Patent ID: 9316409
Filing Date: 2016-04-19
CPC Classification: F24D,F24H,Y02B

Claim Text:
1. A heat exchanger, comprising: a burner; a plurality of concentric spiral coils arranged about a common axis, wherein the outer diameters of each of the spiral coils are radially spaced apart from one another; wherein each of the spiral coils has one end in axial alignment with that of the other spiral coils, and wherein each of the spiral coils has an opposite end axially spaced from that of the other spiral coils; and an internal plate in axial alignment with the one end of the spiral coils; wherein the spiral coils have the same tubing diameter; wherein an outermost coil of the spiral coils is axially longer than the other spiral coils, and wherein an innermost coil of the spiral coils is axially shorter than the other spiral coils; wherein a condenser section including a plurality of U-bend coils is positioned downstream of the spiral coils; wherein the burner is positioned adjacent the opposite ends of the spiral coils, wherein there are three spiral coils, the spiral coils arranged to direct exhaust to the condenser section such that some of the exhaust from the burner flows to the condenser section through a first radial space between the innermost spiral coil and a middle spiral coil, wherein other of the exhaust from the burner flows to the condenser section though a second radial space between the middle spiral coil and the outermost spiral coil, wherein the exhaust flowing in the first radial space flows in parallel to the exhaust flowing in the second radial space such that exhaust exiting one of the first and second radial spaces flows to the condenser section without flowing through the other of the first and second radial spaces, and wherein the internal plate is arranged to direct exhaust interior to the innermost spiral coil to one of the first and second radial spaces; and wherein a manifold fluidly couples the U-bend coils and the spiral coils.