  United States Court of Appeals
      for the Federal Circuit
                ______________________

          AKZO NOBEL COATINGS, INC.,
                Plaintiff-Appellant

                           v.

            DOW CHEMICAL COMPANY,
              Defendant-Cross-Appellant
               ______________________

                 2015-1331, 2015-1389
                ______________________

    Appeals from the United States District Court for the
District of Delaware in No. 1:12-cv-01264-LPS, Chief
Judge Leonard P. Stark.
                ______________________

               Decided: January 29, 2016
                ______________________

   ELIZABETH GARDNER, Kenyon & Kenyon LLP, New
York, NY, argued for appellant. Also represented by
MICHAEL D. LOUGHNANE, RICHARD DELUCIA, MERRI C.
MOKEN.

    AARON A. BARLOW, Jenner & Block LLP, Chicago, IL,
argued for cross-appellant. Also represented by PAUL
DAVID MARGOLIS, HARRY J. ROPER; JOSHUA SEGAL, Wash-
ington, DC.
                ______________________
2      AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



    Before LOURIE, REYNA, and CHEN, Circuit Judges.
LOURIE, Circuit Judge.
     Akzo Nobel Coatings, Inc. (“Akzo”) appeals from the
decision of the United States District Court for the Dis-
trict of Delaware granting summary judgment that Dow
Chemical Company (“Dow”) did not infringe the claims of
U.S. Patent 6,767,956 (“the ’956 patent”), either literally
or under the doctrine of equivalents. Akzo Nobel Coat-
ings, Inc. v. Dow Chem. Co., No. 1:12-cv-01364 (D. Del.
Jan. 26, 2015) (“Decision”). Dow cross-appeals from the
court’s conclusion that the claims of the ’956 patent are
not indefinite. Id. at 10–14. For the reasons that follow,
we affirm both appeals.
                       BACKGROUND
    Akzo owns by assignment the ’956 patent, directed to
an extrusion process that generates low viscosity aqueous
polymer dispersions. ’956 patent, at [57]. In order to
achieve uniform distribution of the polymer in the aque-
ous medium, the specification notes that “the mixture
cannot be heated above the boiling point of the carrier
liquid, or else the liquid boils and it becomes impossible to
disperse the polymer.” Id. col. 1 ll. 57–59. The claimed
invention aims to prevent such boiling, and thus achieve
uniform polymer distribution, by maintaining the pres-
sure in the extruder above atmospheric. Id. col. 2 ll. 26–
33. Specifically, “[t]he pressure in the extruder [is] main-
tained by . . . connecting the outlet of the extruder to a
pressurized collection vessel.” Id. col. 2 l. 64–col. 3 l. 1.
    Claim 1 is representative and reads as follows:
    1. A process for producing a dispersion of a poly-
       mer in an aqueous medium in which the poly-
       mer is dispersed in an aqueous medium in an
       extruder at a temperature above 100° C. in an
       extruder having an outlet
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY         3



        wherein the pressure in the extruder is main-
        tained above atmospheric so that the aqueous
        medium does not boil characterized by main-
        taining the pressure above atmospheric for the
        extruder at the outlet with a pressurized collec-
        tion vessel and
        wherein aqueous dispersion from the extruder
        has at least 25% by weight of the aqueous me-
        dium where the aqueous medium has less than
        40% by weight of organic solvent and
        wherein the aqueous dispersion enters the out-
        let and pressurized collection vessel at a pres-
        sure above atmospheric so that the aqueous
        medium does not boil and is subjected to the
        action of a cooling zone to lower the tempera-
        ture of the aqueous dispersion to below 100° C.
        to have an aqueous dispersion with a viscosity
        below 10 Pa.s.
Id. col. 7 l. 9–col. 8 l. 4 (emphases added). Claim 2 further
requires: “[a] process according to claim 1 which is carried
out at a temperature of from about 5 to 150° C. above the
melting point of the polymer.” Id. col. 8 ll. 5–7 (emphasis
added). 1
    Dow’s accused process, called BLUEWAVE™, uses an
extruder to generate low viscosity polymer dispersions. In
Dow’s process, the dispersion exits the extruder, passes
through a valve located at the extruder’s outlet, and then
travels through a series of pipes and heat exchangers.


