3B Medical Mfg LLC v. Rhythm Healthcare LLC

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: 3B Medical Mfg, LLC (Florida)
  • Defendant: Rhythm Healthcare, LLC (Delaware)
  • Plaintiff's Counsel: Hahn Loeser & Parks LLP; Carlson, Gaskey & Olds, P.C.
• Case Identification: 8:25-cv-02989, M.D. Fla., 10/31/2025
• Venue Allegations: Venue is alleged to be proper as Defendant has a principal place of business in the district and has committed acts giving rise to the infringement claims within the district.
• Core Dispute: Plaintiff, an exclusive licensee, alleges that Defendant's portable oxygen concentrator and its associated removable sieve beds infringe a patent related to the design of adsorbent cartridges used in such devices.
• Technical Context: The technology relates to portable oxygen concentrators (POCs), which are medical devices that separate oxygen from ambient air to deliver concentrated oxygen to patients, typically those with respiratory conditions.
• Key Procedural History: Plaintiff 3B Medical Manufacturing, LLC, became the exclusive licensee of the patent-in-suit from the original inventor, VBox, Inc., through a March 16, 2018 agreement that grants the right to sue for infringement. The complaint asserts that Plaintiff provided Defendant with actual notice of the alleged infringement via correspondence on June 25, 2025.

Case Timeline

Date	Event
2005-02-09	'005 Patent Priority Date
2009-10-20	'005 Patent Issue Date
2018-03-16	Intellectual Property License Agreement between VBox, Inc. and 3B Manufacturing
2025-06-25	Plaintiff sends correspondence to Defendant alleging infringement
2025-10-31	Complaint Filing Date

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

• Patent Identification: U.S. Patent No. 7,604,005 ("Adsorbent Cartridge for Oxygen Concentrator"), issued October 20, 2009 (the "'005 Patent").

The Invention Explained

• Problem Addressed: The patent's background describes the limitations of existing oxygen therapy systems for ambulatory patients, such as heavy compressed gas cylinders with limited supply and liquid oxygen systems prone to evaporation and requiring frequent refills '005 Patent, col. 2:5-50 The patent identifies a need for an improved portable oxygen concentrator that is lightweight and efficient for mobile users '005 Patent, col. 2:62-65
• The Patented Solution: The '005 Patent discloses a removable gas separation cartridge for a portable oxygen concentrator. This cartridge contains multiple columns filled with an adsorbent material (e.g., zeolite) that preferentially adsorbs nitrogen from ambient air '005 Patent, abstract Using a vacuum swing absorption (VSA) process, the system separates oxygen, which is then delivered to the patient '005 Patent, col. 3:9-12 The invention's key feature is the modular and easily replaceable nature of the adsorbent cartridge, as illustrated in the patent's figures '005 Patent, Fig. 7
• Technical Importance: This modular design allows for simple replacement of the adsorbent material, which degrades over time, thereby simplifying maintenance and improving the usability of portable oxygen concentrators for patients '005 Patent, col. 12:28-36

Key Claims at a Glance

• The complaint asserts independent claim 10 of the '005 Patent Compl. ¶26
• The essential elements of Claim 10 are:
  • A removable cartridge for a portable oxygen concentrator, the cartridge comprising:
  • an outer casing;
  • a plurality of gas separation columns within the outer casing, each gas separation column containing an adsorbent material that preferentially adsorbs nitrogen, a first end, and a second end;
  • a plurality of inlet ports in the outer casing, each inlet port connect to the first end of one of the columns; and
  • a plurality of outlet ports in the outer casing, each outlet port connected to the second end of one of the columns.

III. The Accused Instrumentality

Product Identification

• The accused instrumentalities are the Rhythm Healthcare P2 Portable Oxygen Concentrator and its corresponding Sieve Beds Compl. ¶12

Functionality and Market Context

• The complaint alleges that the accused products are portable oxygen concentrators that practice the claimed inventions Compl. ¶12 The "Sieve Bed" is identified as a removable component that corresponds to the claimed "removable cartridge" Compl. ¶¶12-13
• The complaint provides an image of the P2 Portable Oxygen Concentrator unit (Compl. ¶12, Ex. 1) and a separate image of the corresponding Sieve Bed component (Compl. ¶13, Ex. 2). The functionality is further detailed in an infringement claim chart, which shows the Sieve Bed as a self-contained unit with ports for gas ingress and egress Compl. Ex. 4
• The complaint alleges that Defendant is in the business of manufacturing and selling these products but does not provide further detail on their market positioning Compl. ¶12

