US 4,241,874 A · Heat exchanger

Abstract

An improved heat exchanger (74) for use with a heating furnace (72) is disclosed. The exchanger (74) includes a first plurality of tubes (84) which conduct hot exhaust gases from the furnace (72). Tubes (98) carrying outside air for combustion in the furnace (72) pass proximate the first group of tubes (84) within a heat exchange chamber (90) wherein heat is transferred to the combustion air via a heat transfer medium. Similarly, ambient air in the building passes through the heat exchange chamber (90) of the exchanger (74) through a third plurality of tubes (118). These tubes (118) also pass proximate the tubes (84) carrying hot exhaust gases. In a preferred embodiment, a conduit (80), through which the exhaust gases transit from the furnace (72) to the first plurality of tubes (84) in the heat exchanger (74), can be routed through plenums (110, 126) through which combustion air and ambient air circulate after exiting the second and third pluralities of tubes (98, 118).

Claims18

Dependent claims

A heat exchanger for use with a heating furnace, comprising:

a cabinet;
a first plurality of tubes extending through said cabinet, each of said tubes having first and second ends;
means for introducing exhaust gases from the furnace into first ends of said first plurality of tubes;
a second plurality of tubes extending through said cabinet, each of said second plurality having first and second ends, said first end of said second plurality being in fluid communication with outside air;
means for conveying outside air in said second plurality of tubes from said second ends to the furnace burner;
a third plurality of tubes extending through said cabinet, said third plurality having first ends in fluid communication with ambient air inside the home;
means for transmitting air inside said third plurality of tubes from second ends thereof to the return air blower of the furnace;
and
heat transfer medium in said cabinet surrounding portions of said first, second, and third pluralities of tubes disposed within said cabinet.

6 more elements

In combination with a furnace system wherein the furnace includes a burner which draws combustion air from outside the building in which the furnace is housed, a heat exchanger for cooling exhaust gases from the furnace and removing moisture therefrom before the exhaust gases are vented from the building, for warming outside combustion air before it reaches the burner, and for pre-warming cool inside air before recirculating it through the furnace, comprising:

a conduit carrying exhaust gases from the furnace;
a housing including first and second chambers and an intermediate chamber positioned between said first and second chambers, said first chamber in fluid communication with said conduit;
a first plurality of tubes having first and second ends in fluid communication with said first and second chambers respectively, said first plurality extending through said intermediate chamber;
a first outlet plenum enclosing a first portion of said conduit;
a second outlet plenum enclosing a second portion of said conduit;
an inlet plenum;
means for conducting outside air for combustion into said inlet plenum;
a second plurality of tubes extending through said intermediate chamber, said tubes having first ends in fluid communication with said inlet plenum and second ends in fluid communication with said first outlet plenum;
a third plurality of tubes extending through said intermediate chamber, said third plurality having first ends in fluid communication with ambient air inside the building in which the furnace is located and second ends in fluid communication with said second outlet plenum;
liquid medium disposed in said intermediate chamber, said medium surrounding portion of said first, second, and third pluralities of tubes extending through said intermediate chamber;
means for conveying combustion air in said first outlet plenum to the furnace burner;
means for transmitting ambient air in said second outlet plenum to the return air blower of the furnace;
and
means for draining moisture of condensation from said first plurality of tubes.

11 more elements

Dependencies are inferred from the claim text.

Heat exchanger

Life of this patent

Heat exchanger

Life of this patent

Abstract

Claims18