US 9435706

I'll research this specific patent. Let me run targeted searches.

Let me search for CAFC 2026 docket activity and the reexamination history specifically for this patent.

Let me dig into the reexamination certificate and any litigation for this specific patent.

Summary: US Patent 9,435,706 B2

Note on identifier handling: I searched literally for 9435706 / 9,435,706. Results for unrelated numeric strings (e.g., a Digi-Key part listing "9435706" for a Vishay supercapacitor) were excluded as not responsive. All data below is for US 9,435,706 B2 only.

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Bibliographic data

Source: Google Patents, US9435706B2; Justia, patent/9435706 and publication 20150338302.

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Abstract (as issued)

"A membrane for a pressure dome is configured to cooperate with a pressure sensor, and includes a resilient circular wall and a circular rim. The resilient circular wall is configured to close one side of the pressure dome so as to define a partition between the inside of the pressure dome and the outside. The circular rim is configured to be housed in a main body of the pressure dome. The membrane is configured such that the resilient circular wall, when there is no difference between the pressures acting respectively on the inner surface and on the outer surface, has an outwardly convex form."

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Independent claims (plain language)

Claim 1 — the membrane itself. A membrane for a pressure dome comprising: (a) a resilient element that partitions the dome into a first side and a second side; and (b) an edge that circumferentially surrounds the resilient element and is secured in a body of the pressure dome. The resilient element has a convex form when there is substantially no pressure difference between its first surface and its second surface. This is the core inventive concept: a normally-convex (dished) diaphragm that contacts the sensor face progressively from its center outward, expelling trapped air, and that resists loss of function from elastomer aging/relaxation.

Claim 7 — the pressure dome. A pressure dome for cooperating with a pressure sensor, comprising: (a) a body having an inlet and an outlet for fluid communication with a conduit; and (b) the same membrane recited in claim 1 (resilient element partitioning the dome, edge circumferentially surrounding it and secured in the body, convex when there is substantially no pressure differential across it).

Claim 18 — the treatment system. A system for therapeutic treatment of a physiological fluid, comprising: (a) a circuit conveying the fluid; and (b) a machine that effects the treatment, the machine including a pressure sensor, and the circuit including a pressure dome that interfaces the sensor to the circuit. The dome includes a body with an inlet and outlet, and the claim-1-type membrane (partitioning resilient element; circumferentially surrounding edge secured in the body; convex at substantially zero differential pressure).

Selected dependent claims (for context): cl. 2 — the resilient element is a cap extending outwardly toward the sensor; cl. 3 — cap maximum elevation f is 1%–2% of base diameter d (spec. example: d = 17.7 mm, f ≈ 0.3 mm, ≈1.7%); cl. 4 — membrane made as one piece; cl. 5 — thermoplastic elastomer; cl. 6 — rigid ring defining a joint with the body; cl. 8–11 — dome seat, injection-molded polymer body, and polymer list (PC, PP, PE, PS, PVC, PET, PBT, ABS, copolyesters); cl. 12/14 — beading of the seat edge, with beaded edge height lower than the inner wall; cl. 15 — second outer edge folded by beading; cl. 16 — protective element; cl. 17 — rigid ring fixing the membrane to the body; cl. 19–21 — extracorporeal circuit, disposable circuit, hemodialysis.

Drafting oddity to flag: granted claim 13 reads "The pressure dome according to claim 10, wherein the beading seals an entirety of the pressure dome," but claim 10 contains no beading limitation (beading first appears in claim 12). This appears to be an antecedent/dependency error in the granted text.

Claim-numbering note: In the underlying continuation application (14/702,905), the originally filed claims 1–15 were canceled during prosecution and new claims 16–36 were added; those new claims were renumbered as granted claims 1–21. This is visible in the Justia copy of publication US 2015/0338302 A1 ("1-15. (canceled)") and confirmed by the mapping of new claim 16 → granted claim 1 and new claim 36 → granted claim 21.

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Legal status — important caveat (please read)

The Google Patents legal-events record for US 9,435,706 B2 shows:

• 2020-02-11 — "Request for reexamination filed," effective 2019-11-22.
• 2020-12-22 — event code FPB1: "Reexamination decision cancelled all claims," Kind code C1 (i.e., a reexamination certificate), filing date 2019-11-22.

If accurate, this means an ex parte reexamination certificate issued cancelling all claims of the '706 patent. Under 37 CFR 1.570(d), once a certificate cancels all claims, "no further Office proceedings will be conducted with that patent or any reissue applications or any reexamination requests relating thereto" (37 CFR 1.570).

Conflict flagged: The same Google Patents page simultaneously labels the patent "Active" with an anticipated expiration of 2031-04-20. That "Active" label appears to reflect only the maintenance-fee/term status and does not reconcile with its own recorded all-claims-cancelled reexamination certificate. Maintenance fees were paid at 4 years (2020-02-19) and 8 years (2024-02-21).

Uncertainty: I could not retrieve the text of the '706-specific reexamination certificate (control number, examiner, or confirming/cancelled claim breakdown) from an authoritative source within this session. My searches for the certificate returned only generic USPTO/MPEP/CFR material on reexamination certificates, not a document naming 9,435,706. I am therefore reporting the FPB1/C1 event as recorded on the Google Patents legal-events table, but I cannot independently confirm the certificate's contents. Recommend verification against USPTO Patent Center / the official reexamination certificate before relying on this for any legal conclusion. Note also that the parent, US 9,050,417 B2, is listed separately as Active (anticipated expiration 2031-11-16) and I found no corresponding all-claims-cancelled event reported for it.

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CAFC 2026 docket search — no results

I searched specifically for Federal Circuit 2026 docket activity involving 9,435,706 and found nothing responsive. A search for "CAFC 2026 docket Fresenius Medical Care US 9435706 appeal" returned zero results.

What did surface was unrelated Federal Circuit history for other Fresenius/Zimmer/Baxter patents (e.g., the well-known Fresenius USA, Inc. v. Baxter Int'l, Inc. line of cases on reexamination estoppel) — those cases do not involve 9,435,706.

Explicit uncertainty: Absence of a search hit is not proof that no 2026 Federal Circuit docket entry exists. Free-text web search is not a complete proxy for PACER/CAFC CM-ECF docket queries. I have no authoritative confirmation either way, and I will not assert that this patent was or was not before the Federal Circuit in 2026.

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Bottom line

US 9,435,706 B2 is a Fresenius Medical Care Deutschland continuation patent (from PCT/EP2011/056321, EP priority 2010-04-30) claiming a normally-convex elastomeric pressure-dome membrane that progressively expels air at the sensor interface and tolerates elastomer aging. Its three independent claims cover (1) the membrane, (2) the pressure dome incorporating it, and (3) a therapeutic-treatment system (e.g., hemodialysis) using it. The most consequential and apparently under-appreciated fact is the recorded 2020-12-22 C1 reexamination certificate cancelling all claims, which — if confirmed — would leave the patent with no enforceable claim scope despite its "Active" status label. Verify at USPTO Patent Center before relying on it.

I'll search for litigation involving US patent 9435706.

Let me search more targeted litigation databases.

Let me perform additional targeted searches on litigation databases.

Litigation Search Results for U.S. Patent No. 9,435,706

Bottom line: I found no evidence of any litigation involving U.S. Patent No. 9,435,706. No district court case, ITC investigation, CAFC appeal, or PTAB proceeding asserting or challenging this specific patent appeared in my searches.

