US 697093

I'll run searches against the provided sources and live web to verify.

Now let me check the CAFC docket angle and confirm the USPTO record details.

US 697,093 — Verification Summary

Searches run: Google Patents record, the scanned USPTO/Google patent PDF, and general CAFC/Federal Circuit 2026 docket coverage (courtlistener, cafc.uscourts.gov scheduled-cases lists, Finnegan/Patterson Sheridan 2026 Federal Circuit summaries, Gibson Dunn March-2026 update).

Bibliographic data (from the record)

On the "abstract": this is a 1902 Act-era patent, and the document contains no abstract — abstracts were not a US patent requirement at that time. The functional equivalent is the opening paragraph of the specification:

"My invention relates to an apparatus which is designed for use in conjunction with burners for hydrocarbon oils. It consists of a chamber having diaphragms formed therein to produce tortuous passages through the chamber, steam and oil inlets connecting with one side of the chamber, and a burner-pipe discharging from the opposite side. In conjunction with the inlet-passages is a peculiar valve, through and around which the oil and steam, respectively, pass and are intermingled and mixed at their discharge beyond the valve. This valve also serves to regulate the amount and proportion of steam and oil."

(Source: https://patents.google.com/patent/[US697093](/patent/US697093)/en and the scanned document at https://patentimages.storage.googleapis.com/0e/4c/e2/e9b30c23a0c451/US697093.pdf)

CAFC / 2026 docket search

No 2026 — or any — CAFC docket involving US 697,093 exists, and none should. I searched Federal Circuit docketing notices, the court's 2026 scheduled-cases calendars, and 2026 Federal Circuit case-summary digests and found no reference to this patent number. Two independent reasons:

1. The patent expired April 8, 1919 — its 17-year term ran out 63 years before the Federal Circuit was created by the Federal Courts Improvement Act of 1982 (effective Oct. 1, 1982).
2. The claim was never litigated in a reported action; the only downstream document of record is a 1954 patent that cites it as prior art.

If a "2026 filing" is showing up in a search of yours, it is almost certainly a different identifier, not this patent — see the caveat below.

Identifier ambiguity — flagging per the "no auto-correction" rule

The literal string 697093 resolves to at least three distinct USPTO records. I did not merge them:

1. US Patent No. 697,093 — Larkin, oil-burner vaporizer (this is the one you asked about).
2. Application Serial No. 697,093 — filed March 5, 1924 by Ferdinand Hiemer, which issued as US 1,534,951 ("Internal-combustion motor"). Google Patents' cross-reference table for that patent lists "US697093A" as a priority application number, which can produce false hits.
3. Google Patents' own "Info" table for US 5,282,882 A lists "US 697093 A" as the application-number alias of US 08/006,970 (a 1987 magnesium-refining application by a different assignee entirely).

So a database query on "697093" without the "US" patent-number prefix and without the issue year will return unrelated chemical, mechanical, and metallurgical records. The patent number US 697,093 (issued April 8, 1902) is unambiguous and matches the specification text supplied.

Plain-language overview of the independent claims

The document carries six numbered claims. Claims 1–5 read as independent (each is a self-contained "consisting of…" apparatus claim). Claim 6 is also a stand-alone combination claim, but its printed text is OCR-corrupted — see the uncertainty note. There are no dependent claims.

The unifying inventive idea across all six is a single hand-wheel adjustment that simultaneously and proportionally regulates both the oil inlet and the steam inlet, with the steam acting as an injector to atomize and vaporize the oil.

Claim 1 — Chamber + tortuous passage + single valve at the far end. A hydrocarbon vaporizer/mixer made of (a) a chamber with internal baffles/diaphragms creating a tortuous (zig-zag) path; (b) a discharge tube and jet at one end of that path; (c) a valve at the opposite end; (d) separate, independent oil and steam inlet passages opening against the side of that valve; (e) a threaded portion on the valve located between the oil and steam passages; (f) a port in the valve opening into its hollow interior and aligned with the oil inlet; (g) an annular chamber outside the valve into which the steam is delivered; and (h) a seat that the front end of the valve closes against.

Claim 2 — Same concept, expressed around a valve-chamber with transverse inlets. A chamber with a tortuous passage and a discharge at one end; parallel steam and oil inlet pipes entering the side of a valve-chamber at right angles to its axis; a hollow valve that is turned to advance or retract within the chamber; a lateral port into the valve's hollow interior aligned with the oil-inlet pipe; an annular chamber surrounding the valve that the steam pipe opens into; and a seat interposed between that chamber and the annular steam discharge, by which steam flow is regulated.

Claim 3 — Adds the operator interface and the coupled shut-off. In a hydrocarbon-oil vaporizer and mixer: a vaporizing/mixing chamber; a valve-chamber with a stuffing-box at one end; a valve stem passing through the stuffing-box with a hand-wheel (or equivalent) at its outer end; a valve port opening to the interior aligned with the oil inlet; an annular chamber surrounding the valve opposite the steam inlet and separated from the oil inlet by the screw-threaded portion of the valve; and a seat that the valve end closes against at the same time that the port is occluded by a smooth surface portion of the chamber. (This is the "one motion closes everything" claim.)

Claim 4 — Adds the conical seat and the injector geometry. A vaporizing/mixing chamber plus a valve-chamber having annular interior grooves; oil and steam inlet pipes entering at right angles to the axis and coincident with those grooves; a hollow cylindrical valve with external screw threads mating with corresponding threads between the oil and steam pipes, so the threads both separate the two fluids and open/close the valve as it turns; a conical seat near the discharge end with a mating cone on the valve; a reduced-diameter cylindrical extension beyond the seat on both seat and valve; a chamber surrounding the valve behind the seat that connects to the annular space in front of the valve; and a valve port aligned with the oil inlet, with the valve-chamber's intermediate portion occluding that port in unison with the valve seating.

Claim 5 — The same combination with explicit adjustability of the seat. A vaporizing/mixing chamber; a valve-chamber with oil and steam inlet pipes on one side and annular interior grooves coincident with those pipes; a hollow, screw-threaded valve between the pipes with a port aligned with the oil inlet; an annular chamber surrounding the valve in line with the steam inlet; a conical seat with means for adjusting it longitudinally within the discharge end of the valve-chamber; a mating cone on the valve; and cylindrical extensions of both seat and valve in front of the seat with an annular space between them for steam discharge.

Claim 6 — (OCR-garbled; likely a sleeve-based combination claim). As printed, it recites "the combination of a hydrocarbon-oil [gap in text] … valve having a port opening into it in line with the oil-inlet, said sleeve having a chamber surrounding the valve in line with the steam-inlet, an independent seat, means for adjusting it in the discharge end of the sleeve, and a corresponding formation of the valve closable against the seat, said sleeve having an annular steam-discharge passage exterior to the seat and surrounding the oil-discharge in the end of the valve." The preamble and part of the element list are missing from the scan. I do not have an authoritative, complete text for claim 6 and I will not reconstruct it by inference.

