U.S. patent application number 10/046823 was filed with the patent office on 2003-07-17 for alkyl-substituted aryl polyalkoxylates and their use in fuels.
This patent application is currently assigned to Ethyl Corporation. Invention is credited to Colucci, William J., Jao, Tze Chi, Li, Shoutian.
Application Number | 20030131527 10/046823 |
Document ID | / |
Family ID | 21945585 |
Filed Date | 2003-07-17 |
United States Patent
Application |
20030131527 |
Kind Code |
A1 |
Colucci, William J. ; et
al. |
July 17, 2003 |
Alkyl-substituted aryl polyalkoxylates and their use in fuels
Abstract
The present invention relates to an alkyl-substituted aryl
polyalkoxylate composition, fuel concentrates, and fuel
compositions containing the composition. The invention further
relates to the use of the alkyl-substituted aryl polyalkoxylate
composition in fuel combusted in engines to reduce the formation of
intake valve deposits and to reduce valve sticking in the
engines.
Inventors: |
Colucci, William J.; (Glen
Allen, VA) ; Li, Shoutian; (Midlothian, VA) ;
Jao, Tze Chi; (Glen Allen, VA) |
Correspondence
Address: |
FITCH EVEN TABIN AND FLANNERY
120 SOUTH LA SALLE STREET
SUITE 1600
CHICAGO
IL
60603-3406
US
|
Assignee: |
Ethyl Corporation
|
Family ID: |
21945585 |
Appl. No.: |
10/046823 |
Filed: |
January 17, 2002 |
Current U.S.
Class: |
44/447 |
Current CPC
Class: |
C10L 1/1985 20130101;
C10L 1/143 20130101; C10L 1/2383 20130101; C10L 1/305 20130101;
C10L 1/2387 20130101; C10L 1/1881 20130101; C10L 1/223 20130101;
C08G 65/2612 20130101; C10L 10/04 20130101; C10L 1/1832 20130101;
C10L 1/1905 20130101; C10L 1/238 20130101; C10L 1/2437
20130101 |
Class at
Publication: |
44/447 |
International
Class: |
C10L 001/18 |
Claims
What is claimed:
1. A alkyl-substituted aryl polyalkoxylate of the formula
R--(Ar).sub.n--(O-A).sub.m--OH where R is a polyalkene radical
derived from C.sub.2- to C.sub.20-alkenes and having a number
average molecular weight of from about 200 to about 5,000; Ar is
selected from a phenylene group, a substituted phenylene group, and
a polynuclear aromatic group; A is an alkylene group of 2 to 8
carbon atoms; m is a number up to 200; and n is or 2.
2. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which R is a polybutyl or polyisobutyl radical derived from
isobutene and up to about 20 percent by weight of n-butene and
having a number average molecular weight of from about 200 to about
2500.
3. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which R is a polybutyl or polyisobutyl radical having a number
average molecular weight of from about 400 to about 1250.
4. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which R is a polybutyl or polyisobutyl radical having a number
average molecular weight of from about 450 to about 1000.
5. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which m is a number up to about 45.
6. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which A is 1,2-propylene and/or 1,2-butylene.
7. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which Ar is a phenol.
8. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which Ar is a hydrocarbon-substituted phenol.
9. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which Ar is a cresol.
10. An alkyl-substituted aryl polyalkoxylate as claimed in claim 1,
in which Ar is a hydrocarbon-substituted cresol.
11. A fuel additive concentrate comprising an alkyl-substituted
aryl polyalkoxylate of claim 1 in an amount of from about 0.1 to
about 80% by weight.
12. A fuel additive concentrate comprising an alkyl-substituted
aryl polyalkoxylate of claim 1 in an amount of from about 0.5 to
about 60% by weight.
13. A fuel composition comprising an alkyl-substituted aryl
polyalkoxylate of claim 1, and a fuel.
14. The composition of claim 13, wherein the fuel is gasoline.
15. The composition of claim 13, wherein the fuel is diesel
fuel.
16. The composition of claim 13, wherein the fuel is burner
fuel.
