Prosecution Insights
Last updated: April 19, 2026
Application No. 18/491,997

METHOD AND SYSTEM FOR DIRECT ELECTRIC HEATING OF A DOUBLE-WALLED PIPE FOR TRANSPORTING FLUIDS

Final Rejection §103§112§DP
Filed
Oct 23, 2023
Examiner
ROSARIO-APONTE, ALBA T
Art Unit
3761
Tech Center
3700 — Mechanical Engineering & Manufacturing
Assignee
Saipem S A
OA Round
2 (Final)
54%
Grant Probability
Moderate
3-4
OA Rounds
4y 1m
To Grant
81%
With Interview

Examiner Intelligence

Grants 54% of resolved cases
54%
Career Allow Rate
253 granted / 467 resolved
-15.8% vs TC avg
Strong +27% interview lift
Without
With
+27.0%
Interview Lift
resolved cases with interview
Typical timeline
4y 1m
Avg Prosecution
48 currently pending
Career history
515
Total Applications
across all art units

Statute-Specific Performance

§101
0.7%
-39.3% vs TC avg
§103
43.1%
+3.1% vs TC avg
§102
21.8%
-18.2% vs TC avg
§112
27.5%
-12.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 467 resolved cases

Office Action

§103 §112 §DP
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 Objections Claim 6 is objected to because of the following informalities: in lines 10 and 11, the limitation “each point corresponding to each point corresponding to at least one pipeline section” should read “each point corresponding to at least one pipeline section”. Appropriate correction is required. 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 18 and 19 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. In claim 18, the limitation “wherein each pipeline section is electrically insulated from an adjacent pipeline section with a bulkhead configured to sealingly close the annular space and ensure a mechanical and electrical connection between the inner shell and the outer shell” is unclear how does the bulkhead provide electrical insulation and electrical connection at the same time. Is the bulkhead an electrical insulator or an electrical conductor? Claim 19 is rejected due to its dependency from claim 18. 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 6-17 are rejected under 35 U.S.C. 103 as being unpatentable over Bass (US 2015/0276113) in view of Ahlen (WO 90/05266). Regarding claim 6, Bass teaches a Direct Electrical Heating system (Fig. 1, 3A, 14, 19) of a Pipe-In-Pipe pipeline for transporting fluids (p.0108), the pipeline comprising a steel inner shell (101) intended to transport fluids and a steel outer shell (103) positioned around the inner shell while being coaxial therewith (as shown in Fig. 1, 3A, 14, 19) to delimit an annular space (105) therewith, the system comprising: a plurality of mechanical links (205) between the inner shell and the outer shell which are positioned at different intervals of the pipeline (as shown in Fig. 1, 3A, 14, 19; para. 0006; 0009; 0024; 0026); an electrical and thermal insulation between the inner shell and the outer shell which is positioned over the entire length of the pipeline (p.0055 or 201 and 211); and an alternating electric current generator (109) configured to apply an alternating electric current at several points along the pipeline (at each heated segment, thru annulus 105 and carbon steel bulkhead 107; para. 0056; 0060; Fig. 1 and 3A), each point corresponding to at least one pipe section (para. 0056); and each pipeline section comprising an inner shell section (portion of inner shell 101 between bulkheads 107) and an outer shell section (portion of inner shell 103 between bulkheads 107), and wherein the electric current generator is configured to apply the alternating electric current between an outer surface of the inner shell and an inner surface of the outer shell over the entire length of the pipeline so as to heat the inner shell of the pipeline by Joule effect (p.0025; p.0056). Bass fails to disclose further comprising at least one layer made of resistive and ferromagnetic material positioned on the outer surface of the inner shell over the entire length of the pipeline so as to increase the ratio of electric power transmitted to the inner shell. Ahlen teaches a transport pipeline (1) comprising at least one layer made of resistive and ferromagnetic material positioned on the outer surface of the pipeline over the entire length of the pipeline so as to increase the ratio of electrical power transmitted to the pipeline (page 3, lines 33-35). Therefore, it would have been obvious to one having ordinary skill in the art at the time the invention was made to have modified