Description highlights (non-claim disclosure)

• Chamber A is cast, rectangular, with diaphragms 2 alternately joined to opposite ends to form the tortuous path; screw-plugs 3 in the ends allow inspection and cleaning.
• Discharge pipe 4 leaves the last leg of the tortuous path and can be run through a boiler-furnace wall so the chamber sits entirely outside the furnace.
• Oil inlet 5 and steam inlet 8 enter the cylindrical valve-chamber via annular grooves 6 and 7; sleeve 9 has openings 10 registering with them.
• Valve body 11 is hollow, threaded into the sleeve between the two inlets; the threaded section separates the steam from the oil at that point. Port 15 opens into the valve's interior in line with inlet 5; because groove 6 encircles the sleeve, oil reaches port 15 regardless of the valve's axial position.
• Conical seat 16 is screw-threaded and removable/adjustable in the sleeve; cone 17 on the valve closes on it; reduced cylindrical portion 18 passes through the seat. Steam escapes as an annular jet around portion 18, catching the oil and driving it forward "with an action similar to that of an injector," atomizing and spraying it.
• Stem 12 passes through stuffing-box 13 and is turned by hand-wheel 14.
• Chamber body is cast iron, made thick enough to store and equalize heat from the hot steam and to buffer supply fluctuations.
• Because seat 16 is longitudinally adjustable, the valve seating, the port occlusion, and the port's position relative to inlet 5 all shift together — so the operator "regulat[es] both steam and oil inlets with a single adjustment." The "re ulate" spacing is an OCR artifact of "regulate."

Uncertainty and data-quality notes

• Dates: the scanned specification's OCR reads "Application filed July 80, 1901" and "Serial No. 70,202." The "80" is an OCR corruption of 30; Google Patents' structured data gives 1901-07-30, which I have used. Filing and priority dates are identical (no earlier priority claimed).
• Text is OCR-derived. The Google Patents full text for this record contains numerous scan artifacts (e.g., "islinteriorly" for "is interiorly," "surrou riding" for "surrounding," "Patcut" for "Patent," "re ulate" for "regulate"). Where a passage is materially ambiguous I have flagged it rather than silently repaired it.
• Claim 6 and the preamble of claim 3 are incomplete in the available text, as noted. "Valveing-box" in claim 3 is almost certainly "valve-chamber, a stuffing-box," but that is a reading of damaged text, not an authoritative transcription.
• No abstract exists for this document; the paragraph quoted above is the specification's summary, not a USPTO abstract field.
• Legal status ("Expired – Lifetime") comes from Google Patents' own disclaimer that status is an assumption and not a legal conclusion. Given the 1919 term expiry, this is not in practical dispute.
• No assignee. Google Patents' "Individual" entries are placeholders for an unassigned patent, not an entity name. I found no recorded assignment for US 697,093.

Bottom line: US 697,093 is a genuine, correctly identified 1902 patent to George H. Larkin of San Francisco for a combined oil-burner vaporizer, mixer, and regulator, with six claims (five clearly independent, one OCR-damaged) and a single forward citation. There is no CAFC 2026 docket for it, and there cannot be one, since the patent expired in 1919 and the court did not exist until 1982.

I'll search for litigation involving US patent 697093.

Let me check the litigation-specific databases for this patent number.

Litigation Search Results — US Patent 697,093

Patents considered literally: U.S. Patent No. 697,093 (not 6,970,93 or 7,697,093), titled "Vaporizer, mixer, and regulator for oil-burners," inventor George H. Larkin (San Francisco, CA), filed July 30, 1901, granted April 8, 1902.

Conclusion: No litigation is known involving US Patent 697,093.

I searched litigation-oriented sources (Unified Patents litigation materials, Justia federal docket documents, CourtListener/RECAP, Docket Alarm, PTAB filings, Federal Circuit and district court records surfaced via web search) and found no case — district court, ITU/ITC, PTAB, or CAFC — in which US 697,093 was asserted, challenged, or otherwise at issue.

Important — no case can be listed

Because no litigation is known, I cannot provide the requested fields (plaintiff, defendant, jurisdiction, case number, filing date, outcome/status) for any case. Reporting fabricated or substituted entries would violate the strict identification rule.

Why this result is expected (context, not a substitute for search results)

• The patent's term is recorded as having expired on April 8, 1919 ("Anticipated expiration"), i.e., 17 years from the 1902 grant under the law then in force.
• It was held by an individual inventor (assignee listed as "Individual"), not a corporate litigant, which further reduces the likelihood of recorded enforcement activity.
• Its "Cited By" record shows only one later citation (US 2,685,294, a 1954 valve patent), indicating minimal modern relevance.

Near-miss numbers that DO have litigation — excluded per your instruction

To make clear these are different patents and are not reported above as results for 697,093:

None of these involve George H. Larkin's US 697,093.

Confidence and caveat

• High confidence that no litigation involving US 697,093 appears in modern publicly indexed litigation databases: the patent predates the modern docketing era, and its subject matter (a steam/gravity-fed oil-burner vaporizer) has no modern commercial use.
• Caveat: Very old 19th/20th-century equity suits were not comprehensively digitized. It is theoretically possible that an unreported Circuit Court case from roughly 1902–1919 exists in paper archives or period Federal Reporter volumes that my searches did not surface. I have no evidence of such a case, and I am not asserting one exists. If you need a paper-era check, the appropriate next step would be a manual review of the Federal Reporter volumes covering 1902–1919 and the Circuit Court equity dockets for the Northern District of California (where the inventor resided), which are not fully available through the databases searched here.

PTAB Activity Report — US 6,970,93 A

Patent: US 6,970,93 A — Vaporizer, mixer, and regulator for oil-burners.
Patent Owner: Individual — George H. Larkin (San Francisco, Cal.)
Application: US 702,0201 (filed 1901-07-30) · Granted: 1902-04-08 · Anticipated expiration: 1919-04-08
Structured source of record: USPTO Open Data Portal — "PTAB proceedings on file"

Proceedings overview

Zero AIA trial proceedings are on file for US 6,970,93 A — no IPRs, no PGRs, no CBMs, no derivations, and no PTAB appeals from any of them; accordingly there is no breakdown to report (0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials), and the bottom-line defensive posture is not the usual "the patent survived IPRs and is hardened," nor even "claims 1–5 were canceled." It is that the patent itself is a 1902 artifact that expired on 1919-04-08, roughly ninety-three years before the AIA trial regime existed (IPR/PGR/CBM became available 2012-09-16). No claim of this patent can be asserted against anyone today, and no AIA trial practice point (estoppel, § 315(b) bar, joinder, discretionary denial) has any bearing on a modern demand letter citing it. The absence of PTAB activity here is not a signal of a hardened patent — it is a chronological impossibility.

Proceedings

None. I do not have a proceeding number, petitioner, or panel to report, and I will not fabricate one. Two items in the public record are sometimes mistaken for PTAB activity and are not:

• US 2,685,294 A (Gold Harold, "Wide range flow rate metering valve," 1949-04-11 → 1954-08-03) appears in the Google Patents "Cited By" table as a forward citation to US 6,970,93. A forward citation is a bibliographic reference by a later patent examiner or applicant — it is not a petition, an AIA trial, or a validity challenge. It is the only forward citation of record.
• The "Similar Documents" list (e.g., US 1,154,868, US 1,881,359, US 1,531,877) is a Google Patents similarity cluster of early-20th-century oil-burner art. It is not a proceeding list.

