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 .
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.
Claims 16, 18-21, 23-26, and 28-32 are rejected under 35 U.S.C. 103 as being unpatentable over Bielfeldt taken together with Braun ‘052.
Bielfeldt (Figs. 1 and 2; page 1, line 98 through page 2, line 55) disclose a vertically oriented perforated tray column with a series of vertically spaced horizontal trays (11) (claim 19), wherein vapor rises upwardly through the successive trays (11) via a plurality of perforations (18, 20) in each tray (11) (note that Fig. 1 shows 8 perforated trays 11, thereby meeting the limitations of newly added claim 32) and bubbles through the liquid on each tray, which liquid passes downwardly through the column through a series of vertically aligned, straight downcomer pipes (element 31 is integrally connected in a liquid tight manner to the top end of pipe 32, thus forming a downcomer that structurally and functionally extends above and below the perforated plate 11) (claims 16 and 20), the liquid exiting the lower end of the downcomer to cover the top surface of each successively lower perforated tray, each of the downcomer pipes (31,32) extending above a first perforated tray and below the first perforated tray toward a second adjacent lower perforated tray, the bottom end of each downcomer pipe (31,32) having an end guard (33) associated therewith to maintain the outlet section of the pipe submerged by liquid to prevent vapor from rising through the pipe (claims 16 and 24). The downcomer pipes are arranged in a regular pattern (apparent square pitch, claim 21, see Fig. 1), such that the liquid flow around each downcomer is an even radial flow in all directions from the downcomer (claim 21). The bottom end of each of the downcomer pipes (31,32) terminate above the second tray at a distance greater than the top end of each of the downcomers extend above the first tray (claim 16, see Fig. 2). The end guards (33) below the bottom ends of the downcomer pipes are in the form of a cup having a bottom and perimetral wall extending upwardly from the bottom (claim 25). All of the liquid moving from a higher first tray to a lower second tray passes through the plurality of downcomers (31,32) extending therebetween, the arrangement requiring no inlet area on the subjacent tray for the liquid exiting the downcomer (claim 28). The downcomer pipes have no inlet and outlet other than the inlet section and outlet section at the top and bottom ends of the pipes, respectively (claim 26). It would have been obvious for an artisan at the time of the filing of the application, to modify the integral downcomer inlet cap (31) and the downcomer pipe (32) to be of a single unitary structure, if such were desired, since such would have functioned in the same manner as the disclosed integral structure, the unitary structure saving an assembly step during the installation of the downcomers within the perforated tray tower of Bielfeldt.
With regard to instant claims 18, 23, and 31, Bielfeldt substantially discloses the structures as recited thereby, except for a specific recitation as to the length of the extension of the downcomer pipes above the first tray, as set forth by claim 18, and the range of cross-sectional area of the downcomer pipes with respect to the surface area of the first tray, as recited by claims 23 and 31. Wherein the height of the extension of the downcomer pipes above the first tray would have been dictated by the ability of the pressure of the ascending vapors to overcome the liquid head established on the trays by the height of the downcomer inlets above the first tray, it would have been obvious for an artisan at the time of the filing of the application, to set the downcomer upper inlet end height at any operable height to maximize contact between the phases, without imparting an inoperable pressure head for the ascending vapors to overcome. Furthermore, wherein the reference figures appear to indicate an amount of downcomers per tray surface area, as well as an individual downcomer cross-sectional area that would at least approximate the range as set forth by instant claims 23 and 31, it would have been obvious for an artisan at the time of the filing of the application, to optimize the number of downcomers per tray to provide a cross-sectional area having the claimed percentage of surface area, and the size the individual downcomers with regard to their cross-sectional area relative to the tray area, the optimization being by way of routine experimentation with the apparatus as suggested by Bielfeldt.
Bielfeldt, as discussed above, substantially discloses applicant’s invention as recited by instant claims 16, 29, and 30, except for the perforated tray column being used as an absorber of a regenerator of a CO2 removal section of an ammonia plant, or a method of revamping a perforated tray column, particularly as an absorber or a regenerator of a CO2 removal section of an ammonia plant, as recited by instant claims 29 and 30, and the end guard being fixed to the second portion of the downcomer pipe, as now required by the amendments to independent claims 16 and 30.
