Note: Descriptions are shown in the official language in which they were submitted.
CA 02521018 2005-10-18
5566-1002
1
TURBULENCE BURNER WITH VORTEX STRUCTURES
FIELD OF THE INVENTION
The invention relates to a device and a method of
subjecting fuel/air premix to turbulent and vortex air currents
to reduce carbon monoxide (CO) and oxides of nitrogen(NOx)
emissions.
BRIEF SUMMARY OF THE INVENTION
An object of the invention is to provide a fuel burner
that reduces CO and Nox emissions.
Another object of the invention is to subject fuel/air
premix to a naturally aspirated pattern of turbulent air having
a curvilinear retrogradation and areas of helicoidal vortex
currents of air to eliminate CO while further reducing NOx
emissions.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, features and advantages of the
invention will become more apparent after reading the following
detailed description of the preferred embodiment of the
invention, given with reference to the accompanying drawings, in
which:
CA 02521018 2005-10-18
2
Figure 1 shows a front view of a combustion cylinder
according to a first embodiment;
Figure 2 shows a front view of a combustion cylinder
according to a second embodiment;
Figure 3 shows a front view of a combustion cylinder
according to a third embodiment;
Figure 4 shows a top view of the combustion cylinder
of Figure 3;
Figure 5 shows a front view of a combustion cylinder
according to a fourth embodiment;
Figure 6 shows a top view of the combustion cylinder
of Figure 5;
Figure 7 shows a front view of a combustion cylinder
according to a fifth embodiment;
Figure 8 shows a top view of the combustion cylinder
of Figure 7;
Figure 9 shows a front view of a combustion cylinder
according to a sixth embodiment;
Figure 10 shows a top view of the combustion cylinder
of Figure 9;
Figures 11 and 12 show the combustion cylinder of
Figure 9 rotated 90° and 180°, respectively, with respect
to a
longitudinal axis of the cylinder;
CA 02521018 2005-10-18
3
Figures 13 and 14 illustrate a front and top view,
respectively, of a seventh embodiment having a multiple burner
head;
Figures 15 and 16 illustrate a modification of the
multiple burner head embodiment with the addition of external
vortex fins;
Figures 17 and 18 illustrate a front and top view,
respectively, of an eighth embodiment with the burner head
raised so that the nozzle cap slots 10 are outside the
cylindrical air guide; and
Figures 19 and 20 illustrate a front and top view,
respectively, of a ninth embodiment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A fuel burner as shown in the first embodiment of
Figure 1 includes a tubular combustion cylinder 1 open at a
first extremity 2 and a second extremity 3. A fuel inlet pipe 5
projects slightly into the combustion cylinder and connects to a
hollow air mixer body 6. An orifice 7 communicates from the fuel
inlet pipe 5 into the air mixer body 6.
The air mixer body 6 has a proximal end and a distal
end. The air mixer body 6 has three primary air inlet holes 8 at
the proximal end. One of ordinary skill in the art would
recognize that the number and size of such holes may be varied
CA 02521018 2005-10-18
4
in relation to the size of the orifice 7. The distal end of the
air mixer body 6, farthest from the first extremity 2,
terminates in a hemispherical nozzle cap 9. The cap 9 has seven
nozzle cap slots 10. The number and area of the slots may be
varied by one skilled in the art in relation to the size of the
orifice 7 and the primary air inlet holes 8.
Primary ignition of fuel at the nozzle cap slots 10
creates a circular pattern of flame adjacent to an inner wall 4
of the combustion cylinder 1. The combusted fuel discharges at
the second extremity 3. Since the air mixer body 6 is positioned
at the first extremity 2 of the combustion cylinder 1, an
unregulated, turbulent forced air effect develops. In addition,
the exterior of the air mixer body 6 and the inner wall 4
together define a secondary area of unregulated, turbulent air
for combustion. This turbulent forced air effect increases the
pressure at the primary air inlets 8 and reduced CO and NOx
emission result.
