Siva Sivakumaran et al.

Patent Trials and Appeals Board

Dec 31, 2019

12940497 - (D) (P.T.A.B. Dec. 31, 2019)

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.
12/940,497 11/05/2010 Siva Sivakumaran 0087748-000016 7622
135838 7590 12/31/2019
Studio Torta (RINGFENCE)
c/o BUCHANAN INGERSOLL & ROONEY PC
P.O. BOX 1404
ALEXANDRIA, VA 22313
EXAMINER
WHITE, DWAYNE J
ART UNIT PAPER NUMBER
3745
NOTIFICATION DATE DELIVERY MODE
12/31/2019 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):
ADIPDOC1@BIPC.COM
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
____________

Ex parte SIVA SIVAKUMARAN and GEIR LEIVSETH

Appeal 2018-002361
Application 12/940,497
Technology Center 3700
____________

Before MICHAEL C. ASTORINO, PHILIP J. HOFFMANN, and
ROBERT J. SILVERMAN, Administrative Patent Judges.

SILVERMAN, Administrative Patent Judge.

DECISION ON APPEAL

STATEMENT OF THE CASE
Pursuant to 35 U.S.C. § 134(a), Appellant1 appeals from the
Examiner’s decision rejecting claims 1, 4, 6, 7, and 9–11. We have
jurisdiction under 35 U.S.C. § 6(b).
We AFFIRM.

1 We use the word “Appellant” to refer to “applicant” as defined in
37 C.F.R. § 1.42. Appellant identifies “ANSALDO ENERGIA
SWITZERLAND AG” as the real party in interest. Appeal Br. 2.
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ILLUSTRATIVE CLAIM
1. A leaf seal located between a higher pressure region
and a lower pressure region of a rotary machine, the leaf seal
comprising:
an annular housing having an upstream side-cheek and a
downstream side-cheek; and
an annular array of resilient leaves arranged between the
upstream side-cheek and the downstream side-cheek for
forming a seal between a static structure and a rotating
component of the machine, the leaves extending from the
housing in a first direction that is offset from a radial direction
in a second direction of rotation of the rotating component, each
leaf having
a radially outer end held within the housing,
a radially inner free end,
an upstream edge adjacent to an inner surface of
the upstream side-cheek, and
a downstream edge adjacent to an inner surface of
the downstream side-cheek;
wherein at least one of (a) the inner surface of the
upstream side-cheek is parallel to the inner surface of the
downstream side-cheek, (b) the inner surface of the upstream
side-cheek is parallel to the upstream edges of the leaves, and
(c) the inner surface of the downstream side-cheek is parallel to
the downstream edges of the leaves;
wherein the upstream side-cheek and the downstream
side-cheek each extend in the first direction between
corresponding first and second ends of the upstream and
downstream side-cheeks, respectively, the first end being
proximal to the housing and the second end being opposite to
the first end and distal from the housing;
wherein the upstream edges of the leaves and the
adjacent upstream side-cheek define an upstream gap
therebetween, and the downstream edges of the leaves and the
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adjacent downstream side-cheek define a downstream gap
therebetween;
wherein the upstream gap includes a first upstream gap
portion proximate to the first end of the upstream side-cheek,
and a second upstream gap portion proximate to the second end
of the upstream side-cheek;
wherein the downstream gap includes a first downstream
gap portion proximate to the first end of the downstream side-
cheek, and a second downstream gap portion proximate to the
second end of the downstream side-cheek;
wherein at least one of the inner surface of the upstream
side-cheek and the inner surface of the downstream side-cheek
is a frustoconical surface that is angled relative to the radial
direction so that an apex of the cone is further towards the
higher pressure region of the rotary machine than the base of
the cone;
wherein the leaf edges adjacent each side-cheek inner
surface define a respective similarly-oriented frustocone,
wherein:
(i) if the free end of at least one of the leafs moves in the
radially outward direction, the upstream gap decreases if the
upstream side-cheek inner surface and the adjacent leaf edge
are frustoconical, thereby increasing aerodynamic blow-up
forces acting on the leaves, and the downstream gap increases if
the downstream side-cheek inner surface and the adjacent leaf
edge are frustoconical, thereby decreasing the aerodynamic
blow-down forces acting on the leaves; and
(ii) if the free end of at least one of the leafs moves in the
radially inward direction, the upstream gap increases if the
upstream side-cheek inner surface and the adjacent leaf edge
are frustoconical, thereby decreasing the aerodynamic blow-up
forces acting on the leaves, and the downstream gap decreases
if the downstream side-cheek inner surface and the adjacent leaf
edge are frustoconical, thereby increasing the aerodynamic
blow-down forces acting on the leaves; and
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wherein (i) if the free end of the at least one of the leafs
moves in the radially outward direction, the first upstream gap
portion of the at least one of the leafs decreases less than the
second upstream gap portion of the at least one of the leafs, and
the first downstream gap portion of the at least one of the leafs
increases less than the second downstream gap portion of the at
least one of the leafs; and
wherein (ii) if the free end of at least one of the leafs
moves in the radially inward direction, the first upstream gap
portion of the at least one of the leafs increases less than the
second upstream gap portion of the at least one of the leafs, and
the first downstream gap portion of the at least one of the leafs
decreases less than the second downstream gap portion of the at
least one of the leafs.
REFERENCES
Name Reference Date
Grondahl US 2004/0150165 A1 Aug. 5, 2004
Awtar et al. (“Awtar”) US 2008/0272553 A1 Nov. 6, 2008

