U.S. patent application number 14/421122 was filed with the patent office on 2015-10-01 for low cost radial gas-burner.
The applicant listed for this patent is Daniel Mark St. Louis. Invention is credited to Daniel Mark St. Louis.
Application Number | 20150276218 14/421122 |
Document ID | / |
Family ID | 50101580 |
Filed Date | 2015-10-01 |
United States Patent
Application |
20150276218 |
Kind Code |
A1 |
St. Louis; Daniel Mark |
October 1, 2015 |
Low Cost Radial Gas-Burner
Abstract
A Low Cost Radial Gas Burner (LCRGB) burner comprises a gas
turbulator means, at least one means for producing an
ambient-air-inducing jet of the gaseous fuel to create a
self-sustaining combustible fuel-air mixture, and a combustion
initiation means located at a combustion initiation position
proximate the gas turbulator means. The gas turbulator means has a
planar surface. The jet of gaseous fuel is directed towards the
planar surface to envelope the gas turbulator means and is ignited
by the combustion initiation means. The gas turbulator means may be
configured as a planar rotor having a flow deflector and turbine
vanes. In yet another embodiment of the LCRGB, there are at least
two jets of the gaseous fuel which are directed to the planar
surface of the gas turbulator means.
Inventors: |
St. Louis; Daniel Mark;
(Wichita, KS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
St. Louis; Daniel Mark |
Wichita |
KS |
US |
|
|
Family ID: |
50101580 |
Appl. No.: |
14/421122 |
Filed: |
August 10, 2013 |
PCT Filed: |
August 10, 2013 |
PCT NO: |
PCT/US13/54442 |
371 Date: |
February 11, 2015 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
61682573 |
Aug 13, 2012 |
|
|
|
Current U.S.
Class: |
431/355 |
Current CPC
Class: |
F23D 2900/14021
20130101; F23D 14/70 20130101; F23D 14/62 20130101; F23D 14/06
20130101; F23D 14/02 20130101 |
International
Class: |
F23D 14/06 20060101
F23D014/06; F23D 14/62 20060101 F23D014/62 |
Claims
1. A burner for combusting a gaseous fuel, the burner comprising: a
gas turbulator means; at least one means for producing an
ambient-air-inducing jet of the gaseous fuel to create a
combustible fuel-air mixture, the jet being directed towards and
enveloping the gas turbulator means; and a combustion initiation
means located at a combustion initiation position proximate the gas
turbulator means to initiate the combustion of the fuel-air mixture
around the gas turbulator means.
2. The burner of claim 1 wherein the gas turbulator means has a
planar surface and the jet of the gaseous fuel is directed at the
planar surface.
3. The burner of claim 1 wherein the gas turbulator means is
configured as a planar rotor.
4. The burner of claim 3 wherein the the planar rotor has a flow
deflector and turbine vanes.
5. The burner of claim 4 wherein the flow of the air-fuel mixture
past the turbine vanes causes the rotor to spin and further mix the
air and fuel in the air-fuel mixture.
6. The burner of claim 4 wherein a spin inducing means is coupled
to the rotor to cause the rotor to spin and further mix the air and
fuel in the air-fuel mixture.
7. The burner of claim 6 wherein the spin inducing means is an
electric motor.
8. The burner of claim 6 wherein the spin inducing means is a
fluidic motor.
9. The burner of claim 2 wherein there are at least two jets of the
gaseous fuel which are directed to the planar surface of the gas
turbulator means.
Description
RELATED APPLICATIONS
[0001] This application claims priority from U.S. Provisional
Patent Application No. 61/682,573 filed on Aug. 13, 2012.
FIELD OF THE INVENTION
[0002] The present invention relates to low-heat capacity gas
burners for use in domestic, industrial, and commercial
applications.