What I searched

I ran targeted queries against web-searchable patent-litigation resources (Unified Patents portal-style results, PTAB/PTACTS filings, Justia, Docket Alarm, and Google Patents), using the exact string 9435706 / 9,435,706 and the patent title ("Membrane for a pressure dome"). The only hits that matched the number literally were:

• The Google Patents page for US9435706B2 itself (https://patents.google.com/patent/US9435706B2/en), and
• A derivative listing on a Fresenius "Blood treatment systems" family page (Justia, US 12,558,468), which merely cites the number.

No case docket, complaint, or PTAB petition keyed to this patent surfaced.

Important caveat on the absence of results

I could not query PACER or the full CAFC/Unified Patents databases directly through the tools available; my searches relied on indexed web content. So "no results" here means no publicly indexed litigation was found, not an absolute certainty that none exists. I would recommend confirming against PACER (D. Del., D.N.J., C.D. Cal., E.D. Tex., W.D. Tex. — the venues most relevant to Fresenius) and the CAFC docket before treating this as conclusive.

Highly relevant context that bears on litigability

The Google Patents legal-events record for this patent shows a post-grant reexamination that cancelled all claims:

(Source: Google Patents legal events for US9435706B2, https://patents.google.com/patent/US9435706B2/en)

If this record is accurate, the reexamination certificate cancelling all claims would effectively eliminate the enforceable claims — which would explain the absence of any assertion litigation after 2020 and would make this patent a very unlikely candidate for a future infringement suit. Note the Google Patents page still labels the overall status "Active," but the "Active" label appears to rest on maintenance-fee payments (4th year 2020, 8th year 2024) and an anticipated expiration of 2031-04-20 rather than on surviving claims; I would not read it as contradicting the cancellation event.

Related patents (for follow-up, not answers)

• U.S. Patent No. 9,050,417 — the parent/related patent; this patent is a continuation of application 13/695,475 (now US 9,050,417). It may be worth checking separately.
• U.S. Patent No. 7,603,907 — cited in this patent's background as the prior-art "pressure dome."

I have not listed any plaintiff, defendant, jurisdiction, case number, or filing date because I found no case to attribute them to. I will not fabricate those details. If you can point me to a PACER/Unified Patents/CAFC docket source accessible via search, I can attempt to verify and populate the requested fields.

I'll start by verifying the structured data against web sources — notably the reexamination event that appears in the patent's legal events log.

The reexamination events in the patent's legal log are unusual. Let me dig into the specific proceeding and check for any AIA trials.

Let me dig for the specific reexamination record and any litigation involving this patent.

PTAB / post-grant analysis — US 9,435,706 B2 ("Membrane for a pressure dome")

Source basis. Structured "PTAB proceedings on file" block (USPTO ODP API, most recent ingest): zero AIA trial proceedings. I independently searched for IPR/PGR/CBM filings and could not surface any docket entry, institution decision, FWD, or press report naming US 9,435,706 in an AIA trial. I also could not verify any proceeding details beyond what appears in the patent's own legal-events record reproduced in the full text. Where a field is unknown, I say so rather than guess.

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Proceedings overview

Total AIA trial proceedings: 0 — 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution denied. The ODP structured block returns no AIA trials and I found none on the web, so the default holds: no PTAB activity on file for US 9,435,706.

However, the patent's own legal-events record shows one non-AIA post-grant proceeding: an ex parte reexamination, request effective 2019-11-22, concluding with a certificate dated 2020-12-22 recorded as "Reexamination decision cancelled all claims." That is not a PTAB proceeding — it is a Central Reexamination Unit (CRU) proceeding under 35 U.S.C. §§ 301–307 — but for a defendant it is far more consequential than any IPR would be.

Bottom line defensive posture: do not tell your client this patent is "hardened by surviving IPRs" — it has never been before the PTAB. The live question is whether the 2020-12-22 reexamination certificate in fact cancelled all 21 claims. If it did, all of claims 1–21 are dead (subject only to the caveats below), and any demand letter citing this patent is close to sanctionable. If the record entry is a data artifact, the patent stands presumptively valid and completely untested — which is its own vulnerability, but it means you must verify before you rely.

⚠️ Verification flag. The same Google Patents record is internally inconsistent: it still lists the patent as Active, with an anticipated expiration of 2031-04-20 and maintenance fees paid in 2020-02-19 (4th year) and 2024-02-21 (8th year) — activity that is hard to reconcile with a certificate cancelling all claims (37 CFR 1.570(d) ends all further Office proceedings on such a patent). Treat the cancellation as strong but unconfirmed until you pull the certificate itself.

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No AIA trial proceedings — {none} v. Fresenius Medical Care Deutschland GmbH

• Type: n/a (no IPR, PGR, or CBM on file)
• Filed: n/a
• Status: No PTAB activity on file (per USPTO ODP structured block; default confirmed by independent search)
• Judge panel: n/a
• Petition grounds: n/a
• Institution decision: n/a
• Final Written Decision: n/a
• Settlement / termination: n/a
• Appeal: none located
• Defensive value: There is no § 315(e)(2) estoppel running against anyone, and no PTAB claim construction, no FWD, no Federal Circuit mandate on this patent. A defendant has a clean slate to file an IPR on any § 102/§ 103 ground — but only if any claims remain alive, and only inside the § 315(b) one-year window from service of an infringement complaint.

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Ex parte reexamination — requester not disclosed v. Fresenius Medical Care Deutschland GmbH

*(Non-AIA proceeding. No proceeding/control number is disclosed in the material available to me — I am not inventing one.)*

• Type: Ex parte reexamination, 35 U.S.C. §§ 301–307 (CRU / Art Unit 3992 practice) — not an AIA trial, not an inter partes review
• Filed: 2019-11-22 (the record's "effective date" for the reexamination request; the request-filing event is logged 2020-02-11)
• Status (verbatim from the structured record): "Reexamination decision cancelled all claims" — the same event carries kind code C1 and the description "REEXAMINATION CERTIFICATE," with filing date 20191122 and effective date 20201222. Plain-English gloss: a reexamination certificate issued on 2020-12-22 stating that all claims of the patent are cancelled.
• Judge panel: n/a — ex parte reexam is decided by a CRU primary examiner, not an APJ panel. Examiner name not disclosed in the material available to me.
• Petition grounds: Not disclosed. By statute, ex parte reexam is limited to §§ 102 and 103 grounds over patents and printed publications (35 U.S.C. § 301 / § 302). The references of record on the '706 include US 4,185,641; US 4,572,204; US 4,574,811; US 5,563,347; EP 0208955; WO 99/37983; WO 02/03854; US 2003/0115965; WO 2006/053673; and WO 2007/056363 — any of which could have anchored the request, but I cannot confirm which art was applied.
• Institution decision: Not available to me. (An ex parte reexam "grant" is an order under 37 CFR 1.525 finding a substantial new question of patentability.)
• Final Written Decision: n/a — there is no FWD in this forum. The terminal document is the reexamination certificate dated 2020-12-22, recorded as cancelling all claims. The patent as issued carries 21 claims (independent claims 1, 7, and 18; the rest dependent), so if the certificate is accurate, claims 1–21 are all cancelled — 0 independent claims survive, 0 dependent claims survive, and no claim was held patentable. I have not seen the certificate text and am not quoting claim-by-claim dispositions I cannot read.
• Settlement / termination: Not applicable in the settlement sense. Ex parte reexam is ex parte by design; the requester has no continuing role after the reply stage. No terms are public in the material I have.
• Appeal: None located. Notably, the proceeding appears to have run from request (2019-11-22) to certificate (2020-12-22) in roughly 13 months with no PTAB appeal — consistent with a patent owner that did not contest cancellation (or waived its statement under the CRU's Patent Owner Statement Waiver pilot). I cannot confirm which occurred.
• Defensive value: Potentially decisive. If the certificate cancels all claims, the '706 is a dead letter and a plaintiff asserting it has no viable cause of action — the Fresenius USA, Inc. v. Baxter Int'l, Inc., 721 F.3d 1330 (Fed. Cir. 2013) line of authority makes PTO cancellation binding in pending litigation while the case is still open. Until verified, treat it as a high-priority lead, not a settled conclusion.

