Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
The present invention generally relates to a fireplace heater which
includes a forced air circulating structure in the form of tubular heater
members associated with manifolds, a grate, a reflector plate, a front log
retaining plate, a top heat retaining place, a cover forming a closure between
the log retaining plate and the top heat retaining plate, a forced air draft
arrangement and optional side or end plates with all of the structure being
arranged for easy assembly and disassembly for storage and shipment in a com-
pact condition and including interchangeable components to enable installation
in various types of fireplaces.
Many efforts have been made to more efficiently utilize the heat
produced by burning logs or other fuel in a fireplace. The simpliest type of
device is the provision of generally U-shaped tubes interconnected to form a
grate for the combustible logs with the lower ends of the tubes providing cold
air inlet and the upper ends of the tubes providing hot air outlets with both
the upper and lower ends of the tubes extending toward the front of the
fireplace in order to discharge hot air into the space im~ediately outwardly
of the fireplace. Due to the limitations of air circulation in such devices,
a lower manifold was connected with the lower ends of the tubes and a circulat-
ing fan communicated therewith to provide forced air circulation from floor
level up through the tubes and out of the front ends of the tubes which
provide further distribution of hot air outwardly of the fireplace, but such
air was discharged at the upper portion of the fireplace, thus leaving the
space adjacent floor level of a room or the like relatively cold. In our
prior U.S. patent No. 3,930,490, issued January 6, 19761 for Fireplace
Heater there is disclosed a structure for more effective heat exchange
with the combustion products formed by the combustion of logs or other
fuel in the fireplace and a structure for taking in cold air at floor
level, forcing it through heat exchange tubes and then discharging it
outwardly of the fireplace adjacent floor level for less air temperature
stratification in the room in which the fireplace is located. In addition,
the following patents disclose heaters associated with fireplaces for
either forced or gravitational air circulation:
U.S. Pat. Nos: 737,381 - Aug. 25, 1903
1,313,085 - Aug. 12, 1919
1,608,745 - Nov. 30, 1926
1,640,771 - Aug. 30, 1927
1,783,140 - Nov. 25, 1930
2,052,643 - Sep. 1, 1936
2,131,7~3 - Oct. 4, 1938
10 2,702,030 - Feb. 15, 1955
' 2,828,078 - Mar. 25, 1958
3,001,521 - Sep. 26, 1961
3,240,206 - Mar. 15, 1966
3,269,383 - Aug. 30, 1966
3,452,737 - July 1, 1969
3,635,211 - Jan. 18, 1972
3,945,369 - Mar. 23, 1976
4,018y209 - Apr. 19, 1977
British Pat. No. 900,622 - July 11, 1962.
While all of the prior devices operate for the purposes intended,
more efficient heat transfer at less cost is desirable.
An object of the present invention is to provide a fireplace heater
utilizing tubes or pipes interconnected to provide a fireplace heater with a
grate mounted thereon for supporting logs or other combustible material with
the lower ends of the pipes being interconnected by a manifold having an air
circulating fan communicating therewith and certain of the pipes communicated
therewith, together with an upper heating chamber connecting and communicating
with all of the pipes so that cold air from the floor will be discharged
from the fan into the manifold upwardly through certain of the pipes and
into the upper heating chamber and then downwardly through the remainder
of the pipes which project forwardly -through the manifold for discharge
of hot air adjacent floor level.
Another aspec-t of -the invention is to provide a fireplace
heater in acoordance with the preceding object, -together with a heat
reflector plate positioned on top of the rear edge of the grate and
engaged with the heat chamber to form a closure for the rear of the
fireplace heater and reflecting heat forwardly from the fireplace.
A further aspect of the invention is to provide a fireplace
heater in accordance with the preceding objects/ together with a heat
retaining plate hingedly connected to the heat cham~er but in vertically
spaced overlying relation thereto to guide combustion products into more
intimate and more efficient heat exchange relationship to the heating
chamber and other components of the fireplace heater.
Still another aspect of the invention is to provide a
fireplace heater in accordance with the preceding objects, together with
a front log retaining plate and a cover plate extending between the front
log retaining plate and the forward edge of the heat retaining plate
to form a front closure for the fireplace heater which can be easily
removed to enable insertion of logs or other combustible material
into the fireplace heater.
A still further aspect of the invention is to provide a
fireplace heater in accordance with the preceding objects, together
with rem~vable side or end plates which can be optionally used and
which form a closure for a portion of the vertical height of either or
both ends of the fireplace heater.
