WOOD-BURNING STOVE WITH INTERNAL BAFFLES FOR INCREASED BURN TIMES

POELE A BOIS AYANT DES CHICANES INTERNES POUR DES DUREES DE COMBUSTION ACCRUES

English Abstract

Abstract A wood-burning stove includes a first baffle spaced apart from the stove's front wall and extending from the stove's floor towards its ceiling to a height in a range of (0.65-0.75) of the stove's internal height. An air intake chamber is defined between the stove's front wall and first baffle. A firebox is defined between the first baffle and the stove's back wall. A second baffle is coupled to the stove's back wall at a position thereon below the stove's flue port. The second baffle extends from the back wall towards the first baffle to a second baffle depth of (0.7-0.85) of the stove's firebox depth. The second baffle terminates at an outboard edge that is spaced apart from the stove's ceiling to define a flow area in a range of 0.5-1.0 times a cross-sectional area of the flue port. CA 3062464 2019-11-22

French Abstract

Abrégé Un poêle à bois comprend un premier déflecteur qui est séparé du mur avant du poêle et qui sétend entre le plancher et le plafond de ce dernier pour atteindre une hauteur égale à (entre 65 % et 75 %) de la hauteur intérieure du poêle. La chambre de prise dair est définie entre le mur avant du poêle et le premier déflecteur. Un foyer est défini entre le premier déflecteur et le mur arrière du poêle. Un deuxième déflecteur est attaché au mur arrière du foyer dans une position sous le port du conduit de fumée. Le deuxième déflecteur sétend entre le mur arrière et le premier déflecteur pour atteindre une longueur égale à (entre 70 % et 85 %) de la profondeur du foyer. Le deuxième déflecteur se termine à une extrémité extérieure séparée du plafond du poêle de manière à définir une zone de flux dont la longueur de la coupe transversale est entre la moitié et la totalité de la longueur de la coupe transversale du port du conduit de fumée. CA 3062464 2019-11-22

Claims

Claims:
1. A wood-burning stove, comprising:
a fireproof container having a floor, a ceiling, a front wall, a back wall
opposing said front
wall, and two opposing side walls spanning from said front wall to said back
wall wherein said
front wall, said back wall, and said two opposing side walls span between and
are coupled to
said floor and said ceiling, and wherein an internal height H of said
container is defined by a
distance between said floor and said ceiling, said container having an air
intake port in a lower
portion of said front wall and having a flue port in one of said ceiling and
an upper portion of said
back wall;
a first baffle disposed in said container and spaced apart from said front
wall, said first
baffle spanning between and coupled to said two opposing side walls, said
first baffle extending
from said floor towards said ceiling to a first baffle top at a first baffle
height in a range of (0.65)H
to (0.75)H, wherein an air intake chamber is defined in said container between
said front wall
and said first baffle and a firebox is defined between said first baffle and
said back wall, said air
intake chamber adapted to receive combustion air therein from an environment
outside of said
container, wherein a top of said firebox coincides with said first baffle top,
wherein said
combustion air for said firebox flows from said air intake chamber over said
first baffle top before
passing into said top of said firebox, and wherein an internal depth D of said
firebox is defined
by a distance between said first baffle and said back wall; and
a second baffle disposed in said container, said second baffle spanning
between and
coupled to said two opposing side walls, said second baffle coupled to said
back wall at a
position thereon below said flue port, said second baffle extending from said
back wall towards
said first baffle to a second baffle depth of (0.7)D to (0.85)D, said second
baffle terminating at
an outboard edge spaced apart from said ceiling wherein a flow area between
said outboard
edge and said ceiling is in a range of 0.5-1.0 times a cross-sectional area of
said flue port.
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2. A wood-burning stove as in claim 1, further comprising a baffle extension
for adjusting said
first baffle height.
3. A wood-burning stove as in claim 1, further comprising a door opening in
said front wall
wherein a direct passageway from said door opening to said firebox is defined
between said first
baffle and said outboard edge of said second baffle.
4. A wood-burning stove as in claim 3, further comprising a door coupled to
said front wall for
closing said door opening and for permitting access to said door opening.
5. A wood-burning stove as in claim 1, wherein said container, said first
baffle, and said second
baffle comprise weldable materials.
6. A wood-burning stove as in claim 1, wherein said first baffle is spaced
apart from said front
wall by a distance in a range of 2-4 inches.
7. A wood-burning stove as in claim 1, wherein said air intake port is
adjacent to said floor.
8. A wood-burning stove as in claim 1, wherein said air intake port is
adjustable in terms of an
amount of air that can pass there through.
