Abstract: An electric heater system includes an inlet, an outlet, a plurality of heat exchanger assemblies, and one or more connectors. The plurality of heat exchanger assemblies are connected in series. Each heat exchanger assembly includes a vessel, heating elements disposed within the vessel, and a fluid guide member. The connectors secure the vessels of the plurality of heat exchanger assemblies to each other. The connectors are also in fluid communication with the vessels. Fluid entering the inlet flows through the heat exchanger assemblies and through one or more connectors where it exits the outlet. The fluid guide members of the heat exchanger assemblies are of different or the same combinations to generate a predetermined pressure drop between the inlet and the outlet.

Abstract: A layered heater is provided that includes at least one resistive layer having a resistive circuit pattern, the resistive circuit pattern defining a length, a width, and a thickness, wherein the thickness varies along the length of the resistive circuit pattern and/or the width of the resistive circuit pattern for a variable watt density. The present disclosure also provides layered heaters having a resistive circuit pattern with a variable thickness along with a variable width and/or spacing of the resistive circuit pattern in order to produce a variable watt density.

Abstract: Methods of forming a layered heater are provided that comprise at least one resistive layer comprising a resistive circuit pattern, the resistive circuit pattern defining a length, a thickness, and a spacing, wherein the thickness varies along the length of the trace of the resistive circuit pattern for a variable watt density. The methods include achieving the variable thickness by varying a dispensing rate of a conductive ink used to form the resistive circuit pattern, varying the feed rate of a target surface relative to the dispensing of the ink, and overwriting a volume of conductive ink on top of a previously formed trace of the resistive circuit pattern.

Abstract: A layered heater is provided that comprises at least one resistive layer defining a circuit configuration, the circuit configuration comprising at least one resistive trace oriented relative to a heating target and comprising a material having temperature coefficient characteristics such that the resistive trace provides power commensurate with demands of the heating target. In one form, resistive traces of the resistive layer are a PTC material having a relatively high TCR and are oriented approximately perpendicular to a primary heating direction. In another form, resistive traces of the resistive layer are an NTC material having a relatively high BETA coefficient and are oriented approximately parallel to a primary heating direction.

Abstract: A layered heater is provided with a resistive layer having a resistive circuit pattern, the resistive circuit pattern defining a length and a thickness, wherein the thickness varies along the length of the resistive circuit pattern for a variable watt density. The present invention also provides layered heaters having a resistive circuit pattern with a variable thickness along with a variable width and/or spacing of the resistive circuit pattern in order to produce a variable watt density. Methods are also provided wherein the variable thickness is achieved by varying a dispensing rate of a conductive ink used to form the resistive circuit pattern, varying the feed rate of a target surface relative to the dispensing of the ink, and overwriting a volume of conductive ink on top of a previously formed trace of the resistive circuit pattern.