Endress + Hauser Conducta Gesellschaft für Mess- und Regeltechnik mbH + Co. KG

Patent Trials and Appeals Board

May 13, 2021

2020003150 (P.T.A.B. May. 13, 2021)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
15/007,827 01/27/2016 Stefan Wilke CD0641-US 9525
140216 7590 05/13/2021
Endress+Hauser, Inc.
PatServe US
2350 Endress Place
Greenwood, IN 46143
EXAMINER
ALLEN, JOSHUA L
ART UNIT PAPER NUMBER
1795
NOTIFICATION DATE DELIVERY MODE
05/13/2021 ELECTRONIC
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
chris.powers@endress.com
lisa.harden@endress.com
patserve.ush@endress.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte STEFAN WILKE, JENS VETTERMANN, JENS
VOIGTLANDER, MAGDALENA LOSIK, and MICHAEL HANKO
Appeal 2020-003150
Application 15/007,827
Technology Center 1700
Before LINDA M. GAUDETTE, JAMES C. HOUSEL, and
CHRISTOPHER C. KENNEDY, Administrative Patent Judges.
GAUDETTE, Administrative Patent Judge.

DECISION ON APPEAL1

The Appellant2 appeals under 35 U.S.C. § 134(a), from the
Examiner’s decision finally rejecting claims 1–8 and 14–16.3

1 The following documents are of record in this appeal: Second Substitute
Specification filed June 18, 2018, as amended (“Spec.”); Final Office Action
dated Jan. 31, 2019 (“Final Act.”); Appeal Brief filed Aug. 30, 2019
(“Appeal Br.”); Examiner’s Answer dated Jan. 22, 2020 (“Ans.”); and Reply
Brief filed Mar. 23, 2020 (“Reply Br.”).
2 “Appellant” refers to “applicant” as defined in 37 C.F.R. § 1.42. The
Appellant identifies the real party in interest as the assignee of record:
Endress + Hauser Conducta Gessellschaft Für Mess- und Regeltechnik
MBH + Co. KG. Appeal Br. 2.
3 We have jurisdiction under 35 U.S.C. § 6(b).
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We REVERSE.
CLAIMED SUBJECT MATTER
The invention relates to a potentiometric sensor. Spec. 1:9. Figure 1,
reproduced below, is a schematic representation of a potentiometric sensor.
Id. at 7:30.
Potentiometric sensor 1, above, comprises measuring half cell 2 and
reference half cell 4, both of which are at least partially immersed in
measuring fluid 3. Id at 8:12–14. Measuring circuit 5 is designed to detect
and create a measuring signal that represents a potential difference between
measuring half cell 2 and reference half cell 4. Id. at 8:15–18. Measuring
half cell 2 may be an ion-selective electrode. Id. at 9:1.
A conventional ion-selective electrode is illustrated in Figure 2,
reproduced below.

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Figure 2 is a schematic representation of prior art ion-selective electrode 6
comprising cylindrical housing 7 that is closed off on its front side by ion-
selective membrane 8, and contains inner electrolyte 9. Spec. 9:16–20.
Electroconductive conductor element 10 is immersed in inner electrolyte 9
and connected to measuring circuit 5 (see Fig. 1). Id. at 9:22–23. “The
conductor element can be identical in design to the reference element of the
reference half cell 4 . . . .” Id. at 9:23–25.
According to the Specification, a drawback of prior art ion-selective
electrodes, such as the one shown in Figure 2, is that substances from
measuring fluid 3 enter into inner electrolyte 9 via membrane 8 and trigger
chemical processes on connector element 10, thereby reducing the
potentiometric sensor’s measurement quality and service life. Spec. 10:9–13.
“Likewise, temperature fluctuations can lead to an impairment of
measurement quality due to silver chloride of the conductor’s element 10
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dissolving and later forming deposits on the back side of the membrane 8.”
Id. at 10:13–16. According to the Specification, the inventive ion-selective
electrode overcomes these drawbacks. See, e.g., id. at 5:5–12.
An embodiment of the inventive ion-selective electrode is illustrated
in Figure 4, reproduced below, id. at 11:17–18. See also id. at 13:28–30 (“A
potentiometric sensor with an ion-selective electrode 20 as described herein
can be designed like the sensor 1 described in Fig. 1. In such a case, the ion-
selective electrode 20 would form the measuring half cell 2.”).

