Note: Descriptions are shown in the official language in which they were submitted.
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Title: Space Heater
Description of Invention
This invention relates to space heaters, and particularly but not
exclusively to apparatus for simulating flames in a solid fuel effect fire, to
give
the impression of flames emanating from combusting fuel.
A conventional space heater, herein referred to as being of the kind
specified, comprises a housing, heating means in the housing, a flame effect
means in the housing, a source of light to illuminate the flame effect means
in
the housing, and a screen through which light is transmitted from the housing.
Frequently a means is provided, such as by a fan or mechanical means, to cause
the flame effect means to move in the housing, and frequently the screen is
translucent, to make the visual effect produced within the housing somewhat
diffuse.
Several arrangements have been used in the past to simulate flames in
apparatus of the kind specified. For example, in GB-A-968568, there is shown
an apparatus in which the flame effect means comprises a plurality of
reflective
ribbons suspended adjacent to a rear part of the fire, the light source being
located forwardly of the ribbons, with a translucent screen also being located
forwardly of the ribbons, such that light from the light source reflected from
the
ribbons is incident on a rear face of the screen, giving a flame effect when
the
screen is viewed from the front.
As another example, it is known from GB-A-1186655 to suspend the
ribbons in front of the light source, so that light is transmitted between the
strips directly onto the translucent screen.
In the specification of our European patent specification EP 0986722 -
A, the flame effect means is in the form of a sheet of translucent material,
such
as crepe-de-chine, which is provided with a plurality of vertically-extending
elongate slits, the material being located optically between the light source
and
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the screen. A fan within the housing causes the material to billow, and the
slits
periodically to open a short distance, allowing light to be transmitted
directly
onto the screen, thus simulating a flame.
It has been appreciated by the present inventor, that in the past the
primary attention has been directed towards producing relatively high levels
of
light falling on the screen, and that this has not been particularly conducive
to
producing a high quality simulated flame.
Conversely, and in accordance with this invention, there is provided a
space heater characterised by the feature that light is directed from the
light
source through the flame effect means onto a reflector, and reflected light
passes again through the flame effect means onto the screen.
Preferably the flame effect means comprises a sheet of flexible material,
and is preferably generally matt, producing only a low level of reflected
light.
For example, the flame effect means may be provided by a sheet of silky
material, such as crepe-de-chine, preferably being of a dark colour, such as
dark
red, or even black.
Preferably the flame effect means provides openings, means being
provided to cause the flame effect means to move in the housing thereby
causing the openings to move.
Preferably the openings which are provided in the sheet are elongate,
and the material is suspended loosely within the housing, being caused to
"billow" by the flow of air directed there across, or by mechanical means.
Such
billowing will cause the slits to open, and for these openings to be seen to
travel
vertically in the upwards direction, or if desired, downwardly.
Light passing through the screen will be provided at four levels, as
follows:
a) light which passes from the source through the material of the
flame effect means to the reflector and from the reflector back through the
material of the flame effect means onto the screen;
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bi) light which passes from the source through an opening in the
material of the flame effect means to the reflector and through the material
onto
the screen;
bii) light which passes through the material onto the reflector and
onto the screen via the material of the flame effect means;
c) light reflected from the flame effect means directly onto the
screen;
d) light passing from the source through one of the openings onto
the reflector, and from the reflector back through one or other of the
openings
onto the screen.
Conveniently, levels a) and b) may be maintained at a low, ineffective
level, whilst the level c) is sufficient only to provide a low level
background
glow.
Light at level d) will be intermittent, but at a relatively high level,
providing a "smoky" flame effect which may achieve a high level of realism.
By varying the thickness and colour of the material which provides the
flame effect means, and by varying the thickness of the slits, the colour and
power of the lamp, and the degree of fogging on the screen, a high quality
flame effect means may be produced over a wide range of visual outputs.
Alternative to the use of the flame effect means being provided by a
sheet of flexible material, the flame effect means may comprise a plurality of
ribbons.
There will now be given a detailed description, to be read with reference
to the accompanying drawings, of a space heater which is a preferred
embodiment of this invention, having been selected for the purposes of
illustrating the invention by way of example.
