Perma-Liner v. NuFlow: Three Pipe Lining Patents, One Settlement After 426 Days
Perma-Liner Industries, LLC filed suit against NuFlow Technologies U.S.A., Inc. in Delaware District Court asserting infringement of three pipe rehabilitation patents across the NuCure Cold Cure UV product line. After 426 days of litigation — including invalidity and inequitable conduct counterclaims from NuFlow — the parties reached a private settlement, resulting in dismissal with prejudice on the asserted claims.
Pipe Rehabilitation Patent War Ends in Confidential Settlement
Perma-Liner Industries, LLC — a pipe lining technology company — filed suit on June 18, 2024, in the District of Delaware against NuFlow Technologies U.S.A., Inc., asserting infringement of three U.S. patents: US11674628B2, US11802647B2, and US12014458B2. The complaint targeted NuFlow’s NuCure Cold Cure UV product, with Perma-Liner alleging infringement of claim 33 of the ‘628 patent, claims 1–10, 12–17, and 19–25 of the ‘647 patent, and claims 1–21 of the ‘458 patent — a broad assertion covering dozens of claims across all three patents.
NuFlow responded with counterclaims of non-infringement, invalidity, and inequitable conduct against all three patents. On August 18, 2025 — 426 days after filing — the parties stipulated to dismissal under Fed. R. Civ. P. 41(a)(2) following entry of a private settlement agreement. Perma-Liner’s infringement claims and NuFlow’s non-infringement and invalidity counterclaims as to the specifically asserted claims were all dismissed with prejudice. NuFlow’s inequitable conduct counterclaim, non-asserted claim validity challenges, and all defenses were dismissed without prejudice.
The asymmetric dismissal structure is commercially significant: with-prejudice dismissal of the asserted claims bars Perma-Liner from re-litigating those specific allegations, while NuFlow’s without-prejudice dismissal of the inequitable conduct claim leaves that avenue theoretically open. The court retains jurisdiction over the settlement agreement itself, suggesting the deal contains ongoing obligations — likely a license or design-around commitment — whose terms remain confidential. The mutual cost-bearing provision is consistent with a negotiated resolution where neither party achieved a clear litigation victory.
Filing to Case Dismissed in 426 days
426 days — consistent with settlement before summary judgment in Delaware patent cases
Settlement dismissal: what the mixed prejudice structure means for both sides
Mixed with/without prejudice dismissal under Rule 41(a)(2)
Under Fed. R. Civ. P. 41(a)(2), the court approved a stipulated dismissal with asymmetric finality. Perma-Liner’s infringement claims and NuFlow’s invalidity counterclaims on the asserted claims are dismissed with prejudice — meaning those specific disputes are permanently resolved. NuFlow’s inequitable conduct claim and challenges to non-asserted patent claims are dismissed without prejudice, preserving those arguments for any future dispute.
Rule 41(a)(2) — court-ordered dismissalPerma-Liner’s three patents survive — validity never adjudicated
Because NuFlow’s invalidity counterclaims on the asserted claims were dismissed with prejudice, NuFlow cannot re-litigate those specific invalidity theories in future Delaware proceedings. Crucially, no court ever ruled the patents invalid, so Perma-Liner retains enforceable IP. The court’s retained jurisdiction over the settlement agreement suggests Perma-Liner may hold ongoing rights — potentially licensing fees or product restrictions — secured through negotiation rather than trial.
Patents remain enforceableNuFlow avoids injunction but retains limited future optionality
NuFlow escaped an adverse infringement judgment, which would have risked injunctive relief against the NuCure Cold Cure UV product line. The without-prejudice dismissal of the inequitable conduct claim is a notable preservation: if a future dispute arises under the settlement agreement, NuFlow could potentially re-assert that the patents were unenforceable due to conduct before the patent office. However, NuFlow’s invalidity arguments on the asserted claims are foreclosed.