    1    Claims 1–8 all contain the disputed “pressurized
collection vessel” and “viscosity below 10 Pa.s” limitations.
Claims 2–6 further contain the disputed “carried out . . .
of the polymer” limitation. The parties only rely on those
three limitations in challenging the district court’s judg-
ment.
4      AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



Joint App. (“J.A.”) 1012, 1040–41. The dispersion then
continues on through a filter and collects in a “Product
Tote,” an unpressurized compartment, eventually used to
transport the end-product. J.A. 1012.
    In October 2012, Akzo sued Dow for patent infringe-
ment, alleging that Dow’s BLUEWAVE™ process in-
fringed claims 1–8 of the ’956 patent. In view of what it
considered to be Akzo’s failure to identify any “pressur-
ized collection vessel” in the accused process, Dow sought
leave of court to file an early summary judgment motion
of noninfringement. J.A. 685–88. The district court
granted the request and combined the summary judgment
and Markman hearings. J.A. 52–53.
     After the combined hearings, the district court first
construed several disputed limitations. Decision at 6–14.
It construed “pressurized collection vessel” as “tubing,
piping, or other container where a desired material accu-
mulates, which is maintained above atmospheric pres-
sure.” Id. at 6–7. The court reasoned that, to properly
give meaning to the word “collection,” “some amount of
material must be permitted to accumulate within the
vessel, rather than all of the material flowing through the
vessel at a constant rate.” Id. at 7. It specifically relied
on two examples in the specification, Examples 2 and 3,
id., which state: “[t]he dispersion was collected into a
water-cooled pressurized vessel maintained under nitro-
gen at 7 bar and from which the dispersion, once cooled to
below 100° C., could be periodically removed,” ’956 patent
col. 6 ll. 40–44, col. 7 ll. 1–4 (emphases added).
    The district court next addressed and rejected Dow’s
contention that the limitation “viscosity below 10 Pa.s”
rendered claims 1–8 indefinite. According to Dow, the
limitation could be definite only if it incorporated a re-
quirement that the viscosity be tested at a certain tem-
perature; a failure to require such a temperature, Dow
suggested, was fatal. The court disagreed, instead finding
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY       5



that “in context one of ordinary skill in the art would
know with reasonable certainty that viscosity is to be
measured at room temperature.” Id. at 11. It accordingly
construed “viscosity below 10 Pa.s” to mean “viscosity
below 10 Pa.s at room temperature.” Id. at 10.
    The court then addressed and rejected Dow’s conten-
tion that the limitation “carried out at a temperature of
from 5 to 150° C. above the melting point of the polymer”
rendered claims 2–6 indefinite. Specifically, Dow argued
that the limitation failed to specify to which steps in the
claimed process it applied, and that simply applying the
limitation to every step, as the plain meaning suggests,
would be irrational, for many steps require a temperature
at or below 100° C. The court disagreed, however, instead
finding that the specification explains that only a subset
of steps in the claimed process occurs at elevated temper-
atures, id. at 14 (citing ’956 patent col. 2 ll. 38–41), and
therefore “the limitation in claim 2 refers to the elevated
temperature phases,” id. The court concluded: “Dow has
provided no evidence to show that a person of ordinary
skill in the art would not know with reasonable certainty
the steps to which the limitation in claim 2 applies.” Id.
It accordingly construed the limitation to mean “[t]he
elevated temperature phases of claim 1 are carried out at
a temperature of from 5 to 150° C above the melting point
of the polymer.” Id. at 13.
    In light of the above constructions, the district court
granted Dow’s motion for summary judgment of nonin-
fringement of claims 1–8. In describing Dow’s accused
process, the court found that “Dow’s accused process uses
a valve and allows the polymer dispersion to flow continu-
ously. It does not accumulate.” Id. at 17. That lack of
accumulation precluded a finding of literal infringement.
Indeed, as the court noted: “no reasonable juror could find
that Dow’s accused process uses a ‘pressurized collection
[vessel]’” because “a reasonable juror could only find that
the accused BLUEWAVE™ process allows for the polymer
6      AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