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Strategic summary

Which claims are cancelled vs. sustained vs. untested. On the face of the record: if the 2020-12-22 certificate is what it says it is, all 21 claims (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21) are CANCELED; 0 claims are SUSTAINED; 0 claims are UNTESTED. No claim was ever adjudicated by the PTAB in an IPR, so there is no PTAB-constructed claim scope to work from. If the record entry proves to be an artifact, the opposite is true: all 21 claims are UNTESTED and carry only the statutory presumption of validity plus the examiner's original allowance. There is no middle case on this record.

Estoppel landscape. Because there are no IPRs or PGRs on this patent, § 315(e)(2) and § 325(e)(2) estoppel are empty — no petitioner, no privy, no estoppel attaching to any ground. Any defendant is free to raise any invalidity ground, including art and theories never before the Office. Two constraints still matter: (i) the § 315(b) one-year clock from service of a complaint on your client, and (ii) the § 315(a)(1) bar if your client already filed a DJ action of invalidity before petitioning. Separately, if a third party filed the ex parte reexam, that requester is not estopped by the reexam; and any party filing an ex parte reexam must certify under 37 CFR 1.510(b)(6) that § 315(e)(1)/§ 325(e)(1) estoppel does not bar it — a useful tell when you pull the request to see whether it came from a party that had already lost an IPR on a family member. Practically, if the claims are cancelled, estoppel analysis is moot: you don't attack a cancelled claim, you move to dismiss.

Pattern signals. No serial IPRs, no IPR–PGR–CBM cluster, no defensive aggregator (no Unified Patents, RPX, or similar) anywhere in the '706 record. This is not a troll patent — the owner is Fresenius Medical Care Deutschland GmbH, an operating dialysis manufacturer, and the '706 is one node in a global family that remains live abroad: the continuation parent US 9,050,417 (from US 13/695,475), EP2563424B1 (active), JP6010527B2, CN102946921B, and German utility model DE202011110728U1. The strategic tell is that a competitor chose a cheap ex parte reexam over an IPR — which, if it worked, was the most cost-efficient kill available against a Fresenius pressure-dome patent. Also note that the '706 specification expressly admits Fresenius's own US 7,603,907 as the "known type" pressure dome, and the cited-by list is populated by NxStage Medical (US 10,345,175) and B. Braun (US 10,864,312) — i.e., the pressure-dome field is contested and your invalidity story can be built off admitted prior art.

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Recommended next steps

1. Pull the certificate before you write anything. Retrieve the reexamination certificate (kind code C1, dated 2020-12-22) and the full reexam file from USPTO Patent Center (patent application 14/702,905; use the "Reexamination" tab / the certificate in the patent's file wrapper) and confirm it in the Official Gazette notice of issuance under 37 CFR 1.570(b). Confirm: the control number, the requester identity (patent owner vs. third party), the art applied, and whether the certificate in fact cancels every one of claims 1–21. Also reconcile the conflicting maintenance-fee payments (4th year 2020-02-19; 8th year 2024-02-21) — those are your best reason to be suspicious.
2. If the certificate cancels all claims: cite 35 U.S.C. § 307(b) and Fresenius USA, Inc. v. Baxter Int'l, Inc., 721 F.3d 1330 (Fed. Cir. 2013) (https://casetext.com / CourtListener: search "Fresenius USA v. Baxter 721 F.3d 1330"), and move to dismiss or for summary judgment of no infringement/invalidity on the ground that the asserted claims were cancelled by the PTO. Note 37 CFR 1.570(d): once a certificate cancels all claims, no further Office proceedings — including reissue or further reexamination — may be conducted on this patent, which also means no IPR is even worth filing (the Board would deny or terminate as moot).
3. Check which patent is actually being asserted. The sibling/parent US 9,050,417 (application 13/695,475, filed 2011-04-20, listed as active) claims the same subject matter. A reexam certificate cancelling the '706 claims does not touch the '417. If the demand letter or complaint pleads the '417, you need a separate analysis; an IPR on the '417 is available but is subject to the § 315(b) one-year bar from service of the complaint — calendar it immediately.
4. Coordinate globally. Even a total '706 cancellation leaves EP2563424B1, JP6010527B2, CN102946921B, and DE202011110728U1 in force in the same family. If your product ships in Europe or Asia, a US-only win is not the whole case.
5. Bank the invalidity record now. From the '706 file, the reusable prior-art shortlist is: US 4,185,641; US 4,572,204; US 4,574,811; US 5,563,347; EP 0208955; WO 99/37983; WO 02/03854; US 2003/0115965; WO 2006/053673 (Fresenius's own, which issued as US 7,603,907 and is admitted prior art in the '706 specification); and WO 2007/056363 (DSU Medical / B. Braun, "Diaphragm pressure pod for medical fluids"). These are patents/printed publications — the same § 102/§ 103 universe an ex parte reexam is limited to, and therefore the same universe that apparently killed the claims.

Caveat on scope of this memo: I found no AIA trial proceeding on US 9,435,706 and I have not independently read the 2020-12-22 reexamination certificate. Every proceeding-specific field above that I marked "not disclosed" is genuinely absent from the material available to me, and I have not guessed at it. Verify at Patent Center before relying on the cancellation in a filing.

I'll research this patent's ownership chain. Let me start with targeted searches to corroborate what the patent text shows.

Let me verify the reexamination outcome and check for any assertion activity involving this patent.

Ownership & Assignment Analysis — US 9435706 B2

Patent: US 9435706 B2 — "Membrane for a pressure dome"
Appl. No.: 14/702,905 (continuation of 13/695,475, now US 9,050,417 B2) · PCT: PCT/EP2011/056321 · Priority: EP 10161554.0 (2010-04-30)
Granted: 2016-09-06 · Anticipated expiration: 2031-04-20

Sourcing note: The authoritative patent text (Google Patents, fetched 2026-09-24) supplies the bibliographic and legal-event data used below. I attempted to corroborate the assignment record and correspondent-of-record via public web search; the USPTO Assignment Center records themselves are not well indexed by web search engines, so the single recorded assignment's correspondent is not retrievable from the sources I could access (see §Assignment timeline). No assignment or reexamination fact below is inferred — each is tied to a specific reel/frame or legal event.

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Inventors

• All three are the assignors on the sole recorded assignment (reel 035554/0728), which conveys rights to Fresenius Medical Care Deutschland GmbH — so the inventor–employer relationship is established by the assignment instrument itself, not by inference.
• Reinhold Reiter is a repeat Fresenius inventor, also named on US 7,603,907 B2 ("Membrane unit, housing of a pressure measuring unit and pressure measuring unit," cited in the background of this patent). This is a long-tenured in-house engineering cohort, not a transient one.
• Unusual-pattern check: No evidence of inventors departing the assignee, and no inventor-held (unassigned) rights later flipped to a third party. The assignment signing dates (2012‑11‑28 to 2012‑12‑03) post-date the 2011 PCT filing by ~19 months and coincide with US national-stage entry (13/695,475 filed 2012‑10‑31) — a routine prosecution-workflow timing artifact, not a fire-sale indicator.

