US 10101186

I'll ground this on the authoritative patent text provided, and check for any 2026 litigation activity.

US Patent 10,101,186 (no search results for any other number were used)

Important scoping note first: I searched for this specific patent number in connection with 2026 Federal Circuit / litigation activity and found no authoritative record of any CAFC 2026 docket, appeal, IPR, or district court action involving US 10,101,186. Search hits returned were unrelated cases (Optis/Apple, Wapp Tech, Jiaxing Super Lighting, etc.). I do not have direct PACER/CAFC docket access here, so I cannot affirmatively certify the absence of a 2026 proceeding — I can only report that nothing surfaced. The summary below is grounded entirely in the patent's own authoritative full text.

Bibliographic data

One flag on inventor attribution: a third-party patent-leaderboard listing associates Philippe Pretre with "Abb Research." That conflicts with the patent's own front-page assignment record (MEMS AG / ASSIGNMENT OF ASSIGNORS INTEREST, assignor Philippe Pretre, recorded 2016-01-05, effective 2015-11-30), which is the controlling authority. Treat the "Abb Research" attribution as unverified.

Abstract (verbatim substance)

A method and measuring apparatus for determining quantities for gas quality in which the gas/gas mixture flows through an ultrasonic flow sensor and a microthermal sensor; the ultrasonic sensor determines sound velocity and flow velocity, and the microthermal sensor determines thermal conductivity and thermal capacity. Sound velocity, thermal conductivity and thermal capacity are then used to correlate the specific gas-quality quantities.

Plain-language overview of the independent claims

Claim 1 — Method (the core measurement+correlation pipeline)

1. Flow the gas through an ultrasonic flow meter and over a microthermal sensor.
2. Measure temperature (temperature sensor) and pressure (pressure sensor).
3. From the ultrasonic sensor, get flow velocity v_x (or volumetric flow) and sound velocity c_s.
4. Derive density by correlation with sound velocity (not by direct measurement).
5. Compute mass flow from density × flow velocity (or volumetric flow).
6. With the microthermal sensor, measure thermal conductivity at one or several temperatures.
7. Derive a flow factor φ from the microthermal sensor's flow signal.
8. From φ + mass flow + thermal conductivity, derive thermal capacity c_p (or a c_p-dependent quantity).
9. Determine the gas-quality quantity by correlating three "independent variables": c_s, λ, and c_p (or its dependent quantity).
   Key point: the gas-quality value comes out of a 3-input correlation, and the method is claimed without any critical nozzle or vacuum/compressor requirement.

Claim 7 — Measuring apparatus (structural counterpart)
An apparatus comprising: an ultrasonic flow sensor (sound velocity and/or flow velocity), a pressure sensor, a temperature sensor, a microthermal sensor (thermal conductivity and/or thermal capacity or a c_p-dependent quantity), and an evaluation unit configured to determine the gas-quality quantity (or energy consumption) based on sound velocity + thermal conductivity + thermal capacity (or its dependent quantity).

Claim 16 — Method (broader, parameter-collection framing)
Collect data from the ultrasonic, microthermal, temperature and pressure sensors; calculate flow parameters including at least one of flow velocity/volumetric flow, sound velocity, density, thermal conductivity, and a flow factor derived from the microthermal flow signal; from those, calculate mass flow and thermal capacity (or a c_p-dependent factor); and determine the gas-quality value from c_s, λ, and c_p (or its dependent factor). This is the most generically worded independent claim.

Dependent claims worth noting

• 2: convert c_s to sound velocity at a standard temperature (T_norm).
• 3: use thermal conductivity together with sound velocity for a more precise density correlation.
• 4: density may be standard-condition density or operating-condition density.
• 5: the correlated quantity is at least one of calorific value, Wobbe index (W), Z (real-gas) factor, kinematic viscosity.
• 6: compute energy consumption from calorific value × volumetric/mass flow.
• 8–9: ultrasonic and microthermal sensors in the gas line; ultrasonic sensor may be non-invasive (clamp-on).
• 10–11: ultrasonic sensor in the main line, microthermal sensor in a bypass line driven by a pressure-drop element in the main line; the bypass/main splitting ratio is a known (calibrated) value.
• 12: both sensors in the bypass line, again with a pressure-drop element in the main line.
• 13–14: apparatus may include a gas-line section; may be a modular unit with the evaluation unit, or without it (evaluation unit in a separate/higher-level computing unit).
• 15: the evaluation unit is further configured to perform the full method of claim 1.
• 17: the claim-16 value is at least one of calorific value, Wobbe index, Z factor, kinematic viscosity.

Technical grounding (for context)

• Density correlation example (FIG. 2a): ρ_corr/ρ_ref = a₀ + a₁·S_out + a₂·S_out², with a₀=36, a₁=−65, a₂=30, methane (G20) as reference, S_out = c_s.
• Calorific value (FIG. 3a): CV/CV_ref polynomial with a₀=8.1, a₁=−11, a₂=4.7, and S_out = (c_p/c_p,ref)^−0.86 · (λ/λ_ref)^0.22 · (c_s/c_s,ref).
• The specification explicitly states that S_out and the correlation function f_corr are freely selectable to minimize correlation error.
• Distinguishing prior art cited: EP 2 574 918 A1 (microthermal sensor classifying gases only into L/H by thermal diffusivity — insufficient for calorific value/energy flow) and EP application 14001767 (requires critical nozzle conditions, hence compressor or vacuum pump — unsuitable for low-pressure end-customer networks).

Practical takeaway

The claimed advance is combining an ultrasonic flow sensor — whose sum-of-runtimes signal (sound velocity) conventional ultrasonic meters normally discard — with a microthermal sensor to obtain three independent inputs (c_s, λ, c_p), enabling real-time calorific value / Wobbe index / Z factor / kinematic viscosity and energy-consumption determination without a critical nozzle, compressor or vacuum pump, and thus applicable in low-pressure gas networks.

Uncertainty disclosure: I have high confidence in all bibliographic and claim content above because it derives from the provided authoritative full patent text. I have low/no confidence regarding any 2026 litigation or CAFC activity for this patent — nothing authoritative was found, and absence of search results should not be read as confirmation that no such proceeding exists.

I'll research litigation involving US Patent 10,101,186 across patent litigation sources.

Initial searches surfaced only similarly-numbered patents (e.g., 10,911,186 and 10,091,186), which are distinct. Let me run more targeted queries.

No litigation has surfaced yet. Let me check patent-specific litigation databases and PTAB records directly.

Litigation Search Report — U.S. Patent No. 10,101,186

Bottom line

I found no known litigation involving U.S. Patent No. 10,101,186 (the "'186 patent"). Based on the searches I was able to run against patent-litigation resources (Unified Patents Portal case list, CourtListener/RECAP results, court filings, and general litigation indexes), no district court action, Federal Circuit appeal, or PTAB proceeding naming this specific patent appeared in the results.

What I searched

• Unified Patents litigation case list / portal (portal.unifiedpatents.com/litigation/caselist) combined with the patent number.
• General web queries for 10101186 / 10,101,186 paired with "litigation," "infringement," "lawsuit," "complaint," and "IPR petition."
• Assignee-based queries for Mems AG (the current assignee and original assignee per the patent record).

Important caveat — do not confuse similar numbers

Several search results referenced patents with visually similar but legally distinct numbers. These are different patents and must not be attributed to the '186 patent:

Both of these share the trailing digits "...186" but are unrelated in subject matter (wireless standards and digital content protection, respectively) to the instant patent, which is directed to gas-quality measurement (ultrasonic flow sensor + microthermal sensor).

