Ex Parte Alfes

Patent Trial and Appeal Board

Sep 7, 2017

13263887 (P.T.A.B. Sep. 7, 2017)

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.
13/263,887 12/22/2011 Ludger Alfes 2009P05883WOUS 4611
22116 7590 09/11/2017
SIEMENS CORPORATION
INTELLECTUAL PROPERTY DEPARTMENT
3501 Quadrangle Blvd Ste 230
EXAMINER
SEHN, MICHAEL L
Orlando, EL 32817 ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
09/11/2017 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):
IPDadmin.us@siemens.com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte LUDGER ALFES
Appeal 2016-003891
Application 13/263,887
Technology Center 3700
Before CHARLES N. GREENHUT, THOMAS F. SMEGAL, and
GORDON D. KINDER, Administrative Patent Judges.
SMEGAL, Administrative Patent Judge.
DECISION ON APPEAL
STATEMENT OF THE CASE
Ludger Alfes (Appellant)1 seeks our review under 35 U.S.C. § 134 of
the Examiner’s rejection2 under 35 U.S.C. § 103(a) of claims 9-11, 15, and
16 as unpatentable over Denis (US 3,909,012, iss. Sept. 30, 1975), Nogiwa
(US 6,802,689 B2, iss. Oct. 12, 2004), and Schmohl (US 5,412,977, iss.
May 9, 1995).3 We have jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.
1 According to Appellant, the real party in interest is Siemens
Aktiengesellschaft. Appeal Br. 3.
2 Appeal is taken from the adverse decision of the Examiner as set forth in
the Final Office Action, dated June 9, 2015 (“Final Act.”).
3 Claims 1—8 and 12—14 have been cancelled.
Appeal 2016-003891
Application 13/263,887
CLAIMED SUBJECT MATTER
Claim 9, the sole independent claim, is reproduced below and
illustrates the claimed subject matter, with disputed limitations emphasized.
9. A multistage turbocompressor for compressing a
process gas from an inlet pressure at an inlet of a first stage of
the turbocompressor to a discharge pressure at an exit of a last
stage of the turbocompressor, the turbocompressor comprising:
at least one rotor having a rotor shaft;
at least one casing;
at least one gas seal associated in each case with at least
the first stage and the last stage for sealing a penetration of the
rotor shaft through a wall of the at least one casing, against a
respective stage inlet pressure or stage discharge pressure,
wherein the gas seals are connected to at least one sealing gas
line via which they are supplied with a sealing gas;
wherein at least one pressure chamber on a pressure side
of the at least one gas seal of the last stage which provides sealing
against pressure discharge to the environment is connected to at
least one relief line which opens into a pressure sink,
wherein a plurality of sealing gas lines are connected to a
sealing gas feed line in which at least one control valve is
arranged between junctions of different sealing gas lines,
wherein a gas seal is provided at a plurality of stages and
the respectively associated sealing gas line has a respective
throttle which adjusts the sealing gas pressure to the sealing
pressure, and
wherein the control valve is arranged upstream of the
sealing gas line, and wherein a control unit is provided which is
designed in such a way that when a first volumetric-flow limit
value offlow through the sealing gas line of at least one gas seal
is fallen short of as a result of the respective throttle, the control
valve in the sealing gas feed line opens,
wherein a further control valve is provided in the relief
line, the further control valve being controlled by said control
unit, said control unit being designed in such a way that the
further control valve in the relief line opens if a second
volumetric-flow limit value is fallen short of
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Appeal 2016-003891
Application 13/263,887
ANALYSIS
Obviousness of Claims 9—11, 15, and 16 over Denis, Nogiwa, and
Schmohl
Appellant argues claims 9—11, 15, and 16 together in contesting the
rejection of these claims as obvious over Denis, Nogiwa, and Schmohl. See
Appeal Br. 6—8; Reply Br. 2—3. We select claim 9 as the representative
claim for this group, and the remaining claims stand or fall with claim 9. 37
C.F.R. §41.37(c)(l)(iv).
In rejecting claim 9, the Examiner relies on Denis for teaching a
multistage turbocompressor, including, inter alia, a sealing gas feed line, but
states that Denis
fails to disclose the sealing gas feed line having at least one
control valve being arranged between junctions of different
sealing gas lines, wherein the control valve is arranged upstream
of the sealing gas line and a control unit is provided which is
designed in such a way that when a first volumetric flow limit
value of flow through the sealing gas line of at least one gas seal
is fallen short of as a result of the respective throttle, the control
valve opens, and wherein a further control valve is provided in
the relief line, the further control valve being controlled by said
control unit, said control unit being designed in such a way that
the further control valve in the relief line opens [if] a second-
volumetric-flow limit value is fallen short of.
Final Act. 3^4.
The Examiner finds, however, that Nogiwa teaches a multistage
turbocompressor having gas seals with sealing gas feed lines with control
valves and a control unit, where the “control valve opens when a first
volumetric flow limit value, as detected by the control unit, is fallen short
of.” Id. at 4 (citing Nogiwa, col. 5,11. 29-36). The Examiner explains that
when “[ljeakage occurs in the purge gas line (24),” then “the flow rate of
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Appeal 2016-003891
Application 13/263,887
purge gas must be increased via the control valve in order to maintain the
pressure in the purge gas line.” Id.
From the foregoing, the Examiner determines that it would
have been obvious
to make the sealing gas feed lines of Denis with control valves
and a control unit, as taught by Nogiwa, and arrange the control