9. A wood-burning stove, comprising:
a fireproof container having a floor, a ceiling, a front wall, a back wall
opposing said front
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wall, and two opposing side walls spanning from said front wall to said back
wall wherein said
front wall, said back wall, and said two opposing side walls span between and
are coupled to
said floor and said ceiling, and wherein an internal height H of said
container is defined by a
distance between said floor and said ceiling, said container having an air
intake port in a lower
portion of said front wall and having a flue port in one of said ceiling and
an upper portion of said
back wall;
said front wall including a vertical wall portion perpendicular to said floor
and an angled
wall portion extending from said vertical wall portion to said ceiling, said
angled wall portion at a
first obtuse angle relative to said vertical wall portion and at a second
obtuse angle relative to
said ceiling;
a first baffle disposed in said container and spaced apart from said front
wall, said first
baffle spanning between and coupled to said two opposing side walls, said
first baffle extending
from said floor towards said ceiling to a first baffle top at a first baffle
height in a range of (0.65)H
to (0.75)H, wherein an air intake chamber is defined in said container between
said front wall
and said first baffle and a firebox is defined between said first baffle and
said back wall, said air
intake chamber adapted to receive combustion air therein from an environment
outside of said
container, wherein a top of said firebox coincides with said first baffle top,
wherein said
combustion air for said firebox flows from said air intake chamber over said
first baffle top before
passing into said top of said firebox, and wherein an internal depth D of said
firebox is defined
by a distance between said first baffle and said back wall;
a second baffle disposed in said container, said second baffle spanning
between and
coupled to said two opposing side walls, said second baffle coupled to said
back wall at a
position thereon below said flue port, said second baffle extending from said
back wall towards
said first baffle to a second baffle depth of (0.7)D to (0.85)D, said second
baffle terminating at
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an outboard edge spaced apart from said ceiling wherein a flow area between
said outboard
edge and said ceiling is in a range of 0.5-1.0 times a cross-sectional area of
said flue port; and
a door opening in said angled wall portion wherein a direct passageway from
said door
opening to said firebox is defined between said first baffle and said outboard
edge of said
second baffle.
10. A wood-burning stove as in claim 9, further comprising a baffle extension
coupled to said
first baffle for adjusting said first baffle height.
11. A wood-burning stove as in claim 9, further comprising a door coupled to
said angled wall
portion for closing said door opening and for permitting access to said door
opening.
12. A wood-burning stove as in claim 9, wherein said container, said first
baffle, and said
second baffle comprise weldable materials.
13. A wood-burning stove as in claim 9, wherein said first baffle is spaced
apart from said
vertical wall portion by a distance in a range of 2-4 inches.
14. A wood-burning stove as in claim 9, wherein said air intake port is
adjacent to said floor.
15. A wood-burning stove as in claim 9, wherein said air intake port is
adjustable in terms of an
amount of air that can pass there through.
16. A wood-burning stove, comprising:
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a fireproof container having a floor, a ceiling, a front wall, a back wall
opposing said front
wall, and two opposing side walls spanning from said front wall to said back
wall wherein said
front wall, said back wall, and said two opposing side walls span between and
are coupled to
said floor and said ceiling, and wherein an internal height H of said
container is defined by a
distance between said floor and said ceiling, said container having an air
intake port in a lower
portion of said front wall and having a flue port in one of said ceiling and
an upper portion of said
back wall;
a first baffle disposed in said container and spaced apart from said front
wall, said first
baffle spanning between and coupled to said two opposing side walls, said
first baffle extending
from said floor towards said ceiling to a first baffle top at a first baffle
height in a range of (0.65)H
to (0.75)H, wherein an air intake chamber is defined in said container between
said front wall
and said first baffle and a firebox is defined between said first baffle and
said back wall, said air
intake chamber adapted to receive combustion air therein from an environment
outside of said
container, wherein a top of said firebox coincides with said first baffle top,
wherein said
combustion air for said firebox flows from said air intake chamber over said
first baffle top before
passing into said top of said firebox, and wherein an internal depth D of said
firebox is defined
by a distance between said first baffle and said back wall;
a baffle extension coupled to said first baffle for adjusting said first
baffle height;
a second baffle disposed in said container, said second baffle spanning
between and
coupled to said two opposing side walls, said second baffle coupled to said
back wall at a
position thereon below said flue port, said second baffle extending from said
back wall towards
said first baffle to a second baffle depth of (0.7)D to (0.85)D, said second
baffle terminating at
an outboard edge spaced apart from said ceiling wherein a flow area between
said outboard
edge and said ceiling is in a range of 0.5-1.0 times a cross-sectional area of
said flue port; and
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a door opening in said front wall wherein a direct passageway from said door
opening to
said firebox is defined between said first baffle and said outboard edge of
said second baffle.