17. The composition of claim 13, wherein the fuel is jet fuel.
18. A process for reducing the formation of intake valve deposits
in a gasoline engine, comprising combusting in a gasoline engine
having intake valves a fuel composition comprising a gasoline fuel
and an alkyl-substituted aryl polyalkoxylate of the formula
R--(Ar).sub.n--(O-A).sub.m--OH where R is a polyalkene radical
derived from C.sub.2- to C.sub.20-alkenes and having a number
average molecular weight of from about 200 to about 5,000; Ar is
selected from a phenylene group, a substituted phenylene group, and
a polynuclear aromatic group; A is an alkylene group of 2 to 8
carbon atoms; m is a number up to 200; and n is 1 or 2, whereby the
amount of deposits formed on the intake valves are reduced relative
to the amount of deposits formed on the intake valves when the fuel
composition combusted in the engine does not comprise the
alkyl-substituted aryl polyalkoxylate.
19. A process for reducing the valve sticking in a gasoline engine,
comprising combusting in a gasoline engine having intake valves a
fuel composition comprising a gasoline fuel and an
alkyl-substituted aryl polyalkoxylate of the formula
R--(Ar).sub.n--(O-A).sub.m--OH where R is a polyalkene radical
derived from C.sub.2- to C.sub.20-alkenes and having a number
average molecular weight of from about 200 to about 5,000; Ar is
selected from a phenylene group, a substituted phenylene group, and
a polynuclear aromatic group; A is an alkylene group of 2 to 8
carbon atoms; m is a number up to 200; and n is 1 or2, whereby the
amount of sticking of the intake valves is reduced relative to the
amount of sticking of the intake valves when the fuel composition
combusted in the engine does not comprise the alkyl-substituted
aryl polyalkoxylate.
20. The composition of claim 13, further comprising a
detergent.
21. The composition of claim 20, wherein the detergent is selected
from polyisobuteneamines, hydroxyl-containing polyisobuteneamines,
polyetheramines, and polyalkenyl Mannich bases.
22. The composition of claim 20, wherein the detergent is a
polyalkenyl Mannich base.
23. The composition of claim 20, further comprising one or more
components selected from alkali metal salts of carboxylic acids or
esters, alkaline earth metal salts of carboxylic acids or esters,
alkali metal salts of sulfosuccinic acids or esters, alkaline earth
metal salts of sulfosuccinic acids or esters, diluents, corrosion
inhibitors, film-forming ammonium salts of organic carboxylic acids
or esters, heterocyclic aromatics, antioxidants, stabilizers,
demulsifiers, antistatic agents, metaliocenes, lubricity additives,
and markers.
Description
TECHNICAL FIELD
[0001] The present invention relates to special alkyl-substituted
aryl polyalkoxylates, their use as carrier oils, as detergents in
fuel compositions, and fuel additive concentrates, and fuel
compositions that contain these alkyl-substituted aryl
polyalkoxylates.
BACKGROUND INFORMATION
[0002] Carburetors and intake systems of gasoline engines as well
as injection systems for fuel metering are increasingly being
contaminated by dust particles from the air, uncombusted
hydrocarbon residues from the combustion chamber, and the crank
case vent gases passed into the carburetor.
[0003] To avoid these disadvantages, additives (detergents) are
added to the fuel to keep valves and carburetor or injection
systems clean. Such detergents are generally used in combination
with one or more carrier oils. The carrier oils perform an
additional wash function, often support and promote the detergents
in their cleaning and keeping clean effect and can thus help to
reduce the amount of detergents required. The carrier oils usually
used are viscous, high-boiling and in particular heat-stable
liquids. They coat the hot metal surfaces, for example the intake
valves, with a thin liquid film and thus prevent or delay the
formation and deposition of decomposition products on the metal
surfaces.
[0004] Frequently used carrier oils are, for example, high-boiling
refined mineral oil fractions, but also synthetic liquids, such as
oil-soluble adducts of alkylene oxides with alcohols. EP-A 277345
describes adducts of ethylene oxide, propylene oxide and/or
butylene oxide with polybutyl or polyisobutene alcohols as carrier
oils in fuel or lubricant compositions, it being possible for from
1 to 200 such alkylene oxide units to undergo addition per mole of
alcohol, but the molecular weight of the polyisobutene should not
be exceeded.
[0005] WO 00/50543 teaches a polyalkene alcohol polyalkoxylate for
use in fuel compositions. No mention is made in WO 00/50543 of an
alkyl-substituted aryl poly alkoxylate composition for fuels.
