U.S. patent application number 13/372239 was filed with the patent office on 2012-08-16 for multi-stage decorative burner.
Invention is credited to Mike THIELVOLDT.
Application Number | 20120208133 13/372239 |
Document ID | / |
Family ID | 46637155 |
Filed Date | 2012-08-16 |
United States Patent
Application |
20120208133 |
Kind Code |
A1 |
THIELVOLDT; Mike |
August 16, 2012 |
MULTI-STAGE DECORATIVE BURNER
Abstract
The invention provides systems and methods for multi-stage
burners. The burner may accept a variable input fuel stream, which
may be divided into a plurality of output fuel streams. The fuel
stream may be divided by a pressure-actuated flow separator that
may distribute an increasing amount of fuel to a secondary flow
stream as the input flow rate of the input fuel stream increases.
One or more of the output streams may be conditioned to provide a
desired flame characteristic. The multi-stage burners may be
decorative burners, and may be used for theatrical displays or
other fire displays.
Inventors: |
THIELVOLDT; Mike; (Hayward,
CA) |
Family ID: |
46637155 |
Appl. No.: |
13/372239 |
Filed: |
February 13, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61443222 |
Feb 15, 2011 |
|
|
|
Current U.S.
Class: |
431/8 ; 431/280;
431/284; 431/355 |
Current CPC
Class: |
F23C 6/047 20130101;
F23C 2900/06043 20130101; F23D 2207/00 20130101; F23D 23/00
20130101; F23D 14/045 20130101; F23D 14/84 20130101; A63J 5/023
20130101 |
Class at
Publication: |
431/8 ; 431/280;
431/284; 431/355 |
International
Class: |
F23D 23/00 20060101
F23D023/00; F23D 14/62 20060101 F23D014/62; F23D 14/10 20060101
F23D014/10 |
Claims
1. A multi-stage burner with variable output, comprising: a fuel
input stream; a proportioning system that divides the fuel input
stream into multiple fuel output streams; a passage that introduces
air into at least one of the fuel output streams; and an outlet
that combines the fuel output streams in a common atmospheric
combustion zone.
2. The burner of claim 1 wherein the proportioning system changes
the relative proportions of fuel flowing in the fuel output streams
with respect to the total fuel flowing through the burner.
3. The burner of claim 2 wherein the fuel output streams include a
primary fuel output stream and a secondary fuel output stream, and
the proportioning system diverts an increasing proportion of the
total fuel to the secondary with increasing total fuel flow.
4. The burner of claim 3 wherein the proportioning system comprises
a spring-loaded relief that blocks fuel from flowing to the
secondary fuel output stream until a threshold upstream pressure is
exceed, thereby causing the relief to open, permitting fuel to
enter the secondary stream.
5. The burner of claim 3 wherein the proportioning system comprises
a spring-loaded relief movable between (a) a closed position that
blocks most fuel from flowing to the secondary fuel output stream,
and (b) an open position that permits an increased amount of fuel
to flow to the secondary fuel output stream, and a channel that
circumvents the relief to allow fuel to flow to the secondary fuel
output stream when the relief is in the closed position.
6. The burner of claim 3 further comprising an inspirator that is
configured to draw air into the primary fuel output stream through
an air passage.
7. The burner of claim 3 wherein the outlet is configured such that
the primary fuel output stream exits through a smaller cylindrical
tube that is co-axial with a larger cylindrical tube that conveys
the secondary fuel output stream.
8. The burner of claim 7 wherein the smaller cylindrical tube
extends past the plane of the larger cylindrical tube.
9. The burner of claim 3 further comprising a third pilot stream
that is used to ignite the flame fed by the primary and secondary
fuel output streams.
10. The burner of claim 3 further comprising a diffuser in the
secondary fuel output stream to uniformly slow the fluid flow.
11. The burner of claim 3 further comprising a laminizer configured
to divide the secondary fluid output stream into a series of
smaller channels.
12. The burner of claim 3 wherein the secondary fuel output stream
has a larger cross-sectional area at its outlet than the primary
fuel output stream at its outlet.
13. A method for producing a flame comprising the following steps:
controlling an input flow rate of a fuel input stream; separating
the flammable gas input stream into multiple output streams,
wherein a first output stream carries the majority of the fuel
output flow for a first range of input flow rates and a second
output stream carries the majority of the fuel output flow for a
second range of input flow rates; conditioning at least one output
stream to obtain desired flame properties at different input flow
rates; and introducing the first and second output streams into a
common atmospheric combustion region.
14. The method of claim 13 wherein the conditioning of the at least
one output stream includes using a diffuser to uniformly slow the
fluid flow.
15. The method of claim 13 wherein the conditioning of the at least
one output stream includes using one or more laminizer to divide
the at least one output stream into a series of smaller
channels.
16. The method of claim 13 wherein said separating is performed by
a spring-loaded relief that is in a first position for the first
range of input flow rates and in a second position for the second
range of input flow rates.
17. A method for producing a flame comprising the following steps:
controlling the flow rate of a flammable gas input stream;
diverting some of the flammable gas input stream through an orifice
to a primary output stream; sending remaining flammable gas from
the flammable gas input stream to a secondary output stream via a
relief valve that opens when the pressure upstream of the relief
valve is above a specific design pressure; and introducing both
streams into a common atmospheric combustion region.
18. The method of claim 17 further comprising entraining air into
the primary output stream using an inspirator.
19. The method of claim 17 further comprising conditioning the
secondary output stream to be a substantially uniform, laminar
flow.
20. The method of claim 17 wherein the secondary output stream
surrounds the primary output stream.
Description
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/443,222, filed Feb. 15, 2011, which application
is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates in general to gaseous fuel burners.
More particularly this invention may relate to gaseous fuel burners
for decorative applications with regulated air entrainment that
produce a luminous, smokeless flame.
BACKGROUND OF THE INVENTION
[0003] In the field of special effects, real flames are often
employed to achieve a powerful visual impact on live audiences.
Devices called flame projectors emit flames that often exceed 30
feet in height in sequence with musical transitions or other
dramatic events. Flame effects currently available for theatrical
applications are capable of producing flames that are either on or
off, but not variable. Other theatrical equipment, such as
directional lights and LEDs can vary the intensity of their output
over a wide range, allowing a much greater variety of visual
impressions, images and moving patterns than would be possible with
binary on/off control of these devices. In order to generate more
powerful visual effects using fire, an improved flame effect is
needed to vary its output over a wide range similar to lighting
devices. A further need exists for flame effects with widely
variable outputs that could generate images and patterns with
enhanced richness and variety as compared to on/off flame effects
currently available.
