Prosecution Insights
Last updated: April 19, 2026
Application No. 18/552,550

MIXING ASSEMBLY AND METHOD FOR CONTROLLING MIXING OF GREEN LIQUOR AND A FLOCCULATION AGENT

Non-Final OA §103
Filed
Sep 26, 2023
Examiner
MINSKEY, JACOB T
Art Unit
1748
Tech Center
1700 — Chemical & Materials Engineering
Assignee
VALMET AB
OA Round
1 (Non-Final)
68%
Grant Probability
Favorable
1-2
OA Rounds
2y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 68% — above average
68%
Career Allow Rate
550 granted / 803 resolved
+3.5% vs TC avg
Strong +34% interview lift
Without
With
+33.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
48 currently pending
Career history
851
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
46.7%
+6.7% vs TC avg
§102
26.7%
-13.3% vs TC avg
§112
9.9%
-30.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 803 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 with traverse of Group I in the reply filed on 7/07/2025 is acknowledged. The traversal is on the ground(s) that the amended claims include a limitation not covered by the Lieberherr reference and therefore can break unity of invention. This is not found persuasive because an updated review of the new limitations has still shown to lack unity as lack of unity can be shown with multiple references utilized MPEP1850. The requirement is still deemed proper and is therefore made FINAL. Claims 40 and 42-44 are withdrawn from further consideration pursuant to 37 CFR 1.142(b), as being drawn to a nonelected Group II, there being no allowable generic or linking claim. Applicant timely traversed the restriction (election) requirement in the reply filed on 7/07/2025. 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. This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention. Claim(s) 23-39 are rejected under 35 U.S.C. 103 as being unpatentable over Lieberherr, DE 2550131 (already of record) in view of Zou et al, US Patent Publication 2015/0197439. Regarding claim 23, Lieberherr teaches a green liquor treatment arrangement (the apparatus of the reference is capable of working on green liquor) comprising: a mixing assembly for controlling mixing of green liquor and a flocculation agent (see figures), the mixing assembly comprising: a mixing vessel having a first end and a second end (see figure 4), a mixing vessel inlet configured to supply green liquor and flocculating agent to the mixing vessel in the vicinity of the first end (see page 7 of translation, claim 8 and figure 4), a mixing vessel outlet configured to remove flocculated green liquor from the mixing vessel in the vicinity of the second end (see figure 4), a stirring device that is rotatably arranged in a vicinity of the first end (see figure 4)and configured to mix the green liquor and flocculation agent by stirring (described in pages 6 and 7 of the provided translation), wherein the mixing vessel has a length from a center of the mixing vessel inlet to a center of the mixing vessel outlet (see figure 4), the mixing vessel has a maximum width that is perpendicular to a center axis that extends from the first end to the second end (see figure 4), and said length is at least 1.5 times the maximum width (page 6 of the translation includes an example of a width of 400 mm and a length of 800 mm making a ratio of 2). Lieberherr teaches that the liquid is removed form the outlet for further processing but is silent on that further processing being removal of flocculated matter through sedimentation. In the same field of endeavor of flocculating materials, Zou teaches that once the flocculated particles are suspended into large particles, they can be removed through a sedimentation process [0043]. It would have been obvious to one of ordinary skill in the art at the time of the invention to utilize Zou’s additional treatment of the flocculated materials after mixing to separate by a conventional means as sedimentation in the Lieberherr setup, as this additional step would not provide any undo modifications to add an additional processing step that is both conventional and has a high level of succusses it is commonly utilizing in the industry. Regarding claims 24 and 34, Lieberherr remains as applied above and further teaches the length width ratio is 2 (page 6) and cylindrical. Regarding claims 25-27, Lieberherr remains as applied above and further teaches that conically positioned components are welded to the walls of the device (see pages 6-7 and claim 11) with a propeller on an agitator motor is in the middle of the devices axis (page 6 items 9 and 11). Regarding claims 28-31, Lieberherr remains as applied above and further teaches the inner to outer connection pieces have a size ratio of around 1:10 with an example of 80 mm and 25 mm (see page 6 of translation). Regarding claims 32 and 33, Lieberherr remains as applied above and further teaches that the motor can be adjustable to operate the desired speed (page 7) and gives an example of the water flow inlet operating at 3200 m/hr (which is 0.889 m/s, which is greater than the claimed 0.3 m/s). Regarding claim 35, Lieberherr remains as applied above and further teaches an embodiment (figure 5) were the inlet to the vessel is narrower than the outlet as shown by the inlet at A3 enters the vessel in section 5 which is a smaller width than the exit at A4. Regarding claim 36, Lieberherr remains as applied above and further teaches a vertical alignment is possible (page three of translation). Additionally a mere rearrangement of position would have been obvious to one of ordinary skill in the art as the same end result would occur in a closed mixing vessel. Regarding claim 37, Lieberherr remains as applied above and further teaches a volume of less than 10 meters cubed (400 mm and 800 mm length and width is less than 10 meters cubed). Regarding claims 38-39, Lieberherr remains as applied above and further teaches that the inlet and outlet are near the ends of the vessel (as shown in figure 4). While a numerical calculation for less than 20% cannot be explicitly provided the discloser of entering and exiting at opposite ends of the vessel paired with the figures would provide an implicit teaching readily understood by one of ordinary skill in the art. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to JACOB T MINSKEY whose telephone number is (571)270-7003. The examiner can normally be reached M-F 8-6 PM. 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, Abbas Rashid can be reached at 5712707475. 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. JACOB T. MINSKEY Examiner Art Unit 1741 /JACOB T MINSKEY/Primary Examiner, Art Unit 1748
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Prosecution Timeline

Sep 26, 2023
Application Filed
Feb 19, 2026
Non-Final Rejection — §103 (current)

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

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Prosecution Projections

1-2
Expected OA Rounds
68%
Grant Probability
99%
With Interview (+33.7%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 803 resolved cases by this examiner. Grant probability derived from career allow rate.

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