No Spill Inc.

Patent Trials and Appeals Board

Jul 2, 2021

IPR2020-00360 (P.T.A.B. Jul. 2, 2021)

Trials@uspto.gov Paper 27
Tel: 571-272-7822 Entered: July 2, 2021

UNITED STATES PATENT AND TRADEMARK OFFICE
_______________
BEFORE THE PATENT TRIAL AND APPEAL BOARD
_______________
SCEPTER CANADA, INC.,
Petitioner,

v.

NO SPILL INC.,
Patent Owner.
____________

IPR2020-00360
Patent 10,029,132 B2
____________

Before SCOTT C. MOORE, FREDERICK C. LANEY, and
SEAN P. O’HANLON, Administrative Patent Judges.

MOORE, Administrative Patent Judge.

JUDGMENT
Final Written Decision
Determining No Challenged Claims Unpatentable
35 U.S.C. § 318(a)

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I. INTRODUCTION
Scepter Canada, Inc. (“Petitioner”) filed a petition requesting inter
partes review of claims 1–18 of U.S. Patent No. 10,029,132 B2 (Ex. 1001,
“the ’132 Patent”). Paper 2 (“Pet.”). No Spill Inc. (“Patent Owner”) filed a
Preliminary Response. Paper 6. We instituted an inter partes review as to
all claims and grounds set forth in the Petition. Paper 7.
After institution, Patent Owner filed a response to the Petition (Paper
11, “Response” or “Resp.”), Petitioner filed a reply to the Response (Paper
14, “Reply”), and Patent Owner filed a sur-reply (Paper 19, “Sur-Reply”).
Oral arguments took place on April 8, 2021.
We have jurisdiction under 35 U.S.C. § 6. This Final Written
Decision is issued pursuant to 35 U.S.C. § 318(a). For the reasons that
follow, we determine that Petitioner has not shown by a preponderance of
the evidence that any of the challenged claims is unpatentable.
A. Related Matters
Petitioner also challenged U.S. Patent No. 9,174,075, which is the
parent application of the ’132 Patent, in IPR2020-00361. We declined to
institute an inter partes review of that patent. IPR2020-00361, Paper 7.
According to the parties, the ’132 Patent is involved in No Spill Inc. v.
Scepter Corporation n/k/a 1216037 Ontario Inc., et al., Case No. 2:18-cv-
02681-JAR-KGG (D. Kan.). Pet. 2; Paper 5, 2–3 (Patent Owner’s
Mandatory Notice).
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B. Real Parties In Interest
Petitioner asserts that Scepter Canada, Inc. and Myers Industries, Inc.
are the real parties in interest. Pet. 2. Patent Owner asserts that No Spill
Inc. is the real party in interest. Paper 5, 2.
C. Technology Background
This case involves safety features on portable fuel containers,
specifically those safety features to prevent explosions of the container.
According to the ’132 Patent, most modern fuel containers work well under
normal circumstances, but “explosions within fuel containers have been
induced by researchers in highly-controlled, extreme laboratory
environments.” Ex. 1001, 1:54–61.
Combustion requires a combination of oxygen and fuel in the
presence of an ignition source. Ex. 1001, 1:47–50. The ratio of air to fuel is
important because combustion cannot occur when there is too little fuel and
too much air (a “lean mixture”), or when there is too much fuel and too little
air (a “rich mixture”). Id. at 2:43–55. But “when fuel and air are present
and their mixture is within a given combustible range, combustion will occur
if the mixture is ignited.” Id. at 2:43–46.
Typically, the high volatility of fuel (e.g., gasoline) produces
sufficient vapors inside the container to make the air-fuel mixture too rich to
support combustion. Ex. 1010, 4 (Brian Elias, Hazard Assessment of
Portable Gasoline Container Flammability, Worchester Polytechnic
Institute (2011) (“Elias”)). However, in certain conditions, “such as small
liquid volumes, low temperatures, or certain pour angles, a flammable region
can develop in this space.” Id. This type of scenario is illustrated in Figure
1 of Elias, which is reproduced below.
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Figure 1 of Elias depicts a portable gasoline container (“PGC”) having a
relatively low fuel level, “where a flammable vapor zone exists in the area
between the liquid gasoline and the pour spout tip.” Ex. 1010, 4–5. “The
lower area close to the liquid surface is above the upper flammable limit,
while the area farthest from the liquid is below the lower flammable limit.”
Id. at 4.
The ’132 Patent indicates that it was known in the prior art to use
flame arrestors1 to minimize the risk of portable fuel can explosions. Ex.
1001, 1:66–2:2. “A flame arrestor is a metal screen that is fitted inside the
neck of the tank and attempts to keep an ignition source such as a flame or
spark from entering the tank of the portable fuel container.” Id. at 2:2–5. A
flame arrestor “absorbs and dissipates the heat generated by [a] flame” and

