U.S. patent application number 14/558069 was filed with the patent office on 2016-06-02 for systems and methods for reducing pipeline erosion using acoustic radiation.
This patent application is currently assigned to CHEVRON U.S.A. INC.. The applicant listed for this patent is Farid G. Mitri. Invention is credited to Farid G. Mitri.
Application Number | 20160153249 14/558069 |
Document ID | / |
Family ID | 56078858 |
Filed Date | 2016-06-02 |
United States Patent
Application |
20160153249 |
Kind Code |
A1 |
Mitri; Farid G. |
June 2, 2016 |
Systems and Methods for Reducing Pipeline Erosion Using Acoustic
Radiation
Abstract
An acoustic brake system includes one or more transducers
configured to couple to an external wall of a pipe. The one or more
transducers are configured to generate a standing wave within the
pipe. The standing wave comprises one or more nodes within the
pipe. When a particulate-laden fluid flows through the pipe, a
plurality of particulates move towards the nodes and away from a
wall of the pipe. The acoustic brake system also includes a
function generator electrically coupled to the one or more
transducers and configured to drive the one or more
transducers.
Inventors: |
Mitri; Farid G.; (Santa Fe,
NM) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Mitri; Farid G. |
Santa Fe |
NM |
US |
|
|
Assignee: |
CHEVRON U.S.A. INC.
San Ramon
CA
|
Family ID: |
56078858 |
Appl. No.: |
14/558069 |
Filed: |
December 2, 2014 |
Current U.S.
Class: |
166/380 ;
166/65.1 |
Current CPC
Class: |
E21B 43/12 20130101;
E21B 17/1007 20130101 |
International
Class: |
E21B 17/10 20060101
E21B017/10 |
Claims
1. An acoustic brake system, comprising: one or more transducers
configured to couple to an external wall of a pipe, wherein the one
or more transducers generate an acoustic standing wave within the
pipe, the acoustic standing wave comprising one or more nodes
within the pipe, wherein when a particulate-laden fluid flows
through the pipe, a plurality of particulates move towards the
nodes and away from a wall of the pipe; and a function generator
electrically coupled to the one or more transducers and configured
to drive the one or more transducers.
2. The acoustic brake system of claim 1, wherein the waveform
matches a resonant frequency of the pipe.
3. The acoustic brake system of claim 1, wherein the one or more
transducers has ring shape, a strip shape, a sheet shape, a spot
shape, or any combination thereof.
4. The acoustic brake system of claim 1, where a plurality of
transducers are configured to generate waveforms of the same
frequency.
5. The acoustic brake system of claim 1, wherein a plurality of
transducers are configured to generate waveforms of one or more
different frequencies.
6. The acoustic brake system of claim 1, wherein the acoustic
standing wave creates one or more relatively high and relatively
low pressure regions, wherein the one or more low pressure regions
are away from the wall of the pipe, and wherein the plurality of
particulates gather at or near the one or more low pressure
regions.
7. The acoustic brake system of claim 1, wherein the acoustic
standing wave creates an ultrasonic field within the pipe, wherein
when the particulate-laden fluid flows through the pipe, the
ultrasonic field creates an acoustic radiation force on a plurality
of particulates which slows down the speed of the plurality of
particulates and pushes the plurality of particulates away from the
wall of the pipe.
8. An acoustic brake system, comprising: one or more transducers
coupled to a wall of a pipe, the one or more transducers configured
to generate an ultrasonic field within the pipe, wherein when a
particulate-laden fluid flows through the pipe, the ultrasonic
field creates an acoustic radiation force on a plurality of
particulates which pushes the plurality of particulates away from a
wall of the pipe; and a function generator electrically coupled to
the one or more transducers and configured to drive the one or more
transducers.
9. The acoustic brake system of claim 8, wherein the one or more
transducers form one or more rings around the pipe.
10. The acoustic brake system of claim 8, wherein the ultrasonic
field creates one or more relatively high and relatively low
pressure regions, wherein the one or more low pressure regions are
away from the wall of the pipe, and wherein the plurality of
particulates gather at or near the one or more low pressure
regions.
11. The acoustic brake system of claim 8, wherein the one or more
transducers are disposed on or adjacent to a curved portion of the
pipe.
12. The acoustic brake system of claim 8, wherein the ultrasonic
field has a waveform which matches a resonant frequency of the
pipe.
