U.S. patent application number 10/603871 was filed with the patent office on 2005-03-10 for burner fuel mixer head for concurrently burning two gaseous fuels.
Invention is credited to Westergaard, Per.
Application Number | 20050053887 10/603871 |
Document ID | / |
Family ID | 4171182 |
Filed Date | 2005-03-10 |
United States Patent
Application |
20050053887 |
Kind Code |
A1 |
Westergaard, Per |
March 10, 2005 |
Burner fuel mixer head for concurrently burning two gaseous
fuels
Abstract
A burner fuel mixer head includes a primary housing and a
secondary housing. The primary housing has a fuel/air mixing
chamber with a mixed fuel gas inlet. The secondary housing has a
fuel mixing chamber. A venturi throat with converging sidewalls is
positioned in the mixed fuel gas inlet of the primary housing. A
venturi nozzle communicates with a pressurized fuel gas inlet with
a first end of the venturi nozzle extending into the fuel mixing
chamber in axial alignment with the venturi throat. This forms a
venturi, such that a pressurized flow of pressurized fuel gas
through the venturi draws low pressure fuel gas from the fuel
mixing chamber of the secondary housing through the mixed fuel gas
inlet into the fuel/air mixing chamber of the primary housing.
Inventors: |
Westergaard, Per; (Islay,
CA) |
Correspondence
Address: |
DAVIS & BUJOLD, P.L.L.C.
FOURTH FLOOR
500 N. COMMERCIAL STREET
MANCHESTER
NH
03101-1151
US
|
Family ID: |
4171182 |
Appl. No.: |
10/603871 |
Filed: |
June 25, 2003 |
Current U.S.
Class: |
431/354 |
Current CPC
Class: |
F23D 14/62 20130101;
F23D 2204/00 20130101 |
Class at
Publication: |
431/354 |
International
Class: |
F23D 014/62 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 26, 2002 |
CA |
2,391,757 |
Claims
1. A burner fuel mixer head, comprising: a primary housing having a
fuel/air mixing chamber with a mixed fuel gas inlet, a combustion
air inlet, and a mixed fuel/air outlet communicating with the
fuel/air mixing chamber; a secondary housing having a fuel mixing
chamber with a pressurized fuel gas inlet and a low pressure fuel
gas inlet, the fuel mixing chamber of the secondary housing
communicating with the mixed fuel gas inlet leading into the
primary housing; a venturi throat with converging sidewalls
positioned in the mixed fuel gas inlet; a venturi nozzle
communicating with the pressurized fuel gas inlet, a first end of
the venturi nozzle extending into the fuel mixing chamber in axial
alignment with the venturi throat to form a venturi, such that a
pressurized flow of pressurized fuel gas through the venturi draws
low pressure fuel gas from the fuel mixing chamber of the secondary
housing through the mixed fuel gas inlet into the fuel/air mixing
chamber of the primary housing.
2. The burner fuel mixer head as defined in claim 1, wherein the
venturi nozzle is positioned in a pressurized fuel gas inlet
passage.
3. The burner fuel mixer head as defined in claim 2, wherein the
venturi nozzle is axially movable in the pressurized fuel gas inlet
passage, such that the venturi nozzle can be moved either toward or
away from the venturi throat to adjust the relative proportions of
pressurized fuel gas and low pressure fuel gas being fed through
the mixed fuel gas inlet into the fuel/air mixing chamber.
4. The burner fuel nozzle mixer head as defined in claim 3, wherein
the pressurized fuel gas inlet passage has an interior sidewall
with threads and a second end of the venturi nozzle has an exterior
surface with threads, such that the venturi nozzle is maintained in
threaded engagement with the interior sidewall of the pressurized
fuel gas inlet passage, rotation of the venturi nozzle resulting in
axial movement of the venturi nozzle in the pressurized fuel gas
inlet passage.
5. The burner mixer head as defined in claim 4, wherein the second
end of the venturi nozzle has a tool receiving receptacle, whereby
the venturi nozzle is rotated by means of a tool extended into the
pressurized fuel gas inlet passage and engaged with the tool
receiving receptacle.
6. The burner mixer head as defined in claim 4, wherein an
externally threaded lock nut is provided to maintain the axial
positioning of the venturi nozzle in the pressurized gas inlet
passage.
7. The burner mixed head as defined in claim 1, wherein the mixed
fuel/air outlet of the primary housing has converging sidewalls,
thereby providing a venturi which draws combustion air through the
combustion air inlet into the fuel/air mixing chamber.
