Note: Descriptions are shown in the official language in which they were submitted.
CA 02262867 1999-02-23
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FIREPLACE WITH ELECTRIC ELEMENT
This invention relates generally to fireplaces that have an electric element.
In
particular it relates to fireplaces having a simulated log display and an
electric heating
element for causing a portion of the display to appear to glow.
Background Art
Gas fireplaces generally include a casing for containing the fire, a firebox
mounted within the casing in a manner which permits air from inside a dwelling
to
circulate thereabout and be warmed, a gas burner for connection to a gas
supply, and
an arrangement of simulated solid fuel material located relative to the burner
in a
manner intended to give an aesthetically pleasing appearance. In a typical,
front
opening fireplace, the casing and firebox are provided with an opening and a
window
respectively, by which means persons may view the fire. "Mufti-open"
fireplaces
having two, three, four, or more viewing windows are also known. For example,
a
see-through fireplace has at least two parallel windows on opposite sides of
the firebox.
A peninsula fireplace has windows on three sides of a four sided firebox. In
some
instances the simulated solid fuel is arranged to have the appearance of a
coal fire, or
bed of coals. In North America simulated wood log fires predominate. Gas
fireplaces
are also available as fireboxes, or merely as burner displays, for insertion
into an
existing fireplace enclosure.
The nature of simulated fire displays is such that it may be advantageous to
locate the simulated logs in a generally rearwardly ascending display such
that more
of the fire is visible. Most commonly the simulated logs are arranged in a
tier-like
fashion. However the logs or coals may be arranged, it is generally desirable
to
produce a corresponding flame display that interacts with the logs in a manner
which
gives the appearance of the log set burning. The careful matching of burners
to
simulated log or simulated coal arrangements to produce aesthetically pleasing
results
is a science of much subtlety.
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In terms of interaction between the flames and the simulated logs, it is known
to direct gas jets against simulated log or ember materials to simulate the
appearance
of glowing coals, and that cooler flames have a more yellow appearance similar
to the
appearance of a natural wood fire. However, it is also known that directing
flames to
impinge upon relatively cool, high thermal mass ceramic or concrete logs may
lead to
incomplete combustion, sooting, and unacceptable pollutant emissions. One
technique
used to produce simulated glowing embers is to place a gas manifold in or
beneath a
bed of emberizing material, such as low density rock wool. Another technique
is to
direct flames at soft ceramic material, whose surface then glows. In either
case, a
stable flame pattern may yield a constantly glowing body rather than a
flickering effect.
The production of a glowing portion of a log, or an ember strip, or a bed of
simulated glowing coals, often involves the careful placement of ember
simulating
materials relative to flames emanating from a burner. In some instances the
glowing
material is loosely deposited on the burner itself, or in a tray about the
burner. The
glow produced may also vary on the installation of a log set on delivery, a
relatively
small change in the spacing between logs, or their relative angles of
placement, may
result in an unexpected hot or cool spot. It is advantageous to control the
relative
dimensions of adjacent glowing and non-glowing elements to reduce the
likelihood of
such unexpected results.
The appearance of the fire can be enhanced by having either glowing embers
on the firebox floor, or by having portions of the log glow without the
appearance of
flames, to simulate glowing coals or embers. In some instances it may be
difficult to
obtain the desired effect with a gas burner. The embers may be on the firebox
floor,
such that it may be difficult either to locate a burner below them or to
provide a desired
airflow to achieve relatively clean combustion. Alternatively, the embers may
be near
the window in a position where only poor airflow is available. Further still,
the desired
glowing may be in a location where a flame heat source would be too visible in
terms
of the desired aesthetic effect. At other times, users may desire a modest,
glowing
appearance, yet may not wish to turn on the gas burner, either because they
desire a
low glow, or because they wish a glowing display without the full heat output
of a gas
burner. In all of these instances it would be desirable to have a heat source
that can
be heated to produce a glowing effect, without the need to use a gas burner.
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Alternatively, it may be desirable to have a heat source that glows, with the
glow being
visible in some way, whether reflected or partially transmitted through an
adjacent
ember simulating medium such that the ember simulating medium appears to glow
like
a bed of glowing embers.
Additionally, inasmuch as a wood fire tends to change its appearance over
time,
it would be advantageous to be able to cause different portions of the display
to glow
at different times.
Summay of the Invention
In one aspect of the invention there is a simulated fire display apparatus
that
comprises an electric heating element for connection in an electric circuit.
There is
simulated fire display material for placement in a position adjacent to the
electric
1 S heating element. The electric heating element is heatable to give the
simulated fire
display material a glowing appearance when in that position adjacent to the
electric
heating element.
In another aspect of the invention there is a simulated fire display
apparatus.
The simulated fire display apparatus has an electric heating element for
connection in
an electric circuit. The display also has simulated fire display material for
placement
in a position to be heated by the electric heating element. The simulated fire
display
material is heatable to incandescence by the electric heating element when in
that
position.
In an additional feature of that aspect of the invention, there is another
electric
heating element for connection in an electric circuit, and simulated fire
display material
for placement in a position to be heated by the other electric heating
element. The
heating elements are separately controllable.
In another additional feature of that aspect of the invention, there is an
electrical
control for installation in the same electrical circuit as the electrical
heating element,
the control being operable in at least two positions. The electrical heating
element is
operable in two states, each state corresponding to one position of the
control.
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In still another further additional feature of that aspect of the invention,
there is
an electric control mountable in the same circuit as the electrical heating
element. The
control is operable in low, medium and high settings. The electric heating
element is
operable in low, medium and high heating states corresponding to the low
medium and
high settings of the control.
In yet another additional feature of that aspect of the invention, there is an
electric
control mountable in the same circuit as the electrical heating element, the
control being
continuously variable to permit continuously variable adjustment of the
operation of the
electrical heating element.
In still another additional feature of that aspect of the invention, there is
a control
mountable in the same circuit as the electrical heating element, the control
having a fixed
schedule for varying the operation of the electrical heating element as a
function of time.
