Tennant Co. v. Oxygenator Water Technologies, Inc.

N OTE: This disposition is nonprecedential.
United States Court of Appeals
for the Federal Circuit
______________________
TENNANT CO.,
Appellant
v.
OXYGENATOR WATER TECHNOLOGIES, INC.,
Appellee
______________________
2022-2304
______________________
Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2021-
00625.
______________________
Decided: July 23, 2024
______________________
O LIVER RICHARDS , Fish & Richardson P.C., San Diego,
CA, argued for appellant. Also represented by N ITIKA
G UPTA F IORELLA, D OUGLAS E. M CCANN, J OSEPH B.
WARDEN, Wilmington, DE.
J. D EREK VANDENBURGH , Carlson, Caspers, Vanden-
burgh & Lindquist, P.A., Minneapolis, MN, argued for ap-
pellee. Also represented by N ATHAN D. L OUWAGIE, HANNAH
MOSBY O'BRIEN, AARON W. P EDERSON.
______________________
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 2
Before D YK, REYNA, and STOLL , Circuit Judges.
D YK, Circuit Judge.
Tennant Co. (“Tennant”) appeals from a decision of the
Patent and Trial Appeal Board (“Board”) finding that
claims 13, 14, and 17–27 of U.S. Patent No. RE45,415E (the
“’415 patent”) were not unpatentable as anticipated or ob-
vious. We conclude that substantial evidence supports the
Board’s finding that the claim limitation requiring nano-
bubbles was not shown to be inherent in the prior art by
Tennant’s testing of the prior art or by establishing that
the prior art used the same spacing of the electrodes as the
’415 patent. However, because the Board failed to address
Tennant’s argument that the prior art practiced all the
claimed parameters of the ’415 patent and thus inherently
anticipated the claimed nanobubbles limitation, we reverse
and remand.
BACKGROUND
Oxygenator Water Technologies, Inc. (“OWT”) is the
owner of the ’415 patent. The patent is directed to a
method for oxygenating water by “generat[ing] very small
microbubbles and nanobubbles of oxygen in an aqueous
medium, which bubbles are too small to break the surface
tension of the medium, resulting in a medium supersatu-
rated with oxygen.” ’415 patent, col. 2, l. 67–col. 3, l. 3.
Claim 13 of the ’415 patent is the only independent claim
at issue on appeal, and it provides:
13. A method for producing an oxygenated aqueous
composition comprising:
flowing water at a flow rate no greater than
12 gallons per minute through an electrol-
ysis emitter comprising an electrical power
source electrically connected to an anode
electrode and a cathode electrode contained
in a tubular housing,
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 3
causing electricity to flow from the power
source to the electrodes, and,
producing the composition comprising a
suspension comprising oxygen microbub-
bles and nanobubbles in the water, the mi-
crobubbles and nanobubbles having a
bubble diameter of less than 50 microns,
wherein:
the electrode is separated at a crit-
ical distance from the cathode such
that the critical distance is from
0.005 inches to 0.140 inches;
the power source produces a volt-
age no greater than about 28.3
volts and an amperage no greater
than about 13 amps,
the tubular housing has an inlet
and an outlet and a tubular flow
axis from the inlet to the outlet;
the water flows in the inlet, out the
outlet, is in fluid connection with
the electrodes, and the water flow-
ing into the inlet has a conductivity
produced by the presence of dis-
solved solids such that the water
supports plant or animal life.
’415 patent, col. 11, ll. 20–45.
Tennant petitioned for inter partes review of claims 13,
14, and 17–27 of the ’415 patent alleging anticipation over
two prior art references, U.S. Patent No. 3,891,535
(“Wikey”) and U.S. Patent No. 4,917,782 (“Davies”), and ob-
viousness over either Wikey in combination with other
prior art references or Davies in combination with other
prior art references. The Board first found that
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 4
“[Tennant’s] testing does not sufficiently demonstrate that
Wikey inherently discloses nanobubbles.” J.A. 28. Second,
the Board found that “[Tennant’s] reliance on milkiness
and supersaturation to demonstrate the presence of nano-
bubbles [wa]s also unsupported.” J.A. 28. Third, the Board
found that “the ’415 patent itself does not necessarily
equate a certain critical distance of electrodes with the for-
mation of nanobubbles or microbubbles, to the exclusion of
all other variables.” J.A. 26. For the dependent claims, the
Board found that “[e]very dependent claim challenged . . .
includes the microbubbles and nanobubbles limitation of
claim 13, and, accordingly, [Tennant] does not make its
case as to these dependent claims.” J.A. 31. In summary,
the Board determined that Tennant “ha[d] not shown by a
preponderance of the evidence that claims 13, 14, and 17–
27 of the ’415 patent are unpatentable” as anticipated or
obvious. J.A. 2. Tennant appeals.