8. A burner fuel mixer head, comprising: a primary housing having
an interior cavity defining a fuel/air mixing chamber, the primary
housing having a mixed fuel gas inlet, a combustion air inlet, and
a mixed fuel/air outlet all of which communicate with the interior
cavity; a secondary housing having an interior cavity defining a
fuel mixing chamber, the interior cavity of the secondary housings
communicating with the mixed fuel gas inlet leading into the
primary housing, the secondary housing having a pressurized fuel
gas inlet and a low pressure fuel gas inlet; a venturi throat with
converging sidewalls positioned in the mixed fuel gas inlet; a
pressurized fuel gas inlet passage leading from the pressurized
fuel gas inlet to the fuel mixing chamber of the secondary housing;
a venturi-nozzle positioned in the pressurized fuel gas inlet
passage and communicating with the pressurized fuel gas inlet, a
first end of the venturi nozzle extending into the fuel mixing
chamber in axial aligned with the venturi throat to form a venturi,
such that a pressurized flow of pressurized fuel gas through the
venturi draws low pressure fuel gas from the fuel mixing chamber of
the secondary housing through the mixed fuel gas inlet into the
fuel/air mixing chamber of the primary housing, the venturi nozzle
being axially movable in the pressurized fuel gas inlet passage,
such that the venturi nozzle can be moved either toward or away
from the venturi throat to adjust the relative proportions of
pressurized fuel gas and low pressure fuel gas being fed through
the mixed fuel gas inlet into the fuel/air mixing chamber, the
pressurized fuel gas inlet passage having an interior sidewall with
threads and a second end of the venturi nozzle having an exterior
surface with threads, such that the venturi nozzle is maintained in
threaded engagement with the interior sidewall of the pressurized
fuel gas inlet passage, rotation of the venturi nozzle resulting in
axial movement of the venturi nozzle in the pressurized fuel gas
inlet passage.
9. The burner mixer head as defined in claim 8, wherein the second
end of the venturi nozzle has a tool receiving receptacle, whereby
the venturi nozzle is rotated by means of a tool extended into the
pressurized fuel gas inlet passage and engaged with the tool
receiving receptacle.
10. The burner mixer head as defined in claim 8, wherein an
externally threaded lock nut is provided to maintain the axial
positioning of the venturi nozzle in the pressurized gas inlet
passage.
11. The burner mixed head as defined in claim 8, wherein the mixed
fuel/air outlet of the primary housing has converging sidewalls.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a burner fuel mixer head
for concurrently burning two gaseous fuels
BACKGROUND OF THE INVENTION
[0002] Most oil wells produce some low pressure raw gas. Formerly,
this low pressure raw gas was vented to atmosphere or diverted to a
flare pit. However, stricter environmental regulations have placed
limits on venting and flaring, which has lead to the use of this
low pressure raw gas as a fuel supply for firetube burners used in
various oil processing equipment. Burning raw gas at low pressure
(only 1 to 3 pounds per square inch) creates an unacceptable level
of emissions. It also heats the firetube unevenly; over heating the
close end of the firetube and not providing enough heat to the
remote end of the firetube. Therefore, in order to use the low
pressure raw gas as a primary fuel supply, the pressure is usually
increased by mixing the low pressure raw gas with a reliable source
of pressurized feed gas. The combustion efficiency of the burner
depends upon how well the low pressure raw gas can be fed to the
burner along with the pressurized feed gas.
SUMMARY OF THE INVENTION
[0003] What is required is a burner fuel mixer head that
effectively feeds low pressure raw gas to the burner with
pressurized feed gas.
[0004] According to the present invention there is provided a
burner fuel mixer head which includes a primary housing and a
secondary housing. The primary housing has an interior cavity
defining a fuel/air mixing chamber. The primary housing also has a
mixed fuel gas inlet, a combustion air inlet, and a mixed fuel/air
outlet all of which communicate with the interior cavity. The
secondary housing has an interior cavity defining a fuel mixing
chamber. The interior cavity of the secondary housings communicates
with the mixed fuel gas inlet leading into the primary housing. The
secondary housing has a pressurized fuel gas inlet and a low
pressure fuel gas inlet.
