Note: Descriptions are shown in the official language in which they were submitted.
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DESCRIPTION
IMPROVEMENTS RELATING TO GAS BURNERS
.
The present invention relates to a gas burner
arrangement for use in a solid fuel efféct gas fire.
In certain known solid fuel effect gas fires, one
or more aerated gas burners provide the main heat and
glow and these or a number of under aerated or neat gas
burners provide the wispy flames which add visual
realism to the fire but little heat. This type of known
arrangement requires selective control of the various
burners to achieve optimum performance in respect of
heat output and visual effect, otherwise poor combustion
and sooting could occur. However such known fires are
inherently prone to sooting and Door combustion due to
the impingement of the flames on the si~ulated solid
fuel elements beneath which the burners are
conventionally located. Generally these known fires are
used with a heat exchanger and the products of
combustion have to be vented out via a chimney. If
purely a decorative fire the products of combustion are
immediately vented out via a chimney.
The aim of the present invention is to provide a
simple but high efficiency gas burner arrangement which
can provide a visual effect with good combustion,
allowing use in unvented and vented type appliances.
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According to the present invention there is
provided a gas burner arrangement for use in a solid
fuel effect gas fire, the burner arrangement comprising
a gas burner located in a combustion chamber directly
under a simulated solid fuel element bed, the gas burner
being arranged to burn gas which has been aerated with a
primary quantity of air, the combustion chamber having
inlets through which a secondary quantity of air can be
drawn into the combustion chamber to aid combustion
within the combustion chamber, the simulated solid fuel
element bed being provided with a number of apertures
through which flames and gas/air mix can pass to mix
with the ambient air and enable complete combustion to
occur outside the combustion chamber above the simulated
solid fuel element bed.
Preferably the burner used is a standard primary
aerated strip type gas burner adjusted to give yellow
tipped flames i.e. the quantity of primary air is
insufficient for complete combustion to occur. The
combustion chamber is preferably a rectangular open
topped box configuration with the burner set in the base
of the box, a simulated solid fuel effect construction
ma~e, for example, from a ceramic material, with said
apertures being located between the fuel elements,
closing the top of the combustion chamber. Inlets for
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secondary air are preferably located in the base region
of the combustion chamber below the level of the outlet
ports of the burner, and are designed to provide
insufficient air for complete combustion to occur, but
sufficient air to cause the gases to burn in the
combustion chamber with flames which are hot enough to
heat the simulated solid fuel effect construction to a
temperature at which sooting, i.e. depositing of carbon,
by the flames impinging on the simulated solid fuel
effect construction, is minimised. Excessive secondary
air would result in yellow sooting flames below the
simulated solid fuel effect construction. The balanced
quantity of primary and secondary air is preferably
sufficient to produce flames which are hot enough to
make the solid fuel effect construction glow. Pref~rably
the apertures in the solid fuel effect construction are
of a size which results in the combustion chamber
filling with burning gases, reverse air flow at the
edges of the apertures being minimised. Thus as the
combusting gases pass through the apertures in the
simulated solid fuel effect construction, they mix with
the ambient air and the combustion is completed with a
yellow flame. As the final combustion takes place in
free air and the flames do not imPinge on any
obstructions, the combustion performance attains
enhanced results. A chimney therefore may or may not be
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provided or even required. Further, a heat exchanger
may be provided if desired.
To facilitate ignition a pilot or ignition system
may be provided in or adjacent to the combustion
chamber. Further whilst a simplex burner allows the gas
feed rate to be turned down to very low levels, a duplex
type burner or two or more burners may of course be
alternatively provided.
The burner arrangement of the present invention can
thus be used to provide a visual effect without the
paramount need for a chimney and thus the present
invention may be used to advantage in, for example, a
portable cabinet heater fed with bottled gas.
The present invention will now be further
described, by way of example, with reference to the
accompanying drawings, in which:-
Fig.1 is a partially schematic cross-sectiona~ view
of a preferred embodiment of the present invention; and
Fig.2 is a partially cutaway perspective view of the
preferred embodiment of Fig.1.
The preferred embodiment of the present invention
illustrated in the accompanying drawings comprises a
burner arrangement 1 having a strip-like burner 3 which
is arranged to burn gas aerated with a primary quantity
of air, in a rectangular box-like combustion chamber 5.
The strip-like burner 3 is an elongate ribbon-type
burner with an arrangement of outlet ports 3a in a
generally horizontal upper surface 3b of the burner. The
combustion chamber 5 is made of metal and has an open
top which is closed over by a simulated solid fuel
effect construction 7 which is made of a ceramic
material and which has a number of apertures 13 between
the simulated fuel elements 15. Alternatively, the
combustion chamber can be completely made of a ceramic
material.
The burner 3 is provided in the base 9 of the
combustion chamber 5, directly beneath the simulated
solid fuel effect construction 7. Alternatively a
number of burners can be substituted. Also located in
the base region 9 of the combustian chamber 5 below the
level of the outlet ports 3a, are a number of elongate
inlet apertures 11 for allowing a quantity of secondary
dir to be drawn into the combustion chamber 5.
The burner 3 is designed so that the gas it burns
is insufficiently aerated by the primary air to produce
complete combustion i.e. the quantity of primary air is
only sufficient to produce yellow tipped flames when the
fuel effect 7 is not in position. A quantity of
secondary air is thus drawn into the combustion chamber
5 via the inlet apertures 11, though this is
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insufficient to complete combustion but sufficient to
cause the gases to burn in the combustion chamber S with
flames which are hot enough to heat the simulated solid
fuel effect construction 7 to a temperature at which
sooting by the flames impinging on the simulated solid
fuel effect construction 7, is minimised. The
combusting gases pass through the apertures 13 in the
simulated fuel effect construction 7 the apertures 13
being of a size such that the combustion chamber 5 is
filled with burning gases and reverse air flow around
the edges of the apertures 13 is minimised. As the
combusting gases pass through the apertures 13 they mix
with the ambient air, combustion being thus comDleted
with a yellow flame. As the final combustion takes
place in the free air and the flames do not impinge on
any obstructions, the combustion figures are good. A
chimney or flue need not therefore be necessary. -
The simulated~solid fuel effect construction 7 isthus heated by the flames in the combustion chamber and
thus acts as a radiant heater, with the hot gases
passing through the apertures 13 causing the edges of
the aperture 13 to become heated sufficiently to glow
red as per a real fire, the yellow flames produced by
complete combustion in the ambient atmosphere adding to
the visual realism of the fire as well as to the heat
output.
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The fuel effect 7 can be constructed of multiple
levels and segments from ceramic type materials or a
combination of metal and ceramic or all metal
configurations. These can be designed so as to modify
the combustion characteristics to thus induce variations
in the flame colour and pattern, in conjunction with
variations to the combustion chamber 5 which may be
constructed of materials other than metal.
To facilitate ignition an igniter 17 in the form of
a pilot or ignition system can be located in the
combustion chamber 5.
The present invention thus provides a burner
arrangement which provides a visual effect without the
need for the previously essential chimney or flue.