In another additional feature of that aspect of the invention, there is a
controller
mountable in the same circuit as the electrical heating element. The
controller has a
schedule for varying the operation of the electrical heating element as a
function of time.
The controller has at least one input interface, and is responsive to at least
one input at the
interface to vary the schedule.
In an alternative additional feature of that aspect of the invention, there is
a
controller mountable in the same circuit as the electrical heating element.
The controller
has a random input function to vary the operation of the electric heating
element
unpredictably as a function of time.
In yet another feature of that aspect of the invention. The controller has a
programmable microprocessor for varying the operation of the electric heating
element
as a function of time. In still yet another feature of that aspect of the
invention, the
programmable microprocessor has a user programmable interface. In still yet
another
additional feature of that aspect of the invention, the programmable
microprocessor has
a random number generator to permit operation of the electric heating element
to vary
unpredictably over time.
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In a further feature of that aspect of the invention, the display has more
than one
electric heating element, simulated ember materials locatable for heating by
respective
ones of the elements to a glowing condition, and a microprocessor connected to
control
operation of the heating elements to cause the glow emitted from the display
apparatus
$ to vary over time.
In yet a further feature of that aspect of the invention, there is at least
one
simulated solid fuel element and a gas burner placed to produce flames
adjacent to at least
one of the at least one simulated solid fuel elements. In still a further
feature of that aspect
of the invention, the electric heating element and the gas burner are
separately
controllable.
In still yet a further feature of that aspect of the invention, the apparatus
is
locatable in a firebox having a floor and a viewing opening through which the
simulated
1$ fire display apparatus can be seen. The simulated fire display material is
simulated ember
material for placement upon the floor to at least partially conceal the
electric heating
element, and the electric heating element is electrically insulated from the
floor.
In another feature of that aspect of the invention the apparatus is locatable
in a
firebox having a floor and a viewing window. The electric heating element is
located
closer to the window than the solid fuel element. In yet another additional
feature of that
aspect of the invention, the electric heater element is electrically insulated
from the
firebox floor, and the simulated ember material is heaped on the firebox floor
generally
forward of, and below, the simulated solid fuel element.
2$
In still another additional feature of that aspect of the invention, the
apparatus
includes a set of the solid fuel elements arranged to simulated a wood fire
supported
above the level of the firebox floor. The electric heater element is
electrically insulated
from the firebox floor, and the simulated fire display material is simulated
ember
material arrayed on the firebox floor to conceal the electric heater element.
In yet another additional feature of that aspect of the invention, the
electric heating
element has a mounting for accommodating thermal expansion thereof. In another
additional feature of that aspect of the invention, the mounting is a sliding
mount. In yet
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a further additional feature of that aspect of the invention, the electric
heating element
is bent.
In another aspect of the invention, there is a simulated flrelog for a
simulated fire
display. The firelog has a body formed to simulate, on a least one face
thereof, the
appearance of a piece of firewood. The body has an accommodation for an
electric
heating element. The firelog has an electric heating element located in the
accommodation and has terminals for connection in an electric circuit. The
simulated
fire display material is located in a position adjacent to the electric
heating element.
The simulated fire display material and the face are visible together. The
electric
heating element is operable to give the fire display material a glowing
appearance.
In an additional feature of that aspect of the invention, the body includes a
soft
ceramic portion heatable by the electric element to a glowing state. In
another
additional feature of that aspect of the invention, the body has a shield for
at least partially
concealing the electric element from view. In yet another additional feature
of that aspect
of the invention, there is another accommodation, another electric heater
element
mounted therein, and simulated fire display material to be given a glowing
appearance
by the other element.
In another aspect of the invention, there is a fireplace display. The
fireplace
display has a set of simulated firelogs, simulated ember materials arrayed
adjacent to the
firelogs and an electric heater element mounted to give at least one of (a) at
least a portion
of one of the firelogs, and (b) at least some of the simulated ember
materials, a glowing
appearance.
In an additional feature of that aspect of the invention, the electric element
is
concealed from view by at least one of (a) at least a portion of one of the
firelogs, and (b)
at least some of the simulated ember materials.
In another additional feature of that aspect of the invention, one of the
simulated
firelogs has a body formed to simulate, on a least one exposed portion
thereof, the
appearance of a piece of firewood. The body has an accommodation for an
electric
heating element. The electric heating element is located in the accommodation
and has
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terminals for connection in an electric circuit. The simulated fire display
material is
located in a position to be given a glowing appearance by the electric heating
element.
The simulated fire display material and the exposed portion are visible
together.
In another further additional feature of that aspect of the invention, there
is a
burner for producing a flame pattern adjacent to at least one of the simulated
firelogs. In
yet another additional feature a simulated firelog has a portion placed to be
heated to a
glowing state by the burner.
In another additional feature of that aspect of the invention, the electric
heater
element is mounted to heat the simulated ember materials to a glowing state,
and the
simulated ember materials are located to conceal the electric heater element.
In yet
another feature of that aspect of the invention, the simulated ember materials
are placed
to lie in the foreground of the simulated firelog having the portion placed to
be heated
to a glowing state by the burner.
In another aspect of the invention, there is a method of simulating the
appearance
of a fire. The method includes arranging a simulated fireplace display in a
position to
be viewed, the display including at least one portion to be given a glowing
appearance,
providing an electric heating element adjacent to the at least one portion,
and operating
the electric heating element to heat at least one of the portions to a glowing
condition.
In an additional feature of that aspect of the invention, in which the display
has
a burner for producing a flame array, and solid fuel simulating elements for
interaction
with the flame array, the method includes the step of operating the burner to
produce
the flame array while operating the electric heating element.
In another additional feature of that aspect of the invention, there is the
step of
operating the electric heating element to heat at least one of the portions to
a glowing
condition and the step of operating the burner to heat another portion of the
simulated
fireplace display to a glowing condition.