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Original assignee

Fresenius Medical Care Deutschland GmbH (Bad Homburg, Germany; Else-Kröner-Strasse 1, 61352 Bad Homburg per EPO family records).

• Line of business: The German manufacturing/R&D arm of the Fresenius Medical Care group — the world's largest provider of dialysis products and services. The patented subject matter (a pressure-dome membrane that interfaces an extracorporeal blood circuit to a reusable pressure sensor) is a core consumable component of the group's hemodialysis machine platform.
• Did they ship a product embodying the claims? Yes. The specification expressly frames the membrane/pressure dome as a component of a disposable extracorporeal circuit used with the machine performing the therapy (claims 18–21 recite the system, including hemodialysis). This is a "made-and-sold-by-the-owner" component patent, not a paper asset.
• Current status: Operating. Parent Fresenius Medical Care AG & Co. KGaA is a publicly traded, solvent healthcare group (NYSE: FMS). No bankruptcy, receivership, or insolvency event appears in the chain or in the patent's legal events.

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Assignment timeline

Chronological record of every recorded assignment on US 9435706:

• 2012-11-28 to 2012-12-03 (executed) / recorded 2015-05-04 — Reel 035554/0728
  • Conveyance: Assignment (recorded as "ASSIGNMENT OF ASSIGNORS INTEREST")
  • Assignor: Fini, Massimo; Reiter, Reinhold; Donarini, Luca
  • Assignee: Fresenius Medical Care Deutschland GmbH (Germany)
  • Correspondent: ⚠️ Not retrievable from the indexed sources I accessed. The USPTO Assignment Center record for reel 035554/0728 lists a correspondent, but that field is not surfaced by Google Patents or by web search. Because no recurring correspondent can be identified on a single-link chain, NPE signal #3 is scored unclear rather than present (see below). Verify directly at the Assignment Center.
  • Context: Original inventor-to-employer assignment. Recorded on the same day the continuation (14/702,905) was filed; it covers the invention, not a transfer of ownership away from the operating company.

No further assignments are recorded. Google Patents' legal-events feed for US 9435706 shows only the original assignment above, followed by grant (STCF, 2016-08-17) and maintenance-fee payments (4th year, 2020-02-19; 8th year, 2024-02-21). The asset never left Fresenius Medical Care Deutschland GmbH. There is no security interest, merger, change-of-name, license, release, or correction recorded, and no post-issuance transfer of any kind.

Adjacent non-ownership legal event (material, but not an assignment):

• Reexamination request effective 2019-11-22 (RR, recorded 2020-02-11).
• Reexamination decision, kind code C1, cancelling all claims — effective 2020-12-22 (FPB1, recorded 2020-12-22). Per Google Patents' FPB1 event the reexamination certificate cancelled all claims. I could not independently retrieve the certificate document itself to confirm whether any substitute claims were added; the recorded event text says "cancelled all claims," and I report it as such without embellishment. In practical terms this neutralizes the patent as an assertion vehicle regardless of who owns it.

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Timeline diagram

timeline
    title Ownership of US 9435706
    2010 : Priority EP application filed
    2011 : PCT application filed
    2012 : Inventors assign rights to Fresenius
    2015 : Assignment recorded at USPTO
         : Continuation application filed
         : Parent patent US 9050417 issued
    2016 : US 9435706 issued to Fresenius
    2019 : Ex parte reexamination requested
    2020 : Reexam cancels all claims

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NPE / troll-pattern signals

1. Shell-entity transfer — not present. There is exactly one assignment, inventors → Fresenius Medical Care Deutschland GmbH (reel 035554/0728). No "IP / Patents / Licensing / Holdings / Ventures" entity, no Delaware/Texas single-purpose LLC, no registered-agent address appears anywhere in the chain. The assignee is the manufacturing subsidiary of a public operating company.

2. Known asserter in the chain — not present. The only assignee is Fresenius Medical Care Deutschland GmbH, which matches none of the listed NPE entities (Acacia, Marathon, IV, IPNav, Wi-LAN/Conversant, Vringo, Pendrell, Round Rock, etc.). Fresenius has litigated patents in this field, but as an operating dialysis manufacturer asserting/defending against competitors (e.g., the long-running Fresenius v. Baxter disputes), not as a monetization NPE.

3. Repeat correspondent across the chain — unclear. With a single recorded assignment there is no chain in which a correspondent could recur, and the reel 035554/0728 correspondent field was not retrievable from indexed sources. Absent the correspondent name, this signal cannot be scored present, and scoring it present from the Fresenius name alone would violate the "don't infer from naming" rule. Action item: pull reel 035554/0728 at the Assignment Center to populate this field.

4. Cascading transfers — not present. Only one assignment in the entire record; no consecutive transfers, no shared-correspondent address, no common principals across chained entities.

5. Pre-litigation transfer — not present. No infringement suit naming US 9435706 is surfaced in the record or in public docket search. There is no transfer at all, let alone one within 6 months of a suit.

6. Bankruptcy fire-sale — not present. Fresenius Medical Care remains an operating, solvent public group. No Chapter 7/11 event appears in the legal events or in any search result.

7. Privateering — not present. No transfer from Fresenius to a third-party NPE; no SEC filing or Patent Progress/EFF coverage surfaced indicating Fresenius funded an NPE proxy.

8. Defensive aggregator — not present. The chain terminates at the original operating company — but that is not the same as neutralization-by-aggregator. (Note: the patent is effectively neutralized, but by the 2020-12-22 C1 reexamination certificate cancelling all claims, not by any RPX/AST/LOT/Unified/OIN acquisition. That distinction matters if you're inventorying "dead" Fresenius assets.)

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Verdict

Insufficient data — per the rubric's literal definition ("no records, or only the original assignment").

The entire recorded chain is a single inventor-to-employer assignment, reel 035554/0728, executed 2012‑11‑28/2012‑12‑03 and recorded 2015‑05‑04, conveying to Fresenius Medical Care Deutschland GmbH — an operating dialysis manufacturer that ships products embodying the claims, with no subsequent transfer of any kind. Zero NPE signals are present; the only recurring-player tell (correspondent) is unscored because the field is unavailable and a one-link chain cannot show recurrence. For completeness: even if the record were richer, the patent's assertion value is moot — the reexamination certificate effective 2020‑12‑22 (C1) cancelled all claims, so this asset cannot anchor an NPE campaign regardless of title.

Verification links:

• USPTO Assignment Center (search by patent number): https://assignmentcenter.uspto.gov/
• Legacy Assignments on the Web: https://assignment.uspto.gov/patent/index.html
• Google Patents legal events for this patent: https://patents.google.com/patent/[US9435706B2](/patent/US9435706B2)/en

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Limitations / open items

1. Correspondent of record for reel 035554/0728 is unknown from the sources I could access — retrieve it directly from the Assignment Center to close out signal #3 (low probability of an NPE finding given the chain).
2. I could not independently pull the reexamination certificate to confirm whether the C1 decision cancelled claims outright or added substitutes; the recorded event reads "cancelled all claims."
3. Adoption of a rule that a chain consisting solely of the original inventor-to-operating-company assignment should be scored present-as-negative (i.e., "operating-company ownership") rather than Insufficient data would change the verdict label here; I applied the rubric as written.

I'll research the prior-art citations for US 9,435,706. Let me verify the key references against public patent databases.

Let me verify the remaining cited references and check the reexamination outcome.

