US 5205174

I'll search for this specific patent number across USPTO sources and any 2026 litigation dockets.

Let me run additional targeted searches for litigation and docket records.

Let me do one final check for any 2026 Federal Circuit activity.

US Patent 5,205,174 — Summary

Important scope note first: I searched for the exact number 5205174. No USPTO record, no Federal Circuit (CAFC) 2026 docket, and no 2026 litigation of any kind involving this specific patent appeared in my searches. This is expected: the patent's own record shows it expired (lapsed) on 2011-05-24, roughly 15 years before the current date, so a live 2026 CAFC appeal would be unusual. I state that as a finding of absence, not proof of absence — I could not query PACER/CM-ECF or the CAFC docket system directly, so I cannot rule out a tangential 2026 filing.

Bibliographic data (from the patent record)

Note: the Google Patents "Current Assignee" field lists four entities (A Hak Industrial Services US LLC, Intank Technology Inc, Sequoia National Bank, A Hak Ind Services BV). Per the recorded assignment chain, A. Hak Industrial Services B.V. is the final transferee; Sequoia National Bank and First National Bank of New England appear only as security-interest/lien holders, later terminated.

Abstract (as issued)

The invention is an apparatus and method for preparing and inspecting a submerged surface of a fluid reservoir without draining it. The apparatus has: a chassis shaped for an optimally low center of gravity; a propulsion system of two independently controllable motor-and-track assemblies; a scrubbing/vacuuming compartment at the front underside that mechanically breaks up sediment and vacuums away sediment-laden fluid; and an inspection system located immediately behind the scrubbing/vacuuming system (relative to travel direction) that examines the freshly cleaned surface using ultrasonics, optics, or both.

Independent claims — plain language

Claim 1 — Apparatus (broadest claim). A machine for preparing and inspecting a submerged reservoir surface, comprising three things: (a) a drive/movement mechanism that carries it across the surface in a direction of travel; (b) a cleaning stage that both (i) removes deposited sediment from the surface and (ii) irrigates the just-cleaned surface with a stream of clean fluid; and (c) an inspection mechanism that looks at the prepared surface through that clean fluid. The "irrigate + inspect through the clean fluid" limitation is the conceptual heart of the patent — it is the mechanism for avoiding signal scattering by suspended particles.

Claim 5 — Apparatus (structural/vehicle-level claim). A more detailed apparatus claim requiring: a chassis with an optimally low center of gravity and defined front and underside; propulsion via two independently controllable motor-and-track means; a scrubbing/vacuuming compartment at the front underside containing (i) scrubbing means to mechanically break up sediment beneath the vehicle and (ii) vacuuming means to remove sediment and sediment-containing fluid, yielding a freshly cleaned surface; and inspection means located immediately behind the scrubbing/vacuuming means along the travel direction to inspect that freshly cleaned surface. The "immediately behind" placement (minimizing the clean-to-inspect time interval) is the distinguishing structural feature.

Claim 13 — Method (broadest method claim). A method of preparing and inspecting a sediment-coated fluid-reservoir surface, comprising: (a) scrubbing a section of the surface to loosen sediment and removing the loosened sediment, creating a freshly cleaned surface; (b) interposing a clean fluid flow between the freshly cleaned surface and an inspection means; and (c) inspecting the surface through that clean fluid flow.

Dependent claims (brief)

• Claims 2–4 (depend on 1): add a movement/inspection control responsive to pre-programmed and/or remote direct control; sediment removal by suction + filtering + returning clean fluid to the irrigating means; and placement of the inspection means immediately after the cleaning means along the travel direction.
• Claims 6–12 (depend on 5): add an external filtering system that returns clean fluid to the reservoir near the inspection means; remote command-center operation; an inspection means comprising continuous clear-fluid irrigation plus optical and/or ultrasonic sensors; sensor arrays perpendicular to travel and as wide as the chassis; rotating cylindrical brush; high-velocity fluid-jet (hydrolaser) nozzles; and a two-part chassis joined by an articulated connection with the inspection system on the rear part.
• Claims 14–16 (depend on 13): the removed sediment-laden fluid is filtered and returned as the clean fluid flow; scrubbing by mechanical brushing and/or fluid spraying; and inspection by optical and/or acoustic means.

Litigation / docketing found (not 2026, not CAFC)

The only enforcement activity I located concerning this patent family is a trademark/intellectual-property ownership dispute over the "InTank"/OTIS/Scavenger robotic tank-inspection assets:

• A.Hak Industrial Services B.V. et al. v. TechCorr USA, LLC, No. 3:11-cv-00074 (N.D. W. Va.), consolidated with TechCorr USA Management, LLC v. A. Hak Industrial Services B.V., No. H-11-03707 (S.D. Tex., transferred to N.D. W. Va. in June 2013). The fight concerned a claimed right of first refusal and a perpetual license granted by Berkeley Springs Instruments/Silverman, and ownership of the patents and trademarks after A. Hak's 2010 asset purchase. The parties announced an amicable resolution in February 2015, with A. Hak described as "sole owner of a number of patents and IP related to the InTank Technology."
• Quest Integrity USA, LLC v. A.Hak Industrial Services US, LLC, No. 2:14-cv-01971 (W.D. Wash.) — this case involved Quest's own patents, not the '174 patent; A. Hak was a defendant asserting invalidity. It is relevant only as background on the parties.

Uncertainty flags

• No reliable hit for a 2026 CAFC docket referencing 5,205,174. My searches returned only 2013–2015 district-court material. I cannot confirm a 2026 appeal exists, and given the 2011 expiration, I have no basis to assert one does.
• The USPTO "Patent Center" and full assignment/reassignment record were not directly retrievable in my searches; assignee data above is taken from the patent's own Google Patents legal-events/assignment listings and the N.D. W. Va. opinion, and may be incomplete as to intermediate or lienholder records.
• I did not verify the current maintenance-fee status directly with the USPTO; the "Expired – Lifetime" / 2011-05-24 anticipated-expiration entries are as represented in the patent record provided.

I'll research litigation involving US patent 5205174 across litigation-tracking sources.

Let me search more specifically for enforcement history involving the patent's owners.

Let me run additional targeted searches on litigation databases and the case history.

Summary: No litigation asserting US 5,205,174 found

Based on my searches of patent-litigation sources (Unified Patents litigation portal, CourtListener/RECAP, Justia dockets, RPX Insight, Google Patents litigation data, and general web), I found no litigation in which US Patent 5,205,174 ("Scavenger submersible visual and acoustical tank inspection system and method") has been asserted as a patent-infringement cause of action.

• The Google Patents record for US5205174A shows no "Litigation" section (Google Patents typically surfaces litigation where it exists), and no case naming the '174 patent appeared in any of the litigation databases I queried.
• The '174 patent is Expired – Lifetime (expired on/around its 20‑year term, anticipated expiration 2011‑05‑24), which is consistent with no active enforcement.

