U.S. patent application number 13/401089 was filed with the patent office on 2013-08-22 for fluid pressure actuator.
This patent application is currently assigned to BAKER HUGHES INCORPORATED. The applicant listed for this patent is Lillian Guo, Bobby J. Salinas, Zhiyue Xu. Invention is credited to Lillian Guo, Bobby J. Salinas, Zhiyue Xu.
Application Number | 20130213032 13/401089 |
Document ID | / |
Family ID | 48981209 |
Filed Date | 2013-08-22 |
United States Patent
Application |
20130213032 |
Kind Code |
A1 |
Xu; Zhiyue ; et al. |
August 22, 2013 |
FLUID PRESSURE ACTUATOR
Abstract
An actuator including an actuation member at least partially
defining a chamber and a fluid generating media disposed in the
chamber. The fluid generating media includes a first
electrochemical composition and a second electrochemical
composition. The first and second electrochemical compositions are
together electrochemically responsive to a first fluid for
generating a second fluid. The actuation member is actuatable via a
pressure of the second fluid. A method of controlling an actuator
is also included.
Inventors: |
Xu; Zhiyue; (Cypress,
TX) ; Salinas; Bobby J.; (Houston, TX) ; Guo;
Lillian; (Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Xu; Zhiyue
Salinas; Bobby J.
Guo; Lillian |
Cypress
Houston
Houston |
TX
TX
TX |
US
US
US |
|
|
Assignee: |
BAKER HUGHES INCORPORATED
Houston
TX
|
Family ID: |
48981209 |
Appl. No.: |
13/401089 |
Filed: |
February 21, 2012 |
Current U.S.
Class: |
60/527 |
Current CPC
Class: |
E21B 41/00 20130101 |
Class at
Publication: |
60/527 |
International
Class: |
F01B 29/10 20060101
F01B029/10 |
Claims
1. An actuator comprising: an actuation member at least partially
defining a chamber; and a fluid generating media disposed in the
chamber and including a first electrochemical composition and a
second electrochemical composition, the first and second
electrochemical compositions together being electrochemically
responsive to a first fluid for generating a second fluid, wherein
the actuation member is actuatable via a pressure of the second
fluid.
2. The actuator of claim 1, wherein the media comprises a
controlled electrolytic metallic material.
3. The actuator of claim 1 wherein the media comprises a plurality
of powder particles, the first electrochemical composition
comprises a plurality of particle cores and the second
electrochemical composition comprises a plurality of coating
layers, and each powder particle includes one of the particle cores
and one of the coating layers disposed on the particle core.
4. The actuator of claim 3, wherein the particle cores and the
coating layers are each metallic materials, and the particle cores
have an oxidation potential more negative than that of the coating
layers.
5. The actuator of claim 3, wherein the particle cores comprise Mg,
Al, Zn, Mn, or a combination including at least one of the
foregoing.
6. The actuator of claim 3, wherein the coating layers comprise Al,
Zn, Fe, W, Co, Ni, or a combination including at least one of the
foregoing.
7. The actuator of claim 3, wherein the particle cores have a
diameter of about 5 nm to about 300 nm.
8. The actuator of claim 3, wherein the coating layers have a
thickness of about 25 nm to about 2500 nm.
9. The actuator of claim 1, wherein the first electrochemical
composition comprises a plurality of first powder particles, and
the second composition comprises a plurality of second powder
particles, the first and second powder particles comprising
different electrochemical materials.
10. The actuator of claim 1, further comprising one or more ports
into the chamber.
11. The actuator of claim 10, wherein a check valve is disposed
each of the one or more ports for maintaining the pressure in the
chamber in order to actuate the actuation member.
12. The actuator of claim 10, further comprising a mechanism for
selectively opening the one or more ports.
13. The actuator of claim 12, wherein the mechanism is a plug that
is removable upon exposure to the first fluid.
14. The actuator of claim 13, wherein the plug is a timer or fuse
used to control a timing of actuation of the actuator.
15. The actuator of claim 13, wherein the plug comprises a
controlled electrolytic metallic material.
16. The actuator of claim 1, wherein the actuation member is a
piston.
17. The actuator of claim 1, wherein the first fluid is a downhole
fluid.
18. The actuator of claim 1, wherein the first fluid includes
brine, acid, or a combination including at least one of the
foregoing.
19. The actuator of claim 1, wherein the second fluid is a gas.
20. The actuator of claim 1, wherein the second fluid is
hydrogen.
