US20080163614A1

US20080163614A1 - Turbulence Burner With Vortex Structures

Info

Publication number: US20080163614A1
Application number: US10/551,190
Authority: US
Inventors: James Bosket
Original assignee: Proto Technics Inc
Current assignee: PROTO-TECHNICS Inc; Proto Technics Inc
Priority date: 2005-08-12
Filing date: 2005-12-08
Publication date: 2008-07-10
Also published as: WO2007021259A1; CA2521018A1

Abstract

A fuel burning device includes a tubular combustion cylinder open at opposing first and second ends. A fuel inlet pipe has a first end extending through the first end of the combustion cylinder partially into the combustion cylinder and a second end extending outside of the combustion cylinder. The fuel burning device also includes a burner head connected to the first end of the fuel inlet pipe and an orifice connected between the burner head and the first end of the fuel inlet pipe. The burner head is structured and arranged so that combusted fuel discharged at the second end of said combustion cylinder has reduced CO and NOx emissions.

Description

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:

FIG. 1 shows a front view of a combustion cylinder according to a first embodiment;

FIG. 2 shows a front view of a combustion cylinder according to a second embodiment;

FIG. 3 shows a front view of a combustion cylinder according to a third embodiment;

FIG. 4 shows a top view of the combustion cylinder of FIG. 3;

FIG. 5 shows a front view of a combustion cylinder according to a fourth embodiment;

FIG. 6 shows a top view of the combustion cylinder of FIG. 5;

FIG. 7 shows a front view of a combustion cylinder according to a fifth embodiment;

FIG. 8 shows a top view of the combustion cylinder of FIG. 7;

FIG. 9 shows a front view of a combustion cylinder according to a sixth embodiment;

FIG. 10 shows a top view of the combustion cylinder of FIG. 9;

FIGS. 11 and 12 show the combustion cylinder of FIG. 9 rotated 90° and 180°, respectively, with respect to a longitudinal axis of the cylinder;

FIGS. 13 and 14 illustrate a front and top view, respectively, of a seventh embodiment having a multiple burner head;

FIGS. 15 and 16 illustrate a modification of the multiple burner head embodiment with the addition of external vortex fins;

FIGS. 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

FIGS. 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 FIG. 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 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 FIG. 1 permits 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 FIG. 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 FIG. 1.
The third embodiment illustrated in FIG. 3 and FIG. 4 shows the fuel inlet pipe 5 communicating with the air mixer body 6 through a threaded choke adjuster shaft 12. FIG. 4 is a view of the embodiment from the second extremity 3 through the combustion cylinder 1 toward the first extremity 2.
As seen in FIG. 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 20% 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 FIG. 1.
The fourth embodiment as illustrated in FIG. 5 and FIG. 6 shows a turbulence disk 14 attached to the exterior of the air mixer body 6. FIG. 6, similarly to FIG. 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 FIGS. 5 and 6, a pattern of turbulence with a curvilinear retrogradation develops in the secondary combustion air upstream of the ignition area of the 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 10, so that CO is practically eliminated while NOx emission is maintained at a reduced level.
The fifth embodiment as illustrated in FIG. 7 and FIG. 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 FIG. 8 being a same view as FIGS. 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 FIGS. 9 and 10 shows a confined cylindrical air guide aperture 16, with FIG. 10 being the same view as FIG. 8 in the fifth embodiment. Several vortex fins 17 project into the air guide 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.
FIGS. 11 and 12 completely illustrate the sixth embodiment of FIG. 9 with the view of FIG. 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.
FIGS. 13 and 14 illustrate a multiple burner head of the seventh embodiment. FIG. 14 is the same view as FIG. 10 of the prior embodiment. As seen in FIG. 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 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.
FIG. 15 and FIG. 16 illustrate the seventh embodiment with the addition of external vortex fins 19. FIG. 16 is the same view as FIG. 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.
FIG. 17 and FIG. 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 FIG. 18 being the same view as FIG. 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.
FIGS. 19 and 20 illustrate a ninth embodiment of the invention. In this embodiment, similar to the embodiment of FIGS. 17 and 18, the nozzle cap extends beyond the cylindrical air guide 15. However, in the ninth embodiment, the nozzle cap slots of FIG. 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.

Claims

1. A fuel burning device, comprising:

a tubular combustion cylinder open at opposing first and second ends;

a fuel inlet pipe having a first end extending through said first end of said combustion cylinder partially into the combustion cylinder and a second end extending outside of said combustion cylinder;

a hollow air mixing body having a proximal end in communication with said first end of said fuel inlet pipe, a distal end of said air mixing body having a hemispherical nozzle cap with a plurality of slots therethrough;

an orifice connected between said proximal end of said air mixing body and said first end of said fuel inlet pipe,

said proximal end of said air mixing body having a plurality of air inlet holes,

said air mixing body being structured and arranged at said first end of said combustion cylinder so that when fuel is burned, a naturally aspirated unregulated, turbulent forced air effect develops that increases the pressure at the plurality of air inlet holes so as to reduce CO and Nox emissions from the combusted fuel discharged at said second end of said combustion chamber.