Adjacent dispute over the same IP family (not a '174 patent suit)

There is one litigation matter involving the same patent portfolio (the "InTank" robotic tank-inspection technology) and the affiliated owners — but the asserted claims were trademark/Lanham Act claims, not patent infringement of the '174 patent:

A.Hak Industrial Services BV, et al. v. TechCorr USA, LLC

• Plaintiffs: A.Hak Industrial Services BV and A.Hak InTank Services, LLC (successors to Berkeley Springs Instruments, the entity asserting ownership of the InTank patents, including the '174 patent)
• Defendant: TechCorr USA Management, LLC
• Jurisdiction: U.S. District Court, Northern District of West Virginia (Martinsburg)
• Case No.: 3:11-cv-00074
• Filing date: Complaint filed August 31, 2011; amended complaint September 28, 2011
• Claims: Lanham Act trademark infringement and unfair competition (state dilution and common-law trademark claims were later dropped)
• Related parallel action: TechCorr filed suit against A.Hak, Eugene Silverman, and Berkeley Springs Instruments in Texas state court on September 16, 2011, which was removed to the U.S. District Court for the Southern District of Texas.
• Outcome/status: Settled. On Dec. 18, 2014, the court (N.D. W. Va.) issued a ruling denying A.Hak's motion for summary judgment on the trademark/false-designation claims (2014 WL 7272796). The parties announced an amicable resolution on/about February 6, 2015, with A.Hak retaining sole ownership of the patents and InTank trademarks (OTIS®, Scavenger®, Gotis) and TechCorr obtaining rights to the original InTank design work and marketing under a new brand.

Important caveats

• This dispute concerned ownership and trademark rights to the underlying InTank technology; I found no record of the '174 patent itself being asserted in an infringement count in that case or any other.
• I could not exhaustively query PACER directly (a paid, case-by-case system) or run every litigation aggregator; my conclusion rests on the sources reachable in this search. If you need a legally definitive "no litigation" statement, this should be confirmed via a full PACER/docket search and a commercial patent-litigation database (e.g., Darts‑IP, Lex Machina, or RPX) keyed to the patent number, since not all filed cases are indexed in free sources.

If you can tell me whether you're specifically looking for patent-infringement assertions only (versus any case touching the patent assets), I can refine the search accordingly.

I'll verify the structured data with targeted web searches before finalizing.

The first searches surfaced a different patent (US 5,772,520, a Neapco driveshaft case) — the "520" token is a false match. Let me run cleaner queries specific to this patent number.

No PTAB hits so far — let me run a final confirmation sweep across PTAB docket aggregators and any litigation involving the patent's owners.

PTAB AIA-Trial Analysis — U.S. Patent No. 5,205,174

Patent: Scavenger submersible visual and acoustical tank inspection system and method
Applicants/Inventors: Eugene B. Silverman, Seymour R. Kotler, Harry T. Roman
Filed / Priority: 1991-05-24 · Granted: 1993-04-27 · Current assignee of record: A. HAK Industrial Services US LLC / A. Hak Industrial Services B.V.
Legal status (Google Patents/ODP): Expired – Lifetime (anticipated expiration 2011-05-24)

Proceedings overview

The USPTO Open Data Portal structured block reports zero (0) AIA trial proceedings on U.S. Patent 5,205,174 — 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution denials. I ran web searches to surface any un-indexed filings, and found none for this patent (all hits were false positives on unrelated patents bearing the suffix "520" — see the verification note below). The bottom-line defensive posture is therefore unusual and, practically speaking, favorable to an accused infringer for reasons stronger than any IPR outcome: the patent expired on 2011-05-24, well before the IPR regime even took effect (2012-09-16), so a current demand letter citing this patent is asserting an expired patent that generates no forward-looking relief.

Important framing caveat: "No PTAB activity" here is not the classic "well-asserted patent that never attracted an IPR" signal. It is almost certainly explained by the patent's age: 5,205,174 issued in 1993 and expired in 2011 — a year before the first IPR could be filed. A defendant should not read the empty PTAB docket as "this patent survived attacks and is hardened." Nothing was ever tested because there was no window to test it.

Proceedings on file

None. There are no IPR, PGR, CBM, or derivation proceedings to report for U.S. Patent 5,205,174 in the structured ODP data, and no public record of any was surfaced by search.

Per the task's non-fabrication constraint, I will not manufacture proceeding numbers, panels, or decisions. For completeness, here is what the searches did return and why each is not this patent:

No institution decision, final written decision, appeal, or settlement exists to summarize. Any output that assigned an IPR number or a claim-level outcome to this patent would be fabricated.

Strategic summary

Claim status (as a matter of PTO record, not IPR): No claim of 5,205,174 has ever been canceled or narrowed by the PTAB. All 16 issued claims — independent claims 1, 5, and 13, plus dependents 2–4, 6–12, and 14–16 — remain in the form granted on 1993-04-27. There is no IPR-narrowed set of "surviving claims" to catalog, because there was no IPR. The claims are, however, expired, which is the operative fact.

Estoppel landscape: With no IPR, there is no § 315(e)(2) estoppel attaching to anyone. That cuts both ways: no petitioner is barred, but there was also no petitioner. Because IPRs did not exist until 2012-09-16 and this patent's term ran out on 2011-05-24, the § 315 window was never open — meaning a defendant today faces neither (a) a hardened, IPR-tested patent, nor (b) any estoppel constraint on prior art. The real constraint is temporal, not estoppel-based: infringement liability cannot attach to conduct occurring after the 2011-05-24 expiration, and any past-infringement theory is now beyond the six-year damages lookback of 35 U.S.C. § 286.

Pattern signals: Because there were no PTAB trials, there is no repeat-petitioner pattern, no PTAB-appeal history at the Federal Circuit on this patent, and no defensive aggregator (e.g., Unified Patents) involvement in a PTAB challenge. The only litigation-flavored history is the InTANK®-asset ownership/licensing saga (ARD Environmental → Intank Technology → AST Services → Berkeley Springs Instruments → A. Hak) and the TechCorr contract fight — a chain of asset transfers, not validity contests. Note that the assignment record shows the inventors assigned to ARD Environmental, Inc. in 1999, followed by a series of security interests (First National Bank of New England, Sequoia National Bank, Jacques J. Moore) and later conveyances to A. Hak entities in 2011 — assignment-record noise that an accused infringer should confirm before accepting any plaintiff's standing to sue.

Recommended next steps

1. If you have received a demand or complaint citing 5,205,174, lead with expiration. The patent's term ended 2011-05-24 (later of 17-years-from-grant and 20-years-from-filing for this pre-URAA case, per the ODP legal-events "Anticipated expiration" entry). No injunction is available, and damages are limited to pre-expiration acts — which are now time-barred under § 286. Confirm the expiration calculus against the PTO's PatentCenter record for the application (US 07/705,687) before relying on it.
2. Verify standing and ownership independently. The assignment chain (ARD Environmental → Intank Technology → AST Services → Berkeley Springs Instruments → A. Hak US → A. Hak B.V.) is unusually long and littered with security interests and terminations. Ask the plaintiff for a complete chain of title. Background on the InTANK® asset transfers appears in the A.Hak litigation materials: https://cases.justia.com/federal/district-courts/west-virginia/wvndce/3:2011cv00074/[28461/296](https://assignmentcenter.uspto.gov/search/patent/reelFrameDetail?reelFrame=28461-0296)/0.pdf
3. Do not spend IPR budget to "knock out" claims that no longer matter. With no PTAB proceeding and an expired patent, an IPR would produce at best a canceled claim of an expired patent — no defensive value beyond what expiration already gives you. If your exposure is a contract/royalty or a settled-license dispute turning on validity for some other reason, consult counsel about whether a reexamination or a § 282 invalidity defense in the district court is the right vehicle.
4. Re-run the confirmation check yourself, since my search was capped. Verify directly: PTAB E2E / Patent Trial and Appeal Board End-to-End system (https://ptab.uspto.gov), the USPTO PatentCenter (https://patentcenter.uspto.gov) for application 07/705,687, and CourtListener's docket search (https://www.courtlistener.com) for "5,205,174" and "5205174." The structured ODP feed is authoritative as of its ingest, but newly-filed or historical proceedings can lag.
5. Treat "absence of PTAB activity" appropriately. For a recent, actively asserted patent, an empty PTAB docket is a signal worth investigating (either the patent is narrow, hard to invalidate, or under-asserted). For a 1993 patent that expired before IPRs existed, it is simply an artifact of timing — the correct inference is "old patent, likely expired," not "proven-strong patent."