Inequitable conduct claim preservedConfidential settlement signals a negotiated coexistence in UV cure pipe lining
The court’s explicit retention of jurisdiction over the settlement agreement — including contract, tort, and statutory disputes — is a strong indicator that ongoing commercial terms were agreed, such as a license, royalty, or field-of-use restriction. Competitors in the cured-in-place pipe (CIPP) and UV-cure lining segment should note that Perma-Liner has now demonstrated willingness to assert its patent portfolio aggressively, and that NuFlow’s product design may now operate under licensed terms.
Likely license or royalty agreedFull party and counsel information
| Role | Name | Type | Detail |
|---|---|---|---|
| Plaintiff | Perma-Liner Industries, LLC | Company | Pipe rehabilitation technology company — holder of US11674628B2, US11802647B2, and US12014458B2Search in Eureka ↗ |
| Defendant | NuFlow Technologies U.S.A., Inc. | Company | NuFlow Technologies U.S.A., Inc. — manufacturer of the NuCure Cold Cure UV pipe lining systemSearch in Eureka ↗ |
| Plaintiff counsel | Calvin E. Wingfield, Jr. | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Jacqueline Genovese Bova | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Jeremy Knight | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Magdalin Pena Jimenez | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Mark J. Abate | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Rodger Dallery Smith , II | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff counsel | Travis J. Murray | Attorney | Counsel for Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Plaintiff law firm | Morris, Nichols, Arsht & Tunnell LLP | Law Firm | Representing Perma-Liner Industries, LLCSearch in Eureka ↗ |
| Defendant counsel | Christian G. Andreu-von Euw | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant counsel | Desmond P. O’Sullivan | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant counsel | Jayson L. Cohen | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant counsel | Karen Elizabeth Keller | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant counsel | Lindsey Michelle Gellar | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant counsel | Nathan Roger Hoeschen | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant counsel | Will B. Fitton | Attorney | Counsel for NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Defendant law firm | Shaw Keller LLP | Law Firm | Representing NuFlow Technologies U.S.A., Inc.Search in Eureka ↗ |
| Presiding judge | Judge N/A | Judge | Delaware District CourtSearch in Eureka ↗ |
Official order — verbatim text
The stipulated dismissal order reveals a carefully negotiated finality structure. Dismissal with prejudice of the asserted claims and corresponding invalidity counterclaims creates mutual claim preclusion on those specific theories — neither party can re-litigate them. The without-prejudice carve-outs for inequitable conduct and non-asserted claim validity, however, preserve NuFlow’s ability to raise those defenses if future litigation arises from the settlement agreement itself. The court’s express retention of jurisdiction under Delaware law — covering contract, tort, and statutory disputes arising from the settlement — is the most commercially significant provision, strongly suggesting the agreement contains ongoing, enforceable obligations between the parties.
US11674628B2, US11802647B2 & US12014458B2 — UV-cure pipe rehabilitation technology
The three asserted patents — US11674628B2 (application US16/639886), US11802647B2 (application US18/326143), and US12014458B2 (application US18/497589) — protect innovations in pipe rehabilitation technology, specifically the installation, curing, and structural restoration of damaged pipelines using liner systems consistent with UV-cure CIPP methodology. The sequential application numbers and relatively recent grant dates suggest a continuing patent family strategy, with Perma-Liner iteratively broadening and refreshing its claim coverage as the technology evolved.
For competitors in the CIPP and trenchless pipe rehabilitation market, this patent family represents a significant IP barrier. The breadth of the assertion — claim 33 of the ‘628 patent, 17 claims of the ‘647 patent, and all 21 claims of the ‘458 patent — indicates comprehensive coverage of the NuCure Cold Cure UV workflow. Companies developing or marketing UV-cure pipe lining systems, particularly those using cold-cure or ambient-cure methodologies, face material FTO exposure across this portfolio. The fact that NuFlow ultimately settled rather than pursuing invalidity to trial suggests the claim language may be difficult to design around.