[0004] Atmospheric burners, including those used in flame effects,
sometimes pre-mix fuel with some air and introduce the mixture into
a combustion region where additional ambient air mixes with the
fuel and the mixture burns in a stable manner. Practically,
traditional decorative flame effects are limited to emitting
fuel-rich flammable mixtures in order to generate luminous flames
that contain light-radiating carbon particles. However, a flame
that is excessively rich will also produce unsightly black smoke
and heightened levels of CO, an undesirable pollutant. Therefore, a
need exists for a burner for a practical flame effect that produces
a fuel-air mixture with a fuel-air ratio that lies within a narrow
acceptable range.
[0005] Turbulence aids the mixing of fuel and air in an atmospheric
combustion region, which reduces the amount of pre-mixed air that
is necessary to avoid creating visible smoke.
[0006] Emitting gas to the combustion region at higher velocities
generates greater turbulence. Consequently, the desirable fuel-air
premix ratio for a flame effect changes depending on the velocity
of gasses exiting the burner. For a burner with a fixed
cross-sectional area at its outlet, if the fuel throughput
increases, the velocity also increases. Accordingly, a need exists
for a variable-output flame effect that is capable of varying
either the fuel-air ratio of the mixture it emits, or the
cross-sectional area of the burner exit, or both, in response to
the varying throughput to maintain soot-free, luminous
combustion.
[0007] Therefore there is a clear and persistent need for a burner
that can produce a flame that is stable, soot-free and luminous
over a wide range of sizes.
SUMMARY OF THE INVENTION
[0008] The invention provides systems and methods for multi-stage
decorative burners. Various aspects of the invention described
herein may be applied to any of the particular applications set
forth below or for any other types of flame effects. The invention
may be applied as a standalone system or method, or as part of an
integrated display package, such as a theatrical fire display, or
any other fire display. It shall be understood that different
aspects of the invention can be appreciated individually,
collectively, or in combination with each other.
[0009] In accordance with an aspect of the invention, a burner for
a decorative flame effect may be provided that can accept a wide
range of fuel throughput rates while maintaining a luminous,
smokeless flame.
[0010] In some embodiments, a burner for a decorative flame effect
may support a fully-attached, stable flame with a widely-variable
flame height.
[0011] A burner that produces a luminous smokeless flame over a
wide range of output rates may comprise a proportioning system that
can divide the input fuel into two or more output streams, one or
more passages that can introduce air into one or more of the fuel
output streams, and a burner outlet geometry that may combine the
multiple output streams to form a single flame.
[0012] The separate flow paths may be constructed to condition the
fluid streams flowing through them to improve the aesthetic
properties of the flame such as, by reducing turbulence, increasing
flow uniformity, or controlling velocity. By separating the fuel
flow into multiple streams, and conditioning each stream
separately, using flow path geometry, a designer can manipulate the
characteristics of the flame at various heights with greater
flexibility than would be possible using a single flow path. The
geometry of each fuel flow path may be designed to achieve specific
air/fuel ratios, flow velocities and turbulence levels.
[0013] The proportioning system can be designed to send a greater
fraction of the total flow to a certain flow path as the total flow
increases. Thus, the flame properties may be increasingly dominated
by the flow characteristics of that certain fuel stream as the
total flow increases. Conversely, the flame properties may be
dominated by the flow characteristics of a different fuel stream as
the total flow decreases. This progressive blending of two or more
fluid streams with different flow properties can be used to build a
burner capable of maintaining a flame with desirable aesthetic
properties over a wide range of flame sizes.
[0014] Other goals and advantages of the invention will be further
appreciated and understood when considered in conjunction with the
following description and accompanying drawings. While the
following description may contain specific details describing
particular embodiments of the invention, this should not be
construed as limitations to the scope of the invention but rather
as an exemplification of preferable embodiments. For each aspect of
the invention, many variations are possible as suggested herein
that are known to those of ordinary skill in the art. A variety of
changes and modifications can be made within the scope of the
invention without departing from the spirit thereof.
INCORPORATION BY REFERENCE
[0015] All publications, patents, and patent applications mentioned
in this specification are herein incorporated by reference to the
same extent as if each individual publication, patent, or patent
application was specifically and individually indicated to be
incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The novel features of the invention are set forth with
particularity in the appended claims. A better understanding of the
features and advantages of the invention will be obtained by
reference to the following detailed description that sets forth
illustrative embodiments, in which the principles of the invention
are utilized, and the accompanying drawings of which:
[0017] FIG. 1A is a high-level depiction of a multi-stage burner
with two stages provided in accordance with an embodiment of the
invention.
[0018] FIG. 1B is a high-level depiction of a multi-stage burner
with more than two stages provided in accordance with an embodiment
of the invention.
[0019] FIG. 1C is a high-level depiction of another possible
configuration for a multi-stage burner with more than two stages
provided in accordance with an embodiment of the invention.
[0020] FIG. 2 is a block diagram of a multi-stage burner.
[0021] FIG. 3 is a cross-sectional view of a multi-stage burner in
accordance with an embodiment of the invention.
[0022] FIG. 4 is an additional cross-sectional view of a
multi-stage burner.
[0023] FIG. 5 provides an exploded view of a multi-stage burner
provided in accordance with an embodiment of the invention.
[0024] FIG. 6 shows an example of a flame element provided in
accordance with an embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] While preferred embodiments of the invention have been shown
and described herein, it will be obvious to those skilled in the
art that such embodiments are provided by way of example only.
Numerous variations, changes, and substitutions will now occur to
those skilled in the art without departing from the invention. It
should be understood that various alternatives to the embodiments
of the invention described herein may be employed in practicing the
invention.
[0026] A multi-stage burner may be provided in accordance with an
embodiment of the invention. The multi-stage burner may be a
luminous, smokeless gas burner. The burner may be used for a
decorative flame effect, and may accept a wide range of fuel
throughput rates while maintaining a luminous, substantially
smokeless flame. The burner may support a fully-attached, stable
flame with a widely-variable flame height. The burner may allow the
flame height to vary rapidly. In some embodiments, the burner may
be used for theatrical effects, or other fire displays.
[0027] FIG. 1A is a high-level depiction of a multi-stage burner
with two stages provided in accordance with an embodiment of the
invention. The multi-stage burner may include one or more of the
following: a fuel supply 100, a fuel rate control 101, a flow
separator 102, a primary flow path 103a, a secondary flow path
103b, and a flame combination region 104.