21. A method of controlling an actuator comprising: exposing a
fluid generating media to a first fluid, the media including a
first electrochemical component and a second electrochemical
component; reacting the first and second electrochemical components
electrochemically together upon exposure to the first fluid for
generating a second fluid with the media; and actuating an
actuation member of the actuator with a pressure of the second
fluid.
22. The method of claim 21 further comprising setting a volume, a
composition, or a combination including at least one of the
foregoing of the fluid generating media for controlling an
actuation speed, an actuation magnitude, or a combination including
at least one of the foregoing of the actuator upon exposure of the
fluid generating media to the first fluid.
Description
BACKGROUND
[0001] Fluid pressure is utilized for powering actuators in a
variety of industries. For example, fluid pressure is used
ubiquitously in the downhole drilling and completions industry to
shift sleeves, open and close valves, move tubulars, drive pistons,
set seals, etc. Currently fluid pressure for downhole operational
use is provided by pumping fluid downhole from surface. To this
end, specific setting tools and pipeline are often required to be
installed and a significant amount of fluid must be pumped
downhole, as the entire length of the pipeline to the downhole
location must be filled with the pressurized fluid. Due to the wide
range of possible uses and the foregoing limitations in current
systems, alternate systems for enabling timely, accurate, reliable,
and controllable fluid pressure actuation are always well
received.
SUMMARY
[0002] An actuator including an actuation member at least partially
defining a chamber; and a fluid generating media disposed in the
chamber and including a first electrochemical composition and a
second electrochemical composition, the first and second
electrochemical compositions together being electrochemically
responsive to a first fluid for generating a second fluid, wherein
the actuation member is actuatable via a pressure of the second
fluid.
[0003] A method of controlling an actuator including exposing a
fluid generating media to a first fluid, the media including a
first electrochemical component and a second electrochemical
component; reacting the first and second electrochemical components
electrochemically together upon exposure to the first fluid for
generating a second fluid with the media; and actuating an
actuation member of the actuator with a pressure of the second
fluid.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] The following descriptions should not be considered limiting
in any way. With reference to the accompanying drawings, like
elements are numbered alike:
[0005] FIG. 1 is a schematic cross-sectional view of an actuator
controlled by exposing a fluid generating media to a fluid;
[0006] FIG. 2 is a photomicrograph of a powder 110 as disclosed
herein that has been embedded in an epoxy specimen mounting
material and sectioned;
[0007] FIG. 3 is a schematic illustration of an exemplary
embodiment of a powder particle 112 as it would appear in an
exemplary section view represented by section 3-3 of FIG. 2;
and
[0008] FIG. 4 is a schematic illustration of a second exemplary
embodiment of a powder particle 112 as it would appear in a second
exemplary section view represented by section 3-3 of FIG. 2.
DETAILED DESCRIPTION
[0009] A detailed description of one or more embodiments of the
disclosed apparatus and method are presented herein by way of
exemplification and not limitation with reference to the
Figures.
[0010] Referring now to FIG. 1, a fluid pressure actuator 10 is
illustrated having a piston 12 arranged in a housing 14 for
performing some desired operation. In various embodiments the
piston 12 could be arranged to shift a component, open or close a
port or valve, activate or deactivate a tool, set a seal, pump a
fluid, etc. It is also to be appreciated that other components
could be substituted for the piston 12, and the piston 12 is given
as one example only. For example, the piston 12 could be replaced
by any combination of sleeves, plugs, rings, arms, levers,
inflatables, or any other component which is activated, triggered,
driven, influenced, controlled, or otherwise actuated by fluid
pressure. Additionally, although the piston 12 is arranged to move
axially, actuation with respect to any other direction, such as
rotationally, radially, etc., is also accomplishable. Moreover, the
pressure could be used not to move a component, but instead to
dampen or prevent movement of a component, and these uses are to be
understood as included in the meaning of the term "actuate" (or any
form thereof), as used herein. For ease of discussion, the actuator
10 may be discussed herein as being installed in a downhole
environment, although it is to be appreciated that the actuator 10
could have use in any other industry or application in which the
generation of a fluid (e.g., hydrogen gas, as discussed below)
and/or use of a resulting pressure of the generated fluid is
desired.