1 Some of the cited references use the spelling “arrester” rather than
“arrestor.” Except when quoting materials that use a different spelling, we
use the spelling “arrestor” herein in order to be consistent with the
terminology of the challenged ’132 Patent.
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thereby “insures that the vapors on the protected side of the [flame] arrester
barrier do not reach their ignition temperature.” Ex. 1008, 2; see also Pet. 4
(explaining that flame arrestors include “screens with . . . apertures [that]
allow heat to transfer from the flame to the length of the aperture”); Resp. 12
(“A metal flame arrestor . . . is designed to contain enough metal to absorb
the anticipated heat load so that it does not overheat and allow the flame to
pass through it.”)
But flame arrestors also have limitations, particularly when used in
plastic fuel containers. “[P]umping gasoline through a metal screen may
cause a static spark . . . . Metal safety cans offer a grounding tab to prevent
this static electricity discharge, but this is not possible nor practical in a
synthetic resin (plastic) tank . . . .” Ex. 1001, 2:13–17.
D. The ’132 Patent
The ’132 Patent discloses a way of preventing explosions that “run[s]
contrary to conventional thinking.” Ex. 1001, 2:37–38. “Rather than cutting
off a source of liquid fuel or ignition sources” such as by way of a prior art
flame arrestor, the ’132 Patent teaches that “an overly rich fuel-to-air ratio is
provided within the portable fuel container, thus preventing the possibility of
combustion.” Id. at 2:38–42. For example, an overly rich condition may
“be maintained in close proximity to the opening [of the gas container] such
that combustion may not proceed into the interior of the container but rather
any explosive event will be suppressed by the retention of fuel immediately
proximate to the opening.” Id. at 3:16–20.
The ’132 Patent further discloses that one way of maintaining an
overly rich mixture near the opening of a portable gas can is to use a “flash
suppressor.” A flash suppressor can be a cylindrical structure having
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perforations to allow the fuel to pass through, which nevertheless “retain[s] a
sufficient quantity of fuel within the container, and in particular in the
narrowed neck area such that the fuel-air mixture is too rich to support
combustion entering” the portable fuel tank. Id. at 3:41–55.
One type of flash suppressor is depicted in Figure 7 of the ’132
Patent:

Figure 7, reproduced above, depicts an open-topped cylindrical structure 50
(flash suppressor) having many perforations 72. Id. at 6:63–7:42. This
structure is attached to, and resides within, the opening of a portable fuel
container. See, e.g., id. at Fig. 15. In this type of flash suppressor, fuel-
retaining wall 64 at the top of the structure has no perforations, which
prevents all of the fuel from draining from the fuel container, thus
maintaining the fuel-rich environment near the pour spout. Id. at 7:28–31.
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A second type of flash suppressor is depicted in Figure 16 of the ’132
Patent:

Figure 16, reproduced above, depicts flash suppressor 100 having
perforations 102. Id. at 8:37–40. This embodiment has no fuel retaining
wall 64, and instead relies on perforations 102 to retain the fuel at or near the
opening of a portable fuel container. Id. at 8:46–51. “[T]he perforations are
configured in a manner such that after the liquid fuel has been dispensed
from the container and the fuel retention structure is no longer submerged in
the liquid fuel, a quantity of the liquid fuel is retained in the perforations due
to intermolecular forces.” Id. at 8:62–67. This retained fuel creates an
environment near the opening that is too rich to support combustion. Id. at
8:43–46.
E. Challenged Claims
Claims 1–18 are challenged, which are all of the claims of the ’132
patent. Claim 1 is the sole independent claim, and is reproduced below:
1. A fuel container comprising:
a hollow tank body defining a fuel-receiving chamber and a main
container opening for permitting flow of a liquid fuel into and
out of the fuel-receiving chamber;
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a fuel dispensing assembly coupled to the tank body proximate
the main container opening and configured to dispense the
liquid fuel from the container; and
a flash suppressor located proximate the main container opening
and extending at least 2 inches downwardly into the fuel-
receiving chamber,
wherein the flash suppressor comprises a plurality of
perforations through which the liquid fuel is required to flow
in order to dispense the liquid fuel from the container,
wherein the flash suppressor is formed of a synthetic resin
material,
wherein the flash suppressor has an internal volume of at least 2
cubic inches,
wherein the flash suppressor is at least 10 percent open,
wherein the average open area of the perforations is at least 0.001
and not more than 0.05 square inches and wherein the flash
suppressor is not more than 80 percent open; and wherein the
total number of perforations is at least 100 and not more than
10,000 and wherein the average length of the perforations is
at least 0.02 inches.
F. Prior Art and Asserted Grounds
Petitioner asserts the following grounds:
Claims Challenged 35 U.S.C. § References/Basis
1–15 103 Stevick I,2 Stevick II3
16–18 103 Stevick I, Stevick II, Frost4