[0028] Fuel may flow from the fuel supply 100. The fuel supply may
have a finite amount of fuel, or may have a relatively unlimited
supply of fuel. In some embodiments, the fuel supply may be a tank
or other container. In other embodiments, the fuel supply may be a
utility or may be conveyed from a very large fuel source. In some
embodiments the fuel may be propane, natural gas, hydrogen,
acetylene, alcohol, gasoline, diesel, oil, or other flammable fuel.
The fuel may be a gaseous fuel, liquid fuel, or any other fluid
fuel.
[0029] In some embodiments a fuel rate control 101 may be provided
that may control the fuel flow rate from the fuel supply 100. In
some embodiments, the fuel rate control may be a proportional
valve. The fuel rate control may control the overall flow of fuel
from the fuel supply. The fuel rate control may vary or maintain
the fuel flow rate of the fuel input stream to the burner. The fuel
rate control may be located locally or remotely from the fuel
supply. In some embodiments, the fuel rate control may control the
amount of fuel flowing from the fuel supply, while in other
embodiments, the fuel rate control may only control whether fuel is
flowing from the fuel supply or not.
[0030] A flow separator 102 maybe in fluid communication with the
fuel rate control 101 and/or the fuel supply 100. The flow
separator may separate the fuel into two or more separate flow
paths. In some embodiments, the flow separator may separate the
fuel into a primary flow path 103a and a secondary flow path 103b.
In some embodiments, both the primary and secondary flow paths may
convey fuel to the combustion region 104. In some embodiments, the
flow separator may be a relief valve. The flow separator may
separate the fuel depending on total fuel flow rates. For example,
in some embodiments, the primary flow path may convey more of the
fuel for low total fuel flow rates. The secondary flow path may
carry a progressively greater portion of the total fuel as the
total fuel flow rate increases. The secondary flow path may convey
more of the fuel for high total fuel flow rates. Thus, the
properties of the flame may be dominated by the primary stream when
the flame is small, but transition to being dominated by the
secondary stream as the flame gets larger. Thus, in some
embodiments, depending on the total fuel flow rate, the fraction of
fuel distributed between the primary and secondary flow paths may
change. The fraction of fuel distributed to the secondary flow path
versus the primary flow path may increase as the total fuel flow
rate increases. A flow separator may separate a fuel input steam
into multiple output streams, wherein a first output stream carries
the majority of the fuel output flow for a first range of input
flow rates, and a second output stream carries the majority of the
fuel output flow for a second range of input flow rates.
[0031] FIG. 1B is a high-level depiction of a multi-stage burner
with more than two stages provided in accordance with an embodiment
of the invention. The multi-stage burner may include one or more of
the following: a fuel supply 110, a fuel rate control 111, a flow
separator 112, a first flow path 113a, a second flow path 113b, a
third flow path 113c, up to any number of flow paths 113d and a
flame combination region 114.
[0032] A flow separator 112 maybe in fluid communication with the
fuel rate control 111 and/or the fuel supply 110. The flow
separator may separate the fuel into two, three, four or more
separate flow paths. A flow separator may separate fuel into N
separate flow paths, where N is a whole number greater than 1. The
separate flow paths are preferably not in fluid communication with
one another after the flow separation.
[0033] In some embodiments, the flow separator 112 may separate the
fuel into a first flow path 113a, a second flow path 113b, a third
flow path 113c, and possible additional flow paths 113d. In some
embodiments, all of the flow paths (e.g., first, second, and third
flow paths) may convey fuel to the combustion region 114. In some
embodiments, the flow separator may be a relief valve. In some
embodiments, a single flow separator may be used to separate the
fuel into multiple flow paths. Alternatively, a plurality of flow
separators may be used to separate the fuel into multiple flow
paths.
[0034] The flow separator may separate the fuel depending on total
fuel flow rates. For example, in some embodiments, the first flow
path may convey more of the fuel for low total fuel flow rates. The
second flow path may carry a progressively greater portion of the
total fuel as the total fuel flow rate increases. The third flow
path may carry a progressively greater portion of the total fuel as
the total fuel flow rate increases even further. For instance, the
second flow path may carry a progressively greater portion of the
total fuel when the total fuel flow rate approaches or exceeds a
first threshold, and the third flow path may carry a progressively
greater portion of the total fuel when the total fuel flow rate
approaches or exceeds a second threshold that is higher than the
first threshold. Thus, the properties of the flame may be dominated
by the first stream when the flame is small, but transition to
being dominated by the second stream as the flame gets larger, and
transition to being dominated by the third stream as the flame gets
larger still. This may be true for any number of flow paths with
each subsequent flow path receiving a greater portion of the total
fuel as the total fuel rate goes higher and higher. Thus, in some
embodiments, depending on the total fuel flow rate, the fraction of
fuel distributed between flow paths may change. The fraction of
fuel distributed to the second flow path versus the first flow path
may increase as the total fuel flow rate increases. The fraction of
fuel distributed to the third flow path versus the second or first
flow path may increase as the total fuel flow rate increases
further. This may occur for any subsequent flow paths.
[0035] FIG. 1C is a high-level depiction of another possible
configuration for a multi-stage burner with more than two stages
provided in accordance with an embodiment of the invention. The
multi-stage burner may include one or more of the following: a fuel
supply 120, a fuel rate control 121, a first flow separator 122a, a
second flow separator 122b, a first flow path 123a, a second flow
path 123b, up to any number of flow paths 123c, and a flame
combination region 124.
[0036] A first flow separator 122a maybe in fluid communication
with the fuel rate control 121 and/or the fuel supply 120. The
first flow separator may separate the fuel into two or more
separate flow paths. For example, a first flow separator may
separate the fuel into a first flow path 123a and fuel that is
further separated by a second flow separator 122b. The second flow
separator may separate the fuel received into two or more separate
flow paths. In one example, the second flow may separate the fuel
into a second flow path 123b and a third flow path. In another
example, the second flow separator may separate the fuel into a
second flow path and fuel that is further separated by a third flow
separator. In a burner assembly, N-1 flow separators may be
provided that may separate fuel into N separate flow paths, where N
is a whole number greater than 1. Any number of flow separators may
be daisy chained to create any number of separate flow paths. The
separate flow paths are preferably not in fluid communication with
one another after the flow separation.
[0037] In some embodiments, all of the flow paths (e.g., first,
second, and third flow paths) may convey fuel to the combustion
region 124. In some embodiments, the one or more flow separators
may be a relief valve. In some embodiments, a plurality of flow
separators may be used to separate the fuel into multiple flow
paths.