13. The acoustic brake system of claim 8, wherein the one or more
transducers are disposed on an external wall of the pipe.
14. The acoustic break system of claim 8, wherein the one or more
transducers are actuated in a burst-mode.
15. The acoustic break system of claim 8 wherein the one or more
transducers are actuated continuously.
16. The acoustic break system of claim 8 wherein the one or more
transducers are actuated through amplitude-modulation.
17. The acoustic break system of claim 8 wherein the one or more
transducers are actuated through frequency modulation.
18. The acoustic break system of claim 8, wherein the one or more
transducers are disposed within the pipe.
19. A method of reducing particulate impact in a pipe, comprising:
coupling an acoustic brake system to an external wall of a pipe,
the acoustic brake system comprising one or more transducers;
coupling the one or more transducers to the external wall of the
pipe; transmitting a signal from the function generator to the one
or more transducers; generating a standing wave within the pipe,
the standing wave comprising one or more nodes; and pushing a
plurality of particulates towards the one or more nodes and away
from a wall of the pipe when a particulate-laden fluid flows
through the pipe.
20. The method of claim 19, comprising: generating an ultrasonic
field within the pipe; creating one or more relatively high and
relatively low pressure regions, wherein the one or more low
pressure regions are away from the wall of the pipe, and forcing
the plurality of particulates towards the one or more low pressure
regions.
21. The method of claim 19, wherein the standing wave matches a
resonant frequency of the pipe.
22. The method of claim 19, where a plurality of the one or more
transducers are configured to generate waveforms of the same
frequency or of one or more different frequencies.
Description
TECHNICAL FIELD
[0001] The present application relates to reducing pipeline
erosion. Specifically, the present application relates to reducing
pipeline erosion by slowing down erosion-causing particulates using
acoustic radiation forces.
BACKGROUND
[0002] Production fluid that enters hydrocarbon production systems
often contains an amount of particulates, such as sand particles,
from surrounding formations. These particulates flow through the
pipes and can impact or stick onto the walls of the pipes. This can
contribute to erosion, wear, or damage of the pipes and other
equipment. Indeed, erosion has been long recognized as a potential
source of failure in oil and gas production systems. In particular,
elbow and curved portions of piping are especially susceptible to
erosion from particulates in the fluid flow due to the inertia
effects of traveling particulates. However, detection of erosion as
it progresses can be very difficult and plant operators rarely have
an adequate measure of the internal conditions of the pipelines in
their systems. This makes erosion management extremely tedious and
sometimes impractical. Therefore, it is very important to develop
new tools, efficient methods and advanced technologies to reduce
erosion in pipes. Presently, some means of reducing erosion include
reduction of the rate of fluid flow through production piping,
which reduces the velocity of the particulates, or designing pipes
that reduce flow velocity and minimize elbow or curved pipe
portions. However, such techniques reduce the overall speed of
production, which has financial implications and drawbacks. Another
method is the use of sand screens or gravel packs to filter
particulates out of the production stream. However, some
particulates are so small that these particulates are able to
travel through the sand screens, and generate a significant amount
of erosion. Thus, existing techniques for reducing erosion due to
particulates do not provide an adequate solution.
SUMMARY
[0003] In general, in one aspect, the disclosure relates to an
acoustic brake system. The acoustic brake system includes one or
more transducers configured to couple to an external wall of a
pipe. The one or more transducers are configured to generate a
standing wave within the pipe. The standing wave comprises one or
more nodes within the pipe. When a particulate-laden fluid flows
through the pipe, a plurality of particulates move towards the
nodes and away from a wall of the pipe. The acoustic brake system
also includes a function generator electrically coupled to the one
or more transducers and configured to drive the one or more
transducers.
[0004] In another aspect, the disclosure can generally relate to an
acoustic brake system. The acoustic brake system includes one or
more transducers coupled to an external wall of a pipe. The one or
more transducers are configured to generate an ultrasonic field
within the pipe such that when a particulate-laden fluid flows
through the pipe, the ultrasonic field creates an acoustic
radiation force on a plurality of particulates. The force pushes
the plurality of particulates away from a wall of the pipe. The
acoustic brake system also includes a function generator
electrically coupled to the one or more transducers and configured
to drive the one or more transducers.
[0005] In another aspect, the disclosure can generally relate to a
method of reducing particulate impact in a pipe. The method
includes coupling an acoustic brake system to an external wall of a
pipe, the acoustic brake system comprising one or more transducers.