dispersion to flow continuously.” Id. The lack of accumu-
lation likewise precluded a finding of infringement under
the doctrine of equivalents. As the court found, “[t]o allow
Akzo to prevail on infringement by the doctrine of equiva-
lents would vitiate the claim limitation that the ‘pressur-
ized collection vessel’ be a ‘container where the desired
material accumulates.’” Id. at 18.
   Akzo timely appealed and Dow timely cross-appealed.
We have jurisdiction pursuant to 28 U.S.C. § 1295(a)(1).
                        DISCUSSION
                     I. Akzo’s Appeal
     We review the district court’s grant of summary
judgment under the law of the regional circuit, here, the
Third Circuit. Halo Elecs., Inc. v. Pulse Elecs., Inc., 769
F.3d 1371, 1377 (Fed. Cir. 2014). Applying the law of the
Third Circuit, we review the grant of summary judgment
de novo. Nicini v. Morra, 212 F.3d 798, 805 (3d Cir. 2000)
(en banc). Summary judgment is proper when, drawing
all justifiable inferences in the non-movant’s favor, “there
is no genuine dispute as to any material fact and the
movant is entitled to judgment as a matter of law.” Fed.
R. Civ. P. 56(a); Anderson v. Liberty Lobby, Inc., 477 U.S.
242, 255 (1986).
    Evaluation of summary judgment of noninfringement
is a two-part inquiry: construing the claims and compar-
ing the properly construed claims to the accused product.
Abbott Labs. v. Sandoz, Inc., 566 F.3d 1282, 1288 (Fed.
Cir. 2009). We review de novo the ultimate interpretation
of a claim term and the evidence intrinsic to the patent.
Teva Pharm. USA, Inc. v. Sandoz, Inc., 574 U.S. ___, 135
S. Ct. 831, 841 (2015). When a district court makes
factual findings about extrinsic evidence, we review those
subsidiary factual findings for clear error. Id. at 835, 841.
   Infringement, whether literal or under the doctrine of
equivalents, is a question of fact. Absolute Software, Inc.
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY         7



v. Stealth Signal, Inc., 659 F.3d 1121, 1129–30 (Fed. Cir.
2011). As such, it is amenable to summary judgment
when no reasonable factfinder could find that the accused
product contains every claim limitation or its equivalent.
PC Connector Sols., LLC v. SmartDisk Corp., 406 F.3d
1359, 1364 (Fed. Cir. 2005); see Warner-Jenkinson Co. v.
Hilton Davis Chem. Co., 520 U.S. 17, 29, 39 n.8 (1997).
                    A. Claim Construction
    On appeal, Akzo first faults the district court for nar-
rowly construing “pressurized collection vessel” to require
accumulation. Akzo argues that the term should instead
assume its ordinary meaning of “gather or receive.” Akzo
contends that such a construction is supported by both the
claim language and specification, neither of which re-
quires the dispersion to be held for a period of time.
According to Akzo, the court’s construction imports fur-
ther, unspecified process limitations on how long the
dispersion must be in the vessel and the manner by which
the dispersion exits the vessel, among others. See Appel-
lant’s Br. 34.
    Dow responds that “collection,” in context, necessarily
requires accumulation, as the district court held. Dow
relies primarily on Examples 2 and 3 in the specification,
which state: “from which the dispersion, once cooled to
below 100° C., could be periodically removed.” Appellee’s
Br. 28 (quoting ’956 patent col. 6 ll. 40–44, col. 7 ll. 1–4).
According to Dow, “‘once cooled’ implies . . . that the
material is sitting there and ‘periodically removed’ re-
quires not immediately removed; it is removed after a
period of time. Both of those assume that accumulation
has occurred.” Oral Argument 14:30–14:42. Moreover,
Dow contends, construing the term to broadly mean
“gather or receive” renders the limitation superfluous
because, under a “gather or receive” construction, any
pressurized vessel is a “pressurized collection vessel.”
8      AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