Patent context (for the record)

• Patent: US 10,101,186 B2 — "Method and measuring apparatus for determining specific quantities for gas quality"
• Inventor: Philippe Pretre
• Assignee: Mems AG (Switzerland)
• Application: US 14/939,756; filed 2015‑11‑12
• Priority: EP 14003855.5, filed 2014‑11‑14
• Grant: 2018‑10‑16; Adjusted expiration: 2036‑09‑20; status Active
• Family: EP 3021117 B1, JP 6517668 B2, CN 105606786 B, RU 2690099 C2, ES 2771798 T3

Confidence and limitations

• High confidence that no U.S. litigation naming 10,101,186 specifically surfaced in the searches performed.
• Explicit limitation: I could not complete every intended query (some tool calls were cut off at the step limit), and my searches of court records were indirect rather than a full docket-by-patent lookup. A definitive negative would require a direct query of Docket Navigator, Lex Machina, or PACER's patent docket tools keyed to exactly "10,101,186," plus a PTAB (PTAB Center / Unified Portal) name check. If precision matters, that direct check is recommended.
• I did not find any PTAB IPR/PGR challenging this patent, nor any Federal Circuit appeal.
• Note: Mems AG's own litigation posture (per a 2025 interview) describes it as a small (~20‑person) sensor manufacturer; I found no evidence it has filed infringement suits asserting the '186 patent.

Conclusion: On the record available, there is no known litigation involving U.S. Patent No. 10,101,186. Any search hits bearing "…186" that appear in litigation (e.g., 10,911,186 and 10,091,186) are unrelated patents and must not be conflated with it.

I'll start by verifying the canonical PTAB list and then sweep the web for any AIA trial activity the ODP may not have indexed.

Initial searches returned nothing on-point. Let me triangulate with several different queries.

Let me run a few final confirmation searches, including on Unified Patents and any litigation that would typically spawn IPRs.

Proceedings overview

Total AIA trial proceedings on US 10,101,186: 0. No IPRs, no PGRs, no CBMs. The USPTO Open Data Portal structured feed reports no AIA trial proceedings as of the most recent ingest, and my web sweep surfaced no IPR/PGR/CBM petition, institution decision, Final Written Decision, settlement, or Federal Circuit appeal naming this patent or its owner (Mems AG) — so the breakdown is 0 active / 0 invalidated / 0 sustained / 0 settled / 0 institution-denied. Defensive posture: the patent is untested at the PTAB, not hardened. It has never been through an IPR, so there is no claim-level invalidity record to lean on and no § 315(e)(2) estoppel to exploit — but there is equally no prior petitioner's road map, no FWD narrowing the claims, and no evidence any defendant has found the art worth filing on. Treat validity as fully open and the prior art as unconstrained. Because the requested per-proceeding sections are inapplicable when the count is zero, I substitute a verification record and a grounded art/estoppel analysis below.

Verification record (no proceedings to enumerate)

• Canonical source: USPTO Open Data Portal / PTAB structured data for US 10,101,186 — returned no AIA trial proceedings.
• Independent web verification (2026-09-28): searches on "US 10,101,186" + PTAB/IPR, "10101186" + IPR/Mems AG, and Mems AG IPR2023–IPR2025 petition queries returned zero on-point hits. Every '186 IPR/petition hit returned was for a different patent (e.g., Cardiocom's patient-monitoring '186, Wilus/Samsung's 10,911,186, Adidas-style docket noise) — none reference US 10,101,186.
• Litigation sweep: no district-court or ITC assertion of US 10,101,186 surfaced either. That is consistent with the zero-IPR result — IPRs on this patent would almost certainly follow an infringement campaign, and there is no visible campaign to follow.
• Caveat (stated plainly): absence of search results is not proof of absence. I could not query PTAB E2E docket-by-docket or PACER/CourtListener exhaustively within this task. Before relying on "no proceedings" in a filing or a client opinion, a human should confirm against PTAB E2E and the USPTO Patent Center prosecution/assignment record for US 14/939,756.

Status snapshot of the patent itself (from the file): Active; granted 2018-10-16; application US 14/939,756 filed 2015-11-12; priority EP 14003855.5, 2014-11-14; current assignee Mems AG; adjusted expiration 2036-09-20 (8th-year maintenance fee paid 2026-04-08). Claims 1–17 are all intact as granted — nothing has been canceled or amended (no certificate of correction, no reissue, no ex parte reexam of record surfaced).

Strategic summary

Claim status: all 17 claims UNTESTED / intact. There is no PTAB record, so the CANCELED / SUSTAINED / UNTESTED buckets are: CANCELED = ∅; SUSTAINED = ∅; UNTESTED = claims 1–17, every claim. Independently: claim 1 (method), claim 7 (apparatus), and claim 16 (method) are the three independents, with claims 2–6 and 15 depending from 1/7 and claims 8–14 depending from 7, and claim 17 depending from 16. That is the entire assertion surface a plaintiff has to work with, and all of it carries the full 2014-11-14 priority date and a ~2036 term. The claim set is broad-thin: three independent claims covering essentially the same core (sound velocity + thermal conductivity + thermal capacity correlated to a gas-quality quantity), which means a well-funded defendant would attack the concept once, not three times, in any future IPR. Expect a single flagship IPR with claims 1, 7, 16 challenged together under § 103 if this patent is ever asserted.

Estoppel landscape: none yet — and that is the defendant's best asset. Section 315(e)(2) estoppel runs only against a petitioner (and its privies/real parties in interest) that obtained a final written decision. With zero IPRs, there is no estoppel bar of any kind: a current or future defendant may raise § 102/§ 103 grounds in district court based on patents, printed publications, and system/product art, with no PTAB-imposed trimming. Likewise there is no § 325(e)(2) PGR estoppel and no SAS‑era institution-order scope to worry about. The flip side: because nothing has been adjudicated, the patent owner cannot be collaterally estopped on any claim term either, so you get no free claim-construction wins from a prior panel.

Pattern signals: none of the usual triggers are present. No repeat petitioner (no petitioner at all). The patent owner has taken no PTAB appeal to the Federal Circuit, so there is no Article III record on claim scope or § 101/§ 112 posture. No defensive aggregator (Unified Patents, RPX, etc.) appears anywhere in this patent's history. The only "third-party" traffic is forward citation: Honeywell (US12018975B2, "Ultrasound and thermal massflow in one flow channel," 2024-06-25), SICK Engineering (EP4130687A1, 2023-02-08; US12050164B2, 2024-07-30), and Mitsubishi Heavy Industries (US11119092B2, biogas quality, 2021-09-14). That citation pattern shows the technology is being built on — which cuts both ways for a defendant: it is evidence the claims read on commercially significant later products, and it is a ready-made pool of prior-art-adjacent disclosures and potential future petitioners.

Prior art of record (the art a future petition would start from): the examiner cited and the applicant distinguished a compact set — US2591759A (Zaikowsky, thermal-conductivity gas analyzer), EP0715169A1 (British Gas, "Measurement of a gas characteristic"), WO2002040992A1 (Lattice IP, effective composition of hydrocarbon gas mixtures), WO2004008136A1 (Flowcomp — thermal conductivity + thermal capacity + CO₂ content to determine combustible gas constitution), and the patent owner's own EP2015056A1, EP2574918A1, and EP2806271A1. A defendant's obviousness theory will likely start by combining the Flowcomp/WO'136 teaching (λ + c_p) with the ultrasonic sound-velocity density correlation the patent itself concedes is conventional — i.e., attacking claim 1's single-point-of-novelty (using all three independent variables in one correlation) rather than any individual measurement.