In yet another additional feature of that aspect of the invention in which the
simulated fireplace display includes ember simulating elements, the step of
arranging
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includes placing a quantity of the ember simulating elements in the foreground
of the
display, and placing the electric heating element amongst the ember simulating
elements.
In still yet another additional feature of that aspect of the invention in
which the
display includes ember simulating elements and simulated firelogs, the step of
arranging
includes placing at least one of the simulated firelogs in the background of
the display
relative to the ember simulating materials, and the step of operating the
burner includes
producing flames in front of at least a portion of the one at least one,
background, firelog,
whereby the ember simulating materials and flames of the burner are both
visible.
In still another additional feature of that aspect of the invention in which
the
display includes ember simulating elements, the step of arranging includes
placing the
ember simulating elements in a position to appear to at least partially
underlie the solid
fuel elements.
In yet a further additional feature of that aspect of the invention in which
the
display includes ember simulating elements and simulated fireplace gratework,
the step
of arranging includes placing the solid fuel elements in a position to appear
to be
resting on the gratework, and placing the ember simulating materials in a
position to
appear to at least partially underlie the gratework.
In still yet another additional feature of that aspect of the invention, the
step of
operating the electric heating element includes varying the operation of the
electric
heating element over time. In another additional feature of that aspect of the
invention,
the step of operating includes varying the operation over time according to a
fixed
schedule. In an alternative additional feature of that aspect of the
invention, the step of
operating includes varying the operation over time according to a schedule
input by a user.
In another alternative additional feature of that aspect of the invention, the
step of
operating includes varying the operation over time according to an automated
schedule
having a random input function. In a further additional feature of that aspect
of the
invention, the step of operating the burner includes varying the flame array
over time,
and the step of operating the electric heating element includes varying the
operation of
the electric heating element over time.
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In another additional feature of that aspect of the invention, the step of
providing
includes providing more than one electric heating element. The step of
arranging
includes arranging at least one of the portions in a position adjacent to each
of the
electric heating elements and the step of operating includes operating the
electric
heating elements to give the at least one portion a glowing appearance.
In yet another additional feature of that aspect of the invention, in which at
least
one of the portions to be given a glowing appearance includes ember simulating
materials, the display includes at least one simulated firelog, and at least
one of the
portions to be given a glowing appearance is a portion of the simulated
firelog, the step
of operating includes heating one electric element to give the ember
simulating
materials a glowing appearance, and heating another electric element to give
the
portion of the simulated firelog a glowing appearance.
In still yet another additional feature of that aspect of the invention, the
step of
providing includes providing a plurality of electric heating elements. The
steps of
operating the burner and of operating the electric heating elements include
varying the
operation of the burner and the electric elements over time to produce a time
varying
appearance of the fire.
Brief Descril?tion of the Drawings
Figure 1 shows an example of a general arrangement, exploded view of a
peninsula fireplace assembly suitable for incorporating an embodiment of the
present
invention.
Figure 2 shows an isometric view of a firebox floor panel of the fireplace
assembly of Figure 1 with pan burners and electric heating elements as mounted
thereon.
Figure 3 shows the floor panel of Figure 2 with burners removed and a pair of
electric heating elements in exploded view.
Figure 4 shows a detail of the floor panel of Figure 3, as assembled.
Figure 5 shows an isometric view of a burner tray mountable in the floor panel
of Figure 2.
Figure 6a shows an isometric view of the heating element of Figure 2.
CA 02262867 1999-02-23
Figure 6b shows a top view of the heating element of Figure 2.
Figure 6c shows a side view of the heating element of Figure 2.
Figure 6d shows an end view of the heating element of Figure 2.
Figure 6e shows an isometric view of an alternative heating element to that of
5 Figure 2 having end portions bent through a 90 degree corner.
Figure 6f shows an isometric view of an alternative heating element to that of
Figure 2 having a U-shape.
Figure 7 shows a partial wiring diagram for the fireplace of Figure 1.
Figure 8 shows a front view of a log set mounted on an alternative pan burner
10 to the pan burners of Figure 2, with an electric heating element, shown in
partial scrap
view, embedded in simulated ember material.
Figure 9 shows a cross section of the alternative example of a fireplace of
Figure 8.
Figure l0a shows an example of a fireplace having a single viewing window,
in partially exploded view.
Figure lOb shows the fireplace of Figure l0a with window and front trim
panels removed and an electric heating element in exploded view.
Figure 11 shows an example of a corner-installation fireplace similar to the
fireplace of Figure 1.
Figure 12a shows a front view of an example of a simulated solid fuel element
having electric heating elements embedded therein.
Figure 12b shows a cross section of the simulated fuel element of Figure 12a.
Figure 13 shows a schematic for automatic control of the fireplace of Figure
8.
Figure 14a shows a front view of an example of a simulated solid fuel element
having electric heating elements cast therein.
Figure 14b shows a cross section of the simulated fuel element of Figure 14a.
Figure 15 shows a front view of an example of a simulated solid fuel element
having electric heating elements mounted to the face thereof.
Best Mode for Carrying Out the Invention
The description which follows, and the embodiments described therein, are
provided by way of illustration of an example, or examples of particular
embodiments
of the principles of the present invention. These examples are provided for
the purposes
CA 02262867 1999-02-23
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of explanation, and not of limitation, of those principles and of the
invention. In the
description which follows, like parts are marked throughout the specification
and the
drawings with the same respective reference numerals. The drawings are not
necessarily
to scale and in some instances proportions may have been exaggerated in order
more
clearly to depict certain features of the invention.
Referring to Figure 1, a gas fireplace assembly is shown generally as 20. It
has a
firebox, 22, having a pair of end walls 24 and 26, a pair of front and rear
walls 28 and 30,
a floor 32, and an upper panel 34. The front, rear, and near end walls 24, 28
and 30 of
firebox 22 are closed in by viewing panels, in the nature of windows 36 and 38
and 40
respectively. The far end wall, 26 is closed in by a panel in the nature of a
metal sheet 42
having a stamped simulated brickwork pattern. Metal sheet 42 forms the inner
wall of an
air plenum 44. An end sheet in the form of a vertical channel section 46
encloses the end
of fireplace 20, generally, and provides the balance of the periphery of air
plenum 44.
