U.S. patent application number 12/147934 was filed with the patent office on 2009-12-31 for atmospheric burner for gas log fireplace producing stage combustion and yellow chemiluminescent flame.
This patent application is currently assigned to EMPIRE COMFORT SYSTEMS, INC.. Invention is credited to Syed Mohammad Noman.
Application Number | 20090325114 12/147934 |
Document ID | / |
Family ID | 41447892 |
Filed Date | 2009-12-31 |
United States Patent
Application |
20090325114 |
Kind Code |
A1 |
Noman; Syed Mohammad |
December 31, 2009 |
Atmospheric Burner for Gas Log Fireplace Producing Stage Combustion
and Yellow Chemiluminescent Flame
Abstract
An atmospheric burner assembly for a gas log fireplace comprises
a mixing chamber adapted to receive gas from a gas supply and mix
gas and air therein. The burner assembly also comprises a manifold
adapted to receive gas from a gas supply. The burner assembly also
has a burner with a first port communicating with the mixing
chamber and a second port communicating with the manifold. The
second port is adapted to generate a flame pattern that is embedded
within the first port. When installed in the fireplace, the burner
assembly combusts pure gas at the second port for rich combustion
and a mixture of gas and air at the first port for lean combustion,
thereby promoting stage combustion at the burner assembly and
producing a yellow chemiluminescent flame.
Inventors: |
Noman; Syed Mohammad;
(Belleville, IL) |
Correspondence
Address: |
THOMPSON COBURN LLP
ONE US BANK PLAZA, SUITE 3500
ST LOUIS
MO
63101
US
|
Assignee: |
EMPIRE COMFORT SYSTEMS,
INC.
Belleville
IL
|
Family ID: |
41447892 |
Appl. No.: |
12/147934 |
Filed: |
June 27, 2008 |
Current U.S.
Class: |
431/354 ;
126/512 |
Current CPC
Class: |
F23D 14/02 20130101;
F23D 2900/21004 20130101; F23C 2201/20 20130101; F24C 3/006
20130101; F23C 6/02 20130101; F23D 14/62 20130101; F23D 14/58
20130101; F23D 14/82 20130101 |
Class at
Publication: |
431/354 ;
126/512 |
International
Class: |
F23D 14/62 20060101
F23D014/62; F24B 1/18 20060101 F24B001/18 |
Claims
1. An atmospheric burner assembly for a gas log fireplace
comprising: a mixing chamber adapted to receive gas from a gas
supply and mix gas and air therein; a receiver adapted to receive
gas from a gas supply; and a burner with a first port communicating
with the mixing chamber and a second port communicating with the
receiver, the second port being adapted to generate a flame pattern
that is embedded with a flame pattern of the first port, wherein
when installed in the fireplace, the burner assembly combusts gas
at the second port for rich combustion and a mixture of gas and air
at the first port for lean combustion, thereby promoting stage
combustion at the burner assembly and producing a yellow
chemiluminescent flame.
2. The atmospheric burner assembly of claim 1, wherein: the first
burner port surrounds the second burner port.
3. The atmospheric burner assembly of claim 1, wherein: the mixing
chamber comprises a generally planar burner plate spaced from a
burner assembly bottom support.
4. The atmospheric burner assembly of claim 3, wherein: the first
burner port comprises slots formed in a pattern in the burner
plate.
5. The atmospheric burner assembly of claim 4, wherein: the second
port burner port comprises an opening in a tube communicating with
the receiver arranged within the slot pattern.
6. The atmospheric burner assembly of claim 1, wherein: the
receiver is disposed in the mixing chamber.
7. The atmospheric burner assembly of claim 1, wherein: the
receiver is configured to draw between about 5% and 30% of gas
supplied to the burner assembly.