     We agree with Dow and affirm the district court’s con-
struction of “pressurized collection vessel” as “tubing,
piping, or other container where a desired material accu-
mulates, which is maintained above atmospheric pres-
sure.” Our claim construction analysis begins with the
language of the claim itself, as it would have been under-
stood by one of ordinary skill in the art at the time of the
invention. Phillips v. AWH Corp., 415 F.3d 1303, 1312–13
(Fed. Cir. 2005) (en banc). The claims “must be read in
view of the specification, of which they are a part.” Id. at
1315 (quoting Markman v. Westview Instruments, Inc., 52
F.3d 967, 979 (Fed. Cir. 1995) (en banc)). Indeed, we have
said that the specification “is always highly relevant to
the claim construction analysis. Usually, it is dispositive;
it is the single best guide to the meaning of a disputed
term.” Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576,
1582 (Fed. Cir. 1996).
    As an initial matter, we agree with the district court
that adopting Akzo’s proffered construction of “gather or
receive” would “obviate[] the import of the word ‘collec-
tion.’” Decision at 7. There is no dispute that the “pres-
surized collection vessel” receives the dispersion; that
function is clearly contemplated by the surrounding claim
language. ’956 patent col. 7 ll. 19–21 (“[T]he aqueous
dispersion enters the outlet and pressurized collection
vessel at a pressure above atmospheric.”). But allowing
“collection” to mean “receive” would render “collection”
entirely superfluous and allow any pressurized vessel to
constitute a “pressurized collection vessel”; such a result
is disfavored. Merck & Co. v. Teva Pharm. USA, Inc., 395
F.3d 1364, 1372 (Fed. Cir. 2005) (“A claim construction
that gives meaning to all the terms of the claim is pre-
ferred over one that does not do so.”); Power Mosfet Techs.,
L.L.C. v. Siemens AG, 378 F.3d 1396, 1410 (Fed. Cir.
2004) (“[I]nterpretations that render some portion of the
claim language superfluous are disfavored.”). The district
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY        9



court’s construction of “accumulation,” on the other hand,
gives the term “collection” proper meaning in context.
     Moreover, the remainder of the specification supports
the court’s construction. In addition to the limitation
itself, “collection” and/or “collected” is used twice in the
specification, in Examples 2 and 3. ’956 patent col. 6 l. 40,
col. 7 l. 1. In those examples, the dispersion is collected,
allowed to cool, and then “periodically removed.” Id. col. 6
l. 43, col. 7 l. 4. Those examples clearly contemplate a
buildup or accumulation of dispersion in the collection
vessel before the eventual “periodic removal.” Thus, as
the court noted, to give meaning to “collection” consistent
with the specification, “material must be permitted to
accumulate within the vessel, rather than all of the
material flowing through the vessel at a constant rate.”
Decision at 7; cf. Kinetic Concepts, Inc. v. Blue Sky Med.
Grp., Inc., 554 F.3d 1010, 1018–19 (Fed. Cir. 2009) (con-
struing “wounds” as “skin wounds” because “[a]ll of the
examples described in the specification involve skin
wounds,” and construing otherwise “would thus expand
the scope of the claims far beyond anything described in
the specification”).
                   B. Literal Infringement
    Akzo next argues that it has raised a genuine issue of
material fact as to literal infringement under the court’s
construction of “pressurized collection vessel.” 2 According
to Akzo, it proved “substantial facts to rebut Dow’s claims
regarding the function of its control valve,” and provided
“unrebutted evidence to support a finding that dispersion
‘accumulates’ in Dow’s heat exchange equipment,” includ-