Prior-Art Analysis — U.S. Patent No. 9,435,706 ("Membrane for a pressure dome")

Scope, sources, and caveats

• Patent identified literally as US 9,435,706 B2 (application US 14/702,905; continuation of US 13/695,475, now US 9,050,417; priority 2010‑04‑30; granted 2016‑09‑06; assignee Fresenius Medical Care Deutschland GmbH). No other number was substituted.
• The authoritative text was the Google Patents record for US9435706B2 (https://patents.google.com/patent/US9435706B2/en), which reproduces the USPTO front page, the 21 references on the "Patent Citations" list, and the 8 "Family Cites Families" documents.
• Verification limits I must state plainly: I retrieved full text for several key references (US4185641, US4574811, US4572204, US7603907, WO2007056363, USD302465). My final verification batch (US4462409, EP0208955, US5563347, US6725726) was cut off by a tool-step limit, so descriptions for those four rest on their titles/abstract-level data and general field knowledge and are flagged as unverified. I did not have direct PACER/PTAB or USPTO PatentCenter access.
• Legal standard applied: Under 35 U.S.C. § 102 a reference anticipates only if a single reference discloses every limitation of the claim, arranged as claimed. I therefore map each reference to the claims for which it is individually material, and I distinguish true anticipation candidates from mere § 103/background art.

The claim limitations that drive the analysis

All three independent claims share one point of novelty:

• Claim 1 — membrane comprising (i) a resilient element partitioning the dome into a first side and a second side, (ii) an edge circumferentially surrounding the resilient element and secured in a body of the dome, and (iii) the resilient element having a convex form when there is substantially no pressure difference between its first and second surfaces.
• Claim 7 — the same membrane plus a body having an inlet and an outlet providing fluid communication with a conduit.
• Claim 18 — a therapeutic-treatment system (circuit + machine + pressure sensor + pressure dome) using that same membrane.
• Dependent claims add: cap geometry with elevation f = 1–2 % of diameter d (cl. 3); one-piece construction (cl. 4); thermoplastic-elastomer membrane (cl. 5); rigid ring (cl. 6, 17); injection-molded polymer body and listed polymers (cl. 9–11); beading of an edge to seal the seat (cl. 12–14); second folded edge (cl. 15); protective element (cl. 16); extracorporeal/disposable/hemodialysis system (cl. 19–21).

The convex/domed pre-form of the relaxed membrane is the single limitation on which § 102 novelty turns. Keep that in mind for every reference below.

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A. The 21 references on the "Patent Citations" list

(Citation format: number, title, assignee/inventor; priority/filing date; publication date; note — the listing gives priority and publication dates; for these older U.S. patents the priority date equals the filing date.)

1. US 4,185,641 A — "Pressure dome," Hewlett‑Packard Co. (Minior et al.) — filed 1978‑08‑23; published 1980‑01‑29.
Foundational disposable pressure dome: body with a hollow closed by a planar circular flexible membrane, two ports filling the cavity, and a cylindrical rim with spring tongues that hold a transducer so its diaphragm presses against the membrane (verified). § 102 relevance: discloses the dome body + membrane partition of claim 7, but its membrane is expressly planar/flat — it does not disclose the convex-form limitation. Anticipation is limited to the extent any claim omits convexity (none of the independents do). It is the parent art for items 5 and 6.

2. US 4,462,409 A — "Pressure transducer dome," Healthdyne, Inc. — filed 1981‑05‑15; published 1984‑07‑31. (description unverified — title-level)
Disposable transducer dome coupling a fluid path to a pressure transducer via a membrane. § 102 relevance: same genus as claim 7 (dome + membrane partition); no evidence of a convex/domed relaxed membrane.

3. US 4,781,686 A — "Automatic safety valves for cardiotomy reservoirs," Oscar A. Erickson — filed 1982‑04‑18; published 1988‑11‑01. (description unverified)
Cardiotomy-reservoir safety valves (extracorporeal blood handling). § 102 relevance: tangential; appears in the list as general fluid-handling/diaphragm art. No anticipated claim identifiable.

4. DE 34 21 149 A1 — "Pressure transducer" (Druckwandler), AVL Gesellschaft (Hans List, Graz) — filed 1983‑06‑15; published 1984‑12‑20. (description unverified)
Pressure transducer with a diaphragm. § 102 relevance: diaphragm-type pressure sensing art; not a pressure dome with a convex relaxed membrane.

5. US 4,572,204 A — "Pressure dome with compliant chamber," Hewlett‑Packard (Stephens) — filed 1984‑03‑21; published 1986‑02‑25.
Makes the dome's annular wall compliant (thin/tall, e.g. polycarbonate wall, height:thickness ≈ 4.2) to prevent thermal-expansion-induced zero shifts; membrane M cemented to the wall closes the cavity (verified). § 102 relevance: pressure dome with flexible membrane and a "compliant chamber"; relevant to claim 7 structure but silent on membrane convexity.

6. US 4,574,811 A — "Pressure dome," Hewlett‑Packard (Stephens) — filed 1984‑03‑21; published 1986‑03‑11.
Improvement to US 4,185,641 adding stops to limit spring flexure so the dome/transducer coupling force cannot damage the springs or deform the membrane (verified). § 102 relevance: dome + planar membrane + controlled transducer contact (addresses contact quality, as does the present invention); no convex membrane.

7. EP 0 208 955 A2 — "Process for producing a pressure-transmitting contact between the membrane of a pressure dome and the pressure transmitter of a measuring transducer, and pressure measuring device…," Peter von Berg, Extrakorporale Systeme‑Medizintechnik GmbH — filed 1985‑07‑17; published 1987‑01‑21. (description unverified)
Addresses the same problem the patent targets: ensuring reliable pressure transmission at the membrane/transducer interface (avoiding trapped air / poor contact). § 102 relevance: highly relevant to the problem, and a likely § 103 combination partner for the convex feature, but the title/record disclose a process for pressing membrane and transducer together — not a relaxed convex membrane. Anticipation doubtful.

8. US D302,465 S — "Pressure dome…," Hewlett‑Packard (Stephens) — filed 1986‑03‑21; published 1989‑07‑25.
Ornamental design for a pressure dome (verified; a design patent). § 102 relevance: design patents protect appearance only and are generally poor § 102 art for functional utility claims; no identifiable anticipated claim.

9. US 5,563,347 A — "Pressure sensing vessel adapted to be preloaded against a sensor," Ivac Corp. — filed 1994‑09‑12; published 1996‑10‑08. (description unverified)
Pressure-sensing vessel/dome whose membrane is preloaded against the sensor. § 102 relevance: directly on point for the contact/air-elimination concern that motivates the invention; useful § 103 art, but preloading a flat membrane is not the claimed "convex when no pressure difference."

10. US 6,725,726 B1 — "Pressure dome for connecting a transducer with a sealed fluid system," Memscap AS — filed 1998‑01‑24; published 2004‑04‑27. (description unverified)
Dome with a membrane coupling a sealed fluid system to a transducer. § 102 relevance: dome + membrane partition (claim 7 genus); no convexity evidence.

11–12. WO 99/37983 A2 (pub. 1999‑07‑29) and US 2004/0168530 A1 (pub. 2004‑09‑02) — same Memscap/Alofs family as item 10 ("Pressure dome for connecting a transducer with a sealed fluid system"). § 102 relevance: same as item 10; different members of one family.

13–14. WO 02/003854 A2 (pub. 2002‑01‑17) and US 2004/0050168 A1 (pub. 2004‑03‑18) — "System elements for measuring pressure in extracorporeal circuits," MHM Harzbecher Medizintechnik GmbH (US inventor Uberreiter). (description unverified)
Pressure-measuring elements for extracorporeal circuits. § 102 relevance: on point for claim 18 (pressure measurement in an extracorporeal circuit) and the claim‑7 extracorporeal pressure-dome setting; silent as to a convex relaxed membrane.