2. The fuel burning device as claimed in claim 1, wherein there is a primary ignition of said fuel at said slots of said nozzle that creates a circular pattern of flame adjacent to an inner wall of said combustion cylinder.

3. The fuel burning device as claimed in claim 1, further comprising a positioning bracket connected to an exterior surface of said combustion cylinder and to said second end of said fuel inlet pipe, said bracket being adjustable to move said air mixing body toward said second end of said combustion cylinder.

4. The fuel burning device as claimed in claim 1, further comprising a choke adjuster shaft connected between said orifice and said fuel inlet pipe said shaft being adjustable to slow the speed of combustion gas through the combustion cylinder.

5. The fuel burning device as claimed in claim 4, further comprising a turbulence disk connected to an exterior surface of said air mixing body, said turbulence disk creating a first zone of turbulence above the turbulence disk in a direction of combustion gas exit and a different second zone of turbulence below the turbulence ring so as to create negative pressure at said plurality of nozzle cap slots, so that CO is practically eliminated and NOx emission is reduced, when the fuel is combusted.

6. The fuel burning device as claimed in claim 5, wherein said second zone of turbulence has a curvilinear retrogradation pattern.

7. The fuel burning device as claimed in claim 5, further comprising a hollow cylindrical air guide connected at a first extremity to said second end of said fuel inlet pipe, a second extremity of said air guide having an air guide aperture, an exterior surface of said mixing device and an interior surface of said air guide defining an area of secondary combustion.

8. The fuel burning device as claimed in claim 7, further comprising plural vortex fins projecting from said air guide at said second extremity and toward said aperture so as to form a respective vortex slot between an adjacent two of said plural vortex fins, a force of naturally aspirated rising air through said vortex slot creating helicoidal vortex air currents in said area of secondary combustion.

9. A fuel burning device, comprising:

a tubular combustion cylinder open at opposing first and second ends;

a burner head connected to said first end of said. fuel inlet pipe;

an orifice connected between said burner head and said first end of said fuel inlet pipe,

said burner head being structured and arranged at said first end of said combustion cylinder so that when fuel is burned, a naturally aspirated unregulated, turbulent forced air effect develops so that combusted fuel discharged at said second end of said combustion cylinder has reduced CO and NOx emissions,

10. The fuel, burning device according to claim 9, wherein said burner head comprises a hollow air mixing body having a proximal end in communication with said first end of said fuel inlet pipe, a distal end of said air mixing body having a hemispherical nozzle cap with a plurality of slots therethrough.

11. The fuel burning device according to claim 9, wherein said burner head comprises a hollow air mixing body having a proximal end in communication with said first end of said fuel inlet pipe, a distal end of said air mixing body having a conical nozzle cap with a plurality of holes therethrough, said nozzle cap having a lip which protrudes from said air mixing body.

12. A method of reducing carbon monoxide (CO) and oxides of nitrogen NOx emissions, comprising the steps of:

positioning a burner head nearer a first open end of a combustion cylinder surrounding said burner head than a second open end, so that a naturally aspirated, unregulated, turbulent forced air effect develops;

combusting an air/fuel mixture exiting from said burner head between said burner head and an inner wall of said combustion cylinder;

discharging the combusted fuel from said second end of said cylinder;

using the forced air effect to increase a pressure at air inlets of said burner head to reduce CO and NOx emissions due to the increased pressure.

13. The method of claim 12, further comprising the step placing an orifice adjacent said burner head to produce about 25,000 Btu at 11 inches water column supply pressure for propane gas.

14. The method of claim 12, further comprising the step of adjusting a bracket connected to an outside surface of the combustion cylinder to move the burner head closer to the second end of the combustion cylinder, which further increases the pressure at air inlets of the burner head so as to further reduce CO and NOx emissions.

15. The method as claimed in claim 12, further comprising the step of adjusting a choke adjuster disk connected through a choke adjuster shaft to a fuel inlet area of said burner head to create a venturi effect in the combustion cylinder, so as, to slow down a speed of combustion gas through the combustion cylinder to still further reduce Co and NOx emissions.

16. The method as claimed in claim 15, further comprising the step of attaching a turbulence disk to an exterior surface of said burner head to create two different zones of air pressure.

17. The method as claimed in claim 16, wherein a first one of said zones is above the turbulence disk in a direction of combusted fuel discharge and a second one of said zones is below the turbulence ring.

18. The method as claimed in claim 17, wherein the burner head comprises plural slots in the first zone, so that a pattern of turbulence with a curvilinear retrogradation develops in a secondary combustion air, upstream, in said direction of combusted fuel discharge, of an ignition area of said plural slots between said exterior surface of said burner head and an inner wall of said combustion cylinder.

19. The method as claimed in claim 18, further comprising the step of inserting a hollow cylindrical air guide into said combustion cylinder, between said burner head and said inner wall of the combustion cylinder, so as to define a secondary area of combustion between an inner wall of said air guide and said burner head and creating a tertiary area of combustion between an outer wall of said air guide and said inner wall of said combustion cylinder.

20. The method as claimed in claim 19, further comprising the step of creating vortex air currents by placing air vanes into the air guide, said vortex air currents substantially eliminating Co emission and further reducing NOx emissions.