Back to results
US 5,205,276 AGranted
Compact furnace heat exchanger
AssigneeGas Research Institute
InventorsMichael A. Aronov, Roger D. Sheridan
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeGas Research Institute
InventorsMichael A. Aronov, Roger D. Sheridan
Estimating the term…
A compact heat exchanger for a fuel-fired heating furnace. The heat exchanger has a radiative heat transfer section including at least one firetube for containing flue gases as the air to be heated passes over the firetube and a convective section including a shell-and-tube heat transfer apparatus arranged to receive flue gases from the firetube in the shell region and the air to be heated after it passes over the firetube in the tubes.
A heating system comprising a compact heat exchanger including a first heat transfer conduit means disposed within a first surrounding enclosure that substantially surrounds the first conduit means, and a second heat transfer conduit means disposed within a second surrounding enclosure that substantially surrounds the second conduit means, said first conduit means being in fluid communication with said second enclosure and said first enclosure being in fluid communication with said second conduit means, burner means for burning air and fuel to form products of combustion and for conveying the products of combustion through the heat exchanger, and blower means for flowing air to be heated through said heat exchanger and to a space to be heated, said burner means being operatively connected to said heat exchanger to convey said products of combustion through said first conduit means and said second enclosure, and said blower means being operatively connected to said heat exchanger to flow air to be heated through said first enclosure and said second conduit means, said second conduit means including a plurality of tubular members having longitudinal axes extending through said second enclosure, said second enclosure including wall means providing a serpentine flow path for said products of combustion extending transversely back and forth across the longitudinal axes of said tubular members and through said second enclosure, said second enclosure and said wall means confining the path of the products of combustion as they enter the second enclosure to a cross-section that is sufficiently less in dimension, measured in the direction of the longitudinal axes of said tubular members, than the effective lengths of the tubular members to permit the wall means to divide the second enclosure into at least three transverse paths across the tubular members and of generally equal cross-sectional area.
A heating system comprising a compact heat exchanger including a firetube enclosure and an air tube enclosure, burner means for burning air and fuel to form products of combustion and for conveying the products of combustion through the heat exchanger, and blower means for flowing air to be heated through the heat exchanger and to a space to be heated, said burner means including at least one elongated firetube disposed in said firetube enclosure for containing products of combustion and transferring heat energy from the combustion products to air to be heated flowing over substantially all of said firetube, said air tube enclosure including a plurality of air tubes arranged to receive therein heated air from said firetube enclosure for further heat transfer with said combustion products from said at least one firetube flowing over said air tubes, each of said air tubes having a generally tubular configuration and a longitudinal axis extending through said air tube enclosure, said air tube enclosure including wall means providing a serpentine flow path for said combustion products transversely back and forth across the longitudinal axes of said air tubes and through said air tube enclosure in a plurality of transverse passes, said air tube enclosure end wall means confining the path of combustion products as they enter the air tube enclosure to a cross-section that is sufficiently less in dimension, measured in the direction of the longitudinal axes of the air tubes, than the effective lengths of the air tubes to permit the wall means to divide the air tube enclosure into at least three transverse paths across the air tubes and of generally equal cross-sectional area.
A heating system comprising a compact heat exchanger including a firetube enclosure and an air tube enclosure, burner means for burning air and fuel to form products of combustion and for conveying the products of combustion through the heat exchanger, and blower means for flowing air to be heated through the heat exchanger and to a space to be heated, said burner means including at least one elongated firetube disposed in said firetube enclosure for containing products of combustion and transferring heat energy from the combustion products to air to be heated flowing over substantially all of said firetube, said air tube enclosure including a plurality of air tubes arranged to receive therein heated air from said firetube enclosure for further heat transfer with said combustion products from said at least one firetube flowing over said air tubes, the air tubes having inlet openings adjacent said firetube, the firetube having a longitudinal side facing, free of obstruction, a plurality of said air tube inlet openings such that radiation from said firetube can directly enter said openings and provide further heat transfer between said combustion products and air by radiation from said firetube to said air tubes.
Dependencies are inferred from the claim text.
Drawings are temporarily unavailable. Open the PDF at USPTO
By tubes: using fluid fuel
Fluid heaters
Term ended 21 Nov 2011 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
1. Field of the Invention
The invention relates generally to heat exchange systems and is particularly directed to a compact gas-to-air heat exchanger and to a heating system incorporating the heat exchanger.
2. Description of Related Art
FIG. 1 is a perspective view of a furnace or heating apparatus including a compact heat exchanger embodying the principles of the invention with parts omitted or broken away to show the inner components thereof;
FIG. 2 is a front plan view of the furnace shown in FIG. 1;
FIG. 3 is a side plan view of the furnace shown in FIG. 1; and
A fuel-fired furnace 10 includes a blower assembly 12, a burner assembly schematically shown at 14, and a compact heat exchanger 16 having a radiative heat transfer section or enclosure 18 and a convective heat transfer section or enclosure 20 as shown in FIGS. 1-3. The blower assembly 12 is arranged to flow air to be heated upwardly through the radiative section 18 and the convective section 20 of the heat exchanger 16 and then to the space to be conditioned as indicated by the arrows "A". The products of combustion or flue gases flow along a serpentine flow path through the heat exchanger 16 as indicated by the arrows "C" and transfer a significant amount of the sensible heat energy to the air to be heated prior to being exhausted through a furnace vent 22 for discharge to the atmosphere. The furnace 10 may be sized for residential central heating or for space heating.
The furnace 10 has a generally box-like shape of rectangular cross section including a top wall 24, a front wall 26, opposed sidewalls 28 and 30, a rear wall 32 and a bottom wall 34. As explained below, various of the furnace walls cooperate in fluid tight engagement to enclose and separate furnace components and gaseous flows as well as to define the serpentine flow path for the combustion products. The blower assembly 12 is of conventional design and includes a blower 36 contained within a blower chamber 37 defined by the lower furnace wall 34 and an adjacent intermediate furnace wall 38 together with the surrounding furnace walls 26-32. The blower 36 is arranged to circulate air to be heated to the radiative heat transfer section 18 via an opening 38a in the wall 38. The air to be heated may be drawn into the chamber 37 through a louver covered opening 37a in the front wall 26 which communicates with the space to be heated.
The radiative heat transfer section 18 contains six firetubes 40 which are equally spaced apart parallel to one another in a horizontal plane. The radiative section 18 provides a parallelepiped-shaped firetube enclosure having an approximately square base and a height approximately 50% larger than the diameter of the firetubes. In the radiative section 18 of the heat exchanger 16, radiation plays a prominent role in the heat exchange process, whereas heat transfer is effected primarily by convection at the shell-and-tube section.