the inner pipe of Bass, with Ahlen, by providing a composite pipe with at least one layer of ferromagnetic material as an alternative to the carbon steel pipe of Bass to assure proper electrical conduction. POSITA would have known that providing a composite pipe with at least one layer of ferromagnetic material as an alternative to the carbon steel pipe would have a reasonable expectation of success and predictable results such as proper electrical conduction. Regarding claim 7, Bass and Ahlen combined teach the system as set forth above, further comprising a jacket (Bass; 207) made of conductive and non-magnetic material (Bass; zinc; p.0060; p.0064-0065; p.0068) positioned on the inner surface of the outer shell over the entire length of the pipeline (Bass; as shown in Fig. 3A, 14). Regarding claim 8, Bass and Ahlen combined teach the system as set forth above, wherein the jacket made of conductive and non-magnetic material is made of aluminum, copper, bronze, brass or zinc (Bass; zinc; p.0060; p.0064-0065; p.0068). Regarding claim 9, Bass and Ahlen combined teach the system as set forth above, wherein the jacket made of conductive and non-magnetic material has a thickness of 1 mm (Bass; p.0068; table 1). Bass and Ahlen combined fail to disclose wherein the jacket made of conductive and non-magnetic material has a thickness between 1 to 6 mm. It would have been obvious to one having ordinary skill in the art at the time the invention was made to provide the claimed jacket thickness, 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. Regarding claim 10, Bass and Ahlen combined teach the system as set forth above, wherein the layer made of resistive and ferromagnetic material is made of electrical steel or amorphous metal (Ahlen; page 3, lines 33-35). Regarding claim 11, Bass and Ahlen combined teach all the limitations of the claimed invention as set forth above, except for, wherein the layer made of resistive and ferromagnetic material has a thickness comprised between 1 and 3 mm. It would have been obvious to one having ordinary skill in the art at the time the invention was made to provide the claimed layer thickness, 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. Regarding claim 12, Bass and Ahlen combined teach the system as set forth above, wherein the mechanical links between the inner shell and the outer shell of the pipeline are annular shoulders evenly spaced over the entire length of the pipeline (Bass; as shown in Fig. 1, 3A, 14, 19; para. 0006; 0009; 0024; 0026). Regarding claim 13, Bass and Ahlen combined teach the system as set forth above, wherein the inner shell and the outer shell of the pipeline each comprise a plurality of shell sections connected end-to-end to each other by weld beads (Bass; p.0059; p.0091), the jacket made of conductive and non-magnetic material and the layer made of resistive and ferromagnetic material having discontinuities at the weld beads (Bass when viewed in combination with Ahlen; p.0059; p.0091; as shown in Fig. 3A, 14). Regarding claim 14, Bass and Ahlen combined teach the system as set forth above, wherein the electrical continuity of the jacket made of conductive and non-magnetic material and of the layer made of resistive and ferromagnetic material is achieved directly through the inner and outer shells (Bass when viewed in combination with Ahlen; as shown in Fig. 1, 3A, 14; Bass teaches a power source 109 connected to the inner 101 and outer 103 pipes, and layer 207 directly in contact with the inner surface of outer pipe 103, and Ahlen teaches a composite pipe with a layer of ferromagnetic material, therefore the combination of Bass and Ahlen will provide electrical continuity of the jacket made of conductive and non-magnetic material and of the layer made of resistive and ferromagnetic material achieved directly through the inner and outer shells). Regarding claim 15, Bass and Ahlen combined teach the system as set forth above, wherein the electrical continuity of the jacket made of conductive and non-magnetic material and of the layer made of resistive and ferromagnetic material is achieved indirectly through a conductive annular ring or a conductive sleeve (Bass; 1400) which are positioned at the weld beads (Bass; as shown in Fig. 14; para. 0091). Regarding claim 16, Bass and Ahlen combined teach the system as set forth above, wherein the annular space is sealingly closed by a metal bulkhead (Bass; 107) configured to