Prosecution Insights
Last updated: July 17, 2026
Application No. 18/371,817

HIGH-EFFICIENCY SEAL COMPOSED OF CARBON NANOTUBES

Final Rejection §103
Filed
Sep 22, 2023
Priority
Dec 01, 2022 — provisional 63/429,192
Examiner
KONERU, LAKSHMI S
Art Unit
3675
Tech Center
3600 — Transportation & Electronic Commerce
Assignee
Ut-battelle LLC
OA Round
4 (Final)
63%
Grant Probability
Moderate
5-6
OA Rounds
1m
Est. Remaining
79%
With Interview

Examiner Intelligence

Grants 63% of resolved cases
63%
Career Allowance Rate
312 granted / 498 resolved
+10.7% vs TC avg
Strong +16% interview lift
Without
With
+16.2%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
24 currently pending
Career history
525
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
89.0%
+49.0% vs TC avg
§102
9.6%
-30.4% vs TC avg
§112
0.2%
-39.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 498 resolved cases

Office Action

§103
DETAILED ACTION Notice of Pre-AIA or AIA Status The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Election/Restrictions Applicant’s election without traverse of Group I, Claims 1 - 19 in the reply filed on 11/25/2024 is acknowledged. Response to Arguments Applicant's arguments filed 02/23/2026 have been fully considered but they are not persuasive. Applicant argues that Tabbita does not disclose an annular substrate, a shaft hole, or a shaft. The brush seal is a linear brush seal. Examiner notes that Tabbita Col 1 Lines 1 – 15 discloses the brush seal sealing between a stationary element and a rotating element, which include a shaft and a shaft hole with an annular substrate including an annular brush seal and annular plates, around the shaft. Applicant argues that Tabbita does not disclose the bristles extending outwardly from and around the inner periphery of the ends of plates 14 and 16 of Tabbita. Examiner notes that Tabbita discloses the bristles 12 extending outwardly from and around the inner periphery of the metal mesh substrate 18. Applicant argues that Tabbita cannot be combined with Bahr, as Bahr forms a seal by swelling the sealing element and Tabbita forms a seal with the bristles between the two elements. Examiner notes that the combination of Tabbita and Bahr teaches that the carbon nanotubes provide exceptional mechanical strength to the seal. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 1 – 13 and 16 - 19 are rejected under 35 U.S.C. 103 as being unpatentable over Tabbita et al. (U.S. Patent # 7181843) in view of Bahr et al. (U.S. PG Pub # 20120312560). Regarding Claim 1, Tabbita discloses a sealing device (10, fig 1) comprising : a metal annular substrate (substrate with 14, 16, 18, Col 4 Lines 21 - 26 – packing material 18 is made of fine metal powder 325 mesh; metallic backing plates 14, 16) comprising an inner periphery defining a shaft hole (hole of 14, 16, 18 with shaft 22). Tabbita does not disclose a plurality of carbon nanotubes extending outwardly from and around the inner periphery into the shaft hole. However, Bahr teaches a plurality of carbon nanotubes (302 with carbon nanotubes) extending outwardly from and around the inner periphery into the shaft hole (carbon nanotubes 302 extending outwardly from 303 and around the inner periphery of 302 into the shaft hole of 303, fig 3A and 3B). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to replace the bristles of Tabbita with the carbon nanotubes as in Bahr with a reasonable expectation of success so that the carbon nanotubes can be functionalized to increase or decrease the swell rate, by enhancing or retarding the rate at which an activation means is taken up by the sealing element (Bahr Para 0076) and the carbon nanotubes provide exceptional mechanical strength to the seal. Regarding Claim 2, the combination of Tabbita and Bahr discloses the sealing device, wherein the annular substrate comprises a first annular frame member (Tabbita 14, fig 1) and a second annular frame member (Tabbita 16, fig 1), the second annular frame member axially disposed to the first annular frame member (Tabbita fig 1); and comprises one or a plurality of annular metal mesh substrates (Tabbita 18, fig 1) axially interposed between the first annular frame and a second annular frame (Tabbita metal mesh substrate 18 axially between first annular frame 14 and second annular frame 16, fig 1), wherein a portion of the one or more annular metal substrates extends outwardly from and around the inner periphery into the shaft hole (Tabbita metal substrate 14, 16, 18 extends outwardly from and around the inner periphery into the shaft hole, fig 1), the portion comprising the carbon nanotubes (Bahr - metal substrate 303 with nanotubes 302 from the inner periphery of 303 into the shaft hole). Regarding Claim 3, the combination of Tabbita and Bahr discloses the sealing device. The combination of Tabbita and Bahr does not disclose wherein the plurality of annular metal mesh substrates are axially stacked together and interposed between the first annular frame and the second annular frame. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention, to comprise a plurality of annular metal mesh substrates, as it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art, to provide ease of installation of the annular metal mesh substrates. The combination of Tabbita and Bahr discloses wherein the plurality of annular metal mesh substrates are axially stacked together (Tabbita 18) and interposed between the first annular frame and the second annular frame (Tabbita 18 between 14 and 16). Regarding Claim 4, the combination of Tabbita and Bahr discloses the sealing device. The combination of Tabbita and Bahr does not disclose wherein the plurality comprises up to 100 annular metal mesh substrates. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention, to contrive any number of desirable ranges for the metal mesh substrates limitation disclosed by Applicant, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art, to provide ease of installation of the annular metal mesh substrates. Regarding Claim 5, the combination of Tabbita and Bahr discloses the sealing device wherein the one or the plurality of annular mesh substrates are flexible (Tabbita metallic substrate 18 is flexible). Regarding Claim 6, the combination of Tabbita and Bahr discloses the sealing device wherein each of the annular metal substrates in the plurality of annular metal mesh substrates are substantially identical (Tabbita 18 are identical). Regarding Claim 7, the combination of Tabbita and Bahr discloses the sealing device wherein the annular metal mesh substrate comprises an expanded metal mesh, a perforated metal plate, a welded metal wire mesh, or a woven metal wire mesh (Tabbita Col 4 Lines 21 - 26 – metal mesh substrate 18 is made of fine metal powder 325 mesh). Regarding Claim 8, the combination of Tabbita and Bahr discloses the sealing device wherein the portion of the one or more annular metal substrates that extends outwardly from and around the inner periphery into the shaft hole comprises one or more openings and the carbon nanotubes substantially cover each annular metal mesh substrate and the one or more openings (Bahr carbon nanotubes cover substrate 18 and openings of 14, 16). Regarding Claim 9, the combination of Tabbita and Bahr discloses the sealing device wherein the first annular frame and the second annular frame are substantially identical (Tabbita 14 and 16 are substantially identical), and the first annular frame and the second annular frame and the one or more annular metal substrates are attached (Tabbita Col 2 Lines 60 – 61: 14, 16, 18 are bonded). Regarding Claim 10, the combination of Tabbita and Bahr discloses the sealing device wherein the first annular frame and the second annular frame are substantially identical and each individually comprise a metal (Tabbita Col 4 Lines 26 - 33 – identical first and second metallic frames 14, 16). Regarding Claim 11, the combination of Tabbita and Bahr discloses the sealing device wherein the annular substrate comprises a solid metal substrate (Tabbita metallic substrate 14, 16, 18), and the plurality of carbon nanotubes that extend outwardly from and around the inner periphery into the shaft hole each have a first end attached to the inner periphery of the solid metal substrate and a second end that extends into the shaft hole (Bahr - first end of carbon nanotubes 302 attached to the inner periphery of metal substrate of Tabbita and Bahr - second end of 302 that extends into the shaft hole of Tabbita). Regarding Claim 12, the combination of Tabbita and Bahr discloses the sealing device wherein the sealing device is configured to be mounted on a rotatable shaft (Tabbita 10 on shaft 22). Regarding Claim 13, the combination of Tabbita and Bahr discloses a sealing assembly comprising : a sealing device comprising a metal annular substrate comprising an inner periphery defining a shaft hole (Tabbita - inner periphery of substrate 14, 16, 18) and a rotatable shaft disposed in the shaft hole (Tabbita - shaft 22 in the shaft hole). Tabbita does not disclose a plurality of carbon nanotubes extending outwardly from and around the inner periphery into the shaft hole. However, Bahr teaches a plurality of carbon nanotubes (302 with carbon nanotubes) extending outwardly from and around the inner periphery into the shaft hole (carbon nanotubes 302 extending outwardly from 303 and around the inner periphery of 302 into the shaft hole of 303, fig 3A and 3B). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to replace the bristles of Tabbita with the carbon nanotubes as in Bahr with a reasonable expectation of success so that the carbon nanotubes can be functionalized to increase or decrease the swell rate, by enhancing or retarding the rate at which an activation means is taken up by the sealing element (Bahr Para 0076) and the carbon nanotubes provide exceptional mechanical strength to the seal. Regarding Claim 16, the combination of Tabbita and Bahr discloses the sealing assembly wherein the plurality of carbon nanotubes extending outwardly from the inner periphery into the shaft hole are disposed across the gap and are in sealing contact against the rotatable shaft (Bahr 302 across the gap and contacts Tabbita 22). Regarding Claim 17, the combination of Tabbita and Bahr discloses the sealing assembly wherein the sealing contact prevents fluid from flowing from a first location to a second location, wherein the first location and the second location are disposed on opposite sides of the gap (Tabbita sealing contact prevents fluid across the gap). Regarding Claim 18, the combination of