[0006] However, the carrier oils known from the prior art
frequently have only limited compatibility with other additives, so
that separation may occur. Furthermore, the generally high
viscosity of these carrier oils often gives rise to formulation
problems. In particular, they are not yet capable of completely
eliminating the undesired effect of "sticking of the valves".
"Sticking of the valves" is understood as meaning complete loss of
compression on one or more cylinders of the internal combustion
engine it owing to polymer deposits on the valve shaft, the spring
force is no longer sufficient to close the valves properly.
SUMMARY OF THE INVENTION
[0007] It is an object of the present invention to provide carrier
oils for detergents in fuel compositions, which carrier oils no
longer have the prior art problems described. In particular, these
carrier oils should, as far as possible, be additionally effective
as detergents.
[0008] The present invention achieves this object by adding to a
fuel an alkyl-substituted aryl polyalkoxylates of the formula I
R--(Ar).sub.n--(O-A).sub.m--OH (I)
[0009] where
[0010] R is a polyalkene radical derived from C.sub.2- to
C.sub.20-alkenes and having a number average molecular weight of
from about 200 to about 5,000,
[0011] Ar is a phenylene group, substituted phenylene group, or a
polynuclear aromatic group,
[0012] A is an alkylene group of 2 to 8 carbon atoms,
[0013] m is a number up to 200, and
[0014] n is 1 or 2.
[0015] By "aryl" herein is meant phenylene, substituted phenylene,
such as cresol, and polynuclear compounds.
[0016] Suitable radicals R are straight-chain or branched
hydrocarbon groups, saturated or partially unsaturated, which are
derived from C.sub.2- to C.sub.20-alkenes, in particular from
C.sub.3- to C.sub.12-alkenes, especially from C.sub.3- to
C.sub.6-alkenes. Examples of typical alkenes are ethene, propene,
butenes, pentenes, hexenes, heptenes, octenes, nonenes, decenes,
undecenes, and dodecenes. Of particular interest are propene,
n-butene, and isobutene. The polyalkene on which the hydrocarbon
radical R is based is obtainable by oligomerization or
polymerization of these alkenes, the oligomerization or
polymerization being carried out as a rule (for example by cationic
or coordinate oligomerization or polymerization) to produce at
least one double bond which can be further reacted with the Ar
group to give the corresponding aryl polyalkoxylate.
[0017] R is preferably a polybutyl or polyisobutyl radical derived
from butylene or isobutene and up to 20% by weight of n-butene and
preferably having a number average molecular weight (MN) of from
200 to 2500. R more preferably is a polybutyl or polyisobutyl
radical having a number average molecular weight of from about 350
to about 1500, in particular from about 400 to about 1250,
especially from about 450 to about 1000. Preferably, in an
embodiment of the present invention, R is also composed solely of
isobutene units.
[0018] R may preferably be based on highly reactive polyisobutene
(having double bonds predominantly in the alpha position) which, as
described in EP-A 277345. The aromatic linking group Ar is
preferably a phenylene group, or a substituted phenylene group,
such as a cresol group, or a polynuclear aromatic group, or a
substituted polynuclear aromatic group. Examples of some preferred
Ar groups herein can include phenylene, and alkyl-substituted
phenylene. More preferred in the present invention is where the Ar
group is phenylene or methyl phenylene. The Ar group can have
substituents including hydrocarbyl substituents, such as but not
limited to, alkyl and alkenyl straight chain and branched
hydrocarbon substituents. It is particularly surprising that the
aromatic linking group can impart improved intake valve deposit
performance to detergent fuel formulations containing a component
having this group. It is also surprising to achieve improved valve
stick performance in an engine combusting a fuel composition
containing this aromatic linking group in the additive of the
present invention.
[0019] The alkylene group A is preferably derived from
corresponding alkylene oxides, such as ethylene oxide, propylene
oxide, 1,2-butylene oxide, and cis- or trans-2,3-butylene oxide.
However, it may also be 1,3-propylene, 1,4-butylene, 1,6-hexylene
or 1,8-octylene. A may also comprise a mixture of different groups
from among the stated groups. A can particularly preferably
comprise a 1,2-propylene group, a 1,2-butylene group, or a mixture
thereof, or an ethylene oxide group (EO), a propylene oxide group
(PO), or a mixture thereof (EO/PO). Another preferred A is a
mixture of ethylene oxide groups, propylene oxide groups, and
butylene oxide groups (BO), or (EO/PO/BO). The most preferred A
group is 1,2-propylene group.