8. A gas log fireplace comprising: a gas supply; a mixing chamber
in communication with the gas supply adapted to mix gas and air
therein; a receiver in communication with the gas supply; and a
burner with a first port communicating with the mixing chamber and
a second port communicating with the receiver, the second port
being adapted to generate a flame pattern that is embedded within a
flame pattern generated by the first port, the burner combusting
gas at the second port for rich combustion and a mixture of gas and
air at the first port for lean combustion, thereby promoting stage
combustion and producing a yellow chemiluminescent flame at the
burner.
9. The fireplace of claim 8, wherein: the first burner port and the
second burner port are co-axially aligned.
10. The fireplace of claim 8, wherein: the mixing chamber comprises
a generally planar burner plate spaced from burner assembly bottom
support.
11. The fireplace of claim 10, wherein: the first port comprises
slots formed in a pattern in the burner plate.
12. The fireplace of claim 11, wherein: the second port comprises
an opening in a tube communicating with the receiver arranged
within the slot pattern.
13. The fireplace of claim 8, wherein: the receiver is disposed in
the mixing chamber.
14. The fireplace of claim 8, wherein: the receiver is configured
to draw between about 5% and about 30% of gas supplied to the
burner.
15. The fireplace of claim 8, further comprising: a valve
positioned between the gas supply and the receiver.
16. The fireplace of claim 14, further comprising: a user control
operatively connected to the valve adapted to selectively control a
level of gas flow from the gas supply to the receiver.
17. The fireplace of claim 16, wherein: the user control is adapted
to supply to the receiver between 0% and about 30% of the gas
supplied to the burner.
18. A gas log fireplace comprising: a gas supply; a burner assembly
comprising a generally planar burner plate spaced from a burner
bottom support and forming a mixing chamber receiving gas from the
gas supply and mixing the gas with air therein, the burner assembly
having a manifold disposed in the mixing chamber receiving gas from
the gas supply, the burner plate having a plurality of slot
patterns formed therein, each slot pattern being spaced from
another slot pattern in the burner plate, slots in the slot pattern
communicating with the mixing chamber and combusting the mixture of
gas and air for lean combustion, the manifold having a plurality of
tubes extending therefrom to areas adjacent the slot patterns, the
tubes having openings arranged within the slot pattern, the
openings of the tubes combusting pure gas for rich combustion, the
burner assembly generating stage combustion and producing a yellow
chemiluminescent flame.
19. The fireplace of claim 18, wherein: the manifold is configured
to draw between about 5% and about 30% of gas supplied to the
burner assembly.
20. The fireplace of claim 18, further comprising: a valve
positioned between the gas supply and the manifold.
21. The fireplace of claim 20, further comprising: a user control
operatively connected to the valve adapted to selectively control a
level of gas flow from the gas supply to the manifold.
22. The fireplace of claim 21, wherein: the user control is adapted
to supply to the manifold between 0% and about 30% of the gas
supplied to the burner assembly.
Description
BACKGROUND
[0001] The disclosure relates generally to gas burner systems, and
specifically to gas burner systems for open flame display, such as
gas logs for fireplaces, and even more specifically gas burner
systems for vent free or direct vent applications.
BRIEF DESCRIPTION OF THE DRAWINGS
[0002] FIG. 1 is a top view of an embodiment of the burner assembly
comprising a top plate with six dual port burners with a portion of
the top plate being partially broken away to show further detail of
an interior of the burner assembly that includes a mixing chamber
with ceramic pellets disposed therein that supplies a gas-air
mixture to lean flame burner ports of the dual port burners of the
burner assembly and a receiver comprising a manifold assembly that
delivers gas to rich flame burner ports of the dual port burners of
the burner assembly;
[0003] FIG. 2 is a perspective view of an underside of a top plate
of the burner assembly of FIG. 1, showing additional detail of the
manifold assembly used to deliver gas to the rich flame burner
ports of the dual port burners of the burner assembly; and
[0004] FIG. 3 is a schematic diagram of a fireplace in which the
burner assembly is installed showing additional detail of valves
and orifices used in connection with the manifold and receiver to
vary the flow of gas to the lean and the rich flame burner ports of
the dual port burners of the burner assembly.
