Blackthorn Crown Ltd v. Cirkul Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Blackthorn and Crown LTD. (Cyprus)
  • Defendant: Cirkul, Inc. (Florida)
  • Plaintiff's Counsel: RENNER OTTO (Lead Counsel); Fee & Jeffries, PA. (Local Counsel)
• Case Identification: 8:26-cv-01730, M.D. Fla., 06/12/2026
• Venue Allegations: Venue is alleged in the Middle District of Florida because the Defendant resides, conducts business, and maintains a regular and established place of business within the district.
• Core Dispute: Plaintiff alleges that Defendant's Cirkul SIP® cartridges, which infuse flavor into a base liquid, infringe a patent related to closure arrangements for liquid containers.
• Technical Context: The technology concerns beverage container caps that enable on-demand mixing of an additive (e.g., flavor concentrate) with a base liquid (e.g., water) at the point of consumption.
• Key Procedural History: The complaint alleges that Plaintiff provided Defendant with notice of infringement via a letter dated March 12, 2026, and that Defendant's subsequent sales constitute willful infringement. The prayer for relief contains a single, unsupported reference to a "'919 Patent," which appears to be a clerical error, as all substantive allegations and counts pertain exclusively to the '869 Patent.

Case Timeline

Date	Event
2012-12-14	'869 Patent Priority Date
2019-11-26	'869 Patent Issue Date
2026-03-12	Plaintiff's notice letter sent to Cirkul
2026-06-12	Complaint Filing Date

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

• Patent Identification: U.S. Patent No. 10,486,869, "CLOSURE ARRANGEMENTS FOR LIQUID CONTAINERS, LIQUID CONTAINER ASSEMBLY, AND THE LIKE," issued November 26, 2019 ('869 Patent).

The Invention Explained

• Problem Addressed: The patent describes the logistical and chemical challenges of pre-mixed beverages, which require producing and storing large volumes of liquid for each flavor and often necessitate additives like preservatives and stabilizers to ensure a long shelf life '869 Patent, col. 1:16-28
• The Patented Solution: The invention is a closure arrangement for a liquid container that mixes an additive with a base liquid at the moment of consumption '869 Patent, abstract It features a reservoir holding an additive liquid and a passage for the base liquid. As the user drinks, the additive is drawn from the reservoir into a mixing space within the passage '869 Patent, col. 1:30-39 A central feature is that the additive reservoir is "collapsible," which allows the additive to be dispensed by the user's suction without creating a vacuum, thereby ensuring consistent flow '869 Patent, col. 1:40-44
• Technical Importance: This approach enables on-demand beverage customization, reduces the need for preservatives, and simplifies the supply chain by separating the base liquid from the flavor concentrate until consumption '869 Patent, col. 1:16-28

Key Claims at a Glance

• The complaint asserts that Defendant infringes at least independent claim 1 of the '869 Patent Compl. ¶32 Compl. ¶34
• The essential elements of independent claim 1 include:
  • A closure arrangement comprising a reservoir for an additive liquid.
  • A passage for liquid flow from the container to a user, which includes an inlet, an outlet, and a mixing space.
  • The reservoir is in fluid communication with the mixing space via a junction located between the inlet and outlet.
  • The reservoir is collapsible.
  • The volume of the reservoir decreases as additive flows out "due to a suction force caused by a user-induced flow through the passage."

III. The Accused Instrumentality

Product Identification

• The complaint accuses Cirkul SIP® cartridges and products incorporating them ('869 Products') of infringement Compl. ¶11

Functionality and Market Context

• The complaint alleges that Cirkul SIP® cartridges are designed to be inserted into a bottle opening and function as a closure Compl. ¶17 Compl. ¶19 The cartridges are alleged to contain a reservoir for an additive liquid that is drawn into a mixing space to combine with a base liquid (e.g., water) as a user drinks Compl. ¶20 Compl. ¶24 The complaint alleges the reservoir is collapsible and that its volume decreases due to a suction force created by the user's drinking action Compl. ¶¶28-30 The products are marketed and sold through Defendant's website, Amazon.com, and other retail stores Compl. ¶4

IV. Analysis of Infringement Allegations

The complaint alleges that Cirkul directly infringes at least claim 1 of the '869 Patent Compl. ¶34 While the complaint references a claim chart in Exhibit C, that exhibit is not provided in the filing Compl. ¶31 However, the complaint provides a detailed narrative infringement theory in paragraphs 17 through 30, which are summarized here against the elements of claim 1.