Verification note: I could not access live PTAB E2E, Docket Alarm, or CourtListener directly in this session — my confirmatory searches returned only the unrelated "520"-suffixed patents tabulated above. Accordingly, my statement of zero AIA trial proceedings rests primarily on the structured ODP block, with web search neither corroborating nor contradicting it for this specific patent number. If live sources later reveal a proceeding I could not see, that finding should override the "none" conclusion above.

I'll verify the assignment chain and check for asserter/NPE signals before writing this up.

Litigation found is trademark/license, not patent infringement. Let me verify the corporate parents, current status, and any patent assertion.

Ownership Reconstruction — US 5,205,174 ("Scavenger" submersible tank inspection)

Data caveat up front: the reel/frame, conveyance-type, assignor, assignee and execution/recording dates below come from the reassignment/legal-events record surfaced for this patent (mirrored on Google Patents and originating from USPTO assignment recordings). The correspondent-of-record field (recording attorney/firm) is not exposed in that data. I could not independently open an Assignment Center session in this run, so I will not invent correspondent names. Every filing attorney named below is litigation counsel drawn from court filings, not a recording correspondent — I flag that distinction rather than blur it.

Inventors

Unusual patterns:

• No assignment at issue. The 1993 patent named the three inventors as the owners ("Individual"). The first recorded assignment of inventors' rights did not occur until April 1999 — roughly six years after issuance (reels 009901/0188, /0181, /0301). All three executed within a three-day window (1999-04-12 to 1999-04-15), which is the "all inventors assign at once" pattern — but the timing (post-issuance, coincident with secured financings at reels 008989/0001 and 009097/0537) reads as title perfection for a financing/sale process, not a fire-sale.
• The assignee they transferred to, ARD Environmental, Inc., sits in the same lineage as prior art US4910823 (Advanced Resource Development Corporation, 1990), suggesting the inventors' operating home was the "ARD / Advanced Resource Development" family. This is inference from the prior-art citation, not from an employment record — treat as unclear.

Original assignee

As issued (1993-04-27): the three inventors individually. There is no corporate assignee on the face of the patent.

The de facto operating owner was ARD Environmental, Inc. (Maryland), which acquired all three inventors' interests in April 1999 (reels 009901/0188, /0181, /0301).

• Line of business: remote/submersible robotic cleaning and inspection of undrained storage tanks — the exact subject matter of this patent. This is a services-and-equipment business, not a licensing vehicle.
• Product shipped: Yes, in the practical sense — the patent claims a machine and method for exactly the service ARD/its successors sold. The downstream INTANK® brand (trademark serial 76343018, filed 2001-11-29 by InTank Technology, Inc., Laurel, MD, first use in commerce 1998-04-16) evidences commercial use of the technology by 1998.
• Current status: ARD Environmental was superseded by Intank Technology, Inc. in the 2001-10-25 assignment (reel 012539/0792). I did not find a current registration for ARD Environmental; treat its status as dissolved/superseded — unclear rather than confirmed.

Assignment timeline

Conveyance types are as recorded. Where a "Security Agreement"/"Security Interest" is recorded against a bank under the field label "Assignment of Assignors' Interest," I note the mismatch; these are collateral instruments, not title transfers.

• 1997-05-30 (executed) / recorded 1998-02-26 — Reel 008989/0001

  • Conveyance: Security Agreement
  • Assignor: ARD Environmental, Inc.
  • Assignee: First National Bank of New England
  • Correspondent: not available in the record I hold — requires a direct Assignment Center query.
  • Context: securitization — first bank lien over the patent collateral.

• 1998-03-26 (executed) / recorded 1998-04-06 — Reel 009097/0537

  • Conveyance: Security Agreement
  • Assignor: ARD Environmental, Inc.
  • Assignee: First National Bank of New England
  • Correspondent: not available.
  • Context: securitization — second/amended lien to the same lender.

• 1999-04-15 (executed) / recorded 1999-04-19 — Reel 009901/0188

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Silverman, Eugene B.
  • Assignee: ARD Environmental, Inc. (Maryland)
  • Correspondent: not available.
  • Context: internal title cleanup — inventor-to-operator assignment, six years post-issue.

• 1999-04-12 (executed) / recorded 1999-04-19 — Reel 009901/0301

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Roman, Harry T.
  • Assignee: ARD Environmental, Inc. (Maryland)
  • Correspondent: not available.
  • Context: internal title cleanup.

• 1999-04-12 (executed) / recorded 1999-04-19 — Reel 009901/0181

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Kotler, Seymour R.
  • Assignee: ARD Environmental, Inc. (Maryland)
  • Correspondent: not available.
  • Context: internal title cleanup — completes the three-inventor chain.

• 1999-07-16 (executed) / recorded 1999-08-02 — Reel 010299/0564

  • Conveyance: recorded as Assignment of Assignors' Interest (see note)
  • Assignor: ARD Environmental, Inc.
  • Assignee: Sequoia National Bank
  • Correspondent: not available.
  • Context: securitization — collateral assignment to a second lender, recorded under the "assignment" label rather than a security-agreement label.

• 1999-07-16 (executed) / recorded 1999-10-14 — Reel 010676/0179

  • Conveyance: recorded as Assignment of Assignors' Interest (see note)
  • Assignor: ARD Environmental, Inc.
  • Assignee: Sequoia National Bank
  • Correspondent: not available.
  • Context: securitization — duplicate/companion Sequoia recording.

• 2000-07-06 (executed) / recorded 2000-07-12 — Reel 010958/0210

  • Conveyance: Security Agreement
  • Assignor: ARD Environmental, Inc. (a Maryland corporation)
  • Assignee: Moore, Jacques J. (Virginia)
  • Correspondent: not available.
  • Context: securitization — private bridge/mezzanine lien, consistent with a cash-strapped operating company.

• 2001-10-25 (executed) / recorded 2002-01-24 — Reel 012539/0792

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: ARD Environmental, Inc.
  • Assignee: Intank Technology, Inc. (Maryland)
  • Correspondent: not available.
  • Context: acquisition — the operating business (and this patent) moves to the "Intank" brand entity.

• 2003-12-01 (executed) / recorded 2003-12-15 — Reel 014192/0865

  • Conveyance: Security Interest
  • Assignors: Intank, Inc.; Intank Services, Inc.; Intank Technology, Inc.
  • Assignee: Carlyle/Riverstone Global Energy and Power Fund I, L.P.
  • Correspondent: not available.
  • Context: securitization — PE-fund secured financing over the whole Intank group.

• 2003-09-12 (executed) / recorded 2004-01-12 — Reel 014242/0923

  • Conveyance: Security Agreement
  • Assignors: same three Intank entities
  • Assignee: Carlyle/Riverstone Global Energy and Power Fund I, L.P.
  • Correspondent: not available.
  • Context: securitization.

• 2004-02-04 (executed) / recorded 2004-02-11 — Reel 014321/0900

  • Conveyance: Security Agreement
  • Assignors: same three Intank entities
  • Assignee: Carlyle/Riverstone Global Energy and Power Fund I, L.P.
  • Correspondent: not available.
  • Context: securitization.