17. A wood-burning stove as in claim 16, further comprising a door coupled to
said front wall for
closing said door opening and for permitting access to said door opening.
18. A wood-burning stove as in claim 16, wherein said container, said first
baffle, and said
second baffle comprise weldable materials.
19. A wood-burning stove as in claim 16, wherein said first baffle is spaced
apart from said front
wall by a distance in a range of 2-4 inches.
20. A wood-burning stove as in claim 16, wherein said air intake port is
adjacent to said floor.
21. A wood-burning stove as in claim 16, wherein said air intake port is
adjustable in terms of
an amount of air that can pass there through.
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Description

WOOD-BURNING STOVE WITH INTERNAL BAFFLES
FOR INCREASED BURN TIMES
Field of the Invention
[0001] The invention relates generally to wood-burning stoves, and
more particularly to
a wood-burning stove having internal baffles for increasing the length of time
that a fire burns
while decreasing the outside temperature of the stove to levels that are safe
for human contact.
Background of the Invention
[0002] Wood-burning stoves have been used for cooking and heating for
years.
Typically, the stove is positioned inside a home's living area. For purposes
of heating, a fire
in a wood-burning stove must be stoked periodically in order to maintain heat
output.
Shortly after a fire is stoked, heat generated by the stove spikes as the
fire's intensity
increases. During such a spike, the wood burns rapidly and the stove's outer
surfaces
reach temperatures that can burn one's skin or clothing. After the wood has
burned
sufficiently, the stove's heat generation experiences a drop off in production
during which a
home's indoor temperature can drop rather quickly depending on outside
temperatures.
This burn cycle of heat spike and cooling reduces the effectiveness and
desirability of wood-
burning stoves. For example, when the cooling cycle occurs when a home's
occupants are
not home or asleep, the occupants come home to or wake up in a cold
environment.
Further, the heat spikes that occur shortly after a fire is stoked can cause
safety issues for a
home's occupants as a stove's outer temperature increases to skin-burning
levels.
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Summary of the Invention
[0003] Accordingly it is an object of the present invention to provide
a wood-burning
stove.
[0004] Another object of the present invention is to provide a wood-
burning stove
having improved effective burn times to thereby reduce fire stoking
requirements.
[0005] Still another object of the present invention is to provide a
wood-burning
stove that generates a steady level of heat.
[0006] Yet another object of the present invention is to provide a
wood-burning stove
whose heat generation is at a level suitable for use as home heat but low
enough that the
stove is safe for human touch throughout the stove's burn cycle.
[0007] Other objects and advantages of the present invention will
become more
obvious hereinafter in the specification and drawings.
[0008] In accordance with the present invention, a wood-burning stove
includes a
fireproof container having a floor, a ceiling, a front wall, a back wall
opposing the front wall, and
two opposing side walls spanning from the front wall to the back wall. The
front wall, back wall,
and two opposing side walls span between and are coupled to the floor and
ceiling. The
internal height H of the container is defined by a distance between the floor
and the ceiling.
The container has an air intake port at a lower portion of its front wall, and
has a flue port in one
of its ceiling and upper portion of its back wall. A first baffle disposed in
the container and
spaced apart from the front wall thereof spans between and is coupled to the
two opposing
side walls. The first baffle extends from the floor towards the ceiling to a
first baffle height in a
range of (0.65)H to (0.75)H. An air intake chamber is defined in the container
between its front
wall and first baffle, and a firebox is defined between the first baffle and
the container's back
wall. An internal depth D of the firebox is defined by a distance between the
first baffle and the
container's back wall. A second baffle disposed in the container spans between
and is coupled
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to the container's two opposing side walls. The second baffle is also coupled
to the container's
back wall at a position thereon below the container's flue port. The second
baffle extends from
the back wall towards the first baffle to a second baffle depth of (0.7)D to
(0.85)D. The second
baffle terminates at an outboard edge that is spaced apart from the
container's ceiling to define
a flow area between the outboard edge and ceiling that is in a range of 0.5-
1.0 times a cross-
sectional area of the flue port.
