Prosecution Insights
Last updated: April 19, 2026
Application No. 18/006,014

THIRD-STAGE SYSTEM WITH AUTOMATIC BLEEDING, AND USE THEREOF

Final Rejection §103
Filed
Jan 19, 2023
Examiner
BUI, DUNG H
Art Unit
1773
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Petróleo Brasileiro S.A. - Petrobras
OA Round
2 (Final)
78%
Grant Probability
Favorable
3-4
OA Rounds
2y 7m
To Grant
99%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
962 granted / 1227 resolved
+13.4% vs TC avg
Strong +24% interview lift
Without
With
+24.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 7m
Avg Prosecution
85 currently pending
Career history
1312
Total Applications
across all art units

Statute-Specific Performance

§103
48.1%
+8.1% vs TC avg
§102
26.8%
-13.2% vs TC avg
§112
18.8%
-21.2% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1227 resolved cases

Office Action

§103
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 . 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. Claim Rejections - 35 USC § 103 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. The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows: 1. Determining the scope and contents of the prior art. 2. Ascertaining the differences between the prior art and the claims at issue. 3. Resolving the level of ordinary skill in the pertinent art. 4. Considering objective evidence present in the application indicating obviousness or nonobviousness. Claim(s) 1-9 are rejected under 35 U.S.C. 103 as being unpatentable over Chitnis et al (US 5681450; hereinafter Chitnis) in view of Ribera Salcedo (WO 0141934; hereinafter Salcedo). As regarding claim 1, Chitnis discloses the claimed invention for a third stage system comprises a recycle ejector (400, 410, 415 of figs. 4-5) where a suction side of the recycle ejector is directly connected to a central region or a top of the third stage cyclone vessel via an auxiliary piping to receive a bleed stream of the third stage cyclone vessel. Chitnis does not disclose where a suction side of the recycle ejector is directly connected to a central region or a top of the third stage cyclone vessel via an auxiliary piping to receive a bleed stream of the third stage cyclone vessel and a discharge of the recycle ejector is connected to a central feed of the third stage cyclone vessel. Salcedo teaches its discharge connected to a central feed of the third stage cyclone vessel (annotated fig. 2; pg 1 ln 3-5, pg 3 ln 22-24). It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide its discharge connected to the central feed of the third stage cyclone vessel as taught by Salcedo in order to minimize material loss and enhance efficiency of cyclone systems. PNG media_image1.png 347 468 media_image1.png Greyscale As regarding claim 2, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention except for wherein the third stage system further comprises a flow meter, which is coupled to an ejector output, in which the recycle ejector uses a motive fluid stream variable accordingly. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide a vortex limiter can be installed in the top region of the cyclone leg in order to enhance efficiency of cyclone systems, since it was known in the art as shown in Goerlach-Doht et al (US 20140013999; hereinafter Goerlach-Doht; [0051]). As regarding claim 3, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention except for a vortex limiter can be installed in the top region of the cyclone leg. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide a vortex limiter can be installed in the top region of the cyclone leg in order to enhance efficiency of cyclone systems, since it was known in the art as shown in Carroll (US 20180043292; 150 of fig. 1). As regarding claim 4, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention except for wherein the recycle ejector is internally or externally installed in the third stage cyclone vessel. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein the recycle ejector is internally or externally installed in the third stage cyclone vessel in order to enhance cyclone system performance, since it has been held that rearranging parts of an invention involves only routine skill in the art. In re Japikse, 86 USPQ 70. As regarding claim 5, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention except for wherein a flow rate of motive fluid of the recycle ejector promotes the aspiration of a stream flow rate in the range of 2 to 5%, in relation to the flow rate of the gases that enter the third stage cyclone vessel, wherein the restriction for the maximum value of flow rate of the stream to be aspirated is due to the excessive consumption of motive fluid or erosive aspects. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein a flow rate of motive fluid of the recycle ejector promotes the aspiration of a stream flow rate in the range of 2 to 5%, in relation to the flow rate of the gases that enter the third stage cyclone vessel, wherein the restriction for the maximum value of flow rate of the stream to be aspirated is due to the excessive consumption of motive fluid or erosive aspects in order to enhance cyclone system performance, 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. In re Aller, 105 USPQ 233. With respect to the limitations recited in claim 6, which pertain to the material or article worked upon, it is noted that neither the manner of operating a disclosed device nor material or article worked upon further limit an apparatus claim. Said limitations do not differentiate apparatus claims from prior art. See MPEP § 2114 and 2115. Further, it has been held that process limitations do not have patentable weight in an apparatus claim. See Ex parte Thibault, 164 USPQ 666, 667 (Bd. App. 1969) that states “Expressions relating the apparatus to contents thereof and to an intended operation are of no significance in determining patentability of the apparatus claim.” As regarding claim 7, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention for wherein the flow meter is of a Venturi type (Carrol - 150 of fig. 1). As regarding claim 8, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention except for wherein the flow meter and the recycle ejector are built with ceramic internal parts. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention was made to provide wherein the flow meter and the recycle ejector are built with ceramic internal parts in order to enhance cyclonic system performance, since it has been held to be within the general skill of a worker in the art to select a known material on the basis of its suitability for the intended use as a matter of obvious design choice. In re Leshin, 125 USPQ 416. As regarding claim 9, Chitnis as modified discloses all of limitations as set forth above. Chitnis as modified discloses the claimed invention for wherein the third stage system is applied in multicyclone systems operating at positive pressure, particulate abatement systems, turbo-expander protection systems and in industrial units involving recovering solid products carried by the process gas (abstract). Applicant’s arguments with respect to claim(s) 1-9 have been considered but are moot because of the new ground of rejection. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 nonprovisional extension fee (37 CFR 1.17(a)) 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 DUNG H BUI whose telephone number is (571)270-7077. The examiner can normally be reached Monday-Friday 8:00 - 4:30 ET. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Magali Slawski can be reached on (571) 270-3960. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /DUNG H BUI/ Primary Examiner, Art Unit 1773
Read full office action

Prosecution Timeline

Jan 19, 2023
Application Filed
Apr 03, 2025
Non-Final Rejection — §103
Aug 06, 2025
Response Filed
Oct 11, 2025
Final Rejection — §103
Apr 14, 2026
Examiner Interview Summary
Apr 14, 2026
Applicant Interview (Telephonic)

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

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Prosecution Projections

3-4
Expected OA Rounds
78%
Grant Probability
99%
With Interview (+24.4%)
2y 7m
Median Time to Grant
Moderate
PTA Risk
Based on 1227 resolved cases by this examiner. Grant probability derived from career allow rate.

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