BACKGROUND
[0003] Most low-heat capacity burners (having heat-output in the
range of 500 to 400,000_BTUH) are the Venturi Driven and Fan
Assisted Premix Burner (referred to herein as "Premix" Burner)
type. Premix burners typically have a venturi as part of the burner
design. The purpose of the venturi is to provide good mixing of the
correct proportions of fuel and air, and to use the momentum of the
gaseous fuel to direct the flame as required. Premix burners are
commonly used in propane torches, home furnaces, home hot water
heaters, gas stoves, and other domestic and commercial appliances.
The premix burner that is used in domestic tank-type water heaters
is a special case of a premix burner in that the jet of gas
impinges on a lower plate that redirects the flow of gaseous fuel
radially after which the flow enters a radial design venturi. The
air and fuel emerge from the venturi to combust and create a radial
flame pattern. Because of its size and shape, the home hot water
heater burner is commonly known in the industry as a "pancake
burner".
[0004] Pancake burners are relatively inexpensive to produce, but
in the highly competitive market of domestic hot water heaters any
significant cost savings to the burner would be of great
importance, especially considering that many millions of hot water
heaters which use pancake burners are sold every year.
[0005] A recent development in domestic water heaters is the
tankless water. This uses a premix burner which is configured to
produce a line of flame jets. The flame jets heat the water which
flows in a finned heat exchanger to rapidly heat the water as
demanded. These premix burners, referred to herein as "sandwich"
burners, are produced by peripherally unitizing two stamped plates.
The sandwich burners therefore are more complicated to design and
manufacture than the pancake burners described above.
[0006] The pancake and sandwich burners are typically formed by
blanking, stamping and punching relatively large steel plates. The
stamping dies are very expensive and the stamping operations
require very capital intensive specialized equipment. The complex
stampings are necessary so that when two plates are assembled
together, they form the necessary radial or linear venturi.
[0007] Another application of the Low Cost Radial Gas Burner is as
an economical replacement for linear burners such as those found in
most home furnaces and in most torches. These linear burners
produce a very long and narrow flame. In some applications, a long
narrow flame is not economical or practical and a pancake burner is
not practical either as it will not provide the correct flame
coverage. An array of Low Cost Radial Gas Burners is contemplated
to be an economical substitution for linear burners in such
applications.
[0008] Thus, what is needed is a simple and economical gaseous fuel
burner that can be manufactured at a lower cost and can also
provide better flame coverage than pancake and sandwich
burners.
SUMMARY
[0009] A Low Cost Radial Gas Burner (LCRGB) burner for combusting a
gaseous fuel is disclosed. The burner comprises a gas turbulator
means, at least one means for producing an ambient-air-inducing jet
of the gaseous fuel to create a combustible fuel-air mixture and a
combustion initiation means located at a combustion initiation
position proximate the gas turbulator means. The jet of gaseous
fuel is directed towards and envelopes the gas turbulator means and
is ignited by the combustion initiation means. The gas turbulator
means has a planar surface and the jet of the gaseous fuel is
directed at the planar surface.
[0010] In one embodiment of the LCRGB, the gas turbulator means is
configured as a planar rotor having flow deflector and turbine
vanes. The flow of the air-fuel mixture past the turbine vanes
causes the rotor to spin and further mix the air and fuel in the
air-fuel mixture.
[0011] In another embodiment of the LCRGB, a spin inducing means
such as an electric or a fluidic motor is coupled to the rotor to
spin the rotor and further mix the air and fuel in the air-fuel
mixture.
[0012] In yet another embodiment of the LCRGB, there are at least
two jets of the gaseous fuel which are directed to the planar
surface of the gas turbulator means.
[0013] In yet another embodiment of the LCRGB, the jet of gaseous
fuel is directed to an upper surface of the turbulator.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1A is an isometric representation of a first embodiment
of the Low Cost Radial Gas Burner 10 described herein.
[0015] FIG. 1B is an elevation view cross-sectional representation
of the Low Cost Radial Gas Burner 10 described herein in operation.
The burner element 10 is being supplied with a gaseous fuel through
a gas supply pipe. The flames propagate radially across turbulator
disk 10d.