Firebox 22 is mounted within a four cornered casing 52, having corner elements
in the nature of the formed left and right corners of channel section 46,
noted above, and
front left and right hand near end corner pillars 54 and 56. Casing 52 has a
bottom panel
58 and a top panel 60. Vertical stand-offs in the nature of mounting feet 62
and 64 stand
upright from bottom panel 58, and support firebox floor 32 within the
rectangular space
defined by the corners of channel section 46 and pillars 54 and 56. The space
between
firebox floor 32 and bottom panel 58 defining a sub-floor plenum 70 that is
closed in on
front, rear and near end sides by vented trim panels 72, 74 and 76
respectively.
Similarly, upper panel 34 of firebox 22 is mounted within channel section 46
and
pillars 54 and 56 with spacing from top panel 60 of casing 52 to define an
upper plenum
78. The front, rear and near faces of plenum 78 are contained within louvered,
or vented
trim panels 80, 82, and 84 respectively.
A coaxial direct vent mounting 86 is shown mounted to top panel 60 of casing
52.
Mounting 86 mates with conventional co-axial ducting (not shown), whether
rigid or
flexible, that has external ambient intake and exhaust. Cool intake air enters
the annular
space between the outer ductwall and the inner duct wall. It is carried into a
collector box
(not visible) inside plenum 44, and downward in a set of parallel intake pipes
(not visible)
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and under floor 32 where it flows in the space between floor 32 and a subfloor
220,
(described below) before reaching the inside of firebox 22. Exhaust from
firebox 22 flows
through a flue 88 mounted in upper panel 34. Flue 88 extends to form the inner
coaxial
duct portion of co-axial fitting 86.
Plenums 70, 44 and 78 are connected such that room air that enters through the
trim work of lower plenum 70 can flow upwardly in plenum 44, and can exit
through the
louvered or vented trimwork of upper plenum 78. A blower, or fan 90 as
indicated in
Figure 7, is mounted at the base of plenum 44 to enhance this flow, thereby
tending to
improve heat transfer to the room from fireplace assembly 20.
Firebox 22 contains a burner assembly 100, and a display assembly 102 that is
mounted to co-operate with burner assembly 100 to produce a simulated solid
fuel
fireplace appearance. In the preferred embodiment display assembly 102 is in
the nature
of an array of soft ceramic, molded, simulated wood fire logs, but could be
another type
of display, such as a simulated coal fire display. Burner assembly 100
includes front and
rear pan burners 104 and 106, and a gas control module 108 that is, in use,
connected by
gas piping to a source of gas fuel (not shown). In the preferred embodiment
the fireplace
is suited for burning natural gas, but in alternate embodiments it could use
propane or
some other suitable fuel.
In use gas is supplied to burners 104 and 106, which produce flame patterns
corresponding to the shape and arrangement of the simulated firelogs to be
situated upon
them. In the preferred embodiment of Figures 1 and 2, pan burners 104 and 106
are single
venturi, flat pan burners, each having a flame port array 110 and 112 whence
gas jets may
emanate in a pattern to yield an aesthetically pleasing display when
juxtaposed with the
adjacent simulated solid fuel elements in the nature of simulated firelogs.
Display
assembly 102 has a set of simulated solid fuel elements in the nature of soft
ceramic
moulded simulation logs 114, 116, 118, 120, 122 and 124. These logs are keyed
to
sit on burners 104 and 106 and to interact with the flame display.
Referring to Figures 2, 3 and 4, in the preferred embodiment floor panel 32 is
a sheet metal part having a stamped, simulated rectangular brickwork pattern.
A
rectangular opening 130 is defined generally centrally in floor panel 32, and
a
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peripheral fitting in the nature of a flanged rectangular frame 132 is mounted
thereabout. Frame 132 has a pair of long sides 134 and 136 running generally
parallel
to the planes defined by front and rear viewing windows 36 and 38, and a pair
of short
sides 138 and 140 running generally parallel to end walls 26 and 28
respectively. Each
of these long and short sides has a flange bent to lie against, and for
mounting to, floor
32 with screws (rivets, other fasteners, or a suitable bonding agent could be
used).
Long sides 134 and 136 have upturned portions, or legs, 142 and 144, which
stand
substantially perpendicular to floor 32. Short sides 138 and 140 have notched
upturned
legs 148 and 150, the notches 152 and 154 being formed to give a positive
locating
index in the nature of an accommodation, or a seat for front and rear flat pan
burners
104 and 106. Secondary intake air enters the firebox in the gap between
burners 104
and 106.
Gratework, in the nature of a decorative, simulated grating element 160, with
feet 162 and 164 is mounted to stand upon floor 32 before burner 104,
partially hiding
or disguising it. A similar simulated grating element is placed between burner
106 and
window 38. Although the relatively plain grating element, 130, is preferred,
other
simulated grating elements can be used, such as that shown in Figure 8 that
has
upturned tines 166 to simulate the ends of cross rungs such as support wooden
logs in
a fireplace. Other styles of grating or grillwork can be used. In simulated
fireplaces of
this nature the gratework, whether including gratings, grilles, andirons or
similar
items, need not actually support the firelog display. Rather, the gratework
tends to give
the appearance of supporting the logs in the manner of a real wood (or
possibly coal)
fire, whether it does or not.
Floor panel 32 need not be a stamped sheet metal part, but could be a moulded
part, such as can be made from metal, or ceramic, whether low density ceramic
or
high density ceramic. A ceramic part could include one or more ceramic
elements
intended to operate at pyrolytic temperatures. Upturned legs 148 and 150 of
short
sides 138 and 140 of frame 102 can be cut not only to support flat pan burners
84 and
86 of the preferred embodiment, but also, with suitable changes in fireplace
and display
dimensions, to support flat pan burners in a tiered arrangement, that is, at
different
heights in an ascending, or step wise manner, or to support stepped pan
burners, or to
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14
support a tube burner or burners of single or multiple burner runs. Further
still, the
sides of frame 132 can be cut and formed to support elements of a log display
directly.