Tabbita and Bahr discloses the sealing assembly wherein the fluid is a gas (Tabbita Technical field: gas seal). Regarding Claim 19, the combination of Tabbita and Bahr discloses the sealing assembly wherein the annular substrate comprises a first annular frame member (Tabbita 14) and a second annular frame member (Tabbita16), the second annular frame member axially disposed to the first annular frame member (Tabbita fig 1). The combination of Tabbita and Bahr does not disclose wherein the plurality of annular metal mesh substrates are axially stacked together and interposed between the first annular frame and the second annular frame, wherein a portion of the plurality of annular metal substrates extends outwardly from and around the inner periphery into the shaft hole, the portion comprising the carbon nanotubes (Tabbita 302 inwardly from 303). It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention, to comprise a plurality of annular metal mesh substrates, as it has been held that mere duplication of the essential working parts of a device involves only routine skill in the art, to provide ease of installation of the annular metal mesh substrates. The combination of Tabbita and Bahr discloses wherein the plurality of annular metal mesh substrates are axially stacked together (Tabbita 18) and interposed between the first annular frame and the second annular frame (Tabbita 18 between 14 and 16), wherein a portion of the plurality of annular metal substrates extends outwardly from and around the inner periphery into the shaft hole, the portion comprising the carbon nanotubes (Tabbita 14, 16, 18 inwardly with 18 comprising Bahr nanotubes). Claims 14 - 15 are rejected under 35 U.S.C. 103 as being unpatentable over Tabbita et al. (U.S. Patent # 7181843) in view of Bahr et al. (U.S. PG Pub # 20120312560) and in further view of Zheng et al. (U.S. PG Pub # 20080224414). Regarding Claim 14, the combination of Tabbita and Bahr discloses the sealing assembly. The combination of Tabbita and Bahr does not disclose comprising a gap between the rotatable shaft and the plurality of carbon nanotubes extending outwardly from the inner periphery into the shaft hole. However, Zheng teaches comprising a gap between the rotatable shaft and the plurality of carbon nanotubes extending outwardly from the inner periphery into the shaft hole (gap between shaft 60 and bristles 50, fig 1). It would have been obvious to one of ordinary skill in the art before the effective filing date of the invention to combine a gap of Zheng between the shaft and the bristles of Tabbita with a reasonable expectation of success so that the gap is provided for related expansion/movement of the brush seal (Zheng Para 0026). The combination of Tabbita, Bahr and Zheng discloses a gap between the rotatable shaft and the plurality of carbon nanotubes extending outwardly from the inner periphery into the shaft hole (Zheng gap between shaft 60 and Bahr 302 with carbon nanotubes ). Regarding Claim 15, the combination of Tabbita, Bahr and Zheng discloses the sealing assembly. The combination of Tabbita, Bahr and Zheng does not disclose wherein the gap is no less than 100 micrometers. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention, to contrive any number of desirable ranges for the gap limitation disclosed by Applicant, since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art, to provide more durability to the seal by reducing the wear of sealing device. Conclusion THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to L. SUSMITHA KONERU whose telephone number is (571) 270-5333. The examiner can normally be reached on Monday – Friday from 9 A.M.- 4 P.M. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Christine Mills can be reached on 571.272.8322. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of an application may be obtained from the Patent Application Information Retrieval (PAIR) system. Status information for published applications may be obtained from either Private PAIR or Public PAIR. Status information for unpublished applications is available through Private PAIR only. For more information about the PAIR system, see http://pair-direct.uspto.gov. Should you have questions on access to the Private PAIR system, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free)? If you would like assistance from a USPTO Customer Service Representative or access to the automated information system, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /L. K./ Examiner, Art Unit 3675 /CHRISTINE M MILLS/Supervisory Patent Examiner, Art Unit 3675
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Prosecution Timeline

Sep 22, 2023
Application Filed
Feb 12, 2025
Non-Final Rejection mailed — §103
Apr 30, 2025
Response Filed
Jul 16, 2025
Final Rejection mailed — §103
Sep 16, 2025
Response after Non-Final Action
Nov 24, 2025
Non-Final Rejection mailed — §103
Feb 23, 2026
Response Filed
Jun 09, 2026
Final Rejection mailed — §103 (current)

Precedent Cases

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
63%
Grant Probability
79%
With Interview (+16.2%)
2y 11m (~1m remaining)
Median Time to Grant
High
PTA Risk
Based on 498 resolved cases by this examiner. Grant probability derived from career allowance rate.

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