DETAILED DESCRIPTION
[0005] Referring to the figures, a gas burner assembly is generally
designated by the reference numeral 10 in FIG. 1, and generally
comprises a box shape with top plate 12 and a base 14 spaced from
the top plate to form a mixing chamber 16 therebetween. Attached to
the periphery of the base 14 are front and back walls 18,20 that
partially enclose the burner assembly leaving the left and right
sides open for piping and an air intake associated with the burner
assembly. It should be appreciated that the directions top, bottom,
left, right, front, and back are used merely for illustrative
purposes as they correspond to the general orientation shown in the
drawings, and the directions top, bottom, left, right, front, and
back are not intended to be limiting in any sense to a specific
orientation or structure. Preferably, the top plate 12 and the base
14 are generally flat and the walls 18,20 are perpendicular to the
top plate and the base so that the burner assembly 12 takes the
shape of a rectangular solid for ease of construction. However,
sloped walls, a curved base, or other convenient shapes could be
used as desired to form the burner assembly 10. Preferably, the top
plate, front and back sides, and base are made of metal or other
material that can endure prolonged intense heat as well as the
frequent cycling between temperature extremes. Ceramic materials
may also be used for forming the top plate, base, and/or front and
back sides.
[0006] As shown in the FIGS. 1 and 2, six dual port burners 30 are
located in the burner assembly top plate 12, as will be described
in greater detail below. A pilot for ignition of the burner
assembly may be provided, and carryover holes 34 are arranged in
lines extending across the top plate in a random pattern to carry
the flame after ignition across the burner assembly top plate 12 to
ignite the dual port burners 30. As best shown in FIG. 3, a log
support, grate, or other convenient support 36 may be disposed
above the top plate 12 for supporting log materials 38, and
material 40 resembling burning embers, such steel or rock wool or
spun glass, is preferably piled under the grate or log support
around and atop the burner top plate 12 over the carry-over holes
34. The grate may also be formed integral with the burner assembly
top plate and the logs held in place with pins extending from the
top plate.
[0007] A gas delivery system 50 (FIG. 3) connects the burner
assembly 10 to an external combustible gas source, including but
not limited to natural gas and propane ("LP"). The gas delivery
system 50 carries gas (or feed) from the external source through a
main cut-off valve 52 to a "tee" connection 54 where a first
portion of the gas is directed to a receiver 56 for eventual
delivery to rich flame burner ports associated with each dual port
burner 30, and second portion of the gas is delivered to the mixing
chamber 16 via a main gas manifold 58 to be mixed with air for
eventual delivery to the carry over holes 34 and lean flame burner
ports associated with each dual port burner 30. In the mixing
chamber 16, the gas and air is mixed in order to produce a lean
flame zone with highly efficient combustion and reduced emissions
of NO.sub.x and CO. Preferably, the air to gas ratio/mixture
developed in the mixing chamber 16 to be combusted in the lean
flame zone is between about five (5) percent and about thirty (30)
percent more than the stoichiometric air to gas ratio mixture
needed for complete combustion. The rich flame zone at the rich
flow burner has an air to gas ratio/mixture that is theoretically
or about zero. During the combustion process at the dual port
burner 30, the average air to gas ratio/mixture reaches a fuel rich
environment creating higher theoretical flame temperature and
taller flames. The higher theoretical flame temperature produces
more heat. The receiver 56 preferably receives between about five
(5) and about thirty (30) percent of the gas flow while the main
gas manifold 58 receives between about seventy (70) and ninety-five
(95) percent of the gas flow. The percentage of gas flow may be
regulated by orifices 60. Valves, orifices and/or the pipe size
associated with each of the receiver (including tube branches 68
extending from the spider manifold, as will be explained below) and
main gas manifold may also be used in combination to regulate and
apportion flow to the main gas manifold, and the receiver and the
tube branches. As shown by example in FIGS. 1 and 2, the receiver
56 preferably comprises a spider manifold with the tube branches 68
extending therefrom to each of the dual port burners 30. The
receiver 56 is preferably disposed under the burner top plate 12 in
the mixing chamber 16. The main gas manifold may connect to a side
of the burner assembly and discharge directly into the mixing
chamber 16. Valves and controls associated with the valves may be
disposed under the bottom support to protect them from the heat of
the fireplace. While the gas delivery system 50 is shown in FIG. 3
as a single pipe with the "tee" connection 54 to the receiver 56
and the main gas manifold 58, it is understood that multiple pipes
could be used to deliver the gas to the receiver or main gas
manifold or mixing chamber, and that the pipe(s) could enter the
burner assembly through the front and/or back sides, or even the
base for connection to the receiver or main gas manifold.