The air mixer body 6, primary air inlet holes 8 and
nozzle cap slots 10 may be referred to in totality as a type of
burner head. Commercially engineered burner heads of this type
are typically engineered to yield 7,500 British Thermal Units
(Btu) at 11 inches water column (w.c.) supply pressure for
propane gas in free air burn. The embodiment in Figure 1 permits
CA 02521018 2005-10-18
an orifice size producing 25,000 Btu at the same supply pressure
of propane. As appreciated by one of ordinary skill in the art,
reference to propane as a fuel is illustrative without any
intent to limit the types of fuel, which may be combusted in
this burner with reduced CO and NOx emissions.
Reduced CO and NOx emissions are obtained by each of
the embodiments of the invention. The second embodiment shown in
Figure 2 illustrates a moveable assemble bracket 11 that is
attached to the exterior of the combustion cylinder 1 and the
fuel inlet pipe 5. The manner of attachment and movement may
vary without limiting the scope of the invention. The bracket 11
is adjustable to enable the air mixer body 6 to be positioned
closer to the second extremity 3 of the combustion cylinder 1.
When the air mixer body 6 is closer to the second extremity 3,
the pressure at the primary air inlet holes 8 increases, so that
the resultant combustion reduces CO and NOx emissions even
further than in the embodiment of Figure 1.
The third embodiment illustrated in Figure 3 and
Figure 4 shows the fuel inlet pipe 5 communicating with the air
mixer body 6 through a threaded choke adjuster shaft 12. Figure
4 is a view of the embodiment from the second extremity 3
through the combustion cylinder 1 toward the first extremity 2.
CA 02521018 2005-10-18
6
As seen in Figure 3, a choke adjuster disk 13 with
mating thread is attached to the choke adjuster shaft 12. The
choke adjuster disk 13 creates a venturi effect as it is
regulated. Such regulation also varies the degree of turbulence
of secondary combustion air. This embodiment can be operated
with varying percentages of excess air, typically ranging from
3% to 20o for various applications and at various altitudes of
sea level. Regulation of the choke adjuster disk 13 also slows
the speed of combustion gas through the combustion cylinder 1,
so that CO and NOx emissions are further reduced as compared to
the embodiment of Figure 1.
The fourth embodiment as illustrated in Figure 5 and
Figure 6 shows a turbulence disk 14 attached to the exterior of
the air mixer body 6. Figure 6, similarly to Figure 4 is a view
of the embodiment from the second extremity 3 through the
combustion cylinder 1 toward the first extremity 2. In this
embodiment, two different zones of air pressure in the regulated
turbulent secondary combustion air develop after primary
ignition. One zone is above and one below the turbulence disk
14.
In the embodiment of Figures 5 and 6, a pattern of
turbulence with a curvilinear retrogradation develops in the
secondary combustion air upstream of the ignition area of the
CA 02521018 2005-10-18
7
nozzle cap slots 10. Although the pattern of turbulence occurs,
flame stability is maintained. In addition, positive pressure at
the primary air inlet holes 8 is increased and a negative
pressure develops at the nozzle cap slots 10. These changes in
pressure improve flame lift-off above the nozzle cap slots l0,
so that CO is practically eliminated while NOx emission is
maintained at a reduced level.
The fifth embodiment as illustrated in Figure 7 and
Figure 8 shows a hollow cylindrical air guide 15 attached to the
fuel inlet pipe 5 terminating closest to the second extremity 3
in an air guide aperture 16, with Figure 8 being a same view as
Figures 4 and 6 as noted above. The exterior of the air mixer
body 6 and interior of the cylindrical air guide 15 define an
area of secondary combustion. The interior of the cylindrical
air guide 15 confines the pattern of turbulence in the secondary
combustion air at the ignition area of the nozzle cap slots 10,
so that the pressure increases further at the primary air inlet
holes 8 resulting in further reduction of Nox emission, while CO
is still practically eliminated.