Brief Description of the Drawings
[0009] Other objects, features and advantages of the present invention
will become
apparent upon reference to the following description of the preferred
embodiments and to the
drawings, wherein corresponding reference characters indicate corresponding
parts throughout
the several views of the drawings and wherein:
[0010] FIG. 1 is a perspective view of a wood-burning stove having its
flue port in a
back wall thereof in accordance with an embodiment of the present invention;
[0011] FIG. 2 is a perspective view of a wood-burning stove having its
flue port in a
ceiling thereof in accordance with another embodiment of the present
invention;
[0012] FIG. 3 is a front-to-back cross-sectional view of the wood-
burning stove
shown in FIG. 1 in accordance with an embodiment of the present invention;
[0013] FIG. 4 is a front-to-back cross-sectional view of the wood-
burning stove in
FIG. 2 in accordance with another embodiment of the present invention;
[0014] FIG. 5 is a side-to-side cross-sectional view of a wood-burning
stove having
an air intake baffle chamber wall in accordance with another embodiment of the
present
invention;
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,
[0015] FIG. 6 is a side-to-side cross-sectional view of a
wood-burning stove having
an air intake chamber's baffle wall with a baffle extension in accordance with
still another
embodiment of the present invention;
[0016] FIG. 7 is a side view of a baffle extension in
accordance with an embodiment
of the present invention; and
[0017] FIG. 8 is a side-to-side cross-sectional view of the
wood-burning stove taken
along line 8-8 in FIG. 3 illustrating the smoke chamber's baffle in accordance
with an
embodiment of the present invention.
Detailed Description of the Invention
[0018] Referring now to the drawings and more particularly to
FIGs. 1 and 2, two
embodiments of wood-burning stoves are illustrated in perspective views
thereof and are
referenced generally by numerals 10 and 100, respectively. Stove 10 has its
flue port in a
back wall thereof such that a flue 200 is attached to the back wall of stove
10. Stove 100
has its flue port in a ceiling thereof such that a flue 200 is attached to the
ceiling of stove
100. Both stove 10 and stove 100 incorporate features unique to the present
invention that
increase burn times to reduce fire stoking requirements, provide for the
generation of a
steady level of heat, and maintain stove surface temperatures at levels that
are safe for
human touch. The unique features of stove 10 and stove 100 will be explained
with
reference to the front-to-back cross-sectional views thereof presented in
FIGs. 3 and 4,
respectively.
[0019] With respect to stove 10, simultaneous reference is
made to FIGs. 1 and 3
where the stove is essentially a fireproof container having a floor 12, a
ceiling 14, a front wall
16, a back wall 18, and opposing side walls 20 and 22. Each of walls 16, 18,
20 and 22 is
coupled to adjacent ones of the walls and to floor 12 and ceiling 14. The
internal height of
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stove 10 between floor 12 and ceiling 14 is defined as H. Materials used for
stove 10
generally comprise weldable materials such as heavy gauge steel, cast iron,
etc.
[0020] Stove 10 also includes an air intake port 24 and a flue port
28. Air intake port
24 is a hole passing through a lower portion of front wall 16. For example,
air intake port 24
can be immediately adjacent to floor 12. A door 26 (e.g., a sliding door as
shown, a rotating
door, etc.) can be coupled to front wall 16 to allow a user to adjust the pass-
through size of
air intake port 24 as would be understood in the art. Flue port 28 is a hole
passing through
an upper portion of back wall 18 in proximity to ceiling 14 as would be
understood in the art.
The open area of flue port 28 is defined as AF.
[0021] Disposed within stove 10 are two baffles 30 and 40. Each of
baffles 30 and
40 spans the width of stove 10 and is coupled to opposing side walls 20 and
22. Each of
baffles 30 and 40 can be made from the same fireproof materials used for the
floor, ceiling
and walls of stove 10. As will be explained further below, baffles 30 and 40
are positioned
and configured to control a fire's flow of combustion-air and post-combustion
air/smoke to
increase a fire's burn time, while simultaneously reducing the fire's
intensity throughout its
burn cycle in order to reduce the stove's surface temperature.
[0022] Baffle 30 is also coupled (e.g., welded) to floor 12 and is
spaced apart from
the portion of front wall 16 where air intake port 24 is located such that an
air intake
chamber (referenced by dashed-line box 32) is defined in stove 10 between
front wall 16
and baffle 30. Baffle 30 extends from floor 12 to a height H30 that is in a
range of (0.65)H to
(0.75)H. The space between front wall 16 and baffle 30 is typically 2-4
inches. The region
in stove 10 between baffle 30 and back wall 18 defines a firebox as referenced
by dashed-
line box 34. Wood (not shown for purpose of clarity) would be placed in and
burned in
firebox 34. The internal depth of firebox 34 between baffle 30 and back wall
18 is defined as
D.
