Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to a heater and
more particularly a heater adapted for incorporation
in an open fire place, either existing or under
construction, to better utilise the heat energy output
from fuels being burnt in the fire-place.
It is known to provide heater units incorporating
combustion chambers, as distinct from open fire-places, for
the burning of fuels and also incorporating means to force air
adjacent the combustion chamber and outwardly of the
unit into the room area to be heated. However, such
units are costly to manufacture and are permanently
situated units and thus costly to install, whilst also
being difficult to maintain and clean.
Portable heating units are also known
which basically comprise a plate member adapted to be
positioned in an open fire-place and adjacent the
fire so as to be heated thereby whilst air is blown
over and/or under the plate to be heated thereby and
thereafter directed into the room area to be heated.
However, such units are generally inefficient and
do not utilise as much as possible of the available
heat.
Furthermore, both the known permanent and
portable heating units discussed above primarily
direct heated air into the area immediately in front
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of the fire-plclce thus not only affectin~ th~ natura]. draw
o~ air into the fire-p]ace and up the chimney to ensure
efficient combustion of the fuel, but much of the heated
air is also drawn back into the fire and up the chirnney
rather than being directed well out into the room area to
be heated.
It is an object of the present invention to provide a
heating unit which will overcome or diminish the problems
with known heating units of the type discussed above.
The present invention envisages a heating unit adapted
to be positioned within an open fire-place, said heating
unit including an upper plate of heat conductive material
and upon which the fuel to be burnt is positioned, passage
means beneath said plate and communicating at one end with
an inlet for air to be heated and at the other end with a
single outlet for heated air, said passage means
incorporating at least one baffle plate directed
substantialLy along at least part of the length of the
passage means in heat conductive relationship with said
uppee pl.ate and servi.ng to divide air flowin~1 through said
passage means into at least two channels an(l to also
restrict- the flow of air, and wherein said single outlet
is positioned to one side of the unit such that heated air
wil.l be directed away from the front of the fire-pLace to
one side thereof such as to not ;ssue into the path of the
natural draw of air to the fire-place but such as to
circul.ate in a single path around the room area to be
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h~atecl an(1 t)ack to the inlc~t for the unit.
~rhe effect of the baffle plate or plates
in dLvlc~ing t}~e air flow into at least two cl~anllels,
whilst at the same time restricting the rate of air
flow,firstly ensures that the air flows adjacent
a greater number of surfaces from which heat is
radiating, that is the surfaces provided by the
upper plate, the walls defining the passage means
and the baffle plate or plates, whilst the restriction
of air flow increases the time for which the air is
being heated. Both these effects together increase the
efficiency of the heating unit.
Preferably air is forced or blown into
the heating unit by a fan situated adjacent the
inlet but sufficiently far enough away from the
fire to ensure a relatively long fan life.
Alternatively, the fan may be positioned adjacent
the outl.et from the heatirlg Ullit to draw air through
the hecltillg urlit ancl direct it out into ~tle room
area to be heated.
Several preerred embodiments of the
inventioll will rlow be described wi.tll refercnce to
the accompanyill~ drawings, in whicll;
Figure 1 i.s a perspective view of a
heater unit in accordance with one of the siml)lest
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forms of the present invention,
Figure 2 is a cross-sectional view
taken along line 2-2 of Figure.l,
Figure 3 is a cross-sectional view taken
along line 3-3 of Figure 2,
Figure 4 is a perspective view of an
alternative heater unit in accordance with the
simplest form of the present invention,
Figure 5 is a perspective view of another
embodiment o~ the present invention in cooperation
with a ducted system, and
Figure 6 is a perspective view of a still
further embodiment of the present invention also in
cooperation with a ducted system.
Referring to Figure 1 of the drawings, one
of the simplest forms of the present invention involves
a heater unit generally indicated as 10 situated within,
and on the hearth of, an open ~ire-place 11, and
comprising a heater box 12 and front and rear upstanding
fire retaining walls 13 and 1~. The front wall 13 has
apertures 15 formed therethrough to allow air to be
drawn through the wall to the fire situated on top
of the heater box.