Electric heating elements 170 and 172, in the nature of glowing ember rods,
are
shown in Figure 4. The mounting of these elements is typified in Figure 2, in
which
element 170 is shown standing upwardly of floor 32, extending generally
parallel to,
and forwardly of, burner 104 and decorative grating element 160. In this
position
simulated solid fuel ember materials in the nature of simulated ash, charcoal
or
clinkers, indicated generally as 174, can be placed, piled, heaped, or arrayed
on or
about heating elements 170 (or 172, as the case may be) both to conceal or
camouflage
element 170, and to be given a glowing appearance by it in use. Only a sample
of
ember materials 174 is shown in Figure 2 for the purpose of conceptual
illustration. In
use ember materials 174 tend to conceal all, or nearly all, of element 170.
Some small
parts of element 170 can remain visible though the small, interstitial gaps
between
1 S ember materials 174 In the preferred embodiment, simulated ember materials
174 are
soft ceramic lumps having the shape of pieces of gravel or relatively large
pebbles.
These lumps, or portions of them, are suitable for heating to incandescence
(that is, to
a glowing condition) when placed against electric heating elements 170 and
172. When
several such lumps are placed about electric heating element 170, or 172, the
element
heats those portions of the lumps contacting the element to a glowing
temperature.
Part of the glow from element 170 is diffusely reflected off the surfaces of
adjacent
lumps, and is filtered through the spaces between the lumps to yield the
appearance of
a glowing bed of embers. Ember materials 174 can be made of soft ceramic as
preferred, or alternatively, of glass wool, rock wool, or other suitable
material for
heating to a glowing temperature.
In an alternative embodiment, ember materials 174 can be loose vermiculite
heaped on or about elements 170 and 172. It has been noted that vermiculite
particles
tend not to glow to the same extent as the soft ceramic lumps, but rather tend
to lie
loosely such that the reddish glow of the electric heating rods (elements 170
and 172,
for example) is filtered up through the vermiculite to give the appearance of
a glowing
bed of coals or embers. That is, the simulated ember materials can be heated
to a
temperature at which they glow, or they can act as a filtering, transmitting,
or
reflecting medium for interacting with the thermal radiation in the visible
spectrum
CA 02262867 1999-02-23
1$
(that is, the glow) emanating from the heating elements themselves, without
necessarily
glowing themselves, or both. In either case, heating element 170 gives the
display the
appearance of glowing solid fuel elements, or glowing portions of a solid fuel
element
in the nature of a bed of embers, of charcoal, or the like.
In the preferred embodiment of Figure 3, heating elements 170 and 172 are of
identical design. Referring to the more detailed drawings of Figures 6a, 6b,
6c, and
6d, heating element 170 (or 172) has a relatively long, substantially straight
central
portion 180 having a length corresponding generally to the length of flat pan
burner
104 (or 106). At either end of straight portion 180 there is an arcuate, or
bulbous
portion 182 having an exaggerated arc that has a first, upwardly bending
portion 184,
of about 60 degrees of arc, and then a reverse bend, downwardly bending
portion 186,
of about 150 degrees of arc. Extending vertically downwardly from the distal
end of
bulbous portion 182 is a termination prong 188, having at its farthest end a
spade
terminal, 190. A sleeve 192 is formed about the midst of prong 188, and a
fitting, in
the nature of a mounting plate 194 is located to mount to sleeve 192. Mounting
plate
194 has a location pick-up hole 196.
Floor 32 has a pair of rectangular slots 200 provided to accommodate the
prongs 188 at one end of each heating element 170 and a pair of through
clearance
holes 201 to accommodate the prongs at their other respective ends. Adjacent
to slots
200 are a pair of holes 202 and 204. A slide fitting 206 is mounted to holes
202 and
204 to capture an edge of mounting plate 194. The bulbous ends of heating
element
170, and the accommodation of slots 200 permit some tolerance of thermal
expansion
along the length of heating element 170.
The bulbous shape is preferred because it facilitates placement of portion 180
closer to floor 32, without touching, than would otherwise be the case with a
single 90
degree bend commencing at floor level, as shown in the alternative embodiment
of
Figure 6e. This smaller clearance distance tends to permit a reduction in the
amount
of ember material required to screen or conceal element 170. An optional
insulated
stand-off leg 208 is shown at mid span of straight portion 180, and is
provided to
maintain a spacing between portion 180 and floor 32. Alternative shapes and
sizes of
stand-off can be used, including bi-pod stand-offs, angle brackets, and
insulated disc
CA 02262867 1999-02-23
16
spacers. A stand-off is not necessary where the length of the span is
relatively short,
such that adequate support is provided at ends. In Figure 6e, an alternate
heating
element 210 is shown having 90 degree rounded corners 212 in place of the
bulbous
corners described above.
In the preferred embodiment of Figure 1, the heating elements, the simulated
ember materials, and associated electrical connection and stand-off hardware
can be
provided as a kit for retro-fit installation in existing direct vent, B-vent
or fireplace
insert units. In the preferred embodiment heating element 170 is a nominally
19" (48
cm) long, 425 W heating element made by Glengarry Industries of Guelph,
Ontario,
Canada. In an alternative embodiment, a nominally 24" (60 cm) long 575 W
heating
element has been used, also manufactured by Glengarry Industries.
Although heating elements 170 and 172 are preferred, it is not necessary that
either heating element be formed in a straight line, or that they be the same
in size and
shape. They could, for example, have a generally U-shaped profile, like the
horseshoe
shaped element 214 shown in isometric view in Figure 6f, or an arbitrarily
shaped
meandering profile, such as, for example, for following the contours of one or
more
simulated logs, or for following a ridge of simulated ash and embers. The
profile need not
be planar, but could extend out-of plane (that is, in three dimensions),
subject to the
ability to mask, camouflage, or hide, the heating element from view with
either simulated
embers, simulated logs, grillwork, supports, or other structure within firebox
22. Thermal
expansion of the heating element is a consideration in choosing the shape and
size of the
element, and the means for masking it from view. An alternate style of stand-
off clip is
illustrated as 212 in Figure 6f.
