Prosecution Insights
Last updated: April 19, 2026
Application No. 18/059,844

SYSTEMS AND TECHNIQUES FOR POLYMER PRODUCT WITHDRAWAL

Non-Final OA §103
Filed
Nov 29, 2022
Examiner
BUI, DUNG H
Art Unit
1773
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Chevron Phillips Chemical Company LP
OA Round
3 (Non-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, 4, 6-8, 10-12, and 15 are rejected under 35 U.S.C. 103 as being unpatentable over Chinh (US 5928612) in view of Vandaele (US 20120093693). As regarding claim 1, Chinh discloses the claimed invention for a downflow polymer product withdrawal system comprising: a withdrawal line (12) coupled to and downstream of the reactor outlet (fig. 1; no number) configured to collect and discharge a product comprising a powder and a carrier gas, the withdrawal line defining a downflow volume, the withdrawal line comprising at least one downward sloped (fig. 1) descending section, the withdrawal line being absent of any non-self draining regions; a lock hopper (14) coupled to and downstream of the withdrawal line, the lock hopper defining a chamber configured to receive at least a portion of the powder and the carrier gas from the withdrawal line; a fill valve (13) between the withdrawal line and the lock hopper; and a discharge valve (16) downstream of the lock hopper. Ching does not disclose a reactor outlet valve coupled to a reactor outlet, wherein the reactor outlet valve is a ram valve. Vandaele teaches a reactor outlet valve coupled to a reactor outlet, wherein the reactor outlet valve is a ram valve. Both Ching and Vandaele are directed to olefin polymerization. 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 reactor outlet valve coupled to a reactor outlet, wherein the reactor outlet valve is a ram valve as taught by Vandaele in order to provide positive solid isolation while allowing controlled, reliable filling of the lock hopper under all operating conditions. Alternatively, 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 reactor outlet valve coupled to a reactor outlet, wherein the reactor outlet valve is a ram valve in order to enhance system performance, since it has been held that mere duplication of parts has no patentable significance, unless a new and unexpected result is produced, since it involves only routine skill in the art. In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960). Chinh as modified does not disclose the claimed invention except for wherein the downflow volume is greater than 80% of a volume of the lock hopper. 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 downflow volume is greater than 80% of a volume of the lock hopper in order to enhance system performance, since it has been held that discovering an optimum value of a result effective variable involves only routine skill in the art. In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). Where patentability is said to be based upon particular chosen volume or upon another variable recited in the claim, the applicant must show that the chosen volume is critical and unexpected results. As regarding claim 4, Chinh discloses all of limitations as set forth above. Chin discloses the claimed invention except for wherein the at least one downward sloped descending section defines a slope relative to a vertical axis greater than or equal to 10 degrees. 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 at least one downward sloped descending section defines a slope relative to a vertical axis greater than or equal to 10 degrees in order to enhance 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. As regarding claim 6, Chinh as modified discloses all of limitations as set forth above. Chinh as modified discloses the claimed invention for wherein the slope permits carrier gas in the withdrawal line to flow upward and above powder in the withdrawal line flowing downward from the reactor (12 of fig. 6c). As regarding claim 7, Chinh as modified discloses all of limitations as set forth above. Chin as modified discloses the claimed invention for wherein the downward sloped descending section is cylindrical (fig. 6a). As regarding claim 8, Chinh as modified discloses all of limitations as set forth above. Chin as modified discloses the claimed invention for wherein the withdrawal line consists of the downward sloped descending section (fig. 6a). As regarding claim 10, Chinh as modified discloses all of limitations as set forth above. Chin as modified discloses the claimed invention for wherein the lock hopper (14) comprises a cylindrical top section joined to a conical bottom section and defines an axis extending through both the cylindrical top section and the conical bottom section (fig. 5). As regarding claim 11, Chinh as modified discloses all of limitations as set forth above. Chin as modified discloses the claimed invention for wherein one or more of the lock hopper axis, the fill valve, and the discharge valve extend along a vertical axis (fig. 5). As regarding claim 12, Chinh as modified discloses all of limitations as set forth above. Chin as modified discloses the claimed invention for wherein a flow diameter of one or both of the fill valve and the discharge valve is greater than or equal to a flow diameter of the withdrawal line (fig. 6a-6d). As regarding claim 15, Chinh as modified discloses all of limitations as set forth above. Chin as modified discloses the claimed invention for a polymerization system (abstract) comprising: a polymerization reactor (1) having a reactor outlet configured to discharge a product comprising a powder and a carrier gas, wherein the powder comprises a polymer; and the downflow polymer product withdrawal system, coupled to the reactor outlet (fig. 1). Claim(s) 3, 5, 9 and 13 are rejected under 35 U.S.C. 103 as being unpatentable over Chinh (US 5928612) in view of Vandaele (US 20120093693), as applied supra, and further in view of Yoshimura et al (US 20190062463; hereinafter Yoshimura). As regarding claim 3, Chinh as modified discloses all of limitations as set forth above. Chinh as modified discloses the claimed invention except for wherein the withdrawal line is absent of any vertical sections. 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 withdrawal line is absent of any vertical sections in order to enhance system performance, since it was known in the art as shown in Yoshimura (L5 of fig. 3). As regarding claim 5, Chinh as modified discloses all of limitations as set forth above. Chinh as modified discloses the claimed invention except for wherein the slope is greater than one or both of an angle of repose of the polymer product or a critical chute angle. 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 slope is greater than one or both of an angle of repose of the polymer product or a critical chute angle in order to enhance system performance, since it was known in the art as shown in Yoshimura (L5 of fig. 3, [0041]-[0042]). Claims 9 and 13 are likewise rejected for reasons analogous to that outline with respect to claim 3 above. Claim(s) 14 is rejected under 35 U.S.C. 103 as being unpatentable over Chinh (US 5928612) in view of Vandaele (US 20120093693), as applied supra, and further in view of Force et al (RU 2438771; hereinafter Force). As regarding claim 14, Chinh discloses all of limitations as set forth above. Chin discloses the claimed invention except for an eructation tube configured to couple a top of the withdrawal line to an above-bed or lower pressure outlet of the reactor. 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 an eructation tube configured to couple a top of the withdrawal line to an above-bed or lower pressure outlet of the reactor in order to enhance system performance, since it was known in the art as shown in Force (112bc, 109c of fig. 2B). Response to Arguments Applicant’s arguments with respect to claim(s) 1 and 3-15 have been considered but are moot because of the new ground of rejection. Conclusion 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, Benjamin L. Lebron can be reached at (571) 272-0475. 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

Nov 29, 2022
Application Filed
Aug 11, 2025
Non-Final Rejection — §103
Sep 02, 2025
Response Filed
Nov 02, 2025
Final Rejection — §103
Feb 05, 2026
Request for Continued Examination
Feb 07, 2026
Response after Non-Final Action
Feb 08, 2026
Non-Final Rejection — §103
Apr 02, 2026
Applicant Interview (Telephonic)
Apr 02, 2026
Examiner Interview Summary

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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
High
PTA Risk
Based on 1227 resolved cases by this examiner. Grant probability derived from career allow rate.

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