Web search on 2026-09-27 surfaced no PTAB E2E docket entries, no Final Written Decisions, and no Federal Circuit appeals naming US 6,970,93. Nothing was found that the ODP ingest would have missed.

Why no AIA trial could exist (or be meaningfully filed) here

• Statutory windows closed long ago. A PGR under § 321 must be filed within nine months of grant (i.e., by roughly 1903-01-08) and, independently, requires an effective filing date on or after 2013-03-16 — unavailable for a 1901 priority date. CBM review, even during its 2012–2020 life, required a patent claiming a covered business method used in the practice or administration of a financial product or service; a steam-and-oil vaporizing mixer fails that test on its face, and the Office stopped considering CBM petitions filed on or after 2020-09-16.
• IPR is not age-limited, but it is pointless. Section 311 imposes no filing-date limit, so nothing in the statute literally forbids a 2026 IPR petition against this patent. In practice, however, an expired patent supports no infringement claim, and the Board's settled approach to expired claims (Phillips-style construction, no live amendment interest) makes an IPR a purely academic exercise no rational petitioner funds. The expiration date of 1919-04-08 is the practical end of the inquiry.
• Enforcement is time-barred and laches-barred. With expiration in 1919, damages under § 284/§ 286 (six-year lookback) reach nothing, and an injunction is unavailable against a device accused of practicing claims in the public domain. Any modern "demand letter" invoking this patent number is either a clerical error or a bad-faith scare tactic.

Strategic summary

Claim status: all of claims 1–6 are EXPIRED and in the public domain — none is CANCELED by the PTAB (the Board never touched them), none is "SUSTAINED" in any post-issuance sense, and none is UNTESTED in a way that matters. The claim set consists of independent claims 1, 2, 4, and 5, plus claim 3 (drawn to the stuffing-box/stem subcombination with the port and annular chamber) and claim 6 (the sleeve/removable-seat combination). They issued on 1902-04-08 and lapsed with the statutory term on 1919-04-08. The controlling fact for a defendant is not which claims survived validity review — it is that the patent's term ended before the AIA, before the Federal Circuit existed (1982), and before the modern patent system's pleading standards. I express no view on the claims' original validity; nothing in this record tests it, and the prior-art-heavy 1880s–1900s hydrocarbon-burner art cited as "Similar Documents" suggests the claims would have been a rich invalidity target had anyone bothered.

Estoppel landscape: irrelevant. Section 315(e)(2) estoppel operates only against a petitioner that filed an IPR/PGR that was instituted. With zero petitions ever filed, there is no petitioner, no privy, no institution, and no estoppel — there are also no § 315(b) time-bar issues, no § 325(d) discretionary denials, and no Fintiv analysis. A defendant facing a demand letter citing this patent therefore has no prior IPR art to worry about being estopped from re-raising, and conversely no PTAB-generated invalidity ruling to lean on. Its defense is simpler and absolute: the patent is expired and unassertable.

Pattern signals: none, and none possible. There is no repeat petitioner (there are no petitioners), no PTAB-to-Federal-Circuit appeal track record for this patent owner (George H. Larkin of San Francisco is the sole named inventor, with no assignee of record and no defensive aggregator such as Unified Patents anywhere in the chain — such organizations did not exist in 1902, and a 1919-expired patent would be outside any sane aggregator's scrip). The "Individual" original and current assignee designation is simply the consequence of a lone inventor filing under the 1870/1897 Patent Acts.

Recommended next steps

• If you have received a demand or notice letter citing US 6,970,93: treat it as a red flag about the sender, not as a validity problem. The patent expired 1919-04-08 (see the legal-status field, "Anticipated expiration," in the record above at https://patents.google.com/patent/[US697093](/patent/US697093)/en). Respond by quoting that date and 35 U.S.C. § 286; there is no infringement theory, no damages window, and no injunctive relief available. Preserve the letter — a demand premised on a hundred-and-seven-year-expired patent may itself be actionable.
• If the citation is a portfolio-diligence or freedom-to-operate artifact: the patent is a § 102(b) prior-art document, not an obstacle. Its 1902 publication date means it is prior art as of 1902-04-08 against later-issued claims, and its disclosure (tortuous-passage vaporizing chamber with alternately mounted diaphragms 2, threaded hollow valve 11 with lateral oil port 15, annular steam grooves 6/7 and channels 10, conical valve portion 17 seating on removable conical seat 16, reduced cylindrical extension 18 for annular steam discharge) remains a useful anticipation/obviousness reference for modern fuel-vaporizer and injector-mixing claims.
• If you were expecting a PTAB docket: there is none, and there cannot be a live one. No institution-decision deadlines, no oral hearings, no statutory one-year FWD dates under § 316(a)(11), and no Federal Circuit appeal docket to monitor. I found no proceeding the ODP ingest missed.
• Caveat on confidence: the no-proceedings conclusion rests on (i) the structured ODP block in the prompt and (ii) targeted web searches returning no PTAB E2E, Final Written Decision, or CAFC material. I state that with high confidence for this patent number. I have not verified whether an unrelated later patent or application shares the bare number "697093" in a different numbering series (e.g., the serial number 697,093 appears on US 1,534,951, filed 1924-03-05), so if the demand letter cites a number without the "US … A" publication format, confirm which document is actually being asserted before responding.

I'll search for assignment records and ownership history for this patent.

Let me check a few more targeted sources.

One lead worth verifying — a French technical reference mentions a "Brûleur Larkin" on "Climax" boilers.

Inventors

Verbatim from the grant: "Be it known that I, GEORGE H. LARKIN, a citizen of the United States, residing in the city and county of San Francisco, State of California, have invented an Improvement in Vaporizers, Mixers, and Regulators for Oil-Burners." Witnesses of record are S. H. Nourse and H. F. Asoheck (transcription as printed on the patent). Neither is identified as an employer or assignee; witnesses are not assignees and I make no such inference.

Unusual-pattern check — departures within 12 months of filing: not applicable / unknown. There is only one inventor and no assignee-of-record to depart from. There is no post-1901 correspondence, personnel record, or obituary in the indexed sources that would let me date a departure. I cannot support a statement about the inventor leaving any employer.

One corroborating, non-assignment datum on the inventor's commercial position: contemporaneous technical literature places a "Brûleur Larkin" (Larkin burner) in commercial service years before this application — the April 1894 Bulletin volume at CNAM describes a 1,000-horsepower "Climax" boiler at an exhibition whose firebox "était alimenté par quatre brûleurs Larkin au pétrole" (was fired by four Larkin oil burners), and the same archive's plate is captioned "Brûleur Larkin — Le brûleur employé au chauffage des chaudières « Climax »." Sources: https://cnum.cnam.fr/pgi/fpage.php?BSPI.93/180/100/996/301/630 and https://cnum.cnam.fr/pgi/fpage.php?8XAE399.2/176/110/190/10/180 . This tells us Larkin was an artisan/vendor working in the oil-burner/boiler trade with a product in the field — not that he was employed by a named company. It is context for the "products in commerce" question below; it is not evidence of an assignment.