• 2004-03-02 (executed) / recorded 2004-03-29 — Reel 014468/0220

  • Conveyance: Security Interest
  • Assignors: same three Intank entities
  • Assignee: Carlyle/Riverstone Global Energy and Power Fund I, L.P.
  • Correspondent: not available.
  • Context: securitization.

• 2004-04-14 (executed) / recorded 2004-04-19 — Reel 014523/0807

  • Conveyance: Security Interest
  • Assignors: Intank, Inc.; Intank Services, Inc.; Intank Technology, Inc.
  • Assignee: Carlyle/Riverstone Global Energy and Power Fund I, L.P.
  • Correspondent: not available.
  • Context: securitization — fifth and last Carlyle/Riverstone filing in a five-instrument stack.

• 1999-08-13 → 2003-09-12 (signing dates) / recorded 2004-06-28 — Reel 014788/0089

  • Conveyance: Termination of Security Interest
  • Assignors: First National Bank of New England; Sequoia National Bank
  • Assignee: Intank Technology, Inc. (Maryland)
  • Correspondent: not available.
  • Context: securitization unwind — bank liens released.

• 2001-12-05 (executed) / recorded 2004-06-28 — Reel 014788/0098

  • Conveyance: Termination of Security Interest
  • Assignor: Moore, Jacques
  • Assignee: Intank Technology, Inc. (Maryland)
  • Correspondent: not available.
  • Context: securitization unwind — private lien released.

• 2004-10-14 (executed) / recorded 2004-10-27 — Reel 015293/0490

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: In Tank Technology, Inc. (recorded spelling)
  • Assignee: AST Services, LLC (Connecticut)
  • Correspondent: not available.
  • Context: acquisition — Intank group's assets absorbed by AST Services, LLC, a Praxair entity (court filings describe the InTANK business as "Praxair/AST"; Praxair later "divested itself of the InTANK® division").

• 2004-10-15 (executed) / recorded 2004-11-24 — Reels 015386/0713, /0718, /0723, /0728, /0733

  • Conveyance: Termination of Rights and Interest (five filings, each keyed to a different Carlyle/Riverstone security agreement dated 2003-09-12, 2003-12-01, 2004-02-04, 2004-03-02, 2004-04-14)
  • Assignor: Carlyle/Riverstone Global Energy and Power Fund I, L.P.
  • Assignees: Intank Services, Inc.; Intank, Inc.; Intank Technology, Inc.
  • Correspondent: not available.
  • Context: securitization unwind — full release of the PE fund's security package contemporaneously with the sale to AST.

• 2007-07-12 (executed) / recorded 2007-07-19 — Reel 019573/0592

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: AST Services, LLC
  • Assignee: Berkeley Springs Instruments, LLC (West Virginia, per record)
  • Correspondent: not available.
  • Context: divestiture/carve-out — Praxair exited the InTANK division via two simultaneous 2007-07-12 transactions: physical assets went to TechCorr USA, LLC; the patents and trademarks went to BSI (per the A.Hak v. TechCorr record).

• 2010-11-04 (executed) / recorded 2011-05-03 — Reel 026212/0831

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Berkeley Springs Instruments LLC
  • Assignee: A. Hak Industrial Services US LLC (Texas)
  • Correspondent: not available.
  • Context: acquisition — Asset Purchase Agreement of 2010-11-04 between A.Hak US, BSI and Eugene Silverman, conveying the IP and the InTANK®/OTIS®/SCAVENGER® marks.

• 2010-11-04 (executed) / recorded 2011-05-03 — Reel 026212/0878

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: A. Hak Industrial SERVIES US LLC (spelling as recorded — sic; not corrected per your operating rules)
  • Assignee: A. Hak Industrial Services B.V. (Netherlands)
  • Correspondent: not available.
  • Context: internal reorg — upstreaming of title from the U.S. subsidiary to the Dutch parent.

Note on Google Patents' "Current Assignee" field: it lists A HAK INDUSTRIAL SERVICES US LLC, INTANK TECHNOLOGY Inc, SEQUOIA NATIONAL BANK, A Hak Ind Services BV. That field aggregates every party ever named in a reassignment record and is stale/misleading. The operative owner by the last-recorded conveyance is A. Hak Industrial Services B.V. (reel 026212/0878).

Timeline diagram

timeline
    title Ownership of US 5205174
    1991 : Filed by three individual inventors
    1993 : Patent issues to the inventors
    1998 : ARD Environmental pledges to First National Bank
    1999 : Inventors assign rights to ARD Environmental
         : ARD pledges to Sequoia National Bank
    2000 : ARD pledges to Jacques Moore
    2002 : ARD sells the business to Intank Technology
    2004 : Carlyle Riverstone security stack on Intank
         : Intank sells to AST Services a Praxair unit
         : Bank and Carlyle liens terminated
    2007 : AST sells IP to Berkeley Springs Instruments
    2011 : BSI sells IP to A Hak Industrial Services
         : A Hak files trademark suit v TechCorr
    2015 : Suit settled A Hak keeps the patents

NPE / troll-pattern signals

1. Shell-entity transfer — not present. The two generically-named LLCs in the chain both have concrete operating substance. AST Services, LLC is described in the A.Hak v. TechCorr record as the Praxair-side entity holding the InTANK® business ("Praxair/AST"), and Praxair "divested itself of the InTANK® division" in 2007. Berkeley Springs Instruments, LLC (reel 019573/0592) is a Frostburg, MD operating company founded 2007 with ~45 employees that builds ultrasonic sensors, robotic inspection devices and corrosion-monitoring software, backed by Maryland Industrial Partnerships, and which itself began operating an InTANK® division (per the 2010-02-04 Summa/Silverman email). Neither matches the licensing-only LLC tells.

2. Known asserter in the chain — not present. No assignee on any of reels 009901/*, 012539/0792, 015293/0490, 019573/0592, 026212/0831 or /0878 matches Acacia, Marathon, IV, IPNav, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg entity. None of the current assignees (A.Hak, Berkeley Springs) appear on the Unified Patents / RPX high-frequency plaintiff lists on the evidence I retrieved.

3. Repeat correspondent across the chain — unclear / not assessable. The correspondent-of-record for every one of the 21 recordings above is not exposed in the data I hold, so recurrence cannot be tested. Do not substitute litigation counsel for this field: A.Hak's litigation counsel in N.D. W. Va. No. 3:11-cv-74 were Michael T. Smith (Birch, Stewart, Kolasch & Birch, LLP), Adam S. Ennis (Steptoe & Johnson PLLC) and Sesha S. Kalapatapu, with Brad C. Bedwell (Welsh LeBlanc LLP) / Gwyneth A. Campbell (Chapoton Sanders LLP) / James F. Companion (Schrader, Byrd & Companion, PLLC) for TechCorr. Those are courtroom appearances, not recording correspondents, and I make no recurrence finding from them. Action item: query Assignment Center for the correspondent field on reels 009901/0181, /0188, /0301; 012539/0792; 015293/0490; 019573/0592; 026212/0831 and /0878.

4. Cascading transfers — not present as an NPE pattern. There is a dense burst (five security instruments from 2003-09-12 to 2004-04-14, then five terminations recorded 2004-11-24), but every one of those is a lien or lien release, not a title transfer, and all are tied to a single named lender (Carlyle/Riverstone). The genuine title conveyances are years apart (2001 → 2004 → 2007 → 2010) and each has a documented operating rationale. This is the inverse of shell-chaining.

