Note: Descriptions are shown in the official language in which they were submitted.
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FLAMMABLE FLUID HEATING APPARATUS
This application is divided from Canadian Patent
Application Serial Number 2,186,579, filed September 26, 1996.
Field of the Invention
This invention relates a flammable fluid fuelled heaters
and, in particular, although not necessarily solely, gas
fuelled heaters.
Description of the Prior Art
Traditional flammable fluid fuelled heaters such as gas
fuelled heaters comprise a combustion chamber into which the
flammable fluid is supplied and may be provided with an
exhaust into the room into which the heater is housed. Such
flueless units may be provided with catalytic converters
forming a secondary combustion chamber above the primary
combustion chamber to reduce the emissions in the exhaust.
However, in trying to provide such units with an open front
wall to provide an unobstructed view of the flames in
accordance with a conventional fireplace, some difficulties
might arise in minimising the size of that catalytic converter
due to the large open front area for the drawing of air into
the primary combustion unit increasing the overall throughput
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of the heater. A catalytic converter of reduced size causes
an obstruction to the flow of air through the heater and this
may lead to spilling of emissions directly from the primary
combustion out through the open front of the unit and into the
room into which the unit is housed. This can cause problems
with such emissions reaching levels that are either unsafe or
at least outside regulatory guidelines.
Another aspect of traditional fireplaces is attempts to
provide a realistic artificial log assembly in the combustion
chamber. There may be a preference for a primary combustion
chamber and associated artificial log assembly which attempts
to provide a visually larger fire than is physically present
so that the overall size of the heater unit may be minimised
by still providing a relatively large apparent fire area.
Such traditional technology has included the provision of a
mirror behind the artificial log assembly and primary
combustion chamber. However, the reflected image in the
mirror does not always provide a realistic appearance if there
is a visually apparent division between the real image and the
reflected image.
The present invention provides a flammable fluid fuelled
heater which may overcome or minimise any one or more of these
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disadvantages or at least provide the public with a useful
choice.
Accordingly, in a first aspect, the present invention
provides a flammable fluid fuelled heater comprising: a
primary combustion chamber; a flammable fluid fuelled supply
to said primary combustion chamber to upon combustion, provide
a substantial portion of a yellow flame and generate products
of combustion; an opening formed on the primary combustion
chamber for exhausting the products of combustion; an
artificial log assembly provided in said primary combustion
chamber; at least one reflective surface provided on at least
one side of said primary combustion chamber to provide a
reflected view of said substantially yellow flame and
artificial log assembly; and wherein said artificial log
assembly provides at least one artificial log abutting said
reflective surface, said artificial log having a longitudinal
axis substantially parallel to said reflective surface and
having a longitudinal upper edge abutting said reflective
surface such that the artificial log and the apparent
reflection of said log creates the appearance of a full round
log.
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The present invention also provides a flammable fluid
fuelled heater comprising: a primary combustion chamber;
a flammable fluid fuelled supply to said primary combustion
chamber to upon combustion, provide a substantial portion of a
yellow flame and generate products of combustion; an opening
formed on the primary combustion chamber for exhausting the
products of combustion; an artificial log assembly provided in
said primary combustion chamber; at least one reflective
surface provided on at least one side of said primary
combustion chamber to provide a reflected view of said
substantially yellow flame and artificial log assembly; and
wherein said artificial log assembly provides at least one
artificial log abutting said reflective surface and having a
longitudinal axis substantially transverse to the plane of
said reflective surface.
Further aspects of this invention will become apparent to
those skilled in the art upon reading the following
description.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the
following drawings in which:
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Figure 1 shows a cross-sectional view through one
possible embodiment of the apparatus; and
Figure 2 shows a front elevational view of the apparatus
of Figure 1.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Preferred forms of the invention may be seen with
reference to the figures in which a flammable fluid fuelled
heater 1 having a primary combustion chamber 2 is provided.
The primary combustion chamber is provided with a flammable
fluid fuel supply 3 to provide a flammable fluid such as
liquidified petroleum gas or compressed natural gas or other
such fuels for combustion in the primary combustion chamber.