Yet another aspect of the invention is to provide a fireplace
heater in accordance with the preceding objects, in which the air
circulating fan is provided with a forced draft arrangement for supplying
combustion supporting air to the fireplace heater.
Yet further objects of the invention reside in the construc-
tion of the ireplace heater with components which are easily assembled
at the side of installation, thereby enabling the device to be stored
and shipped in a compact
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condition and with the components being interchangeable in such a manner to
enable various installational requirements to be effectively satisfied with
the fireplace heater efficiently utili~ing the heat produced by the combustible
logs and effectively discharging the heated air into a room, air circulating
ducts, or to any other desired location.
In this invention, the fireplace grate becomes a high temperature
firebox, burns the gases low inside the grate, similar to a coal fire, turning
the wood into hot, long burning coals with temperatures to 1400F. plus. The
grate has a long life far exceeding the well-known cast iron grate that feeds
oxygen up from the bottom and through the fire. With our grate, the oxygen
feeds up from the bottom traveling along the outside of the front portion of
grate then over the top of the fire and to the back of the fireplace then
traveling upward and out. Wood is completely consumed to a white powdery
ash, with a very small ash build up requiring very infrequent clean out even
when the fireplace is burned continuously The heat retaining plate placed on
an angle, guides the combustive gases upwardly to the back of the fireplace,
into the fireplace throat, thereby assuring that no gases spill outwardly into
the room.
Figure 1 is a perspective view of the fireplace heater of the
present invention with the fireplace being diagrammatically illustrated to
show the relationship of the present invention to an existing fireplace.
Figure 2 is a vertical sectional view taken substantially upon a
plane passing along section line 2--2 of Fig. 1 illustrating the specific
structural details of the fireplace heater.
Figure 3 is a sectional view, on an enlarged scale, illustrating
the manifold structure and the relationship of the air inlet and air
exhaust pipes.
Figure ~ is a detailed sectional view of the heat chamber
illustrating the heat retaining plate in elevated position with a pivotal
prop securing the plate in this position to enable large logs to be placed
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into the fireplace heater.
Figure 5 is a fragmental plan view of the forced draft device
disposed along one side of the fireplace heater.
Figure 6 is a sectional view of the forced air draft device
illustrating further structural details thereof.
Referring now specifically to the drawings, the fireplace heater of
the present invention is generally designated by reference numeral 10 and is
installed in a conventional fireplace opening 12 having the usual damper arm
(not shown) and rests on the hearth 14 inwardly of a closure device 16 for the
fireplace opening 12 which may be in the form of folding or sliding transparent
glass doors or the like, the details of which are not shown, with the lower
end of the closure member 16 including an air panel 18 to be described in
detail hereinafter. The fireplace heater 10 is disposed with the rear portion
thereof to the rear wall 20 of the fireplace, all of which represents conven-
tional fireplace structure with the dimensional characteristics of the fire-
place heater varying depending upon the dimensions of the fireplace in which
the fireplace heater is installed.
The fireplace heater 10 includes a grate for receiving logs or other
combustible fuel with the grate generally being designated by numeral 24 and
including two sets of grate pipes including air inlet grate pipes 26 and air
exhaust grate pipes 28 which are disposed in spaced parallel relation to each
other and include a generally horizontally disposed lower portion, an upwardly
curved rear portion and a forwardly and upwardly inclined upper portion as
illustrated in Fig. 2. All of the grate pipes 26 and 28 are covered by a
grate 30 as illustrated in Fig. 2 with the grate 30 setting on the grate pipes
26 and 28 and conforming to the shape and configuration of the forward and
curved portion of the grate pipes. Interconnecting the forward end portion of
the grate pipes 26 and 28 is a horizontally disposed lateral manifold 32 with
the air inlet grate pipes 26 being communicated with the interior of the
manifold 32 and the air exhaust grate pipes 28 extending through the manifold
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32 and terminating in forwardly projecting ends 34 which also project through
the air panel 18 so that the terminal forward ends of the projecting ends 34
of the air exhaust grate pipes 28 terminate substantially flush with the
forward surface of the air panel 18 under the closure member 16 for discharge
of heated air forwardly along the hearth or floor level. Air inlet is provided
to one end of the manifold 32 by an air circulating fan 36 having a pipe or
conduit 38 communicating with one end of the manifold 32. As illustrated, the
air circulating fan 36 and the conduit 38 are disposed outwardly of the
fireplace and may be oriented on the hearth 14 with the conducit 38 including
appropriate elbows or other fittings so that it extends through an opening 40
in the air panel 18 and extends into and connects with an end cap 42 having a
fitting 44 to which the conduit 38 is connected with the end cap 42 being
releasably secured to the manifold 32 by screws or the like. The end cap 42
may be interchanged with a solid end cap 46 on the opposite end of the manifold
32 to enable the air circulating fan 36 and the conduit 38 to be optionally
oriented to either the left or right side of the fireplace heater.