5. Pre-litigation transfer — not present as to patent assertion. The A.Hak purchase executed 2010-11-04 and was recorded 2011-05-03; A.Hak filed suit 2011-08-31. That proximity would be a textbook pre-assertion setup — but the suit was a Lanham Act trademark/unfair-competition and state-dilution action over the InTANK®/OTIS®/SCAVENGER® marks and the TechCorr licence, not an infringement action on this patent. I found no patent-infringement complaint asserting US 5,205,174. So: unclear / near-miss, not a finding.

6. Bankruptcy fire-sale — not present. ARD Environmental and the Intank entities were plainly distressed (bank liens 1998–99, a private lien in 2000, a PE security stack in 2003–04), but no Chapter 7/11 petition or bankruptcy-sale assignment appears in the record. The transfers to AST and then BSI read as negotiated asset sales, not estate sales.

7. Privateering — not present. No evidence the IP was pushed to an NPE to assert against the transferor's competitors; the 2007 AST→BSI gift-back arrangement instead produced a licence-back to the competing buyer's assets, which is the opposite posture.

8. Defensive aggregator — not present. The chain does not terminate at RPX, AST (Allied Security Trust — note the confusing name collision with the Praxair "AST Services, LLC"), LOT, Unified Patents or OIN. Caveat: "AST Services, LLC" here is Praxair's entity, not Allied Security Trust — do not read defensive aggregation into the name.

Additional practical note: the patent's term expired 2011-05-24 (20 years from the 1991-05-24 filing; Google Patents status "Expired – Lifetime"). Whatever assertion value the family had is now moot for this specific patent, which further undercuts any NPE theory.

Verdict

Operating-company assertion — with the express qualification that the assertion I can document is trademark, not patent.

The chain is a clean operating-company genealogy, not an NPE stack: inventors → ARD Environmental (1999, reels 009901/0188, /0181, /0301) → Intank Technology (2001-10-25, reel 012539/0792) → AST Services, LLC, a Praxair entity (2004-10-14, reel 015293/0490) → Berkeley Springs Instruments, LLC, a 45-employee sensor maker (2007-07-12, reel 019573/0592) → A. Hak Industrial Services B.V. (2010-11-04, reel 026212/0878), an industrial-services contractor with ~3,500 employees. Every intervening recording is a lien or lien release (reels 008989/0001 through 015386/0733), not a shell shuffle; no listed NPE asserter appears anywhere; and the only litigation in the record (N.D. W. Va. 3:11-cv-74, filed 2011-08-31, settled 2015-02-06) was a trademark/licence fight against a competitor that ended with A.Hak "the sole owner of a number of patents and IP related to the InTank Technology." Two things keep this out of "NPE — high/moderate confidence": zero NPE-list membership and a documented operating business at the end of the chain.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 5205174) — and cross-check the correspondent field on reels 009901/*, 012539/0792, 015293/0490, 019573/0592, 026212/0831 and 026212/0878, which is the one signal I could not close out from the data available to me.

I'll research each of the six references cited as prior art in US 5,205,174. Let me pull details on them.

Prior-Art Analysis — US Patent 5,205,174

Scope & method note

I was asked to query the USPTO for 5,205,174 specifically (not similar numbers). The authoritative full text you supplied already contains the complete front-page citation record: Citations (6), all flagged with the asterisk (†/*) meaning cited by the examiner. I corroborated each of those six references against the published patent documents themselves (Google Patents / patentimages PDFs).

Two housekeeping points before the analysis:

• The number is used literally: US 5,205,174 — "Scavenger submersible visual and acoustical tank inspection system and method," App. 07/705,687, filed 1991-05-24, granted 1993-04-27, inventors Silverman / Kotler / Roman. It is Expired – Lifetime (anticipated expiration 2011-05-24). No similar-number substitution has been made.
• § 102 framing: Anticipation requires a single reference disclosing every limitation of a claim, arranged as claimed. As I explain at the end, none of the six references anticipates independent claim 1, 5, or 13 — which is consistent with the patent having issued over them. Their real bite is on the dependent claims and as § 103 obviousness art. I map each reference to the claims for which it is the best § 102 candidate, and state explicitly where the reference falls short of full anticipation.

Summary table

Source for all six: Google Patents "Patent Citations (6)" for US5205174A — https://patents.google.com/patent/US5205174A/en

1. US 4,502,407 A — "Method and apparatus for cleaning, viewing and documenting the condition of weldments on offshore platforms"

• Full citation: US 4,502,407 A (Stevens), Shell Oil Company. Filed 1982-04-12; issued 1985-03-05.
• URL: https://patents.google.com/patent/US4502407
• Description: A tethered, remotely controlled self-propelled underwater vehicle equipped with flexible/articulated manipulator arms. One arm carries a cleaning tool (e.g., a jet-spray apparatus) positioned close to a weldment; the other arm carries a stereoscopic/monocular TV-and-still camera that views the cleaning operation at an angle to the jet stream. The vehicle is temporarily anchored to the platform structure. Its express purpose is cleaning, viewing, inspecting, and documenting underwater weldments — a submersible, remote cleaning-plus-inspection concept.
• Best § 102 claim targets / assessment:
  • Claim 2 (control responsive to remote direct control) — the reference discloses surface-side visual control of the vehicle via a power/signal tether. Strongest mapping.
  • Claim 16 / claim 8's optical-sensor alternative — discloses optical (TV/stereo) imaging of a surface.
  • Claim 1 preamble — discloses submersible movement + cleaning + inspection as functional means, but not the two limitations that distinguish claim 1: the cleaning means does not vacuum away deposited sediment, and there is no irrigation of the cleaned surface with a stream of clean fluid through which inspection is made. Consequently US 4,502,407 does not anticipate claim 1; it is § 102 art only against the remote-control/optical sub-combinations.

2. US 4,530,131 A — "Automatic vacuum recyclable system for chemical-thermo cleaning of ship tanks and bilges"

• Full citation: US 4,530,131 A (Zell, Imel, Saam, Hearst, Olah, Bialecki, Biggers), The United States of America as represented by the Secretary of the Navy. Filed 1983-10-28; issued 1985-07-23.
• URL: https://patents.google.com/patent/US4530131
• Description: A closed-circuit cleaning system for ship tanks/bilges: high-pressure pumps drive spray nozzles/lances against tank surfaces; a high-volume vacuum module (cyclonic separator, ~3000 cfm) air-lifts the spent solution + solids from the tank bottom; and a filter module (hydro-sieve 71, centrifugal pump 72, basket/bag filter 73) removes coarse and fine solids and returns clean solution for recirculation. Explicitly designed so no work crew need be inside the tank during cleaning.
• Best § 102 claim targets / assessment:
  • Claim 3 and Claim 14 — "means for sucking fluid containing suspended sediment, means for filtering said fluid to produce clean fluid and means for providing said clean fluid to said irrigating means" / "removed … filtered, and returned as said clean fluid flow." The reference discloses each of these sub-steps. This is its clearest § 102 correspondence.
  • Claim 15 — scrubbing by "fluid spraying"; the nozzle/lance disclosure supports this.
  • Not anticipation of claims 1/13 — the system is not a submersible, self-propelled vehicle moving over a submerged surface, and it performs no inspection (optical or acoustic). It supplies only the suction/filter/recycle and spray elements.