Burner assembly 100 also has a burner tray, or subfloor 220 having a pair of
upwardly formed flanges 222 and 224 that are fastened to the supporting
structure of
fireplace 20. A web 228 extends between, and perpendicular to, flanges 222 and
224. Gas
control module 108 is mounted to the underside of a mounting plate 232 that
locates
generally centrally in the well-like area between flanges 222 and 224, and web
228. An
electronically operated pilot assembly controlled by gas control module 108 is
indicated
as 234. A pair of gas fittings 236 and 238 are located to deliver gas to the
inlet nozzles
(not shown) of flat pan burners 104 and 106 when those burners are in place.
Heating
CA 02262867 1999-02-23
17
element lead wires 240, 242, 244 and 246 with sockets for mating with spade
terminals
190 are fed through a grommetted aperture 250, and are arrayed to connect with
the
respective ends of heating elements 170 and 172. A wiring diagram is shown in
Figure
7, and shows the relationship of a manually operated switch 252 and other
fireplace
circuitry, such as a connector 254 for connection to a source of line power,
and for heat
exchange fan 90. In the preferred embodiment shown, a single switch is
operable to turn
on both heating elements 170, 172.
Although a single manually operated switch is preferred, in alternative
embodiments it is possible to use individual switches for each element. In
this way, if
people are seated only to one side of the fireplace, only one element need be
turned on.
Users may also prefer a lower heat output, or lower electrical consumption in
some
instances. Further still, although only two heating elements are used, to
present the
appearance of glowing embers along the long sides of display assembly 102,
additional
elements can be used, such as along the near end of display assembly 102 to
present, for
example, a bed of glowing coals extending generally parallel to window 40. It
is not
necessary that more than one electric element be used. For example, in some
circumstances, such as for fires having a single viewing window, a single
heating element
may be satisfactory. Further, subject to allowance for thermal expansion and
contraction
of the heating elements, a single heating element could be shaped to extend
for heating
embers on more than one side of the fire display.
In the preferred embodiment, the simulated ember materials include a loose
stainless steel wool skein, or strands, or tufts, that have been placed next
to heating
element 170 or 172. Preferably, the stainless steel wool is formed into a
thin, inverted U-
shape akin to a channel, to sit over heating element 170. Other simulated
ember materials,
namely soft ceramic lumps, or alternatively, vermiculite particles, are then
placed in
contact with, upon, or cradled by, the stainless steel wool. The loose
stainless steel wool
has a tendency to entangle the ember materials, and to discourage the soft
ceramic lumps,
or, alternatively, the vermiculite particles, from migrating away from heating
element 170
or 172. In this way the stainless steel wool acts as a fouling or entanglement
medium, or
as a retaining medium for discouraging the migration of the other ember
simulating
elements that might otherwise occur more rapidly as a result of repeated
thermal
expansion and contraction of heating element 170 or 172.
CA 02262867 1999-02-23
18
In an alternative embodiment, some or all of the simulated embers can be
retained
by bonding or mechanical means in a permanent position to form a ridge or berm
on either
side of the heating elements to discourage or prevent loose ember simulating
materials
heaped on top of the heating elements from migrating away from the heating
elements
S repeated use. Alternatively, the electric element can be located within a
permanent, loosely
packed berm of simulated ember material. In a fizrther alternative embodiment,
floor 32
can be provided with ember retaining brackets, or can be formed with ripples
or contours,
to discourage or prevent heaped embers from moving away from the heating
elements
after repeated thermal cycling.
The present invention is not only applicable to peninsula fireplaces, but also
to
single window fireplaces, such as gas fireplace 280 shown in Figures l0a and
lOb, and to
other forms of multiple viewing window fireplaces such as see through
fireplaces having
two windows on opposite side of the fire, and two opaque end panels, and to
corner
fireplaces, such as indicated as 290 in Figure 11 (whether left or right
handed) having
viewing windows on two adjacent sides such as may meet at a common corner; or
all
around fireplaces in which all sides permit viewing of the fire. Such all
around fires can
be produced in four sided configurations as well as six or eight-sided shapes.
The
invention can be employed with direct-vent fireplaces, or with conventional
draft
fireplaces that draw in ambient room air and exhaust combustion products to
the exterior
environment. It may be employed with enclosed flame displays in a sealed
direct vent unit,
a B-vent unit, retro-fit gas burning fireplace inserts, and open display gas
fireplaces in
which the flame is not enclosed behind viewing panels, but is open, or visible
through a
steel mesh grill or spark curtain.
An alternative gas fireplace display assembly 300 includes a set of simulated
solid
fuel elements 310, in the nature of a set of simulated wood firelogs, shown in
Figure 8.
Set 310 includes a lower front log 312, a lower rear log 314, an upper central
log 316,
front near and far end cross logs 318 and 320, and top cross logs 322 and 324.
These
simulated logs are positioned atop stepped pan burners 330 and 332 in
positions to
interact with the flame pattern produced by those burners. That interaction
includes
impingement of flames on visible face portions of logs 312, 314, and 316.
These logs,
being made of soft ceramic material, will tend to glow when heated in this
manner.
Further, the flame port arrays of burners 330 and 332 are such that generally
larger flames
CA 02262867 1999-02-23
19
are formed in the gaps 334 and 336 between the respective lower and center
logs. In
alternative embodiments, such as those in which higher density ceramic logs,
such as for
example concrete logs, are used, it may be desired to avoid flame impingement,
yet still
maintain the visual interaction of flames flickering in front of log elements.
