U.S. patent application number 13/336276 was filed with the patent office on 2012-08-09 for gas turbine engine and fuel injection system.
Invention is credited to Jushan Chin, Mohan K. Razdan, Thomas Richardson, Nader K. Rizk, Duane Smith.
Application Number | 20120198850 13/336276 |
Document ID | / |
Family ID | 46599726 |
Filed Date | 2012-08-09 |
United States Patent
Application |
20120198850 |
Kind Code |
A1 |
Chin; Jushan ; et
al. |
August 9, 2012 |
GAS TURBINE ENGINE AND FUEL INJECTION SYSTEM
Abstract
One embodiment of the present invention is a unique gas turbine
engine. Another embodiment is a unique fuel injection system for a
gas turbine engine. Other embodiments include apparatuses, systems,
devices, hardware, methods, and combinations for gas turbine
engines and fuel injection systems for gas turbine engines. Further
embodiments, forms, features, aspects, benefits, and advantages of
the present application will become apparent from the description
and figures provided herewith.
Inventors: |
Chin; Jushan; (Irvine,
CA) ; Rizk; Nader K.; (Carmel, IN) ;
Richardson; Thomas; (Indianapolis, IN) ; Razdan;
Mohan K.; (Indianapolis, IN) ; Smith; Duane;
(Carmel, IN) |
Family ID: |
46599726 |
Appl. No.: |
13/336276 |
Filed: |
December 23, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61427726 |
Dec 28, 2010 |
|
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Current U.S.
Class: |
60/738 |
Current CPC
Class: |
F23R 3/14 20130101; F23R
3/343 20130101; F23R 3/28 20130101 |
Class at
Publication: |
60/738 |
International
Class: |
F23R 3/28 20060101
F23R003/28 |
Claims
1. A gas turbine engine, comprising: a compressor system; a turbine
system; and a combustion system fluidly disposed between the
compressor system and the turbine system, the combustion system
including a combustion liner and a fuel injection system operative
to inject fuel into the combustion liner, wherein the fuel
injection system includes: a pilot injection module having a pilot
nozzle and a pilot swirler for the pilot nozzle, wherein the pilot
swirler is operative to induce swirl to enhance mixing of fuel and
air for the pilot injection module; and a main injection module
disposed radially outward of the pilot injection module, wherein
the main injection module includes a main fuel injector; a main
swirler; and a deswirler, wherein the main fuel injector includes a
plurality of nozzles operative to discharge fuel radially outward;
wherein the main swirler is operative to induce swirl to enhance
mixing of fuel and air for the main fuel injector; and wherein the
deswirler is operative to reduce swirl induced by the main
swirler.
2. The gas turbine engine of claim 1, wherein the deswirler is
located radially outward of the main swirler.
3. The gas turbine engine of claim 1, wherein the main fuel
injector includes a plurality of plain-jet nozzles.
4. The gas turbine engine of claim 3, further comprising a main
fuel manifold, wherein at least one of the plain-jet nozzles
extends outward in a radial direction from the main fuel
manifold.
5. The gas turbine engine of claim 3, wherein at least one of the
plain-jet nozzles has a discharge opening disposed in the main
swirler.
6. The gas turbine engine of claim 1, further comprising a first
fuel supply line; and a second fuel supply line that is fluidly
independent of the first fuel supply line, wherein the pilot nozzle
is fluidly coupled to the first fuel supply line; and wherein the
main fuel injector is fluidly coupled to the second fuel supply
line.
7. The gas turbine engine of claim 1, wherein the fuel injection
system is configured to selectively supply fuel to one or both of
the pilot injection module and the main injection module.
8. A fuel injection system for a gas turbine engine, comprising: a
main injection module including a plurality of plain-jet nozzles; a
main swirler; and a deswirler; wherein at least one of the
plain-jet nozzles is operative to discharge fuel radially outward;
wherein the main swirler is operative to induce swirl to enhance
mixing of fuel and air for the main injection module; and wherein
the deswirler is operative to reduce swirl induced by the main
swirler; and a pilot injection module disposed radially inward of
the main injection module, wherein the pilot injection module
includes a pilot nozzle and a pilot swirler for the pilot nozzle,
wherein the pilot swirler is operative to induce swirl to enhance
mixing of fuel and air for the pilot injection module.
