Straight Line v. Insultherm

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Straight Line Industrial Services, Inc. (Texas)
  • Defendant: Insultherm Inc. (Texas)
  • Plaintiff’s Counsel: Edmonds & Nolte, P.C.
• Case Identification: 4:25-cv-05175, S.D. Tex., 02/24/2026
• Venue Allegations: Venue is alleged to be proper in the Southern District of Texas because both parties maintain their principal places of business within the district, and a substantial part of the events giving rise to the claims, including the Defendant's alleged patent enforcement threats, occurred there.
• Core Dispute: Plaintiff seeks a declaratory judgment that its industrial insulation panels do not infringe Defendant’s patents related to insulated coke drum systems, and further alleges trade secret misappropriation, unfair competition, and antitrust violations.
• Technical Context: The technology at issue is external thermal insulation for petroleum refinery coke drums, which operate at extreme temperatures and require specialized systems to accommodate significant thermal expansion and contraction without compromising insulation integrity.
• Key Procedural History: The complaint alleges that the dispute arose after Plaintiff submitted a confidential bid to a customer, which Defendant then allegedly improperly acquired. The complaint states Defendant immediately sent Plaintiff a cease-and-desist letter alleging patent infringement, leading Plaintiff to file this action seeking a judgment of non-infringement and asserting claims based on Defendant's alleged conduct.

Case Timeline

Date	Event
c. 2004	Plaintiff begins selling its insulation panels
2016-04-26	Priority Date for U.S. Patent Nos. 10,323,190 & 11,034,890
2019-06-18	U.S. Patent No. 10,323,190 Issues
2021-06-15	U.S. Patent No. 11,034,890 Issues
2025-10-20	Plaintiff submits confidential bid to Marathon
2025-10-21	Defendant sends cease-and-desist letter to Plaintiff
2026-02-24	Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,323,190 - "Insulated Coke Drum, Insulation System Therefore, and Method of Installing Same," issued June 18, 2019 (’190 Patent)

The Invention Explained

• Problem Addressed: The patent’s background section describes the technical challenge of insulating refinery coke drums, which undergo significant thermal expansion and contraction during operation ([’190](https://ai-lab.exparte.com/patent/10323190) Patent, col. 2:17-21). This thermal movement can damage conventional insulation systems, leading to reduced efficiency and potential safety issues (’190 Patent, col. 1:53-60).
• The Patented Solution: The invention is a complete insulation system for a coke drum that is designed to "float" independently of the drum's surface (’190 Patent, col. 2:16-21). This is achieved using an "insulation support system" comprising "weldments" or "clips" attached to the drum's exterior (’190 Patent, col. 2:35-43). These weldments support, but are not rigidly attached to, a series of insulation support rings. Insulation panels are then secured to these rings, creating a gap between the panels and the drum wall that accommodates thermal movement (’190 Patent, Fig. 5). The system is held together by external tensioned cables that are routed through eyelets in the standing seams between adjacent panels (’190 Patent, col. 2:44-54).
• Technical Importance: This design approach provides a durable, weather-proof, and maintenance-free insulation system that is structurally decoupled from the vessel wall, allowing it to withstand the harsh thermal cycling inherent in coke drum operations.

Key Claims at a Glance

The complaint identifies claims 1, 2, 4, 7, 9, 14, 16, and 20 of the ’190 patent as having been asserted (Compl. ¶16). Claim 1 is the sole independent claim.

• Independent Claim 1: An insulated coke drum system comprising:
  • (a) a coke drum having an external diameter, an exterior surface, and a longitudinal axis; and
  • (b) an insulation system installed on the coke drum exterior surface, where the system itself includes:
    • i) an insulation support system with spaced-apart weldments welded to the coke drum and insulation support rings supported by, but not attached to, the weldments;
    • ii) a plurality of insulation panels secured to the support rings, positioned with single-folded standing seams; and
    • iii) a plurality of external tensioned insulation securing cables routed through eyelets in each standing seam.

U.S. Patent No. 11,034,890 - "Insulated Vessels, Insulation Systems Therefore, and Methods of Installing Same," issued June 15, 2021 (’890 Patent)

The Invention Explained

• Problem Addressed: As a divisional of the application leading to the ’190 patent, the ’890 Patent addresses the same technical problem: the need for a robust method of insulating industrial vessels like coke drums that are subject to significant thermal movement (’890 Patent, col. 2:5-11).
• The Patented Solution: The patent claims methods of installing the type of "floating" insulation system described in the ’190 patent. The claimed method involves attaching a support structure (like a "floating ring system" or "cage system") to the vessel, attaching insulation panels to that structure, and securing the entire assembly using external tensioned cables routed through eyelets in the panels' standing seams (’890 Patent, col. 19:1-20:20).
• Technical Importance: The method provides a way to implement the structurally decoupled insulation system, aiming to ensure its proper function and longevity in a demanding industrial environment.

Key Claims at a Glance

The complaint seeks a declaratory judgment of non-infringement for the entire patent (Compl. ¶71). Claim 1 and Claim 3 are independent method claims.

• Independent Claim 1: A method of insulating a vessel comprising:
  • (a) attaching an insulation support structure (floating ring or cage system) to the vessel's external surface;
  • (b) attaching a plurality of insulation panels to the support structure; and
  • (c) securing the panels by forming standing seams, forming an eyelet in a lower section of each seam, and tensioning external securing cables through the eyelets.

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are Plaintiff's "proposed insulated panels" offered in a confidential bid to Marathon Oil/Gas, as well as "similar offerings" (Compl. ¶1; Compl. ¶69).