2 Glen Stevick, David Rondinone, Allan Sagle, and Joseph Zicherman,
Portable Plastic Gasoline Container Explosions and Their Prevention,
Society of Forensic Engineers and Scientists (2010) (Ex. 1005).
3 Glen Stevick, Joseph Zicherman, David Rondinone, and Allan Sagle,
“Failure Analysis and Prevention of Fires and Explosions with Plastic
Gasoline Containers” Journal of Failure Analysis and Prevention, Volume
11, Issue 5, pp. 455–465 (October 2011) (Ex. 1006).
4 U.S. Patent No. 2,850,083, iss. Sept. 2, 1958 (Ex. 1028).
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Petitioner relies on testimony from Mr. Samim Safaei, who has a master’s
degree in fire prevention and work experience in that field. Ex. 1003 ¶¶ 3–4.
Patent Owner relies on testimony from Richard J. Roby, who has work
experience in the field of fire safety, an undergraduate degree in chemical
engineering, and a Ph.D. in mechanical engineering. Ex. 2014 ¶ 3.
II. PATENTABILITY ANALYSIS
A. Claim Construction
“[W]e need only construe terms ‘that are in controversy, and only to
the extent necessary to resolve the controversy.’” Nidec Motor Corp. v.
Zhongshan Broad Ocean Motor Co. Ltd., 868 F.3d 1013, 1017 (Fed. Cir.
2017) (quoting Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc., 200 F.3d 795,
803 (Fed. Cir. 1999)). We find that it is not necessary to adopt explicit
constructions of any claim terms in order to resolve the issues in dispute.
B. Level of Ordinary Skill in the Art
Petitioner asserts that a person of ordinary skill in the art would have
had “at least a bachelor’s degree in engineering or material science, and at
least two years’ industry experience working in the field of explosion
prevention or fuel containers.” Pet. 17 (citing Ex. 1003 ¶¶ 23–26).
Petitioner further asserts, as an alternative, that a person of ordinary skill
could “substitute directly relevant work experience with a higher level of
education, e.g., an advanced degree such as a master’s [of] mechanical
engineering.” Id.
Patent Owner asserts that one of ordinary skill in the art “would have
at least a bachelor’s degree in chemical, mechanical, or fire protection
engineering with some coursework related to fundamentals of combustion
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including an understanding of flammability limits and the structure of
premixed flames.” Resp. 30. Such a person would have “a fundamental
understanding of ignition and extinction of premixed flames” and “at least
two years of industry experience working in the field of combustion design,
fire safety, explosion prevention, or fuel container design.” Id. Patent
Owner agrees that “[a] higher level of education could substitute for work
experience and vice versa.” Id.
The parties’ proposed formulations are similar. For example, both
formulations require at least a bachelor’s degree in a relevant technology and
two years of relevant industry experience, and the parties agree that a higher
level of education could substitute for work experience and vice versa. We
also discern no issues in dispute that turn on differences in the parties’
proposed formulations.
For purposes of this Decision, we apply Petitioner’s formulation of
the level of ordinary skill, but our analysis would have been the same had we
applied Patent Owner’s similar formulation.
C. Analysis of the Stevick I-Stevick II Obviousness Ground
(Claims 1–15)
1. Stevick I
Stevick I is a report on work “undertaken to determine probable
causes of portable plastic gasoline container explosions and to consider and
demonstrate preventive technologies for such explosions.” Ex. 1005, 1. The
report “provides preliminary results” that “clearly show that when gasoline
aging occurs . . .[,] ambient temperature and volume of aged gasoline in the
container are primary variables controlling when such explosions can
occur.” Id. According to Stevick I, aging of gasoline “is a precondition for
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a gasoline container explosion” because “[i]f there is no aging, the
hydrocarbon concentration in the vapor space will be above the upper
explosive limit” (i.e., too rich) “and neither ignition nor explosion can
occur.” Id. at 5.
Stevick I teaches that flame arrestors “work[] by removing heat from
a flame and keeping the temperature of the fuel on the other side of the
arrester below its ignition point.” Ex. 1005, 13. In particular, “[t]he flame
arrester mesh breaks the flame into many flamelets, and the heat of these
flamelets is transferred to the walls of the mesh.” Id.
Stevick I also discloses tests that were performed on flame arrestors,
and indicates that “[n]ot once did an explosion occur.” Ex. 1005, 14. Three
flame arrestor designs are described in the Table 1 of Stevick, which is
reproduced below.