[0008] The burner assembly mixing chamber 16 may contain ceramic
pellets 70 (FIG. 1) comprising a conglomeration of particles
sufficiently disparate in size and/or shape to form a loosely
packed permeable barrier for the gas to flow through. The ceramic
pellets 70 may completely fill the mixing chamber 16 or only a
portion of it. The irregularity of the ceramic particles diffuses
the gas so that the gas is mixed and dispersed in the mixing
chamber prior to being directed to the carry over holes 34 and/or
the lean flame burner port(s) of the dual port burners 30, where it
is ignited and combusted. The use of ceramic pellets in the mixing
chamber reduces the occurrence of flash-back or flame extinction
problems when the burner system is turned on or off. Because of the
diffuse gas flow that reaches the burners at different rates and
times, the combustion flames at the burners "dances" much like a
woodburning flame.
[0009] Each dual port burner 30 of the burner assembly comprises a
lean flame burner port 80 and a rich flame burner port 82. As shown
by example in FIGS. 1 and 2, the lean flame burner port 80
comprises a plurality of slots in the top plate arranged in a
pattern communicating with the mixing chamber, and the rich flame
burner port 82 comprises a distal end of the tube branch 68
extending from the receiver or spider manifold 56. The rich flame
burner port 82 combusts pure gas to produce a rich flame, i.e., a
yellow flame, and solid state C.sub.2. The lean flame burner port
80 combusts the gas/air mixture from the mixing chamber 16 and the
C.sub.2 produced by the rich flame zone thereby producing a yellow
flame and providing an aesthetically pleasing simulation of wood
burning in a conventional fireplace. Additionally, burning the
C.sub.2 and the soot particle, which were produced in the rich
flame zone, inside the lean flame zone increases the heat output of
the fireplace unit, as a higher theoretical flame temperature is
achieved for the fireplace unit. Further, burning the C.sub.2 and
the soot particle, which were produced in the rich flame zone,
inside the lean flame zone, tends to increase flame height.
Preferably, the rich flame burner port 82 produces a flame pattern
that is embedded within a flame pattern produced by the lean flame
burner port 80, thus allowing the C.sub.2 produced by the rich
flame burner port to be introduced directly into the flame pattern
of the lean flame burner port, thereby reducing potential emissions
and excess soot deposits. As shown in FIG. 1, the rich flame and
lean flame burner ports 82,80 of each dual port burner 30 are
aligned such that the lean flame burner port surrounds and is
co-axially aligned with the rich flame burner port. The distal end
of the tube branch 68 may be positioned in the center of the slot
pattern of the lean flame burner port as one method of embedding
the rich flame burner port flame pattern within the lean flame
burner port flame pattern. The opening forming the rich flame
burner port may be dimensioned to correspond to a #55 drill size.
