Prosecution Insights
Last updated: April 19, 2026
Application No. 18/685,572

FALLING FILM APPARATUS AND METHOD FOR USING

Non-Final OA §103
Filed
Feb 22, 2024
Examiner
ROBINSON, RENEE E
Art Unit
1772
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Dow Global Technologies LLC
OA Round
1 (Non-Final)
74%
Grant Probability
Favorable
1-2
OA Rounds
2y 11m
To Grant
97%
With Interview

Examiner Intelligence

Grants 74% — above average
74%
Career Allow Rate
759 granted / 1029 resolved
+8.8% vs TC avg
Strong +24% interview lift
Without
With
+23.5%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
35 currently pending
Career history
1064
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
43.3%
+3.3% vs TC avg
§102
14.9%
-25.1% vs TC avg
§112
29.2%
-10.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1029 resolved cases

Office Action

§103
DETAILED ACTION Election/Restrictions Applicant's election with traverse of group I, claims 1-16 and 11-15, in the reply filed on 05 January 2026 is acknowledged. The traversal is on the ground(s) that the claims are entitled to be examined in a single application because they are linked together as to form a single inventive concept. This is not found persuasive because the shared technical feature (a tube insert with circumferential ribs) is not considered to define a contribution over the prior art. In addition to the explanation in the restriction requirement, this is further exemplified by the prior art rejection of the claims below. The requirement is still deemed proper and is therefore made FINAL. Claim Objections Claim 1 is objected to because of the following informalities: The limitation at the end of component (c) (“and for each vertically oriented hollow tube”) appears to be misplaced, as it is defining limitations following in components (d)(i)-(v) and is not limiting to component (c) itself. The office recommends including this limitation on a new line so as to make clear the limitation is intended to define the limitations following in (d)(i)-(v) and furthermore changing the ending punctation to a colon instead of a comma. Appropriate correction is required. 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. 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. Claims 1-6 and 11-15 are rejected under 35 U.S.C. 103 as being unpatentable over Lagana et al (US 4,298,041) in view of Olausson et al (US 2019/0366228). Regarding claim 1, Lagana discloses a falling film apparatus comprising (see Figs. 1 & 2; col. 1, lines 5-9 and 16-19; col. 2, lines 30-57): (a) an outer shell enclosing an interior volume (while not explicitly depicted, its presence is implied – also refer to Fig. 1 of Olausson for evidence that the tubes and sheets would be housed in an outer shell in order to function as intended as a falling film apparatus); (b) upper and lower tube sheets (2, 4) portioning the interior volume into separate upper 1, middle (section between 1 and 5), and lower 5 chambers; (c) vertically oriented hollow tubes 3 having open top and bottom ends, each vertically oriented hollow tube defining a fluid path from the upper chamber to the lower chamber; and for each vertically oriented hollow tube: (d) an associated tube insert (liquid distributor 6) located at the top end of the vertically oriented hollow tube, the associated tube insert comprising a hollow member having: (i) an upper section (ledge 9) residing above the upper tube sheet; (ii) a lower section (cylindrical member 8) extending into the vertically oriented hollow tube; (iii) one or more process fluid openings 13 in the upper section for admitting a process fluid into the tube insert; and (iv) an open bottom end (ending sections of 13) for transferring a thin film of the process fluid from an interior surface of the tube insert onto an interior surface of the vertically oriented hollow tube. Lagana does not disclose circumferential rib(s) residing on the interior surface of the associated tube insert below the process fluid openings. Olausson discloses a falling film evaporation apparatus comprising tubes housed within an outer shell (see Fig. 1; Abstract). The tubes are equipped with formed grooves and/or protrusions, where the falling film surface (interior surface of tube) is advantageously provided with protrusions to create a disturbance in the thin film of liquid (see Fig. 7; [0026]). The protrusions are circumferential (see Figs. 3 & 7) and are considered to be analogous to the claimed ribs. It would have been obvious to a person of ordinary skill in the art at the time of filing the instant claimed invention to modify the apparatus of Lagana by including circumferential protrusions on the interior surface of the tube insert, as suggested by Olausson, in order to create a disturbance in the thin film of liquid flowing thereon. Regarding claim 3, Lagana discloses wherein the upper section of the associated tube insert is adapted to produce a tangential flow of process fluid into the tube insert (see Fig. 4; col. 1, lines 36-41). Regarding claim 4, Lagana discloses wherein the one or more process fluid openings in the upper section of the tube insert are helical slots (see Fig. 4). Regarding claims 5 and 12-15, Lagana in view of Olausson discloses the apparatus further comprising (see Olausson - Fig. 2; [0049]): (e) at least one process fluid inlet port (tube 6) for introducing a process liquid into the upper chamber and into contact with an upper surface of the upper tube sheet; (f) at least one process fluid outlet port 4 for removing at least treated process fluid from the lower chamber; (g) at least one heat exchange fluid inlet port 11 for introducing a heat exchange fluid into the middle chamber; and (h) at least one heat exchange fluid outlet port 15 for removing the heat exchange fluid from the middle chamber. Regarding claim 6, Olausson discloses a process fluid distributor above the upper tube sheet (see Fig. 2, tube 6). Allowable Subject Matter Claims 2 and 11 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The following is a statement of reasons for the indication of allowable subject matter: the additional details with respect to the configuration of the circumferential ribs set forth in the aforementioned claims are considered to define a patentable invention over the cited prior art. Olausson, the modifying reference relied upon for teaching ribs in a tube insert of a falling film apparatus, does not recognize any particular relationship with respect to the size of the ribs as they relate to the inner diameter of the tube insert and the particular curvature of the ribs in relation to the longitudinal thickness of the circumferential rib. Nor does there appear to be sufficient teachings and/or suggestions in the prior art which would motivate a person of ordinary skill to modify the cited references in such a way as to arrive at the claimed embodiment. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to RENEE ROBINSON whose telephone number is (571)270-7371. The examiner can normally be reached Monday - Thursday 8:00a-5:00p and Friday 8:00a-2:00p. 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, In Suk Bullock can be reached at (571)272-5954. 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. /Renee Robinson/Primary Examiner, Art Unit 1772
Read full office action

Prosecution Timeline

Feb 22, 2024
Application Filed
Mar 13, 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
74%
Grant Probability
97%
With Interview (+23.5%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 1029 resolved cases by this examiner. Grant probability derived from career allow rate.

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