Table 1, above, describes measurements (e.g., mesh hole size and wire
thickness) of the JUSTRITE, EAGLE TYPE 1, and Blitz Commercial flame
arrestors. Id.
2. Stevick II
Stevick II reports additional findings from the work described in
Stevick I. Pet. 26; see also Resp. 26 (“Stevick II reports the same 15 tests
. . . in Stevick I.”) Like Stevick I, Stevick II teaches that flame arrestors
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“work[] by removing heat from a flame,” and that “[t]he flame arrester mesh
breaks the flame into many flamelets, and the heat of these flamelets is
transferred to the walls of the mesh.” Ex. 1006, 8.
Table I of Stevick II, reproduced below, describes six different flame
arrestors. Ex. 1006, 9.

Table 1, above, lists measurements (e.g., mesh hole size and wire thickness)
for these six flame arrestors. Id. Although the manufacturers are not
identified, the first three flame arrestors have exactly the same dimensions as
the three flame arrestors described in Table I of Stevick I.5 Compare Ex.
1006, 9, with Ex. 1005, 14. Thus, it is apparent that the first three flame
arrestors described in Table I of Stevick II (i.e., Manufacturers A, B, and C)
are, the JUSTRITE, EAGLE TYPE 1, and Blitz Commercial flame arrestors,
respectively. Id.

5 Stevick II reports measurements for mesh hole size, critical diameter, and
wire thickness in millimeters, rather than the centimeters used in Stevick I.
Thus, even though the reported dimensions of these measurements differ by
a factor of 10, the actual dimensions of these components are identical.
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3. Claim 1
Independent claim 1 recites a fuel container with a “hollow tank
body,” a “main container opening,” a “fuel dispensing assembly,” and a
“flash suppressor” that “comprises a plurality of perforations” and “is
formed of a synthetic resin material.” Ex. 1001, 11:27–43. The recited flash
suppressor extends “at least 2 inches downwardly” into the container and has
an “internal volume of at least 2 cubic inches.” Id. at 11:35–37, 43–44.
Claim 1 also recites certain additional limitations pertaining to the flash
suppressor and the perforations. Id. at 11:46–53.
Petitioner contends that independent claim 1 would have been obvious
over Stevick I and Stevick II. Pet. 23–40. In particular, Petitioner contends
that one of ordinary skill in the art would have been motivated to take the
metal EAGLE flame arrestor (one of three arrestors described in Stevick I’s
Table 1), replace the metal with plastic, and then increase the thickness of
the wire to match the wire thickness of a plastic flame arrestor described in
Stevick II’s Table 1. Id. at 28–31. According to Petitioner, one of ordinary
skill in the art would have preferred to design a plastic fuel container to
reduce manufacturing costs, and would have started the design process with
the dimensions of a flame arrestor that was known to work with plastic
gasoline containers. Id. at 28–29 (citing Ex. 1003 ¶ 86). Such a person
allegedly would have focused on the EAGLE flame arrestor because it “was
the only flame arrester disclosed in Stevick I implemented in a plastic
gasoline container,” and because it had the largest perforation diameter,
which advantageously would have increased flow rate. Id. (citing Ex. 1003
¶¶ 86–87). Because Stevick I and II are related, such a person allegedly
would have looked to the teachings of both references, realized from Stevick
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II that a plastic flame arrestor could be created, and would have been
motivated to replace the metal of the EAGLE flame arrestor with plastic in
order to reduce the likelihood of electrostatic buildup. Id. at 29–30 (citing
Ex. 1003 ¶ 88–89). According to Petitioner, a plastic flame arrestor would
have been the most practical and low-risk option, and would have been
easier and cheaper to manufacture. Id. at 31 (citing Ex. 1003 ¶¶ 92–93).
Finally, Petitioner contends that such a person would have further modified
the plastic version of the EAGLE flame arrestor by increasing the wire
thickness to match that of the Stevick II plastic flame arrestor, because a
“plastic flame arrester simply would be too fragile if it was made as thin as
its metal counterpart.” Id. at 31 (citing Ex. 1003 ¶ 94).
Patent Owner argues that there are several problems with Petitioner’s
proposed combination and several weaknesses with Petitioner’s rationale for
combining the teachings of Stevick I and II. For example, Patent Owner
argues that the allegedly obvious modified EAGLE flame arrestor would not
extend “at least 2 inches downwardly into the fuel-receiving chamber” as
recited in claim 1. Resp. 43–47. Patent Owner points out that Petitioner
relies on measurements of the JUSTRITE flame arrestor of Stevick I to show
that this limitation is satisfied, even though Petitioner’s obviousness
argument is based on modifying a different embodiment (the EAGLE flame
arrestor). Id. at 43–44. According to Patent Owner, the EAGLE arrestor is
only 1.8 inches long, and thus would not satisfy this limitation. Id. at 45–47.
Having reviewed the evidence and arguments submitted by the parties, we
find Patent Owner’s argument persuasive.
The evidence of record establishes that the EAGLE flame arrestor of
Stevick I and Stevick II is only 1.8 inches in length. We agree with Patent
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Owner’s assertion that the EAGLE flame arrestor described in Table I of
Stevick I (see Ex. 1005, 14) is the same as the Manufacturer B flame arrestor
described in Table I and Figure 10 of Stevick II (see Ex. 1006, 9). See Resp.
45–46; Ex. 2014 ¶¶ 147–148. This argument, and the supporting testimony
from the Roby Declaration, are persuasive at least because both parties
admit that Stevick I and Stevick II describe the same experimental work (see
Pet. 26; Resp. 26), and because the dimensions of the Manufacturer B
arrestor of Stevick II’s Table 1 are identical to the dimensions of the EAGLE
flame arrestor of Stevick I’s Table 1. Compare Ex. 1006, 9, with Ex. 1005,
14; see n.5, supra. The legend of Stevick II’s Figure 10 states that the
Manufacturer B arrestor (i.e., the EAGLE) is “roughly 45 mm deep,” which
translates to 1.8 inches. See Ex. 1006, 9; Ex. 2014 ¶ 147. Moreover, we
agree with Dr. Roby that it is apparent from Stevick II’s Figure 10 that a
portion of this 1.8 inches of depth is positioned in the metal rim, above the
neck of the gasoline container opening. See Ex. 1006, Fig. 10; Ex. 2014
¶ 148. Thus, the length of the EAGLE arrestor that would extend
downwardly into the fuel receiving chamber must be less than 1.8 inches.6
See Ex. 2014 ¶ 148.
Petitioner argues in its Reply that Stevick I teaches that the EAGLE is
“similar in size” to the “3-inch JUSTRITE flame arrestor,” and further
teaches that depths of “1.8 or 3 inches in length were both effective options.”