S
Gas fireplace assembly 300 is shown in cross section in Figure 9. Burners 330
and
332 sit upon support structure in the nature of a burner tray 340, for
location upon firebox
floor 342. Each burner 330 or 332 includes an outward lower burner manifold
344 in the
form of a ported flat pan burner section for providing flames to the simulated
log elements
nearer to the respective window and an upper, inward burner manifold 346
stepped
upwardly and inwardly from lower burner manifold 344, for providing flames to
the more
inwardly located simulated display elements. Burners 330 and 332 are supported
by left
and right hand angle brackets 350 and 352 affixed to tray 340.
Burner 330 has a body in the form of a sheet metal shell. It has inlets 354
and 356,
through which burner can receive combustible gases from a conventional gas
control and
gas train (not shown). Burner 330 has an array of gas ports that permit the
egress of
combustible gas therefrom in the form of a gas jets such that, when lit, the
jets produce
a flame pattern in the neighborhood of the simulated fire display of log set
310. Pilot 358,
suitably concealed in the midst of the simulated fire display, log set 310,
and only partially
visible in Figure 9, provides the initial ignition source. Arrays of flame
carry-over ports
(not visible) carry the flame between upper and lower portions of burners 330
and 332.
Lower front log 312 has an upper, predominantly dark brown bark simulating
region 360, a cream or beige region 362 to simulate a split wood surface, a
blackened
region 364 to simulate a charred surface, and cut end regions 366 and 368 on
either end
to give the appearance of sawn firewood. Each of regions 360, 362, 364, 366,
and 368
has a texture and color pattern appropriate to its role. Other features of log
312 include
pickup points for alignment on burner 330, and locating pads for logs 318 and
320. These
features, locating points on burners 330 and 332, grilles, andirons and other
common
fireplace features are known. A simulated grating 372 is provided having
upturned tines
166. The base of tines 166 and standoffs 376, or equivalent, sit under log 312
to give an
air space 378 above burner 330. Lower rear log 314 and central log 316 each
have
corresponding bark simulating, split wood simulating, blackened, and sawn
regions.
CA 02262867 1999-02-23
It is intended that only portions of logs 312, 314 and 316 lying within their
respective blackened regions be subjected to sufficient heating to cause
glowing. Each
blackened region 364 has protruding pads 380 which, when glowing, provide an
appearance not unlike that of glowing charcoal. As can be seen in the front
view of log
5 set 310 provided in Figure 8, blackened region 364 has a larger visible area
than blackened
region 382 of central log 316. Region 382 is at least partially hidden from
view behind log
312. The visual attractiveness of the fire is thought to be enhanced by
encouraging
relatively large flames to rise in gaps 334 and 336 to give the appearance of
an ample
blaze, and by enhancing the orange and red glow given off' by the relatively
larger and
10 more prominent blackened region 364 of log 312 (or 314, as the case may
be). This
enhancement can include altering the air-fuel mix and using a different
pattern of
apertures, in the upper portion of burners 330 and 332 as compared to their
lower
portions.
1 S Loose heapings of simulated charcoal embers are indicated generally as 386
and
388, and serve not only to create a suitable fire-like appearance, but also to
conceal
supporting angle brackets 350 and 352. These heapings are located generally
below
grating 372, and between grating 372 and either of windows 390 and 392.
Simulated
embers 386 and 388 are made of soft ceramic material. In alternative
embodiments
20 they can also be made of spun glass, rock wool, vermiculite or other
similar materials
as noted above. Heating elements 394 and 396 extend through heapings 386 and
388,
and are connected to sockets as described above and interact with the
simulated ember
materials to produce a glowing appearance, as described above.
Different arrangements of fireplace elements are possible. In some instances,
particularly those in which no simulated gratework is employed, the fireplace
will tend
to appear as a wood fire resting on a bed of embers. That is, the simulated
ember
materials will tend to appear to underlie at least a portion of the solid fuel
simulating
elements, (that is, as illustrated as firelogs). When the simulated solid fuel
elements are
raised above the firebox floor, and gratework is shown, the simulated ember
materials
may tend to be placed to appear to underlie the gratework, as if having fallen
between
the bars. Alternatively, whether in a single viewing window display or in a
multi-
viewing window display, simulated ember materials can be placed to lie
generally in
front of, and at a lower height than, the simulated firelogs, or gratework,
such that the
CA 02262867 1999-02-23
21
simulated ember materials lie in the foreground of the display, as seen by the
viewer,
and the firelogs are seen (relative to the simulated ember materials) in the
background.
For example, in the embodiments illustrated in Figures 2 and 8, the viewer can
be
presented with a glowing bed of embers in the foreground of the display, and a
flame
array set against a background of logs. The simulated ember materials can be
of the
type suitable for heating to provide the desired glowing ember appearance,
while at
the same time serving to assist in the concealment of one or more of such
items as the
gas burner, gas control, electric heating element, and support bracket
structure.
In the embodiment of Figures 12a and 12b a simulated solid fuel element, in
the nature of a simulated flrelog is indicated as 400. For convenience of
description it
is shown having a generally similar appearance to that of firelog 312
described above.
This appearance is arbitrarily chosen, and a different appearance could be
chosen
without departing from the principles of the invention. Firelog 400 differs
from firelog
312 in that firelog 400 has two pockets, 402 and 404 and heating elements 406
and 408
mounted, or embedded in pockets 402 and 404 respectively. Pockets 402 and 404
are
generally similar, so that a description of cross-section '12b-12b' of pocket
402 serves
to describe the nature of pocket 404 as well.
Pocket 402 has a lip 410 that at least partially hides heating element 406 so
that
it is not directly visible by a person viewing log 400 from the direction
indicated by
arrow ' A' . Lip 410 need not be very thick in cross section to perform this
function,
and can have an irregularly profiled edge to approximate a burnt portion of a
log. A
camouflage, or shielding element, such as a baffle , in the nature of
simulated
grillwork, could also be used for this purpose.