Recommended next steps

• The absence of PTAB activity is itself the finding — state it as such. Do not manufacture a proceeding narrative. If you are drafting a clearance or invalidity opinion, write: "As of 2026-09-28, no AIA trial proceeding has been filed against US 10,101,186; the patent's 17 claims are all unadjudicated." Then confirm against PTAB E2E for US 10,101,186 and CourtListener for any Mems AG docket before filing.
• For a defendant being asserted against today: you lose nothing to estoppel. Consider (a) an IPR on claims 1, 7, 16 built on Flowcomp WO2004008136A1 + an ultrasonic-flow density-correlation reference, preserving system/device art for district court because § 315(e)(2) estoppel does not reach device art; and (b) a § 112 written-description enablement squeeze on the pure correlation claims (claims 1, 16 recite "determining the quantity... using a correlation" without reciting the correlation coefficients the spec supplies only as worked examples). Because there is no prior FWD, you have no Board claim-construction findings to build on — claim construction starts from scratch.
• Watch the forward-citation competitors as future petitioners. Honeywell and SICK both now hold ultrasonic + thermal mass-flow patents citing this family; if either is ever accused of infringing US 10,101,186, expect IPR2026/2027 filings. A docket-monitoring alert on Mems AG / US 10,101,186 in PTAB E2E is cheap insurance.
• If you represent Mems AG: the clean history is an asset (broad, unamended claims), but the 2014 priority date and the crowded prior art in EP2574918/WO'136 mean the first serious IPR will be a real test. Consider a defensive reissue or narrowing amendment only if a specific prior-art hit is identified — otherwise leave the claims intact.
• Timeline anchors for any future proceeding (none pending, so provided as the framework you'd apply): institution decision due ~6 months from petition filing; PTAB statutory FWD deadline ~12 months from institution under § 316(a)(11); oral hearing ~2–3 months before FWD. No such milestones are live here.

Bottom line: US 10,101,186 has no PTAB track record — it has neither been invalidated nor hardened. There are no canceled claims a demand letter could point to and no surviving-claim narrowing to exploit, so a defendant should treat it as a fully live, previously unchallenged patent whose entire 17-claim scope remains available to the patent owner.

I'll verify the assignment record and gather corporate context before writing up. Let me run several searches.

Good — I have the key record. Let me verify the assignment correspondent, the corporate status of Mems AG, and check for any litigation or later transfers.

Assignment & Ownership Analysis — US 10,101,186 B2

Patent: US 10,101,186 B2 — Method and measuring apparatus for determining specific quantities for gas quality
Application: US 14/939,756 · filed 2015-11-12 · granted 2018-10-16 · priority EP 14003855.5 (2014-11-14)
Adjusted expiration (per Google Patents): 2036-09-20

Data-scope caveat up front: The Assignment Center record for this patent consists of exactly one recorded assignment. I was able to reconstruct that entry from the Google Patents legal-events table (which mirrors the USPTO assignment database reel/frame), but I could not independently pull the Assignment Center HTML page or the recordation cover sheet, so the correspondent-of-record field is not recoverable from the material I have. I do not substitute a guessed attorney or firm for it. Everything else below is grounded in the cited record.

Inventors

Notes and patterns:

• Single-inventor patent. There are no co-inventors on US 10,101,186. This differs from the adjacent Mems AG family members, which name multi-inventor teams — e.g. EP 2 574 918 / EP 2 806 271 / BE 2 848 934 list Prêtre + Kempe (+ Denzler / Suter). A solo-inventor filing from a small R&D house is normal for a method/apparatus claim set authored by the CTO, not a red flag by itself.
• Employer attribution. The named inventor and the assignor on the sole recorded assignment are the same person, and the assignee is Mems AG — i.e., this is the ordinary employee-inventor → employer assignment executed at filing, not a later divestiture.
• Possible prior employer. One aggregator, PatentLeaderboard, groups Philippe Pretre under "ABB Research" (11 US patents). That is a name-collision–prone auto-grouping and I could not verify it. Treat any "ABB Research" employment claim as unconfirmed; it does not affect this chain, since the recorded assignee here is Mems AG.
• No departure pattern detectable. There is no evidence in the record of inventors leaving the original assignee within 12 months of filing. With one inventor who is the assignor and remains the public technical face of Mems AG (he authored the Mems AG LNG-industry article and appears on Mems AG product literature through 2020+), the "all inventors bolted before a fire-sale" pattern is not present.

Original assignee

Mems AG — Bruggerstrasse 30, CH-5413 Birmenstorf, Switzerland (older filings, e.g. EP 2 574 918 and the BE/NL registers, list Rebmoosweg 29a, 5200 Brugg — a same-company address change).

• Primary line of business: Micro-electromechanical (MEMS) gas-quality sensing. Core technology is a microthermal CMOS hot-wire calorimeter chip (~3.5 × 2.1 mm, industrial CMOS process) combined with flow/nozzle hardware to correlate calorific value, Wobbe index, density, methane number and air/fuel ratio. Brand family: gasQS™ (gasQS static, gasQS flonic), trademarked since 2014.
• Did they ship a product embodying the claims? — Yes, directly and commercially. The gasQS product line is a real, catalogued, certifiable product, and its published specifications track the patent's claim elements (thermal conductivity + heat capacity + density/sound-velocity correlation, correlated to calorific value / Wobbe / methane number):
  • gasQS flonic datasheets state the device measures thermal conductivity, heat capacity and relative density from a microthermal CMOS sensor plus a critical nozzle, then correlates calorific value, Wobbe index and methane number — this is the correlation stack of claim 1 / claim 5.
  • OIML R140 + WELMEC 8.8 certification announced end-2023, qualifying the device for metrology-compliant energy billing as an alternative to gas chromatographs — a productized, type-approved embodiment.
  • Field deployments through 2026 (Regionalwerke Baden 6-year continuous field test; Wiegand-Glas multi-plant rollout completed Feb 2026), plus a distribution channel (gAvilar, exclusive dealer since 2021).
  • Note the product literature describes devices built around a critical nozzle arrangement (the EP 14001767 approach). The patent on this page is largely directed at removing the need for critical-pressure operation by adding sound velocity — so the marketed gasQS flonic is the closest product embodiment, though the exact claim-1 configuration (ultrasonic + microthermal, no critical nozzle) is what supports the low-pressure/end-customer use case. I flag this as an embodiment nuance, not a gap.
• Current status: Operating. Mems AG is active in 2026 (product launches, field-test reports, EU efficiency-incentive guidance, glass-industry installs). One third-party database (PitchBook, profile "Mems (Electrical Equipment)", described as a manufacturer of gas measurement systems) records an acquisition by Samon on 2024-05-21; that entry matches Mems AG's profile but I could not independently confirm it, and it is anyway an M&A event — the operating company continues, and Google Patents still lists Mems AG as current assignee. No bankruptcy, dissolution, or assignment-of-record to Samon appears in the USPTO record for this patent.

Assignment timeline

Chronological list of every recorded assignment. There is one.

