Note: Descriptions are shown in the official language in which they were submitted.
d~37~3
This invention relates generally to fireplace6,
and specifically to a combination fireplace grate and heat
exchanger which supplements and improves the heating charac-
teristics of a conventional fireplace~
A conventional fireplace is a relatively ineffi-
cient means of heating a room. Although heat generated in
the fireplace is radiated into the room, much of the heat
generated in the fireplace is exhausted from the fireplace
through the flue and chimney. Additionally, a substantial
10. portion of the heated air within the room i5 drawn into the
fireplace and exhausted through the fireplace flue and
chimney.
Many structures for improving the heating charac-
teristics of fireplaces are known. Various structures
appear in the following United States Patents:
1,568,816; 1,571,741; 3,190,282; 3,Z40,206; 3,635,211;
3,756,218; 3,86~,595; 3,896,785; 3,901,212; 3,905,351,
3,930,490; 3,930,491; 3,938,496; 3,942,509; 3,945,369;
3,955,553; 3,965,886; 3,995,611; 4,008,703; 4,008,704;
20. 4,008,706; ~,008,707; 4,010,729; 4,018,208; 4,018,209;
4,018,210; 4,049,196; 4,050,441.
It is an object of the present invention to pro-
vide an improved fireplace heat exchanger structure.
According to the present invention, a fireplace
heat exchanger grate comprises an inlet manifold, an outlet
manifold and a plurality of heat exchange conduits providing
communication between the inlet and outlet manifolds. The
heat exchanger further includes a first duct section tele-
scopically connected to the inlet manifold and in open
30. communication therewith, and a second duct section tele-
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scopicall~ connected to the outlet manifold and in open
communication therewith. An elongated connector duct sec-
tion is provided which extends generally horizontally across
the open front of the fireplace. The connector auct section
is in open communication with both the first and second duct
sections. The connector duct section is provided with an
internal baffle between its connections to the irst and
second duct sections. A blower is connected to the connec-
; tor duc-t section at a first end thereof to move air through
10. the first end, the first duct section, ~he inlet manifold,
the heat exchange conduits, the outlet manifold, and the
second duct section, and to the downstream side of the
baffle in the connector duct section. An outlet vent is
provided in the downstream side of the connector duct sec-
tion to exhaust warmed air into the room.
The telescopic connections of the first duct
section to the inlet manifold and the second duct section
to the outlet manifold permit adjustment to be-made of the
distance between the connector duct section and ~he grate
20. to accommodate fireplaces having varying depths. The con-
nector duct section is removably attached to the first and
second duct sections to permit placement of the first end
o the connector duct section on either the right- or left-
hand side of the firepIace opening. Also for this reason,
the blower is removably attached to the first end, and the
blower housing is designed to permit the blower housing to
- be positioned in either of two orientations relativ~ to
the connector duct section.
The invention may best be understood b~ referring
30. to the following description and accompanying drawings which
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illustrate the invention. In the drawings:
Fig. 1 is an isometric view of a fireplace heat
exchanger constructed according to the present invention,
a fireplace screen being shown ragmentarily, a fireplace
opening being illustrated in broken lines in ~onnection
therewith;
Fig. 2 is a horizontal sectional view, partly
broken away, of the fireplace heat exchanger of Fig. 1,
taken generally along section lines 2-2 thereof;
10. Fig. 3 is a sectional view, partly broken away,
of the fireplace heat exchanger structure of Figs. 1-2,
taken generally along section lines 3-3 of Fig. 2; and
Fig. 4 is a detail, partly broken away, o an
alternative arrangement of various components of the fire-
place heat exchanger o Figs. 1-3.