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An outer housing 4 may be provided to house the apparatus
and, in at least this preferred form of the invention, the primary
combustion chamber 2 and outer housing 4 are provided with an
opening 5 providing an unobstructed view of a substantial portion
of the primary combustion chamber 2 and, in particular, that
region in which combustion is occurring.
To provide a visually aesthetic fire, the fuel supply through
the inlet 3 and the combustion characteristics within the primary
combustion chamber 2 are such as to provide a flame having a
substantially yellow appearance. To achieve this, the primary
combustion chamber 2 must be depleted of oxygen content and this
requires strict control over the inlet of oxygenated air into the
primary combustion chamber 2 as well as the mixture of the fuel
provided through the inlet 3.
The yellow flame characteristic providing a more
aesthetically pleasing fireplace, also requires some incomplete
combustion of the fuel in the primary combustion chamber. The
emissions from'such aesthetically pleasing flames are higher than
a comparable heater assembly which is configured to burn with a
substantially clean blue flame. Therefore, there is some risk
that spillage of the products of the primary combustion through
the open front 5 may lead to the room in which the heater is
housed, having raised levels of carbon monoxide and carbon
dioxide.
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Although it is perhaps possible to reduce such spillage
through increasing the throughput through the apparatus 1 such
that the large opening 5 into the primary combustion chamber 2 has
sufficient draught to inhibit the exiting of the products of
primary combustion through that opening, such a throughput leads
to difficulty in achieving the yellow flames while still operating
efficiently. further, a large throughput requires a larger
catalytic converter to accommodate the air flow. Also this
increased throughput will have a cooling effect on a catalyst
which increases the difficulty in achieving light off temperature.
The present invention provides an air circulating means 6
which may be of any convenient type to create an airstream or
draught and, in this preferred form. is provided as a fan. The
circulating means 6 is provided to create a stream of air 7 which
projects across the opening 5. Such an airstream both reduces the
effective size of the opening 5 for air inlet which improves the
ability to deplete the oxygen within the primary combustion
chamber as well as inhibiting the spillage of the products of
combustion adjacent the upper edge of the opening 5. This is
particularly the case when the airstream 7 is provided to project
downwardly from an upper edge of the opening S as indicated in
Figure 1.
In addition, this form of the invention also providers a
deflector a running across the airstream to deflect some of the
airstream back into the primary combustion chamber 2 which further
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helps to reduce spillage of products from the primary combustion
as designated by arrow 9.
Again in the preferred form, the heating apparatus 1 may be
provided as a flueless unit as indicated or, a unit in which at
least a portion of the exhaust from the heater is directed into
the room in which the heater 1 is housed. To improve the standard
of those emissions, a secondary combustion chamber 10 which
includes or comprises a catalytic converter may be provided. In
this manner, the products of primary combustion may be drawn
through the catalytic converter 10 and through an exhaust port 11
into the room in which the heater is housed and be relatively low
in uncombusted hydrocarbons such as carbon monoxide and other
pollutants. With the air inlet being provided at least partially
by the open front 5, not only are the products of the primary
combustion chamber further combusted to improve the exhaust
quality but other odours in the room such as cooking odours may be
removed through the catalytic converter 10.
Catalytic'converters for such apparatus are relatively
expensive and, therefore, the size of the catalytic converter
required can become an important factor in providing a cost
efficient heater. The minimisation of the size of the catalytic
. converter will also decrease the throughput capable from the
catalytic converter 10. It is normal in such units for the
catalytic converter 10 to provide the greatest restriction to flow
in the entire apparatus and this tends to increase any potential
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problems with spillage of products directly from the primary
combustion chamber.
In the present invention, an air duct 12 may be provided in
communication with the secondary combustion chamber or catalytic
converter l0 and the exhaust port 1i so as to create an airstream
across the outlet from the secondary combustion chamber 10. The
duct 12 is also in communication with the air circulating means 6
to create the airstream and the flow of this airstream across the
exit from the catalytic converter and provides the draft through
the catalytic converter to improve overall throughput. Not only
may such an arrangement improve the performance of the catalytic
converter but also reduce the restriction that the converter
provides in the apparatus and therefore decreasing the quantity of
circulating products from the primary combustion as indicated by
arrow 9.