Original assignee

None. The patent issued to the inventor personally.

• Patent face: "GEORGE H. LARKIN, OF SAN FRANCISCO, CALIFORNIA" — no assignee block, no "assignor to" notation.
• Google Patents records both Original Assignee: Individual and Current Assignee: Individual, and the legal-events table lists only four events: application filed 1901-07-30, priority 1901-07-30, application granted 1902-04-08, anticipated expiration 1919-04-08. No assignment event of any kind appears. (https://patents.google.com/patent/[US697093](/patent/US697093)/en)

Under the practice in force in 1901–02, if the entire interest had been assigned before issuance the patent would ordinarily have issued to the assignee. It did not. So the strong (though not conclusive) inference is that Larkin held title personally at grant.

• Primary line of business: not applicable — there is no corporate owner. The inventor's line of work, as far as the record shows, was hydrocarbon/oil-burner apparatus for boilers and furnaces (the patent's own text: "designed for use in conjunction with burners for hydrocarbon oils"; "If used in conjunction with a boiler or similar furnace, the pipe may pass through the wall of the boiler-furnace, so that the chamber A is entirely outside thereof").
• Did they ship a product embodying the claims? Unclear / not verifiable. A "Larkin burner" was demonstrably marketed for Climax boilers by 1894 (above), but I cannot show that the specific 1894-era device practiced the 1901 claims, which require the particular hollow screw-threaded valve with lateral oil port, annular steam chamber and conical seat (claims 1, 4, 5). Treat "product shipped" as likely in the trade, unproven as to claim scope.
• Current status: the patent itself is Expired — anticipated expiration 1919-04-08 (17 years from the 1902 grant under the then-applicable statute). There is no corporate assignee whose operating/acquired/bankrupt status could be assessed; the individual inventor has no recorded corporate successor, and I have found no obituary, probate, or estate record to date his death. I do not know the disposition of any estate-held interest.

Assignment timeline

Plainly stated: the USPTO Assignment Center / Patent Assignment Search returns no recorded assignment for US Patent 697,093, and Google Patents' legal-events record for the patent contains no assignment event.

I searched the assignment-record surfaces you named (assignmentcenter.uspto.gov; assignment.uspto.gov/patent index) plus Google Patents legal events, and the legacy assignment-document mirror at legacy-assignments.uspto.gov. No reel/frame entry, no conveyance, no assignor/assignee pair, and no correspondent attorney is associated with this patent in any indexed record. There is therefore nothing to list chronologically, and no correspondent of record exists to capture — which is itself the answer to the correspondent question you posed.

Because I cannot produce a single reel/frame, I will not manufacture a table. Fabricating a "Reel 000000/0000" line would be worse than an empty section.

Mandatory caveat on database coverage for a 1902 patent. The online Assignment Search index is built around reel/frame records; reel/frame indexing begins in the mid-20th century, and although USPTO has digitized some far older material, pre-1902 conveyances were recorded in "Liber" lettered volumes and are not reliably retrievable through the modern patent-number query. If an assignment of this patent was ever recorded, the realistic places to find it would be:

1. the original Liber volumes in USPTO's Assignment Branch (searchable only by liber/page or by hand), and
2. San Francisco / Northern District of California county recorder or probate records, if the interest passed through the inventor's estate.

I have no evidence that any such record exists, and I am not asserting that one does. This is a coverage gap, not a finding of non-assignment after 1902 — it is only a firm finding that nothing is recorded in the searchable systems, and that no assignment preceded the grant (established by the fact that the patent issued to Larkin himself).

Timeline diagram

timeline
    title Ownership of US 697093
    1894 : Larkin burners firing Climax boilers
    1901 : Application filed by George H Larkin
    1902 : Patent issued to Larkin personally
    1919 : Patent expired by its own term
         : No assignments recorded to date

Note on scope of this section. Your rules say to stop after the Assignment Timeline when the Assignment Center has no records. I have flagged that plainly above. The remaining three sections are rendered below because your output specification requires them and because they are required to close the analysis — but every signal resolves to the same absence of evidence, and I have kept them short rather than padding them.

NPE / troll-pattern signals

Every signal below is marked against reel/frame evidence, per your constraint. There is no reel/frame evidence to cite for any of them. I mark accordingly and do not substitute naming-based inference.

Structural note on the framework itself: the NPE signal set is designed around post-1980 assertion economics. Applying it to a 1902 patent whose 17-year term ended in 1919 — nearly nine decades before the first modern NPE era — produces "not present" across the board for the trivial reason that the precondition for every signal (a recorded post-issuance assignment in a searchable database) is absent. That is the correct result, but its probative value about troll behavior is nil; what it actually establishes is title continuity.

Verdict

Insufficient data (the "no records, or only the original assignment" branch).

Justification: the original grant issued to George H. Larkin personally — Google Patents lists Original and Current Assignee as "Individual," and its legal-events table (https://patents.google.com/patent/US697093/en) contains no assignment event, only filing 1901-07-30, grant 1902-04-08, and anticipated expiration 1919-04-08. The USPTO Assignment Center / Patent Assignment Search surfaces no reel/frame entry, no conveyance type, no assignor or assignee, and no correspondent of record, so there is no chain to diagram beyond grant and expiration, and not one of the eight NPE signals can be cited to a reel/frame. This is emphatically not the "Defensive / non-asserting" verdict (no aggregator acquired it) and not an NPE verdict of any confidence level (there is no assignee to characterize); it is a 1919-expired patent with unbroken, unrecorded individual ownership.

Verification links:

• USPTO Assignment Center search: https://assignmentcenter.uspto.gov/ (query the patent number; also mirrored at https://assignment.uspto.gov/patent/index.html)
• Google Patents legal events: https://patents.google.com/patent/US697093/en
• Contemporaneous "Larkin burner" product reference (Climax boilers, April 1894): https://cnum.cnam.fr/pgi/fpage.php?BSPI.93/180/100/996/301/630

Caveat, stated once and clearly: for a patent of this vintage the absence of a hit is a statement about database coverage as much as about fact. Pre-1902 assignments were recorded in lettered Liber volumes not reliably reachable by patent-number query in the modern system. If the interest later passed by inheritance or unrecorded conveyance, no online index would show it. I found no evidence of any such transfer, and I am not asserting one exists — but "no record found" here should be read as no searchable record, and a definitive check would require the USPTO Assignment Branch Liber volumes and Northern District of California probate records.

I'll research the citation record for US 697,093 and each candidate reference.

Key finding emerging: US 2,685,294 lists US 697,093 among its own U.S. Patent References. Let me verify the citation direction and gather details on the candidate references.

Prior-Art Analysis — US Patent 697,093

Note on scope: US 697,093 is a 1902 patent, and this section builds on the litigation findings already generated (no enforcement history; one forward citation). I searched the exact number 697093 on the USPTO/Google Patents record and did not substitute results for similar-looking numbers (e.g., 2,685,294 is not 697,093 — it is a later patent that cites it; there is no 6,970,93; 7,697,093 and D697,093 are unrelated).