Referring now to Figs. 1-3, the apparatus 10 in-
cludes a grate 12, for insertion into a fireplace 11 through
a fireplace opening 15. The grate is provided by an inlet
manifold 14 and an outlet manifold 16 coupled together by
20. a plurality of heat exchange conduits 18. Each of inlet and
outlet manifolds 14, 16 is generally pentagonal prism-shaped
including an outwardly and rearwardly facing wall 17, 19,
respectively, to conform to the conventional shape of a
fireplace. Each of inlet and outlet manifolds 14, 16 is
provided with an inwardly facing wall 20 having a plurality
of horizontally spaced openings 21, best il~ustrated in
Figs. 2-3. The heat exchange conduits 18, which are il-
lustratively tubes or pipes, extend between inlet and outlet
~` manifolds 14, 16, respectively, and are in open communica-
30. tion with the interiors of manifolds 14, 16 through openings
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21. The ends of conduits 18 are secured in openings 21 by
any suitable means, e.g., welding.
Grate 12 further includes a member 22 having
; vertical end standards 23 attached, illustratively by
sheet metal screws,to the front faces 24 of inlet and outlet
manifolds 14, 16, and to the rear faces 26 of inlet and out-
let manifolds 14, 16. Grate member 22 fur~her includes two
somewhat U-shaped members 28 which extend beneath the heat
- exchange conduits 18 generally parallel to one another and ~ -
10. are attached to the undersides of one or more of conduits
18 ~y any suitable means, e.g., welds or screws. Front and
rear horizontal cross members 30 are provided on grate mem-
ber 22, the members 30 being attached to the forward and
rearward vertically upper extents of vertical standards 23
and U-shaped members 28, illustratively by welding. It will -
be appreciated that this somewhat "cradle" shaped grate 12
maintains the fuel in position in the fireplace 11 for
burning (see Fig. 3).
The apparatus 10 further includes a first duct
20. section 32 which is telescopically connected at 34 to the
front face 24 of inlet maniold 14. The telescopic connec-
tion 34 is achieved by a bracket 36 which is welded or
otherwise secured to the face 24 of inlet manifold 14 above
a generally rectangular openîng 38 at the bottom of face
24. Rectangular opening 38 is sized slidably to receive the
generally rectangular cross section first duct section 32.
A set screw 40 is provided in a threaded aperture 41 on
bracket 36. A series of reliefs or indentations 42 is
provided in the horizontal top wall 44 of first duct section
30. 32. Duct section 32 is oriented in opening 38 such that one
of the reliefs 42 underl.ies the end of set screw 40~ The
set screw 40 can then be tightened into the threaded aper- -
ture 41 to capture duct section 32 in a selected orienta-
tion with respect to inlet manifold 14.
A second duct section 52, which is ~lso genexally
rectangular in cross section, is telescopically connected,
as at 54~ to the front face 24 of outlet manifold 16. This
telescopic connection is achieved by bracket 56 on the wall
24 of outlet manifold 16, the ~xacket 56 overlylng a rec-
10. tangular opening 58 at the bottom of face 24 in outlet
manifold 16. Opening 5g is sized slidably to receive the
second duct section 52. A set screw 60 is provided in a
threaded aperture 61 on bracket 56. The set screw cooper-
ates with a series of reliefs 62 spaced along the length of
top wall 64 of duct section 52 to permit the second duct
section 52 to be telescoped into outlet manifold 16 to any
desired position, and retained in that position by tighten-
ing of set screw 60 into one of reliefs 62.
A generally rectangular cross-section connector
20. duct section 70 has a first end 72 and a second end 74. The
connector duct section 70 extends generally horizontally
across the opening lS of fireplace 11. The second end 74 of
connector duct section 70 is closed by a~ end cap 75.
Connector duct section 70 includes an opening 76 providing
open communication with duct section 32 and an opening 78
providing open communication with duct section 52. Openings
76, 78 are formed in the generally vertically extending
rearwardly facing wall 79 of duct section 70. Each of
openings 76, 78 is surrounded, at least partially, by a lip
30. 82 formed by bending part o~ the sheet metal axound each of
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openings 76, 78 outwardly at right angles to wall 79. The
duct sections 32, 52 are removably attached to duct section
70 by sheet' metal screws'84 threaded through mated holes in
the forward ends of duct sections 32, 52 and lips 82. The
removable connection of duct section '70 to duct sections 32,
52 permits connector duct section 70 to be positioned in two
relative orientations with respect to duct sections 32, 52
and the grate 12~ That is, duct section 70 may be posi-
tioned with its first end 72 on either the right-hand side
10. of fireplace opening 15 (as illustrated in Figs. 1-3), or on
the left-hand side of fireplace opening 15 (as illustrated
in Fig. 4). Outlet or exhaust vents 90 are provided in the
front vertical side wall 92 oE connector duct section 70.