Figure 4 is a schematic representation of an ion-selective electrode 20. Spec.
8:5, 20:17. Ion-selective electrode 20 comprises cylindrical housing 7 that is
closed off on its front side by first ion-selective membrane 8, and contains
first inner electrolyte 9. Id. at 11:25–27. First conductor element 15 is
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immersed in first inner electrolyte 9. Id. at 11:32–33. Conductor element 15
comprises housing 16 that is closed off by gas-tight, second ion-selective
membrane 18, and contains inner conductor 19 immersed in second inner
electrolyte 17. Id. at 11:33–34, 12:6–7, 10–11. Inner conductor 19 can be
connected to measuring circuit 5 (see Fig. 1) of potentiometric sensor 1. Id.
at 12:12–15. Because second membrane 18 functions as a barrier between
second inner electrolyte 17 and first inner electrolyte 9, no silver chloride
deposits can occur on first ion-selective membrane 8’s back side. Id. at
13:12–15. Although silver chloride deposits may occur on second membrane
18’s backside, they cannot adversely impact the measurement quality. Id. at
13:18–20.
Claim 1, reproduced below, is illustrative of the claimed subject
matter:
1. A potentiometric sensor comprising:
a measuring half cell with a conductor element;
a reference half cell with a reference element; and
a measuring circuit connected with the conductor element
of the measuring half cell and the reference element of the
reference half cell, the measuring circuit configured to generate
a measuring signal that is dependent on a potential difference
between the conductor element and the reference element,
wherein the measuring half cell includes a housing in
which a first housing chamber is defined, which is closed by a
first ion-selective membrane, and a first inner electrolyte
contained within the first housing chamber, contacting the first
ion-selective membrane and being contacted by the conductor
element,
wherein the conductor element includes an inner
conductor connected with the measuring circuit and a gas-tight
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barrier that separates the inner conductor from the first inner
electrolyte.
Appeal Br. 11 (Claims App.).
REFERENCES
The Examiner relies on the following prior art:
Name Reference Date
Tomita US 5,310,473 May 10, 1994
Bachas US 5,985,117 Nov. 16, 1999

REJECTION
Claims 1–8 and 14–16 are rejected under 35 U.S.C. § 103 as
unpatentable over Bachas in view of Tomita. Final Act. 2.
OPINION
The Examiner found that Bachas discloses the claim 1 potentiometric
sensor except for “an inner conductor connected with the measuring circuit
and a gas tight barrier that separates the inner conductor from the first inner
electrolyte.” Final Act. 3–4 (quoting claim 1). The Examiner relies on
Tomita for a teaching of this feature. Id. at 4.
Bachas Figure 1 is reproduced below.

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Bachas Figure 1 is “[a] schematic diagram of a potentiometric cell assembly
[(10)] for measuring ion concentrations in a fluid.” Bachas 4:19–20.
Assembly 10 is immersed in solution 16 containing ions of interest. Id. at
4:25–26. Assembly 10 includes ion-selective electrode 12 and external
reference electrode 14 connected to potentiometer 24 for measuring
electromotive force generated between electrodes 12, 14 during
immersion in solution 16. Id. at 4:30–33. Ion-selective electrode 12 is closed
off on one side by ion-selective membrane 30, and includes silver/silver
chloride wire 26 immersed in internal filling solution 28. Id. at 4:34–37.
Tomita Figure 3 is reproduced below.