Braun ‘052 (Figs. 1-4; page 1, lines 70-77; page 2, lines 20-28, 58-65) disclose a vertically oriented perforated tray column, similar to that of Bielfeldt, with a series of vertically spaced horizontal trays (11), wherein vapor rises upwardly through the successive trays and liquid passes downwardly through the column through a series of vertically aligned, straight downcomer pipes, each of the downcomer pipes extending above a first perforated tray and below the first perforated tray toward a second adjacent lower tray, the bottom end of each downcomer pipe (17) having an end guard (23) threadedly fixed thereto (see the top portion of Fig. 4 wherein the end guard is shown to be threadedly attached to the outer surface of the downcomer pipe 17) to maintain the outlet section of the pipe submerged by liquid to prevent vapor from rising through the pipe. The downcomer pipes (17) of Braun ‘052 are arranged in a regular pattern (square pitch, see Fig. 3), such that the liquid flow around each downcomer is an even radial flow in all directions from the downcomer. The bottom end of each of the downcomers terminate above the second tray at a distance greater than the top end of each of the downcomers extend above the first tray (see Fig. 4). The end guards (23) below the bottom ends of the downcomer pipes are in the form of a cup having a bottom and perimetral wall extending upwardly from the bottom. All of the liquid moving from a higher first tray to a lower second tray passes through the plurality of downcomers (17) extending therebetween, the arrangement requiring no inlet area on the subjacent tray for the liquid exiting the downcomer.
Braun ‘052 further discloses that the apparatus thereof is useable as an absorption device. It is noted that applicant admits at page 8, lines 4-7 of the instant specification that the claimed CO2 removal is by a known technique. Given the disclosure by Braun ‘052 that the apparatus thereof is useable as an absorber to perform absorption between countercurrent contacting flows of gas and liquid, it would have been obvious for an artisan at the time of the filing of the application, to utilize the apparatus of Bielfeldt, in view of the teaching by Braun ‘052 for CO2 removal by way of a known absorption technique. Furthermore, in view of the construction of the absorber, as taught by Braun ‘052, it would have also been obvious for an artisan to look to Braun ‘052 as a roadmap to provide for the revamping of an existing perforated tray column to include the downcomer structures as taught by Bielfeldt and Braun ‘052, within a revamped column to allow for the removal of CO2 by way of a known absorption technique. Lastly, in view of the threaded attachment of the end guard (23) to the bottom end of the downcomer pipe (17), as taught by the upper portion of Figure 4 of Braun ‘052, it would have been obvious for an artisan at the time of the filing of the application, to modify the structure used to fix the position of the end guard (33) of Bielfeldt relative to the downcomer pipe outlet end, to a simpler direct threaded structure that would fix the end guard directly to the bottom end of the downcomer pipe, in view of the notoriously well known threaded connection between the elements as taught by Braun ‘052.
Response to Arguments
Applicant's arguments filed February 25, 2026 have been fully considered but they are not persuasive. With regard to applicant’s arguments as set forth with the amendment and RCE filed on February 25, 2026, the lone argument relative to the prior art rejection is that the applied prior art fails to teach fixing the end guard to the second portion (bottom end portion) of the downcomer pipe. As clearly stated in the amended rejection statement above, Braun ‘052 clearly discloses a threaded connection to fixedly attach the end guard to the bottom end of the downcomer pipe, in a well known manner.
Allowable Subject Matter
The following is a statement of reasons for the indication of allowable subject matter: While the currently presented claims are not considered to contain allowable subject matter for the reasons as set forth above, the undersigned is of the opinion that the addition of the following passage to the independent claims would render the claims allowable over the prior art currently of record. As such it is suggested that applicant further amend independent claim 16, on line 27, and independent claim 30, on line 31, after the phrase, “the second perforated tray” and before the semi-colon immediately thereafter, by inserting, --, thereby creating a free space defining an open vertical space absent any internal elements of the column between a plane defined by a lowermost portion of the end guard fixed to each of the first plurality of downcomer pipes and a plane defined by an inlet section of the first portion of each downcomer pipe of the second plurality of downcomer pipes that is axially aligned with a corresponding one of the first plurality of downcomer pipes--.
While the language suggested to be added to the independent claims is considered to find support in the originally filed disclosure, specifically the disclosure of Figure 1 of the drawings and lines 14-18 on page 13 of the substitute specification, as filed on June 11, 2024 by applicant (which correspond to page 12, lines 12-16 of the originally filed specification), applicant may wish to augment the disclosure of the specification to provide literal textural support within the specification.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CHARLES S BUSHEY whose telephone number is (571)272-1153. The examiner can normally be reached M-Th 6:30-5:00.
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/C.S.B/3-20-26
/CHARLES S BUSHEY/ Primary Examiner, Art Unit 1776