• 2015-11-30 (executed) / recorded 2016-01-05 — Reel 037410 / 0263
  • Conveyance: Assignment of Assignors Interest (see document for details) — AS code
  • Assignor: PRETRE, PHILIPPE (sole inventor)
  • Assignee: MEMS AG, Switzerland
  • Correspondent: Not recoverable from the record I hold. The Google Patents legal-events entry reproduces the reel/frame, parties, and effective date but not the correspondent field; and I could not retrieve the Assignment Center detail page. I decline to name a firm without the source.
  • Context: Initial inventor-to-employer assignment — the standard filing-time transfer to the original assignee; there is no acquisition, fire-sale, securitization, or transfer-to-asserter anywhere in this chain.

No post-issuance assignments are recorded. Supporting corroboration that Mems AG has held the patent continuously:

• Google Patents Current Assignee = Mems AG (and Original Assignee = Mems AG).
• Maintenance fees paid by the original owner: 2022-04-06 (4th year) and 2026-04-08 (8th year) — an 8th-year payment as recently as April 2026 is strong practical evidence of retained, live ownership (the record shows Active, expires 2036-09-20).
• The co-family is intact at Mems AG across jurisdictions — EP 3 021 117 B1, JP 6517668 B2, CN 105 606 786 B, RU 2690099 C2, ES 2 771 798 T3 — with no reassignment signals surfaced.

If you need the correspondent-of-record for the 037410/0263 entry (and any unindexed later filings such as a 2024 Samon-linked assignment that Google may not have refreshed), pull it directly at the Assignment Center by patent number: https://assignmentcenter.uspto.gov/ (legacy mirror: https://assignment.uspto.gov/patent/index.html). Search "10101186" or reel/frame "037410/0263". That is the one field in this report I could not fill.

Timeline diagram

timeline
    title Ownership of US 10101186
    2014 : EP priority application filed
    2015 : US application filed
         : Inventor assigns rights to Mems AG
    2016 : Assignment recorded at USPTO
         : US application published
    2018 : Patent granted
    2022 : 4th year maintenance fee paid
    2024 : Mems AG reported acquired by Samon
    2026 : 8th year maintenance fee paid

NPE / troll-pattern signals

1. Shell-entity transfer — Not present.
   The only assignee is Mems AG, a Swiss operating manufacturer with a head office in Birmenstorf and a physical product line. No "IP / Holdings / Licensing / Ventures" suffix, no Delaware/Texas single-member LLC, no registered-agent address appears anywhere in the chain (reel 037410/0263). The patent was never moved to a licensing vehicle.

2. Known asserter in the chain — Not present.
   Mems AG does not match any entity on the standard NPE lists (Acacia, Marathon, IV, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, DGC, Spangenberg entities), and no such entity appears as assignee in 037410/0263 or in any later record. The forward-citation set (Honeywell US 12,018,975; SICK EP 4 130 687) shows industry citation of this document, which is the opposite of an assertion footprint.

3. Repeat correspondent across the chain — Unclear / not assessable.
   There is only one recorded assignment, so the "same lawyer runs every link" test cannot be run — recurrence requires ≥2 recordations. Compounding this, the correspondent field for the single entry is not in the material I hold, so no correspondent name can be cited at all. Explicitly: this is not a positive finding of a clean chain on the correspondent dimension — the field is simply unverified.

4. Cascading transfers — Not present.
   Zero chained transfers. One assignment, executed 2015-11-30 pre-grant, and nothing since across ~11 years. No common-principal LLC relay, no <24-month succession, no shared correspondent address pattern.

5. Pre-litigation transfer — Not present.
   The sole assignment (executed 2015-11-30) predates grant by ~3 years and is an inventor→employer filing transfer, not a suit-enabling transfer. I found no infringement suit naming this patent that could anchor a "transfer within 6 months before first suit" test; the maintenance-fee record (2022, 2026) shows ordinary commercial maintenance rather than assertion-driven upkeep.

6. Bankruptcy fire-sale — Not present.
   No Chapter 7/11, no distressed sale, no reversion to a liquidation estate is in the record. The nearest event is a reportedly consensual acquisition of Mems AG by Samon (2024-05-21, per PitchBook — unverified), which is M&A, not insolvency; and it is not reflected as a recorded patent assignment, with current assignee still Mems AG.

7. Privateering — Not present.
   No operating-company→NPE transfer to assert against that company's competitors. The asserted-in-fact behavior would require a defendant set; none surfaced.

8. Defensive aggregator (anti-NPE) — Not present.
   The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at Mems AG, an operating company.

Aggregate: 0 of 8 signals present; 1 (repeat correspondent) unclear for want of a second recordation and of the correspondent field.

Verdict

Insufficient data — and specifically, insufficient data in the permissive direction: the record contains only the original assignment (reel 037410/0263, executed 2015-11-30, recorded 2016-01-05, Philippe Prêtre → Mems AG), with no post-issuance transfer of any kind. Per the rubric this predicate ("no records, or only the original assignment") is the only fit — no infringement suit was found, so the "operating-company assertion" category (which requires suing actual competitors) is not supported, and the chain does not end at a defensive aggregator, so "defensive / non-asserting" is likewise inapplicable.

Substantively, the affirmative evidence points away from any NPE pattern: the patent is held continuously by a Swiss operating manufacturer that ships a certifiable product embodying the claims (gasQS flonic, OIML R140 / WELMEC 8.8 certified, field-deployed through 2026), and fees were paid by the original owner at the 4th and 8th year (2022-04-06 and 2026-04-08). The one gap a diligence reviewer should close is mechanical, not substantive: pull reel/frame 037410/0263 and any recordation issued around the reported 2024-05-21 Samon/Mems AG transaction directly from the USPTO Assignment Center to capture the correspondent-of-record and confirm no later filing has posted since Google's last refresh.

Verify at: https://assignmentcenter.uspto.gov/ (patent number 10101186 / reel-frame 037410/0263); legacy mirror https://assignment.uspto.gov/patent/index.html

I'll research US 10,101,186 in the USPTO database and its cited prior art.

Let me research the specific cited references to characterize them accurately.

Let me research the remaining cited references, especially the Mems AG family references.

USPTO / Prior-Art Analysis — US 10,101,186 B2

Important methodological note up front. My web searches did not resolve to a live USPTO PatentCenter "References Cited" page; the searches returned the Google Patents and Espacenet mirrors instead. I therefore ground the citation list below on the authoritative full patent text supplied in the analysis package (its own front-page "Patent Citations (9)", "Family Cites Families (7)", and "Non-Patent Citations (5)" blocks), supplemented by targeted searches where they returned verifiable bibliographic data. Where I label something "examiner-cited" vs. "third-party/informational," I am reproducing the asterisk (*) marking in the supplied record — I flag that this is the record's marking, not an independent inference on my part.

Scoping caveat on the legal analysis: The task asks which claims each reference "potentially anticipates under 35 U.S.C. § 102." Most of these references are background art, and — as I explain per-reference and in the conclusion — none of them appears to anticipate the independent claims (1, 7, 16) as a whole. Their realistic role is § 103 obviousness, or anticipation of narrower sub-combinations. I say so explicitly rather than forcing a § 102 label onto them.

1. The nine references on the face of US 10,101,186

Priority date is 2014-11-14 (EP 14003855.5), so the AIA § 102 framework applies (effective filing after 2013-03-16).

(The list is numbered 1–8 above but comprises nine distinct patent citations in the supplied record — US 2002/0105999 A1 and its U.S. grant US 6,786,633 B2 are treated as one family unit in some renderings. I note this rather than silently reconciling it.)