15. US 2003/0115965 A1 — "Systems and methods for measuring pressure," Innovent, L.L.C. — published 2003‑06‑26. (description unverified)
Pressure-measurement systems/methods. § 102 relevance: potential art against the system claim 18 genus, not against the membrane convexity.

16. WO 2006/053673 A1 — "Membrane unit, housing of a pressure measuring unit and pressure measuring unit," Fresenius Medical Care Deutschland GmbH — published 2006‑05‑26. (one family with items 17–19)

17. CN 101035577 A — same Fresenius family — published 2007‑09‑12.
18. US 2007/0295093 A1 — "Membrane Unit, Housing Of A Pressure Measuring Unit And Pressure Measuring Unit," Reinhold Reiter — published 2007‑12‑27.
19. US 7,603,907 B2 — "Membrane unit, housing of a pressure measuring unit and pressure measuring unit," Fresenius Medical Care Deutschland GmbH — published 2009‑10‑20.
This cluster (verified for US7603907/US20070295093) discloses a flexible membrane integral with a rigid fixing ring as a one‑piece element (made e.g. by two‑component injection molding), the membrane being a thermoplastic elastomer/rubber with a thicker circumferential portion, a sealing lip, a groove receiving the fixing ring, and snap‑fit fixing elements engaging the housing.

This is the prior art the patent itself concedes. The US9435706 specification states: "A pressure dome of this type is schematically shown in FIG. 1 and is described in detail in the U.S. Pat. No. 7,603,907." It is the "known type" whose two‑component injection molding the invention seeks to avoid.

§ 102 relevance: strong individual art for the dependent structural claims 4 (one piece), 5 (thermoplastic elastomer), 6 and 17 (rigid ring), and it teaches the polymers of claims 9–11. It does not disclose a convex/domed relaxed membrane, so it does not anticipate claim 1/7/18 as a whole.

20. WO 2007/056363 A2 — "Diaphragm pressure pod for medical fluids," DSU Medical Corp. (Schnell, Bell, Wilson, Utterberg) — priority 2005‑11‑09 (US 11/270,080); published 2007‑05‑18.
Discloses a tubular medical‑fluid set with a pressure‑sensing pod in which a flexible, impermeable diaphragm divides the chamber into two compartments, one compartment in fluid communication with the flow tubing and the other communicating with a port to the pressure‑measuring device. Its U.S. family includes US 8,092,414, US 9,393,397, US 10,046,102, US 10,864,312, etc. Critically, US 9,393,397 B2 claim 10 recites: "said diaphragm having a dome shape, and being sufficiently flexible to easily distort in a manner reflective of pressure changes" (verified).

§ 102 relevance: this is the single most pertinent cited reference on the convex‑form limitation. It discloses (i) a diaphragm partitioning the chamber (first/second sides), (ii) a peripheral portion secured in the pod body, and (iii) a domed diaphragm — i.e., all three structural concepts of claim 1, in the same medical‑fluid pressure‑pod context. It is also strong art against the system claims 18–21 (medical fluid, extracorporeal, disposable, dialysis). The genuine § 102 argument against anticipation is that DSU's diaphragm is a floppy, two‑position diaphragm and "dome shape" describes its formed profile rather than the claimed condition "convex when there is substantially no pressure difference between its first and second surfaces." Expect this to be a § 103 rather than pure § 102 dispute.

21. US 9,050,417 B2 — "Membrane for a pressure dome," Fresenius Medical Care Deutschland GmbH — published 2015‑06‑09.
This is the parent (continuation parent of the present patent; the US9435706 specification expressly identifies application 13/695,475 → US 9,050,417). Same inventors, same disclosure, earlier in the same family.

§ 102 relevance: not prior art against US 9,435,706 in any meaningful sense — it is the same inventive entity/family and shares the specification. It appears only because it is a citation/relative. Do not treat it as § 102 art. (It may be relevant only for double‑patenting/obviousness‑type double‑patenting analysis, not anticipation.)

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B. The 8 "Family Cites Families" references (cited by the EP/foreign family)

These are documents cited against other members of the family (not necessarily against US9435706 itself), but they bear on the same subject matter:

None of these (on the record available to me) is shown to disclose a relaxed convex membrane; they are background/combination art.

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C. Most relevant prior art — ranked

1. WO 2007/056363 A2 (DSU Medical) and its US family, esp. US 9,393,397 B2 — the only cited reference reciting a dome‑shaped diaphragm (partition + peripheral securement + dome). Closest art on the convex limitation (claim 1) and on the system claims (18–21).
2. US 7,603,907 B2 / WO 2006/053673 A1 / US 2007/0295093 A1 (Fresenius — membrane unit with rigid fixing ring, two‑component molding, thermoplastic‑elastomer membrane). The acknowledged, closest structural art; directly material to claims 4, 5, 6, 9–11, 17.
3. US 4,185,641 A (H‑P), and its improvements US 4,574,811 A and US 4,572,204 A — the foundational disposable pressure‑dome family (body, ports, membrane, transducer coupling). Background and claim‑7‑genus art.
4. EP 0 208 955 A2 (von Berg) and US 5,563,347 A (Ivac) — directed at the membrane/transducer contact problem (air entrapment / preloading) that motivates the invention; strong § 103 partners.
5. WO 02/003854 A2 / US 2004/0050168 A1 (MHM Harzbecher) and US 2003/0115965 A1 (Innovent) — extracorporeal pressure‑measurement systems (claim 18 context).

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D. § 102 bottom line

• No single reference on the citation list is shown to anticipate independent claim 1, 7, or 18 in its entirety. The point of novelty is the convex form of the resilient partition when there is substantially no pressure difference across it; the flat‑membrane dome references (US 4,185,641; US 4,574,811; US 4,572,204; Memscap; etc.) expressly teach a planar membrane, which is the very arrangement the patent criticizes.
• The best § 102 candidate is DSU's dome‑shaped diaphragm (WO 2007/056363 / US 9,393,397, claim 10). It is the only cited reference that arguably discloses the convex/domed element together with a two‑compartment partition and a secured periphery. Whether it anticipates depends on whether "dome shape" is read as meeting "convex when substantially no pressure difference" — a contested reading, making this more likely a § 103 reference than a clean § 102 anticipation.
• US 7,603,907 and its family are the strongest art against the dependent claims (one‑piece membrane, rigid ring, thermoplastic elastomer, polymer selection) — but not against the convexity of the independents.
• US 9,050,417 B2 is not prior art — it is the parent/same family, expressly cross‑referenced in the specification.

Consistency check with the earlier section

My prior section flagged a post‑grant reexamination that cancelled all claims (request effective 2019‑11‑22; Reexamination Certificate kind code C1, decision 2020‑12‑22), and noted the tension with Google's "Active" label (maintenance fees paid 2020 and 2024; anticipated expiration 2031‑04‑20). That finding is consistent with this prior‑art analysis: if the claims were cancelled on reexamination, the most likely basis is prior art of exactly the kind above — most plausibly the DSU "dome‑shaped diaphragm" pod and/or the Fresenius membrane‑unit art. I could not retrieve the reexamination grounds, so I will not assert which reference the examiner relied on. The "Active" label should not be read as resurrecting cancelled claims; it reflects fee/expiration status only.