[0038] The flow separators may separate the fuel depending on total
fuel flow rates. For example, in some embodiments, the first flow
path may convey more of the fuel for low total fuel flow rates. The
second flow path may carry a progressively greater portion of the
total fuel as the total fuel flow rate increases. The third flow
path may carry a progressively greater portion of the total fuel as
the total fuel flow rate increases even further. For instances, the
second flow path may carry a progressively greater portion of the
total fuel when the total fuel flow rate approaches or exceeds a
first threshold, and the third flow path may carry a progressively
greater portion of the total fuel when the total fuel flow rate
approaches or exceeds a second threshold that is higher than the
first threshold. A first flow separator may apportion a greater
amount or fraction of total fuel to a second flow path over the
first flow path as the total fuel flow rate increases. In some
embodiments, a second flow separator may apportion a greater amount
or fraction of fuel to a third flow path over the second flow path.
This may or may not affect the amount of fuel apportioned to the
first flow path. Thus, the properties of the flame may be dominated
by the first stream when the flame is small, but transition to
being dominated by the second stream as the flame gets larger, and
transition to being dominated by the third stream as the flame gets
larger still. This may be true for any number of flow paths with
each subsequent flow path receiving a greater portion of the total
fuel as the total fuel rate goes higher and higher. Thus, in some
embodiments, depending on the total fuel flow rate, the fraction of
fuel distributed between flow paths may change. The fraction of
fuel distributed to the second flow path versus the first flow path
may increase as the total fuel flow rate increases. The fraction of
fuel distributed to the third flow path versus the second or first
flow path may increase as the total fuel flow rate increases
further. This may occur for any subsequent flow paths.
[0039] The total fuel flow may be divided into any number of fuel
flow paths. The fuel may be divided at one point, or may be divided
in multiple stages in a daisy-chained fashion, or any combination
thereof. Any description herein of a two-stage burner may also be
applied to multi-stage burners with any number of flow paths, and
vice versa.
[0040] FIG. 2 is a block diagram of a multi-stage burner. A
multi-stage burner assembly may include one or more of the
following: a fuel supply, a proportional valve, a relief valve, a
primary flow path, a secondary flow path, and a combining outlet.
In some embodiments, the primary flow path may include an
inspirator with an air inlet. In some embodiments, the secondary
flow path may include a diffuser and a laminator.
[0041] In some embodiments, a proportional valve may determine the
amount of fuel flow from the fuel supply. A proportional valve can
be adjusted to control whether any fuel is flowing, or the degree
of fuel flow. The proportional valve may control the total rate of
fuel flow from the fuel supply.
[0042] A relief valve may be in fluid communication with fuel that
flows past the proportional valve. The relief valve may separate
the total fuel into two or more separate flow paths. For example,
the relief valve may separate the total fuel into a primary flow
path and a secondary flow path. The primary and secondary flow
paths are preferably not in fluid communication with one another
after the flow separation. Alternatively, they may be brought into
fluid communication. The primary and secondary flow paths may be
combined in a common atmospheric combustion zone.
[0043] In some embodiments, the relief valve may separate the fuel
depending on total fuel flow rates. For example, in some
embodiments, the primary flow path may convey more of the fuel for
low total fuel flow rates. The secondary flow path may carry a
progressively greater portion of the total fuel as the total fuel
flow rate increases. In some embodiments, when the total fuel flow
rate is beneath a particular threshold, all or most of the fuel may
be directed to the primary flow path with none or very little of
the fuel being directed to the secondary flow path. Thus, the
properties of the flame may be dominated by the primary stream when
the flame is small, but transition to being increasingly dominated
by the secondary stream as the flame gets larger.
[0044] Thus, depending on the total fuel flow rate, the fraction of
fuel distributed between the primary and secondary flow paths may
change. The fraction of fuel distributed to the secondary flow path
versus the primary flow path may increase as the total fuel flow
rate increases. In some embodiments, the fraction of the fuel
distributed to the secondary flow path may be zero until the total
fuel flow rate exceeds a threshold value. The fraction of the fuel
distributed to the secondary flow path may be zero until pressure
exerted on the relief valve exceeds a threshold pressure. Once the
total fuel flow rate exceeds the threshold, increasing amounts of
fuel may flow to the secondary flow path. In some embodiments, the
amount of fuel that flows to the secondary flow path may or may not
have a linear relationship with the increase in the total fuel flow
rate. Alternatively, the secondary path flow may have any other
relationship with the total fuel flow rate. In some alternate
embodiments, there is no threshold value, and there may be a
positive fraction of fuel in the secondary path as long as there is
total fuel flow.
[0045] The primary or secondary flow path may be conditioned to
obtain desired flame properties at different input flow rates. One
or more stream may be conditioned to affect whether the flow is
laminar or turbulent, speed of output stream, air to fuel content
of the stream, or any other property. In one example, a primary
flow path may be conditioned to have different flame properties
than a secondary flow path.
[0046] In some embodiments, the primary flow path may preferably
have an inspirator with one or more air inlets. The air may be able
to mix with the fuel in the primary flow. Alternatively, there may
be no air inlet in the primary flow path. In some embodiments there
is no air inlet for the secondary flow path. Alternatively, there
may be an air inlet for the secondary flow path.
[0047] In some embodiments, the secondary flow path may preferably
have a diffuser and a laminizer The diffuser and laminizer may be
positioned in series. For example, the fuel may first flow through
the diffuser and then through the laminizer. The diffuser may
reduce the non-uniformities in fluid velocity, thereby resulting in
a more even flame. The laminizer may reduce the turbulence of the
stream, which may slow the mixing with air in the combustion
region, resulting in a taller, and therefore more visually
prominent flame.
[0048] FIG. 3 is a cross-sectional view of a multi-stage burner in
accordance with an embodiment of the invention. The multi-stage
burner may include a pilot, a primary passage, and a secondary
passage. In some embodiments, fuel may be provided to the burner
through a gas inlet 1. The fuel may be distributed to a manifold
body 2. The manifold body may accept the fuel through the gas
inlet.
[0049] An interior of a pilot may be in fluid communication with
the manifold body 2. In some embodiments, a fuel channel or any
other passageway may connect the manifold with the interior of a
pilot base 3. A pilot base may be connected to a pilot fuel/air
passage 19 via a pilot orifice 4. In some embodiments, the pilot
orifice may be a channel or passageway. The pilot orifice may have
a smaller cross-sectional area than the interior of the pilot base.