[0005] A venturi throat with converging sidewalls is positioned in
the mixed fuel gas inlet. A venturi nozzle communicates with the
pressurized fuel gas inlet with a first end of the venturi nozzle
extending into the fuel mixing chamber in axial alignment with the
venturi throat. This forms a venturi, such that a pressurized flow
of pressurized fuel gas through the venturi draws low pressure fuel
gas from the fuel mixing chamber of the secondary housing through
the mixed fuel gas inlet into the fuel/air mixing chamber of the
primary housing.
[0006] With the burner fuel mixer head, as described above,
pressurized fuel gas passing through the venturi draws low pressure
fuel gas from the fuel mixing chamber of the secondary housing into
the fuel/air mixing chamber of the primary housing.
[0007] Although beneficial results may be obtained through the use
of the burner fuel mixer head, as described above, the quantity of
low pressure gas produced varies from well to well. It is,
therefore, desirable that some means be provided for adjusting the
proportions of pressurized fuel gas and low pressure fuel gas. Even
more beneficial results may, therefore, be obtained when the
venturi nozzle is positioned in a pressurized fuel gas inlet
passage and the venturi nozzle is axially movable in the
pressurized fuel gas inlet passage, such that the venturi nozzle
can be moved either toward or away from the venturi throat to
adjust the relative proportions of pressurized fuel gas and low
pressure fuel gas being fed through the mixed fuel gas inlet into
the fuel/air mixing chamber.
[0008] There are various ways of making the venturi nozzle axially
adjustable in the pressurized fuel gas inlet passage. Beneficial
results have been obtained when the pressurized fuel gas inlet
passage has an interior sidewall with threads and a second end of
the venturi nozzle has an exterior surface with threads. This
enables the venturi nozzle to be maintained in threaded engagement
with the interior sidewall of the pressurized fuel gas inlet
passage. Rotation of the venturi nozzle results in axial movement
of the venturi nozzle in the pressurized fuel gas inlet passage. In
order to facilitate such adjustment it is preferred that the second
end of the venturi nozzle has a tool receiving receptacle. This
enables the venturi nozzle is rotated by means of a tool extended
into the pressurized fuel gas inlet passage and engaged with the
tool receiving receptacle.
[0009] In order to avoid unintended movement of the venturi nozzle,
it is preferred that an externally threaded lock nut be provided
which engages the threads in the pressurized fuel gas inlet passage
to maintain the axial positioning of the venturi nozzle.
[0010] It is also preferred that a venturi effect be created in the
fuel/air mixing chamber so that it draws combustion air
effectively. This is accomplished by providing the mixed fuel/air
outlet of the primary housing with converging sidewalls.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] These and other features of the invention will become more
apparent from the following description in which reference is made
to the appended drawings, the drawings are for the purpose of
illustration only and are not intended to in any way limit the
scope of the invention to the particular embodiment or embodiments
shown, wherein:
[0012] FIG. 1 is a side elevation view, in section, of a burner
fuel mixer head constructed in accordance with the teachings of the
present invention.
[0013] FIG. 2 is a side elevation view, in section, of a second
embodiment of a burner fuel mixer head constructed in accordance
with the teachings of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0014] The preferred embodiment, a burner fuel mixer head generally
identified by reference numeral 10, will now be described with
reference to FIG. 1.
[0015] Structure and Relationship of Parts:
[0016] Referring to FIG. 1, there is provided a burner fuel mixer
head 10 which includes a primary housing 12 and a secondary housing
14. Primary housing 12 has an interior cavity 16 that defines a
fuel/air mixing chamber 18. Primary housing 12 has a mixed fuel gas
inlet 20, a combustion air inlet 22, and a mixed fuel/air outlet 24
all of which communicate with interior cavity 16. Mixed fuel/air
outlet 24 of primary housing 12 has converging sidewalls 26.
[0017] Secondary housing 14 has an interior cavity 28 that also
defines a fuel mixing chamber 30. Interior cavity 28 of secondary
housing 14 communicates with mixed fuel gas inlet 20 leading into
primary housing 12. Secondary housing 14 has a pressurized fuel gas
inlet 32 and a low pressure fuel gas inlet 34.
[0018] A venturi throat 36 with converging sidewalls 38 is
positioned in mixed fuel gas inlet 20. A pressurized fuel gas inlet
passage 40 leads from pressurized fuel gas inlet 32 to fuel mixing
chamber 30 of secondary housing 14. A venturi nozzle 42 is
positioned in pressurized fuel gas inlet passage 40 and
communicates with pressurized fuel gas inlet 32. A first end 44 of
venturi nozzle 42 extends into fuel mixing chamber 30 in axial
alignment with venturi throat 36 to form a venturi generally
referenced by numeral 46, such that a pressurized flow of
pressurized fuel gas through venturi 46 draws low pressure fuel gas
from fuel mixing chamber 30 of secondary housing 14 through mixed
fuel gas inlet 20 into fuel/air mixing chamber 18 of primary
housing 12.
