Patent ID: 9074819
Filing Date: 2015-07-07
Classification: F27D

Abstract:
1. An electrical heater, comprising: first and second heater elements, each having a U-shape metal tube to define an upstream and a downstream leg and tube ends of the tube adjacent each other, an electrical resistance wire extending through the tube, an insulation powder surrounding the wire within the tube, and an electrical terminal joined to the wire and protruding from each of the tube ends; a first conduit enclosing the upstream and the downstream legs of the first heater element and having a larger inner diameter than an outer diameter of the first heater element to provide a continuous annular flow path; a second conduct enclosing the upstream and downstream legs of the second heater element and having a larger inner diameter than an outer diameter of the second heater element to provide a continuous annular flow path; a manifold having a front, a back, and a plurality of heater element passages extending from the front to the back; an end portion of each of the legs of the first and second heater elements being inserted from the back into one of the plurality of heater element passages such that each of the terminals protrudes out from the front for connection to electrical power; an inlet passage in the manifold leading from an exterior portion of the manifold to the annular flow path surrounding the upstream leg of the first heater element; and a transfer passage within the manifold leading from the annular flow path surrounding the downstream leg of the first heater element to the annular flow path surrounding the upstream leg of the second heater element, so that fluid is first heated in the annular flow path surrounding the first heater element, then in the annular flow path surrounding the second heater element.