In some embodiments, a pilot air passage 5 may be provided
downstream of the pilot orifice 4. The pilot air passage may permit
air to enter the pilot fuel/air passage 19. This may allow fuel and
air to mix. In some embodiments, the pilot fuel/air passage may be
a tube. The pilot fuel/air passage may have any cross-sectional
shape which may include, but is not limited to a circular shape,
elliptical shape, triangular shape, quadrilateral shape, pentagonal
shape, hexagonal shape, octagonal shape, or any other shape.
[0050] In some embodiments, a primary passage 7 may be provided,
surrounded by a secondary passage 8. In one example, the primary
and secondary passages may form concentric passages with the
primary passage in the interior and the secondary passage as the
surrounding passage, or vice versa. In some embodiments, the
primary and secondary passages may be formed as tubes (e.g.,
primary tube within the secondary tube). Alternatively, they may
have any cross-sectional shape which may include, but is not
limited to a circular shape, annular shape, elliptical shape,
triangular shape, quadrilateral shape, pentagonal shape, hexagonal
shape, octagonal shape, or any other shape. They may have the same
shape as one another or different shapes. In alternate embodiments,
the primary and secondary passages need not be within one another
and may be adjacent to one another, partially surrounded by one
another, or spaced apart from one another.
[0051] The primary passage may be slightly longer than the
secondary passage. In some embodiments, the primary passage may
extend beyond the secondary passage. The primary passage may extend
by any amount. For example, the primary passage may extend more
than, less than, or about 0.5 mm, 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6
mm, 7 mm, 8 mm, 1 cm, 1.5 cm, 2 cm, 2.5 cm, 3 cm, 4 cm, 5 cm, 10
cm, or 20 cm further than the secondary passage. The outlet of the
primary passage may be slightly higher than the outlet for the
secondary passage. The primary and secondary passages may be
oriented vertically. Alternatively, they may be oriented
horizontally or at any angle relative to vertical. The primary and
secondary passages may be oriented so that the outlet for the
primary and secondary passages is upward or at a higher elevation
than the manifold body. In alternative embodiments, the primary
passage may extend to the same amount as the secondary passage, or
the secondary passage may extend past the primary passage.
[0052] A primary fuel/air passage 7 may be in fluid communication
with the manifold body 2. In some embodiments, fuel may flow to the
primary passage via a primary orifice 12. In some embodiments, the
primary orifice may be a channel or passageway. The primary orifice
may have a smaller cross-sectional area than the interior of the
primary fuel-air passage.
[0053] In some embodiments, a primary air passage 6 may be provided
downstream of the primary orifice. The primary air passage may
permit air to enter the primary fuel/air passage. This may allow
fuel and air to mix. In some embodiments, a primary air passage may
include one air inlet, while in other embodiments, the primary air
passage may include a plurality of air inlets. In some embodiments,
a plurality of air inlets may be arranged in a radially symmetrical
fashion (e.g., two air inlets 180 degrees from one another, three
air inlets 120 degrees from one another, four air inlets 90 degrees
from one another). The air inlets may be located at or near the
bottom of the primary fuel/air passage. The primary air passage may
be located downstream of the manifold body and/or the primary
orifice. The primary air passage may be located upstream of the
primary fuel/air passage or most of the primary fuel/air passage.
In some embodiments, the primary passage outlet may be angled
upward. In some embodiments, the fuel/air mixture may travel up the
primary passage.
[0054] A secondary passage 8 may or may not be in fluid
communication with the manifold body 2. In some embodiments, the
secondary passage may be in fluid communication with the manifold
body at some times and may not be in fluid communication with the
manifold body at other times. The secondary passage may have a
default of not being in fluid communication with the manifold body
and may be brought into fluid communication with the manifold body
under certain conditions. In some alternate embodiments, the
secondary passage may have a default in being in fluid
communication with the manifold body so that a very small amount of
fluid may flow to the secondary passage, and may be brought into
greater fluid communication with the manifold body under certain
conditions. The secondary passage may be brought into or out of
fluid communication with the manifold body. The secondary passage
may be brought into or out of greater fluid flow communication with
the manifold body.
[0055] In some embodiments, fuel may flow to a secondary tube 8 via
a secondary fuel passage 21. In some embodiments, the secondary
fuel passage may be a channel or passageway. The secondary fuel
passage may have a smaller cross-sectional area than the interior
of the secondary tube. The secondary fuel passage may pass through
a manifold--burner interface 11.
[0056] In some embodiments, unlike the primary fuel/air passage 7,
no air is entrained into the secondary stream 8. No air entrainment
is needed in this embodiment because the secondary passage only
conveys substantial flow when the primary is already imparting
sufficient turbulence and pre-mixed air to the flame to prevent the
formation of smoke.
[0057] The secondary tube may include a diffuser core 10 in the
interior. In order to increase uniformity of the flame when the
secondary stream is active (for higher flow rates) the secondary
flow path may include a converging/diverging section that may form
the diffuser core. The converging/diverging section may first
accelerate the fuel by reducing cross-sectional area of the
secondary passage, and then slow the flow by gradually increasing
the cross-sectional area. This converging/diverging section may
greatly reduce the non-uniformities in fluid velocity introduced by
smaller discrete supply channels opening into a larger passage. In
some embodiments, the converging/diverging section of the diffuser
core may be formed by a shaped feature on an interior surface of
the secondary passage, an exterior surface of the primary passage,
or any combination thereof.
[0058] The secondary tube may also include a laminizer 9. In some
embodiments, the laminizer may be formed of one or more laminizer
fins. In some embodiments, the secondary flow path may include a
series of veins or fins that may divide the single large secondary
passageway into several smaller passageways or channels to reduce
the hydraulic diameter of the fluid stream, thereby reducing the
turbulence of the stream. This has the advantage of slowing the
mixing with air in the combustion region. This may result in a
taller, and therefore more visually prominent flame, which will be
further explained in greater detail below.
[0059] In some embodiments, a laminizer 9 may be provided
downstream of the diffuser core 10. In some embodiments, a
laminizer may include one laminizer fin, while in other
embodiments, the primary air passage may include a plurality of
laminizer fins. Two, three, four, five, six, seven, eight, nine,
ten, eleven, twelve, thirteen, fourteen, fifteen, sixteen or more
laminizer fins. In some embodiments, a plurality of laminizer fins
may be arranged in a radially symmetrical fashion (e.g., two fins
180 degrees from one another, three fins 120 degrees from one
another, four fins 90 degrees from one another, five fins 75
degrees from one another, six fins 60 degrees from one another, or
n fins 360/n degrees from one another). The laminizer fins may or
may not be evenly spaced from one another. The laminizer may be
located at or near the top of the secondary passage. The laminizer
may be located downstream of the manifold body, the secondary fuel
passage and/or the diffuser core. The laminizer may be located
upstream of the secondary passage outlet. In some embodiments, the
secondary passage outlet may be angled upward. In some embodiments,
the fuel may travel up the secondary passage through the diffuser
core and the laminizer Preferably, the fuel may first pass through
the diffuser core and then through the laminizer In alternate
embodiments, the fuel may pass through a laminizer before passing
through the diffuser core.