[0016] FIG. 1C is an elevation view cross-sectional representation
of the Low Cost Radial Gas Burner 10 described herein showing the
major components of the burner.
[0017] FIG. 1D is an elevation view cross-sectional representation
of the Low Cost Radial Gas Burner 10 described herein wherein disk
10d is supported independently of the gaseous fuel ejector 10n.
[0018] FIG. 2 is a plan view cross-sectional representation of the
Low Cost Radial Gas Burner 10 of FIG. 1C.
[0019] FIG. 3 is another plan view cross-sectional representation
of the Low Cost Radial Gas Burner 10 of FIG. 1C.
[0020] FIG. 4 is an elevation view cross-sectional representation
of a second embodiment of the Low Cost Radial Gas Burner 10
described herein wherein the gas ejector is located at an elevated
position relative to the gas supply pipe.
[0021] FIG. 5 is an elevation view cross-sectional representation
of a third embodiment of the Low Cost Radial Gas Burner 10
described herein wherein an air eductor is provided around the gas
ejector to control the amount of ambient air that can be induced
into the gaseous fuel jet stream.
[0022] FIG. 6 is a plan view cross-sectional representation of the
Low Cost Radial Gas Burner 10 of FIG. 5.
[0023] FIG. 7 is an isometric representation of a fourth embodiment
of the Low Cost Radial Gas Burner described herein.
[0024] FIG. 8A is another isometric representation of the
turbulator disk of FIG. 7.
[0025] FIG. 8B is a plan view cross-sectional representation of the
turbulator disk of FIG. 7.
[0026] FIG. 9A is a elevation view cross-sectional representation
of the sandwich burner according to the prior art.
[0027] FIG. 9B is an elevation view cross-sectional representation
of a row of LCRGBs 10 that can be substituted for the sandwich
burner of FIG. 9A.
[0028] FIG. 10A is an isometric representation of another
embodiment of the LCRGB wherein the jet of gaseous fuel is directed
to an upper surface of the turbulator disk.
[0029] FIG. 10B is an elevation view cross-sectional representation
of the LCRGB of FIG. 10A.
[0030] FIG. 10C is an elevation view cross-sectional representation
of the LCRGB of FIG. 10A which uses a deflector disk to direct the
gaseous fuel to the upper surface of the turbulator disk.
DESCRIPTION OF THE INVENTION
[0031] This application discloses a low cost radial gas burner
element which is simple in construction and relatively inexpensive
to mass-produce. This burner element can be used in residential
appliances such as cooking ranges, hot water heaters, home
furnaces, home tankless or tank type hot water heaters, gas stoves,
and other domestic appliances. The burner element also finds
applications in commercial and industrial appliances such as
central heating furnaces, hot water heaters or boilers, industrial
dryers, and other equipment. The Low Cost Radial Gas Burner element
described herein (which will be commercially marketed as a "micro
disk burner") is a very simple and economical alternative to
conventional pancake and sandwich burners.
[0032] The Low Cost Radial Gas Burner simply consists of a gas jet
that impinges on a small disk or plate. It was discovered through
experimentation that this very simple arrangement creates a very
good burner that is clean burning and has a very desirable flame
shape and very optimal flame coverage for some applications. The
design of the burner is based on scientific principles used in HVAC
engineering and air handling equipment design. These principles
state that changes of direction of airflow produce turbulence and
mixing. These principles have been applied to the LCRGB described
herein and the result is that the need for a venturi in order to
provide a good burner flame has been eliminated.