    2   Because we affirm the district court’s construction
of “pressurized collection vessel,” we need not address
Akzo’s arguments regarding infringement under Akzo’s
proffered construction.
10     AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



ing inspections of Dow’s BLUEWAVE™ process and the
expert declaration of Dr. Eldridge M. Mount III. Appel-
lant’s Br. 46, 48 (referencing J.A. 1098 ¶ 46).
     Dow responds that Akzo did not provide sufficient ev-
idence from which a reasonable jury could find accumula-
tion. Moreover, Dow contends, the declaration Akzo relies
on fails to create a genuine issue of material fact because
it is ambiguous at best about whether dispersion “accu-
mulates” in the heat exchangers.
     We agree with Dow and the district court that Akzo
failed to raise a genuine issue of material fact as to literal
infringement, and thus affirm the district court’s grant of
summary judgment of no literal infringement. All of the
claims contain the “pressurized collection vessel” limita-
tion and are thus subject to the same analysis and conclu-
sion.
    Literal infringement exists when every limitation re-
cited in the claim is found in the accused device. Cole v.
Kimberly-Clark Corp., 102 F.3d 524, 532 (Fed. Cir. 1996).
On appeal from a grant of summary judgment of no literal
infringement, we determine, after resolving all inferences
in favor of the patentee, whether the district court correct-
ly concluded that no reasonable jury could find infringe-
ment. Move, Inc. v. Real Estate Alliance Ltd., 709 F.3d
1117, 1121 (Fed. Cir. 2013).
     As the movant, Dow had “the initial responsibility of
identifying the legal basis of its motion, and of pointing to
those portions of the record that it believes demonstrates
the absence of a genuine issue of material fact.” Novartis
Corp. v. Ben Venue Labs., Inc., 271 F.3d 1043, 1046 (Fed.
Cir. 2001). Dow satisfied this burden by identifying that
its accused process lacks a “pressurized collection vessel,”
as construed, and by pointing to record evidence suggest-
ing that, in its process, “the material continuously passed
through the heat exchangers.” J.A. 914 (“Dow’s disper-
sion is only collected at the very end of the Dow process in
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY      11



a large open-to-the-atmosphere plastic crate or an even
larger, open-to-the-atmosphere storage tank, neither of
which is pressurized.”). Accordingly, “the burden shift[ed]
to [Akzo] to designate specific facts showing that there is
a genuine issue for trial.” Novartis, 271 F.3d at 1046.
The court correctly determined that Akzo failed to meet
that burden.
    For its part, Akzo had to present evidence that the
dispersion accumulates in Dow’s downstream heat ex-
changers and pipes. Akzo primarily relied on the declara-
tion of its expert, Dr. Mount, which stated that the piping
“represents a defined volume of space in which the disper-
sion collects and is resident for a period of time such that
a backpressure is created” on the extruder. J.A. 1098
¶ 46. According to Akzo, that “unrebutted” statement
established a genuine issue of material fact as to whether
Dow’s pipes and heat exchangers “accumulate” dispersion,
as required by the claims.
     We disagree. Dr. Mount’s statement is ambiguous at
best as to whether accumulation occurs in Dow’s accused
process. It does not recite “accumulation,” nor does it
expressly refute Dow’s contention that dispersion flows
continuously throughout its process and does not accumu-
late. Akzo instead relies heavily on Dr. Mount’s language,
“resident for a period of time.” Such reliance is misplaced,
however, for such a phrase does not invoke the “accumu-
lation” envisioned by the claims, and certainly, as Dow
notes, “liquid passing through pipes is always ‘resident for
a period of time.’” Appellee’s Br. 47. Ultimately, the
passage states that “dispersion collects,” yet it fails to
identify which construction of “collection” it relies on.
Such evidence did not establish a genuine issue of materi-
al fact.
    Accordingly, Akzo failed to provide sufficient evidence
from which a reasonable jury could find that the disper-
sion in Dow’s process accumulates within a “pressurized
12     AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