The upper ends of of the grate pipes 26 and 28 are rigidly connected
to and communicated with a horizontally disposed, transversely extending heat
chamber 48 which has removable end caps 50 thereon corresponding to the end
caps 46 or 42 so that conduits can be connected thereto, if desired, for
discharge of heated air forwardly from the fireplace at any elevation desired
or into duct works for conveying the heated air to any desired location. The
heat chamber includes rigid nipples 52 along the bottom thereof which are
rigidly affixed to the grate pipes 26 and 28 in any suitable manner such as by
using set screws, or the like, which may also be used to connect manifold 32
to the pipes to enable disassembly and assembly of the components thereby
enabling storage and shipment when in a compact knocked down condition. The
heat chamber 48 communicates all of the grate pipes so that air entering the
heat chamber from the air inlet grate pipes 26 will exit the heat chamber
through the air exhaust grate pipes 28 for discharge of the heated air through
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the terminal projectincJ ends 34 at floor level. Any sui-table numker of
gra-te pipes may be employed with alterna-te pipes being inlet and exhaust
pipes or, if desired, a larqer numker of the exhaus-t pipes may be utilized
to provide for expansion of the heated air during passage through the
pipes and heating chamber. Depending upon the na-ture and size oE the
fire, heated air may be discharged into the room at floor level at
approximately 500F. For additional efficiency and heat, end tubes can
be added to either end of the heat chamber 48 by utilizing an end cap 42
rather than an end cap 50 with such end tubes or conduits including elbows
or any other Eittings which can be swiveled in any direction for piping
heated air into any desired area.
This unit is a stable unit and is supported from the hearth
by the lower surface of the manifold 32 and downwardly projecting
supporting legs 54 adjacent the juncture between the horizontal portion
and the upwardly curved portion of the pipes. Thus, this unit Q n be
installed in the fireplace and constitutes a stable, self-supported unit
and may be used with the air panel 18 when a closure member 16 is
employed. If a different type of closure member is employed for the
fireplace opening, in SQme instances, the air panel 18 may not be used
- or may be modified. The air panel 18 is a rectangular, hollow filler
member between the lower edge of the closure member 16 and the hearth
14 and may be secured to the lower end of the closure member 16 in any
suitable manner with preformed openings formed therein or openings may
be easily cut therein to receive the projecting ends 34 of the air
exhaust grate pipes 28. The air circulating fan 36 may be cf conventional
construction, with the source of the air being the surrounding space
or room or, if desired, air may be taken from the exterior of the
house especially when a portion of this air will be used to support
combustion through a forced draft assembly described hereinafter,
thereby reducing heat 105s Up the chimney opening 22 due to the draft
conditions induced within the interior of the house by the discharge
of combustion products.
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A reflector plate 56 extends transversely in Eront of the upper
portions of the grate pipes 26 and 28 and the lower edge of the heat chamber
with the upper edge of the reflector plate 56 being received behind a downward-
ly extending p]ate or flange 58 rigidly fixed to the front surface of the heat
chamber 48 and extending downwardly therefrom in slightly spaced relation to
the upper end portions of the grate pipes 26 and 28, so that the upper edge of
the reflector plate 56 may be placed behind the plate 58 and moved upwardly so
that rearwardly inclined tabs 60 formed in the lower edge of the plate 56 may
pass over the top edge of the grate 30 and the reflector plate 56 then moved
downwardly slightly so that the upper edge of the grate 30 is received between
the tabs 60 and the bottom edge of the reflector plate 56 as illustrated in
Fig. 2. The tabs 60 may be simply formed by lancing the lower edge of the
reflector plate 56 and the tabs rearwardly deflected in a manner well-known in
the art so that reflector plate 56 will be retained in position but can be
easily assembled and disassembled when desired. The reElector plate will
reflect heat forwardly from the fireplace heater so that radiated heat will be
discharged into the room or space in which the fireplace heater is used.
A heat retaining plate 62 extends transversely of the fireplace
heater substantially throughout the heat chamber 48 with the plate 62 extending
normally forwardly and downwardly from the heat chamber 48 but the plate 62 is
spaced vertically from the top surface of the heat chamber 48 so that combus-
tion products may pass between the heat retaining plate 62 and the heat chamber
48. To provide for this spaced relationship, the rearward edge of the heat
retaining plate 62 is pivotally attached to the top surface of the heat
chamber 48 by hinge structures 64 which are in spaced relationship to each
other and which space the heat retaining plates 62 from the heat chamber 48.