The method further includes coupling the one or more transducers to
the external wall of the pipe. The method also includes
transmitting a signal from the function generator to the one or
more transducers. The method further includes generating a standing
wave within the pipe, the standing wave comprising one or more
nodes. The method also includes pushing a plurality of particulates
towards the one or more nodes and away from a wall of the pipe when
a particulate-laden fluid flows through the pipe.
[0006] These and other aspects, objects, features, and embodiments
will be apparent from the following description and the appended
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] The drawings illustrate only example embodiments of the
present disclosure, and are therefore not to be considered limiting
of its scope, as the disclosures herein may admit to other equally
effective embodiments. The elements and features shown in the
drawings are not necessarily to scale, emphasis instead being
placed upon clearly illustrating the principles of the example
embodiments. Additionally, certain dimensions or positions may be
exaggerated to help visually convey such principles. In the
drawings, reference numerals designate like or corresponding, but
not necessarily identical, elements. In one or more embodiments,
one or more of the features shown in each of the figures may be
omitted, added, repeated, and/or substituted. Accordingly,
embodiments of the present disclosure should not be limited to the
specific arrangements of components shown in these figures.
[0008] FIG. 1 illustrates a schematic diagram of an example
application of an acoustic brake system used in a downhole
environment, in accordance with example embodiments of the present
disclosure.
[0009] FIG. 2 illustrates a cross-sectional representation of a
first example behavior of particulates in a pipe having an acoustic
brake system disposed thereon, in accordance with example
embodiments of the present disclosure.
[0010] FIG. 3 illustrates another cross-sectional representation of
a second example behavior of particulates in a pipe having the
acoustic brake system disposed thereon, in accordance with example
embodiments of the present disclosure.
[0011] FIG. 4 illustrates the behavior of particulates as the
particulates flow through a segment of pipe having the acoustic
brake system disposed thereon, in accordance with example
embodiments of the present disclosure.
[0012] FIG. 5 illustrates a cross-sectional view looking down a
pipe showing a particulate-laden fluid within the pipe under
influence of the acoustic brake system, in accordance with example
embodiments of the present disclosure.
[0013] FIG. 6 illustrates an example configuration of an acoustic
brake system, in which the acoustic brake system includes multiple
transducers formed as rings around a pipe, in accordance with
example embodiments of the present disclosure.
[0014] FIG. 7 illustrates another example embodiment of an acoustic
brake system, in which the acoustic brake system includes a
transducer strip disposed along a length of a segment of pipe, in
accordance with example embodiments of the present disclosure.
[0015] FIG. 8 illustrates another example configuration of an
acoustic brake system, in which the acoustic brake system includes
a first transducer sheet and a second transducer sheet disposed
around a pipe, in accordance with example embodiments of the
present disclosure.
[0016] FIG. 9 is a flow chart illustrating a method of reducing
particulate impact in a pipe, in accordance with example
embodiments of the present disclosure.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
[0017] Example embodiments directed to systems and methods for
reducing pipeline erosion using acoustic radiation will now be
described in detail with reference to the accompanying figures.
Like, but not necessarily the same or identical, elements in the
various figures are denoted by like reference numerals for
consistency. In the following detailed description of the example
embodiments, numerous specific details are set forth in order to
provide a more thorough understanding of the disclosure herein.
However, it will be apparent to one of ordinary skill in the art
that the example embodiments disclosed herein may be practiced
without these specific details. In other instances, well-known
features have not been described in detail to avoid unnecessarily
complicating the description. The example embodiments illustrated
herein include certain components that may be replaced by alternate
or equivalent components in other example embodiments as will be
apparent to one of ordinary skill in the art. Example embodiments
discussed in the present disclosure are directed towards downhole
production piping applications. Such examples are employed to
exhibit features of the present disclosure in context, and not as a
limitation on the application of the systems and methods of the
present disclosure. In practice, the systems and techniques
disclosed herein have applications in subterranean environments,
underwater environments, and above-ground systems.