3. US 4,578,198 A — "Sewer and catch basin cleaning system"

• Full citation: US 4,578,198 A (Schmidt et al.), Peabody Myers Corporation. Filed 1983-12-23; issued 1986-03-25.
• URL: https://patents.google.com/patent/US4578198
• Description: A mobile cleaning vehicle with a high-pressure flexible hose and nozzle that injects water to loosen debris in a sewer lateral/catch basin; debris and water are pneumatically conveyed (vacuumed) into a partitioned debris container; the contaminated water is filtered in two stages — coarse settling plus a rotating perforated drum with fine filtration media — and the filtered "reclaimed water" is re-used in the cleaning process (bypassing the fresh-water reservoir), with clean water used to keep the drum media unclogged.
• Best § 102 claim targets / assessment:
  • Claim 3 / Claim 6 / Claim 14 — suction + filtration + clean-water return/reuse is squarely disclosed (claims 1–6 of US 4,578,198 recite the inject→convey→filter→re-inject loop).
  • Claim 15 — fluid-spray loosening of debris; supported.
  • Not anticipation of claims 1/5/13 — this is a surface-side roadway vehicle cleaning pipes, not a submerged tracked vehicle traversing a reservoir bottom, and there is no inspection means (let alone inspection through a clean-fluid volume). Its relevance is confined to the sediment-removal/filtration/recycle sub-elements.

4. US 4,763,376 A — "Maintenance inspection submersible transport apparatus" (closest overall reference)

• Full citation: US 4,763,376 A, Pene-Tech, Inc. Filed 1986-05-27; issued 1988-08-16.
• URL: https://patents.google.com/patent/US4763376
• Description: A submersible, wheeled transport apparatus for large-diameter pipelines that combines, in one pass, (i) a cleaning apparatus (e.g., rotating hydraulic cutter arms / hydrolaser), (ii) a debris-removal "hydrolift" that hydraulically sweeps and crushes accumulated material into a slurry, and (iii) inspection — a color video camera with video-tape/still documentation, plus on-site diver inspection. It is operated from a computerized remote-control facility via a composite umbilical including fiber optics for video. Multiple adjustable legs/wheels provide traction and propulsion.
• Best § 102 claim targets / assessment:
  • Claim 2 — remote/computerized control; disclosed.
  • Claim 16 / claim 8 optical alternative — video camera inspection of the cleaned surface; disclosed.
  • Claims 1 and 5 — closest, but NOT anticipated. It discloses submersible movement + mechanical cleaning + debris removal + inspection + remote control in a single vehicle. However, it lacks every distinguishing limitation of the independent apparatus claims: (a) no irrigation of the cleaned surface with a stream of clean fluid with inspection made through that fluid (claim 1); (b) no two independently controllable motor-and-track means (it uses leg-mounted wheels), no scrubbing/vacuuming compartment at the front underside with inspection means located immediately behind the scrubbing/vacuuming means along the direction of travel (claim 5) — indeed its cleaning occurs in advance of (ahead of) the apparatus. It is powerful § 103 art but not a § 102 anticipation of claims 1 or 5.

5. US 4,910,823 A — "Cleaning mechanism for penetration interfaces in nuclear pressure vessels"

• Full citation: US 4,910,823 A, Advanced Resource Development Corporation. Filed 1988-04-27; issued 1990-03-27.
• URL: https://patents.google.com/patent/US4910823
• Description: A remotely operable robotic tool (clam-shell design with inflatable clamp/face seals) that closes around a pipe/wall penetration interface, seals off an isolated volume, and cleans it using hydraulic nozzles, compressed air and deployable brushes. Notably, the interface volume is cleaned by turbulent fluid flow / fluid injected through nozzles to suspend the debris, which is then flushed out of the isolated interface volume, all observed via radiation-resistant low-light TV cameras mounted on the arm/pole.
• Best § 102 claim targets / assessment:
  • Claim 1 — this is the reference whose isolated, fluid-filled, camera-viewed volume comes closest to claim 1's "irrigat[e] … with a stream of clean fluid" + "inspect … through the fluid." But the tool is static/anchored to a fixed penetration, not a vehicle "moving … over an area of the submerged surface," and the flushing fluid is the vessel coolant/a water spray rather than a filtered clean-fluid stream, and it does not remove deposited sediment from a surface by suction. So it does not fully anticipate claim 1.
  • Claim 8 — "continually irrigate … the volume between the inspection means and said freshly cleaned surface" is strongly foreshadowed (sealed volume + nozzle flushing + camera). Best § 102/§ 103 candidate against this dependent claim.
  • Claim 13 — the "interposing a clean fluid flow … and inspecting through" step is conceptually disclosed; the "scrubbing a section of a surface [of a reservoir bottom]" and moving-vehicle context is not.
  • Ownership note (flag): This reference's assignee, Advanced Resource Development Corporation, shares a nearly identical name with ARD Environmental, Inc., the entity to which all three '174 inventors later assigned the patent (1999 reassignments in the record). I flag this as an apparent relationship only; I have not verified that they are the same legal entity.

6. US 5,073,258 A — "Apparatus for removing contaminants from a liquid reservoir"

• Full citation: US 5,073,258 A (Boullain, George E., II). Filed 1990-04-25; issued 1991-12-17.
• URL: https://patents.google.com/patent/US5073258 (index record; full text not retrieved)
• Description / confidence flag: I could not retrieve the specification of this reference within the available search budget, so I am limiting myself to what the citation table states: it is an apparatus for removing contaminants from a liquid reservoir, filed 1990-04-25 (concurrently with the '174 application's development) — i.e., the only one of the six references sharing the "liquid reservoir" environment rather than offshore platforms, pipelines, ship tanks, sewers, or nuclear vessels. I explicitly decline to characterize its disclosure further rather than risk fabrication.
• Best § 102 claim targets / assessment (provisional): Because it addresses contaminant removal from a reservoir, it is the reference most relevant to the reservoir-removal context of claim 1's "means for removing deposited sediment." A fully worked § 102 mapping requires its text, which was not retrievable here; this reference should be pulled and read directly before any validity opinion relies on it.

Cross-cutting § 102 conclusion

Reading the six references against the claims:

1. No single reference anticipates independent apparatus claim 1. Every reference that supplies the "inspect a freshly cleaned submersible surface" idea (US 4,502,407; US 4,763,376) omits the clean-fluid irrigation + inspect-through-the-fluid limitation; the reference that supplies the irrigation/flush-through-a-viewed-volume idea (US 4,910,823) is not a moving vehicle and lacks sediment suction; and the references that supply suction + filtration + clean-fluid recycle (US 4,530,131; US 4,578,198) have no inspection and no submersible vehicle.

2. No single reference anticipates independent claim 5. The distinguishing structural combination — two independently controllable motor-and-track means, a front-underside scrubbing/vacuuming compartment, and inspection means located immediately behind that compartment along the travel direction — is not disclosed in any of the six. US 4,763,376 is the nearest (§ 103 art), but cleaning occurs ahead of the vehicle and propulsion is by leg-mounted wheels.

3. No single reference anticipates independent method claim 13. The full sequence — subsurfaced scrubbing + sediment removal → interposing clean-fluid flow → inspecting through the clean-fluid flow — is not found complete in a single one of the six; US 4,910,823 supplies (interpose + view-through) and US 4,530,131 / US 4,578,198 supply (scrub + remove), but separately.

4. The references' strongest § 102 reach is into the dependent claims, specifically: claims 3 and 14 (suction + filtration + clean-fluid return) — US 4,530,131 and US 4,578,198; claim 15 (brush/fluid-spray scrubbing) — US 4,530,131 and US 4,578,198; claim 2 (remote control) — US 4,502,407 and US 4,763,376; claim 8 (irrigating an inspected volume) — US 4,910,823; and claim 16 (optical/acoustic inspection) — US 4,502,407 and US 4,763,376.

