Patent ID: 6435174
Filing Date: 2002-08-20
Classification: F24H

Abstract:
A fluid heating apparatus comprising: a heater assembly including:a combustion chamber comprising a chamber perimeter wall defining a chamber interior, the chamber perimeter wall having an upper end and a lower end, the chamber interior being bounded by the chamber perimeter wall and the upper and lower ends of the chamber perimeter wall, the upper end of the chamber perimeter wall defining an upper opening into the chamber interior; a burner apparatus for burning fuel and heating the chamber interior of the combustion chamber, the burner apparatus being positioned adjacent the lower end of the chamber perimeter wall for directing combustion gases upwardly in the chamber interior toward the upper end of the chamber perimeter wall; and a heating conduit for moving fluid through the heater housing to heat the fluid, the heating conduit having an inlet and an outlet, the heating conduit including a preheating portion and a heating portion, the heating portion being positioned adjacent to the upper opening in the upper end of the chamber perimeter wall of the combustion chamber for permitting heat from the chamber interior to pass through the heating portion of the heating conduit, the heating portion comprising at least one tier, the tier comprising a spiral coil including a plurality of spirals lying substantially in a common plane; wherein the preheating portion comprises a helical coil positioned about the chamber perimeter wall such that the chamber perimeter wall is positioned between the chamber interior and the preheating portion of the heating conduit such that the heating conduit does not extend into the chamber interior of the combustion chamber, the preheating portion of the heating conduit abutting an outer surface of the chamber perimeter wall for absorbing heat from the chamber perimeter wall of the combustion chamber; and wherein the beating portion of the heating conduit is positioned above the upper end of the perimeter chamber wall and above the chamber interior of the combustion chamber such that the heating conduit does not extend into the chamber interior of the combustion chamber.