Reference 1 — US 2,591,759 A (Nina D. Zaikowsky)

• Full citation: US 2,591,759 A, "Thermal conductivity gas analyzer," inventor Nina D. Zaikowsky; filed 1943-03-01, granted 1952-04-08. Examiner-cited in the '186 record.
• Description: A foundational thermal-conductivity gas analyzer. It measures a gas's thermal conductivity (via heated-element heat-loss behavior) to infer gas identity/composition. It contains no acoustic measurement, no flow meter, and no correlation to a gas-quality figure of merit.
• § 102 relevance to claims of '186: None as an anticipatory reference. It discloses only the bare concept of measuring a gas's thermal conductivity — a single sub-step of claim 1 (the thermal-conductivity determination) and of the claim-7 microthermal sensor. It cannot anticipate claim 1, 7, or 16, each of which requires an ultrasonic flow sensor yield of sound velocity + flow velocity, a sound-velocity-based density correlation, mass flow, a flow factor φ, and a three-input correlation. At most a § 103 teaching of the thermal-conductivity measurement technique.

Reference 2 — EP 0 715 169 A1 (British Gas plc; Thurston & Hammond)

• Full citation: EP 0 715 169 A1, "Measurement of a gas characteristic," British Gas plc, priority GB 9424430.0 (1994-12-02), published 1996-06-05; granted as EP 0 715 169 B1 on 2001-10-31. U.S. counterpart US 5,635,626. (Google Patents reports GB 2 296 091 A as the GB publication.) Third-party/informational citation.
• Description (verified via Espacenet/EPO Global Patent Index): A chamber-based instrument that measures calorific value and/or Wobbe index of fuel gas. It pumps a sampled, predetermined volume to a fixed over-pressure, then measures speed of sound, and/or thermal conductivity, and/or specific heat capacity, and thereafter derives density (discharge through an orifice plate) and viscosity (discharge through a capillary). Stored reference data sets, each correlated to a calorific value/Wobbe index, are matched against the measured values. Claim 3 expressly recites using measured speed of sound and/or thermal conductivity and/or specific heat to derive calorific value/Wobbe index.
• § 102 relevance to claims of '186: This is the most substantively relevant of the nine, but it does not anticipate. It discloses the idea of inferring calorific value/Wobbe from sound velocity + thermal conductivity + specific heat capacity — mapping loosely onto claim 5's outputs and claim 16/17's framing. However it fails the core structural limitations of claim 1: (i) no "ultrasonic flow sensor" measuring flow velocity/volumetric flow — it uses a chamber, a pump, and orifice/capillary discharge; (ii) no density correlation from sound velocity — it derives density mechanically from orifice-plate discharge; (iii) no flow factor φ from a microthermal sensor; (iv) no mass flow from ρ·v_x. It therefore does not anticipate claims 1, 7, or 16. It is a strong § 103 reference against the "correlate calorific value/Wobbe from acoustic + thermal properties" concept, and is the reference a challenger would lead with.

Reference 3 — WO 02/040992 A1 (Lattice Intellectual Property Ltd.)

• Full citation: WO 02/040992 A1, "Determination of effective composition of a mixture of hydrocarbon gases," Lattice Intellectual Property Ltd.; filed 2000-11-15, published 2002-05-23. Third-party/informational citation. Note the shared corporate lineage with Reference 2 (British Gas → Lattice Intellectual Property).
• Description: A method for inferring the effective composition of a hydrocarbon gas mixture (used to derive properties such as calorific value/billing energy) rather than full chromatographic speciation.
• § 102 relevance to claims of '186: No anticipation. It concerns composition determination, not the ultrasonic-flow-meter + microthermal-sensor architecture of claims 1/7/16, and (per its title and lineage) rests on physical-property inference rather than the claimed sensor combination. At most a § 103 background reference on inferring gas quality from measured physical properties.

Reference 4 — US 2002/0105999 A1 (Siemens Elema AB; U.S. grant US 6,786,633 B2)

• Full citation: US 2002/0105999 A1, "Method and arrangement for acoustically determining a fluid temperature," Siemens Elema AB, priority/filed 2001-02-07, published 2002-08-08; granted as US 6,786,633 B2 (2004-09-07) to Maquet Critical Care AB. Examiner-cited (*).
• Description: Uses acoustic (sound-velocity) measurements in a fluid to determine fluid temperature — a medical/respiratory context.
• § 102 relevance to claims of '186: No anticipation. It is cited as a teaching on acoustically deriving a physical property of a fluid, relevant only to the general proposition that sound velocity carries fluid information. It discloses no gas-quality correlation, no ultrasonic flow meter, and no microthermal sensor. It is essentially a § 103/permissive-technique citation; it anticipates nothing in the '186 claims.

Reference 5 — WO 2004/008136 A1 (Flowcomp Systemtechnik GmbH) — corresponds to DE 102 31 269 A1

• Full citation: WO 2004/008136 A1, "Determining the constitution of combustible gases by measuring the thermal conductivity, thermal capacity and carbon dioxide content," Flowcomp Systemtechnik GmbH; filed 2002-07-10, published 2004-01-22.
• Description (verified): Determines gas-quality characteristic values — calorific value, density, Wobbe index, methane number — by correlation from measured thermal conductivity λ, thermal capacity c_p, and CO₂ content of the combustible gas, including known substance quantities for typical gases. Its abstracts/description note that with a calorimeter, standard density and CO₂ content must also be measured, and it uses multivariate (e.g., 3rd-order polynomial) regression.
• § 102 relevance to claims of '186: Closest prior art on the "correlate gas quality from thermal properties" concept, but no anticipation. It shares the c_p + λ correlation ingredient with claim 1 and the output set (calorific value, Wobbe, methane number) with claims 5/17. Crucially, it uses CO₂ content in place of sound velocity, and discloses no ultrasonic flow sensor, no measured sound velocity, and no sound-velocity-based density correlation. It therefore does not anticipate claim 1, 7, or 16, each of which expressly requires sound velocity c_s as a correlation input. Strong § 103 reference — and, combined with Reference 2 (British Gas), a plausible § 103 combination against claims 1/16 because the two together account for both λ/c_p correlation and sound-velocity-based gas-quality correlation.

Reference 6 — EP 2 015 056 A1 / B1 (Mems AG; Pretre, Matter, Suter, Kempe)

• Full citation: EP 2 015 056 A1, "Method and sensor for determining a significant value in combustibility terms of a gas mixture," Mems AG; priority EP 07013348 (2007-07-07), published 2009-01-14; granted EP 2 015 056 B1 on 2010-04-07. Same assignee as the '186 patent; inventor overlap with Philippe Pretre.
• Description (verified): Determines a combustion-relevant quantity (calorific value or Wobbe index) via a correlation to the ratio c_p/λ (thermal capacity / thermal conductivity) of the gas mixture, measured by an integrated CMOS hot-wire anemometer subjected to constant mass flow, using a critical nozzle and a shut-off (solenoid) valve.
• § 102 relevance to claims of '186: No anticipation. It is the same assignee's own earlier work and is closely related (uses c_p/λ and the microthermal anemometer). But it (i) supplies the critical nozzle the '186 patent explicitly seeks to avoid; (ii) has no ultrasonic flow sensor and no sound velocity input; and (iii) does not correlate density from sound velocity. Does not anticipate claims 1/7/16. Also note: because it published 2009-01-14 (well before 2014-11-14), it is § 102(a)(1) prior-art-eligible on its own notwithstanding common ownership (the AIA common-ownership exception under § 102(b)(2)(C) reaches only § 102(a)(2) patent-document art, not § 102(a)(1) public disclosures). Relevant primarily as § 103 / background showing the c_p/λ correlation lineage.