1. The record for US 697,093 (exact number, literal)

Source: https://patents.google.com/patent/[US697093](/patent/US697093)/en

Critical structural fact: the 1902 printed specification contains no "References Cited" section at all — front-page citation lists did not become standard on U.S. patents until the 1940s. Therefore US 697,093 has zero examiner-cited prior-art references of record. This is the single most important finding for your question, and it means the honest answer to "which claim(s) does each cited reference anticipate" is: no reference of record anticipates any claim, because there are no references of record.

2. The one citation relationship in the family: US 2,685,294 (a citing patent, not prior art)

Sources: https://patents.google.com/patent/[US2685294A](/patent/US2685294A)/en · https://FreePatentsOnline.com/2685294.html (references list) · https://patentimages.storage.googleapis.com/ae/37/3b/e7d7dcf40464fc/US2685294.pdf

§ 102 analysis for US 2,685,294: it cannot anticipate any of claims 1–6 of US 697,093 because it post-dates the 697,093 filing by 47 years and the 697,093 grant by 52 years. Under § 102(a)/(b) the reference must pre-date the applicant's invention or filing; a later document is categorically unavailable as anticipating art. (It could only be relevant in the inverse direction, as a later patent whose validity might be tested against 697,093 as an earlier public disclosure.)

Its analytical value here is different and still real:

• It is evidence of what a 1949–1954 examiner regarded 697,093 as disclosing — namely a hand-wheel-driven screw-threaded valve member advanced/retracted within a passage, cooperating with a convergent/tapered seat at the end, and occluding/opening a port in concert with seating. That reading matches the operative disclosure of 697,093 (elements 11, 15, 16, 17, 18).
• It shows 697,093 fell into the 1949–52 prior-art landscape for flow-metering valves, not merely oil-burner mixers. If 697,093 were ever to be asserted or challenged (contrary to the litigation findings in the earlier section), 2,685,294 would be the natural starting point for a defence-side claim-construction argument on "adjustable flow" limitations.

3. Candidate prior art that actually pre-dates the 1901 filing

Because the patent has no cited references, the only pre-filing art in the 697,093 record is the set of "Similar Documents" machine-associated by Google Patents — an algorithmic similarity list, not examiner citations, and not § 102 art unless independently dated before 1901-07-30. Filtering that list by date:

Pre-filing (potential § 102 art) — dates are the publication/grant dates shown in the record:

Post-filing — excluded as § 102 art on its face (listed here only to show they were checked and removed): US 733,579 (1903), US 758,206 (1904), US 762,129 (1904), US 801,360 (1905), US 943,567 (1909), US 1,085,868 / US 1,105,833 / US 1,153,868? / US 1,159,805? — i.e. US 1,154,868 (1915), US 1,087,768 (1914), US 1,105,833 (1914), US 1,531,877 (1925), US 1,569,805 (1926), US 1,749,401 (1930), US 1,881,359 (1932), US 705,459 (1902), US 703,706 (1902), US 725,003 (1903), US 1,450,631 (1923).

Confidence caveat: for every entry above except US 609,552 and US 158,316 I could not retrieve substantive text, so I will not invent an element-by-element mapping for them. That is a genuine gap, not a judgement that they are irrelevant.

4. Most relevant prior art: US 609,552 (Larkin, "Retort oil-burner")

Sources: https://patents.google.com/patent/[US609552A](/patent/US609552A)/en · https://patentimages.storage.googleapis.com/74/f1/39/041a5f57d248c6/[US609552](/patent/US609552).pdf

Why this is the most dangerous reference for claims 1–6:

1. Same inventor, granted >2 years before the 697,093 filing (Aug 23, 1898 → July 30, 1901). Under the statute actually in force (R.S. § 4886 as amended March 3, 1897), the novelty condition excluded subject matter "patented or described in any printed publication … more than two years prior to his application." An inventor's own earlier U.S. patent granted more than two years before his later application was therefore a statutory bar, not merely prior art. There is no grace-period exception of the modern § 102(b)(1) type available for a 1901 filing. This is the strongest § 102-type attack on the record.

2. Element overlap with claim 1: "a chamber having tortuous passages formed therein, a discharge tube and jet connecting with one end of the passage" — 609,552 discloses chamber A with partition K forming a tortuous path, and burner tips D discharging at one end. It also discloses a steam inlet and an oil inlet on the assembly.

3. Where it falls short: 609,552 has no hollow valve with a lateral port opening to its interior, no screw-threaded valve portion intermediate the oil and steam passages, no annular steam chamber surrounding a valve, and no conical seat closable by a valve cone with a reduced cylindrical extension. Its flow control is by boiler/steam pressure balance, not by a turnable threaded valve. So it does not anticipate claims 1–6 in full; it anticipates at most the mixing-chamber sub-combination, and would be the anchor of a combination attack with US 158,316.

4. Corroborating signal: 697,093's own specification is styled an "Improvement in Vaporizers, Mixers, and Regulators for Oil-Burners," consistent with it being a follow-on to the same inventor's 1898 retort burner.

Caveat: I could not open the bibliographic record for US 609,552 to confirm the inventor's given name, and the serial number is OCR-corrupted. The surname "LARKIN" on the drawing sheet plus subject-matter identity make same-inventorship highly likely but not formally verified here.

5. Second-most relevant: US 158,316 (Robinson, 1874)

Source: https://patents.google.com/patent/[US158316A](/patent/US158316A)/en

§ 102 mapping: this is the closest anticipatory art for the valve concepts, but the correspondence is structural-analogue rather than identical:

• Claim 1's "independent oil and steam inlet passages opening against the side of the valve" and "a seat against which the front end of the valve is closable" → substantially shown (concentric valves with seat d').
• Claims 2, 3, 4, 5's hollow valve with a lateral port into the interior, the threaded portion intermediate the oil and steam passages separating them, and the annular chamber surrounding the valve in line with the steam inlet → not shown. Robinson's valves are solid, separately stemmed, and there is no sleeve/annular-chamber/occlusion-on-seating structure.
• Claim 6's sleeve with an adjustable independent seat and an annular steam-discharge passage exterior to the seat surrounding the oil discharge → partially suggested (adjustable seat, concentric discharge), but the sleeve-with-interior-threads construction is absent.

Because it lacks the hollow ported valve and the sleeve/seat adjustment assembly, US 158,316 cannot anticipate any single claim alone; it is best characterised as § 102(a)/(b) art against isolated limitations and as the obviousness-type counterpart to US 609,552 for the valve claims.

6. Important legal caveat — § 102 did not exist in 1902

Your instruction is to map references to 35 U.S.C. § 102. I have done so, but I must state plainly that this mapping is anachronistic: 35 U.S.C. § 102 was enacted by the Patent Act of 1952, 50 years after this grant, and the AIA § 102 first-inventor-to-file regime postdates it by 111 years. What actually governed US 697,093 was:

• R.S. § 4886 (as amended March 3, 1897): novelty measured against knowledge/use by others in the U.S., and against patents or printed publications anywhere, before the applicant's invention, or more than two years before his application (statutory bar);
• R.S. § 4887 (abandonment/foreign filing), § 4895, § 4900, § 4920 (defences; lack of novelty and want of invention).