Functionality and Market Context

The complaint describes the products as "external thermal insulated or (insulation) panels" for use in industrial applications like refinery coke drum insulation (Compl. ¶1; Compl. ¶3). Plaintiff alleges that it "only makes and sells insulation panels" and does not supply the other components recited in Defendant's patent claims, such as "coker drums, weldments and/or specialized support rings" (Compl. ¶19). The complaint positions Plaintiff and Defendant as "direct competitors" in this market (Compl. ¶10).

IV. Analysis of Infringement Allegations

The complaint does not contain a claim chart or specific element-by-element infringement allegations from the Defendant; rather, it states that Defendant's notice letter "did not provide a claim chart nor include any technical basis supporting its allegation" (Compl. ¶16). The analysis is therefore based on the non-infringement theory articulated by the Plaintiff in its complaint for declaratory judgment.

Plaintiff’s central theory of non-infringement is that it cannot be liable for direct infringement because it only sells one component—insulation panels—of the multi-component systems claimed in the patents-in-suit (Compl. ¶19). The asserted independent claims of both the ’190 and ’890 patents recite combinations of elements, including the coke drum itself, weldments attached to the drum, support rings, and tensioned cables, in addition to the insulation panels. Plaintiff alleges it does not make, use, or sell the complete claimed "insulated coke drum" system or perform all steps of the claimed installation method (Compl. ¶19; Compl. ¶71).

• Identified Points of Contention:
  • Direct Infringement (System vs. Component): A primary legal question is whether the sale of insulation panels alone can constitute direct infringement of claims directed to a complete system (the "insulated coke drum") or a multi-step method. The analysis will likely require determining whether Plaintiff makes, uses, offers to sell, or sells the entire claimed invention.
  • Indirect Infringement: While not explicitly pleaded by the Defendant, any viable infringement claim would likely need to be based on a theory of indirect infringement (inducement or contributory infringement). This raises the question of whether Plaintiff's actions could be seen as encouraging or enabling its customers to assemble an infringing system.
  • Staple Article Doctrine: The complaint raises a potential defense to contributory infringement by alleging that Plaintiff has engaged in "20+ years of open manufacturing and supply of the same product" (Compl. ¶44), which "establish[es] prior art to the asserted patents" (Compl. ¶55). This suggests Plaintiff may argue its panels are a staple article of commerce with substantial non-infringing uses, particularly if they were sold long before the patents issued.

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

• The Term: "An insulated coke drum comprising" (’190 Patent, claim 1 preamble)

  • Context and Importance: This preamble language defines the scope of the claimed invention as an entire system, not just a component part. The entire dispute over direct infringement hinges on this scope. Practitioners may focus on this term because Plaintiff's non-infringement defense rests on its assertion that it only sells a component (panels) and not the complete claimed system.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A party arguing for broader scope might contend that the novel features reside in the components, but this is typically a difficult argument for system claims where the combination is the invention.
    • Evidence for a Narrower Interpretation: The patent specification consistently frames the invention as the complete assembly. The "Summary" section explicitly states, "A first aspect of the disclosure is an insulated coke drum comprising: (a) a coke drum...; (b) an insulation system installed on the coke drum..." (’190 Patent, col. 2:28-33). This supports a construction where the claim is limited to the entire finished product.

• The Term: "weldments welded to the coke drum exterior surface" (’190 Patent, claim 1(b)(i))

  • Context and Importance: Plaintiff specifically alleges that it does not provide "weldments" (Compl. ¶19). The definition of this term is therefore critical to determining what is required by the claim and whether the panels sold by Plaintiff are uniquely designed for an infringing system or have other uses.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent notes that weldments are "sometimes referred to as support clips" (’190 Patent, col. 6:28-29), but provides little basis for a definition beyond a physical attachment welded to the drum.
    • Evidence for a Narrower Interpretation: The specification provides specific examples, stating the weldments are "preferably vertical, rectangular CS plates, or ‘clips’" (’190 Patent, col. 2:35-37). Figures 2 and 3 provide detailed illustrations of these components (e.g., item 18), supporting a narrow construction tied to these specific structural forms.

VI. Other Allegations

• Indirect Infringement: The complaint does not directly address allegations of indirect infringement. However, the facts pleaded raise issues central to such a claim. Plaintiff's assertion that it has sold "the same product" for over 20 years suggests the panels are staple articles of commerce suitable for substantial non-infringing uses, which would be a defense to a claim of contributory infringement (Compl. ¶44; Compl. ¶55).
• Willful Infringement: As this is a declaratory judgment action, willfulness is not alleged against the Plaintiff. However, the complaint establishes that Defendant had pre-suit knowledge of the allegedly infringing activity via its cease-and-desist letter dated October 21, 2025 (Compl. ¶16). The complaint also contains allegations that Defendant's infringement threats were "objectively baseless and in bad faith," which relates to the state of mind for willfulness and may be relevant to Plaintiff's claims for unfair competition or a potential fee award (Compl. ¶17).

VII. Analyst’s Conclusion: Key Questions for the Case

• System vs. Component Liability: A core legal issue will be whether the sale of only insulation panels can create liability for infringement of patent claims directed to a complete "insulated coke drum" system and methods of its installation. The case will likely turn from a direct infringement analysis to one of indirect infringement.
• Patent Validity in View of Prior Sales: A central evidentiary question will be whether Plaintiff's alleged history of selling the same or similar insulation panels since 2004—more than a decade before the patents' 2016 priority date—constitutes invalidating prior art, as the complaint suggests (Compl. ¶55).
• The Staple Article Defense: Should the patents be deemed valid, a key factual dispute may be whether Plaintiff’s insulation panels are a "staple article or commodity of commerce suitable for substantial non-infringing use." Plaintiff’s long sales history will be central evidence in this analysis, potentially shielding it from liability for contributory infringement.