Should you run an FTO against Perma-Liner’s pipe lining patent family?
Any company developing, manufacturing, or distributing UV-cure or cold-cure cured-in-place pipe lining systems — particularly in the North American market — should treat this patent family as a priority FTO target. Perma-Liner has now demonstrated a clear willingness to assert US11674628B2, US11802647B2, and US12014458B2 against direct commercial rivals. The sequential application structure raises the likelihood of further continuations, meaning the risk perimeter may expand beyond these three patents.
PatSnap Eureka’s FTO Search Agent can map your pipe rehabilitation product specifications against the claim language of the Perma-Liner portfolio — including all continuation applications filed from the same priority chains. Eureka identifies claim element overlap, surfaces prosecution history disclaimers that may narrow scope, and flags related pending applications that could pose future risk. For R&D teams designing UV-cure lining systems, running this analysis before product launch is materially lower cost than defending a Delaware infringement action.
Run a freedom-to-operate analysis on US11802647B2 to assess your product’s exposure
Run FTO in Eureka →Similar patent cases in UV-cure pipe rehabilitation and CIPP technology
Patent disputes involving UV-cure and cured-in-place pipe lining systems in U.S. district courts — cases most structurally comparable to Perma-Liner v. NuFlow.
What this case signals for the pipe rehabilitation IP landscape
Perma-Liner’s three-patent assertion against a direct rival’s flagship product reveals a deliberate enforcement strategy in the CIPP and UV-cure pipe lining sector.
Perma-Liner is building an aggressive patent enforcement posture in CIPP
Asserting three patents simultaneously — covering dozens of claims — against a direct competitor’s core product suggests Perma-Liner is using its IP portfolio as a market access tool, not just a defensive asset. Companies operating in the UV-cure and cured-in-place pipe lining space should audit their product designs against US11674628B2, US11802647B2, and US12014458B2.
Court-retained jurisdiction signals enforceable post-settlement obligations
When Delaware courts retain jurisdiction over a settlement agreement, it typically means the deal contains performance obligations — licensing terms, royalty schedules, or design constraints — that may be enforced on motion. Parties entering similar settlements should treat this clause as a continuing litigation risk, not a clean exit.
Perma-Liner v NuFlow — key questions answered
Perma-Liner Industries, LLC asserted three U.S. patents: US11674628B2, US11802647B2, and US12014458B2. Specifically, it asserted claim 33 of the ‘628 patent, claims 1–10, 12–17, and 19–25 of the ‘647 patent, and claims 1–21 of the ‘458 patent against NuFlow’s NuCure Cold Cure UV product.
The case resolved via private settlement agreement. On August 18, 2025, the court entered a stipulated dismissal under Fed. R. Civ. P. 41(a)(2): Perma-Liner’s infringement claims and NuFlow’s invalidity counterclaims on the asserted claims were dismissed with prejudice; NuFlow’s inequitable conduct claim and non-asserted claim validity challenges were dismissed without prejudice. Each party bears its own costs.
When a Delaware federal court retains jurisdiction over a settlement agreement, it means the court can enforce the deal’s terms on motion without the parties filing a new lawsuit. This typically signals the agreement contains ongoing obligations — such as a license, royalty payments, or product use restrictions — and indicates neither party achieved a complete exit from the commercial relationship.
No. The case settled before any court ruling on validity, infringement, or inequitable conduct. NuFlow’s invalidity counterclaims on the asserted claims were dismissed with prejudice as part of the settlement, meaning those specific theories cannot be re-litigated, but no court adjudicated whether the patents are valid or invalid on the merits.
NuFlow Technologies U.S.A., Inc.’s NuCure Cold Cure UV product was the accused product in this litigation. Perma-Liner alleged that the NuCure Cold Cure UV system infringed the asserted claims across all three patents in suit: US11674628B2, US11802647B2, and US12014458B2.
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