If this reference set were to be applied under the 1870 Act framework, US 609,552's same-inventor, >2-years-prior grant is the operative bar; if applied under modern § 102, US 609,552 is § 102(a)(1)/(b)(2)-style art and US 158,316 is § 102(a)(1) art.

7. Summary table of the answer you asked for

8. Confidence and open items

• High confidence: US 697,093 carries no cited prior-art references in the USPTO/Google Patents record, and its only citation relationship is the forward citation to/from US 2,685,294. Verified directly from the patent record and from FreePatentsOnline's reference list for 2,685,294 (which lists "0697093 | N/A | 1902-04-08").
• High confidence: US 2,685,294 cannot anticipate 697,093 (purely on date).
• Moderate-to-high confidence: US 609,552 is the most legally dangerous reference (same inventor, granted >2 years pre-filing), but I could not formally confirm the inventor's given name or the application serial number; the PDF text is OCR-damaged.
• Genuine gap: I retrieved only titles and dates for seven of the nine pre-filing "similar documents." A complete § 102 answer for those would require pulling each PDF (US 335,719; US 190,529; US 275,124; US 407,632; US 389,322; US 441,467; US 529,631) and reading them element-by-element.
• One unrelated hit, flagged but excluded: US 583,818 (F. A. Redmon, San Francisco, "Carbureter," filed 1896-04-01, granted 1897-06-01) surfaced in my searches. It is not in the 697,093 citation or similarity record, so I do not report it as a citation. It is mentioned only because it is a contemporaneous San Francisco carbureter that might merit checking separately.
• No contradiction with the previously generated litigation section: that section's observation that 697,093 has only one "Cited By" record and minimal modern relevance is consistent with everything found here.

Suggested next step if a definitive § 102 position is needed: order the full text of the seven unretrieved pre-1901 "similar documents" and compare them against claim 1's "chamber having tortuous passages formed therein" and claim 2's "parallel steam and oil inlet pipes … transverse to its axis," which are the broadest limitations and therefore the most likely to be met by a single pre-1901 reference.

I'll first try to retrieve the actual content of the pre-1901 references listed on the page, since the page's "Prior Art" section gives only titles and numbers.

A key discovery in that last search: US 609,552 (Larkin, "Retort oil-burner") appears to share the inventor's name. Let me verify that and pull the remaining pre-1901 references.

Obviousness Analysis — US 697,093 under 35 U.S.C. § 103

Method note: I built on the previously generated Verification and Litigation sections rather than restating them. I used the "Prior Art" material on the record page (prior-art keywords; the Similar Documents list; the Cited By list) and then ran live searches to retrieve the actual disclosure text of the pre-1901 references, since the page itself gives only titles and numbers for them. One search batch was truncated by a tool-step limit, which I flag below.

1. Threshold legal caveats (read before the merits)

Three problems precede any § 103 analysis of this document, and I would be misleading you if I buried them.

(a) § 103 did not exist when this patent was granted, and does not apply to it. US 697,093 issued April 8, 1902. Section 103 was created by the Patent Act of 1952 (Pub. L. 82-593, § 103, effective January 1, 1953). Pre-1952 grants were governed by the judicially developed "invention" requirement applied to Rev. Stat. § 4886 — the standard of Hotchkiss v. Greenwood, 52 U.S. (11 How.) 248, 267 (1851) ("the work of a mechanic"), and its later, stricter formulation in Cuno Engineering Corp. v. Automatic Devices Corp., 314 U.S. 84 (1941) (the "flash of genius" language that § 103 was enacted to repudiate — see Graham v. John Deere Co., 383 U.S. 1, 15–17 (1966)). Applying § 103 to a 1902 patent is a retrospective, hypothetical exercise. I have run it that way below, but I am labelling it as such rather than pretending it is a live legal test.

(b) The patent is long dead. Term expired April 8, 1919 (per the record's "Anticipated expiration"). There is no infringement action, no § 282 validity challenge, no IPR, and no CAFC appeal in which an obviousness holding could matter — consistent with the Litigation section above.

(c) No prior art is of record on this patent. 1902-era US patents were not printed with a "References Cited" face listing, and this record has none. The page's "Cited By" contains exactly one entry, US 2,685,294 A (Gold, filed 1949-04-11, issued 1954-08-03). That is a forward citation — it postdates 697,093 by fifty-two years and is not prior art to it under § 102 or under pre-1952 law. So there is no examiner-considered art here, which in a live case would mean no deference under American Hoist & Derrick Co. v. Sowa & Sons, 725 F.2d 1350, 1359–60 (Fed. Cir. 1984).

(d) Date discrepancy, flagged not auto-corrected. The task header says April 26, 2026; the page was fetched 2026-09-27T18:41:38.347Z, and the prior sections are framed in 2026. I noted it and did not reconcile it.

2. What the page's "Prior Art" section actually supplies

Three components, with very different evidentiary weight:

Date-sorting the "Similar Documents" list against the July 30, 1901 filing date. This is the step the page does not do for you, and roughly half the list is disqualified:

Pre-filing — usable as prior art (pre-1952 §§ 4886/4929 and § 102(a)/(b)):

Post-filing — NOT prior art, excluded: US 705,459 (1902), US 733,579 (1903), US 762,129 (1904), US 801,360 (1905), US 943,567 (1909), US 1,087,768 (1914), US 1,105,833 (1914), US 1,154,868 (1915), US 1,531,877 (1925), US 1,569,805 (1926), US 1,749,401 (1930), US 1,881,359 (1932). I flag these because several are the closest-sounding titles on the page ("Crude-oil burner," "Hydrocarbon-burner," "Oil-burner") and a careless analyst would cite them. They cannot be used.

⚠️ This is the single most common error in an obviousness memo on an old patent: the algorithmic "Similar Documents" list is date-blind. Eight of the twenty-six entries are post-1901 on their face.

3. The critical reference: US 609,552 — the inventor's own earlier patent

The searches produced the most important fact in this analysis, and it is not stated anywhere on the page's structured data:

US 609,552, "Retort Oil-Burner," issued August 23, 1898, application filed March 10, 1898, was granted to GEORGE H. LARKIN, "a citizen of the United States, residing in the city and county of San Francisco, State of California."

That is the identical inventor and the identical residence as US 697,093. Source: https://patents.google.com/patent/[US609552A](/patent/US609552A)/en and the scanned document at https://patentimages.storage.googleapis.com/74/f1/39/041a5f57d248c6/[US609552](/patent/US609552).pdf

Why this matters for § 103. A patent that issued more than one year before a later filing is prior art against that later filing even if the same person invented both. Pre-1952, Rev. Stat. § 4886 barred a patent where the invention was "patented or described in any printed publication" before the applicant's invention; today, § 102(b) operates identically with the one-year grace period, and § 103(c) / current § 102(b)(2)(C) common-ownership exceptions do not reach § 102(b)-type art. Larkin's own 1898 patent is therefore squarely available against his 1901 application.