In the accompanying drawings:
FIGURE 1 is a vertical sectional view of an electric fire which is the
preferred embodiment of this invention;
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FIGURE 2 is a schematic perspective view, illustrating principles of
performance of the fire; and
FIGURE 3 is an enlarged view illustrating the production of "openings"
in the flame effect means.
The space heater which is the preferred embodiment of this invention is
an electric fire, comprising a housing 4 having a base 6 and a rear wall 8.
Located forwardly of the front wall 10 an illuminated coal effect 12 may be
provided, in conventional manner. Heating means (not shown) is also
provided, in conventional manner.
Suspended within the housing 4 from an upper support 13 is a sheet 14
of a lightweight flexible material, such as crepe-de-chine, said sheet being
secured loosely by lower securing means 16, adjacent a lower end of the
housing.
Mounted adjacent to the lower securing means 16 is a fan 18 arranged to
direct a flow of air upwardly against the material 14, to cause the material
to
billow in an upward direction, and if desired, the lower end of the sheet may
be
secured to a rear wall of the fan housing.
As is seen from Figure 2, provided in the sheet 14 are a plurality of slits
20, said slits extending a majority of the height of the sheet 14, and being
generally parallel to the side edges of the sheet, there being in the
preferred
embodiment perhaps sixteen such slits disposed uniformly width-wise of the
housing 4.
Extending upwardly to an upper closure member 21 is a translucent
screen 24, conveniently of perspex or glass.
Provided within the housing 10 adjacent a front face of the sheet 14 is a
light source 28, arranged to direct light against the front face of the sheet
14,
conveniently the light source simultaneously providing an illumination for a
solid fuel (wood or coal) effect element 12.
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Under the influence of the current of air directly upwardly across the
sheet 14, the slits form openings 21 (see Figure 3), which move generally in
the
upwards direction as the sheet billows under the influence of the flow of air.
However, alternatively the air flow may be directed downwardly, to cause the
openings 21 to move in the downward direction. Light directed against the
sheet 14 in part passes through the material itself, falling against a
generally
triangular reflector 32 mounted on the rear wall 8 of the housing, light
reflected
therefrom passing forwardly through the sheet 14 and through the screen 24.
Some of the light transmitted against the sheet 14 will also pass through
the openings themselves in one direction of traverse of the sheet 14, whilst
some light will pass through openings formed by the slits 20 in both
directions
of traverse of the light. This latter light appears through the screen 24, and
hence to a viewer of the space heater as areas 30 of light moving upwardly of
the screen, quickly dissipating due to the lower degree of incidence of light
from the source 28 on the upper parts of the reflector 32, and by virtue of
the
shape of the reflector itself, simulating flickering flames.
The level of the background glow which will be observed on the screen
24 will primarily be produced by light being reflected from the front face of
the
material 14 through the screen. The intensity of the background glow will be
determined in part of course by the colour of the material of the sheet 14,
and
may, if desired, be enhanced by a reduction in thickness, so that there is a
small
contribution to the background glow, by light being reflected from the
reflector
32, and passing through the material 14 itself.
It has been found that, where the material 14 is afforded by crepe-de-
chine which is black in colour, and the light source 14 is arranged to
transmit a
white light, a "smoky" flame effect is produced. Alternatively, a warmer
effect
may be produced, by the use of crepe-de-chine of a dark red colour, together
with an orange light as the light source 14.
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Alternative to the use of the sheet 14 of crepe-de-chine, the flame effect
means may be provided by a plurality of ribbons, suspended between the
reflector and the light source in a manner such that light passes from the
source
28 to the ribbons, some light being reflected directly from the ribbons
through
the screen, other light passing the ribbons and being reflected by the
reflector
32, whereby light falling on the screen is at a number of different levels.
The
ribbons may be of translucent material, such as crepe-de-chine, but may be
partly reflective.
In the present specification "comprises" means "includes or consists of
and "comprising" means "including or consisting of'.
The features disclosed in the foregoing description, or the following
claims, or the accompanying drawings, expressed in their specific forms or in
terms of a means for performing the disclosed function, or a method or process
for attaining the disclosed result, as appropriate, may, separately, or in any
combination of such features, be utilised for realising the invention in
diverse
forms thereof.