[0020] The number m may be a single integer or a combination of
several or many integers, representing wider molecular weight
distributions. The number m may be a number from 1 to about 200. A
preferred range of values for m in an embodiment of the present
invention is between 12 and 32, more preferred is 16-28, and most
preferred is about 24. The number m can represent the sum of
subscripts x, y, and/or z, where x is the subscript in (EO).sub.x,
y is the subscript in (PO).sub.y, and z is the subscript in
(BO).sub.z, where (EO), (PO), and (BO) make up the mixture of
groups in A.
DETAILED DESCRIPTION OF THE INVENTION
[0021] The novel alkyl-substituted aryl polyalkoxylates (I) can be
prepared by conventional methods, for example, by reacting the
parent hydroxy aromatic compound with the corresponding amount of
alkylene oxide in the presence of suitable catalysts, such as
potassium hydroxide, preferably in an amount of from about 0.01 to
1% by weight, particularly from about 0.05 to about 0.5% by weight
of potassium hydroxide, based on the amount of the reaction product
expected. Typical reaction temperatures are from 70 to 200.degree.
C., in particular from about 100 to 160.degree. C. The pressure is
usually from 3 to 30 bar. The reaction product is worked up in the
usual manner by expelling volatile components under reduced
pressure and, if required, by filtration.
[0022] The novel alkyl-substituted aryl polyalkoxylates (I) are
very suitable as carrier oils for detergents in fuel compositions.
They are particularly useful in gasoline fuel compositions, as well
as diesel fuel, heating oil, residual oils, and jet fuels.
[0023] Examples of conventional detergents useful in the present
invention are:
[0024] (a) polyisobuteneamines which are obtainable, according to
EP-A 244616, by hydroformylation of highly reactive polyisobutene
and subsequent reductive amination with ammonia, monoamines or
polyamines, such as dimethyleneaminopropylamine, ethylenediamine,
diethylenetriamine, triethylenetetramine or
tetraethylenepentamine,
[0025] (b) poly(iso)buteneamines which are obtainable by
chlorination of polybutenes or polyisobutenes having double bonds
predominantly in the beta and gamma position, and subsequent
amination with ammonia, monoamines, or the abovementioned
polyamines,
[0026] (c) poly(iso)buteneamines which are obtainable by oxidation
of double bonds in poly(iso)butenes with air or ozone to give
carbonyl or carboxyl compounds and subsequent amination under
reducing (hydrogenating) conditions,
[0027] (d) polyisobuteneamines which are obtainable, according to
DE-A 19620262, from polyisobutene epoxides by reaction with amines
and subsequent dehydration and reduction of the aminoalcohols,
[0028] (e) if required, hydroxyl-containing polyisobuteneamines
which are obtainable, according to WO-A 97/03946, by reaction of
polyisobutenes having an average degree of polymerization of from 5
to 100 with nitrogen oxides or mixtures of nitrogen oxides and
oxygen and subsequent hydrogenation of these reaction products,
[0029] (f) hydroxyl-containing polyisobuteneamines which are
obtainable, according to EP-A 476 485, by reaction of polyisobutene
epoxides with ammonia, monoamines or the abovementioned
polyamines,
[0030] (g) polyetheramines which are obtainable by reaction of
C.sub.2- to C.sub.30-alkanols, C.sub.6- to C.sub.30-alkeanediols
alkanediols, mono- or di-C.sub.2- to C.sub.30-alkylamines, C.sub.1-
to C.sub.30-alkylcyclohexanols or C.sub.1- to C.sub.30-alkylphenols
with from 1 to 30 mol of ethylene oxide and/or propylene oxide
and/or butylene oxide per hydroxyl or amino group and subsequent
reductive amination with ammonia, monoamines, or the abovementioned
polyamines, it also being possible to use polyetheramines having a
carbamate structure,
[0031] (h) polyalkenyl Mannich bases which are obtainable,
according to EP-A 831 141, by reaction of, for example,
polyisobutene-substituted phenols, or polypropylene-substituted
phenols, or polyalphaolefin-substit- uted phenols with aldehydes
and monoamines or the abovementioned polyamines, and
[0032] (i) conventional dispersants, for example, imides, amides,
and esters of polyisobutene succinic anhydrides.