[0011] A piston chamber 16 is located on one side of the piston 12
and filled with a fluid generating media 18. The fluid generating
media 18 is selected as a material that is responsive to a fluid
20. By responsive it is meant that the media 18 will react,
corrode, dissolve, disintegrate, degrade, or otherwise be consumed
or removed due to exposure to the fluid 20, and as a result of
chemical reactions between the fluid 20 and the media 18, produce
additional fluid in the chamber 16. For example, in one embodiment
the fluid 20 is a downhole aqueous fluid mixture and the media 18
comprises both electrochemically active metals having high standard
oxidation potentials, e.g., Mg, Zn, Al, Mn, etc., and less
electrochemically active metals, such as Ni, Fe, W, Co, etc. that
are together electrochemically reactive in the presence of the
fluid 20 for generating an actuation fluid. More particularly, and
as is discussed in more detail below, the media 18 can take the
form of controlled electrolytic metallic materials, which are
highly tailorable to different rates of reaction (i.e., corrosion)
depending on the particular compositions and materials used to form
the material. It is to be appreciated that the fluid 20 can take
the form of any combination of naturally present downhole fluids
and those that are purposefully delivered or pumped to the actuator
10.
[0012] The fluid 20 is initially isolated from the media 18, e.g.,
via a fluid barrier or wall 22. The wall 22 fluidly seals the
chamber 16 from the fluid 20 with the exception of a port 24
therein (or multiple ones of the port 24). Flow through the port 24
may be initially blocked, e.g., by a mechanism 26. The mechanism 26
is intended to temporarily prevent flow of the fluid 20 through the
port 24 until some amount of time passes or event occurs, and can
take various forms to this end, e.g., a timer, delay, fuse, etc.
For example, in the illustrated embodiment the mechanism 26 takes
the form of a plug 28 that, like the media 18, is responsive to the
fluid 20 and will be removed by the fluid 20 after being exposed to
it for some amount of time. For example, a plug made from a
controlled electrolytic metallic material could be inserted into
the port 24 and removed at a predictable rate by exposure to the
fluid 20, based on a known or estimated composition of the fluid 20
and a tailored composition of the plug 28. In other embodiments,
the plug 28 could be removed physically instead of chemically, the
wall 22 could be provided with or as a movable mechanism for
selectively blocking the port 24 and rotating, sliding, etc. to
open the port, etc. The mechanism 26 could also include a clock or
countdown timer that enables activation of such a movable mechanism
after some amount of time. Additionally or alternatively, the
mechanism 26 could include a sensor that actuates a movable
mechanism after detection of a certain downhole condition,
parameter, or value thereof (e.g., temperature, pressure, sound,
etc.).
[0013] A check valve 30 is arranged in the port 24 of the
illustrated embodiment for enabling the fluid 20 to flow into the
chamber 16 after the mechanism 26 has been triggered (e.g.,
removed) to open the port 24. As noted above, the media 18 will
generate an actuation fluid (e.g., hydrogen gas) upon exposure to
the fluid 20, and the check valve 30 will also prevent the
generated fluid from escaping the chamber 16 in order to maintain
pressure in the chamber 16 for actuating the piston 12.
[0014] As noted above, in one embodiment the fluid to be generated
by the media 18 is a gas, more specifically, hydrogen gas. Hydrogen
gas is convenient in downhole use because it results from the
exposure of many reactive metals, e.g., magnesium, aluminum, zinc,
etc. to various downhole fluids. Although these metals are
relatively highly reactive, the rate of hydrogen or other fluid
generation upon contact with downhole fluids is too slow for many
downhole actuation applications. Methods of creating materials with
increased rates of dissolution or corrosion, and therefore fluid
generation, particularly hydrogen generation, are taught by United
States Patent Publication No. 2011/0135953 (Xu), which Publication
is hereby incorporated by reference in its entirety. As discussed
in the Xu publication, by forming particles having an
electrochemically reactive nano-coating and an electrochemically
reactive core, the rate of corrosion of the selected materials can
be increased by literally hundreds of times, or tailored to any
desired level therebelow. By increasing the rate of corrosion,
e.g., by magnesium and similarly highly reactive metals, the rate
of fluid generation, e.g., hydrogen generation, is correspondingly
increased and therefore suitable for actuating the piston 12 of the
actuator 10 or some other actuation member.