The ducting 12 may also provide a number of other functions
such as providing a fresh cooler airstream within the housing 4 to
reduce the temperatures of the outer panels of the overall
apparatus 1 forming the housing 4. Furthermore, should it be
de9ired, the housing 4 and ducting 12 may be provided with an
inlet 14 for connection to a vent to an area external to the room
in which the heater is housed such as to the outside of a
building. Such an inlet 14 allows ventilation of the room in
conjunction with the heater apparatus 1.
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Alternatively or additionally, the inlet for the ducting 12
may be in the base of the heater below the primary combustion
chamber 2 such as the inlet 15.
The air circulating means 6 may be provided in a number of
forms and also in a number of positions. In the preferred
apparatus as shown in figure 1, the air circulating means 6 may be
provided anywhere on communication with the ducting 12 to direct
the airstream as suggested. This includes the positioning in a
region beneath the primary combustion chamber 2 such as between
the inlets 15 and 14.
It should also be noted that the inlet 14 for connection to
an external source of air may be provided as an adjustable inlet
so that the proportion of air drawn from an external source and
the proportion of air drawn through an inlet such as inlet 15 from
within the room can be balanced. This adjustment may be through
the form of a baffle plate or similar which can adjust the size of
the opening 14. This adjustment may be provided during
manufacture and set to a suitable level or allow some manual or
controlled adjustment.
In addition or alternatively to the baffle plate or similar
control over the vent, the air circulating means 6 may be provided
in the form of a variable speed fan to increase draft through the
ducting 12 to increase the drawing of air from the outside. Of
course, in a preferred form, it may be desirable to provide
separate air circulating means 6 with at least one of these air
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circulating means being primarily to draw air through the inlet 14
from an external source. This additional air circulating means or
other form of control over the inlet 14 may be linked to a heater
control system (not shown) to allow variation in the inlet air.
In some territories, regulatory requirements set down levels
for ventilation in a room in which such a heater is housed, The
air drawn through the inlet 14 from an external source may be
measured through the inclusion of a suitable air flow sensor to
ensure that the adequate ventilation levels are being met. This
provides'a verifiable control over the air coming into the room in
which the heater is housed which will force air from within that
room out through any available exit. Should the inlet air fall
below a minimum limit, the heater can attempt to compensate by
increasing the fan speed, size of the inlet vent or, if necessary,
turn the unit off rather than continue to operate below a minimum
level. This may involve a link into the gas supply to shut off
the unit if the ventilation requirements are not being met.
The control over this inlet air from an external source can
also provide other benefits. In a controlled heater which may
involve a thermostatic control or similar, the quantity of gas
being supplied to the unit may be adjusted to control the heat
output from the heater. For example, a heating appliance may have
a maximum capacity of 25MJ. Once the thermostatic or other
controller suggests that the heater should reduce its output, this
may be controlled through control of the quantity of gas supplied
into the unit. However, as this gas supply continues to reduce,
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the flame height on the unit may also be effected. Once the gas
consumption falls below, for example, half its maximum level, it
may be decided that the flame height is now insufficient to
provide a visually aesthetic appearance. In circumstances where
gas consumption is of prime importance, such a reduction in flame
height may be of no great concern. However, if the visual
appearance of the fire is considered more important, it may be
desirable to make the unit operate less efficiently so as to
increase the flame height.
One manner of achieving this can be by again increasing the
air flow from outside of the room in which the heater is housed.
This increase of inlet air will effectively dump heated air within
the room out through any available means. This dumping of heated
air within the room allows the unit to continue to operate with a
higher gas flow and greater heat output and hence higher visible
flame.
Of course, control of the unit may also alter air flow
through the unit and gas consumption ae other variables related to
the efficiency of the heater, heat output and flame height.