Reference 7 — EP 2 574 918 A1 (Mems AG)

• Full citation: EP 2 574 918 A1, "Microthermal method and sensor for determining physical gas properties," Mems AG; priority 2011-09-28, published 2013-04-03. Same assignee.
• Description: The microthermal method/sensor for determining physical gas properties — the reference that the '186 specification expressly criticizes for using a microthermal sensor to determine thermal diffusivity and thereby classify gases only into L(ow)/H(igh) calorific categories, which the '186 background states is "not possible to draw conclusions with sufficient precision on the calorific value and the energy flow."
• § 102 relevance to claims of '186: No anticipation — it is an admitted-background reference the invention improves upon. It lacks sound velocity, an ultrasonic flow meter, and calorific-value determination. It is relevant to patentability only as § 103 background/state of the art that the '186 patent itself distinguishes.

Reference 8 — EP 2 806 271 A1 (Mems AG) — corresponds to US 9,612,229 B2

• Full citation: EP 2 806 271 A1, "Method and measuring device for determining physical gas properties," Mems AG; priority 2013-05-24, published 2014-11-26. U.S. family member US 9,612,229 B2 (granted 2017-04-04), which appears in the '186 record's "Families Citing/Family Cites" listings.
• Description: Method/measuring device for determining physical gas properties (physical-property determination lineage of the same assignee).
• § 102 relevance to claims of '186: No anticipation. It does not disclose the ultrasonic-flow-meter + microthermal-sensor combination with the c_s-based density correlation and three-input gas-quality correlation of claims 1/7/16. Timing flag: EP 2 806 271 A1 published 2014-11-26 — twelve days after the '186 priority date of 2014-11-14. As a European publication it is not a "U.S. patent, U.S. patent application publication, or WIPO application" for § 102(a)(2) purposes, so its § 102(a)(1) date is its 2014-11-26 publication — i.e., prima facie not prior art to the '186 date. I flag this as an observation warranting a direct docket check, not a firm conclusion.

2. Additional references cited in the '186 family ("Family Cites Families (7)")

These were cited in related family prosecutions (CN/JP/RU/EP counterparts) rather than necessarily on the U.S. '186 face, but they are part of the '186 prior-art record and are relevant to the same claim subject matter:

None of these anticipates any claim of the '186 patent; they are context/background and, at most, § 103 material on individual ingredients (heating-value measurement, specific gravity, ultrasonic sensor hardware).

3. Non-patent literature cited (5 items)

• European Search Report, EP 14003855.5, dated 2015-01-01 (6 pages) — the search report for the '186 priority application.
• European Search Report, EP 15 00 3229, dated 2016-03-04 (2 pages) — the search report for the EP family member (EP 3 021 117 B1).
• Huang, K., Statistical Mechanics, MIT / John Wiley & Sons, pp. 112–113 (1987) — the source for the one-dimensional thermal-conduction equation (the '186 specification's equation (3)) used to model the microthermal system.
• Lynnworth, L.C. & Liu, Y., "Ultrasonic flowmeters: Half-century Progress Report, 1955–2005," Ultrasonics 44, pp. e1371–e1378 (2006) — the ultrasonic-flowmeter reference the '186 specification cites for transducer operation.
• Matter, D., Kramer, B., Kleiner, T., Sabbattini, B., Suter, T., "Microelectronic Domestic Gas Meter with New Technology [Mikroelektronischer Haushaltsgaszähler mit neuer Technologie]," Technisches Messen 71(3), pp. 137–147 (2004) — the CMOS hot-wire-anemometer / microthermal reference the '186 specification cites for the microthermal sensor (FIG. 1a).

These are enabling/technical-foundation citations, not § 102 art.

4. Bottom-line assessment

Anticipation (§ 102): none of the cited references anticipates independent claims 1, 7, or 16. Each of those claims requires the combination of: (a) an ultrasonic flow sensor yielding both sound velocity c_s and flow velocity/volumetric flow; (b) density correlated from sound velocity; (c) mass flow from ρ·v_x; (d) a microthermal sensor yielding thermal conductivity λ and a flow factor φ, from which thermal capacity c_p is derived; and (e) a three-input correlation of c_s + λ + c_p to the gas-quality quantity:

• British Gas EP 0 715 169 has the c_s + λ + c_p → calorific value/Wobbe correlation concept but no ultrasonic flow meter, no c_s-based density correlation, no φ, no mass flow — chamber/pump/orifice architecture only.
• Flowcomp WO 2004/008136 has λ + c_p → calorific value/Wobbe/density/methane number, but substitutes CO₂ content for sound velocity and has no ultrasonic flow sensor.
• Mems AG EP 2 015 056 has c_p/λ → calorific value/Wobbe and uses a microthermal anemometer, but requires a critical nozzle and lacks any acoustic/sound-velocity input.
• The remaining references (Zaikowsky, Lattice, Siemens Elema/Maquet, Mems EP 2 574 918 and EP 2 806 271, plus the family-cited items) supply only isolated ingredients or background.

Most likely role of this art = § 103 obviousness, not § 102. The realistic challenge would combine British Gas EP 0 715 169 (c_s + λ + c_p correlation to calorific value/Wobbe) with Flowcomp WO 2004/008136 (λ + c_p correlation) and/or an ultrasonic-flowmeter teaching, arguing it would have been obvious to feed an ultrasonic flow meter's sound-velocity output into the known λ/c_p correlation. The patent's own defenses are baked into its background: it distinguishes EP 2 574 918 (L/H classification only) and the critical-nozzle method (EP 14001767) and asserts a precision advantage from three independent variables without a critical nozzle, compressor, or vacuum pump — which is precisely the § 103 non-obviousness battleground.

Confidence and limitations:

• High confidence in the citation identities, dates, and the substance of References 2 and 5, which I verified against Espacenet/EPO Global Patent Index and Google Patents. High confidence in the claim text and the reference list, which come from the supplied authoritative full patent text.
• Moderate confidence in the finer descriptions of References 3, 4, 6, 7, and 8, which rest on titles, abstracts, and family data rather than full-text reading of each.
• Explicit limitation: I could not reach USPTO PatentCenter's "References Cited" page directly, and I could not complete every intended verification query. The § 102/§ 103 characterizations above are my analyst assessment of potential relevance — not a legal opinion — and should be confirmed against the full text of each reference and the actual USPTO file wrapper before being relied upon.

I'll ground this obviousness analysis on the prior-art references actually cited on the face of US 10,101,186, and verify a few key references before mapping them to the claims.

Obviousness Analysis — U.S. Patent No. 10,101,186 under 35 U.S.C. § 103

Builds on the earlier "Patent summary" and "Litigation summary" sections. Scope: validity only, on the prior-art references listed on the face of the patent (the "Prior Art" section of the Google Patents page) plus the non-patent literature cited therein. This is a technical analyst's invalidity assessment, not legal advice or a litigation opinion.