The hinge structures 64 are located at the rear edge of the heat chamber 48
and the rear edge of the plate 62 and the forward edge of the heat chamber 48
is provided with a plurality of upwardly projecting stop pins 66 which engage
the undersurface of the heat retaining plate 62 to maintain the heat retaining
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plate 62 in generally spaced parallel relation to the top surface of the heat
chamber 48 as illustrated in Fig. 2 but with the forward edge of the heat
retaining plate extending forwardly beyond the heat chamber 48 and terminating
in a downwardly extending narrow flange 68 at its forward edge. This structure
enables the heat retaining plate 62 to move from its normal operative position
as illustrated in Fig. 2 to an elevated position illustrated in Fig. 4 to
enable placement of relatively large logs into the fireplace heater. In order
to temporarily retain the heat retaining plate 62 in its open or elevated
position as illustrated in Fig. 4, a pivotal prop 70 is attached to the
undersurface of the plate 62 in a manner such that it will fall due to gravity
into an inclined position with the lower end setting on heating chember 48 to
prop the heat retaining plate 62 in its open or elevated position when it is
elevated to a position such that the prop 70 will assume a vertical position
so that subsequent release of the plate 62 will cause the prop 70 to slide
down and forwardly along the top surface of the heat chamber 48 and rest
thereon. When it is desired to lower the plate 62 to its operative position,
a conventional poker may elevate the plate and be engaged with the prop 70
adjacent its lower end and the lower end of the prop 70 may then be moved to
its folded or collapsed position with the heat retaining plate 62 then being
lowered to its operative position.
The forward portion of the grate 30 is upwardly inclined as at
72 so that it passes above the manifold 32 with the upwardly inclined
portion 72 terminating in a downturned flange 73 and a pair of upstanding
brackets 74 are rigidly secured thereto with the lower ends of the brackets
74 being inclined as at 76 and attached in any suitable manner to the
inner surface of the upwardly inclined portion 72 of the grate 30.
Attached to the brackets 74 is a log retaining plate 78 secured to the
outer surface of the brackets 74 by fasteners 80 or the like which serves
to retain logs, sparks and coals on the grate 30. As illustrated in Fig.
2, the space between the top edge of the log retaining plate 78 and the
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forward edge of the heat retaining plate 62 provides access to the interior
of the fireplace heater and this space is closed by a cover plate 82 which
has spaced tabs 84 formed in the lower edge thereof by lancing the lower
edge of the cover plate 82 and deflecting the tabs 84 so that the downwardly
opening notches formed thereby will be engaged over the top edge of
the log retaining plate 78. The top edge of the cover plate 82 rests
against the downwardly inclined flange 68 of the heat retaining plate 62
which is inwardly of the top edge of the log retaining plate 78 so that
gravity will retain the cover plate in position. The cover plate is
provided with a loop 86 on its outer surface adjacent the center upper
edge thereof which Eacilitates the insertion of the poker hook, or the
like, therein to lift the cover plate upwardly away from the heat retaining
plate 62 and the log retaining plate 78 so that it can be set aside when
logs or other combustible fuel is being added to the fireplace heater.
Thus, with the heat retaining plate 62 in its operative position and the
cover plate 82 in position, the logs or other combustible fuel supported
on the grate 30 will effectively heat all the components and the combustion
products will pass between the 'neat chamber 48 and the heat retaining
plate 62 with the space for such passage being designated by reference
numeral 88 which assures efficient heat transfer between the adjacent
surface areas of the furnace heater and the air passing through the heat
chamber 48. The structural components may be constructed of any suitable
material having requisite strength characteristics and requisite
characteristics to resist deterioration from high temperatures.
The end of the fireplace heater may be partially closed with an
end plate or end plates 90 which conform with the inner surfaces of the grate
30 and log retaining plate 78. The end plate 90 is retained in position on
the grate by two or more projecting tongues along the edges thereof which are
received in slot-like openings 92 formed in the side edge portions of the
grate 30 with the two tongues and slots being spaced longitudinally and
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generally in surfaces at the rean~ard curved portion of the grate and either
in the horizontal portion adjacent the forward edge thereof or in the inclined
portion 72 of the grate 30.