What US 609,552 discloses (as retrieved): concentric oil-vaporizing chamber B inside a steam superheating chamber A cast as one structure; steam admitted via pipe L, circulating around the inner retort and superheated by the firebox; steam then delivered "through the annular channel between the tip I and the partition J" into the vaporizing chamber, where

"the action of the steam passing through the annular channel around the tip I will serve to atomize the oil which has not been vaporized and greatly assist in vaporizing it."

It further discloses removable screw-fitted burner tips (flanged lips spread apart to vary jet size/direction), a screw-plug E with flange F closing and opening the whole apparatus "for inspection or repair," and — notably for the regulator claims — an automatic proportional self-regulation in which rising steam pressure creates back pressure that throttles the oil flow.

Overlap with 697,093: steam jacket around an oil retort; steam atomizing oil at an annular discharge; steam superheated by furnace heat; screw-threaded removable tips; a screw-plug giving access for cleaning; and the concept of coupling steam pressure to oil flow.

What it conspicuously lacks: there is no single adjustable valve; steam and oil are regulated only by the natural interaction of boiler pressure and supply head; there is no hollow translating valve; no lateral port; no annular wall-groove; no conical seat/cone pair; and no tortuous diaphragm-baffled chamber.

4. What the other verified pre-1901 references disclose

Because the page gives only titles, I verified whatever text I could retrieve:

• US 275,124 (Blumenberg et al., 1883) — retrieved in full. Steam and oil induction pipes enter a globulous chamber; "the jets of steam and oil used in forming the vapor … will tend to create a vacuum at the periphery of the globulous chamber, [and] will form double eddying currents, and thereby become thoroughly mingled before being ejected through the burner-tip." Includes a removable metal diaphragm with a funnel-shaped passage "growing smaller toward the burner-tip" for concentrating/mixing the vapor, and separate stop-cocks f on the steam and oil pipes. https://patents.google.com/patent/[US275124](/patent/US275124)
• US 335,719 (Rein, 1886) — retrieved. A valve-plug "made in a beveled or conical form, so that the wear is uniform," with tapered grooves on its exterior "to control the flow of oil or vapor," and explicit criticism of prior needle-valves with "a screw-thread cut on them, which eventually becomes worn out and leaky." https://patentimages.storage.googleapis.com/cf/71/ac/f5ef7cef4fbd89/[US335719](/patent/US335719).pdf
• US 483,885 (Wood, 1892) — retrieved incidentally, not on the page's list. A boss "made hollow and … internally screw-threaded for receiving the screw-threaded shaft of the needle-valve D"; a "narrow conical orifice d, which forms an escape-passage … and a seat for the needle-valve D"; and a lateral air port that admits air "drawn in by the jet of vapor." https://patentimages.storage.googleapis.com/05/a8/1b/92d0377fc36531/[US483885](/patent/US483885).pdf
• General art background — retrieved. Steam-atomizing oil burners ("outside mixing" drooling/shearing types and "chamber" types) were a mature, classified field by 1900; Kermode's steam-jet burner had already introduced a rotation element for good mixing; the "Economist" retort was a widely used Pacific-coast crude-oil vaporizer; and the Richardson system (1866–67) had established that "by the intermixture of waste steam with the air and the liquid fuel" the intensity of combustion was materially increased.

Not retrieved: US 158,316, US 389,322, US 407,632, US 441,467, US 529,631. The batch containing the 529,631 ("Torch") query, and the 407,632 and 389,322 queries, hit the tool-step limit. I did not substitute titles for disclosures — I treat these five as unknown-quantity art and do not rely on them for any limitation.

5. The Graham/KSR framework applied

5.1 Scope and content of the prior art

The field is hydrocarbon-oil burners using steam as the atomizing and vaporizing medium for furnaces and boilers — a crowded art by 1901, as the retrieved historical survey explicitly states ("an enormous development of the steam pulverizing principle"). Under the contemporaneous analogous-arts test of Potts v. Creager, 155 U.S. 597 (1895), the relevant art includes steam-jet burners, vaporizing retorts, mixing chambers, and fuel-metering valves generally.

5.2 Level of ordinary skill

A mechanical engineer or experienced burner mechanic with knowledge of steam-atomizing burner practice, furnace/boiler installation, and the patent literature of the field. No formal degree required; substantial practical skill, and — under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007) — ordinary creativity and the ability to combine a finite number of identified, predictable solutions.

5.3 The differences — what actually distinguishes the claims

Reusing the claim-element breakdown from the earlier sections rather than repeating it, the distinguishing subject matter across all six claims reduces to four structural ideas:

D4 is plainly old — US 609,552's screw-plug E with flange F does the same job, as does US 275,124's removable diaphragm. D3 is very weak: baffled/zig-zag mixing passages were routine, the 1883 Avery arrangement of "a series of perforated diaphragms of gradually decreasing mesh" for atomizing oil in steam is directly on point, and the heat-retaining cast mass is a design choice.

D1 and D2 are where the case is won or lost. No reference I retrieved discloses either combination.

6. Combinations that would render the claims obvious, and the motivation

Combination A — Larkin '552 + Blumenberg '124 (strongest single combination)

Motivation: Same field (steam/oil furnace burners); same inventor's own prior disclosure; expressly the same problem. US 609,552 states that the steam's annular channel "serve[s] to atomize the oil which has not been vaporized," which is a direct admission that oil was escaping the retort unvaporized. US 275,124 supplies precisely the missing remedy: a mixing chamber with "double eddying currents" ensuring the oil and steam "become thoroughly mingled before being ejected through the burner-tip." A skilled mechanic reading Larkin's own patent would be led to add a known eddy-mixing chamber downstream of the annular steam jet. This is a KSR-type combination of two known elements performing their known functions.

Result: Anticipates nothing. Renders D3 obvious and the broad chamber-plus-discharge-plus-valve preamble obvious. It does not reach D1 or D2.

Combination B — Larkin '552 + Blumenberg '124 + Rein '335,719 and/or Wood '483,885

Motivation: The whole point of the Rein and Wood disclosures is metering — Rein's tapered-groove plug "controls the flow of oil or vapor," and Wood's hollow internally screw-threaded boss receives "the screw-threaded shaft of the needle-valve D" which advances/retracts to open or close a "conical orifice … and a seat for the needle-valve D," the vapor jet aspirating air through a lateral port. The problem these address — leakage, wear, and coarse regulation in needle/plug valves — is exactly the problem a burner designer of 1901 would face when adding a regulator to Larkin's back-pressure-controlled '552 burner. Adding a known screw-threaded valve with a known conical seat to a known steam-atomizing burner is a predictable combination of familiar elements, and KSR treats "a known technique … improv[ing] similar devices in the same way" and "use of [a] known [element] according to [its] established function" as within a PHOSITA's reach.

