ELECTRIC HEATING SYSTEM FOR HEATING A FLUID STREAM

Abstract

An electric heating system for heating a fluid stream, the system comprising: a housing with an inlet for a fluid stream to be heated by the electric heating system and an outlet for the fluid stream heated by the electric heating system; and a resistance heater mounted inside the housing. The resistance heater comprises a fluid inlet and a fluid outlet, each fluidically connected to the inlet and outlet, respectively.coupled to the outlet are a plurality of annular walls made of an electrically conductive material, wherein the walls are nested to define a plurality of annular flow channels arranged serially concentrically around a longitudinal axis, wherein the walls extend between opposite first and second ends of the resistance heater separated from each other along the longitudinal axis, and first and second electrical connections for connection to a source of electrical energy to heat the walls of the resistance heater, wherein the first and second electrical connections are electrically connected to the respective first and second walls which are adjacent to each other and comprise an outer pair of walls which is arranged radially on an outside of the resistance heater.The plurality of annular walls are mechanically interconnected such that adjacent flow channels have opposite fluid flow directions and are connected at adjacent ends of the respective channels to define an alternating serpentine flow path. This path has an inlet end at the fluid inlet and an outlet end at the fluid outlet, with the inlet and outlet ends located at radially outer and radially inner positions, respectively, relative to the longitudinal axis. The plurality of annular walls are electrically interconnected to define a continuous electrically conductive path extending between the first and second electrical connections. The conductive path has a first part extending from the first wall to the center of the resistance heater and a second part extending from the center of the resistance heater to the second wall.