Fluid heater coil configuration and fabrication method

Abstract

A spiral fluid heater coil system for facilitating drainage of fluid from the heater and increasing the efficiency of transferring heat to a fluid. The spiral fluid heater coil system includes a heater assembly including a combustion chamber having a chamber perimeter wall defining a chamber interior. The chamber perimeter wall has an upper end and a lower end, with the upper end of the chamber perimeter wall defining an opening into the chamber interior. The heater assembly includes a burner apparatus for burning fuel and expelling heat into the chamber interior of the combustion chamber, with the burner apparatus being positioned adjacent the lower end of the chamber perimeter wall for directing heat upwardly in the chamber interior toward the upper end of the chamber perimeter wall. The heating assembly includes a heating conduit for moving fluid through the heater housing to heat the fluid. The heating conduit has a heating portion positioned adjacent to 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 includes at least one tier, and the tier comprises a spiral coil having a plurality of spirals lying substantially in a common plane. Preferably, the heating conduit includes one or more pairs of tiers, in which an upper tier is oriented above a lower tier, and an innermost spiral of the lower tier is connected to an innermost spiral of the upper tier such that fluid is moved from an outermost spiral of the lower tier to the innermost spiral of the lower tier to the innermost spiral of the upper tier to an outermost spiral of the upper tier.