[0033] In operation, the gas jet impinges on a turbulator on which
the gas jet is redirected along the surface of the turbulator. The
turbulator can be in the form of a disk or a square plate or
rectangular plate or a ribbon or any other shape which has a planar
surface. When the gas jet is redirected on the planar surface of
the turbulator, the turbulence from the change of direction helps
entrain and mix ambient air into the stream of gaseous fuel. Thus,
enough air is entrained into the gas jet in a very short distance
along the planar surface to provide a self-sustaining combustible
fuel-air mixture. Still further mixing is attained as the fuel and
air exit the circumference of the micro-disk. Fluid dynamics forces
try to keep the flow attached to the disk. However, the sharp
discontinuity at the edge of the disk makes this impossible. The
result is a zone of toroidal flow all around the circumference of
the disk. This toroidal flow produces intense mixing and also
creates a mechanism for producing a stable flame. The proportion of
air and gaseous fuel in the resulting air-fuel mixture is
sufficient to support sustained combustion. The air and gaseous
fuel are thoroughly mixed and the mixture produces a very good
flame and efficient combustion.
[0034] FIGS. 1A, 1B, 1C, 2, and 3 are various representations of
the Low Cost Radial Gas Burner 10 described herein. Low Cost Radial
Gas Burner 10 comprises a floor member 10f which supports a fuel
gas supply pipe 10p. Pipe 10p is connected to a fuel ejector or
nipple 10n which has an outlet orifice 10no through which the
gaseous fuel exits as a jet stream into the ambient air. Low Cost
Radial Gas Burner 10 further comprises a turbulator which is
configured as disk 10d on which the gas jet impinges during
operation. Disk 10d is supported at a required distance from the
nipple orifice 10no by supports 10s which are connected to floor
member 10f. Turbulator disk 10d can be made of a suitable metal or
a suitable ceramic or any other high-temperature resistant
material. Supports 10s can be thin steel rods which are rigid
enough to support the weight of disk 10d. Supports 10s can be
attached to floor member 10f and disk 10d by welding or mechanical
attachments such as hooks or any other means that will be obvious
to persons having ordinary skill in the mechanical arts.
[0035] As shown in FIG. 1B, a gaseous fuel at a relatively higher
pressure than ambient is supplied to burner pipe 10p. The gaseous
fuel exits as a high-velocity jet through nipple orifice 10no. A
simple hole drilled in a pipe or tube may be sufficient to function
as nipple orifice 10no. As the gaseous fuel moves through the
ambient air, it induces ambient air into the jet stream to form a
self-sustaining combustible gaseous fuel-air mixture. The gaseous
fuel-air mixture impinges upon the lower face 10df of disc 10d
resulting in localized turbulence which further mixes the gaseous
fuel with the entrained and surrounding ambient air. The turbulent
fuel-air mixture is capable of sustaining combustion and can be
ignited by a combustion initiation means (CIM) 10z. CIM 10z could
be any means of igniting a flame such as a standard spark igniter
or a pilot flame or a glowbar or a burning matchstick or even a hot
ember.
[0036] As mentioned previously, the flame produced by this simple,
inexpensive burner is comparable to the flame produced by the more
complicated and expensive pancake burner. The Low Cost Radial Gas
Burner provides flame coverage that is comparable to the flame
produced by the pancake burner. Further, CO and NOx levels of the
Low Cost Radial Gas Burner are comparable to those of the pancake
burner. Cost-wise, it is estimated that the Low Cost Radial Gas
Burner could be produced at a fraction of the cost of the pancake
burner.
[0037] FIG. 4 is a vertical cross-sectional representation of the
Low Cost Radial Gas Burner 10 wherein the gas ejector 10n is
elevated from the floor member 10f. This embodiment can be used
wherein it is desirable to have the flame in a somewhat remote
location. The constructional and operational details of the second
embodiment of Low Cost Radial Gas Burner 10 are similar to those of
the first embodiment of the Low Cost Radial Gas Burner shown in
FIG. 1C.
[0038] FIGS. 5 and 6 show vertical and plan view cross-sectional
representations of a third embodiment of the Low Cost Radial Gas
Burner 10 wherein an eductor 10e is located around gas ejector 10n.