We have jurisdiction pursuant to 28 U.S.C.
§ 1295(a)(4)(A).
D ISCUSSION
We first consider the question of anticipation. “Antici-
pation is a question of fact that we review for substantial
evidence.” HTC Corp. v. Cellular Commc’ns Equip., LLC,
877 F.3d 1361, 1368 (Fed. Cir. 2017). Substantial evidence
is “such relevant evidence as a reasonable mind might ac-
cept as adequate to support a conclusion.” Consol. Edison
Co. of New York v. NLRB, 305 U.S. 197, 229 (1938). “A
claim is anticipated if a single prior art reference discloses
all the claimed limitations arranged or combined in the
same way as in the claim.” HTC Corp., 877 F.3d at 1368;
see also 35 U.S.C. § 102. The prior art reference can dis-
close each limitation of the claimed invention either ex-
pressly or inherently. Eli Lilly & Co. v. Los Angeles
Biomedical Rsch. Inst. At Harbor-UCLA Med. Ctr., 849
F.3d 1073, 1074 (Fed. Cir. 2017).
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 5
The Board found that both Wikey and Davies “appear[]
to disclose each limitation of claim 13 except ‘microbubbles
and nanobubbles having a bubble diameter of less than 50
microns.’” J.A. 22, 40–41. Although there seems to have
been no issue as to whether Wikey and Davies disclose mi-
crobubbles, the Board noted that neither Wikey nor Davies
disclosed nanobubbles, which is a requirement of claim 13
of the ’415 patent. The issue is therefore whether Wikey or
Davies discloses the nanobubble limitation. Tennant
makes four distinct arguments in support of its position.
Tennant first contends that its testing of the devices
from Wikey and Davies demonstrates anticipation. Ten-
nant’s expert re-created the device disclosed in Wikey and
tested to see if it produced microbubbles and nanobubbles.
“Microbubble” is defined as “a bubble with a diameter less
than 50 microns.” ’415 patent, col. 4, ll. 10–11. “Nanobub-
ble” is “a bubble with a diameter less than that necessary
to break the surface tension of water,” ’415 patent, col. 4,
ll. 12–13, which Tennant’s expert testified was “[r]oughly
100 nanometers” (0.1 microns), J.A. 6048. The expert used
an imaging tool which showed that the Wikey device cre-
ated microbubbles. Likewise, the expert re-created the de-
vice from Davies, and testing showed that it also produced
microbubbles. However, Tennant’s expert admitted “that
none of the testing [he] performed determined whether or
not there were nanobubbles in the water.” J.A. 6049, 70:1–
3. The Board did not err in concluding that the testing did
not detect the presence of nanobubbles.
Second, Tennant argues that even if the testing did not
directly detect nanobubbles, it demonstrated that the wa-
ter was supersaturated, and that this was sufficient to
show the presence of nanobubbles. Tennant points to the
specification of the ’415 patent which describes “an oxygen
emitter which . . . generates very small microbubbles and
nanobubbles of oxygen in an aqueous medium, which bub-
bles are too small to break the surface tension of the me-
dium, resulting in a medium supersaturated with oxygen.”
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 6
’415 patent, col. 2, l. 66–col. 3, l. 3. Tennant contends that
“the presence of nanobubbles was tested according to the
only parameters provided by the ’415 patent (i.e. that they
supersaturate water, see [J.A.] 73 at 4:12–15).” Appellant’s
Opening Br. at 35. However, the ’415 patent defines “nano-
bubble” as “a bubble with a diameter less than that neces-
sary to break the surface tension of water. Nanobubbles
remain suspended in the water, giving the water an opal-
escent or milky appearance.” ’415 patent, col. 4, ll. 12–15.
The specification describes that nanobubbles result in
supersaturation, but Tennant has not shown that the re-
verse is true. The Board found that supersaturation does
not show the presence of nanobubbles. The Board’s deci-
sion is supported by substantial evidence. Tennant’s ex-
pert admitted that “dissolved oxygen” does not “tell us
anything about the size of the bubbles that are in the wa-
ter.” J.A. 6050, 76:9–14. Additionally, Tennant presents
no evidence that the water it tested had a milky appear-
ance or that supersaturation gives the water a milky ap-
pearance. Tennant’s tests of Wikey and Davies showed
that the “[v]ast majority of bubbles disappear[ed] within 1
minute” and “no bubbles [were] visible after 3 hours.” J.A.