[0015] In one embodiment, the media 18 takes the form of a powder,
e.g., a powder 110 in FIGS. 2-4, or a sintered compact made from
the powder (further examples provided by the Xu publication
incorporated above by reference). Referring to FIGS. 2-4, the
powder 110 includes a plurality of metallic, coated powder
particles 112. Each of the metallic, coated powder particles 112 of
the powder 110 includes a particle core 114 and a metallic coating
layer 116 disposed on the particle core 114. The particle core 114
includes a core material 118. The core material 118 may include any
suitable material for forming the particle core 114 that provides
an electrochemical reaction with a material 120 of the metallic
coating layer 116, e.g., when exposed to brine or other suitable
fluid. Suitable core materials 118 include electrochemically active
metals having a standard oxidation potential about greater than or
equal to that of Zn, including as Mg, Al, Mn or Zn or a combination
thereof. As noted above, these electrochemically active metals are
very reactive with a number of common wellbore fluids, including
any number of ionic fluids or highly polar fluids, such as those
that contain various chlorides. Examples include fluids comprising
potassium chloride (KCl), hydrochloric acid (HCl), calcium chloride
(CaCl2), calcium bromide (CaBr2) or zinc bromide (ZnBr2). For
example, electrochemical reactions, e.g., galvanic or electrolytic
corrosion, in the presence of brine, e.g., including KCl or other
salts dissolved in an aqueous solution (KCl being typically present
downhole in an approximately 3% concentration), will produce
hydrogen gas. The electrochemical reactions may be accompanied by
other fluid generating processes, such as by dissolving the
reactive metals with acids, e.g., HCl. The core material 118 may
also include other metals that are less electrochemically active
than Zn or non-metallic conductive materials, such as graphite. The
material 120 could be other electrochemically reactive metals
having electrochemical potentials more positive than that of the
core material 118.
[0016] In an exemplary embodiment of the powder 110, the particle
core 114 includes Mg, Al, Mn or Zn, or a combination thereof, as
the core material 118, and more particularly may include pure Mg
and Mg alloys, and the metallic coating layer 116 includes Al, Zn,
Mn, Mg, Mo, W, Cu, Fe, Si, Ca, Co, Ta, Re, or Ni, or an oxide,
nitride or a carbide thereof, or a combination of any of the
aforementioned materials as the coating material 120. Of course,
the core material 118 could be alternatively selected as less
active, with the material 120 having a more electrochemically
negative potential. The core material 118 for the particles 112 in
the media 18 could all be the same material, or a combination of
different materials, and similarly, the material 120 of the coating
layers 116 could all be the same material, or a combination of
different materials, with electrochemical reactions occurring
between particles of different compositions and/or between cores
and coatings of different compositions but of the same
particle.
[0017] With regard to the electrochemically active materials, these
materials may be used as pure metals or in any combination with one
another, including various alloy combinations of these materials,
including binary, tertiary, or quaternary alloys of these
materials. These combinations may also include composites of these
materials. Further, in addition to combinations with one another,
Mg, Al, Mn, Zn or other core materials 118 may also include other
constituents, including various alloying additions, to alter one or
more properties of the particle cores 114, such as by lowering the
density or altering the dissolution characteristics of the core
material 118. In an exemplary embodiment, the core material 118
will be selected to provide a core chemical composition and the
coating material 120 will be selected to provide a coating chemical
composition and these chemical compositions will also be selected
to differ from one another. Differences in the chemical
compositions of the coating material 120 and the core material 118
may be selected to provide different dissolution rates and
selectable and controllable dissolution of the media 18 formed
therefrom, making the media 18 selectably and controllably
dissolvable.
[0018] Among the electrochemically active materials, Mg, either as
a pure metal or an alloy or a composite material, is particularly
useful, because of its high degree of electrochemical activity,
since it has a standard oxidation potential higher than Al, Mn or
Zn. Mg alloys include all alloys that have Mg as an alloy
constituent. Mg alloys that combine other electrochemically active
metals, as described herein, as alloy constituents are particularly
useful, including binary Mg--Zn, Mg--Al and Mg--Mn alloys, as well
as tertiary Mg--Zn--Y and Mg--Al--X alloys, where X includes Zn,
Mn, Si, Ca or Y, or a combination thereof. These Mg--Al--X alloys
may include, by weight, up to about 85% Mg, up to about 15% Al and
up to about 5% X. The electrochemically active metals including Mg,
Al, Mn or Zn, or combinations thereof, may also include a rare
earth element or combination of rare earth elements. As used
herein, rare earth elements include Sc, Y, La, Ce, Pr, Nd or Er, or
a combination of rare earth elements. Where present, a rare earth
element or combinations of rare earth elements may be present, by
weight, in an amount of about 5% or less.