9. The fuel injection system of claim 8, wherein the deswirler
includes a non-swirling air passage.
10. The fuel injection system of claim 8, wherein the main
injection module includes an annular discharge nozzle for
discharging a fuel air mixture.
11. The fuel injection system of claim 8, wherein the main
injection module includes a discharge nozzle for discharging a fuel
air mixture, further comprising a plurality of air injection
openings positioned to inject air into the main injection module
upstream of the discharge nozzle.
12. The fuel injection system of claim 8, further comprising a ramp
configured to direct an air fuel mixture from the main injection
module in a radially outward direction.
13. The fuel injection system of claim 12, wherein the ramp is
conical.
14. The fuel injection system of claim 8, further comprising a
separating member disposed around the pilot nozzle and positioned
between the pilot nozzle and the main injection module.
15. The fuel injection system of claim 14, wherein the separating
member is configured to shield the pilot nozzle from combustion
heat.
16. The fuel injection system of claim 8, wherein the at least one
of the plain-jet nozzles is configured to inject fuel directly into
the main swirler.
17. A fuel injection system for a gas turbine engine, comprising: a
pilot injection module having a pilot nozzle operative to produce a
pilot combustion zone; and a main injection module having a fuel
distribution manifold; a plurality of main nozzles extending from
the fuel distribution manifold for injecting fuel; a main swirler;
and a deswirler, wherein the main swirler is operative to induce
swirl into fuel and air in the main injection module; and wherein
the deswirler is operative to reduce swirl induced by the main
swirler.
18. The fuel injection system of claim 17, further comprising a
heat shield disposed around the pilot injection module and
positioned between the pilot injection module and the main
injection module.
19. The fuel injection system of claim 17, wherein the main nozzles
are plain-jet nozzles oriented with a directional component
extending radially outward of the pilot nozzle.
20. The fuel injection system of claim 17, wherein the main
injection module is configured to produce a main combustion zone
disposed radially outward of the pilot combustion zone.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims benefit of U.S. Provisional
Patent Application No. 61/427,726, filed Dec. 28, 2010, entitled
GAS TURBINE ENGINE AND FUEL INJECTION SYSTEM, which is incorporated
herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to gas turbine engines, and
more particularly, to fuel injection systems for gas turbine
engines.
BACKGROUND
[0003] Gas turbine engines and fuel injection systems for gas
turbine engines remain an area of interest. Some existing systems
have various shortcomings, drawbacks, and disadvantages relative to
certain applications. Accordingly, there remains a need for further
contributions in this area of technology.
SUMMARY
[0004] One embodiment of the present invention is a unique gas
turbine engine. Another embodiment is a unique fuel injection
system for a gas turbine engine. Other embodiments include
apparatuses, systems, devices, hardware, methods, and combinations
for gas turbine engines and fuel injection systems for gas turbine
engines. Further embodiments, forms, features, aspects, benefits,
and advantages of the present application will become apparent from
the description and figures provided herewith.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The description herein makes reference to the accompanying
drawings wherein like reference numerals refer to like parts
throughout the several views, and wherein:
[0006] FIG. 1 schematically illustrates some aspects of a
non-limiting example of a gas turbine engine in accordance with an
embodiment of the present invention.
[0007] FIG. 2 depicts some aspects of a non-limiting example of
combustion system in accordance with an embodiment of the present
invention.
[0008] FIG. 3 depicts some aspects of a non-limiting example of a
fuel injection system in accordance with an embodiment of the
present invention.
DETAILED DESCRIPTION
[0009] For purposes of promoting an understanding of the principles
of the invention, reference will now be made to the embodiments
illustrated in the drawings, and specific language will be used to
describe the same. It will nonetheless be understood that no
limitation of the scope of the invention is intended by the
illustration and description of certain embodiments of the
invention. In addition, any alterations and/or modifications of the
illustrated and/or described embodiment(s) are contemplated as
being within the scope of the present invention. Further, any other
applications of the principles of the invention, as illustrated
and/or described herein, as would normally occur to one skilled in
the art to which the invention pertains, are contemplated as being
within the scope of the present invention.
