Prosecution Insights
Last updated: July 17, 2026
Application No. 18/490,199

FLOTATION UNIT AND FLOTATION METHOD

Non-Final OA §103§112
Filed
Oct 19, 2023
Examiner
GEISBERT, WILLIAM ADDISON
Art Unit
1779
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Metso Finland OY
OA Round
1 (Non-Final)
29%
Grant Probability
At Risk
1-2
OA Rounds
6m
Est. Remaining
52%
With Interview

Examiner Intelligence

Grants only 29% of cases
29%
Career Allowance Rate
6 granted / 21 resolved
-36.4% vs TC avg
Strong +24% interview lift
Without
With
+23.7%
Interview Lift
resolved cases with interview
Typical timeline
3y 3m
Avg Prosecution
19 currently pending
Career history
58
Total Applications
across all art units

Statute-Specific Performance

§103
86.1%
+46.1% vs TC avg
§102
2.5%
-37.5% vs TC avg
§112
4.4%
-35.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 21 resolved cases

Office Action

§103 §112
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 . Specification The disclosure is objected to because of the following informalities: incorrect grammar and typographical errors. Specifically, at least the following errors were noticed upon reading: par. [0002] the term “grinded” is not grammatically correct and should be “ground”. Par. [0023] the word “depth” has been spelled “dept”. Par. [0063 and 0065] “may further comprises” should be “may further comprise”. Also, it appears that the unit “D” may be missing at least once as in par. [0050] as the fraction 2/9 is given with no unit. Appropriate correction is required. Claim Objections Claim 8 is objected to because of the following informalities: typographical errors. Specifically, the phrase “the bottom end the barrier is attached” lacks the word “of”. Appropriate correction is required. Claim Interpretation The following is a quotation of 35 U.S.C. 112(f): (f) Element in Claim for a Combination. – An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. The following is a quotation of pre-AIA 35 U.S.C. 112, sixth paragraph: An element in a claim for a combination may be expressed as a means or step for performing a specified function without the recital of structure, material, or acts in support thereof, and such claim shall be construed to cover the corresponding structure, material, or acts described in the specification and equivalents thereof. The claims in this application are given their broadest reasonable interpretation using the plain meaning of the claim language in light of the specification as it would be understood by one of ordinary skill in the art. The broadest reasonable interpretation of a claim element (also commonly referred to as a claim limitation) is limited by the description in the specification when 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is invoked. As explained in MPEP § 2181, subsection I, claim limitations that meet the following three-prong test will be interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph: (A) the claim limitation uses the term “means” or “step” or a term used as a substitute for “means” that is a generic placeholder (also called a nonce term or a non-structural term having no specific structural meaning) for performing the claimed function; (B) the term “means” or “step” or the generic placeholder is modified by functional language, typically, but not always linked by the transition word “for” (e.g., “means for”) or another linking word or phrase, such as “configured to” or “so that”; and (C) the term “means” or “step” or the generic placeholder is not modified by sufficient structure, material, or acts for performing the claimed function. Use of the word “means” (or “step”) in a claim with functional language creates a rebuttable presumption that the claim limitation is to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites sufficient structure, material, or acts to entirely perform the recited function. Absence of the word “means” (or “step”) in a claim creates a rebuttable presumption that the claim limitation is not to be treated in accordance with 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph. The presumption that the claim limitation is not interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, is rebutted when the claim limitation recites function without reciting sufficient structure, material or acts to entirely perform the recited function. Claim limitations in this application that use the word “means” (or “step”) are being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Conversely, claim limitations in this application that do not use the word “means” (or “step”) are not being interpreted under 35 U.S.C. 112(f) or pre-AIA 35 U.S.C. 112, sixth paragraph, except as otherwise indicated in an Office action. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 8-10 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Regarding claim 8, recitation of the phrase “D is the length of the largest horizontal cross-section of the flotation tank” fails to particularly point out and distinctly claim the subject matter which the inventor regards as the invention. A horizontal cross-section of a flotation tank is two dimensional and is not itself a “length”, and the claim does not identify whether D is intended to be a diameter, maximum width, a perimeter-derived value, or some other dimension of that cross-section. As a result, the claimed range “1/500 D to 4/9 D” lacks a clear and definite reference basis, rendering the scope of claim 8 uncertain. Claims 9 and 10 are rejected due their dependency upon claim 8. 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. Claims 1-7 and 11-15 are rejected under 35 U.S.C. 103 as being unpatentable over Jameson (US20100193408A1), in view of Tuominen (WO2019008217). Regarding claim 1, Jameson discloses a froth flotation unit (Jameson par [0038] “flotation device”), comprising: a flotation tank having a top (Jameson Figs. 1, 3, 5, 7, 9 “froth zone”), bottom (Jameson par. [0048] “cylindrical section”) and one or more walls (Jameson par. [0050] “wall of the vessel” and Figs illustrate one or more walls); a froth collecting launder (Jameson par. [0049] #33) having a froth overflow lip (Jameson par. [0049] “upper lip”); and a launder (Jameson par. [0049] “internal launder”) having a second lip (Jameson par. [0049] “internal lip”); wherein the second lip is arranged closer to the bottom of the flotation tank than the froth overflow lip (Jameson Figs. Illustrate the arrangement). Jameson, however, does not expressly describe the lower internal launder as a “near coarse lander”. Tuominen discloses a froth flotation unit comprising a tank, a first froth collection lander with a first froth overflow lip facing toward the center of the tank, and a second froth collection lander arranged inside the first froth collection launder, the second froth collection launder comprising a froth overflow lip facing the perimeter of the flotation tank, with a froth blocker arranged between the first froth overflow lip and the second froth overflow lip (Tuominen abstract, p. 22 and claim 1). Tuominen further teaches that such a multiple-launder /multiple-lip arrangement is useful where brittle froth cannot easily sustain transportation of ore particles, “and especially coarser particles, towards the froth overflow lip for collection into the launder”, resulting in particle drop-back, and that the blocker may be utilized to direct upwardly flowing slurry and bubble-particle agglomerates closer to a froth overflow lip and/or increase the froth area at