COMPACT, HIGH EFFICIENCY HEAT EXCHANGER FOR A FUEL-FIRED FORCED AIR HEATING FURNACE

摘要

A compact, high efficiency heat exchanger for a fuel-fired forced air furnace has horizontally spaced apart inlet and outlet manifold structures which are innerconnected by a horizontally spaced series of vertically serpentined, relatively small diameter flow transfer tubes. Larger diameter inlet flow tubes are positioned beneath the balance of the heat exchanger, extend parallel to the transfer tubes, and have upturned discharge ends connected to the underside of the inlet manifold. The heat exchanger is configured so that its total vertically facing peripheral surface area is considerably larger than its total horizontally facing peripheral surface area, thereby significantly reducing undesirable outward heat loss through the vertically extending furnace housing side walls upon burner shut off and increasing the overall efficiency rating of the furnace. To reduce the manufacturing cost of the heat exchanger its components are assembled using a weldless fabrication process which includes swedging the tubes to the manifolds and forming each manifold from two sections which are edge rolled and crimped together.