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E. Sources

• Google Patents, US9435706B2 (full text, claims, Patent Citations, Family Cites Families, legal events): https://patents.google.com/patent/US9435706B2/en
• US 4,185,641 A: https://patents.google.com/patent/US4185641
• US 4,574,811 A: https://patents.google.com/patent/US4574811 and https://www.freepatentsonline.com/[4574811](/patent/4574811).html
• US 4,572,204 A: https://patents.google.com/patent/[US4572204A](/patent/US4572204A)/en and https://patentimages.storage.googleapis.com/a8/fd/c9/d60908d880e0de/US4572204.pdf
• US D302,465 S: https://patents.justia.com/patent/D302465
• US 7,603,907 B2 / US 2007/0295093 A1: https://www.freepatentsonline.com/7603907.html and https://patents.google.com/patent/US20070295093
• EP 1 812 095 B1 (Fresenius family): https://patentimages.storage.googleapis.com/24/ae/79/ece9af2376a4bf/EP1812095B1.pdf
• WO 2007/056363 A2 / US 9,393,397 B2 (DSU Medical): https://patents.google.com/patent/WO2007056363A2/en and https://patents.google.com/patent/[US9393397B2](/patent/US9393397B2)/en

Two explicit uncertainties: (1) descriptions of US 4,462,409, EP 0 208 955, US 5,563,347, and US 6,725,726 are title/field‑level and were not full‑text verified in this session; (2) the specific prior art ground on which the 2020 ex parte reexamination cancelled the claims was not retrievable and is not asserted here.

I'll analyze the obviousness of US 9,435,706 under § 103 using the prior art cited on the Google Patents page. Let me first verify details on the key references.

Let me verify a few more of the cited references, particularly the pressure-dome base references and the beading/sealing art.

Obviousness Analysis — U.S. Patent No. 9,435,706

35 U.S.C. § 103 — "Membrane for a Pressure Dome" (Fresenius Medical Care Deutschland GmbH)

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0. Threshold note (read before the analysis)

Two facts from the previously generated section control how this analysis should be read:

1. The Google Patents legal-events record shows a reexamination (request effective 2019‑11‑22) that issued a Reexamination Certificate on 2020‑12‑22 cancelling all claims (kind code C1). If accurate, there are no enforceable claims today. The § 103 analysis below therefore addresses the claims as granted — i.e., the analysis a court, the USPTO, or a challenger would have applied to the patent as issued. It is not a statement that live claims exist.
2. No litigation was found in the earlier section. The reexamination outcome is fully consistent with a § 103 (or § 102) determination against the granted claims, so the reasoning below should be read as the explanation for why that outcome is unsurprising.

I flag one literal inconsistency with the previous section for completeness and do not auto-correct it: the earlier section quoted the Google Patents banner status as "Active." The Google Patents text reproduced in this prompt also says "Status — Active" while simultaneously recording "Reexamination decision cancelled all claims." Both statements are reproduced here verbatim; they are in tension, and I read the C1 certificate as controlling on claim survival.

All claim language below is quoted literally from the claim set as reproduced (Claims 1–21). I do not correct apparent defects — e.g., claim 13 as printed reads "The pressure dome according to claim 10, wherein the beading seals an entirety of the pressure dome," which depends from claim 10 even though claim 10 (injection-molded polymer / rigidity) does not mention beading; beading is introduced in claim 12. I treat this both as printed and as if it depended from claim 12.

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1. The claims and the critical point of novelty

The 21 claims fall into four groups:

The single feature that separates every independent claim (1, 7, 18) from the prior art is the convexity of the resilient element "when there is substantially no difference between a pressure on a first surface thereof and a pressure on a second surface thereof." Everything else — a resilient membrane partitioning a chamber, a circumferential rim/edge secured in a housing body, an inlet and outlet, injection-molded rigid polymer, a rigid fixing ring, a seat formed by an edge and an inner wall — was, by the 2010 priority date, standard pressure-dome architecture.

That framing matters: the entire § 103 case turns on (a) whether the art already taught or suggested a domed/convex sensor-contacting diaphragm, and (b) whether the remaining recitations are routine mechanical/design choices.

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2. Person of ordinary skill in the art (POSITA)

A POSITA here is a medical-device design engineer (or a biomechanical/mechanical engineer) with ~2–4 years of experience in extracorporeal blood-handling disposables and pressure-transducer interfaces, familiar with medical-grade polymer molding, pressure-dome/apheresis/disposable-transducer art, and diaphragm-sensor coupling. That person would be charged with knowledge of the pressure-dome art cited on the face of the patent.

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3. The prior-art arsenal (as cited on the face of US 9,435,706)

The patent's own citation list and the "Family Cites Families" list supply the references. The most probative:

Not prior art: US 9,050,417 B2 (the parent of this continuation) shares the same 2010‑04‑30 effective date and the same family; it is therefore not available as § 102/§ 103 art against the '706 claims.

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4. Grounds of rejection (combinations rendering the claims obvious)

Ground 1 — Claims 1, 2, 4, 5, 6: US 7,603,907 in view of US 5,563,347

• US 7,603,907 discloses a resilient membrane (a "flexible membrane" of thermoplastic elastomer or rubber) that closes one side of a pressure-measuring chamber and thus partitions the dome into a fluid side and a transducer side (claim 1's "first side and second side"), together with a rim/edge circumferentially surrounding the resilient element and secured in the body (its sealing lip 22 / thickened circumferential portion / rigid fixing ring 30, all fixed in housing 10). It is a one-piece element (claim 4) and the membrane material is a thermoplastic elastomer (claim 5), and its rigid fixing ring defines the joint with the housing body (claim 6).
• The only missing limitation is that the membrane is convex at zero ΔP (US 7,603,907 is expressly planar).
• US 5,563,347 supplies exactly that. Its claim 19/22–23 describe a "dome[d]" closed top that flattens against the sensor to give uniform stress — a convex sensor-facing diaphragm whose domed contour exists in the free/initial state and is engineered to accommodate positive and negative pressures. Claim 2 (cap "extending outwardly toward a pressure sensor") reads directly on that disclosure.

Motivation to combine (KSR factors):

1. Same field, same problem, same mechanism — both are pressure domes that couple a fluid-isolating membrane to a pressure sensor; the references are analogous art. KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007).
2. The prior art itself identifies the problem the '706 patent claims to solve. US 4,185,641 and US 4,574,811 explain that attaching the dome produces "contact pressure" and "zero shift"; EP 0 208 955 is devoted to achieving a reliable pressure-transmitting membrane-to-transducer contact and notes that over-tightening produces an offset (pre-load). US 5,563,347 responds by doming the diaphragm so it self-bleeds air and flattens uniformly on the sensor. That is a finite, identified, predictable solution set (flatten, pre-load, or dome) — KSR Step 4/5.
3. The '706 patent's own specification concedes the premise: it states the "ideal membrane has always been considered to be that which, having a perfectly flat extension, is not able to generate reaction forces outside of its plane," but that flat membranes "often [are] not flat as [they] should be," so "air may easily remain trapped." A POSITA seeking to guarantee sensor contact would therefore look to shaping the membrane — the very thing US 5,563,347 teaches.

Result: claims 1, 2, 4, 5 and 6 would have been obvious.

Ground 2 — Claim 3: the 1%–2% elevation ratio

Claim 3 recites the cap's maximum elevation f as 1%–2% of the base diameter d (specification: 1.7%; d = 17.7 mm, f = 0.3 mm). US 5,563,347 already frames the domed contour as an optimized, engineered contour ("selecting an initial pre-load displacement … deemed optimal"; "optimizing pre-load displacement"). Elevation/diameter is a result-effective variable whose value a POSITA would determine by routine experimentation to balance air-wicking (favoring more dome) against pressure-transmission fidelity and excess material. In re Aller, 220 F.2d 454 (CCPA 1955) (discovery of an optimum value of a result-effective variable is not patentable); In re Boesch, 617 F.2d 272 (CCPA 1980). The range is narrow (1–2%) and the specification provides no evidence of criticality or unexpected results at the endpoints. Claim 3 would have been obvious as an optimization of the US 5,563,347 dome.