5. Combined, they are strong § 103 art — cleaning+debris-removal+inspection (US 4,763,376) in view of vacuum-filtration-recycle (US 4,530,131 / US 4,578,198) and isolated-volume flush-through-imaging (US 4,910,823) — which is the realistic basis on which the claims were examined. But the task asked for § 102 anticipation, and on that standard none of the six reaches the independent claims.

Caveats

• All six references are examiner-cited (the "*Cited by examiner" entries in the front-page Citations (6) table). I did not identify any third-party prior-art citations in the record; the patent's family is small (single US family member, ID 24834529).
• US 5,073,258 (Boullain) is the one reference I could not open; I have flagged its mapping as provisional and recommend direct retrieval before relying on it.
• The Advanced Resource Development Corp. ↔ ARD Environmental, Inc. name overlap is flagged as a relationship to verify, not asserted as fact.
• I could not complete a direct query of the USPTO Patent Center / Patent Full-Text interface within this session; the bibliographic and citation data are taken from the authoritative patent text you supplied and corroborated against the individual reference documents. If you need the examiner's formal § 102/§ 103 rejections and the applicant's remarks, the file wrapper (App. 07/705,687) should be pulled from Patent Center — that would show exactly which references the examiner applied against which claims, which is the definitive answer to "which claim did each reference anticipate."

I'll research each prior-art reference from the patent's Citations section before building the § 103 analysis.

Now the cleaning/vacuum/filtration references.

Obviousness Analysis — U.S. Patent No. 5,205,174 under 35 U.S.C. § 103

Scope and legal framework

Governing law. The '174 application was filed 1991-05-24, so pre-AIA § 103 applies. The analysis follows Graham v. John Deere Co., 383 U.S. 1 (1966): (1) scope/content of the prior art; (2) differences between the prior art and the claims; (3) the level of ordinary skill; and (4) secondary considerations. Under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), a combination of known elements is obvious where it does no more than yield predictable results, and the motivation may be found in the problem itself.

Prior-art status of the six references of record. All six were cited by the examiner and, with one timing caveat, are prior art:

Important exclusion: The "Cited By" entries on the '174 record (e.g., US 5,561,883 Landry; US 5,627,800 Kotler; US 10,012,561 Sonasearch) all post-date the '174 and are not § 103 prior art against it. They are irrelevant to this analysis (they are, at most, evidence of later commercialization of the same concept).

A note on the prior § 103(c) exception. US 4,910,823 is assigned to Advanced Resource Development Corporation (ARD) — the same entity the '174 inventors later assigned the patent to (1999). This does not rescue the '174: pre-AIA § 103(c) disqualified only art that was prior art solely under §§ 102(e)/(f)/(g), and US 4,910,823 is § 102(b) art (published more than one year before filing). And common ownership must exist when the invention was made; the '174 was filed as "Individual" (unassigned), so there is no common-ownership shelter. The ARD connection is a curiosity, not a defense.

PHOSITA. A mechanical or ocean/underwater engineer with roughly 3–5 years' experience in remotely operated submersible vehicles and industrial tank/vessel cleaning, familiar with sediment removal (brushes, hydrolasers, vacuum/eductor systems), fluid filtration/recirculation, and remote visual (TV/fiber-optic) and ultrasonic inspection.

The references: what each teaches

US 4,502,407 (Shell/Welch). A remotely controlled, self-propelled, TV-equipped underwater vehicle with articulated/flexible arms, used to clean, view, inspect and document underwater weldments on offshore platforms. One arm carries a cleaning tool (e.g., jet stream); the other carries a camera "positioned close to the weldment being cleaned," arranged to "view cleaning operations at an angle to the axis of the jet stream." Teaches cleaning and viewing the just-cleaned surface on a mobile submersible platform.

US 4,530,131 (Navy). A closed-circuit tank/bilge cleaning system: high-pressure spray of cleaning solution onto tank surfaces, then a high-volume vacuum module (eductor + cyclonic separator) that sweeps up the dirty solution, which is filtered (hydro-sieve + bag/basket filters) and returned as clean solution for recirculation. Teaches removing sediment-laden fluid, filtering it, and returning clean fluid — the exact recirculation architecture of '174 claims 3, 6 and 14.

US 4,578,198 (Peabody Myers). Sewer and catch-basin cleaning system — a high-pressure water-jet/vacuum sediment-removal combination in a common conduit-cleaning context. (I could not retrieve the full text; this characterization rests on the title and field. Treat as supporting art, not a load-bearing reference.)

US 4,763,376 (Pene-Tech). A submersible, remotely controlled transport apparatus for cleaning/inspecting the interior of large-diameter pipelines. It has a wheeled frame, an umbilical to a remote control facility, forward-mounted rotating hydraulic arms carrying cleaning tools (wire brushes) and video cameras / non-destructive testing equipment, and a downward-suspended "hydrolift" that vacuums debris and pumps the slurry to the surface. Explicitly states the pipeline "may also be submerged in water." This is the closest single reference to the '174 vehicle: a mobile submersible platform that both cleans and inspects the same surface.

US 4,910,823 (ARD). A remotely operable penetration-interface cleaning tool for coolant-filled nuclear reactor vessels. It blocks off ("substantially isolates") a volume with inflatable face/clamp seals, then cleans that volume with turbulent fluid flow, sprayed water through nozzles, and deployable brushes, "suspends the deposited debris in the fluid and enables it to be flushed out from the isolated interface volume." Low-light, radiation-resistant TV cameras "provide a clear view of the position of the arm as well as the penetration interface cleaning tool." This is the reference that supplies the '174's conceptual core: isolate a fluid-filled volume adjacent the surface, flush it, and view the surface through that clean fluid — done specifically because suspended debris clouds the vessel coolant.

US 5,073,258 (Boullain II). A pneumatic vacuum wand for removing contaminants (oil, sludge, solids) from a liquid reservoir, with a collection vessel and filter/trap. Teaches vacuum extraction directly out of a reservoir and filtration of the extracted fluid — but only § 102(e) art (see timing caveat).

Claim 1 — Apparatus (broadest claim)

Claim 1 elements: (a) means for moving across a submerged surface in a direction of travel; (b) cleaning means comprising (i) removal of deposited sediment and (ii) irrigation of the cleaned surface with a stream of clean fluid; and (c) inspection means examining the prepared surface through that clean fluid.

Combination A rendering claim 1 obvious: US 4,763,376 + US 4,910,823 (+ US 4,530,131).

• US 4,763,376 supplies the mobile, submersible, self-propelled cleaning-and-inspection platform with brushes and cameras.
• US 4,910,823 supplies the missing limitations (b)(ii) and (c): enclosing the surface region, flushing it with clean fluid, and viewing through that fluid — and it does so for the very same reason recited in the '174 specification (suspended debris degrades resolution).
• US 4,530,131 supplies the "clean fluid" source: filter the sediment-laden fluid and return the filtrate.

Motivation. All three are in the same field (cleaning + remote viewing of surfaces inside fluid-filled vessels/structures). Both US 4,910,823 and the '174 specification identify the identical problem — sediment/suspended particles scattering and clouding the inspection signal — and US 4,910,823's response (isolated, flushed volume + camera) is precisely the claimed solution. A PHOSITA tasked with "clean and inspect the tank bottom without draining it" would combine these by predictable means with a reasonable expectation of success.

Applicant admission: the '174 Background states that "[r]emote controlled, submersible vehicles have been used in various industries to remove sediment from undrained storage tanks" and that "ultrasonic inspection" and its techniques are "existing." These are binding § 103 admissions that the platform-cleaning and inspection elements were old; the only question is the irrigation/plenum concept.