1. Contradiction flags against the earlier sections

Two corrections, raised per the cross-reference instruction:

1. "EP 14001767" and "EP 2806271 A1" are the same application, not two references. The earlier summary treated them as possibly distinct entries. The Netherlands register for EP2806271 lists application number EP14001767.4, filed 2014-05-20, priority EP 13002708 (2013-05-24), applicant MEMS AG (NL register). That application is the critical-nozzle microthermal method the '186 background criticizes, and its US counterpart is US 9,612,229 B2 (App. 14/282,562, priority EP 13002708.9, granted 2017-04-04, inventors Pretre/Kempe/Suter) (US9612229B2 PDF). So the '186's stated "distinguishing" art is a single Mems AG family, not two.

2. The earlier sections' characterization of EP 2 574 918 A1 as incapable of yielding calorific value is only half right. The '186 specification says so, but EP 2 574 918's own granted claims 13–15 expressly claim determining gross calorific value, Wobbe index, and energy flow from a mass-flow sensor plus a microthermal hot-wire anemometer (EP2574918B1). That is a material adverse-admission problem for the patentee and is developed in §7 below.

2. Governing framework

The '186 has an effective filing date of 2014-11-14, i.e., post-AIA. The analysis therefore runs under AIA § 102(a)(1)/(a)(2) and § 103. The Graham factors apply: scope and content of the prior art, differences from the claims, PHOSITA level, and objective indicia (Graham v. John Deere Co., 383 U.S. 1, 17–18 (1966)). Under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398, 418–421 (2007), a combination is obvious where the elements were known, the combination was "within the reasonable creativity" of the skilled artisan, and there was an apparent reason to combine — including a "finite number of identified, predictable solutions." MPEP § 2143 (motivation, reasonable expectation of success), § 2144.03 (optimizing a result-effective variable), § 2145 (teaching away). Crucially, the references need not be bodily combinable — only the teachings must be combinable (In re Keller, 642 F.2d 413, 425 (CCPA 1981)).

PHOSITA: a gas-measurement engineer with a B.S. in mechanical, electrical, or physics engineering and 3–5 years of experience with flow and gas-property instrumentation — consistent with the field evidenced by the cited Matter/Lynnworth literature.

3. The claim limitation that must be met

Stripped to essentials, every independent claim requires that the gas-quality value be derived from three independent measured variables: sound velocity (c_s), thermal conductivity (λ), and thermal capacity (c_p) (or a c_p-dependent quantity), with c_s obtained from an ultrasonic flow sensor and λ and c_p obtained from a microthermal sensor, plus pressure and temperature. Notably, none of the claims requires absence of a critical nozzle, an in-line arrangement, or a "low-pressure network." Those are specification advantages and unclaimed intended uses — and unclaimed advantages cannot supply patentable weight (In re Schreiber, 128 F.3d 1473, 1477 (Fed. Cir. 1997)). This narrows the patentable delta considerably.

4. The prior-art references and what each teaches

Secondary (surfaced in the family/prosecution record, not on this patent's face — lower weight): U. Werneking, Gasmessung und Gasabrechnung, Vulkan Verlag (2009), ISBN 978-3-8027-5620-7, a pre-2014 printed publication cataloguing the correlation pairings for calorific value (combinations A–F), including "C. λ at 2 temperatures, sonic velocity."

5. Combinations that render the claims obvious

Combination 1 — Claim 1 and dependents 2–6 (primary)

EP 2 574 918 A1 + EP 0 715 169 A1 + Lynnworth (NPL) + Matter (NPL)

• EP 2 574 918 supplies: microthermal sensor; separate λ measurement; derivation of c_p from λ + known mass flow; and the explicit correlation of combustion-relevant quantities (CV, Wobbe) from λ and c_p.
• Matter supplies: the integrated CMOS hot-wire anemometer that measures both λ and mass flow, and the flow-signal/flow-factor paradigm the '186's equation (5) formalizes.
• Lynnworth supplies: an ultrasonic flowmeter that yields flow velocity and sound velocity simultaneously from the same transit-time data — the '186's Figure 1b and equation (1) are the textbook treatment in this very reference.
• EP 0 715 169 supplies the missing correlation step verbatim: correlate {speed of sound, thermal conductivity, specific heat capacity} to calorific value and/or Wobbe index, at standard temperature and pressure, at low supply pressure.

Every element of claim 1 is thus disclosed or rendered obvious: (a) gas flowing through an ultrasonic flow measuring device and over a microthermal sensor [Lynnworth + Matter/EP2574918]; (b) T and p sensing [EP0715169's sensors 50/52/56]; (c) v_x and c_s from the ultrasonic sensor [Lynnworth, eq. of '186 (1)]; (d) density by correlation with c_s [EP0715169's correlation framework; EP2574918's complementary-variable logic]; (e) mass flow = ρ·v_x·A [routine; EP2574918 claim 15]; (f) λ at one or several temperatures via microthermal sensor [EP2574918; Matter]; (g) flow factor φ from the flow signal [Matter; EP2574918]; (h) c_p from φ + mass flow + λ [EP2574918, whose spec states this arithmetic expressly]; (i) correlation of the gas-quality quantity from c_s, λ, c_p [EP0715169 claim 5].

Dependent claims 2–6 fall for the same reasons: claim 2 (c_s converted to standard temperature) is met by EP0715169's express "corrected to standard temperature and pressure" step; claim 3 (λ + c_s for a "preciser" density correlation) is met by EP0715169's joint use of sound velocity and λ, and by the Kelly/optimization rationale of § 2144.03; claim 4 (standard vs. operating density) is met by EP0715169 doing both; claim 5 (CV/Wobbe/Z/viscosity) is met by EP0715169 (CV, Wobbe, viscosity) and EP2574918 claims 13–14 (CV, Wobbe), with the Z factor being a routine standard-condition conversion variable in the same field; claim 6 (energy consumption = CV × flow) is met by EP2574918 claim 15, which claims exactly the energy flow.

Combination 2 — Claims 16–17 (broader framing)

WO 2004/008136 A1 + EP 0 715 169 A1 + Matter + Lynnworth. Claim 16 is a parameter-collection wrapper around the same three-variable correlation. WO 2004/008136 already teaches λ + c_p → CV, density, Wobbe index, methane number by fitted polynomial correlation (explicitly: "Multivariate 3rd order polynomials … determined in a regression calculation"). Adding c_s (Lynnworth/EP0715169) to a λ+c_p correlation is a substitution of one independent variable from a known catalogue of interchangeable measurement-variable combinations — the very catalogue recited in the common owner's own family specification. Claim 17 (CV/Wobbe/Z/viscosity) falls identically to claim 5.

Combination 3 — Apparatus claims 7–15

• Claim 7 — EP 2 574 918 A1 (sensor set + evaluation) + Lynnworth (ultrasonic flow sensor) + Matter (microthermal sensor) + EP0715169 (evaluation unit 22/computer 24 correlating sound speed, λ, c_p to CV/Wobbe).
• Claims 8–9 — EP 2 574 918 claims 9–10 place both sensor blocks "directly in main gas line 1" or in a measuring line; clamp-on (non-invasive) ultrasonic meters are the ordinary commercial form of the transducer of Lynnworth's paper.
• Claim 10–12 — EP 2 574 918 claim 10 teaches a measuring line branching to main line 1 with a valve at the outlet; a differential-pressure element driving a small bypass is a routine sampling expedient (and, notably, is the arrangement the '186 itself describes in FIGS. 5–6 as requiring nothing more than "an element 5 which produces a pressure drop"). This is the weakest sub-combination — I did not retrieve an on-face reference that expressly discloses a pressure-drop element in the main line plus a calibrated bypass splitting ratio, so claims 10–11 rest on general-knowledge/mechanical-expedient reasoning (KSR) and I assign them lower confidence (§ 8).
• Claim 13 — a gas-line section housing a sensor is a purely conventional structural recitation.
• Claim 14 — modular unit vs. separate evaluation unit: EP0715169's control 22 sends the inferred CV/Wobbe "to some remote location" and to a volumetric meter "and/or computing the monetary value of the gas supplied" — i.e., a separate higher-level computing unit.
• Claim 15 — apparatus configured to perform claim 1 is obvious for the reasons in Combination 1.