[0010] Referring to the drawings, and in particular FIG. 1, a
non-limiting example of a gas turbine engine 10 in accordance with
an embodiment of the present invention is depicted. In one form,
engine 10 is an aircraft propulsion power plant. In other
embodiments, engine 10 may be a land-based or marine engine. In one
form, engine 10 is a multi-spool turbofan engine. In other
embodiments, engine 10 may be a single or multi-spool turbofan,
turboshaft, turbojet, turboprop gas turbine or combined cycle
engine.
[0011] Gas turbine engine 10 includes a fan system 12, a compressor
system 14, a diffuser 16, a combustion system 18 and a turbine
system 20. Compressor system 14 is in fluid communication with fan
system 12. Diffuser 16 is in fluid communication with compressor
system 14. Combustion system 18 is fluidly disposed between
compressor system 14 and turbine system 20. Fan system 12 includes
a fan rotor system 22. In various embodiments, fan rotor system 22
includes one or more rotors (not shown) that are powered by turbine
system 20 and operative to pressurize air. Compressor system 14
includes a compressor rotor system 24. In various embodiments,
compressor rotor system 24 includes one or more rotors (not shown)
that are powered by turbine system 20 and operative to further
pressurize air received from fan system 12. Turbine system 20
includes a turbine rotor system 26. In various embodiments, turbine
rotor system 26 includes one or more rotors (not shown) operative
to drive fan rotor system 22 and compressor rotor system 24.
Turbine rotor system 26 is driving coupled to compressor rotor
system 24 and fan rotor system 22 via a shafting system 28. In
various embodiments, shafting system 28 includes a plurality of
shafts that may rotate at the same or different speeds and in the
same or different directions. In some embodiments, only a single
shaft may be employed.
[0012] During the operation of gas turbine engine 10, air is drawn
into the inlet of fan system 12 and pressurized by fan system 12.
Some of the air pressurized by fan system 12 is directed into
compressor system 14, and the balance is directed into a bypass
duct (not shown) for providing a component of the thrust output by
gas turbine engine 10. Compressor system 14 further pressurizes the
air received from fan system 12, which is then discharged in to
diffuser 16. Diffuser 16 reduces the velocity of the pressurized
air, and directs the diffused airflow into combustion system 18.
Fuel is mixed with the pressurized air in combustion system 18,
which is then combusted. In one form, combustion system 18 includes
a combustion liner (not shown) that contains a continuous
combustion process. In other embodiments, combustion system 18 may
take other forms, and may be, for example, a wave rotor combustion
system, a rotary valve combustion system, or a slinger combustion
system, and may employ deflagration and/or detonation combustion
processes. The hot gases exiting combustion system 18 are directed
into turbine system 20, which extracts energy in the form of
mechanical shaft power to drive fan system 12 and compressor system
14 via shafting system 28. The hot gases exiting turbine system 20
are directed into a nozzle (not shown), and provide a component of
the thrust output by gas turbine engine 10.
[0013] Referring to FIG. 2, combustion system 18 includes a
combustion liner 30 and a fuel injection system 32. Combustion
liner 30 is disposed in a combustor case 34. Combustion liner 30 is
operative to contain combustion processes during the operation of
engine 10. Fuel injection system 32 is operative to inject fuel
into combustion liner 30. In particular, fuel injection system 32
is operative to inject a fuel/air mixture into combustion liner 30,
which is ignited by an igniter (not shown) to form a combustion
process 36 that adds heat to the air discharged by compressor
system 14. The heated air is then discharged by combustion system
18 into turbine system 20.
[0014] Referring to FIG. 3 in conjunction with FIG. 2, fuel
injection system 32 includes a pilot injection module 38 and a main
injection module 40. Main injection module 40 is disposed
concentrically around pilot injection module 38, i.e., radially
outward of pilot injection module 38. Pilot injection module 38,
disposed radially inward of main injection module 40, is configured
inject a pilot fuel flow 42 to generate a pilot combustion process
44. Main injection module 40 is configured to inject a main fuel
flow 46 to generate a main combustion process 48 disposed around
pilot combustion process 44. In one form, pilot injection module 38
and main injection module 40 are independently operable. During low
power operation of engine 10, e.g., including ground idle and
flight idle conditions, pilot injection module 38 is employed. Main
injection module 40 is employed during high power engine 10
operation, e.g., including take-off and cruise thrust. Some
operating regimes include the use of both pilot injection module 38
and main injection module 40, e.g., during transition from idle or
other low power conditions to higher power conditions. In some
embodiments, both main injection module 40 and pilot injection
module 38 may be employed to inject fuel into combustion liner 30
during high power engine 10 operation. In other embodiments, only
main injection module 40 is employed during high power engine 10
operation.