6 Petitioner’s reply argument that there are “many types of EAGLE flame
arrestors” that have different dimensions (see Reply 5) is not persuasive
because Petitioner relies on a particular EAGLE flame arrestor—the EAGLE
arrestor described in Stevick I and II—as the basis of its obviousness
argument. The dimensions of other types of EAGLE flame arrestors are
irrelevant because those other arrestors are never relied upon in the Petition.
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Reply 5; Ex. 1035 ¶¶ 59–63. But even assuming, arguendo, that the
statement “similar in size to the JUSTRITE device” in Stevick I refers to the
EAGLE arrestor, this generalized description would not overcome the
compelling evidence that the EAGLE arrestor does not extend at least 2
inches downwardly into the fuel receiving chamber (i.e., the actual
dimensions of the EAGLE arrester set forth in Stevick II). The Petition also
never asserts, much less persuasively demonstrates, that any of the proposed
modifications to the EAGLE arrestor would increase the length of the
arrestor so that it satisfies this limitation (see Pet. 23–40).
Petitioner’s new argument on reply that Stevick I teaches that “1.8 or
3 inches in length were both effective options” (see Reply 5) is untimely and
improper. Petitioner was required to identify in its Petition and “with
particularity . . . the grounds on which the challenge to each claim is based,
and the evidence that supports the grounds for the challenge to each claim.”
35 U.S.C. § 312(a)(3) (emphasis added). It is well-established that an
invention “composed of several elements is not proved obvious merely by
demonstrating that each of its elements was, independently, known in the
prior art.” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 418 (2007). Rather,
Petitioner must demonstrate “both ‘that a skilled artisan would have been
motivated to combine the teachings of the prior art references to achieve the
claimed invention, and that the skilled artisan would have had a reasonable
expectation of success in doing so.’” Intelligent Bio-Sys., Inc. v. Illumina
Cambridge Ltd., 821 F.3d 1359, 1367–68 (Fed. Cir. 2016) (citation omitted).
Thus, if a person of ordinary skill in the art would have needed to further
modify the length of the EAGLE arrestor of Stevick I and II in order to
arrive at the invention of claim 1, Petitioner was required to set forth this
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modification with particularity, and provide a supporting rationale, in the
Petition itself.
Here, the Petition contends that modifying the material and wire width
of the EAGLE arrestor would yield the invention of claim 1. The Petition
never proposes lengthening the EAGLE arrestor, much less identifies as a
rationale that one of ordinary skill would have recognized that “1.8 or 3
inches in length were both effective options.” See Reply 5. Petitioner may
not cure these deficiencies in its Petition by proposing additional
modifications or rationales in its Reply. See Patent Trial and Appeal Board
Consolidated Trial Practice Guide (Nov. 2019),7 74 (“[A] reply or sur-reply
may only respond to arguments raised in the preceding brief. . . . ‘Respond’ .
. . does not mean proceed in a new direction with a new approach as
compared to positions taken in a prior filing. . . . [A] reply or sur-reply that
raises a new issue or belatedly presents evidence may not be considered.”).
Accordingly, we reject Petitioner’s attempt to argue on reply that a skilled
artisan would have had reason to further modify the EAGLE arrestor by
increasing its length to three inches.
On this record, and considering all of the evidence and arguments by
the parties, we find Petitioner has failed to demonstrate by a preponderance
of the evidence that Stevick I and Stevick II would have taught or suggested
a fuel container comprising a flash suppressor that extended “at least 2
inches downwardly into the fuel-receiving chamber,” and satisfied the
remaining limitations of claim 1.