A forced draft assembly 94 is disposed alongside of the end of the
fireplace heater adjacent the end edge of the grate 30 in generally parallel
relation thereto and is in the form of a pipe 96 connected to the conduit 38
extending from the air circulating fan 36 into the manifold 32. The pipe 96
is connected to the conduit 38 adjacent its point of connection with the
manifold 32 and is connected thereto in any suitable manner with the opposite
end of the pipe 96 being plugged or closed so that the interior of the pipe is
provided with air under pressure from the circulating fan 36. The pipe or
tube 96 is provided with a plurality of longitudinally spaced holes 98 therein
which are selectively opened and closed by a sliding sleeve 100 having corres-
ponding holes 102 for selective registry with the holes 98. Any suitable
means such as a pin and slot arrangement 104 interconnects the pipe 96 and the
sleeve 100 to limit the longitudinal movement of the sleeve and to retain the
sleeve 100 from becoming angularly displaced. An elongated operating rod 106
is connected to the sleeve 100 and extends outwardly generally in a parallel
relation to the pipe 96 and terminates in an operating knob 108 outwardly of
the manifold 32 and outwardly of the air panel 18 if the air panel is being
used. A supporting prop 110 is attached to the inner end of the pipe 96 for
support of the same from the hearth with the support leg or prop 110 being
reversible so that the forced air draft assembly 94 may be used either to the
left or to the right of the fireplace heater. Also, the connection between
the operating rod 106 and the sleeve 100 is reversible in a similar manner so
that the operating rod 106 will be disposed at the bottom inner portion of the
air draft pipe 96 when it is placed at the opposite side of the fireplace
heater. Our prior patent ~o. 3,930,490 also discloses a forced draft similar
in function to draft assembly 94.
It is pointed out that the fireplace heater as disclosed fully
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contains the fire thus providing for a longer burning, low flame fire with
heat being prevented from flowing directly up and out the chimney. Rather,
heat must Elow under the heat retaining plate and over and around the top
heating chamber thus effectively extracting heat from the combustion products
before these gases exit through the space provided between the top heating
chamber and the heat retaining plate. Thus, high efficiency and intense heat
is obtained since the cold air flows in and upwardly into the heating chamber
and then downward for discharge into the room with the circulating air extract-
ing heat from the combustion products throughout its passage through the
fireplace heater. The removable cover plate 82 and the hinged heat retaining
plate 62 enables large logs to be effectively loaded into the fireplace
heater. The cover plate 82 may be lifted and easily handled, even when hot,
with a conventional poker and the same poker may be used for lifting the front
edge of the heat retaining plate 62 to move it to its elevated position and
also used to move the prop to collapsed position to lower the heat retaining
plate 62 after logs have been placed into the fireplace heater. The interchange-
able end caps on the manifold and heat chamber enable the forced air circulat-
ing fan and forced draft assembly to be installed at either side of the
fireplace heater. Also, end caps with nipples may be provided at either or
both ends of the heat chamber to which conduits are connected for conveying
heated air into any desired area. The optional end plates and optional forced
draft assembly enables not only retention of the heat and fire but also
adequate supply of combustion supporting air. If a forced draft is not
desired or necessary, the usual draft at the lower end of the closure member
may be employed for supplying combustion supporting air and the forward
portion of the grate may be provided with a conventional slide draft to
enable inflow of combustion supporting air into the area containing the logs
or other combustible fuel. The heat reflector plate 56 prevents heat from
being absorbed by the back wall of the fireplace and reflects radiant heat
towards the front of the fireplace. Also, the construction of the various
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components enables assembly and disassembly thereof so that the components can
be stored and shipped in a knocked down condition and then easily set up at
the site of installation. For example, the pipes 26 and 28 may be connected
to the manifold and chambers by a telescopic arrangement between short nipples
and the ends of the pipes and a single screw extending through the nipples
into engagement with the pipes, so that the plates are detachable from the
tubes and detachable from each other.
The structure of the grate, forced draft and heat retainer is of one
standard depth and is placed to the very back of the Eireplace and is so de-
signed that the back curvature of the heater allows for conventional construc-
tion of the fireplace having back wall tapering inwardly to the fireplace
throat. Varying depths of fireplaces are provided for by simply varying the
length of air tubes which are furnished to allow for the greatest depth
fireplaces and which can easily be cut to desired length in the field. The
grate simply sets on and over all the heater tubes, the grate being formed of
one standard shape.
The grate is a very important and integral functioning part of the
fireplace heater by providing a firebox that extracts the energy and heat to
the highest degree of efficiency, adding a great measure of safety by providing
a low, hot burning fire, prevents danger of sparks or logs rolling out or into
glass doors, allows large logs to be used for continuous burning, allows for
efficiently burning newspapers. The gra~e will outlast cast iron grates and
can easily be repaired when burn through does occur.