[0015] Pilot injection module 38 is fluidly coupled to a fuel
supply line 50. Main injection module 40 is fluidly coupled to a
fuel supply line 52. Fuel supply lines 50 and 52 are fluidly
independent of each other, that is, one supply line may be
pressurized to supply fuel to the corresponding injection module
independent of the other fuel supply line. In one form, fuel
injection system 32 is configured to selectively control fuel
delivery (including fuel pressure) to fuel supply lines 50 and 52,
providing independent control of pilot injection module 38 and main
injection module 40 to selectively supply fuel to one or both of
pilot injection module 38 and main injection module 40. In other
embodiments, pilot injection module 38 and main injection module 40
may be fluidly coupled to a common fuel supply line, and may be
selectively and independently operable via other means. In still
other embodiments, pilot injection module 38 and main injection
module 40 may not be independently operable as such. In one form,
pilot injection module 38 is optimized for operation in low engine
10 power conditions, and main injection module 40 is optimized for
operation in high engine 10 power conditions. In other embodiments,
pilot injection module 38 and main injection module 40 may be
optimized for operation at other engine 10 power conditions.
[0016] Pilot injection module 38 includes a pilot nozzle 54, a
pilot swirler 56 and a discharge nozzle 58. Pilot nozzle 54 is in
fluid communication with fuel supply line 50. Pilot nozzle 54 is
operative to inject fuel into combustion liner 30. In one form,
pilot nozzle 54 is a pressure swirl atomizer. In other embodiments,
pilot nozzle 54 may take other forms. In one form, pilot swirler 56
surrounds pilot nozzle 54. In other embodiments, pilot swirler 56
may be arranged in other locations and orientations. In one form,
pilot swirler 56 includes a plurality of turning vanes 60
configured to induce swirl into airflow passing through pilot
swirler 56. In other embodiments, other means for inducing swirl
may be employed, e.g., air injection and/or fuel injection ports
configured to induce swirl.
[0017] The swirling pilot airflow from pilot swirler 56 mixes with
the fuel sprayed by pilot nozzle 54. In one form, pilot injection
module 38 is configured to mix pilot fuel spray and air before
injection into the combustion zone. The swirl induced by pilot
swirler 56 enhances the mixing of fuel and air for pilot injection
module 38, e.g., relative to systems that do not employ swirlers.
The amount of swirl may vary with the application. The fuel
discharged from pilot nozzle 54 and the air passing through pilot
swirler 56 are discharged into combustion liner 30 via discharge
nozzle 58. In one form, discharge nozzle 58 is circular in shape.
In other embodiments, discharge nozzle 58 may be shaped
differently.
[0018] Main injection module 40 includes a main fuel injector 62, a
main swirler 64, a deswirler 66 and a discharge nozzle 68. Main
fuel injector 62 is in fluid communication with fuel supply line
52. Main fuel injector 62 is operative to inject fuel for mixing
with air and combustion in combustion liner 30. In one form, main
fuel injector 62 is configured to indirectly inject fuel into
combustion liner 30, via swirler 64. In other embodiments, main
fuel injector 62 may be configured to directly inject fuel into
combustion liner 30, e.g., similar to pilot nozzle 54.
[0019] Main fuel injector 62 includes a fuel manifold 70 and
plurality of main fuel nozzles 72. In one form, manifold 70 is a
distribution annulus formed in main fuel injector 62 and disposed
radially outward of and circumferentially around pilot injection
module 38. In other embodiments, fuel manifold 70 may take other
forms. Fuel manifold 70 is in fluid communication with fuel supply
line 52. Fuel nozzles 72 are in fluid communication fuel manifold
70. In one form, fuel nozzles 72 are plain-jet nozzles. In other
embodiments, other nozzle types may be employed in addition to or
in place of plain-jet nozzles. In one form, nozzles 72 extend
outward in a radial direction from manifold 70. In the example
depicted in FIG. 3, nozzles 72 extend both radially outward and
aft. In other embodiments, nozzles 72 may extend in other
directions in addition to or in place of radial and/or aft
directions. In one form, nozzles 72 are configured to discharge
fuel radially outward, that is, having a radially outward flow
direction component. In the example depicted in FIG. 3, nozzles 72
are configured to discharge fuel both radially outward and aft. In
other embodiments, nozzles 72 may be configured to discharge fuel
in other directions in addition to or in place of radial and/or aft
directions. In some embodiments, some nozzles 72 may be configured
to discharge fuel in one direction, whereas others may be
configured to discharge fuel in one or more other directions.