Relatively loose ember materials 412 of appropriate colour and shape, are
mounted within pocket 402 to appear to form a portion 414 of an exposed face
416 of
log 400. Ember materials 412, like the glowing ember materials described
above, are
made of materials suitable for heating to an incandescent state, or can be
arranged,
typically with interstitial gaps, relative to a glowing source to give a
glowing
appearance. In use, the glowing effect of ember materials 412 is to meld with
the
general appearance of face 416 of firelog 400. Ember materials 412 can be held
in
place by gravity, can be bonded in place, or can be mechanically retained by
other
CA 02262867 1999-02-23
22
means, such as an interference fit. Connector sockets 418, 420, 422 and 424
protrude
from a hidden side, in the example illustrated, the bottom, of firelog 400 to
permit
heating elements 406 and 408 to be connected to mating connectors, in the
nature of
mating sockets, of an electrical circuit or circuits.
S
A fireplace display assembly can have more than one log, like firelog 400,
that
is equipped with one or more electrical heating elements. A fireplace display
can have
a combination of heating elements, such as element 170, for heating loose
embers
heaped on floor 32, and firelogs, such as firelog 400 having embedded
electrical
heating elements. In a further elaboration of the principles of the invention,
the heating
elements can be operated at different settings, whether high, low or medium,
or on a
continuously variable range, to produce a dull red glow, a brighter orange
glow, a
nearly white appearance, or, in the case of a continuously variable element,
some other
intermediate effect.
1S
Further, each heating element, whether a firebox floor ember heating element
like element 170 or 172, or a firelog heating element like element 406 or 408
can be
connected to be separately operable to cause a portion of the firelog to
appear to glow,
either on a manual control, on a set timed schedule, or on a micro-processor
controlled
random schedule to permit greater unpredictable variability of the glowing
appearance.
Figure 13 shows a schematic illustration of a control system 430 for a multi-
element fireplace, such as fireplace assembly 300. A Microprocessor 432
receives
inputs from a user operable control panel, 434, a timer 436, a non-volatile
memory
2S 438, a device having a random output, such as a random number generator
440, and
a self test fault input source 442. Microprocessor 430 controls outputs to
four burner
gas flow control valves 444, 446, 448, and 450, and to four electric heater
element
controls, such as potentiometers 452, 454, 456 and 458. The number of burner
and
electric heating elements could be larger or smaller, four each are chosen for
the
purposes of illustration.
In operation, the user can choose to set a manual override 460 to 'manual' ,
in
which case the user can operate fireplace 300 in an 'On-Off' manner.
Alternatively,
if placed in a microprocessor controlled operation mode, a self test fault
from source
CA 02262867 1999-02-23
23
442 can also turn the system off, and extinguish the fire. Self test can
include sensing
to monitor for electrical or logic faults, or can test for over-temperature,
excess
accumulation of fuel in the firebox, excess carbon monoxide or carbon dioxide,
or for
insufficient draft.
If in microprocessor control mode, a user can use a user programmable
interface, in the nature of a keypad of control panel 434, to key in an
operating profile
in the nature of a time versus heating element or burner element schedule.
Alternatively, the user can select automatic operation using a permanent
operating
schedule placed in non-volatile memory 438, typically a Programmable Read-Only
Memory (PROM), and the fire will operate according to a preset program to vary
the
appearance of the fire over time by varying the output signals sent to valves
444, 446,
448 and 450 or to potentiometers 452, 454, 456, or 458. An operator may be
given the
choice of one preset schedule to be chosen from among several. In a further
alternative, the user can select an automated schedule having a random input
function,
as from random number generator 440, to permit microprocessor 300 to generate
an
operating schedule. In this way rather than repeating a known schedule over
and over,
as in the case of a fixed memory, the appearance of the display can vary each
time it
is used in a pattern not previously seen.
In a further alternate variation shown in Figures 14a, and 14b, a simulated
firelog 500, is drawn for convenience as having the same general form as log
400. In
Figure 14a, the face of firelog 500 is shown in a partial, or scab section to
reveal
internal features. In the scab section, firelog 500 is shown having a heating
array 502
made of heating wires 504 of smaller diameter than heating elements 406 and
408.
Array 502 can be arbitrarily formed in a desired contour to follow features of
face 506
of log 500. That is, the wires of array 502 run generally side-by-side and are
to be
electrically connected in parallel. When log 500 is cast, array 502 is
captured in the
casting as an insert, at a relatively shallow depth behind front face 506, of
the order
of one, two or a very few millimetres. It may be advantageous to cast array
502 within
a higher density, more thermally conductive ceramic pallet 508 than the soft
ceramic
used for the majority of the body of log 500, given the high insulative
quality of soft
ceramic material generally. The ceramic chosen for pallet 508 should be
suitable for
heating to a glowing temperature, a possible material being a plaque burner
ceramic
CA 02262867 1999-02-23
24
material. Array 502 has connectors 510 and 512 similar to connectors 418 and
420
noted above. In other alternative embodiments it would be possible to have
more than
one such heating array like array 502, formed to some other portion of log
500, such
that separate portions of the log can be caused to glow either together or on
different,
varying schedules over time. It is not necessary that the individual heating
wires have
round cross-section, a ribbon or generally rectangular section may also be
possible.
In another alternative embodiment as shown in Figure 15, a firelog 550 is
again
represented in the same general form as firelog 400 previously described.
However,
firelog 550 has a glowing faceplate portion 552, formed with a surface
resembling a
charred log surface, made of a heatable carbide of other material, such as
silicon
carbide, that can be heated to a glowing condition when provided with electric
current.
Faceplate portion 552 can be formed of a large number of discrete silicon
carbide
elements, each formed to approximate the appearance of charcoal pieces 554 on
the
face of a log, and each having a relatively thin cross-section. Faceplate
portion 552
seats within a cast log body 556 such as can be made of soft ceramic or other
suitable
log simulating material.
Various embodiments of the invention have now been described in detail. Since
changes in and or additions to the above-described best mode may be made
without
departing from the nature, spirit or scope of the invention, the invention is
not to be
limited to those details, but only by the appended claims.