7 The Consolidated TPG is available at https://www.uspto.gov/sites/default/
files/documents/tpgnov.pdf.
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We also observe several significant weaknesses in Petitioner’s
rationales for why one of ordinary skill in the art would have had reason to
modify the EAGLE arrestor in the manner set forth in the Petition. As
discussed above, Petitioner contends that an ordinarily skilled artisan would
have wanted to design a portable fuel container out of plastic in order to
reduce costs (Pet. 28–29 (citing Ex. 1003 ¶ 86)), and would have been
motivated to employ a plastic flame arrestor to reduce the likelihood of an
explosion from static build-up (id. at 30 (citing Ex. 1003 ¶ 89)). Petitioner
contends that such a person also would have considered the teachings of
Stevick I and Stevick II together (id. at 29–30 (citing Ex. 1003 ¶ 88–89)),
and that these teachings would have motivated such a person to start with the
EAGLE arrestor because it was “the only flame arrester disclosed in Stevick
I implemented in a plastic gasoline container” (id. at 28 (citing Ex. 1003 ¶
86)) and the flame arrestor with the largest perforation diameter (id. at 28–29
(citing Ex. 1003 ¶¶ 86–87)).
Petitioner’s first rationale, that the EAGLE arrestor is the only
disclosed design implemented in a plastic gasoline container, ignores the
disclosure in Stevick II of three additional flame arrestor designs
implemented with plastic containers, including one arrestor made of plastic.
See Ex. 1006, 9 (Table 1). Petitioner, which asserts that one of ordinary skill
would have considered the teachings of Stevick I and Stevick II together, has
offered no persuasive rationale for why such a person would have ignored
the arrestors disclosed in Stevick II, and focused myopically on a single
arrestor in Stevick I, as the starting point for a design. See Pet 28–31.
Indeed, given the design goals set forth by Petitioner (i.e., a plastic flame
arrestor that would work with a plastic gasoline container), the most logical
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and straightforward approach would have been to start with the plastic flame
arrestor (which had the second largest perforation diameter) that was already
known to work with a plastic fuel container—the Manufacturer D arrestor of
Stevick II. See Ex. 1006, 9 (Table 1).
Petitioner’s argument that the EAGLE arrestor had the largest
perforation diameter is not persuasive because it ignores the modifications
Petitioner proposes to make. It is true that the unmodified EAGLE arrestor
has a hole diameter of 1.43 mm, which is larger than the 1.22 mm hole
diameter of the plastic arrestor of Stevick II. See Ex. 1006, 9 (Table 1,
Manufacturers B and D). But Petitioner proposes increasing the wire
thickness of the EAGLE arrestor from 0.48mm to 0.75mm, a difference of
0.27 mm. See Pet. 31; Ex. 1003 ¶ 170. Assuming no other changes were
made (and Petitioner has proposed none), increasing the wire thickness by
0.27 mm would necessarily decrease the hole diameter of the EAGLE by
0.27 mm.8 Thus, Petitioner’s modified EAGLE arrestor would have a
perforation diameter of 1.16 mm, which is less than the perforation diameter
of Stevick II’s plastic flame arrestor. Accordingly, Petitioner’s rationale
based on the desirability of a large perforation diameter also does not
persuasively demonstrate that one of ordinary skill in the art would have
been motivated to use the metal EAGLE arrestor as the starting point for
designing a plastic flame arrestor.