the perimeter of the tank closer to a desired overflow lip. It would have been obvious to one of ordinary skill in the art prior to the effective filing date of the claimed invention to modify Jameson’s flotation unit to regard and employ Jameson’s lower internal launder/lip arrangement as the claimed additional “near coarse launder”, in view of Tuominen’s teaching that providing a second internal froth collection launder with its own overflow lip, arranged relative to another overflow lip within the same flotation tank, improves collection efficiency for brittle froth and especially coarser particles that may otherwise drop back before reaching a main froth overflow lip. Regarding claim 2, Jameson in view of Tuominen discloses the froth flotation unit according to claim 1, wherein the flotation tank comprises a froth layer zone having an upper froth layer surface, a lower froth layer surface and a central froth layer cross section (Jameson discloses a froth zone above a settling zone and lower stabilizing zone shown in various Figs.). Regarding claim 3, Jameson in view of Tuominen discloses the froth flotation unit according to claim 1, wherein the froth collecting launder is arranged at the one or more wall(s) of the flotation tank (Jameson shown as launder 33 in the figures and disposed at the side/periphery of the vessel adjacent to the wall, Tuominen p. 10 likewise teaches “the first froth collection launder is arranged on a perimeter of the tank”). Regarding claim 4, Jameson in view of Tuominen discloses the froth flotation unit according to claim 2, wherein the froth overflow lip is located in the froth layer zone, preferably above the central froth layer cross section of the flotation tank (Jameson “upper lip” #32 can be seen in Fig. 1 in the froth layer zone). Regarding claim 5, Jameson in view of Tuominen discloses the froth flotation unit according to claim 1, wherein the near coarse launder is arranged at the one or more wall(s) of the flotation tank (Jameson par. [0048] indicates the internal launder is located at the top of the cylindrical section and this is illustrated in the figures, Tuominen also indicates the launders are at the perimeter of the tank, p. 23 and 24). Regarding claim 6, Jameson in view of Tuominen discloses the froth flotation unit according to claim 2, wherein the near coarse launder comprises a barrier having a lip end comprising the second lip and a bottom end, wherein the bottom end of the barrier is attached to the one or more wall(s) of the flotation tank, and wherein the barrier is configured to create an open space between the one or more wall(s) of the flotation tank and the barrier. (Jameson teaches a lower internal launder arrangement with an internal lip/launder below the froth overflow lip, providing the near coarse launder by suggestion of Tuominen. Tuominen p. 24 further teaches the added barrier structure by disclosing a froth blocker arranged between the first froth overflow lip and the second froth overflow lip and further teaches a blocker geometry that may have a vertex pointing towards the bottom of the tank with side surfaces directed toward respective lips, with figures which depict the blocker spaced inward from the perimeter-side wall region such that the blocker defines a wall-side open region between the perimeter side structure and the blocker and described by Tuominen on p. 22 as providing space between froth subsurfaces A1a and A1b). Regarding claim 7, Jameson in view of Tuominen discloses the froth flotation unit according to claim 6, wherein the barrier is configured for directing coarse particles in froth flotation to the open space for collection. (Tuominen p. 2 lines 10-20 teaches that the froth blockers are arranged to provide “an open froth surface of a flotation tank is divided into two open froth subsurfaces” and the blocker is used to direct brittle froth toward collection because such froth “cannot easily sustain the transportation of ore particles, and especially coarser particles, towards the froth overflow lip for collection into the launder” (lines 30-33)). Regarding claim 11, Jameson in view of Tuominen discloses the froth flotation unit according to claim 2, wherein the froth flotation unit further comprises a gas supply (Jameson par. [0052] discloses and aerator for introducing a supply of air) for introducing flotation gas into a slurry in the flotation tank to form a froth layer in the froth layer zone and a feeding device (Jameson par. [0053] “inlet” mixes feed with a supply of aerated recycle liquid by means of a pump (#41) in various embodiments) for feeding slurry into and/or on top of the froth layer zone in the flotation tank. Regarding claim 12, Jameson in view of Tuominen discloses the froth flotation unit according to claim 1, wherein the froth flotation unit further comprises first overflow means for discharging a first overflow from the froth collecting launder (Jameson abstract describes “bubbles form a froth layer at the upper surface of the settling chamber, and flows over the launder lip”), and second overflow means for discharging a second overflow from the near coarse launder (Jameson abstract “non-hydrophobic particles flow over the lip of an internal launder and are removed as tailings” and suggested by Tuominen that the submerged internal launder is for coarser particles). Regarding claim 13, Jameson in view of Tuominen discloses the froth flotation unit according to claim 1, wherein the froth flotation unit further comprises discharge means (Jameson par. [0050] teaches an opening (39) which removes underflow as a recycle stream) for discharging underflow from the flotation tank. Regarding claim 14, Jameson in view of Tuominen discloses a froth flotation method for treating coarse particles suspended in slurry, wherein the slurry is separated into a first overflow (Jameson par. [0049] “upper lip” provides one overflow point), a second overflow (Jameson par. [0049] “internal lip” provides another overflow point) and an underflow (Jameson par. [0050] teaches an opening (39) which removes underflow as a recycle stream) in the froth flotation unit according to claim 1. Regarding claim 15, Jameson in view of Tuominen discloses the method according to claim 14, wherein the first overflow comprises overflow from the froth collecting launder (Jameson par. [0049] “upper lip” comprises overflow from the launder 33 which collects froth) and the second overflow comprises overflow from the near coarse launder (Jameson par. [0049] “internal lip” comprises overflow from the internal launder which Tuominen suggests is for coarser particles).   Conclusion The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. US7108136 teaches a flotation system that incorporates a barrier arrangement in which an upstanding wall member has a lip end/ overflow weir at its upper end and is configured with surrounding structure to define an open space or gap between related structures for collection and discharge of separated pulp. Any inquiry concerning this communication or earlier communications from the examiner should be directed to WILLIAM ADDISON GEISBERT whose telephone number is (703)756-5497. The examiner can normally be reached Mon-Fri 7:30-5:00 EDT. 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, Bobby RAMDHANIE can be reached at (571)270-3240. 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. /W.A.G./Examiner, Art Unit 1779 /Bobby Ramdhanie/Supervisory Patent Examiner, Art Unit 1779
Read full office action