The complaint alleges that the Cirkul SIP® cartridges contain "a reservoir for an additive liquid," corresponding to the first element of claim 1 Compl. ¶20 This reservoir is identified as element "c" in a diagram labeled Exhibit B, which the complaint states is illustrative of the accused product's structure Compl. ¶20 The complaint next alleges the cartridges include a "passage for flow of liquid" with an "inlet" (element "d"), an "outlet" (element "e"), and a "mixing space" (element "f") where the additive and base liquid are received, mapping to the second claim element Compl. ¶¶21-25 A diagram described in the complaint, sourced from a Cirkul patent application publication, is used to identify these alleged infringing components Compl. p. 4, fn. 2

The complaint further alleges that the reservoir is "in fluid communication with, and has a junction with, the mixing space" at a point between the inlet and outlet, satisfying the third element Compl. ¶¶26-27 It then asserts that the reservoir is "collapsible," directly addressing the fourth claim element Compl. ¶¶28-29 Finally, the complaint alleges that the volume of the reservoir decreases as additive flows out "due to a suction force caused by a user-induced flow through the passage," which mirrors the specific causal mechanism required by the final limitation of claim 1 Compl. ¶30

• Identified Points of Contention:
  • Scope Questions: The complaint includes a footnote stating that the diagram used to illustrate infringement (Exhibit B) is from a Cirkul patent application and that "the structures are not exact matches to the structure of Cirkul's SIP® cartridges" Compl. p. 4, fn. 2 This statement may create a point of contention regarding whether the actual accused product contains the structures as alleged, or if there are material differences that take it outside the scope of the claims.
  • Technical Questions: A key technical question will be whether the accused product's reservoir empties via the specific mechanism recited in the claim: "due to a suction force caused by a user-induced flow through the passage" Compl. ¶30 The defense may argue that the reservoir collapses due to a different physical principle (e.g., ambient air pressure equalization, mechanical action) or that the user's suction is not the direct and sole cause as required by the claim language.

V. Key Claim Terms for Construction

• The Term: "collapsible"

  • Context and Importance: This term is central to the invention's mechanism. Its interpretation will determine what types of reservoirs are covered by the claim. Practitioners may focus on this term because its scope-whether it is limited to a passively collapsing bag or broadly includes any structure that reduces volume-will be critical to the infringement analysis.
  • Evidence for a Broader Interpretation: The specification suggests the reservoir could be a "bag or a pouch" and may be formed of either "resiliently deformable material or of a non-resiliently deformable material," supporting a broad definition that is not tied to a specific material property '869 Patent, col. 2:8-11
  • Evidence for a Narrower Interpretation: The patent also discloses an alternative embodiment as "a syringe with a plunger" '869 Patent, col. 2:14-16 but describes the primary embodiment as being "flexible, thin walled" '869 Patent, col. 12:56-57 A party could argue that in the context of the asserted claim, which relies on a passive "suction force," the term "collapsible" should be construed to mean a non-mechanical, bag-like structure, as distinct from a mechanically-driven syringe.

• The Term: "suction force caused by a user-induced flow"

  • Context and Importance: This phrase recites the specific cause for the effect of the additive being dispensed and the reservoir collapsing. Proving that the accused device operates by this exact mechanism is essential for a finding of literal infringement.
  • Evidence for a Broader Interpretation: A plaintiff may argue this language encompasses any negative pressure differential created in the flow path by a user drawing liquid, which results in additive being drawn from the reservoir. The patent describes this generally as the result of a user applying "a suction force as indicated by arrow A" '869 Patent, col. 12:28-29
  • Evidence for a Narrower Interpretation: A defendant may argue that this requires a specific fluid dynamic principle, and that the "suction force" must be the sole or predominant cause of the additive flow and reservoir collapse. The patent's explicit causal language, "decreases as a result of... due to a suction force," suggests a direct chain of causation that may be challenged if other forces (like air pressure or gravity) are found to play a significant role in the accused device '869 Patent, col. 22:30-34

VI. Other Allegations

• Indirect Infringement: The complaint does not plead a separate count for indirect infringement. Its sole count is for direct infringement under 35 U.S.C. § 271(a) Compl. ¶34
• Willful Infringement: The complaint alleges that Cirkul's infringement has been and continues to be willful Compl. ¶36 The basis for this allegation is Defendant's alleged continued infringement after receiving a notice letter on March 12, 2026, which allegedly provided Cirkul with knowledge of the '869 Patent and its infringement Compl. ¶¶13-15

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

• A core issue will be one of causal mechanism: does the accused Cirkul SIP® cartridge operate via the specific fluid dynamics required by Claim 1? The case will likely require expert evidence to determine if the reservoir's volume decreases "due to a suction force caused by a user-induced flow," or if another mechanism is at play.
• A second key question will be one of structural mapping: in light of the complaint's own hedge that its diagrams are "not exact matches" Compl. p. 4, fn. 2, the court will need to determine whether the actual physical structure of the accused cartridge meets the claim limitations of a "reservoir," "passage," and "junction" as defined by the patent, either literally or through the doctrine of equivalents.
• Finally, the case may turn on a question of definitional scope: how broadly will the court construe the term "collapsible"? A narrow construction limited to a specific type of passive, bag-like structure could be dispositive if the accused product achieves volume reduction through a different design.