likewise advantageously be used in a device 47 fig8 shows by way of example a wall structure 42 which may be chosen for one of the exemplary embodiments according to fig4 to 7 as well as for an exemplary embodiment having a channel 3 as an evaporator cavity 2 the evaporator cavity 2 is delimited by the wall 4 which is constructed from titanium the heat imparting layer 5 made of aluminum and or copper is connected in a thermally conductive manner to the wall 4 a heating layer 6 is connected on the outside in a materially integral manner in particular brazed to this heat imparting layer 5 in this exemplary embodiment the heating layer 6 includes from the inside outward an inner contact layer 49 a self regulating heating resistor 50 and an outer contact layer 51 the self regulating heating resistor 50 is electrically contacted and operated through the use of the inner layer 49 and the outer contact layer 51 this heating layer 6 may be surrounded on the outside by thermal insulation and heats the heat imparting layer 5 the inner contact layer 49 self regulating heating resistor or conductor 50.