Prosecution Timeline

Oct 19, 2023
Application Filed
May 04, 2026
Non-Final Rejection mailed — §103, §112 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12678713
SYSTEM FOR CONTINUOUS OIL/WATER SEPARATION USING SUPERHYDROPHILIC OIL/WATER SEPARATION FILTER
3y 12m to grant Granted Jul 14, 2026
Patent 12655040
CRYSTALLIZATION OF SALTS FROM HIGH PRESSURE REVERSE OSMOSIS CONCENTRATE
3y 10m to grant Granted Jun 16, 2026
Patent 12612318
Multi-Stage Circulating Separation Equipment
3y 3m to grant Granted Apr 28, 2026
Patent 12605654
WASTE WATER TREATMENT APPARATUS
3y 0m to grant Granted Apr 21, 2026
Study what changed to get past this examiner. Based on 4 most recent grants.

Strategy Recommendation AI-generated — please review before filing

Get a prosecution strategy drawn from examiner precedents, rejection analysis, and claim mapping.
Typically takes 5-10 seconds — AI-generated, attorney review required before filing

Prosecution Projections

1-2
Expected OA Rounds
29%
Grant Probability
52%
With Interview (+23.7%)
3y 3m (~6m remaining)
Median Time to Grant
Low
PTA Risk
Based on 21 resolved cases by this examiner. Grant probability derived from career allowance rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month