[0018] Referring now to the drawings, FIG. 1 illustrates an example
application of an acoustic brake system 102. Specifically, FIG. 1
illustrates a schematic diagram of a well site 100 in which the
acoustic brake system 102 is disposed on a production pipe 106, in
accordance with example embodiments of the present disclosure. In
certain example embodiments, a wellbore 108 is formed in a
subterranean formation 118 and coupled to a rig 110 on a surface
112 of the formation 118. The formation 118 can include one or more
of a number of formation types, including but not limited to shale,
limestone, sandstone, clay, sand, and salt. The surface 112 may be
ground level for an on-shore application or the sea floor for an
off-shore application. In certain embodiments, a subterranean
formation 118 can also include one or more reservoirs in which one
or more resources (e.g., oil, gas, water, steam) are located. In
certain example embodiments, the wellbore 108 is cased with cement
or other casing material, which is perforated to allow fluids to
flow from the formation 118 into the well 108. The production
tubing 106 is disposed downhole within the well 108 and fluids
enter the production tubing 106 from the well 108. Fluids are
recovered and brought to the rig 110 through the production tubing
106. In certain example embodiments, a production packer 105 is
coupled to the production tubing 106. Although FIG. 1 illustrates
an example downhole application of an acoustic brake system 102, in
practice, the acoustic brake system 102 can be used in surface or
underwater applications as well, including but not limited to
refinery pipe systems, flow loops, and the like.
[0019] The production fluid travelling through the production
tubing 106 may contain particulates which can cause erosion and
wear on the production tubing 106. In certain example embodiments,
the acoustic brake system 102 is disposed in an annular space 114
around a portion of the production tubing 106. In certain such
example embodiments, the acoustic brake system 102 is disposed
around the production tubing 106 at an elbow 116 in the production
tubing 106. The acoustic brake system 102 slows down and mildly
suspends the particulates in the fluid as the fluid and
particulates flow through the elbow 116 portion of the production
tubing 106. This reduces the impact of the particulates onto the
inner walls of the production tubing 106, which reduces erosion and
wear on the production tubing 106. In certain example embodiments,
the transducers can be disposed on portions of the production
tubing 106 downstream of the elbow 116, which is also relatively
susceptible to the impact of the traveling particulates. In other
example embodiments, the acoustic brake system 102 and its
transducers can be disposed on any portion of the production tubing
106. In certain example embodiments, transducers can be placed
along the entire length of the production tubing 106, continuously
or in segments. In certain example embodiments, the acoustic brake
system 102 includes one or more transducers, which emit acoustic
waves into the production tubing 106 to suspend the particulates,
as is further described below with reference to FIGS. 2-4. The
acoustic brake system 102 can also have a variety of configurations
and positions, an example set of which is described below with
reference to FIGS. 6-8.
[0020] FIG. 2 illustrates a cross-sectional representation 200 of a
pipe 202 having an acoustic brake system 102 disposed thereon, in
accordance with example embodiments of the present disclosure.
Specifically, the acoustic brake system 102 includes a transducer
206 configured to generate a standing wave having a single node 204
within the pipe 202. In certain example embodiments, the standing
wave has a frequency that matches one of the resonant frequencies
of the pipe 202. In certain example embodiments, the transducer 206
is coupled non-intrusively to the pipe. Nodes refer to the points
in the standing wave with the smallest amplitude. In certain
example embodiments, the transducer 206 emits an acoustic wave from
a first side 208a of the pipe 202 which reflected back from a
second side 208b of the pipe 202, forming the standing wave.
Particulates 210 in the fluid flowing through the pipe 202 are
forced towards the node 204 and away from the walls of the pipe 202
as the particulates 210 flow past the acoustic brake system 102. In
certain example embodiments, the node 204 represents a low pressure
region within the pipe 202. In certain example embodiments, the
travel velocity of the particulates 210 decreases when traveling
through the standing wave. The particulates 210 go from being
randomly scattered to gathering at the node 204. In certain example
embodiments, the remaining fluid is unaffected by the standing wave
and thus flows at the normal velocity. As such, the particulates
210 are slowed down without slowing down the speed of production or
fluid recovery.
[0021] In certain example embodiments, the transducer 206 is
coupled to a function generator 212, which outputs a signal to
excite the transducer 206 and implement the standing wave within
the pipe 202. In certain example embodiments, the transducer 206 is
tuned to emit a frequency which matches one of the pipe's resonant
frequencies. This ensures optimal ultrasound transmission through
the pipe wall. The transmitted frequencies produce an ultrasonic
field in the pipe 206, which creates an acoustic radiation force on
the particulates in the flow. In certain example embodiments, this
force keeps the particulates from impacting and/or sticking to the
pipe wall where erosion might occur. In certain example
embodiments, the force reduces the speed at which the particulates
impact the pipe wall, which decreases the likelihood of adhesion to
the pipe. Specifically, the acoustical radiation force pushes the
particulates away from the pipe wall, gathering at the node 210
instead.