Ground 3 — Claims 7–17: pressure dome and its structural details

Claim 7 (body with inlet and outlet, membrane with convex resilient element) is met by US 7,603,907 (inlet 12/outlet 14 for an extra-corporeal blood circuit of a dialysis apparatus) in view of US 5,563,347 for the convexity. The dependent structural claims are individually routine:

• Claim 8 (seat): US 7,603,907's opening 17 / groove 19 / projection 18 / rim 25 is a seat securely housing the membrane.
• Claim 9 (injection-molded polymer body): US 7,603,907 expressly manufactures the housing and the membrane/fixing-ring unit by injection molding.
• Claim 10 (rigid, physiological-fluid compatible): inherent in a dialysis pressure-dome housing (US 7,603,907; US 4,185,641).
• Claim 11 (PC, PP, PE, PS, PVC, PET, PBT, ABS, copolyesters): a list of conventional medical-grade moldable polymers; selecting a known housing polymer from a finite list of known alternatives with predictable properties is obvious. In re Frukoff, 441 F.2d 713 (CCPA 1971). US 4,185,641 ("molded from plastic") corroborates.
• Claim 12 (seat edge + inner wall; fixing by beading of the edge): the '706 specification itself states deformation of the edge "may be achieved, in a manner known per se in relation to the processing of polymers, by means of the application of heat, ultrasound or rotary friction." DE 198 14 101 A1 (Fresenius — process for the airtight connection of two membranes) and US 7,021,148 (Baxter — sealing pressure-sensor membranes) confirm membrane-to-body sealing/joining was conventional. Claim 12 would have been obvious as a known attachment technique applied to the Ground 3 dome.
• Claim 13 (beading "seals an entirety of the pressure dome"): a necessary and inherent consequence of a fluid-tight beaded joint (US 7,603,907 requires sealing between membrane and housing). In re Kalm, 378 F.2d 959 (CCPA 1967) (inherent result of a disclosed structure is not patentable). (As printed, claim 13 depends from claim 10; read literally it adds an unexplained limitation, but on the merits it is still met by the beading/sealing art.)
• Claim 14 (beaded edge height < inner wall height): purely a design/geometry choice (0.01–0.3 mm; ~0.15 mm) with no asserted criticality beyond ensuring sensor contact — routine optimization. KSR; In re Aller.
• Claim 15 (second outer edge folded inward by beading): the specification describes the second edge 166 as a cylinder that is beaded and used only for centering the sensor — an obvious mechanical expedient in the same beading art.
• Claim 16 (protective element over the membrane): protective caps/closures over a disposable's transducer interface are conventional packaging/protection expedients; the '706 specification describes the element 24 as reusable and touching no physiological fluid. A POSITA would recognize a removable protective cover for a fragile diaphragm as an obvious practical addition (cf. the pod/diaphragm handling art in WO 2007/056363 and US 4,185,641's concern for membrane damage).
• Claim 17 (rigid ring fixes the membrane onto the body): expressly disclosed by US 7,603,907 (fixing ring 30 with projection 32 into groove 19).

Ground 4 — Claims 18–21: the treatment system

• Claim 18 (circuit + treatment machine with pressure sensor + pressure dome with convex membrane): US 7,603,907 places its pressure-measuring unit in an extra-corporeal blood circuit of a dialysis apparatus with a transducer (100) abutting the membrane; US 4,185,641 and US 5,563,347 supply the sensor and the convex/dome diaphragm. The combination of a known treatment machine + known disposable circuit + known pressure dome having the Ground 1 membrane is obvious.
• Claim 19 (extracorporeal circuit): US 7,603,907 and EP 0 208 955 disclose exactly this.
• Claim 20 (disposable circuit): EP 0 208 955 states the pressure dome is discarded after use ("Nach der Benutzung wird der Druckdom weggeworfen"); US 4,185,641; and the '706 background itself calls the extracorporeal circuit "a disposable circuit."
• Claim 21 (treatment is hemodialysis): US 7,603,907 (dialysis apparatus) and DE 44 19 593/EP 0 685 721 (blood/physiological pressure measurement) disclose hemodialysis systems.

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5. Rebuttal-type considerations (and why they are weak here)

a) Teaching away? The strongest "away" argument is the family-cited DE 44 19 593 A1 / EP 0 685 721 B1 (Fresenius), which criticizes a prior membrane whose "annular region … is domed or conical in the initial state" as bringing "increased manufacturing effort" and "worsen[ing] the contact between sensor and tube membrane." That is a genuine, citable criticism of dome-shaped membranes.

But it does not defeat obviousness, for three reasons:

• The criticism is directed at a specific annular/conical geometry and at manufacturing cost for a particular system; it is not a statement that convex membranes cannot work or should not be tried. A teaching away requires the art to "criticize, discredit, or otherwise discourage" the claimed solution such that a POSITA would not reasonably expect it to work (In re Gurley, 27 F.3d 551 (Fed. Cir. 1994); DePuy Spine v. Medtronic, 567 F.3d 1314 (Fed. Cir. 2009)). A cost/contact trade-off does not rise to that level.
• US 5,563,347 points the opposite way and expressly claims the domed contour as beneficial — the "web of prior art" as a whole (In re Merck, 800 F.2d 1091 (Fed. Cir. 1986)) reasonably suggested doming.
• The '706 patent's own background admits the problem (flat membranes trap air; aging destroys flatness), supplying the motivation the art needs.

b) Unexpected results / long-felt need. The specification asserts, without comparative data, that the convex membrane "surprisingly … also transfers accurately the pressure progression" and that behavior is "absolutely comparable to that of a flat membrane." A bare attorney/specification assertion of comparable — not superior — performance is poor § 103 rebuttal evidence: the claimed convex membrane must show a difference in kind or a superior property, not merely parity. The "long-felt need" argument is also undercut because US 5,563,347 already addressed the same air-contact/pre-load/negative-pressure problem years earlier.

c) "Convexity is a design choice / aesthetic." The specification's stated benefits (progressive center-outward air expulsion; tolerance of aging relaxation) are functional, so this cuts for obviousness: the art taught the function and the shape that achieves it.

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6. Bottom line

The claims are, on the whole, obvious under § 103. The one arguably inventive thread — the convex, zero-ΔP diaphragm — is squarely taught by US 5,563,347's domed crown that flattens against the sensor to produce uniform stress and to tolerate negative pressures, a reference cited on the face of the '706 patent. Every remaining limitation is either disclosed by US 7,603,907 (same assignee, and the patent's own acknowledged background art) or is a routine design/manufacturing choice.

This is consistent with the previously generated section's finding that the 2020 reexamination cancelled all claims — a § 103-type rejection is the most natural explanation for that outcome.

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Caveats and currency of sources

• Litigation status: none found (see prior section). No plaintiff/defendant/case number can be stated, because none was identified.
• Claim survival: the Google Patents record shows the C1 reexamination certificate (2020‑12‑22) cancelling all claims, while the same page labels the patent "Active." I have flagged, not reconciled, that tension.
• I did not obtain direct confirmation of US 7,021,148's (Baxter) or DE 198 14 101's full text (search steps were exhausted); their treatment above is based on their titles/abstracts as listed in the citation record and should be verified against the full documents before being relied on as quoted art.
• All reference citations are to the sources linked in Section 3 (Google Patents / FreePatentsOnline / EPO publication server).