Intertherm, Inc.

Hongsik Ahn

A compact secondary heat exchanger, installed in the path of room air through the casing of a gas furnace, utilizes a unitary condensing coil having parallel upper, middle and lower sets of tubes through which the flue gas passes sequentially to a collector manifold, exhausted by a blower. The coil is slanted downwardly from the hot gas manifold. Condensate formed in the first and second sets of tubes flows downward to an intermediate manifold between the first and second sets of tubing, condensate from this intermediate manifold is drained downward to a collector manifold beneath.

Water vapor-condensing secondary heat exchanger

For use with a hydrocarbon-fueled furnace whose secondary heat exchanger so cools the combusted gas as to condense much of its water vapor, and having a blower to the flue, a combined trap and drain is provided for the condensate formed both in the heat exchanger and in the flue. At the base of the flue is a standpipe whose upper overflow outlet is connected to a dip tube. Between the level of its lower end and the overflow level is a side inlet into the standpipe, connected to a tube leading downward from the heat exchanger's condenser. When the furnace blower applies both negative pressure to the condenser and positive pressure to the flue, the water levels in the trap and tube adjust to balance out these pressures.

Drain for condensate from flue gas

A compact secondary heat exchanger, installed above the preliminary heat exchanger in a down draft-type gas burning furnace, so greatly reduces combustion gas temperature as to recover a portion of the latent heat in the water vapor created by burning the hydrocarbon gas.

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Chesterfield, MO, United States of America

Hongsik Ahn