Eductor 10e has air supply orifices 10eo through which air is
induced into the gaseous fuel jet stream. By controlling the size
of orifices 10eo, the amount of air that is induced into the
gaseous fuel jet stream can be controlled. This embodiment can be
used in applications which require a finer control of the air-fuel
ratio used in the burner. The constructional and operational
details of the third embodiment of Low Cost Radial Gas Burner 10
are similar to those of the first embodiment of the Low Cost Radial
Gas Burner shown in FIG. 1C except that air is drawn into the
gaseous fuel jet stream through eductor orifices 10eo.
[0039] From the above description it is quite obvious that the
micro disk burner is a very simple design that uses a fraction of
the material and manufacturing costs compared to a pancake burner.
The micro disk burner can be produced economically by most sheet
metal shops with very standard and simple tooling. The savings in
material and in forming result in a burner that is substantially
less expensive than a standard pancake burner which is currently
used in most appliances.
[0040] It will be quite obvious that there is no true limit to how
small or large turbulator disk 10d can be to operate properly. The
applicant has successfully operated micro-disk burners which have
turbulator disks which were half-inch in diameter to many inches in
diameter. These dimensional ranges are not limiting and smaller or
larger simple micro disk burners may have applications.
[0041] A one and one half-inch disk was tested as a direct
replacement for a pancake burner in a conventional domestic hot
water heater. The results were that the micro disk equaled or
outperformed the pancake disk in all regards at a fraction of the
cost. When fired in open air, the flame diameter of the micro disk
is smaller than that of the pancake burner. However, in the air
flow environment created by the combustion chamber of the
conventional domestic hot water heater, the micro disk burner
produces a nearly identical sized and shaped flame as the pancake
burner. Thus the micro disk burner produces the same heating
characteristics as a pancake burner but at a lower cost.
[0042] It will be quite obvious that the micro disk burner is not
limited to operation with natural gas but it can be designed to
operate with any common gaseous fuel such as butane or propane.
[0043] It will be quite obvious also that the micro disk burner
design is not limited to turbulators which are configured as round
cross section disks. Other shapes such as a square plate or a star
or a toothed wheel cross-sectioned plate can be used for the
turbulator. As another example, a disk with holes proximate to its
periphery could be used as the turbulator. These modifications to
the disk would further enhance flame turbulence resulting in more
complete combustion. Further, these shapes may be useful in further
enhancing or modifying the shape of the flame.
[0044] The micro disk burner can create a short and relatively
constant flame front. This "wall of fire" is ideal for heating a
surface such as a pot or pan when used to replace the common gas
burner on a domestic or commercial stove. Further, by heating from
the center of the pot or pan, more heat transfer can be expected to
the cooking utensil resulting in greater energy efficiency.
[0045] Operating several micro disk burners in an array can further
expand the "wall of fire" concept. This larger wall of fire would
be well suited for evenly heating a larger object such as a heat
exchanger. One practical example would be to provide heat to the
heat exchanger in a gas fired tankless water heater. Currently
these water heaters use a very large array of linear venturi
burners. These linear venturi burners create a long narrow flame
and have the following disadvantage in this application: (a) The
heating is not inherently even, (b) a very large number of
individual burners/flames are required in an attempt to achieve
more even heating of the heat exchanger, (c) the large number of
individual burners is costly, and (d) the long flames necessitates
a tall combustion chamber which increases cost and restricts the
installation space for the heater.
[0046] Alternately, the tankless water heater may use a sandwich
burner. The general representation of a sandwich burner used in
some conventional water heaters is shown in FIG. 9A. As shown in
FIG. 9A, sandwich burners of the prior art are fabricated by
peripherally unitizing two plates which were previously stamped to
create the complex venturi flow channels there between. It will be
obvious from FIG. 9A, that the manufacturing processes to create
these plates and unitize them to form the sandwich burner are
complicated and expensive. The sandwich burner can be economically
replaced by a row of LCRGBs 10, as shown in FIG. 9B, resulting in a
lower cost tankless water heater.