Referring to Figures 2 and 3 of the drawings,
the heater box 12 comprises a rear wall 16, a front wall
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17, first and second side walls 18 and 19, a top wall
or plate 20, and a bottom wall or base 21. Wall
members 22 are provided within the heater box to
extend between the top wall 20 and the bottom wall
21 to form a passage 23 of serpentine configuration
as shown and extending between an inlet 24 in the
first side wall 18 and an outlet 25 in the front wall
17. As shown, the outlet 25 is positioned toward
one end of the front wall 17 and ad~acent the second
side wall 19. In the three straight sections shown
for the passage 23 a series, in this case three,
baffle plates 26 are provided to sub-divide the passage
into four channels 27. The baffle plates 26 are
formed in heat conductive relationship with the top
wall 20 and extend down to a position short of the
bottom wall 21 to be spaced therefrom by a distance
of in the order of 1/8 of an inch.
Insofar as the wall members 22 defining the
passage 23, and the baffle plates 26, are in heat
conductive relationship with the top wall 20 upon
which the.fire is placed, air forced or drawn through
the passage 23 and sub-divided by the baffle plates
26 passes adjacent a relatively large number of
heat radiating surfaces as provided by the top wall
20, the wall members 22 and the baffle plates 26,
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and thus receives a relatively large amount of the
available heat. Furthermore, insofar as the baffle
plates act to restrict the flow o~ air, the air remains
within the heater box for a relatively long period of
time to gain as much heat as possible before being
directed out into the room area to be heated.
In the embodiment of Figures 1 to 3, air is
forced through the heater box by a fan situated in a fan
housing 28 and through a supply duct 29 connected to the
inlet 24. In this case the fan housing is concealed within
the brickwork surrounding the fire-place and air is drawn
into the fan housing through an inlet vent communicating
with the room area, or opening through an outside wall, or
communicating with a space beneath the floor, or in the
cavity between the outside wall and the brickwork defining
the open fire-place.
Because of the positioning of the outlet 25
air is directed away from the front of the fire-place to
one side thereof so as not to affect the natural draw
through the fire and up the chimney and to also ensure
that heated air is not immediately drawn back into the
fire-place and up the chimney.
The inlet to the fan box is also situated such
that heated air circulates in a path extending into the
room area, around within the area, and back to the inlet.
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With the embodiment of Figure 4, the heating
unit is identical to that of Figures 1 to 3 except
that the fan housing 28 is positioned within the room
area in an exposed position and thus requires no
special installation.
In the embodiment of Figure 5 the heater
box construction is also identical to that of the
previous embodiments, however, in this case, the
fan housing 28' and supply duct 29' are placed
beneath the floor of the room area and draw air
through a duct 30 from one, or more, air intake registers
31 positioned well away from the fire-place.
In the embodiment of Figure 6 the heater
box construction is once again the same as that of the
previous embodiments, however, the outlet is either not
provided in the front wall of the heater box, or is
closed off, and air is instead directed through a
delivery duct 32 to an outlet ~egister 33 positioned well
away from the fire-place, whilst the fan housing
28" and supply duct 29" are positioned beneath
the floor of the room area to draw air from the
space beneath the floor.
In practice the heater box 12 is formed from
steel or cast iron components and measures approximately
32 inches by 18 inches by 4 inches. A two speed fan
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may be utilised delivering, at its highest speed, 100
cubic feet of air per minute. In practice outputs
of up to 30,000 B.T.U. have been obtained and could
be exceeded if preheated air is used such as drawn
from the cavity behind the outside wall and the
brickwork defining the open fire-place.
A fire cover may be provided to be placed
over the fire to retain heat and to regulate the amount
of combustion air drawn into the fire to in effect
convert the heating unit into a slow combustion unit
with lesser fuel consumption. Such a fire cover
eliminates the need for a fire screen when the fire
is unattended, such as late at night through to early
morning, and whilst the fire remains burning the unit
will continue to direct heated air into the room area,
whilst, with correct regulation of the amount of
combustion air and an adequate amount of fuel, the
fire will still be burning in the morning.