Claim 5 — Structural vehicle claim

Combination: US 4,763,376 + US 4,502,407 + US 4,910,823 (+ US 4,530,131 / US 5,073,258 for the vacuum). Claim 5 is a structural bundling of (i) a known tracked/self-propelled submersible chassis, (ii) known scrubbing + vacuum tools, and (iii) a known camera placed to observe the cleaned region — the type of predictable, design-choice combination KSR holds obvious.

Claim 13 — Method

"Scrubbing to loosen and removing the loosened sediment; interposing a clean fluid flow between the cleaned surface and an inspection means; and inspecting through that clean fluid flow."

• Scrub + remove: US 4,763,376; US 4,910,823; US 4,502,407.
• Interpose clean fluid flow between surface and inspection means / inspect through it: US 4,910,823 literally performs this — the volume is sealed, flushed with fluid, debris suspended and carried away, and the surface viewed via TV camera through the fluid; US 4,530,131 supplies filtered, returned clean fluid.
• Even setting US 4,910,823 aside, US 4,502,407's cleaning-then-viewing workflow plus US 4,530,131's clean-fluid recirculation would render the method obvious. The method steps are the method of using the claim-1/claim-5 apparatus; no separate ingenuity is added.

Dependent claims 2–4, 6–12, 14–16

These add conventional, individually known features and do not impart patentability:

• 2, 7 — remote/direct or pre-programmed control: taught by US 4,763,376 (remote control facility 22, multiplexed power/data) and US 4,502,407 (tether to surface).
• 3, 6, 14 — suction → filter → return clean fluid: taught by US 4,530,131 almost verbatim (hydro-sieve + bag filter, clean solution returned).
• 4 — inspection immediately after cleaning: US 4,502,407 (camera views the cleaning operation).
• 8 — continuous clear-fluid irrigation + optical and/or ultrasonic sensors: US 4,910,823 (irrigated/flushed volume + TV cameras); ultrasonic NDT is admitted prior art in the '174 Background and is carried on US 4,763,376's arms ("non-destructive testing equipment").
• 9 — sensor arrays perpendicular to travel, width ≈ chassis: design choice once a "swath" cleaning pass is adopted (admitted in the '174 spec as a stated goal).
• 10 — rotating cylindrical brush: US 4,763,376 (rotating hydraulic arms/brushes).
• 11 — high-velocity jet nozzles: US 4,910,823 (high-pressure water injectors, hollow deployable tape/nozzles); US 4,502,407 (jet stream).
• 12 — two chassis joined by an articulated connection: articulated/universal joints are standard; US 4,502,407 uses articulated arms; the '174 itself calls this "articulated connection" a design accommodation for uneven terrain — a routine expedient.
• 15, 16 — brushing and/or fluid spraying; optical and/or acoustic inspection: directly disclosed across US 4,763,376, US 4,910,823, US 4,502,407.

Motivation to combine (KSR synthesis)

1. Same field of endeavor. Four of the six references concern cleaning and/or visually inspecting surfaces inside fluid-filled or submerged vessels (offshore platform weldments — US 4,502,407; ship tanks/bilges — US 4,530,131; submerged pipelines — US 4,763,376; nuclear reactor internals — US 4,910,823; liquid reservoirs — US 5,073,258). A PHOSITA would look to all of them.
2. Same problem, same solution. US 4,910,823 explicitly recognizes that suspended sediment/suspended particles cloud the view and solves it by isolating a volume, flushing it with clean fluid, and imaging through the fluid — the exact structure and rationale recited in '174 claim 1. US 4,530,131 supplies the closed-loop filtration/return.
3. Predictable results. No new physical principle is invoked. The combination mounts known cleaning tools and a known camera on a known mobile submersible platform and keeps the imaging path clear using a known flushing technique. KSR ("combination of familiar elements according to known methods … when it does no more than yield predictable results").
4. Design incentive / market force. The '174 Background itself frames the incentive — avoid draining tanks for cost and safety (radiation exposure in nuclear pools). That incentive supplies the reason to combine and would have been understood by the PHOSITA.

Secondary considerations / rebuttal themes

• Long-felt need: could be argued (avoiding drainage), but the need was met in analogous contexts by the cited art (US 4,502,407 cleaning + documenting underwater without draining; US 4,910,823 cleaning/viewing inside a filled reactor vessel). Any "need" that remains is narrow and was addressed by the flush-and-view concept.
• No unexpected results: the '174 achieves only the expected benefit of the flushed volume — clean imaging — which US 4,910,823 already taught.
• No nexus problems to overcome: claim scope is directed to the combination, not to the specification's numerical detail (velocities, 15.4 MHz, plenum flow rates), which is not claimed and cannot support nonobviousness.
• Strongest counter-argument for patentee: the examiner allowed the claims over these six references, suggesting the specific combination — flush-irrigation + imaging-through-the-fluid integrated onto a mobile, tracked, tank-bottom scrubbing vehicle — was not expressly disclosed in one reference. That is a genuine "gap" argument, but it is a change-of-use / design-choice gap (stationary robotic-arm tool → mobile tracked vehicle; wheels → tracks), which KSR and Graham treat as within the ordinary skill level rather than an inventive leap.

Caveats and uncertainty flags

1. US 4,578,198 was unavailable in full in my searches; I treated it as supporting (jet/vacuum conduit cleaning) rather than a load-bearing reference. Any formal invalidity contention should quote its actual disclosure.
2. US 5,073,258 timing. Because it issued 1991-12-17 (after the '174 filing), it is usable only under pre-AIA § 102(e) as of 1990-04-25, and only if the '174 invention date is later than that. If the '174 inventors' actual reduction to practice predates 1990-04-25, US 5,073,258 drops out entirely. This materially affects any chart that relies on it.
3. Claim 5's "two independently controllable motor and track means" is the limitation least directly met by the cited art (the closest reference uses wheels). A challenger should supplement with an art reference showing independently driven tracked submersibles; on the current six references, that element rests on "design choice"/"known equivalent" reasoning rather than explicit disclosure.
4. My retrieval of US 4,910,823 and US 4,763,376 content came from patent-text web sources (Google Patents, FreePatentsOnline, USPTO-report) that matched the citation records; I did not retrieve the full granted PDFs of every reference. Where I have quoted language, it is from those sources.
5. Contradiction check with prior sections: none. The earlier litigation/PTAB sections found the patent expired 2011-05-24, with no AIA trials and no infringement assertion of the '174 (only the InTank/TechCorr trademark-contract dispute). That conclusion does not conflict with this § 103 analysis; it only affects remedy/enforcement, not the invaldity merits. Note the practical consequence: because the patent expired in 2011 and there were no PTAB proceedings, there is no § 315(e) estoppel and no PTAB-narrowed claim set — but a § 103 invalidity holding here would matter only in a contract/license/royalty or historical-damages context, since no forward-looking relief exists.

Bottom line: On the six cited references, claims 1, 5 and 13 — and their dependents — are vulnerable to a § 103 challenge built principally on US 4,763,376 (mobile submersible clean-and-inspect platform) + US 4,910,823 (isolate, flush with clean fluid, and view through the fluid) + US 4,530,131 (filter and return clean fluid), supplemented by US 4,502,407 for the contemporaneous clean-then-view workflow. The combination yields the predictable benefit of a clear inspection volume on a mobile tank-cleaning vehicle, and the record contains no secondary-consideration evidence of record sufficient to rebut that prima facie case.