[0047] To further reduce costs, as shown in FIG. 9B, the individual
turbulator disks may be aggregated as a single strip on which
multiple gaseous fuel jets impinge. Thus a long strip of flame
(instead of multiple individual flames) will be produced which will
provide more efficient heat transfer in a smaller space. The single
strip can be a plain rectangular strip or a toothed rectangular
strip or any other complex shape which may be useful in further
enhancing or modifying the shape of the flame.
[0048] Still further modifications such as bumps, bent edges,
waves, perturbations, holes, curvatures, geometric, and
non-geometric cross sections may be provided on the turbulator disk
or strip for specific burner applications. These changes and others
may be implemented without departing from the spirit of this
invention.
[0049] It will be obvious to one of ordinary skill in the art that
there are countless variations which may possibly be used for
producing the Low Cost Radial Gas Burner described herein.
[0050] For example, the gaseous fuel ejector 10n and turbulator
disk 10d do not need to be an integral unit to form the Low Cost
Radial Gas Burner. As shown in FIG. 1D, they may be supported
separately while maintaining the relative location of the gaseous
fuel jet ejector 10n and disk 10d. Thus ejector 10n and disk 10d
cooperate to function as the burner. For example, the disk 10d
could be installed inside a domestic water heater supported from
the central baffle plate or other convenient structure, separately
from ejector 10n. But they would work together to function as a Low
Cost Radial Gas Burner.
[0051] Yet further as shown in FIGS. 7, 8A, and 8B with respect to
the fourth embodiment of Low Cost Radial Gas Burner 20, turbulator
disk 20d may be integrated into a mechanical mixer. Such an
arrangement was tested and found to provide very thorough mixing in
a very small space. Disk 20d is configured as a rotor with flow
deflector 20dz and turbine vanes 20dv which spins around center
20dc. Disk 20d can be self-spinning being motivated by the flow of
the air-fuel mixture past vanes 20dv. Alternately, it can be spun
by an external rotating device such as an electric or fluidic motor
20dm as shown in FIG. 7. Disk 20d can also double as a fan as well
as a micro disk enhanced air/fuel rotary mixer.
[0052] The above embodiments of the LCRGB 10 have the gaseous fuel
directed to the lower surface of turbulator disk 10d. However, as
shown in FIGS. 10A, 10B, and 10C, the gaseous fuel could also be
directed to the upper surface of the turbulator disk. Such an
arrangement would provide the added benefit of cooling the
turbulator disk to avoid overheating of the burner. The cooling of
the burner could be very important, especially for higher capacity
burner applications and in higher temperature burner environments.
Additionally, this embodiment will likely re-entrain products of
combustion and may have an effect on combustion similar to flue gas
recirculation resulting in low NOx production by the burner.
[0053] In the embodiment of LCRGB 10 of FIG. 10A, fuel gas inlet
pipe 10pe passes through turbulator disk 10w which is shaped as a
washer. A fuel deflecting cap 10c is positioned over outlet 10no of
nipple 10n of fuel pipe 10pe to deflect the fuel 180 degrees to
impinge upper surface 10wu of turbulator disk 10w. As described
previously, the jets of gaseous fuel entrain ambient air to provide
a self-sustaining combustible mixture of fuel and air which is then
ignited by CIM 10z.
[0054] A variation of the above described embodiment is shown in
FIG. 10C, wherein outlet 10no of nipple 10n is located relatively
close and generally parallel to upper surface 10wu of washer shaped
turbulator disk 10w. A deflecting disk 10g is located relatively
close to outlet 10no of nipple 10n to deflect the gaseous fuel 90
degrees over upper surface 10wu of disk 10w. As described
previously, the jets of gaseous fuel passing over surface 10wu of
disk 10w entrain ambient air to provide a self-sustaining
combustible mixture of fuel and air which is then ignited by CIM
10z.
[0055] It will be obvious to persons skilled in the art that other
raw materials in different proportions could be substituted for
those disclosed above to make the Low Cost Radial Gas Burner
element described above without departing from the spirit of the
invention.
[0056] All of these modifications to the above-described Low Cost
Radial Gas Burner are considered to fall within the scope of the
present invention.
* * * * *