[0022] The function generator can be preprogrammed or controlled to
output a signal that implements a standing wave having the
parameters suitable for a specific application. For example, the
amplitude, phase, and frequency of the signal generated by the
function generator can be determined and set to implement a
standing wave having such characteristics. In certain example
embodiments, the one or more transducers are actuated through
amplitude-modulation. In other example embodiments, the one or more
transducers are actuated through frequency modulation.
[0023] FIG. 3 illustrates another cross-sectional representation
300 of a pipe 202 having the acoustic brake system 102 disposed
thereon, in accordance with example embodiments of the present
disclosure. Specifically, the acoustic brake system 102 of FIG. 3
includes a transducer 206 configured to generate a waveform forming
two nodes 204 within the pipe 202. Thus, the particulates 210
gather at the two nodes 204 and away from the walls of the pipe
202. In such an example embodiment, the particulates 210 that flow
through the standing wave are attracted towards the closest node
204. In certain example embodiments, the transducer 206 can be
configured to generate a waveform forming any number of nodes 204
within the pipe 202, and positioned at various locations within the
pipe 202. The number and location of the nodes 204 may be
determined based on various factors, including the size of the pipe
202, speed of flow, and expected amount and size of particulates,
among others. In certain example embodiments, a plurality of the
one or more transducers 206 generate waveforms of the same
frequency. In certain other example embodiments, a plurality of the
one or more transducers 206 generate different frequencies.
Generating different frequencies can help trap particulates of
different sizes.
[0024] FIG. 4 illustrates the behavior of particulates 210 as the
particulates 210 flow through a segment of pipe 202 having the
acoustic brake system 102 disposed thereon, in accordance with
example embodiments of the present disclosure. Reference number 402
refers to the initial behavior of particulates 210 as the
particulates enter the segment of pipe in which the acoustic brake
system 102 generates a standing wave. At this point, the
particulates 210 are dispersed in the fluid in their natural state,
with some particulates 210 touching or near the walls of the pipe
202.
[0025] Reference number 404 refers to the behavior of the
particulates 210 quickly after the particulates 210 have entered
the segment of pipe 202 having the standing wave, in which the
particulates have begun to move towards the nodes 204 of the
standing wave and away from the walls of the pipe. For example, in
a certain application, the time is approximately 0.5 ms after the
particulates 210 enter the segment of pipe 202. The timing
parameter is provides as an illustration and for context only. In
practice, the timing can vary depending on various parameters and
conditions of the system.
[0026] Reference number 406 refers to the behavior of the
particulates 210 after the particulates 210 have been in the
segment of pipe 202 a period of time longer than that of 404. At
this point, the particulates 210 have gathered at the nodes 210 and
away from the walls of the pipe 202. For example, in a certain
application, the time is approximately 5 ms after the particulates
210 enter the segment of pipe 202. As the particulates 210 flow
through the remainder of the segment of pipe 202 having the
acoustic brake system 102, the particulates 210 flow along the
nodes 210 and away from the walls of the pipe 202 until the
particulates 210 exit the segment of pipe 202 having the standing
wave. In certain example embodiments, the acoustic brake system 102
is placed at elbow or curved portions of pipes as these regions are
more susceptible to particulate impact due to the inertial effect
on the particulates 210 at these points. In certain example
embodiments, the acoustic brake system 102 can be placed anywhere
on a pipe.
[0027] FIG. 5 illustrates a cross-sectional view looking down a
pipe 502 in which the acoustic brake system 102 has generated a
standing wave, in accordance with example embodiments of the
present disclosure. The acoustic brake system 102 of FIG. 5 is
configured to generate an acoustic waveform having five nodes 204,
forming concentric circles in the pipe 502. FIG. 5 shows that the
particulates 210 are concentrated at the five nodes 204 and away
from the wall of the pipe 504.
[0028] FIG. 6 illustrates an example configuration 600 of an
acoustic brake system 602, in which the acoustic brake system 602
includes multiple transducers 606 formed as rings around a pipe
604. In certain example embodiments, the transducers 606 are set at
the same resonant frequency, and particulates in the fluid flowing
through the pipe travel along the one or more nodes of the
generated standing wave and away from the walls of the pipe 604.