6548, 6556, 6562. The specification provides that “[the de-
vice] forms bubbles which are too small to break the surface
tension of the fluid. These bubbles remain suspended in-
definitely in the fluid and, when allowed to build up, make
the fluid opalescent or milky. Only after several hours
do[es] . . . the water clear[].” A’415 patent, col.4, ll. 32–37.
Thus, Tennant failed to show that supersaturation demon-
strated the existence of nanobubbles.
Third, Tennant argues that both Wikey and Davies in-
herently produce microbubbles and nanobubbles because
they both “describe[] an anode and cathode spaced at the
‘critical distance,’ and given the ’415 patent’s teachings
that the ‘critical distance’ is the critical factor in the crea-
tion of microbubbles and nanobubbles, the Board should
have found Wikey [and Davies] inherently anticipate[] the
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 7
bubble size limitation.” Appellant’s Opening Br. at 34; see
also Appellant’s Opening Br. at 47. Tennant relies on the
’415 patent’s abstract which states that “[w]hen the anode
and cathode are separated by a critical distance, very small
microbubbles and nanobubbles of oxygen are generated.”
J.A. 62.
The Board found “that the ’415 patent itself does not
necessarily equate a certain critical distance of electrodes
with the formation of nanobubbles or microbubbles, to the
exclusion of all other variables.” J.A. 26. The Board’s find-
ing is supported by substantial evidence. Tennant’s expert,
Dr. Tremblay, testified that “a person of skill in the art
reading the ’415 patent would understand . . . that many
things other than spacing of the electrodes are going to
have an effect on the bubble size created using devices de-
scribed in the patent.” J.A. 6039, 30:24–31:5.
Finally, Tennant argues that Wikey and Davies “met
all of the limitations of independent claim 13 as they relate
to the parameters of the device—i.e., the voltage used, the
amperage used, the shape of the housing, the inlet, the out-
let, the fluid flow, and even the ‘critical distance.’” Appel-
lant’s Opening Br. at 33. The Board found that both Wikey
and Davies “appear[] to disclose each limitation of claim 13
except ‘microbubbles and nanobubbles having a bubble di-
ameter of less than 50 microns.’” J.A. 22, 40–41. And, Ten-
nant argues, “when all claimed parameters are present—
as in Wikey—microbubbles and nanobubbles are inher-
ently formed.”1 Appellant’s Reply Br. at 7. For support,
1 OWT contends that parameters other than those
found in the claim limitations affects the production of mi-
crobubbles and nanobubbles. This appears to contradict
OWT’s representations made during prosecution of the ’415
patent. And even if other parameters affect bubble size,
nothing in the specification discloses any such requirement
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 8
Tennant points to In re King, which holds that “if a previ-
ously patented device, in its normal and usual operation,
will perform the function which an appellant claims in a
subsequent application . . . then such application . . . will
be considered to have been anticipated by the former pa-
tented device.” 801 F.2d 1324, 1326 (Fed. Cir. 1986); see
also In re Ackenbach, 45 F.2d 437, 439 (C.C.P.A. 1930).
Tennant made this same argument to the Board in its
IPR petition, contending that “[t]he Wikey emitter has the
same configuration as claim 12 and therefore produces the
same result – namely, a suspension comprising microbub-
bles and nanobubbles.” J.A. 121–22; see also J.A. 24–25
(The Board noting that “[Tennant] also replies that claim
13 specifies voltage, current, and flow rate limits that, com-
bined with the critical distance, create microbubbles and
nanobubbles, and that Wikey teaches values for each of
these variables falling within the claimed ranges”); J.A.
112 (“Wikey discloses a tubular water electrolysis emitter
having an anode separated from a cathode by the claimed
critical distance in combination with the claimed voltage,
amperage and flow rate. The Wikey emitter therefore pro-
duces a suspension comprising microbubbles and nanobub-
bles in the water, as the ’415 patent acknowledges.”).
Tennant’s expert testified that “Wikey not only dis-
closes the claimed anode and cathode separation distance
in combination with the claimed voltage, it inherently pro-
vides the claimed current and flow rates,” J.A. 528, and
“Davies not only discloses the anode and cathode separa-
tion distance in combination with the claimed voltage and
flow rate of the ’415 patent, it also inherently provides the
claimed current,” J.A. 559. However, the Board did not ad-
dress this argument, finding only that Wikey’s and Davies’
or describes how to manipulate those parameters to pro-
duce microbubbles and nanobubbles.
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 9
disclosure of the “critical distance” was insufficient to in-
herently disclose production of nanobubbles.