collection vessel.” The district court’s grant of summary
judgment of no literal infringement of all the claims was
therefore correct.
     C. Infringement Under the Doctrine of Equivalents
    Akzo lastly contends that the district court committed
legal error by applying the concept of vitiation and im-
permissibly creating “a ‘binary choice’ in which an ele-
ment is either present or ‘not present.’” Appellant’s Br. 52
(quoting Deere & Co. v. Bush Hog, LLC, 703 F.3d 1349,
1356 (Fed. Cir. 2012)). Under a correct application of the
doctrine of equivalents, Akzo argues, it raised a genuine
issue of material fact as to whether Dow’s equipment
performed the same function in substantially the same
way to reach the same result.
    Dow responds that the district court engaged in the
proper “function-way-result” inquiry and simply conclud-
ed that Akzo failed to meet its burden of showing a genu-
ine issue of material fact.
    We agree with Dow and affirm the district court’s
grant of summary judgment of no infringement under the
doctrine of equivalents. Although infringement under the
doctrine of equivalents is a question of fact, summary
judgment is proper “[w]here the evidence is such that no
reasonable jury could determine two elements to be
equivalent.” Warner-Jenkinson, 520 U.S. at 39 n.8. A
patentee must establish “equivalency on a limitation-by-
limitation basis” by “particularized testimony and linking
argument” as to the insubstantiality of the differences
between the claimed invention and the accused device or
process. Texas Instruments Inc. v. Cypress Semiconductor
Corp., 90 F.3d 1558, 1566 (Fed. Cir. 1996). The function-
way-result test “often suffice[s] to show the substantiality
of the differences.” Id. “[A]ll claim limitations are not
entitled to an equal scope of equivalents.” Moore USA,
Inc. v. Standard Register Co., 229 F.3d 1091, 1106 (Fed.
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY      13



Cir. 2000). Ultimately, “many limitations warrant little,
if any, range of equivalents.” Id.
    Akzo hones in on and challenges the district court’s
use of “vitiate” in its equivalents analysis. We find this
challenge unpersuasive. As the Supreme Court has
stated, “if a theory of equivalence would entirely vitiate a
particular claim element, partial or complete judgment
should be rendered by the court . . . .” Warner-Jenkinson,
520 U.S. at 39 n.8. The dictionary defines the term “viti-
ate” as “to make ineffective.” See MERRIAM WEBSTER,
http://www.merriam-webster.com/dictionary/vitiate (last
visited Dec. 15. 2015). Under the doctrine of equivalents,
an infringement theory thus fails if it renders a claim
limitation inconsequential or ineffective. And as we have
explained, “saying that a claim element would be vitiated
is akin to saying that there is no equivalent to the claim
element in the accused device based on the well-
established ‘function-way-result’ or ‘insubstantial differ-
ences’ tests.” Brilliant Instruments, Inc. v. GuideTech,
LLC, 707 F.3d 1342, 1347 (Fed. Cir. 2013) (emphasis
added); cf. Cadence Pharm. Inc. v. Exela PharmSci Inc.,
780 F.3d 1364, 1372 (Fed. Cir. 2015) (“The determination
of equivalence depends not on labels like ‘vitiation’ or
‘antithesis’ but on the proper assessment of the language
of the claimed limitation and the substantiality of what-
ever relevant differences may exist in the accused struc-
ture.”).
     With these principles in mind, we conclude that Akzo
failed to establish a genuine issue of material fact as to
whether Dow’s process operates in substantially the same
way. In fact, the opposite is true. The claimed process
operates by using a pressurized collection vessel wherein
dispersion accumulates to maintain backpressure in the
extruder. To state it differently, it is the accumulation of
dispersion in the collection vessel that generates the
backpressure. Dow’s accused process, on the other hand,
“uses a valve” and does not allow for accumulation in the
14      AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



downstream pipes. Decision at 17. Thus, in order to
survive summary judgment, Akzo had to show that a
valve and a series of pipes and heat exchangers, wherein
the dispersion flows continuously, generate backpressure
in the extruder in substantially the same way to increase
the boiling point of the carrier fluid. It did not do so.
    Akzo introduced Dr. Mount’s declaration as support.
In the last paragraph of a fifty-one paragraph declaration,
Dr. Mount states:
     Dow’s and Michelman’s piping and heat exchang-
     ers perform the same function (maintain the pres-
     sure) and achieve the same result (maintaining
     sufficient pressure to prevent boiling of the aque-
     ous medium) in substantially the same way (by
     collecting the dispersed material in a contained
     volume) as the vessel used by the inventors in Ex-
     amples 2 and 3 of the patent.
J.A. 1100–01. Dr. Mount’s discussion of the doctrine of
equivalents is broad and scant. Telemac Cellular Corp. v.
Topp Telecom, Inc., 247 F.3d 1316, 1329 (Fed. Cir. 2001)
(“Broad conclusory statements offered by Telemac’s expert
are not evidence and are not sufficient to establish a
genuine issue of material fact.”). Nevertheless, what
truly undermines Akzo’s reliance on the above-quoted
statement is the statement’s failure to articulate how
Dow’s accused process operates in substantially the same
way. Dr. Mount states that Dow’s process operates “in
substantially the same way (by collecting the disperse
material in a contained volume),” yet he fails to articulate
which construction of “collecting” he invokes, much less
articulate how the differences between the two processes
are insubstantial. Such ambiguity and generality cannot
create a genuine issue of material fact.
    Accordingly, Akzo failed to provide evidence from
which a reasonable jury could find that Dow’s valve,
pipes, and heat exchangers operate in substantially the
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY       15