[0019] Pressurized fuel gas inlet passage 40 has an interior
sidewall 52 with threads 54 and a second end 48 of venturi nozzle
42 has an exterior surface 56 with threads 58, such that venturi
nozzle 42 is maintained in threaded engagement with interior
sidewall 52 of pressurized fuel gas inlet passage 40. Second end 48
of venturi nozzle 42 has a tool receiving receptacle 50, whereby
venturi nozzle 42 is rotated by means of a tool (not shown) that is
extended into pressurized fuel gas inlet passage 40 and engaged
with tool receiving receptacle 50. Rotation of venturi nozzle 42
results in axial movement of venturi nozzle 42 in pressurized fuel
gas inlet passage 40. Axially movement of venturi nozzle 42 in
pressurized fuel gas inlet passage 40 moves venturi nozzle 42
either toward or away from venturi throat 36 to adjust the relative
proportions of pressurized fuel gas and low pressure fuel gas being
fed through mixed fuel gas inlet 20 into fuel/air mixing chamber
18. An externally threaded lock nut 60 is provided to maintain the
axial positioning of venturi nozzle 42 in pressurized gas inlet
passage 40. Lock nut 60 also has a tool receiving receptacle
50.
[0020] Combustion air inlet 22 of primary housing 12 has a cover
plate 62. A portion of secondary housing 14 through which
pressurized gas inlet passage 40 extends has external threads 64.
Cover plate 62 is threadedly engaged with external threads 64 for
movement either toward or away from combustion air inlet 22, so
that the amount of combustion air fed into fuel/air mixing chamber
18 can be controlled. A screw 66 extends through an aperture 68 in
cover plate 62 and engages secondary housing 14 to serve as a
rotational stop which maintains cover plate 62 in a selected
rotational position. A coupling 70 and associated gasket 72 are
used to couple conduit (not shown) leading from a source of
pressurized gas to pressurized gas inlet passage 40.
[0021] It will be appreciated that venture nozzles 42 are
manufactured and installed at differing lengths depending on the
on-site specifications. Venturi nozzles 42 of secondary can be
either an adjustable venturi nozzle or a drop in venturi nozzle,
however both types of venturi nozzles 42 still require lock nut 60
to maintain the axial positioning of venturi nozzle 42 in
pressurized gas inlet passage 40.
[0022] Operation:
[0023] The use and operation of burner fuel mixer head 10 will now
be described with reference to FIG. 1. Referring to FIG. 1, burner
fuel mixer head 10 is used to effectively feed low pressure gas raw
gas and a pressurized gas feed.
[0024] High volume low pressure (1 oz-6 psi) gas that is supplied
through pressurized fuel gas inlet 32 is fed along pressurized fuel
gas passage 40 through venturi nozzle 42 creating a vacuum effect
in fuel mixing chamber 30, and then is passed through venturi
throat 36 with converging sidewalls 38 thus drawing preheated flue
gas in through low pressure fuel inlet 34.
[0025] In the event that preheating of flue gas is not required,
low pressure waste gas can be supplied through low pressure fuel
inlet 34. High volume low pressure gas of sufficient supply
pressure (1 oz-6 psi) and volume through fuel gas inlet 32 is fed
through venturi nozzle 42 creating a vacuum in fuel mixing chamber
30 and is then passed through venturi throat 36 with converging
sidewalls 38 drawing low pressure waste gas in through low pressure
fuel inlet 34.
[0026] Adjustments may be made by inserting a tool into tool
receptacle 50 on venturi nozzle 42. Through use of such a tool,
venturi nozzle 42 can be rotated to move axially within pressurized
fuel gas inlet passage 40 toward or away from venturi throat 36.
This permits adjustment of the relative proportions of pressurized
fuel gas and low pressure fuel gas being fed through mixed fuel gas
inlet 20 into fuel/air mixing chamber 18. Adjustments may be made
to the supply of combustion air by temporarily removing screw 66
which serves as a rotational stop for cover plate 62, and then
rotating cover plate 62 toward or away from combustion air inlet
22.