Internally, connector duct section 70 is divided into an
upstream portion 94 and a downstream portion 96 by an
internal baffle 100. The baffle 100 is secured in con-
nector duct section 70 by any suitable means, e.g., welding
and prevents direct communication from the upstream side 94
to the downstream side 96. As best illustrated in Fig. 2,
20. baffle 100 is curved to promote air flow from the first end
72 through opening 76 and into the first duct section 32.
Air then circulates through the inlet manifold 14, the heat
exchange conduits 18, the outlet manifold 16 and second duct
section 52 to the downstream side 96 of connector duct
" section 70 from which it is exhausted through the outlet
vents 90. It will be appreciated that when fuel is burning
in the fireplace 11, the circulating air will be heated and
will be exhausted through vents 90 into the room to provide
additional heat.
; 30 To promote this additional heat:ing, a blower 102
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is removably attached to end 72 of connector duct section ,
70. Blower 102 includes' a hbusing 104 formed from two
substantially identical right' angle slections 106, each of
which provides two adjacent sides 107 of housing lU4. The
two right angle sections 106, which dlesirably are construct-
ed from sheet metal, are'astened together at their diago-
nally opposite'corners to form a sturdy cube structure. One
of the remaining faces of the s~ructure is closed by a sheet
metal back 110 with openings 112, 114 for a power cord 116
10. and a control switch 118, respectively. Space 120 is pro-
vided between the back 110 and one of the right angle members
106 to permit air to enter housing 104. Housing 104 also
includes a front face 122 closing the side thereof opposite
back 110. Front face 122 is generally rectangular and is
provided with a single opening 124 (illustrated in broken
lines in Fig. 1) a'djacent one corner thereof. The opening
124 is rectangular, but the sides of opening 124 make
approximately 45 angles with the edges of front face 122.
Thus, opening 124 has a somewhat diamond-shaped appearance
20. when housing 104 is resting on one of the sides 107 thereof.
A sheet metal transition duct section 126 connects
housing 104 to end 72 of connector duct section 70. As best
illustrated in Fig. 1, transition duct section 126 is gen-
erally trapezoidal in longitudinal section, and has a first
end 128 at which it is connected to housing 104. End 128
is generally square in cross section. Duct section 126 has
a second end 130, at which it is connected to end 72 of
~ connector duct section 70. End 130 has a rectangular cross
; section slightly smaller than end 72 to fit into end 72.
30- Each side of end 128 has a length slightly greater than the
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diagonal dimension of opening 124 in housing 104 r SO that
opening 124 will be entirely covered by transition duct
section 126. A flange 140 is provided on end 128 and a
sheet metal scre~ 142 is threaded through holes in flange
140 and front face 122 of housing 104 to attach the transi-
tion duct section 126 to housing 104. Two screw holes are
provided in the front face 122 for the sh~et metal screw
142, one for each orientation of the transition duct section
126 with respect to front face 122. In one orientation,
10. illustrated in Figs. 1-3, housing 104 rests on a side 144
thereof. In the other orientation, illustrated in Fig. 4,
housing 104 rests on a side 146 thereof. Sheet metal
screws 150 are provided or attaching the other end of
transition duct section 126 to end 72 of connector duct
section 70.
The connector duct section 70 has a low profile
and is arranged at the bottom of the fireplace opening 15 to
minimize its interference with the fireplace draft charac-
teristics. Further, the top surface of duct section 70 is
20. flat so that a fireplace screen may rest on top of it. ~his
makes installation of the instant heat exchanger system
simpler than many prior art systems, since the screen does
- not have to be altered to install this system. Alterna-
tively, the heat exchanger system of this invention can be
incorporated into one of the popular glass-and-metal fire-
place screen closure structures.