same way as the claimed “pressurized collection vessel” to
generate backpressure in the extruder. The court’s grant
of summary judgment was therefore correct. 3
                  II. Dow’s Cross-Appeal
    In its cross-appeal, Dow challenges the district court’s
conclusion that the claims of the ’956 patent are not
invalid for indefiniteness. Specifically, Dow contests two
limitations. First, Dow argues that “viscosity below 10
Pa.s” renders claims 1–8 indefinite because it fails to
recite the temperature at which the viscosity measure-
ment is to be taken. Second, Dow argues that “carried out
at a temperature of from 5 to 150° C. above the melting
point of the polymer” renders claims 2–6 indefinite be-
cause it fails to specify which steps in the claimed process
occur at those elevated temperatures.
     Indefiniteness is a question of law that we review de
novo, Interval Licensing LLC v. AOL, Inc., 766 F.3d 1364,
1370 (Fed. Cir. 2014), subject to a determination of under-
lying facts. A patent claim is invalid for indefiniteness if
its language, when read in light of the specification and
prosecution history, “fail[s] to inform, with reasonable
certainty, those skilled in the art about the scope of the
invention.” Nautilus, Inc. v. Biosig Instruments, Inc., 572
U.S. ____, 134 S. Ct. 2120, 2124 (2014). Patents are
presumed to be valid, and the challenger bears the burden
of establishing invalidity. See 35 U.S.C. § 282; Nautilus,
134 S. Ct. at 2130 n.10.
    We first address the “viscosity below 10 Pa.s” limita-
tion. The district court’s determination that one of skill in
the art would measure viscosity at room temperature in


    3    As we agree with the reasoning relied on by the
district court in affirming the grant of summary judgment
of no infringement, we find it unnecessary to consider
Dow’s alternative grounds for affirmance.
16     AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



the absence of a specified temperature was based on
extrinsic evidence. Because we see no clear error in that
fact finding here, and it does not conflict with the intrinsic
record, we affirm. See Teva Pharm. USA, Inc. v. Sandoz,
Inc., 789 F.3d 1335, 1342 (Fed. Cir. 2015); Biosig Instru-
ments, Inc. v. Nautilus, Inc., 783 F.3d 1374, 1378 (Fed.
Cir. 2015).
    The district court considered, inter alia, two pieces of
extrinsic evidence: Dr. Mount’s declaration, J.A. 482–83,
and the ASTM protocol, J.A. 542–49. Dr. Mount’s decla-
ration, in part, recites: “[t]he standard practice in analyti-
cal chemistry dictates that if a temperature is not
specified for a given measurement, room temperature is
implied.” J.A. 482 ¶ 18. The ASTM protocol, on the other
hand, relays a “test method [for] the determination of the
apparent viscosity of hot melt adhesives . . . at tempera-
tures up to 175° C.” J.A. 542. The method then requires
“report[ing] the apparent viscosity at a given temperature
along with the particulars . . . .” J.A. 543.
     The district court did not clearly err in crediting Dr.
Mount’s declaration over the ASTM protocol. The ASTM
protocol does indicate that viscosity varies with tempera-
ture. But the described method only discusses “hot melt
adhesives” above 175° C, which is inapposite to the
claimed product that has been cooled to below 100° C,
aims to find different viscosities over a range of tempera-
tures, and fails to indicate what a skilled artisan would
understand. Accordingly, the court correctly discounted
the ASTM protocol to find that one of skill would under-
stand that room temperature is implied for a viscosity
measurement with no specified temperature. As the court
then noted, Dow “fail[ed] to establish by clear and con-
vincing evidence that a person skilled in the art would not
know with reasonable certainty at what temperature to
measure viscosity.” Decision at 11.
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY       17