[0027] The advantages of burner fuel mixer head 10, as described
above are as follows;
[0028] it provides a high volume fuel gas for combustion at low
pressure.
[0029] it facilitates a high velocity flue gas flow even at low
fuel pressure.
[0030] it provides dual fuel capability (propane/solution gas/well
head gas/line gas) without burner readjustment.
[0031] it enables lower emissions and increased of combustion
efficiency while reducing the risk of firetube hot spots and flame
impingement.
[0032] it increases flue gas velocity with out increasing stack
discharge temperature.
[0033] it provides increased flue gas velocity to enhance thermal
efficiency and to reduce firetube hot spots and flame
impingement.
[0034] it eliminates mixer head freeze up in temperatures below 0
degrees Celcius.
[0035] it provides the ability to combust low pressure gases that
normally get vented into our atmosphere or burnt off in an
inefficient flare stack. These gases are not normally high enough
in volume to make it economical to compress them but they still
make up a sizeable portion of the environmental pollution today.
Now they can be a valuable fuel source with out any further
expenditures. This is possible because of the intense vacuum
created by this mixer head configuration.
[0036] A second embodiment of burner fuel mixer head generally
identified by reference numeral 100, will now be described with
reference to FIG. 2. The components of the second embodiment 100
will be identified by the same reference numerals as used in the
description above, so that only the differences need to be
identified and specifically described.
[0037] Structure and Relationship of Parts:
[0038] Referring to FIG. 2, there is provided a second embodiment
of burner fuel mixer head 100 which is adapted to be used where the
supply of gas is freezing. Second embodiment 100 is substantially
the same as first embodiment 10 except that with second embodiment
100 instead of coupling 70 and associated gasket 72 being used to
couple conduit (not shown) leading from a source of pressurized gas
to pressurized gas inlet passage 40, a third housing 110 with an
interior cavity 112 is threadably coupled with secondary housing
14. Interior cavity 112 defines a fuel mixing chamber 114. Third
housing 110 has a pressurized fuel gas inlet 116 and a low pressure
fuel gas inlet 118. A venturi nozzle 120 is positioned between
pressurized fuel gas inlet 116 and mixing chamber 114 in a
pressurized fuel gas inlet passage 122. Pressurized fuel gas inlet
passage 122 has an interior sidewall 124 with threads 126 and flow
nozzle 120 has an exterior surface 128 with threads 130, such that
venturi nozzle 120 is maintained in threaded engagement with
interior sidewall 124 of pressurized fuel gas inlet passage 122.
Rotation of venturi nozzle 120 results in axial movement of venturi
nozzle 120 in pressurized fuel gas inlet passage 122 to move
venturi nozzle 120 either toward or away from second end 48 of
venturi nozzle 42 in secondary housing 14 so as to adjust the
relative proportions of pressurized fuel gas and low pressure fuel
gas being fed through to mixing chamber 30 in secondary housing
14.
[0039] Interior cavity 116 of third housing 110 communicates with
mixing chamber 30 of second housing 14 via venturi nozzle 42.
Pressurized fuel gas inlet 32 is adapted to couple with conduit
(not shown) leading from a source of pressurized gas.
[0040] Operation:
[0041] With second embodiment 100, if high volume low pressure gas
entering through pressurized fuel gas inlet 116 is freezing in
mixing chamber 114, then supply of low pressure preheated fuel gas
can be moved from low pressure fuel inlet 34 in secondary housing
14 to low pressure fuel inlet 118 in third housing 110 without
jeopardizing the functioning of burner fuel mixer head 100. In this
situation, high volume low pressure gas of sufficient supply
pressure (1 oz-6 psi) and volume is supplied through pressurized
fuel gas inlet 116. High volume low pressure gas is fed through
flow nozzle 120 creating a vacuum in fuel mixing chamber 114. Fuel
mixture of high pressure low volume fuel gas and waste gas is then
passed through mixed fuel gas inlet 20 to create a vacuum in fuel
mixing chamber 30 of secondary housing 14.
[0042] In this patent document, the word "comprising" is used in
its non-limiting sense to mean that items following the word are
included, but items not specifically mentioned are not excluded. A
reference to an element by the indefinite article "a" does not
exclude the possibility that more than one of the element is
present, unless the context clearly requires that there be one and
only one of the elements.
[0043] It will be apparent to one skilled in the art that
modifications may be made to the illustrated embodiment without
departing from the spirit and scope of the invention as hereinafter
defined in the claims.
* * * * *