IV. Analysis of Infringement Allegations

'005 Patent Infringement Allegations

Claim Element (from Independent Claim 10)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A removable cartridge for a portable oxygen concentrator, the cartridge comprising:	The P2 Portable Oxygen Concentrator includes a removable cartridge, identified as the Sieve Bed.	¶27	col. 3:5-12
an outer casing;	The Sieve Bed includes an outer casing, identified as its external housing. The complaint's claim chart shows an annotated image labeling the metallic body of the Sieve Bed as the "Outer casing" Compl. Ex. 4, p. 3	¶27	col. 18:37-39
a plurality of gas separation columns within the outer casing, each gas separation column containing an adsorbent material that preferentially adsorbs nitrogen, a first end, and a second end;	The Sieve Bed allegedly contains a plurality of gas separation columns within its casing, with each column containing adsorbent material that preferentially adsorbs nitrogen. The complaint's chart annotates the internal structure and identifies a "First end" and "Second end" Compl. Ex. 4, p. 3	¶27	col. 5:20-22
a plurality of inlet ports in the outer casing, each inlet port connect to the first end of one of the columns;	The Sieve Bed is alleged to have a plurality of inlet ports in its outer casing that connect to the first end of the gas separation columns. The claim chart shows arrows pointing from the ports to the columns Compl. Ex. 4, p. 4	¶27	col. 18:37-41
and a plurality of outlet ports in the outer casing, each outlet port connected to the second end of one of the columns.	The Sieve Bed is alleged to have a plurality of outlet ports in its outer casing that connect to the second end of the gas separation columns, as depicted with arrows in the complaint's claim chart Compl. Ex. 4, p. 4	¶27	col. 18:37-41

Identified Points of Contention

• Scope Questions: The claim requires "a plurality of gas separation columns within the outer casing." The complaint's evidence depicts the accused Sieve Bed as an integrated unit where the external housing may also form the walls of the columns Compl. Ex. 4, p. 3 This raises the question of whether a structure where the columns and casing are integrated, rather than the columns being separate components placed "within" a distinct casing, meets this limitation as understood in the context of the patent.
• Technical Questions: Claim 10 recites that "each inlet port connect to the first end of one of the columns." This language may suggest a one-to-one connection. A potential point of dispute is the precise nature of the fluidic connection in the accused Sieve Bed. The analysis may explore whether the accused device uses a manifold or another connection architecture that a court could find does not meet the "connect to one of the columns" limitation.

V. Key Claim Terms for Construction

• The Term: "outer casing"

• Context and Importance: The relationship between the "outer casing," the "gas separation columns," and the "ports" is central to Claim 10. The claim requires the columns to be "within" the casing and the ports to be "in" the casing. Practitioners may focus on this term because the accused product appears to be an integrated aluminum extrusion where the column walls and the outer housing are a single piece.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The patent uses the term "housing" in the claims to describe the structure "for containing the... adsorbent columns" '005 Patent, col. 26:34-36 This could support an interpretation where "casing" broadly refers to any structure that encloses or defines the columns.
  • Evidence for a Narrower Interpretation: The exploded view in Figure 16 depicts the "casing 230" as a distinct component into which the separate "adsorbent columns 130a-130c" are inserted '005 Patent, Fig. 16 This could support a narrower construction requiring the "outer casing" to be a structurally separate element from the "gas separation columns."

• The Term: "connect to"

• Context and Importance: This term defines the required relationship between the ports and the columns. The manner of this connection (e.g., direct abutment, via a manifold, through tubing) will be critical for the infringement analysis.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification describes connections between components using intermediate tubing, such as "inlet ports 132a-132c of adsorbent columns 130a-130c connect to valve 140 through inlet lines 164a-164c" '005 Patent, col. 5:28-30 This suggests "connect to" does not strictly require direct physical contact and can encompass fluidic communication through other components.
  • Evidence for a Narrower Interpretation: The phrasing "each inlet port connect to the first end of one of the columns" could be argued to imply a direct, one-to-one fluidic pathway, distinguishing it from a common manifold that feeds multiple columns from a single plenum. The complaint's own claim chart uses arrows to depict a direct path from each port opening to a column end, suggesting this interpretation may be part of its infringement theory Compl. Ex. 4, p. 4

VI. Other Allegations

Indirect Infringement

• The complaint alleges induced infringement under 35 U.S.C. § 271(b) Compl. ¶¶35-53 The allegations are based on Defendant providing "instructions and marketing materials," including videos and user manuals, that allegedly instruct customers and end-users on how to install, assemble, and use the P2 Portable Oxygen Concentrator and Sieve Beds in an infringing manner Compl. ¶37 Compl. ¶39 The complaint alleges that Defendant possessed the specific intent for its customers to infringe Compl. ¶38

Willful Infringement

• The complaint alleges that Defendant's infringement has been willful and deliberate Compl. ¶33 Compl. ¶52 This allegation is based on Defendant's alleged knowledge of the '005 Patent, at least as of the June 25, 2025 notice letter Compl. ¶28, and its alleged continued infringement despite an "objectively high likelihood" of infringement Compl. ¶32

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

• A core issue will be one of claim construction: can the term "outer casing", as described in a patent that depicts it as a distinct housing, be construed to read on the accused product's integrated structure where the external housing and internal column walls appear to be a single, monolithic component?
• A key evidentiary question will be one of structural infringement: does the accused Sieve Bed's architecture meet the claim requirement that "each" port "connect to... one of the columns," or does it employ a manifold or other fluidic distribution system that falls outside the scope of this limitation?
• Should infringement be established, a central question for damages will be willfulness: did Defendant's conduct, particularly after receiving notice of its alleged infringement on June 25, 2025, rise to the level of egregious behavior that would justify an award of enhanced damages?