     Moreover, although the district court did not express-
ly rely on the intrinsic record, we conclude that the intrin-
sic record only further supports the court’s determination.
Granted, neither the claim language nor the specification
indicates a temperature for the final viscosity measure-
ment. But room temperature is the only temperature
mentioned at all in the ’956 patent in connection with a
viscosity measurement. ’956 patent col. 3 l. 23. Accord-
ingly, we affirm the court’s conclusion that the expression
“viscosity below 10 Pa.s” does not render claims 1–8
indefinite, as well as its construction of that limitation as
“viscosity below 10 Pa.s at room temperature.”
     We next address the “carried out . . . of the polymer”
limitation. 4 The process recited in claim 2 is “a process
according to Claim 1.” Id. col. 8 ll. 5–8. Claim 1 recites a
process “for producing a dispersion in an aqueous medium
in which the polymer is dispersed in an aqueous medium
in an extruder at a temperature above 100° C.” Id. col. 7
ll. 9–11. The specification then teaches that the dispers-
ing step necessarily takes place before the dispersion exits
the extruder; it is during that dispersing step when the
temperature exceeds the melting point of the polymer.
Indeed, the specification describes a typical process where
the polymer “is melted in the initial melt zone of the
extruder at a temperature above the melting point of the
polymer, preferably from 5 to 150° C, typically 10 to 130°
C, above the melting point.” Id. col. 2 ll. 36–41. Thus, as
the district court found, “the specification supports a
construction which indicates that the limitation in claim 2
refers to the elevated temperature phases and not to the
stages that follow.” Decision at 14.




    4   Claims 2–6 all contain the same “carried out . . . of
the polymer” limitation and are thus subject to the same
analysis.
18     AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY



    Further, in concluding that claims 2–6 were not indef-
inite, the district court stated that “Dow has provided no
evidence to show that a person of ordinary skill in the art
would not know with reasonable certainty the steps to
which the limitation in claim 2 applies.” Decision at 14.
Absent any evidence contrary to the clear meaning of the
intrinsic record, the court did not err in finding that one of
skill in the art would understand which steps the elevated
temperature range applied to. See id.
    Dow suggests that, in affirming the district court’s
construction, we run afoul of the principle that courts may
not redraft claims to sustain their validity. Appellee’s Br.
67–68 (discussing Chef Am., Inc. v. Lamb-Weston, Inc.,
358 F.3d 1371 (Fed. Cir. 2004)). Dow’s reliance on Chef
America, however, is misplaced. In affirming the district
court’s construction, we are not redrafting the claims, but
rather construing the claims to require the heightened
temperature range to apply to the elevated temperature
phases in accordance with the specification. Eidos Dis-
play, LLC v. AU Optronics Corp., 779 F.3d 1360, 1367–68
(Fed. Cir. 2015) (“Determining how a person of ordinary
skill in the art would understand the limitation, however,
is different from rewriting the limitation.”); Wellman, Inc.
v. Eastman Chem. Co., 642 F.3d 1355, 1366–67 (Fed. Cir.
2011).
    Accordingly, we affirm the district court’s conclusion
that “carried out . . . of the polymer” does not render
claims 2–6 indefinite, as well as its construction of that
limitation as “[t]he elevated temperature phases of claim
1 are carried out at a temperature of from 5 to 150° C
above the melting point of the polymer.”
                        CONCLUSION
     We have considered all remaining arguments, but find
them unpersuasive. For the reasons set forth above, we
affirm the judgment of the district court.
AKZO NOBEL COATINGS, INC.   v. DOW CHEMICAL COMPANY   19



                      AFFIRMED