provide a mechanical and electrical connection between the inner shell and the outer shell (Bass; para. 0055-0056; 0069; Fig. 3A-3B). Regarding claim 17, Bass and Ahlen combined teach the system as set forth above, wherein the inner shell and the outer shell are connected to each other by intermediate links (209) configured to hold the inner shell and the outer shell together in a coaxial position, wherein each intermediate link is electrically insulated and arranged to prevent electric current passes therethrough (Bass; para. 0090; Fig. 3A and 14). Allowable Subject Matter Claims 18 and 19 would be allowable if rewritten to overcome the rejection(s) under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), 2nd paragraph, set forth in this Office action and to include 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: allowable subject matter is indicated for claims 18 and 19 because the prior art of record does not show or fairly suggest a direct electrical heating system of a pipe-in-pipe pipeline for transporting fluids, wherein each pipeline section is electrically insulated from an adjacent pipeline section with a bulkhead configured to sealingly close the annular space and ensure a mechanical and electrical connection between the inner shell and the outer shell, and wherein at least one pipeline section is supplied with electric current independently and in a middle of the at least one pipeline section by the alternating electric current generator as recited in claim 18. Response to Arguments The nonstatutory double patenting rejection is hereby withdrawn in view of the terminal disclaimer filed and approved on 09/29/2025. Applicant's arguments filed 09/29/2025 have been fully considered but they are not persuasive. Regarding claim 6, Applicant argues that “Bass discloses a current source (109); however, while pipe-in-pipe system in Bass applies the current to the outer pipe (103) and inner pipe (101) using current source (109), the current source (109) in Bass is not described as applying an alternating electric current at several points along the pipeline, wherein each point corresponds to at least one pipeline section.” on remarks page 10, lines 7-11. In response to Applicant’s arguments, Bass teaches an alternating electric current generator (109) configured to apply an alternating electric current at several points along the pipeline (at each heated segment, thru annulus 105 and carbon steel bulkhead 107; para. 0056; 0060; Fig. 1 and 3A), each point corresponding to at least one pipe section (para. 0056); and each pipeline section comprising an inner shell section (portion of inner shell 101 between bulkheads 107) and an outer shell section (portion of inner shell 103 between bulkheads 107), and wherein the electric current generator is configured to apply the alternating electric current between an outer surface of the inner shell and an inner surface of the outer shell over the entire length of the pipeline so as to heat the inner shell of the pipeline by Joule effect (p.0025; p.0056). For these reasons the arguments are not persuasive. Regarding claims 7-19, Applicant relies on the same arguments, therefore, the same response applies. Conclusion Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. Any inquiry concerning this communication or earlier communications from the examiner should be directed to ALBA T ROSARIO-APONTE whose telephone number is (571)272-9325. The examiner can normally be reached M to F; 8am-5pm. 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, Steven Crabb can be reached at 571-270-5095. 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. /ALBA T ROSARIO-APONTE/Examiner, Art Unit 3761 12/12/2025 /ELIZABETH M KERR/Primary Examiner, Art Unit 3761
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Prosecution Timeline

Oct 23, 2023
Application Filed
Jun 20, 2025
Non-Final Rejection — §103, §112, §DP
Sep 29, 2025
Response Filed
Dec 12, 2025
Final Rejection — §103, §112, §DP
Feb 03, 2026
Interview Requested
Feb 12, 2026
Examiner Interview Summary
Feb 12, 2026
Applicant Interview (Telephonic)

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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
54%
Grant Probability
81%
With Interview (+27.0%)
4y 1m
Median Time to Grant
Moderate
PTA Risk
Based on 467 resolved cases by this examiner. Grant probability derived from career allow rate.

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