There is even an express statement of the regulatory goal in the retrieved literature: the Priestman vaporizer's governor "regulates at the same time both the oil and the air supply to the vaporizer" — i.e., unitary proportional regulation of fuel and atomizing medium was a recognized desideratum. ⚠️ Caveat: that source is a 1904 treatise describing an engine, and I have not verified the Priestman reduction-to-practice date against 1901. I use it as background on the state of the art only, not as anticipatory art — and under Potts an internal-combustion-engine vaporizer is arguably a non-analogous art.

Result: This combination gets closest on D1's general concept — a turnable screw-threaded member advancing against a conical seat — and on D2's seat/cone geometry. It still does not disclose (a) making that valve hollow so it also constitutes the oil conduit, (b) feeding its lateral port from an annular groove in the chamber wall, (c) using the threaded portion as the fluid separator, or (d) the coupled concurrent port-occlusion-and-seating recited in claims 3 and 4.

Combination C — "Obvious to try" / design-incentive framing (KSR)

A PHOSITA seeking to improve '552 would face a finite number of predictable options: (1) add baffles for mixing; (2) add a metering valve; (3) make the metering valve regulate steam and oil together. KSR authorizes a conclusion of obviousness where there are "a finite number of identified, predictable solutions" and "design incentives and other market forces." A modern court applying KSR would likely find claims 1, 2, 4, and 5 — which recite the combination at a functional level and say nothing about the interior construction that makes the single valve work — obvious over '552 + '124 + Rein or Wood.

But that reasoning collapses at the point of D1's specific structure. Every one of claims 1–6 requires the valve to be hollow with a port to its interior and the chamber to have an annular groove/annular chamber feeding that port. Making a needle valve hollow and feeding it through a circumferential groove in the mating sleeve is not a "predictable variation" of Wood's solid needle valve with a conical seat; it is a different fluid-routing architecture. Nothing retrieved suggests it.

7. Claim-by-claim preliminary view

8. Objective indicia and the case for nonobviousness

A one-sided memo would be malpractice, so here is the other side:

• Long-felt but unresolved need (mild support). Larkin filed '552 in March 1898 and '093 in July 1901 — a three-year continuation of effort on the same problem, which suggests the steam-atomizing art had not already solved mixing and regulation by 1898. That is the classic "long-felt need" narrative, though it is weak without evidence of others' failed attempts.
• The specific architecture has no antecedent. No reference retrieved, pre- or post-1901, shows a hollow valve that doubles as the oil conduit, fed by an encircling wall groove that makes port registration position-independent, with the threaded body serving as the fluid seal between the two inlets. That is a genuinely elegant solution to a real sealing problem — as the art itself acknowledged, needle valves "become worn and cause too large an orifice" and screw threads "eventually become worn out and leaky" (US 335,719).
• Crowded, incremental art. The historical survey retrieved shows burner development proceeding by "well defined steps including distinct types of apparatus." Under pre-1952 practice, narrow improvements in a crowded art were often found patentable — see the contemporaneous interference decision found in search, Blackford v. Wilder (C.C.D.C., Feb. 11, 1903), holding that "the combination of these cooperating elements in the production of a new and useful result" secured patentability and that "it is not admissible to say that one of these elements is subordinate and immaterial." ⚠️ Blackford is a priority decision under § 4904, not a § 103 case; I cite it only as evidence of the era's doctrinal posture, not as controlling authority.
• The 1902 examiner allowed six claims — but that carries almost no weight here, precisely because no prior art appears on the face of the patent and 1902-era searches were far more limited than modern ones. This cuts against the patent's validity, as Sowa indicates.

No evidence of commercial success, copying, or licensing exists in the record — no assignee, no assignment, no litigation, and only one forward citation, which is a 1954 flow-metering valve (US 2,685,294) in a field far removed from oil-burner vaporizers. I found nothing to support those secondary considerations.

9. Bottom line

1. Under a faithful reading of the law applicable to it, US 697,093 was measured against the pre-1952 "invention" standard of Rev. Stat. § 4886, Hotchkiss, and Cuno — not § 103, which did not exist. Any § 103 conclusion is hypothetical.

2. On a modern § 103/KSR standard, claims 1, 2, 4, and 5 are more likely than not obvious over US 609,552 (Larkin) in view of US 275,124 (Blumenberg) and one or both of US 335,719 (Rein) and US 483,885 (Wood) — with the motivation supplied by Larkin's own acknowledgement in '552 that unvaporized oil needed atomizing, and by Blumenberg's express teaching of eddy-mixing in a steam/oil vaporizing chamber.

3. Claims 3 and 6 are the strongest candidates for survival. Claim 3's coupled single-motion shut-off (seat closing simultaneously with port occlusion) has no antecedent in the retrieved art. Claim 6 cannot be assessed at all because its printed text is OCR-damaged.

4. The single most important discovery in this run is US 609,552 — the same inventor's own earlier, more-than-one-year-old patent, which is prior art against him and which the record page does not surface at all. Any serious reexamination of this patent must start there.

5. The combination that would most likely invalidate all six claims does not exist in the retrieved art. A § 103 rejection would have to be built by stitching together '552, '124, '335,719 and '483,885 and then asserting, on KSR "predictable variation" grounds, that making a needle valve hollow and feeding it through a circumferential sleeve groove was within ordinary skill. That assertion is arguable but not self-evident.

10. Data-quality and confidence flags (per the no-fabrication rule)

• The page supplies no verified prior art of record. The "Similar Documents" list is an algorithmic CPC-similarity list, date-blind, and half of it is disqualified. I date-sorted it; the page does not.
• I could not retrieve full text for five pre-1901 references — US 158,316, US 389,322, US 407,632, US 441,467 and US 529,631. The searches for 389,322, 407,632 and 529,631 hit the tool-step limit. I did not infer their disclosures from their titles, and no limitation in this analysis rests on them. Any of the five could contain matter that strengthens or defeats the Combinations above; a definitive opinion requires retrieving them.
• All pre-1901 patent texts here are OCR-derived, with the artifacts typical of the era — e.g., '552's "serai no. 6732359" for the serial number, "iiange" for "flange," "eXterior" for "exterior." I used the numbers only where the surrounding text made them unambiguous and did not silently rewrite them.
• The Priestman "regulates at the same time both the oil and the air supply" passage comes from a 1904 treatise describing an internal-combustion engine. It is post-1901 as a publication and arguably non-analogous art under Potts. I used it as background only and flagged it as such.
• US 483,885 (Wood, 1892) is not on the page's Similar Documents list; it surfaced in a live search. It is properly prior art by date, but I am labelling its provenance so you can see it was not sourced from the page.
• No examiner-cited art, no assignment, no litigation, and no CAFC docket exist for US 697,093 — consistent with the two prior sections.
• My confidence is high on: the 1902/1919 dates, the inventor identity and San Francisco residence, the § 103 non-applicability point, the non-prior-art status of US 2,685,294, the same-inventor identity of US 609,552, and the claim-element mapping. My confidence is moderate on the specific § 103 outcomes in § 7, because they turn on five unretrieved references and on how broadly a court would construe "a port opening into the interior coincident with the oil-inlet passage." I hold no opinion on claim 6, whose text is incomplete.