Prosecution Insights
Last updated: April 19, 2026
Application No. 18/569,137

DIRECT FEED PROPPANT SYSTEM

Non-Final OA §102§103
Filed
Dec 11, 2023
Examiner
SORKIN, DAVID L
Art Unit
1774
Tech Center
1700 — Chemical & Materials Engineering
Assignee
National Oilwell Varco L P
OA Round
1 (Non-Final)
67%
Grant Probability
Favorable
1-2
OA Rounds
3y 2m
To Grant
80%
With Interview

Examiner Intelligence

Grants 67% — above average
67%
Career Allow Rate
787 granted / 1170 resolved
+2.3% vs TC avg
Moderate +12% lift
Without
With
+12.5%
Interview Lift
resolved cases with interview
Typical timeline
3y 2m
Avg Prosecution
43 currently pending
Career history
1213
Total Applications
across all art units

Statute-Specific Performance

§101
0.6%
-39.4% vs TC avg
§103
32.7%
-7.3% vs TC avg
§102
32.8%
-7.2% vs TC avg
§112
27.1%
-12.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1170 resolved cases

Office Action

§102 §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 without traverse of Group I, claims 1-13, in the reply filed on 12 January 2026 is acknowledged. Claim Rejections - 35 USC § 102 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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale, or otherwise available to the public before the effective filing date of the claimed invention. Claim 1-4, 8, 10 and 12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Coughlin (US 2016/0167095): Regarding claim 1, Coughlin discloses a system, comprising a fluid supply system including a blender (20) configured to receive and mix liquid and proppant within a mixing tub to form a proppant slurry; a proppant source (65,68) configured to discharge proppant; and an electrically (see [0082]) driven conveyor (15) extending between the proppant source and the mixing tub of the blender, wherein the conveyor is configured to meter delivery of proppant to the mixing tub of the blender (see [0074] and [0081]). Regarding claim 2, the proppant source is configured to choke feed proppant to the conveyor, such that a speed of the conveyor defines a rate at which proppant is discharged from the proppant source to the conveyor (see [0081]). Regarding claim 3, the proppant source is coupled to an enclosure substantially encompassing the conveyor, the enclosure configured to limit a maximum proppant depth on the conveyor (see Figs. 2 and 4). Regarding claim 4, the proppant source includes a plurality of proppant containers (see [0088]), each of the plurality of proppant containers configured to discharge proppant onto the conveyor through a discharge chute extending into the enclosure. Regarding claim 8, Coughlin discloses a system, comprising a fluid supply system including a blender (20) configured to receive and mix liquid and proppant within a mixing tub to form a proppant slurry; a proppant source (65,68) configured to discharge proppant; an electrically (see [0082]) driven conveyor (15) extending between the proppant source and the mixing tub of the blender, the conveyor configured to metered delivery of proppant to the mixing tub of the blender (see [0074] and [0081]); and a control system for controlling a speed of the conveyor to control a rate at which proppant is delivered to the blender (see [0081]). Regarding claim 10, a first sensor is located below a distal end of the conveyor, first sensor in signal communication with the control system and configured to monitor the rate at which proppant is delivered to the blender (see [0081]). Regarding claim 12, a second sensor is located within a passage guiding proppant slurry out of the blender, the second sensor in signal communication with the control system and configured to monitor a concentration of the proppant slurry (see [0081). 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. 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 5-7 and 9 are rejected under 35 U.S.C. 103 as being unpatentable over Coughlin (US 2016/0167095). The system of Coughlin was discussed above: Regarding claim 5, Coughlin further discloses the conveyor having first (165) and second (115) portion both leading to blender (20) (see [0097]), although it is not expressly stated that they are at an angle. It would have been obvious for one of ordinary skill in the art before the effective filing date to have selected the orientation of the two portions, such as at an angle, to delivery material from two locations to the blender as disclosed. Regarding claim 6, Coughlin further discloses the conveyor having first (165) and second (115) portion both leading to blender (20) (see [0097]), although it is not expressly stated that they are adjacent and parallel. It would have been obvious for one of ordinary skill in the art before the effective filing date to have selected the orientation of the two portions, such as at and parallel, to delivery material from to locations to the blender as disclosed. Regarding claim 7, Coughlin further discloses plural containers (see [0088] and [0096]). Regarding claim 9, Coughlin further teaches a variable frequency drive (see [0019] and [0081]); however, the drive is not for the conveyor. It would have been obvious for one of ordinary skill in the art to have utilized a variable frequency drive for the conveyor to achieve the conveyor speed control discussed in [0074] and [0081]). Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Coughlin (US 2016/0167095) in view of Petri (US 2016/0207657). The system of Coughlin was discussed above. The first sensor being ultrasonic is not explicitly disclosed. Petri teaches providing a conveyor with an ultrasonic senor to measure flow rate (see [0096] and [0097]). It would have been obvious for one of ordinary skill in the art before the effective filing date to have utilized an ultrasonic sensor as taught by Petri to measure flow rate. Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Coughlin (US 2016/0167095) in view of Scharmach (US 2017/0212029). The system of Coughlin was discussed above. A nuclear densitometer is not disclosed. Scharmach explains in [0006] to [0011] that nuclear densitometers are well know for measuring concentration. It would have been obvious for one of ordinary skill in the art before the effective filing date to have employed a nuclear densitometer to measure concentration because Scharmach explains that such is “common”. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to DAVID L SORKIN whose telephone number is (571)272-1148. The examiner can normally be reached 7am-3:30pm. 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, Claire X Wang can be reached at (571) 270-1051. 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. DAVID L. SORKIN Examiner Art Unit 1774 /DAVID L SORKIN/Primary Examiner, Art Unit 1774
Read full office action

Prosecution Timeline

Dec 11, 2023
Application Filed
Mar 02, 2026
Non-Final Rejection — §102, §103 (current)

Precedent Cases

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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
67%
Grant Probability
80%
With Interview (+12.5%)
3y 2m
Median Time to Grant
Low
PTA Risk
Based on 1170 resolved cases by this examiner. Grant probability derived from career allow rate.

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