8 Increasing the wire thickness by 0.27 mm would necessarily decrease the
width of the mesh holes by half of this amount (0.135 mm) on all sides.
This would decrease the total diameter of each hole (i.e., the measurement
from one side to the other) by 0.27 mm.
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We also are not persuaded that one of ordinary skill in the art would
have reasonably expected success in developing a plastic flame arrestor by
taking the dimensions of the metal EAGLE flame arrestor, changing the
material to plastic, and then increasing the wire thickness to match the
thickness of the plastic flame arrestor of Stevick II.
As discussed above, the ’132 Patent discloses preventing explosions
by creating an overly rich fuel/air mixture at the opening of a fuel container.
See, e.g., Ex. 1001, 3:16–20. It was known in the art that combustion could
not occur in the presence of an overly rich fuel/air mixture. See, e.g., id. at
2:43–55; Ex. 1010, 4. But Petitioner has not persuasively shown that it was
known in the prior art to have a flame arrestor that prevents combustion by
creating an overly rich fuel/air mixture at the opening of a fuel container.
The evidence of record demonstrates that prior art flame arrestors
were understood to operate by “absorb[ing] and dissipat[ing] the heat
generated by [a] flame” and thereby “insur[ing] that the vapors on the
protected side of the [flame] arrester barrier do not reach their ignition
temperature.” Ex. 1008, 2; see also Pet. 4 (asserting that flame arrestors
include “screens with . . . apertures [that] allow heat to transfer from the
flame to the length of the aperture”); Resp. 11–12 (“A metal flame arrestor
. . . is designed to contain enough metal to absorb the anticipated heat load
so that it does not overheat and allow the flame to pass through it.”) Indeed,
Stevick I and Stevick II both teach that flame arrestors operate by “removing
heat from a flame,” and that the “flame arrester mesh breaks the flame into
many flamelets, and the heat of these flamelets is transferred to the walls of
the mesh.” Ex. 1005, 13; Ex. 1006, 8. Therefore, one of ordinary skill in the
art would have understood that it was critical to construct a flame arrestor of
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Patent 10,029,132 B2
21
a material that had the ability to efficiently and effectively conduct and
absorb heat.
The “thermal conductivity” of a material is the ability of that material
to conduct heat. See Ex. 2014 ¶ 178. Patent Owner offers persuasive
evidence, which Petitioner never directly disputes, that metals are typically
between 37 and 1,950 times better at conducting heat than are plastics.
See id.
The “thermal inertia” of a material is a measure of how much the
surface temperature of the material will increase when the material absorbs a
given amount of heat (i.e., thermal energy). Ex. 2014 ¶ 177. A material
with a high thermal inertia can absorb a given quantity of thermal energy
while only increasing in temperature by a small amount. See id. In a
material with a low thermal inertia, the same quantity of absorbed heat
would cause a much larger increase in the material’s temperature. See id.
Thus, materials with high thermal inertia are able to absorb much more
energy before reaching a critical temperature (e.g., the combustion
temperature of a fuel/air mixture). See id. Patent Owner offers persuasive
evidence, which Petitioner never directly disputes, that metals typically have
thermal inertias three orders of magnitude greater than plastics (i.e., that a
typical metal could absorb 1,000 times more energy than could a typical
plastic while increasing in temperature by the same amount). See id.
Petitioner proposes to increase the width of the EAGLE arrestor’s
wires as part of its allegedly obvious combination. See Pet. 31. But
Petitioner proposed this change because plastics are weaker than metals. See
id. Petitioner does not contend that this modification would result in a
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Patent 10,029,132 B2
22
plastic flame arrestor with a thermal conductivity or thermal inertia similar
to those of the original, unmodified EAGLE flame arrestor. See id.
Petitioner argues in Reply that the “impact of a material’s thermal
conductivity for quenching is nominal.” Reply 13 (citing Ex. 1035 ¶ 83).
But the cited testimony from the Supplemental Safaei Declaration merely
states that “thermal conductivity is a relative measurement,” that “plastic
still conducts heat,” and that plastic is more thermally conductive than air or
vapors. See Ex. 1035 ¶ 83. Petitioner, however, is not proposing to replace
metal with air, or to replace air with plastic. Petitioner is proposing to
replace the metal of the EAGLE flame arrestor with plastic. Thus, the
relevant comparison is between the thermal conductivity and thermal inertia
of metal, and those of plastic. It is undisputed that metal and plastic are
drastically different in these respects.
Petitioner additionally argues in its Reply that the Gossel equations
used in Stevick II do not depend on thermal conductivity or thermal inertia,
and that Stevick I and Stevick II “do not discuss thermal conductivity as a
consideration in the design of flame arrestors.” Reply 13–14 (citing Ex.
1035 ¶¶ 83–84). But while Stevick I and Stevick II state that a successful
flame arrestor design must satisfy the two Gossel equations, Petitioner has
not persuasively demonstrated that the Gossel equations are the sole
requirements that must be met in order for a flame arrestor to function
properly. Stevick I and Stevick II both explicitly state that a flame arrestor
operates “by removing heat from a flame and keeping the temperature of the
fuel on the other side of the arrester below its ignition point.” Ex. 1005, 13;
Ex. 1006, 8. Accordingly, Stevick I and Stevick II make clear that the
ability of a material to conduct heat away from a flame (i.e., thermal
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Patent 10,029,132 B2
23
conductivity), and to absorb heat while remaining below the ignition
temperature of fuel (i.e., thermal inertia), are critical considerations in flame
arrestor design, regardless of whether those considerations are part of the
two disclosed Gossel equations.
In addition, Petitioner does not offer any evidence that the proposed
modifications to the EAGLE arrestor would result in a design that satisfied
the Gossel equations. For example, the second Gossel equation, used to
calculate the critical velocity (V) of a flame arrestor, is V = (0.38ay)/d2,
where a is the fractional free area of the arrester surface, y is the thickness
of the arrester elements in centimeters, and d is the diameter of the apertures
in centimeters. Ex. 1005, 13–14; Ex. 1006, 8.9 Stevick I and Stevick II
teach that a flame arrestor will not function properly unless its critical
velocity is greater than 0.4 m/s. Ex. 1005, 13; Ex. 1006, 8. The critical
velocity of the unmodified EAGLE arrestor is 0.503 m/s, which is only
slightly greater than the minimum. See Ex. 1005, 14; Ex. 1006, 9.
Increasing the thickness of the wire, as Petitioner proposes, would change
the fractional free area (a), the thickness (y), and the diameter of the
apertures (d), which would change the critical velocity of the arrestor. See
Ex. 1005, 13–14; Ex 1006, 8. Yet Petitioner never calculates the critical
velocity of the modified EAGLE flame arrestor. Thus, even if the modified
EAGLE arrestor would have had sufficient thermal conductivity and thermal
inertia to operate, there would still be no evidence in the record that the