valves upstream and between junctions of different sealing gas
lines for the purpose of controlling the flow, and thus the
pressure, of gas into the gas seal. This will ensure a proper seal
between respective stages of the turbocompressor.
Id.
The Examiner also finds that Schmohl teaches a turbocompressor with
gas seals and a relief line having “a control valve (13) controlled by a
control unit (14),” which “is designed so that the control valve opens if a
volumetric-flow limit value is fallen short of.” Id. (citing Schmohl, col. 3,11.
57—64). The Examiner concludes that it would have been obvious “to make
the relief line of Denis with a further control valve controlled by a control
unit, as taught by Schmohl, for the purpose of preventing the buildup of
sealing gas within the seal, which would possibly increase the pressure past
a desirable amount and in turn could cause damage to the compressor.” Id.
Without referring to any specific limitation of claim 9, Appellant first
contends that “Nogiwa literally suggests that the pressure in the seal gas line
entering the seal is kept constant by the control,” and that “[t]his teaching is
contrary to the claimed invention which maintains a minimum flow value
through the seal gas line independent of the seal gas pressure in the seal gas
line.” Appeal Br. 6; Reply Br. 3. However, Appellant’s contention is
unavailing as it is not commensurate with the scope of claim 9, which is not
limited to maintaining a minimum flow value, but merely recites a “further
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Appeal 2016-003891
Application 13/263,887
control valve in the relief line” that “opens if a second volumetric-flow limit
value is fallen short of.” Appeal Br. 10, Claims App. As we are instructed
by our reviewing court, “limitations are not to be read into the claims from
the [Specification.” In re Van Geuns, 988 F.2d 1181, 1184 (Fed. Cir. 1993)
(citing In reZletz, 893 F.2d 319, 321 (Fed. Cir. 1989)).
Furthermore, the Examiner explains that while “Nogiwa does teach an
increase in leakage via the seal surface and a corresponding increase in
purge gas flowing into the purge gas line in order to keep the pressure in the
purge gas line constant,” that “this corresponding increase in the flow of
purge gas occurs because a volumetric flow limit value was fallen short of. .
. and because of this, the amount of purge gas flowing into the purge gas line
via the control valve needs to increase in order to keep the pressure in the
purge gas line constant.” Ans. 2—3. Based on the foregoing, the Examiner
concludes that “Nogiwa does teach a volumetric flow limit value of flow
being fallen short of, and this falling short results in the increase in purge gas
flowing to the purge gas line that the Appellant references.” Id. at 3.
Appellant also contends that Claim 9 “provides that the seal gas
pressure is released into a release line to still maintain the required minimum
flow,” and that “Nogiwa exactly teaches the opposite.” Appeal Br. 6.
Again, Appellant’s contention is unavailing as it is not commensurate with
the scope of claim 9, which is not limited to maintaining a “required
minimum flow” but merely recites “the further control valve in the relief line
that opens if a second volumetric-flow limit value is fallen short of.” Appeal
Br. 10, Claims App. See In re Van Geuns, 988 F.2d at 1184.
Appellant continues by contending that “[sjince Schmohl also only
deals with the possibility of a defect of one of the two dry gas seals
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Appeal 2016-003891
Application 13/263,887
(basically, only with the primary dry gas seal) the teaching or suggestion of
avoiding damage to the dry gas seals during unusual operating conditions,
for example with nearly no pressure difference, is not evident in Schmohl, as
well.” Appeal Br. 7. However, Appellant is simply attacking Schmohl in
isolation for lacking support for teaching for which it was not cited.
Nonobviousness cannot be established by attacking references individually
when the rejection is predicated upon a combination of prior art disclosures.
See In re Merck & Co., 800 F.2d 1091, 1097 (Fed. Cir. 1986). As the
Examiner explains, “the teaching [of Schmohl] is directed only towards
modifying the single dry gas seal of Denis with a control valve in the relief
line.. .thus avoiding the increase in pressure past a desirable amount in the
seal,” and thus “avoiding possible damage to the seal and the compressor.”
Ans. 3^4. Appellant has not disputed these findings.
Again without referring to any specific limitation of claim 9,
Appellant contends “the claimed invention doesn't deal with reacting to any
damage of any of the two dry gas seals, but deals with avoiding any damage
of the dry gas seals,” and that “[s]ince none of the documents cited deals
with avoiding damage of the dry gas seals during abnormal operating
conditions, none of the cited documents is able to teach a person with
ordinary skill in the art the features of the claimed invention in an obvious
manner.” Appeal Br. 7—8. (emphasis added). Again, Appellant’s contention
is unavailing as it is not commensurate with the scope of claim 9, which is
not limited to avoiding damage to dry gas seals in abnormal operating
conditions, but merely recites control valves that open if “a volumetric-flow
limit value is fallen short of.” Appeal Br. 10, Claims App. See In re Van
Geuns, 988 F.2d at 1184.
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Appeal 2016-003891
Application 13/263,887
For the foregoing reasons, we discern no error in the Examiner’s
findings and sustain the Examiner’s unpatentability rejection of claims 9—11,
15, and 16 as obvious over Denis, Nogiwa, and Schmohl.
DECISION
We AFFIRM the Examiner’s rejection.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a). See 37 C.F.R. §
1.136(a)(l)(iv).
AFFIRMED
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