Finned PTC air heater assembly for heating an automotive passenger compartment

An automotive passenger compartment heater comprising a housing unit having a pair of housing members disposed in spaced relation to each other at opposite sides of an opening extending through the housing unit;

• said housing members having slots therein adjacent respective opposite ends thereof, a pair of electrically conductive terminal means accessible from an exterior part of the housing unit and extending therein, a plurality of electrically conductive heat-exchanging fin means in electrical conductive relation to said terminal means disposed in the housing unit defining a plurality of fluid flow passage portions extending through the fin means for passing fluid through the housing unit opening through the fin means in heat-transfer relation to the fin means for heating the fluid, and self-regulating electrical resistance heater means having at least one body of ceramic material of positive temperature coefficient of resistivity with electrical contact means on two opposite sides thereof disposed in the housing unit between one pair of immediately adjacent fine means, thermally conducting grease disposed between the heater means and the immediately adjacent fin means for enhancing heat-transfer from the at least one body of the heater means to the fin means, spring means detachably mounted in the slots and extending between the pair of housing members at opposite end thereof for forming said housing unit, said spring means resiliently positioning the fin means, terminal means and the at least one body of the heater means with grease in thermally and electrically conductive engagement to be retained in the housing means and to define an electrical circuit electrically connecting the terminal means through the adjacent fin means and the at least one body of the heater means in sequence for electrically energizing the at least one body of the heater means to provide heat to the fin means for heating the fluid.