9 The version of this equation in Exhibit 1006 uses the coefficient “38”
instead of “0.38,” because y and d in Exhibit 1006 are measured in meters,
rather than centimeters. These equations, however, are mathematically
equivalent.
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Patent 10,029,132 B2
24
modified EAGLE arrestor would have the minimum necessary critical
velocity.
On this record, we find that metals and plastics differ significantly in
their abilities to conduct and absorb heat. Considering all of the evidence
and arguments put forth by both parties, we are persuaded that an ordinarily
skilled artisan seeking to design a flame arrestor would not have reasonably
expected that taking the design of a metal flame arrestor, and substituting
plastic in place of the metal, and then increasing the wire thickness, would
yield a successful design.
For the foregoing reasons, Petitioner has not demonstrated by a
preponderance of the evidence a sufficient rationale for why one of ordinary
skill in the art would have combined the teachings of Stevick I and Stevick
II in the manner that the Petition contends would have taught or suggested
the limitations of claim 1. Petitioner also has not demonstrated by a
preponderance of the evidence that its allegedly obvious combination of
Stevick I and Stevick II would have taught or suggested a fuel container
comprising a flash suppressor “extending at least 2 inches downwardly into
the fuel-receiving chamber” and satisfying the remaining limitations of
claim 1. Accordingly, for each of these two reasons, Petitioner has not
demonstrated by a preponderance of the evidence that claim 1 is
unpatentable over Stevick I and Stevick II.
4. Claims 2–15
Dependent claims 2–15 depend from claim 1, and thus incorporate the
limitations of claim 1. Petitioner’s contentions regarding claims 2–15 do not
cure the deficiencies discussed above in Petitioner’s contentions regarding
claim 1. Accordingly, for the same reasons discussed above with respect to
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Patent 10,029,132 B2
25
claim 1, Petitioner has not demonstrated by a preponderance of the evidence
that claims 2–15 are unpatentable over Stevick I and Stevick II.
D. Analysis of the Stevick I-Stevick II-Frost Ground
(Claims 16–18)
Claims 16–18 depend from claim 1, and thus incorporate the
limitations of claim 1. Petitioner’s arguments regarding claims 16–18 solely
address the additional limitations recited in these dependent claims, and do
not cure the deficiencies discussed above in Petitioner’s contentions
regarding claim 1. See Pet. 51–56. Accordingly, for the same reasons
discussed above with respect to claim 1, Petitioner has not demonstrated by
a preponderance of the evidence that claims 16–18 are unpatentable over
Stevick I, Stevick II, and Frost.
III. CONCLUSION
For the foregoing reasons, we determine Petitioner has not shown by a
preponderance of the evidence that any of the challenged claims are
unpatentable.
In summary:
Claims 35
U.S.C. §
Reference(s)/Basis Claims
Shown
Unpatentable
Claims Not
Shown
Unpatentable
1–15 103(a) Stevick I, Stevick
II
1–15
16–18 103(a) Stevick I, Stevick
II, Frost
16–18
Overall
Outcome
1–18
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Patent 10,029,132 B2
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IV. ORDER
In view of the foregoing, it is hereby
ORDERED that claims 1–18 of U.S. Patent No. 10,029,132 B2 have
not been shown to be unpatentable; and
FURTHER ORDERED that, because this is a Final Written Decision,
parties to the proceeding seeking judicial review of the decision must
comply with the notice and service requirements of 37 C.F.R. § 90.2.
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Patent 10,029,132 B2
27
For PETITIONER:

Robert Steinberg
Lisa Nguyen
Ashley Finger
LATHAM & WATKINS
bob.steinberg@lw.com
lisa.nguyen@lw.com
ashley.finger@lw.com

For PATENT OWNER:

Robert Evans
Kathleen Markowski Petrillo
Michael Hartley
LEWIS RICE LLC
revans@lewisrice.com
kpetrillo@senniger.com
mhartley@lewisrice.com