[0019] The particle cores 114 may have any suitable particle size
or range of particle sizes or distribution of particle sizes. For
example, the particle cores 114 may be selected to provide an
average particle size that is represented by a normal or Gaussian
type unimodal distribution around an average or mean. In another
example, the particle cores 114 may be selected or mixed to provide
a multimodal distribution of particle sizes, including a plurality
of average particle core sizes, such as, for example, a homogeneous
bimodal distribution of average particle sizes (as discussed more
detail in the Xu publication, incorporated by reference above). The
selection of the distribution of particle core size may be used to
determine, for example, the particle size and an interparticle
spacing 115 of the particles 112 of the powder 110. In an exemplary
embodiment, the particle cores 114 may have a unimodal distribution
and an average particle diameter of about 5 .mu.m to about 300
.mu.m, more particularly about 80 .mu.m to about 120 .mu.m, and
even more particularly about 100 .mu.m.
[0020] The particle cores 114 may have any suitable particle shape,
including any regular or irregular geometric shape, or combination
thereof. In an exemplary embodiment, the particle cores 114 are
substantially spheroidal electrochemically active metal particles.
In another exemplary embodiment, the particle cores 114 are
substantially irregularly shaped ceramic particles.
[0021] The metallic coating layer 116 is a nanoscale coating layer
for the particle cores 114. In an exemplary embodiment, the
metallic coating layer 116 may have a thickness of about 25 nm to
about 2500 nm. The thickness of the metallic coating layer 116 may
vary over the surface of the particle core 114, but will preferably
have a substantially uniform thickness over the surface of the
particle core 114. The metallic coating layer 116 may include a
single layer, as illustrated in FIG. 3, or a plurality of layers as
a multilayer coating structure, as illustrated in FIG. 4. That is,
the coating layer 116 in FIG. 4 includes two layers as the core
material 120, with a first layer 122 disposed on the surface of the
particle core 114 and a second layer 124 disposed on the surface of
the first layer 122. The first layer 122 has a chemical composition
that is different than the chemical composition of the second layer
124 for enabling further tailoring of the properties of the powder
110, e.g., different rates of dissolution of the media 18. In a
single layer coating, or in each of the layers of a multilayer
coating, the metallic coating layer 116 may include a single
constituent chemical element or compound, or may include a
plurality of chemical elements or compounds. Where a layer includes
a plurality of chemical constituents or compounds, they may have
all manner of homogeneous or heterogeneous distributions, including
a homogeneous or heterogeneous distribution of metallurgical
phases. This may include a graded distribution where the relative
amounts of the chemical constituents or compounds vary according to
respective constituent profiles across the thickness of the layer.
In both single layer and multilayer coatings 116, each of the
respective layers, or combinations of them, may be used to provide
a predetermined property to the powder particle 112 or a sintered
powder compact formed therefrom. For example, the predetermined
property may include the bond strength of the metallurgical bond
between the particle core 114 and the coating material 120; the
interdiffusion characteristics between the particle core 114 and
the metallic coating layer 116, including any interdiffusion
between the layers of a multilayer coating layer 116; the
interdiffusion characteristics between the various layers of a
multilayer coating layer 116; the interdiffusion characteristics
between the metallic coating layer 116 of one powder particle and
that of an adjacent powder particle 112; the bond strength of the
metallurgical bond between the metallic coating layers of adjacent
sintered powder particles 112, including the outermost layers of
multilayer coating layers; and the electrochemical activity of the
coating layer 116.
[0022] It is to be appreciated that any number of layers may be
included in various embodiments according to the current invention
(as further discussed in the Xu publication incorporated by
reference above). The thickness of the various layers in
multi-layer configurations may be apportioned between the various
layers in any manner so long as the sum of the layer thicknesses
provide a nanoscale coating layer 116, including layer thicknesses
as described herein. In one embodiment, the first layer 122 and
outer layer (e.g., the layer 124 or some other layer depending on
the number of layers) may be thicker than other layers, where
present, due to the desire to provide sufficient material to
promote the desired bonding of the first layer 122 with the
particle core 114, or the bonding of the outer layers of adjacent
powder particles 112, e.g., during sintering of a powder compact
from the powder 110, or to further tailor the rate of dissolution
of the powder 110 and therefore generation of a fluid by the media
18 upon contact with the fluid 20.
[0023] In view of the foregoing, it is to be appreciated that the
timing, speed, and magnitude (force and/or distance) of actuation
can be controlled by controlling the volume, surface area,
composition, etc., of the media 18. As noted above, the timing of
the reaction can be triggered by use of the mechanism 26 or some
other timer, delay, clock, sensor, fuse, etc.