The Board’s error is particularly significant given the
prosecution history where OWT represented that mi-
crobubbles and nanobubbles were inherently produced
when the claim parameters of the ’415 patent were fol-
lowed. The examiner rejected “[c]laims 2, 3, 5, 7, 9, 10, 13–
17, 21, 22, 26, 27, 29–32, 35, and 39–42 . . . as being antic-
ipated by Murrell U.S. Patent 5,049,252.” Tennant Co. v.
Oxygenator Water Techs., Inc., IPR2021-00625, Exhibit
1102 at 216 (PTAB Mar. 9, 2021). OWT cancelled claims
13–49 in favor of new claims 50–67. New claim 55, which,
as amended, became claim 13 in the ’145 patent, provided
that “the combination of the critical distance, the voltage,
amperage and the water conductivity results in the for-
mation of a suspension comprising oxygen nanobubbles in
the water.” Tennant, IPR2021-00625, Exhibit 1102 at
190.2 In defending claim 55 against anticipation by Mur-
rell, OWT submitted:
The new claims are directed to . . . a method of pro-
ducing the suspension of nanobubbles in water . . .
[h]ence, the water and microbubbles/nanobubbles
of oxygen suspended in the water are positively re-
cited features of a system, a method and a suspen-
sion. In addition, the voltage, amperage, the
separation of the electrode spacing, and the total
solids in the water signifying viscosity and
2 That language was ultimately deleted from claim
13, but there was no suggestion that the change was sub-
stantive. The patent examiner had accepted claim 55 (ex-
cept for a defective reissue oath, Tennant, IPR2021-00625,
Exhibit 1102 at 167), and Tennant deleted the language af-
ter the acceptance. Tennant, IPR2021-00625, Exhibit 1102
at 140–141. Tennant provided no explanation for the dele-
tion. See id. at 136–153.
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 10
conductivity of the water, which can be summed by
the phrase tap water, are positively recited fea-
tures of this system. These features achieve the
suspension of nanobubbles in water.
Id. at 196. Additionally, OWT stated that its “system,
method and suspension” was different than Murrell’s be-
cause its “micro and nanobubbles do not rise to the surface
[i.e., they remain suspended in the water] . . . [OWT’s]
claims now recite the conditions needed to produce [mi-
crobubbles and nanobubbles], including voltage, amperage,
total water solids indicating conductivity, and the electrode
spacing.” Id. at 198.
In other words, if the physical parameters of the claim
were followed, it would automatically produce nanobub-
bles. OWT cannot make one argument when seeking issu-
ance of its patent and the opposite argument in defending
the patent in post-grant review and to this court. “[J]udi-
cial estoppel[] ‘generally prevents a party from prevailing
in one phase of a case on an argument and then relying on
a contradictory argument to prevail in another phase.’”
New Hampshire v. Maine, 532 U.S. 742, 749 (2001) (quot-
ing Pegram v. Herdrich, 530 U.S. 211, 227 n.8 (2000)); see
also Trustees in Bankr. Of N. Am. Rubber Thread Co. v.
United States, 593 F.3d 1346, 1354 (Fed. Cir. 2010) (“Judi-
cial estoppel applies just as much when one of the tribunals
is an administrative agency as it does when both tribunals
are courts.”); Tyler Refrigeration v. Kysor Indus. Corp., 777
F.2d 687, 690 (Fed. Cir. 1985) (holding that the district
court properly treated the Aokage reference as prior art
“[i]n view of [patent owner’s] explicit admission” “before
the PTO during the prosecution of the [patent]” that “the
Aokage reference [was] prior art”); In re Nomiya, 509 F.2d
566, 570–71 (C.C.P.A. 1975) (holding that while “[a]ppel-
lants’ brief now questions the PTO’s use of Figs. 1 and 2 of
their application as ‘prior art’ . . . arguing that there is no
statutory basis for considering Figs. 1 and 2 to be ‘prior art’
. . . [b]y filing an application containing Figs. 1 and 2,
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TENNANT CO. v. OXYGENATOR WATER TECHNOLOGIES, INC. 11
labeled prior art . . . appellants have conceded what is to be
considered as prior art in determining obviousness of their
improvement.”).
CONCLUSION
Because the Board failed to address Tennant’s argu-
ment that Wikey and Davies disclosed all the parameters
of the ’415 and therefore inherently produce microbubbles
and nanobubbles, we vacate and remand. Because we va-
cate and remand to the Board to consider Tennant’s antic-
ipation argument, we do not reach Tennant’s obviousness
arguments (which depends on its contention that either
Wikey or Davies produce nanobubbles).
VACATED AND REMANDED
COSTS
No Costs.
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