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[0023] Baffle 40 is also coupled (e.g., welded) to back wall 18 at a
position thereon
below flue port 28. Baffle 40 extends from back wall 18 towards baffle 30 and
terminates at
an outboard edge 42. Baffle 40 spans a distance ID40 that is in a range of
(0.7)D to (0.85)D.
As a result, outboard edge 42 of baffle 40 is positioned over firebox 34.
Outboard edge 42
is spaced-apart from ceiling 14 by a gap 44 that is also shown in FIG. 8.
Baffle 40 is
configured such that the flow area defined by gap 44 is in a range of (0.5)AF
to (1.0)AF
where AF is the area of flue port 28. Baffle 40 can be configured in a variety
of ways to
satisfy the above-noted constraints. For example, in the illustrated
embodiment, baffle 40
can be made from a single sheet of material bent at 40A to improve the
rigidity of baffle 40.
The angle a that baffle 40 makes with back wall 18 can be acute (as shown) or
90 without
departing from the scope of the present invention.
[0024] The above-noted constraints regarding baffles 30 and 40 apply
equally as
well to stove 100 having a flue port defined in its ceiling. Accordingly,
common reference
numerals are used for the elements of stove 100 that are common to stove 10.
In this
embodiment, baffle 40 is perpendicular to back wall 18.
[0025] Although not a requirement of the present invention, front wall
16 can include
a lower vertical portion 16A and an upper angled portion 16B to facilitate
insertion of wood.
More specifically, angled portion 16B forms an obtuse angle p. with vertical
portion 16A and
an obtuse angle 4) with ceiling 14. An opening 50 is defined through angled
portion 16B
such that a direct passageway from opening 50 to firebox 34 and between the
top of baffle
30 and the bottom of baffle 40 is defined as indicated by the region between
dashed-lines
52. A door 54 can be coupled to angled portion 16B by hinges 56 such that
opening 50 can
be closed off or accessed as needed. Door 54 can be solid and opaque, or can
include a
window (e.g., a tempered glass window) to provide visibility into firebox 34
without departing
from the scope of the present invention.
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[0026] Baffle 30 can terminate at its height H30 as described above.
However, the
present invention is not so limited. For example, FIG. 5 illustrates a baffle
wall 60 that spans
the entire internal width between side walls 20 and 22, and extends to ceiling
14. All edges
of baffle 60 are coupled (e.g., welded) to the side walls, floor, and ceiling.
As such, baffle
wall 60 provides additional rigidity for the stove. Baffle wall 60 includes an
opening 62, the
lower edge 64 of which is set at a height falling within the above described
range of (0.65)H
to (0.75)H. Opening 62 defines a passageway for air to enter the stove's
firebox 34 from the
stove's air intake chamber 32.
[0027] A stove in accordance with the present invention can be adapted
to have its
air intake chamber's baffle be adjustable in height. For example, FIG. 6
illustrates the
above-described baffle 30 with an extension plate 36 coupled thereto to
increase the height
of baffle 30 to H36 where H36 would still satisfy the constraints described
previously herein for
H30. Extension plate 36 can include a hook 38 (FIG. 7) to facilitate the
hanging of extension
plate 36 on the top of baffle 30. The position of hook 38 could be adjustable
to allow for the
adjustment of height H36. The same type of extension plate could be used with
baffle wall
60. An adjustment mechanism (not shown) could also be made accessible from
outside of
the stove to allow a user to adjust the height of baffle 30 without reaching
into the stove.
[0028] In operation, with burning wood (not shown) in the stove's
firebox 34, ambient
air is drawn into air intake port 24. The air flows up in chamber 32, over the
top of baffle 30,
and then down to the burning wood in firebox 34. The post-combustion air/smoke
rises up
to baffle 40 and flows there along towards baffle 30 before passing through
gap 44 on its
way to flue port 28. The combination of baffles 30 and 40 creates a tortuous
flow path that
provides air for combustion from above a fire in firebox 34 thereby slowing
the burn process
and reducing the heat transferred to the surface of a stove. In tests of
stoves made from 12
gauge steel and in accordance with features and constraints described herein,
burn times in
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excess of 12 hours have been achieved where outside stove temperatures have
remained
at temperatures that are sufficient to provide heat to a dwelling while
remaining safe for
human touch. Thus, the stoves of the present invention provide long-term, even
heating at
safe-to-touch stove temperatures.
[0029] Although the invention has been described relative to a
specific embodiment
thereof, there are numerous variations and modifications that will be readily
apparent to those
skilled in the art in light of the above teachings. It is therefore to be
understood that, within the
scope of the appended claims, the invention may be practiced other than as
specifically
described.
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Representative Drawing