[0024] The speed of fluid generation by the media 18 can be
increased by increasing the surface area of the media 18. That is,
for example, forming the media 18 as powder, e.g., the powder 110,
will generally increase the speed by which fluid is generated as
there is more surface area to react with the fluid 20. Similarly,
the media 18 can be formed as sintered or formed beads, pellets, or
the like, if a moderate degree of speed is required, or as a
single, relatively large compact if the speed of actuation is
desired to be slower.
[0025] Furthermore, with knowledge of the chemical composition of
the fluid 20, the initial volume of the chamber 16 and/or surface
area of the piston 12 in the chamber 16, and a desired volume of
the chamber 16 after actuation and/or desired actuation force to be
exerted on the piston 12 and/or desired actuation distance for the
piston 12 to travel, a volume and composition of the media 18 for
generating a suitable amount of fluid can be calculated. For
example, if hydrogen is desired to be produced, and it is known
that the downhole fluids are a KCl brine (typically of about 3%
concentration of KCl), then the known chemical reactions of the
materials comprising the media 18, e.g., a controlled electrolytic
metallic material including magnesium and other highly reactive
metals, can be used to determining the proper amount of the media
18 to use given a desired amount of hydrogen generation desired. In
this example, hydrogen generation will result from both the
chemical reaction of magnesium (or other reactive metal) being
exposed to water and the galvanic couplings formed between the
differing electrochemical components of the media 18, e.g., the
particle cores and coating layers of a controlled electrolytic
material as discussed above, and will be governed by the following
reactions: 2 H.sup.++2 e.fwdarw.H.sub.2 (cathodic partial
reaction); 2 Mg.fwdarw.2 Mg.sup.++e (anodic partial reaction); 2
Mg.sup.2++2 H.sub.2O.fwdarw.2 Mg.sup.2++2 OH.sup.-+H.sub.2
(chemical reaction); 2 Mg+2H.sup.++2 H.sub.2O.fwdarw.2 Mg.sup.2++2
OH.sup.-+2 H.sub.2 (overall reaction); and 2 Mg.sup.2++2
OH.fwdarw.Mg (OH).sub.2 (product formation). The rate of hydrogen
or other fluid generation may be increased or tailored by the
presence of other chemical components or catalysts, such as acids,
the combination and concentrations of materials forming the
galvanic couplings, etc. In one embodiment hydrochloric acid (HCl)
is included in the fluid 20, and hydrogen generation is further
defined by the reaction: 2 Mg+2 HCl.fwdarw.2 MgCl+H.sub.2. With
respect to Mg, it has been found that including other elements,
e.g., Fe, Ni, Cu, Co, etc., in a controlled electrolytic material,
that the rate of corrosion of Mg, and therefore rate of production
of hydrogen, can be increased significantly when the other element
is present in as low of a concentration as 0.2% with respect to
that of Mg. Of course, Mg, KCl, and HCl are given as examples only,
and other materials, chemicals, concentrations, compositions,
combinations, etc. for the media 18 and the fluid 20, could be
utilized and behave according to other known reactions. According
to these known chemical and electrochemical reactions for the
various materials discussed herein for the media 18 and the fluid
20, the speed of the generation of hydrogen or other fluid can be
tailored and the proper amount of the media 18 determined with
respect to its composition and the composition of the fluid 20 for
accurately, timely, and reliably actuating a tool, device,
mechanism, etc., as discussed herein.
[0026] While the invention has been described with reference to an
exemplary embodiment or embodiments, it will be understood by those
skilled in the art that various changes may be made and equivalents
may be substituted for elements thereof without departing from the
scope of the invention. In addition, many modifications may be made
to adapt a particular situation or material to the teachings of the
invention without departing from the essential scope thereof.
Therefore, it is intended that the invention not be limited to the
particular embodiment disclosed as the best mode contemplated for
carrying out this invention, but that the invention will include
all embodiments falling within the scope of the claims. Also, in
the drawings and the description, there have been disclosed
exemplary embodiments of the invention and, although specific terms
may have been employed, they are unless otherwise stated used in a
generic and descriptive sense only and not for purposes of
limitation, the scope of the invention therefore not being so
limited. Moreover, the use of the terms first, second, etc. do not
denote any order or importance, but rather the terms first, second,
etc. are used to distinguish one element from another. Furthermore,
the use of the terms a, an, etc. do not denote a limitation of
quantity, but rather denote the presence of at least one of the
referenced item.
* * * * *