REJECTION
Claims 1, 4, 6, 7, and 9–11 are rejected under 35 U.S.C. § 103(a) as
unpatentable over Grondahl and Awtar.
FINDINGS OF FACT
The findings of fact relied upon, which are supported by a
preponderance of the evidence, appear in the following Analysis.
ANALYSIS
Independent Claim 1
The Appellant contends that Grondahl fails to teach or suggest the two
“wherein” clauses that conclude claim 1:
wherein (i) if the free end of the at least one of the leafs
moves in the radially outward direction, the first upstream gap
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portion of the at least one of the leafs decreases less than the
second upstream gap portion of the at least one of the leafs, and
the first downstream gap portion of the at least one of the leafs
increases less than the second downstream gap portion of the at
least one of the leafs; and
wherein (ii) if the free end of at least one of the leafs
moves in the radially inward direction, the first upstream gap
portion of the at least one of the leafs increases less than the
second upstream gap portion of the at least one of the leafs, and
the first downstream gap portion of the at least one of the leafs
decreases less than the second downstream gap portion of the at
least one of the leafs.
See Appeal Br. 11–16.
The Appellant (see Appeal Br. 16, Reply Br. 5–6) and the Examiner
(see Answer 2, 4–5) agree that the changed disposition of Grondahl’s “leaf
seal members 24” having “a free end or portion 30,” from Figure 2B to
Figure 2C of Grondahl, illustrates the movement of such elements in a
“radially outward direction” (per the first “wherein” clause of claim 1). The
Appellant (see Appeal Br. 16; Reply Br. 5) and the Examiner (see Answer 4)
further agree that relevant features are properly identified in the Appellant’s
annotated version of Figures 21B and 21C, which is reproduced below:

The foregoing version of Grondahl’s Figures 21B and 21C, as annotated by
the Appellant, show the portions of the depicted embodiment that
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correspond to the identified claim limitations, with the leaves in a “radially
inward” position (Fig. 21B) and a “radially outward” position (Fig. 21C).
With regard to the first part of the first “wherein” clause, claim 1
states: “if the free end of the at least one of the leafs moves in the radially
outward direction, the first upstream gap portion of the at least one of the
leafs decreases less than the second upstream gap portion of the at least one
of the leafs.”
As seen in Figures 21B and 21C, above, the deflections of the free
ends of Grondahl’s leaves are larger, proximate their tips, than proximate
their “fixed portion[s] 328” (see Grondahl ¶ 72). Accordingly, in
Grondahl’s Figures 21B and 21C, in “radially outward” movement, the “first
upstream gap portion” of the free end of a leaf (being more proximate the
fixed end thereof) decreases less than the “second upstream gap portion” of
the free end of the leaf (the latter being more proximate the tip thereof).
This is what the first part of the first “wherein” clause of claim 1 recites.
Turning to the second part of the first “wherein” clause, and applying
the same condition (i.e., “if the free end of the at least one of the leafs moves
in the radially outward direction”), the claim states: “the first downstream
gap portion of the at least one of the leafs increases less than the second
downstream gap portion of the at least one of the leafs.” In view of the
behavior of the portions of the Grondahl leaf, as indicated by Figures 21B
and 21C, Grondahl’s “first downstream gap portion” (being more proximate
the fixed end) increases less than the “second downstream gap portion”
(being less proximate the fixed end). Again, this behavior is what the
identified limitation of claim 1 requires.
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We now turn to the second “wherein” clause of claim 1:
wherein (ii) if the free end of at least one of the leafs
moves in the radially inward direction, the first upstream gap
portion of the at least one of the leafs increases less than the
second upstream gap portion of the at least one of the leafs, and
the first downstream gap portion of the at least one of the leafs
decreases less than the second downstream gap portion of the at
least one of the leafs.
The Examiner agrees that “the [Appellant] has correctly identified that a
transition from Grondahl figure 21A to 21B corresponds to wherein clause[ ]
‘ii’ in claim 1,” i.e., the circumstance of a leaf that moves “radially inward.”
Answer 2. Figures 21A and 21B of Grondahl are presented below:

Grondahl’s Figures 21A and 21B depict the embodiment with leaves in what
the Appellant and the Examiner regard as a “radially outward” position
(Fig. 21A) and “radially inward” position (Fig. 21B).
In view of the same identification of features applied above (to
Figures 21B and 21C), Figures 21A and 21B show that, in a leaf’s “radially
inward” movement, the “first upstream gap portion” of the free end of a leaf
(being more proximate the fixed end thereof) increases less than the “second
upstream gap portion” of the free end of the leaf (being more proximate the
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tip thereof). This is what the first part of the second “wherein” clause of
claim 1 recites.
Turning to the second part of the second “wherein” clause, and
applying the same condition (i.e., “if the free end of the at least one of the
leafs moves in the radially inward direction”), Grondahl’s “first downstream
gap portion” (being more proximate the fixed end) decreases less than the
“second downstream gap portion” (being less proximate the fixed end).
Again, this disposition is what the second portion of the second “wherein”
clause of claim 1 requires.
In view of the foregoing analysis, the Appellant does not persuade us
of error in the rejection of independent claim 1 under 35 U.S.C. § 103(a).
Dependent Claims 4, 6, 7, and 9–11
The Appellant states that “[d]ependent claims 4, 6, 7 and 9–11 recite
additional distinguishing features over the proposed combination of
Grondahl and Awtar.” Appeal Br. 17. However, of these claims, the
Appellant presents arguments only with regard to dependent claim 11, which
recites:
11. A leaf seal according to claim 1, wherein each leaf is
formed of a monolithic structure,
wherein each leaf has a continuous, uninterrupted cross-
section between the first upstream gap portion and the first
downstream gap portion, and
wherein each leaf has a continuous, uninterrupted cross-
section between the second upstream gap portion and the
second downstream gap portion.
The Appellant contends that neither Grondahl nor Awtar discloses or
suggests the features of “each leaf” being “formed of a monolithic structure”
and having the claimed “continuous, uninterrupted cross-section[s].”
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Appeal Br. 17–19. According to the Appellant, Grondahl fails to meet these
limitations, because, “[a]s shown in Figs. 21A–21C of Grondhal [sic], the
leafs are individual segments that are sequentially arranged one after another
in the aggregate.” Id. at 17. As to Awtar, the Appellant argues (Reply
Br. 7–8) that Awtar’s “compliant plate member 16,” of Figure 1 thereof, is
riven by gaps (“multiple slots 20”) (see Awtar ¶¶ 14–15) that preclude
satisfaction of the identified limitations of claim 11.
In response to the Appellant’s argument concerning the Grondahl
reference, the Examiner states:
[The Appellant’s] analysis appears to examine multiple leaves
as if they were one leaf, which is clearly improper as the claim
recites “each leaf” individually. In Grondahl, Figures 21A–21C
(which do show the cross-section in question) . . . show all of
the leaves of the seal, which creates the stacked structure in the
illustrations (see also, Figures 15–19 and 24). When examined
fairly, each leaf in that stack has a continuous, uninterrupted
cross-section, which is between the second upstream gap
portion and the second downstream gap portion (again, this is
the radially outer portion of the leaves). The individual leaves
are not interrupted in the axial direction. There are gaps
between leaves, but the claim only considers “each leaf”,
separately.
Answer 6–7.
We agree with the Examiner’s interpretation of the claim language,
and the Examiner’s findings that “each leaf” in the cited portions of
Grondahl is “formed of a monolithic structure” and possesses “a continuous,
uninterrupted cross-section between the first upstream gap portion and the
first downstream gap portion” and “a continuous, uninterrupted cross-section
between the second upstream gap portion and the second downstream gap
portion.”
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Therefore, the Appellant does not persuade us of error in the rejection
of dependent claims 4, 6, 7, and 9–11 under 35 U.S.C. § 103(a).
CONCLUSION
In summary:
Claims
Rejected
35 U.S.C. § Reference(s)/Basis Affirmed Reversed
1, 4, 6, 7,
9–11
103(a) Grondahl, Awtar 1, 4, 6, 7,
9–11

TIME PERIOD FOR RESPONSE
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)(1)(iv).
AFFIRMED