Fluid sprinkling – spraying – and diffusing – Combining of separately supplied fluids – Including whirler device to induce fluid rotation
Reexamination Certificate
2000-07-26
2001-07-17
Scherbel, David A. (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Combining of separately supplied fluids
Including whirler device to induce fluid rotation
C239S405000, C239S406000, C239S418000, C239S461000, C239S490000, C239S474000, C239S475000
Reexamination Certificate
active
06260773
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to a novel air-atomizing oil and/or gas burner utilizing a low pressure fan, and a three-piece air-atomizing nozzle suitable for use therein. More particularly, it relates to such a novel burner which is configured to provide a uniform mixing of atomized fuel (i.e., oil and/or gas) and air for consistent ignition and efficient combustion.
Conventional air-atomizing oil burners offer the benefit of partially mixing oil with air prior to discharge from an orifice of a nozzle allowing the burner to operate at low firing rates compared to conventional oil burners which incorporate a pressure atomizing nozzle. In an air-atomizing oil burner, oil passes through the air-atomizing nozzle for combining with a high velocity air stream prior to discharge of atomized oil and air from the nozzle. Typically, a compressor supplies pressurized air at about 10 psi to about 100 psi to provide the required high velocity air supply.
With conventional air-atomizing oil burners, the high cost and unreliability of air compressors has limited the use of air-atomizing oil burners for residential heating. A recent attempt has been made to provide a low firing rate, air-atomizing oil burner suitable for residential heating that uses a low pressure fan powered by an expensive brushless DC motor to supply air at a pressure of about 6 to 12 inches of water (0.21 psi to 0.92 psi). Drawbacks with such air-atomizing oil burners are the complexity and high cost associated with fabricating the air-atomizing nozzle and the inability to regulate the supply of the low pressure air from the fan to provide a stable uniform mixture of atomized oil and air for consistent ignition and efficient combustion.
For example,
FIG. 1
shows a diagrammatic illustration of a prior art air-atomizing oil burner
10
having a low pressure fan
12
which provides a primary air supply, a secondary air supply, and a tertiary air supply. Primary air passes through air-atomizing nozzle
20
, secondary air passes through a back plate
14
and a retention plate
16
, and tertiary air passes between back plate
14
and air cone
18
. As best seen in
FIG. 2
, a drawback with this prior art design is that a plurality of holes
19
in back plate
14
produce high pressure points. The turbulent air which exits holes
19
rushes toward retention plate
16
and discharges out louvers
17
. This turbulent secondary air which exits louvers
17
unevenly mixes with the discharge of atomized oil and air from nozzle
20
resulting in inconsistent ignition and uneven combustion.
As shown in
FIG. 3
, air-atomizing nozzle
20
in burner
10
comprises an outer body
21
, an end cap
24
, a swirler
26
, an inner body
22
, a fuel distributer
23
fitted to inner body
22
, and a pair of O-rings
28
. Thus, this prior art nozzle requires six separate parts which must be precisely machined and subsequently assembled together which obviously makes it relatively expensive.
SUMMARY OF THE INVENTION
Accordingly, it is the object of the present invention to provide a low cost marketable air-atomizing oil and/or gas burner utilizing a low pressure fan which is desirably suitable for residential heating and configured to provide a generally uniform mixture of air and atomized fuel (i.e., oil and/or gas) to enable consistent ignition and efficient combustion.
It is also an object of the present invention to provide an air-atomizing fuel oil (i.e., and/or gas) burner in which the flow of secondary air is stabilized prior to combining with atomized oil to provide a generally uniform mixture of air and atomized fuel (i.e., oil and/or gas) enabling consistent ignition and efficient combustion.
It is another object of the present invention to provide such a burner in which secondary air is metered into a chamber at about 90 degrees to the direction from which the secondary air exits the chamber to mix with atomized oil and/or gas.
It is another object of the present invention to provide such a burner in which secondary air aids flame retention.
It is another object of the present invention to provide such a burner in which secondary air directs an ignition spark toward the combustible fuel/air mixture during ignition.
It is still another object of the present invention to provide such a burner in which a low pressure fan and oil pump are powered by a single motor.
It is yet another object of the present invention to provide such a burner having a low cost three-piece air-atomizing nozzle.
It is a further object of the present invention to provide such a burner that is may be manufactured easily and inexpensively for widespread use in residential heating systems.
Certain of the foregoing related objects are also achieved in an air-atomizing fuel burner comprising:
an air-tube;
an air-atomizing nozzle disposed in said air-tube, said nozzle having a longitudinally extending axis;
a conduit for supplying a combustible fuel to said nozzle;
a fan for providing a supply of air to said air-tube; and
means for metering the supply of air in said air-tube to provide a primary supply of air to said nozzle and a secondary supply of air around said nozzle, said metering means defining a chamber into which secondary air is directed inwardly toward said axis of said nozzle.
Certain of the foregoing related objects are also achieved in a three-piece air-atomizing nozzle comprising:
a fuel distributor having a fuel passageway extending therethrough, said fuel distributor having a discharge end having at least one aperture extending from said fuel passageway and opening onto an outer surface of said discharge end;
a tubular outer body attachable to said fuel distributor and spaced from said discharge end of said fuel distributor to define a primary air passageway, said outer body having at least one inlet for receiving primary air into, and at least one outlet for discharging primary air from, said air passageway; and
a swirler extending between said outer body and said discharge end of said fuel distributor, said swirler spaced-apart from said discharge end of said fuel distributor to define a fuel atomizing passageway, said swirler having at least one inlet for receiving a first portion of the primary air into said fuel atomizing passageway and an atomized fuel discharge outlet, and said swirler having a plurality of vanes spaced between said swirler and said outer body for imparting a swirling motion to a second portion of the primary air.
Certain of the foregoing related objects are also achieved in a method for atomizing oil with air for combustion, comprising the steps of:
arranging an air-atomizing nozzle in an air-tube, said nozzle having a longitudinally extending axis;
feeding a supply of fuel to said nozzle for discharge therefrom;
feeding a supply of air to said air-tube for discharge therefrom, such that atomized fuel is mixed with air for combustion; and
metering said supply of air in said air-tube to provide a primary supply of air to said nozzle and a secondary supply of air around said nozzle, such that said secondary air is directed inwardly toward said axis of said nozzle.
REFERENCES:
patent: 2163915 (1939-06-01), Reif et al.
patent: 2219696 (1940-10-01), Mueller et al.
patent: 3570242 (1971-03-01), Leonardi et al.
patent: 3644077 (1972-02-01), Dimick
patent: 4221558 (1980-09-01), Santisi
patent: 4431403 (1984-02-01), Nowak et al.
patent: 4595143 (1986-06-01), Simmons et al.
patent: 4842197 (1989-06-01), Simon et al.
Evans Robin O.
Galgano & Burke
Scherbel David A.
LandOfFree
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