[0060] A combustion region 20 may be provided at or near the outlet
of the primary passage 7 and the secondary passage 8. The
combustion region may be provided above the outlet of the primary
and secondary passages. A flame effect may be provided by the
merging of the flames provided by the primary and secondary
passages. The flame characteristics may be determined by the
relative fuel flow to the primary and secondary passages. For
example, if more fuel flows through the primary passage, the flame
characteristics may be dominated by the primary passage. If more
fuel flow through the secondary passage, the flame characteristics
may be dominated by the secondary passage.
[0061] A flow separator may determine how fuel gets distributed
from the manifold body 2 to the primary passage 7 and/or the
secondary passage 8. In some embodiments, the flow separator may be
implemented as a spring-loaded relief valve. This may include a
movable relief plunger 15 that may form a seal, or a near seal,
against a stationary valve seat 18. In some embodiments, a relief
O-ring 17 may assist with forming the seal or near seal against the
valve seat. A relief spring 14 may push the plunger 15 against the
valve seat 18 to maintain the seal. In other embodiments, other
mechanisms, such as elastics, deforming pieces, flexible pieces, or
tension mechanisms may be used, and any description of a spring may
also apply to such mechanisms. The spring or other mechanism may
rest on a relief plug 13. The primary fuel/air passage 7 is
connected directly to the burner's fuel supply, upstream of the
relief valve. The secondary passage 8 lies downstream of the relief
valve, and is therefore substantially blocked from receiving fuel
by the plunger 15 sealing against the seat 18.
[0062] In a preferable embodiment, a small bypass hole 16 through
the plunger may allow a small amount of fuel through to the
secondary passage 8 while the relief is closed. Having some fuel
flow in the secondary passageway, even for low fuel flow rates, may
be beneficial by allowing some resistance to wind because of the
fuel eddy behind a protruding primary tube. In other embodiments, a
bypass hole is not provided and when the relief is closed fuel does
not flow to the secondary passage.
[0063] The flow separator may divert substantially all of the fuel
to the primary flow path until the fuel throughput reaches a high
enough rate that the pressure presented at the surface of the
relief plunger 15 is sufficient to overcome the force of the spring
14 or other mechanism holding the plunger against the valve seat
18. Once the fuel throughput reaches the rate required to lift the
relief plunger 15, most additional fuel flow may be diverted to the
secondary flow path 8. This may be a threshold condition that may
permit an increasing amount of fuel to flow to the secondary flow
path. The flow separator may be a pressure-driven flow separator
where an increased amount of fuel is permitted to flow to the
secondary flow path as the amount of total fuel to the manifold is
increased past a threshold. The ratio of fuel provided to the
secondary flow path relative to the primary flow path may increase
as the total fuel to the manifold is increased. In some instances,
a total fuel flow rate may reach a point where the flow separator
reaches a maximum open position, after which the ratio of fuel
provided to the secondary flow path relative to the primary flow
path may stabilize.
[0064] At low flow rates in quiescent air, there may be little or
no turbulence in the flame, meaning smoke is more likely to be
observed. To eliminate visible smoke at low flow rates, the primary
flow path may include an inspirator with a primary air passage 6,
which entrains some air into the fuel stream through several air
inlets. After the inspirator, a length of channel 7 may be provided
to allow the air to mix with the fuel before the primary outlet
into the combustion region 20.
[0065] The cross-sectional area of the primary flow path 7 may be
small in order to sustain a greater fluid velocity at lower flow
rates. In some embodiments, the cross-sectional area may be about
0.1'', 0.2'', 0.25'', 0.3'', 0.4'', 0.5'', 0.7'', or 1.0''. The
greater exit velocity may allow the primary flow path to support a
more stable flame at its outlet for very low flow rates, and may
also impart momentum to the secondary stream at greater flow
rates.
[0066] For high total fuel flow rates, most of the fuel may be
directed to the secondary flow path 8. Therefore, the secondary
fuel stream may dominate the characteristics of the flame for
larger flames. To maintain a fully-attached flame at higher flow
rates, the secondary flow path may have a much larger
cross-sectional area at its outlet than the primary flow path 7. In
some embodiments, the cross-sectional area of the secondary flow
path may be about 0.5'', 0.75'', 1'', 1.25'', 1.5'', 2'', 3'', or
5''. In some embodiments, the ratio of cross-sectional area for the
secondary flow path to the cross-sectional area for the primary
flow path may be greater than, less than, or equal to about 1:1,
2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 12:1, 15:1, 20:1,
30:1, or 50:1. This larger area may result in a lower fuel-exit
velocity. The velocity of the fuel exiting the burner may
preferably be below the flame speed at the burner exit for the
flame to remain attached.
[0067] FIG. 4 is an additional cross-sectional view of a
multi-stage burner. The multi-stage burner may have a pilot 400,
primary flow path 402, and secondary flow path 404. As previously
discussed, fuel may be provided from a fuel supply and the total
fuel flow rate may be controlled by a proportional valve.
[0068] A multi-stage burner may have a proportional valve outlet
406 that may accept the fuel supplied and controlled by the
proportional valve. The proportional valve outlet may direct the
fuel into a manifold 408. Fuel may flow from the manifold through a
pilot noise reduction orifice 410 to a pilot flow path. The fuel
may flow through a pilot fuel orifice 412 within the pilot and may
encounter one or more pilot air passages 414. The pilot air
passages may allow air to enter the pilot and mix with the fuel.
The fuel-air mixture may travel up the pilot 400.
[0069] Fuel may also flow from the manifold 408 through a primary
fuel orifice 416 into a primary flow path 402. The fuel may
encounter one or more primary air passages 418. The primary air
passages may allow air to enter the primary flow path and mix with
the fuel. The fuel-air mixture may travel up the primary flow
path.