It should be appreciated that the rich flame burner port may also
be spaced from and/or arranged at an angle relative to the lean
flame burner port in such a way that the flame pattern produced by
the rich flame burner port impinges or is embedded within the flame
pattern produced by the lean flame burner port. To increase flame
height, each dual port burner may be provided with a flame venturi
84 comprising an upstanding wall enclosing the lean flame burner
port. As shown in FIG. 3, the flame venturi extends around the
periphery of the slot pattern of the lean flame burner port. Holes
86 may be provided in the upstanding wall of the flame venturi to
draw additional combustion air into the lean flame burner port 80
and to accelerate the flame upward from the burner 30.
[0010] As shown in FIG. 3, a valve 90 may be positioned in the gas
supply preferably between the "tee" connection 54 and the receiver
or spider manifold 56 to control a rate of gas flow to the rich
flame burner ports 82 and thus the rate of rich flame combustion.
The valve 90 may throttle the flow or secure the flow, as may be
desired. The valve 90 may be manually actuated or operatively
connected to a control 92 that automatically sets the position of
the valve for a specific operation or function. The control 92 may
comprise a microprocessor unit on the fireplace that integrates and
controls some or all of the functions the fireplace. The control 92
may also be operated via remote controls associated with the
fireplace. For instance, to assist in the generation of a "dancing
flame," the control 92 may dynamically cycle the valve 90 to vary
the flow rate of gas to the receiver or spider manifold 56. The
control's dynamic cycle may be based upon a timer, or ambient
conditions in the area in which the gas-log fireplace is situated,
for instance, room temperature or sound. The control 92 may also be
operatively connected to or interfaced with a thermostatic control
associated with the gas-log fire place for automatic or manual
temperature control based upon ambient conditions. The control may
also be selectively controlled by the user, as may be desired, to
increase, decrease "yellow" flame height, change flame color,
change temperature, or to suspend the "yellow" flame appearance by
stopping rich flame combustion. The control 92, and/or other valves
(not shown) provided in addition to the orifices 60 in the any of
the connections to the main gas manifold and spider manifold, may
be used for fine tuning of the combustion process for a specific
configuration at set-up or installation of the fire place, for
instance, to fine tune operations for direct vent and vent-less
configurations, high altitude installations, and/or LP and natural
gas applications.
[0011] Use of stage combustion increases the heat output of the
fireplace for a given gas usage. For instance, by producing higher
theoretical flame temperature, stage combustion generates the heat
of a 38,000 BTU unit while only expending the gas of a 28,000 BTU
unit, thus allowing smaller units to be used and/or conservation of
gas.
[0012] It should be appreciated the dual port burner may comprise
an arrangement other than the plate arrangement shown in the
drawings. For instance, the dual port burner may comprise coaxially
aligned tubes with the lean flame port comprising an outer tube
communicating with the mixing chamber and the rich flame port
comprising an inner tube disposed in the outer tube communicating
with the receiver. As a further example as shown in FIGS. 1, 2, and
3, lean flame burner port may comprise an tube extension 100
projecting away from the top plate in register with a hole 102 in
the top plate 12 that communicates with the mixing chamber, and the
spider manifold tube branch 68 may be lengthened to extend through
the top plate inside the tube extension 100 so that the distal ends
of the tube extension and tube branch are elevated from the top
plate thereby allowing combustion and flame generation to be
elevated relative to the top plate. As shown by example in FIG. 3,
the tube extension 100 and lengthened tube branch 68 may extend
through an aperture 104 in a log of the log set 38 to simulate
burning logs in positions elevated from the top plate.
[0013] While specific embodiments have been described in detail in
the foregoing detailed description and illustrated in the
accompanying drawings, those with ordinary skill in the art will
appreciate that various modifications and alternatives to those
details could be developed in light of the overall teachings of the
disclosure. Accordingly, the particular arrangements disclosed are
meant to be illustrative only and not limiting as to the scope of
the invention, which is to be given the full breadth of the
appended claims and any and all equivalents thereof.
* * * * *