The sixth embodiment as illustrated in Figures 9 and
l0 shows a confined cylindrical air guide aperture 16, with
Figure 10 being the same view as Figure 8 in the fifth
embodiment. Several vortex fins 17 project into the air guide
CA 02521018 2005-10-18
8
aperture 16 closer to the second extremity 3. Vortex slots 18
fill the interstices between the vortex fins 17. The force of
the naturally aspirated rising air through the vortex slots
creates an area of helicoidal vortex air currents in the
secondary combustion air. The low-flow velocities of vortex air
currents in this area further entrain the fuel-air premix and
improve combustion. As a consequence, CO emissions remain
practically eliminated (as in the prior embodiment), yet NOx
emissions are further reduced.
Figures 11 and 12 completely illustrate the sixth
embodiment of Figure 9 with the view of Figure 11 rotated 90
degrees on the vertical axis. These views are included to more
clearly show that air guide 15 is hollow and includes an opening
closer to the first extremity 2.
One skilled in the art may of course proportionately
scale the various orifices, interstices and structures to
increase or decrease the amount of input fuel and resulting
output Btu power.
Figures 13 and 14 illustrate a multiple burner head of
the seventh embodiment. Figure 14 is the same view as Figure 10
of the prior embodiment. As seen in Figure 13, a lower fuel feed
fixture 11B and an upper fuel feed fixture 11C are attach to a
fuel feed bracket 11A. The amount of excess combustion air in
CA 02521018 2005-10-18
9
this embodiment can also be adjusted. Intake holes in an upper
choke disk 13A are aligned through rotation over the intake
holes in a lower choke disk 13B. As illustrated the intake holes
are fully aligned and opened.
Figure 15 and Figure 16 illustrate the seventh
embodiment with the addition of external vortex fins 19. Figure
16 is the same view as Figure 14 of the prior embodiment. The
external vortex fins 19 protrude into a tertiary combustion air
flow between the outside of the cylindrical air guide 15 and the
combustion cylinder inner wall 4. A further complimentary area
of helicoidal vortex currents result in the cooler tertiary
combustion air. Lower combustion temperature further reduces NOx
emission.
Figure 17 and Figure 18 illustrate an eighth
embodiment with the burner head raised in the cylindrical air
guide 15 such that the nozzle cap slots 10 are closer to the
second extremity 3 and outside the cylindrical air guide 15,
with Figure 18 being the same view as Figure 16 of the prior
embodiment. In this embodiment, the flame thereby spreads wider
in closer proximity to the combustion cylinder inner wall 4.
Flame entrainment with the slower and cooler airflow velocities
of the helicoidal vortex currents in the tertiary combustion air
further minimize NOx emissions.
CA 02521018 2005-10-18
Figures 19 and 20 illustrate a ninth embodiment of the
invention. In this embodiment, similar to the embodiment of
Figures 17 and 18, the nozzle cap extends beyond the cylindrical
air guide 15. However, in the ninth embodiment, the nozzle cap
slots of Figure 18 are replaced by a plurality of nozzle cap
holes 21. In addition, the nozzle cap 9' is conical instead of
hemispherical. The nozzle cap 9' has a nozzle cap lip 20 that
protrudes from the air mixer body 6. The nozzle cap lip 20
produces a pattern of turbulence with a curvilinear
retrogradation without the addition of a turbulence disk 14 to
the air mixer body 6.
In each of the embodiments of the invention, NOx
reduction is achieved without use of devices such as laterally
injected combustion air forming a secondary torroidal
recirculation zone in the combustion cylinder 1 further
downstream of the primary combustion area. In addition, CO
emissions are practically eliminated.
While the present invention has been described in
connection with various preferred embodiments thereof, it is to
be understood that those embodiments are provided merely to
illustrate the invention, and should not be used as a pretext to
limit the scope of protection conferred by the true scope and
spirit of the appended claims.