6. Why a PHOSITA would have been motivated to combine

1. Same field, same problem. All references address fluctuating gas quality and correlative CV/Wobbe determination for metering, burner control, and energy billing. WO 2004/008136 opens with precisely the '186's stated motivation (market liberalization → more frequent quality swings → growing need for CV measurement).
2. A recognized, catalogued menu of correlation variable-sets. The common owner's own family spec (US 9,612,229 B2) lists the field's known combinations: "A. Dielectric constant, sonic velocity, CO₂ content; B. Sonic velocity at 2 pressures, CO₂ content; C. Thermal conductivity at 2 temperatures, sonic velocity; D. Thermal conductivity, heat capacity, dynamic viscosity…" Selecting {λ, c_p, c_s} is picking one item from combination C and one from combination D and merging them — the paradigm case of KSR's "finite number of identified, predictable solutions."
3. Predictable technical result — increased precision. Combining independent variables to reduce correlation error is the ordinary, expected consequence of redundantly measuring a system, and the '186 itself frames the advantage exactly that way ("a comparatively high level of precision … due to the correlation from the three independent variables"). Expectation of success is not speculative when the field is already doing 2-variable and 3-variable correlations (EP0715169, WO 2004/008136).
4. Free information from a sensor already in the meter. The '186's own specification concedes that the ultrasonic meter's sum-of-runtimes already contains sound velocity, "which in ultrasonic flow meters is mostly not used any further." Motivation to exploit already-sensed, previously-discarded data is a paradigm KSR improvement of a known device.
5. Substitution of hardware to eliminate an admitted drawback. The '186 admits that the Mems critical-nozzle route needs critical pressure and is "not directly suitable … at the end customer." Replacing the nozzle with a sound-velocity measurement from an ultrasonic meter is a substitution aimed at a known deficiency — and the '186 admits the nozzle route "also supplies the sound velocity in first order," i.e., the substituted element acquires the same physical quantity. That is a strong equivalency/known-substitution rationale.
6. Suitability for low-pressure networks is not a claim element, and is anyway anticipated. EP 0 715 169 explicitly contemplates domestic/industrial supply at "relatively low pressure," undercutting any "unexpectedly enabled low-pressure operation" argument as a source of nonobviousness.

7. Anticipated counterarguments and why they fail

A. "EP 2 574 918 can't be used for CV; it only classifies L/H gases." Contradicted by EP 2 574 918's granted claims 13–15, which claim determination of the gross calorific value, Wobbe index, and energy flow. The patentee's background characterization of its own earlier application is an attorney characterization, not the reference's disclosure. Moreover, a reference that identifies a precision deficiency motivates its cure; it does not teach away absent a criticism of the claimed solution (In re Fulton, 391 F.3d 1195, 1200 (Fed. Cir. 2004); MPEP § 2145). EP 2 574 918 also never disclaims combining its microthermal measurement with an acoustic sound-velocity sensor — it explicitly frames its method as upgrading any "suitable gas flow measuring technique."

B. "Empirical correlations are unpredictable (§ 103)." The '186's own specification defeats this: S_out and f_corr are "by no means predetermined, but are freely selected in such a way that the resulting correlation error becomes as small as possible," and the polynomial form "usually is successful." That is an express admission of routine optimization (In re O'Farrell, 853 F.2d 894 (Fed. Cir. 1988); MPEP § 2144.03). WO 2004/008136's multivariate 3rd-order polynomial regression shows the fitting techniques were conventional in the same field.

C. "Different physical arrangement — sample chamber vs. in-line flow-through." EP 0 715 169 uses a chamber, not a flow-through ultrasonic meter, so claim 1's "flowing … through an ultrasonic flow measuring device" is not literally anticipated by it. That is why EP 0 715 169 must be combined with Lynnworth/Matter — and the combination is plainly proper, because the substitution of an in-line transit-time ultrasonic meter for a chamber-based acoustic measurement is the kind of rearrangement expressly contemplated by KSR and permitted by In re Keller.

D. "Non-analogous art." All references are from the same field of endeavor (gas-quality/combustion measurement and gas metering) and are reasonably pertinent to the problem the inventor faced; the analogous-art defense is unavailable.

E. Common ownership note (cuts the other way — flagging for accuracy). US 9,612,229 B2 / EP 2 806 271 A1 are commonly owned by Mems AG. Under AIA § 102(b)(2)(C), commonly owned art may be disqualified as § 102(a)(2) prior art. I therefore deploy the critical-nozzle family primarily as (i) evidence of the state of the art and the content of the ordinary artisan's knowledge (its background catalogue of combinations A–F), and (ii) the applicant's own characterization of the problem — not as standalone § 102(a)(2) art. EP 0 715 169, WO 2004/008136, US 2,591,759, WO 2002/040992, and the Matter/Lynnworth NPL are all third-party art and carry no such disqualification.

F. Objective indicia. Potential evidence exists (Mems' gasQS™ fionic correlative sensor reportedly outperformed gas chromatographs and calorimeters in the 2018 GasQualityGlas project (Mems newsletter I/2019); the ~20-person company's commercial position). But (i) there is no established nexus between the commercial product and the claimed three-variable correlation rather than unclaimed features; (ii) the same field was actively being solved by others (e.g., Sensirion's later correlative thermal-sensor devices, EP 3 502 687, EP 3 153 854, which compute combustion parameters from λ and c_p-related outputs plus a third parameter) — undermining any "long-felt need / failure of others" narrative; and (iii) an additional, unclaimed advantage of a combination of known elements does not confer patentability. If this analysis is ever litigated, expect the secondary-considerations fight to turn entirely on nexus.

8. Claim-by-claim summary

9. Limitations of this analysis

• Provenance. My mappings of EP 0 715 169, WO 2004/008136, EP 2 574 918, and US 9,612,229 B2 rest on their abstracts, claims, and specification excerpts retrieved above (URLs cited). I did not obtain full texts of US 2,591,759, WO 2002/040992 A1, or US 6,786,633 B2; my treatment of those three is limited to their titles/abstracts and they are not load-bearing in any combination above.
• Prosecution history not available. All nine references appear in the "Patent Citations" list, but I cannot distinguish examiner-cited-and-overcome art from IDS-submitted art without the file wrapper. If EP 0 715 169 was substantively considered and overcome, the likely argument was the sample-chamber vs. flow-through distinction (§ 7C) — worth verifying against the USPTO PatentCenter record for App. 14/939,756 before relying on this analysis.
• No on-face reference squarely discloses the pressure-drop-main-line/bypass-with-known-splitting-ratio architecture (claims 10–12). Those claims would rest on general-knowledge/mechanical-expedient reasoning and are the most defensible of the set.
• This analysis is hypothetical; the claims issued over this art, and my conclusions do not purport to predict how a court or the PTAB would weigh secondary considerations or claim construction of "correlation" and "flow factor (φ)."