[0020] Main swirler 64 is configured to induce swirl in order to
enhance the mixing of fuel and air for main fuel injector 62. In
one form, main swirler 64 is an axial swirler. In other
embodiments, main swirler 64 may take one or more other forms. In
one form, main swirler 64 includes a plurality of turning vanes 74
configured to induce swirl into airflow passing through main
swirler 64. In other embodiments, other means for inducing swirl
may be employed, e.g., air injection and/or fuel injection ports
configured to induce swirl. In one form, nozzles 72 include
discharge openings 76 disposed in main swirler 64, and are
operative to inject fuel directly into main swirler 64. In other
embodiments, some or all of discharge openings 76 may be disposed
elsewhere.
[0021] Deswirler 66 is configured to reduce swirl induced by main
swirler 64. In one form, deswirler 66 is disposed radially outward
of main swirler 64. In other embodiments, deswirler 66 may be
positioned in other locations and orientations. In one form,
deswirler 66 includes a non-swirling air passage. In a particular
form, deswirler 66 is configured to form an annular non-swirling
air stream disposed around the swirling fuel and air discharged by
main swirler 64, to reduce the exit swirl angle of the fuel and air
discharged through discharge nozzle 68. In other embodiments, other
means for reducing swirl may be employed.
[0022] Discharge nozzle 68 is operative to discharge the air fuel
mixture, generated by main injection module 40, into combustion
liner 30. In one form, discharge nozzle 68 is a converging nozzle.
In other embodiments, discharge nozzle 68 may take other forms. In
one form, discharge nozzle 68 includes contraction ramps 80 and 82
extending to and forming a throat 84. In one form, ramps 80 and 82
are conical. In other embodiments, ramps 80 and 82 may take other
forms. In some embodiments, only a single contraction ramp may be
employed. The air fuel mixture generated by main injection module
40 is injected into combustion liner 30 via discharge nozzle 68. In
one form, discharge nozzle 68 is annular in shape, extending
concentrically around pilot injection module 38 and discharge
nozzle 58. In other embodiments, discharge nozzle 68 may take other
forms. In one form, ramps 80 and 82 are configured to direct the
air fuel mixture from main injection module 40 in a radially
outward direction, that is, in a direction having a radially
outward component from pilot injection module 38. In one form,
discharge nozzle 68 includes a plurality of air injection openings
86 spaced apart circumferentially around the periphery of discharge
nozzle 68, located aft of deswirler 66 and forward of contraction
ramp 80. Air injection openings 86 are positioned to injection air
into main injection module 40 upstream of discharge nozzle 68. In
other embodiments, air injection openings may be disposed in other
locations. Air injection openings 86 may take any convenient shape.
Some embodiments may not include air injection openings 86.
[0023] Disposed between pilot nozzle 54 and main injection module
40 is a separating member 88. In one form, separating member 88 is
configured as a heat shield to shield pilot nozzle 54 from heat
generated during the combustion of fuel.
[0024] Embodiments of the present invention include a gas turbine
engine, comprising: a compressor system; a turbine system; and a
combustion system fluidly disposed between the compressor system
and the turbine system, the combustion system including a
combustion liner and a fuel injection system operative to inject
fuel into the combustion liner, wherein the fuel injection system
includes: a pilot injection module having a pilot nozzle and a
pilot swirler for the pilot nozzle, wherein the pilot swirler is
operative to induce swirl to enhance mixing of fuel and air for the
pilot injection module; and a main injection module disposed
radially outward of the pilot injection module, wherein the main
injection module includes a main fuel injector; a main swirler; and
a deswirler, wherein the main fuel injector includes a plurality of
nozzles operative to discharge fuel radially outward; wherein the
main swirler is operative to induce swirl to enhance mixing of fuel
and air for the main fuel injector; and wherein the deswirler is
operative to reduce swirl induced by the main swirler.