[0033] Further, fuel additives which may be used, together with the
compounds 1, are those which inhibit the wear of valve seats. Of
interest here are, for example, additives containing carboxyl
groups or their alkali metal or alkaline earth metal salts or
esters, for example copolymers of C.sub.2-C.sub.40-olefins with
maleic anhydride, having a total molar mass of from about 500 to
about 20,000, some or all of whose carboxyl groups have been
converted into the alkali metal or alkaline earth metal salts or
esters and the remainder of the carboxyl groups having reacted with
alcohols or amines, as described in EP-A 307815, or additives
containing sulfo groups or their alkali metal or alkaline earth
metal salts, for example alkali metal or alkaline earth metal salts
of alkyl sulfosuccinates, as described in EP-A 639632. The gasoline
fuel additives which inhibit the wear of valve seats can
advantageously also be used in combination with conventional fuel
detergents, such as poly(iso)buteneamines or polyetheramines, as
described in WO-A 87/01126.
[0034] The present invention also relates to fuel additive
concentrates which contain the novel alkyl-substituted aryl
polyalkoxylates (I) in amounts of from about 0.1 to about 80%, in
particular from about 0.5 to about 60% by weight, based on the
total amount of the concentrates. These concentrates can also
contain the above-mentioned detergents and further components usual
for this purpose, as well as dispersants, and solvents or diluents,
for example aliphatic and aromatic hydrocarbons, such as Solvent
Naphtha.
[0035] Further conventional components and assistants are corrosion
inhibitors, for example based on film-forming ammonium salts of
organic carboxylic acids or esters or on heterocyclic aromatics in
the case of inhibition of corrosion of nonferrous metals,
antioxidants, or stabilizers, for example based on amines such as
p-phenylenediamine, dicyclohexylamine or derivatives thereof, or on
phenols, such as 2,4-di-tert-butylphenol or
3,5-di-tert-butyl-4-hydroxyphenylpropionic acid, demulsifiers,
antistatic agents, metallocenes, such as ferrocene or
methylcyclopentadienyl manganese tricarbonyl, lubricity additives,
such as specific fatty acids and esters, alkenylsuccinic esters,
bis(hydroxyalkyl) fatty amines, hydroxyacetamides or castor oil,
and markers. Sometimes amines, too, can be added to lower the pH of
the fuel.
[0036] Further conventional carrier oils should also be mentioned
as further customary components and additives, for example mineral
carrier oils (base oils), in particular those of the viscosity
class Solvent Neutral (SN) 500 to 2000, and synthetic carrier oils
based on olefin polymers having M.sub.N=from about 400 to about
1800, especially those based on polybutene or polyisobutene
(hydrogenated or nonhydrogenated) or on polyalphaolefins or
poly(intemal olefins).
[0037] The present invention furthermore relates to fuel
compositions, in particular gasoline fuel compositions, which
contain the novel alkyl-substituted aryl polyalkoxylates (I) in
effective amounts. As a rule, effective amounts are to be
understood as meaning from about 10 to about 5000, in particular
from about 50 to about 2000, ppm by weight based on the total
amount of the composition. In addition to the novel compounds I as
carrier oils, the fuel compositions of the present invention can
contain additional detergents and dispersants as well as the stated
further components and adjuvants customary for this purpose and
solvents or diluents.
[0038] Furthermore, combinations of a gasoline fuel with a mixture
of alkyl-substituted aryl polyalkoxylates (I), and a detergent,
such as polyisobuteneamine detergents, in particular those of the
above-mentioned groups (a) through (i), and corrosion inhibitors
and/or lubricity additives based on carboxylic acids or esters or
fatty acids, which may be present as monomeric and/or dimeric
species, are particularly suitable for the novel fuel
compositions.
[0039] The novel alkyl-substituted aryl polyalkoxylates (I) of an
embodiment of the present invention are capable of reducing or
effectively avoiding the undesired "sticking of the valves", in
particular in gasoline engines. As a rule, they are also adequately
compatible with the other additives so that no separation effects
occur. Moreover, their viscosity behavior does not give rise to any
formulation problems.