Flammable fluid fuelled heaters 1 such as shown in the
present invention are also often provided with an artificial Iog
assembly within the primary combustion chamber 2 so as to give the
appearance of a wood fire place. Any attempts to minimise the
size of the overall heater 1 lead to some compromise being made in
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the size of the fire and the artificial log assembly such as the
artificial log assembly 16 comprising artificial logs 17.
Ia an attempt to provide a larger visual appearance to the
fire, at least one portion of the primary combustion chamber 2 may
be provided with a reflective surface such as the back wall 18.
~n this preferred form of the invention, the primary combustion
chamber 2 is also provided with side walls 19 and 20 which are
also provided as reflective surfaces to give a reflected image of
the log assembly 16 and flames 21.
The problem with such reflective surfaces is often the
appearance of two separate or distinct fires being the artificial
log assembly 16 and flames 21 and the reflected image of both.
There is an apparent discontinuity between the two images. In the
present preferred embodiment, artificial logs 17 are provided to
abut the reflective surfaces to provide an apparent continuity of
the log into the reflective surface.
Referring'to the rear base log 22 of the assembly 16, it can
be seen that the upper edge 23 of this log is provided to abut the
reflective back wall 18. As such the base log 22 is provided as a
half round log in the artificial log assembly 16. Upon being
abutted to the reflective surface 18, the reflective surface 18
provides a continuity to this log to give the appearance of a full
round log when the real and reflected images of the base log 22
are varied. The base log 22 is provided having a longitudinal
axis substantially parallel to the rear wall 18.
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Similarly, additional logs 24 may be provided which abut the
rear wall 18 such that the longitudinal axis of the Logs 24 is
substantially transverse to the plane of the rear wall 18. In
this manner, the length of the log 24 appears to be extended in
the reflective image and again providing some continuity into the
reflected image.
In this preferred form where side walls 19 and 20 are also
provided with reflective surfaces, the logs abutting those
surfaces such as the front log 17 abut the side wall 20
substantially perpendicular to the plane of that reflective
surface to provide some continuity into the reflective surface.
In this preferred form, at least a portion of the flames 21
will be provided intermediate of the logs perpendicular to the
rear wall 18 such as logs 24 and the side walls 19 and 20 so as
not to provide a gap in the flames in the primary combustion
chamber and shown in the reflective surface of the side walls 19
and 20. '
Another feature of the artificial log assembly 16 in this
preferred form is that the logs such as log 1~ across the heater 1
may be provided with a discontinuity such as a burnt out portion
25. Such artificial log assemblies are often constructed from
ceramic fibre logs and these may have substantial variations in
shrinkage in production. Therefore, the provision of logs across
the heating apparatus 1 to accurately abut against both the side
walls 19 and 20 can be exceedingly difficult. The provision of
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the burnt out portion 25 allows the transverse log such as log 17
to be provided with an apparent naturally occurring reason for not
extending entirely across the fire and creating the potential for
gaps against the side walls 19 and 20 should a tight abutment
against both be unable to be achieved.
The provision of the reflected extension of the logs 17,24,
etc., may lead to the selection of logs having diameters larger
than chosen for a normal assembly. The diameters are chosen in
keeping with those that appear natural for a fire as provided by
both the real and reflective images combined and in keeping with
the greater apparent length of the logs.
Thus it can be seen that at least the preferred form of this
invention provides a heating apparatus 1 which may provide an open
front S and yet provide some inhibition to the spillage of gases
from the primary combustion chamber 2.
In addition, the heater 1 provides an artificial log assembly
having reflective surfaces around the perimeter of the primary
combustion chamber and the artificial log assembly having logs
abutting the reflective surfaces so as to provide the appearance
of continuity into the reflective surfaces.
Where in the foregoing description reference has been made to
specific components or integers of the invention having
equivalents then such equivalents are herein incorporated as if
individually set forth.
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Although this invention has been described by way of example
and with reference to possible embodiments thereof it is to be
understood that modifications or improvements may be made thereto
without departing from the scope of the invention.