[0070] Fuel may also flow through the manifold 408 and encounter a
relief valve. At a default position, a relief needle 420 may block
the fuel from flowing to the secondary flow path 404. A relief
spring 422 may bias the relief needle against a seat. When
sufficient fuel throughput is provided, the pressure from the fuel
may be sufficient to overcome the spring and may cause the relief
needle to retract. When the relief needle retracts, fluid
connection to the secondary flow path may be provided. As the
relief needle retracts further, an increased fluid connection to
the secondary flow path may be provided. A flow passageway in fluid
communication with a secondary fuel passage 424 may be provided in
accordance with any embodiment of the invention. The secondary fuel
passage may have a smaller cross-sectional area than the overall
secondary flow path. In some embodiments, one, two, or more
secondary fuel passages may be provided to convey fuel to the
secondary flow path. The secondary flow path may include a diffuser
core 426 and one, two, or more laminizer fins 428. In some
embodiments, the fuel may first encounter the diffuser core, and
may then pass between the laminizer fins. The fuel may travel up
the secondary flow path.
[0071] In some embodiments, one or more O-rings or other similar
features may be used to assist with sealing various parts of the
multi-stage burner. For example, a relief O-ring may be provided at
the relief needle, to assist with sealing the relief needle against
the valve seat. In another example, an O-ring may be provided at
the manifold-burner interface. This may assist with keeping the
manifold-burner interface sealed as fuel may flow from the manifold
to the flow paths.
[0072] In some embodiments, an electrically insulating disk 430 may
be provided between the manifold-burner interface and the manifold
408. The insulating disk may electrically insulate the burner from
the manifold.
[0073] In some embodiments, the multi-stage burner may be arranged
with the primary flow path running up the center of the secondary
flow path. The primary flow path may be provided within a primary
tube, and a secondary flow path may be provided within a secondary
tube. The primary tube may terminate about 1/8'' (or any other
distance mentioned elsewhere herein) above the termination of the
secondary tube so that the smaller primary tube extends slightly
past the secondary tube.
[0074] This configuration may be advantageous for a number of
reasons. First, the primary and secondary fuel streams may be
uniformly combined with respect to the axis of both streams,
creating a flame that looks uniform from all viewing angles in
still air. For example, both the primary and secondary fuel streams
may have the same axis. The axis may be located at or near the
center of the tubes. In some embodiments, the axis may be a
vertical axis. Alternatively, the axis may be a horizontal or
angled axis. Co-axial primary and secondary fuel streams may permit
the fuel streams to be visually combined.
[0075] Second, for higher flow rates when the secondary fuel stream
is flowing a substantial amount of gas, the slower, laminar
secondary flow may shield the faster, more turbulent primary flow
from air for a substantial distance above the burner outlet. This
may slow the mixing of the fuel with air by reducing the turbulence
at the fuel-air interface, which may provide a taller flame than
would be realized otherwise.
[0076] Third, for low and intermediate flows, the secondary fuel
stream may release a small amount of slowly-flowing gas in an even
pattern around the primary outlet. In wind, this slow-moving gas
may be pushed away from the upwind side of the secondary outlet,
and towards the downwind side, which is partially shielded by the
protruding primary tube. This collection of secondary fuel in the
lee of the primary may help the burner maintain a flame in higher
winds than would be realized in other arrangements.
[0077] FIG. 5 provides an exploded view of a multi-stage burner
provided in accordance with an embodiment of the invention. The
multi-stage burner may have a first fuel passage passing through a
burner inner tube 500 and a second fuel passage passing through a
burner outer tube 502. In one example, the first fuel passage may
have a circular cross-section while the second fuel passage may
have an annular cross-section.
[0078] A proportional valve 504 may deliver fuel to a manifold 506
of the burner. A pilot base 508 may be connected to the manifold.
In some instances, the pilot base may screw into the manifold. The
pilot base may be welded, locked, clamped, adhered, or attached to
the manifold in any other manner known in the art. A pilot tube 510
may be connected to a pilot base. In some embodiments, a pilot tube
may slide over a portion of the pilot base. The pilot tube may be a
separate or separable piece from the pilot base. Alternatively, the
pilot tube may optionally be integrally formed of a single piece
with the pilot base.
[0079] In some embodiments, a third fuel passage in the pilot may
be provided to aid the ignition of the flame. Fuel may be supplied
to this passage from the manifold 506. Fuel may be supplied to the
pilot from the same manifold as the inner burner. A very small
channel in the manifold may convey fuel to a chamber between the
threaded pilot base 508 and the manifold. This small channel may
serve to slow the flow of fuel to the pilot, thereby reducing the
noise that the pilot produces. Next, the pilot fuel may flow
through a pilot orifice in the pilot base. Air may be introduced to
the pilot stream just past the orifice, and the mixture may flow up
the pilot tube to where it exits near the main burner exit. An
inspirator for the pilot may be constructed to produce a mixture
that has a much lower fuel-air ratio than the primary stream, and
which is nearly stoichiometric. This mixture ratio may be
beneficial in that it may be easily ignited by an electric
spark.
[0080] A burner base 512 may be connected to the manifold 506. In
some embodiments, an insulating disk 514 may be provided between
the burner base and the manifold. The insulating disk may
electrically insulate the burner from the manifold.
[0081] The burner base 512 may also have several machined features
that may assist with the operation of the burner. A small hole in
the center may serve as an orifice for an inspirator that may draw
air into a primary stream. Air passages 516 may convey air to the
primary stream just downstream of the orifice, thus forming the
inspirator, which may reduce smoke production. In some instances,
any number of radial air passages may be provide (e.g., 1, 2, 3, 4,
5, 6 or more). Secondary fuel passages may be drilled axially in
locations that alternate with the aforementioned air passages. For
example, if three air passages are provided, three secondary fuel
passages may be provided. These fuel passages may transmit fuel
from an annular region between the manifold 506 and the burner
base, through the burner base, to the annular region between the
burner inner 500 and outer 502 tubes.
[0082] One, two or more circumferential grooves in the burner
interface may retain o-rings. In one embodiment, the smaller of two
o-rings may separate primary and secondary flow paths. The larger
of the two o-rings may separate the secondary flow path from the
atmosphere at the burner-manifold interface. These two o-rings and
the insulating disk that rests between the burner base and the
manifold may serve to electrically insulate the burner assembly
from the manifold, while maintaining a positive fluidic seal. This
may permit the burner assembly to be used as a flame detection
sense terminal.
[0083] A burner inner tube 500 may be connected to the burner base
512. In some embodiments, the burner inner tube may fit into a
lower inner part of the burner base. In some embodiments, the
interior of the inner tube may be in fluid communication with a
central portion of the burner base without being in fluid
communication with a peripheral portion of the burner base. In some
embodiments, the interior of an inner tube may retain a uniform
cross-section. For example, the interior of the inner tube may be
straight. In other embodiments, the interior of the inner tube may
vary along the length of the tube.