The transducer rings 606 can be of any size and there can be any
number of rings. In certain example embodiments, the transducer
rings 606 have a gap or disconnect in the ring 606. This space
allows the transducer material to expand under high temperature
conditions.
[0029] FIG. 7 illustrates another example embodiment 700 of an
acoustic brake system 702, in which the acoustic brake system 702
includes a transducer strip 706 disposed along a length of a
segment of pipe 704. In certain example embodiments, the acoustic
brake system 702 includes a plurality of transducer strips 706
disposed along the length of pipe 704. The transducer strips 706
can be of any size and disposed on the pipe 704 in any
configuration.
[0030] FIG. 8 illustrates another example configuration 600 of an
acoustic brake system 802, in which the acoustic brake system 802
includes a first transducer sheet 806a and a second transducer
sheet 806b disposed around a pipe 804. In certain example
embodiments, the first transducer sheet 806a is disposed on a first
side of a segment of the pipe 804 and a second transducer sheet is
disposed on a second side of the segment of the pipe 804. The
transducer sheets 806 can be of any size and shape and cover all or
a portion of the segment of pipe 804
[0031] An acoustic brake system 102 can have one or a plurality of
separate transducers 206 disposed about a pipe in any
configuration. Specifically, the transducers 206 can have any
suitable shape, such as a ring, a strip, a spot, a sheet, and the
like. Each transducer 206 in an acoustic brake system 102 can
generate the same or distinct waveforms. The desired pattern or
configuration of nodes 204 within the pipe 202 can be implemented
by configuring the waveforms generated by the transducers 206
through the function generator 212. The transducers 206 are coupled
to and driven by the function generator 212. In certain example
embodiments, the function generator 212 is coupled to the pipe 202
as well or at a nearby location. In certain example embodiments,
the function generator 212 is preprogrammed to generate a specified
signal and waveform. In certain example embodiments, the function
generator 212 is controllable through a wired or wireless
controller, which can set or change the parameters of the signal
generated by the function generator. In certain example
embodiments, the frequency generator is powered by an attached or
remote power source. In certain example embodiments, in order to
reduce heating of the transducer 206, the transducers 206 are
configured to emit in tone-burst mode, swept frequency, or through
amplitude modulation. In certain example embodiments, wetted
transducers, which are in direct contact with the fluid within the
pipe 202 are used. In certain example embodiments, the transducers
202 are disposed inside the pipe 202 rather than outside of the
pipe.
[0032] FIG. 9 illustrates a method 900 of reducing particulate
impact in a pipe, in accordance with example embodiments of the
present disclosure. In certain example embodiments, the method 900
includes coupling an acoustic brake system to an external wall of a
pipe (step 902). In certain example embodiments, the acoustic brake
system includes one or more transducers. In certain example
embodiments, the acoustic brake system also includes a function
generator coupled to the one or more transducers. In certain
example embodiments, the method 900 further includes coupling the
one or more transducers to the external wall of the pipe (step
904). The one or more transducers can have any shape, size, or
configuration that is suitable for the pipe and the desired effect.
The method further includes transmitting a signal from the function
generator to the one or more transducers (step 906). The method
further includes generating a standing wave within the pipe by the
one or more transducers, in which the standing wave includes one or
more nodes (step 908). The method also includes pushing a plurality
of particulates towards the one or more nodes and away from the
walls of the pipe (step 910). In certain example embodiments, the
standing wave creates one or more relatively high and one or more
relatively low pressure regions, in which the relatively low
pressure regions are away from the walls of the pipe. Thus, the
particulates are attracted towards the low pressure regions.
[0033] Although embodiments described herein are made with
reference to example embodiments, it should be appreciated by those
skilled in the art that various modifications are well within the
scope and spirit of this disclosure. Those skilled in the art will
appreciate that the example embodiments described herein are not
limited to any specifically discussed application and that the
embodiments described herein are illustrative and not restrictive.
From the description of the example embodiments, equivalents of the
elements shown therein will suggest themselves to those skilled in
the art, and ways of constructing other embodiments using the
present disclosure will suggest themselves to practitioners of the
art. Therefore, the scope of the example embodiments is not limited
herein.
* * * * *