[0025] In a refinement, the deswirler is located radially outward
of the main swirler.
[0026] In another refinement, the main fuel injector includes a
plurality of plain-jet nozzles.
[0027] In yet another refinement, the engine further comprises a
main fuel manifold, wherein at least one of the plain-jet nozzles
extends outward in a radial direction from the main fuel
manifold.
[0028] In still another refinement, at least one of the plain-jet
nozzles has a discharge opening disposed in the main swirler.
[0029] In yet still another refinement, the engine further
comprises a first fuel supply line; and a second fuel supply line
that is fluidly independent of the first fuel supply line, wherein
the pilot nozzle is fluidly coupled to the first fuel supply line;
and wherein the main fuel injector is fluidly coupled to the second
fuel supply line.
[0030] In a further refinement, the fuel injection system is
configured to selectively supply fuel to one or both of the pilot
injection module and the main injection module.
[0031] Embodiments of the present invention include a fuel
injection system for a gas turbine engine, comprising: a main
injection module including a plurality of plain-jet nozzles; a main
swirler; and a deswirler; wherein at least one of the plain-jet
nozzles is operative to discharge fuel radially outward; wherein
the main swirler is operative to induce swirl to enhance mixing of
fuel and air for the main injection module; and wherein the
deswirler is operative to reduce swirl induced by the main swirler;
and a pilot injection module disposed radially inward of the main
injection module, wherein the pilot injection module includes a
pilot nozzle and a pilot swirler for the pilot nozzle, wherein the
pilot swirler is operative to induce swirl to enhance mixing of
fuel and air for the pilot injection module.
[0032] In a refinement, the deswirler includes a non-swirling air
passage.
[0033] In another refinement, the main injection module includes an
annular discharge nozzle for discharging a fuel air mixture.
[0034] In yet another refinement, the main injection module
includes a discharge nozzle for discharging a fuel air mixture,
further comprising a plurality of air injection openings positioned
to inject air into the main injection module upstream of the
discharge nozzle.
[0035] In still another refinement, the system further comprises a
ramp configured to direct an air fuel mixture from the main
injection module in a radially outward direction.
[0036] In yet still another refinement, the ramp is conical.
[0037] In a further refinement, the system further comprises a
separating member disposed around the pilot nozzle and positioned
between the pilot nozzle and the main injection module.
[0038] In a yet further refinement, the separating member is
configured to shield the pilot nozzle from combustion heat.
[0039] In a still further refinement, the at least one of the
plain-jet nozzles is configured to inject fuel directly into the
main swirler.
[0040] Embodiments of the present invention include a fuel
injection system for a gas turbine engine, comprising: a pilot
injection module having a pilot nozzle operative to produce a pilot
combustion zone; and a main injection module having a fuel
distribution manifold; a plurality of main nozzles extending from
the fuel distribution manifold for injecting fuel; a main swirler;
and a deswirler, wherein the main swirler is operative to induce
swirl into fuel and air in the main injection module; and wherein
the deswirler is operative to reduce swirl induced by the main
swirler.
[0041] In a refinement, the system further comprises a heat shield
disposed around the pilot injection module and positioned between
the pilot injection module and the main injection module.
[0042] In another refinement, the main nozzles are plain-jet
nozzles oriented with a directional component extending radially
outward of the pilot nozzle.
[0043] In still another refinement, the main injection module is
configured to produce a main combustion zone disposed radially
outward of the pilot combustion zone.
[0044] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment(s), but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims, which
scope is to be accorded the broadest interpretation so as to
encompass all such modifications and equivalent structures as
permitted under the law. Furthermore it should be understood that
while the use of the word preferable, preferably, or preferred in
the description above indicates that feature so described may be
more desirable, it nonetheless may not be necessary and any
embodiment lacking the same may be contemplated as within the scope
of the invention, that scope being defined by the claims that
follow. In reading the claims it is intended that when words such
as "a," "an," "at least one" and "at least a portion" are used,
there is no intention to limit the claim to only one item unless
specifically stated to the contrary in the claim. Further, when the
language "at least a portion" and/or "a portion" is used the item
may include a portion and/or the entire item unless specifically
stated to the contrary.
* * * * *