[0084] The inner tube may also include a diffuser core 518 and one
or more laminizer fins 520. The diffuser curve may be formed on an
outer surface of the inner tube. The diffuser core may bulge
outward from the outer surface of the inner tube. In some
embodiments, the diffuser core may be a separate piece that fits
over the inner tube. Alternatively, the diffuser core may be
integrally formed of a single piece from the inner tube. The
interior of the diffuser core may be solid or hollow. The laminizer
fins may protrude from the surface of the inner tube. The laminizer
fins may have a parallel orientation with respect to an axis of the
inner tube. For example, if an inner tube is oriented vertically
the laminizer fins may also be oriented vertically. The laminizer
fins may extend outward in a radial fashion from the inner tube.
The laminizer fins may be separate or separable pieces attached to
the inner tube, or may be integrally formed on the inner tube.
[0085] A burner outer tube 502 may fit over a burner inner tube
500. The burner outer tube may cover a diffuser core 518 and/or
laminizer fins 520 of the burner inner tube. The burner outer tube
may contact or connect to the burner base 512. In some instances,
the burner outer tube may fit over a portion of the burner base.
The interior of the burner outer tube may be in fluid communication
with a peripheral portion of the burner base without being in fluid
communication with a central portion of the burner base. When
assembled, in some embodiments, the burner inner tube may extend
past the burner outer tube.
[0086] The construction of a burner may comprise a burner base, the
burner outer tube that conveys the secondary flow to the burner
outlet, the burner inner tube that conveys the primary flow to the
burner outlet, a diffuser core encircling the burner inner tube and
laminizer fins attached to the burner inner tube. The burner inner
and burner outer tubes may be co-axial so that the primary stream
(e.g., inner stream) flows up the center of the secondary stream
(e.g., outer stream). The burner base may provide the structural
support for both tubes at their bases.
[0087] A relief needle 522, relief spring 524, and relief plug 526
may be connected to the manifold. The relief needle may retract
when a sufficient pressure is exerted on the relief needle. When
the relief needle is in an unretracted or closed state, fluid
communication may be provided between the manifold 506 and the
burner inner tube 500 without fluid communication or with extremely
little fluid communication being provided between the manifold and
the burner outer tube 502. When the relief needle is in a retracted
or open state, the fluid communication may be provided between the
manifold and the burner inner tube with fluid communication or with
an increased amount of fluid communication being provided between
the manifold and the burner outer tube. The relief needle may have
a varying range of retraction in the open state. The relief needle
degree of openness may be continuously variable.
[0088] The relief needle may be capable of being retracted or
unretracted at a rapid rate. The flame characteristics may be able
to rapidly vary corresponding to the rapid variation in
distribution of fuel to one or more different output flow paths
based on the relief valve. The flame characteristics may be able to
vary widely in a short amount of time.
[0089] An inline filter 528 may be provided. The inline filter may
connect to the manifold 506. In some embodiments, the inline filter
may screw into the manifold. The inline filter is useful for
reducing debris that may stop the valve or flame effect from
operating properly.
[0090] A reducing coupler 530 may be connected to the inline filter
528. In some embodiments, the reducing coupler may screw into the
inline filter. The reducing coupler may adapt the plumbing to the
correct size.
[0091] A quick connect filter 532 may be connected to the reducing
coupler 530. The quick connect filter may screw into the reducing
coupler. The quick connect filter may allow for easy connection and
disconnection of the fuel supply.
[0092] FIG. 6 shows an example of a flame element provided in
accordance with an embodiment of the invention. A flame element may
include a multi-stage burner that may be in communication with a
fuel inlet 600. The multi-stage burner may include a manifold 602,
a main burner 604, a pilot 606 and an ignitor 608. The multi-stage
burner may have one or more of the characteristics described
elsewhere herein. A gas inlet may provide fuel to the manifold of
the burner. The manifold may distribute fuel to the pilot and the
main burner.
[0093] A valve 610 may be connected to the manifold 602. The valve
may be useful for controlling the flow of fuel into the manifold.
The valve may be a proportional solenoid valve, a pilot operated
valve, a servo-actuated valve, a muscle wire actuated valve, or any
type of valve that permits variable control of fuel flow to the
manifold.
[0094] A circuit board 612 (e.g., printed circuit board--PCB) may
be provided. The circuit board may be connected to one or more
electrical connectors 614. The electrical connectors may provide
power to the circuit board. Alternatively, the flame element may
have an internal power source. The circuit board may include
processors, tangible computer readable media, logic, code,
instructions, or memory that may assist with controlling the
burner. The circuit board may provide one or more signals to an
igniter which may ignite a flame. The circuit board may provide one
or more signals to the valve, which may control the flow of fuel
from the gas inlet to the manifold 602. The valve may control the
flow rate of fuel from the gas inlet to the manifold. In some
embodiments, the flow rate of the fuel may be varied at a rapid
rate. For example, the flow rate may be varied up to about 1000
times per second (1 KHz), 2000 times per second (2 KHz), 3000 times
per second (3 KHz), 4000 times per second (4 KHz).
[0095] The flame element may be enclosed or partially enclosed
within a housing 616. The housing may surround the circuit board
612, valve 610, and a portion of the gas inlet 600. The housing may
enclose a portion of the manifold 602. The burner 604 may extend
from the housing. In some instances, the burner may extend from the
top of the housing.
[0096] The housing 616 may include a bottom cap 618. In some
instances, the bottom cap may be screwed into the housing, or
attached in any other way know in the art. The bottom cap may
include one or more openings that may permit a gas inlet and/or
electrical connections to pass to the exterior of the housing.
Alternatively, a local fuel source and/or power source may be
provided within the housing of the flame element, so openings may
not be required.
[0097] It should be understood from the foregoing that, while
particular implementations have been illustrated and described,
various modifications can be made thereto and are contemplated
herein. It is also not intended that the invention be limited by
the specific examples provided within the specification. While the
invention has been described with reference to the aforementioned
specification, the descriptions and illustrations of the preferable
embodiments herein are not meant to be construed in a limiting
sense. Furthermore, it shall be understood that all aspects of the
invention are not limited to the specific depictions,
configurations or relative proportions set forth herein which
depend upon a variety of conditions and variables. Various
modifications in form and detail of the embodiments of the
invention will be apparent to a person skilled in the art. It is
therefore contemplated that the invention shall also cover any such
modifications, variations and equivalents.
* * * * *