[0040] The compounds I of the present invention can be used in an
embodiment as carrier oils and in another embodiment as effective
detergents. Even when metered in small amounts, the compounds of
the present invention therefore make a large contribution to the
overall performance of an additive package with respect to the
detergent effect. This provides an ability to reduce at least a
part of the conventional more expensive detergents than would
otherwise be used.
EXAMPLES
[0041] Sample A--Preparation of Adduct of Propylene Oxide or
1,2-butylene Oxide With Cresol
[0042] A 950 MW p-PIB cresol was reacted with 24 moles of liquefied
propylene oxide in the presence of a catalyst, such as potassium
hydroxide, to give the corresponding PIB cresol propoxylate having
a Mn of about 2500. The starting PIB cresol was 77% active, with
the remainder being unreacted PIB of about 1050 Mn.
[0043] Sample B--Preparation of Adduct of Propylene Oxide with
Cresol
[0044] A 208 MW p-PIB cresol was reacted with 24 moles of liquefied
propylene oxide in the presence of a catalyst, such as potassium
hydroxide, to give corresponding PIB cresol propoxylate having a Mn
of about 1444. The starting PIB cresol was 74.6% active, with the
remainder being 16% unreacted PIB of 325 MW, and 6.5% of mixed
t-amylit-butyl cresols.
[0045] Testing of Performance Characteristics
[0046] Tests on the cleanliness of intake valves were carried out
in a 2.3-liter Ford, 4 cylinder, 2-valve engine according to the
IVD test method ASTM D-6210. Fuels were prepared using 43.7 pounds
per thousand barrels (PTB) active solids in which the detergent was
HiTEC.RTM. 6410 (a PIB-substituted Mannich detergent available from
Ethyl Corporation) at a treat rate of 23.4 PTB of gasoline. The
samples also contained a 750 MW PIB carrier fluid at a treat rate
of 10.3 PTB. The prior art carrier fluid used in Comparative Sample
1 (and a duplicate Comparative Sample 2) was a nonyl phenol
propoxylate reacted with 24 moles of propylene oxide. The carrier
fluids in the inventive samples were A and B, prepared as described
herein. All carrier fluid polyols were used at a dose rate of 10
PTB.
[0047] The results of the IVD test are shown below:
1 Average IVD (mg) Comparative Sample 1 92.6 Comparative Sample 2
104.0 Inventive Sample A 54.0 Inventive Sample B 63.1
[0048] As evident from the above Table, the inventive additive
packages A and B provided a significant reduction in deposit
formation on the intake valves in the test engine, relative to the
deposits resulting from the combustion of fuel not containing the
alkyl-substituted aryl polyalkoxylates of the present invention. In
general, the industry recognizes a pass limit of about 100 mg or
less average deposit formation per intake valve. Specifically, the
63.1 mg and 54.0 mg average IVD deposits are surprisingly improved
over the 92.6 mg and the 104.0 mg of the prior art fuel
samples.
[0049] In addition, the inventive samples A and B were compared to
the conventional carrier fluids of Comparative Sample 1 in a
seven-day Vanagon valve sticking test at 0 degree F. The test is
designed to mirror the well-known European Wasserboxer test (CEC
F-16-T-96). A "Pass" is obtained by no loss of compression in the
engine fuieled by the fuel sample being tested, whereas a "Fail" is
indicated when there is zero compression, caused by a stuck (open)
valve. The test results are shown below:
2 Comparative Sample 1 Fail Inventive Sample A Pass Inventive
Sample B Pass
[0050] The results illustrate the improved valve sticking
performance achieved by the use of the fuel compositions of the
present invention combusted in a gasoline engine, relative to the
valve sticking performance of a fuel composition without the
inventive fuel additive.
[0051] This invention is susceptible to considerable variation in
its practice. Accordingly, this invention is not limited to the
specific exemplifications set forth hereinabove. Rather, this
invention is within the spirit and scope of the appended claims,
including the equivalents thereof available as a matter of law.
[0052] The patentee does not intend to dedicate any disclosed
embodiments to the public, and to the extent any disclosed
modifications or alterations may not literally fall within the
scope of the claims, they are considered to be part of the
invention under the doctrine of equivalents.
* * * * *