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Tomita Figure 3 is a partial cut-away view of a compound electrode. Tomita
3:19–20. Tomita’s compound electrode includes glass supporting cylinder 1
containing gelatinized internal solution 9. Id. at 4:18–20. Reference
electrode 8 and inside glass cylinder 2 are positioned in internal solution 9.
Id. at 4:18–22. Responsive glass membrane 3 is formed inside cylinder 2’s
end portion. Id. at 4:4–6. Inside cylinder 2 contains gelatinized internal
solution 6 and internal measurement electrode 5. Id. at 4:11–13.
The Examiner determined that the ordinary artisan would have
replaced Bachas’s “single ‘inner conductor’ Ag/AgCl measuring element”
(silver/silver chloride wire 26) with Tomita’s structure “wherein the
Ag/AgCl measuring element [(5)] is disposed in an inside cylinder [(2)] with
an inside cylinder inner electrolyte [(6)] that separates the Ag/AgCl
measuring element [(5)] from the inner electrolyte [(9)] because Tomita
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discloses that such structure can be used to measure ion concentrations and
serves the same purpose as [Bachas’s] Ag/AgCl electrode [(26)].” Final Act.
4 (internal citation omitted) (citing Tomita 3:63–66 (“The preferred
embodiments of the present invention will be initially described with
reference to an embodiment having an internal solution for an electrode for
measuring ion concentration.”)).
The Appellant argues that the Examiner has not identified sufficient
evidence to support a finding that Bachas’s silver/silver chloride wire 26
serves the same purpose as Tomita’s structure, i.e., inside glass cylinder 2
containing internal solution 6 and electrode 5. See Appeal Br. 7. The
Appellant also argues that the Examiner “provides no reason and no
rationale why one skilled in the art, given two functional measuring
electrodes, would [have been] motivated to replace only the conductor of
one of these measuring electrodes (i.e., the silver/silver chloride wire 26 of
Bachas) with another measuring electrode (i.e., the cited structure of
Tomita).” Id. at 8.
Responsive to the Appellant’s arguments, the Examiner explains that
“the Office’s position [is] that the silver/silver chloride wire 26 of Bachas
and the silver/silver chloride wire 4/5 of Tomita . . . ‘serve the same
purpose’ for measuring ion concentrations.” Ans. 15. The Examiner
contends that replacing
the silver/silver chloride wire of the working half cell of Bachas
with the silver/silver chloride wire of the working half cell of
Tomita (that is housed inside the inner cylinder 2/3) is . . . a
simple substitution that would have the obvious and predictable
outcome of enabling the measurement of ion concentrations.
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Id. at 18; see also Final Act. 4 (“The simple substitution of one known
element for another is likely to be obvious when predictable results are
achieved [MPEP § 2143(8)].”).
As argued by the Appellant, see, e.g., Appeal Br. 8, the Examiner has
not identified sufficient evidence to support a finding that Bachas’s
silver/silver chloride wire 26 and Tomita’s structure “wherein the Ag/AgCl
measuring element is disposed in an inside cylinder with an inside cylinder
inner electrolyte,” were known equivalents, Final Act. 4. See In re Fine, 837
F.2d 1071, 1074 (Fed. Cir. 1988) (reversing the Board’s affirmance of the
Examiner’s rejection under 103: “The Board reiterated the Examiner’s bald
assertion that ‘substitution of one type of detector for another in the system
of Eads would have been within the skill of the art,’ but neither of them
offered any support for or explanation of this conclusion.”). Bachas
describes its invention as “relat[ing] generally to the detection of ions
utilizing ion-selective electrodes,” and “involv[ing] the discovery of a new
group of ionophores which may be used in the ion-selective membranes that
form an essential component of any ion-selective electrode.” Bachas 1:11–
16. Bachas discloses that “internal filling solutions 21 and 28 used in the
reference and ion-selective electrodes, respectively, . . . can be any of those
solutions used in conventional ion-selective electrode systems[, for]
example, . . . 0.01M sodium chloride or 0.01M potassium chloride.” Id. at
4:35–47.
Tomita “relates to an improved ion-measuring device having a
gelatinized member.” Tomita 2:54–55. Tomita discloses that
liquid junction 10 is formed as a part of the gelatinized internal
solution 9 and its surface is maintained under a wet condition,
so that the liquid junction 10 can be repeatedly used without
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cutting off a part thereof. In addition, even though air passes
through the liquid junction 10 into the outside pipe 1 and the
inside cylinder 2, the gelatinized internal solutions 6, 9 are not
dried, so that measurement accuracy can be stabilized and it
becomes unnecessary to further close up the closed portion of
the outside pipe 1 and the inside cylinder 2 tight.
Id. at 4:32–42. Tomita describes the apparatus as “a remarkably compact
thin sheet-type electrode.” Id. at 3:1–2.
The Examiner does not identify, nor do we find any basis in Bachas’s
and Tomita’s disclosures for finding that Tomita’s inside cylinder 2
containing gelatinized internal solution 6 and internal measurement
electrode 5 would operate in substantially the same way to produce
substantially the same result as Bachas’s silver/silver chloride wire 26. See
In re Shaffer, 229 F.2d 476, 479 (CCPA 1956) (“A test of equivalency is
whether the substituted element operates in substantially the same way to
produce substantially the same result as the element replaced.” (citations
omitted)).
In the Answer, the Examiner provides the following additional reason
for replacing Bachas’s wire 26 with inside glass cylinder 2 containing
internal solution 6 and electrode 5: “including an additional ion selective
layer would provide additional benefits to the user as having a second ion-
selective membrane would further limit the transfer of contaminate ions to
the active conductive element and prolong the life of the sensor.” Ans. 19.
We agree with the Appellant that the Examiner has not identified evidence
to support this finding, but relies on improper hindsight reasoning. See Reply
Br. 4.
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In sum, the Appellant has persuaded us of reversible error in the
Examiner’s obviousness rejection. Accordingly, we do not sustain the
rejection of independent claim 1 and its dependent claims 2–8 and 14–16.
DECISION SUMMARY
Claim(s)
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1–8, 14–16 103 Bachas, Tomita 1–8, 14–16

REVERSED