Xiamen Huangyudu Cosmetics Co Ltd v. Interlink Products Intl Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Xiamen Huangyudu Cosmetics Co., Ltd. d/b/a RAZIME LLC (People's Republic of China)
  • Defendant: Interlink Products International, Inc. (New Jersey) and Eli Zhadanov (New York)
  • Plaintiff's Counsel: Glacier Law LLP
• Case Identification: 2:25-cv-02734, W.D. Wash., 03/16/2026
• Venue Allegations: Plaintiff alleges venue is proper in the Western District of Washington because Defendants directed patent enforcement activities into the district by initiating an Amazon Patent Evaluation Express (APEX) proceeding and sending related communications to Amazon personnel located in in Seattle, which constitutes a substantial part of the events giving rise to the action.
• Core Dispute: Plaintiff seeks a declaratory judgment that its rain shower head product does not infringe two of Defendants' patents related to multi-function showerheads and that the patents are invalid.
• Technical Context: The technology concerns showerheads with multiple, independently selectable sets of nozzles designed to provide different water flow patterns, such as a standard shower spray, a fan-shaped spray for cleaning, and a high-pressure jet stream.
• Key Procedural History: Defendants previously accused Plaintiff's products of infringing the '435 Patent through Amazon's APEX process, threatening removal of the product listings. Defendants have also asserted the '850 Patent against similar products in separate litigation in the Eastern District of New York, creating the basis for the present declaratory judgment action.

Case Timeline

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

U.S. Patent No. 12,485,435 - "Showerhead Having Selector For Directing Water Flow In Independent Directions"

• Issued: December 2, 2025

The Invention Explained

• Problem Addressed: The patent's background section notes that conventional showerheads, designed primarily for showering, may provide water pressure and spray patterns that are undesirable or ineffective for cleaning shower areas like tiled walls and tubs ʼ435 Patent, col. 1:19-27
• The Patented Solution: The invention is a multi-function showerhead that includes a standard set of nozzles on its faceplate for showering, as well as separate nozzles located elsewhere on the showerhead head (e.g., on a side opposite the faceplate) designed for cleaning tasks ʼ435 Patent, abstract These separate nozzles can create different spray types, such as a fan-shaped spray or a high-pressure jet stream, and a "flow selector" mechanism allows the user to divert water between the different nozzle groups ʼ435 Patent, col. 4:11-40
• Technical Importance: This design purports to combine a standard showering device with a specialized high-pressure cleaning tool in a single unit, eliminating the need for separate cleaning implements.

Key Claims at a Glance

• The complaint asserts non-infringement of the patent's claims, including independent claim 1 Compl. ¶27 The '435 Patent is noted to have two independent claims Compl. ¶18
• Independent Claim 1 of the '435 Patent includes these essential elements:
  • A head portion and a handle.
  • A plurality of first nozzles configured to direct water in a first direction.
  • At least one second nozzle disposed in the head portion to direct water in a second direction.
  • At least one third nozzle adjacent to the second nozzle to direct water in a third direction.
  • A flow selector moveable between a first position (directing water to the first nozzles), a second position (directing water to the second nozzle), and a third position (directing water to the third nozzle).
  • The second and third directions are substantially the same and transverse to the first direction.
  • The second nozzle creates a first type of water flow (e.g., fan-shaped spray) and the third nozzle creates a different, second type (e.g., jet stream).
• The complaint does not explicitly reserve the right to assert dependent claims but seeks a declaration of non-infringement for "any claim of the '435 Patent" Compl. ¶27

U.S. Patent No. 11,992,850 - "Showerhead Having Selector For Directing Water Flow In Independent Directions"

• Issued: May 28, 2024

The Invention Explained

• Problem Addressed: The '850 Patent, which is the parent of the '435 Patent, addresses the same technical problem: the unsuitability of conventional showerhead spray patterns and pressures for cleaning tasks within a shower enclosure '850 Patent, col. 1:6-20
• The Patented Solution: The patented solution is a showerhead with distinct sets of nozzles for showering and cleaning, where a movable "flow director" internally routes water to one of several "plenums" ʼ850 Patent, abstract Each plenum is a chamber that feeds a specific nozzle or group of nozzles, allowing the user to select between the standard shower spray, a fan-shaped cleaning spray, or a high-pressure jet stream '850 Patent, col. 1:36-49 '850 Patent, col. 4:32-37
• Technical Importance: The invention provides a mechanical framework using separate plenums and a flow director to achieve distinct, selectable water outputs from a single showerhead unit.

Key Claims at a Glance

• The complaint asserts non-infringement of claims 1, 9, and 14, all of which are independent claims Compl. ¶22 Compl. ¶51
• Independent Claim 1 of the '850 Patent includes these essential elements:
  • A head portion, handle, and faceplate with a plurality of first nozzles.
  • A second nozzle and a third nozzle separate from the faceplate.
  • A first plenum fluidly coupled to the first nozzles.
  • A second plenum fluidly coupled to the second nozzle.
  • A third plenum fluidly coupled to the third nozzle.
  • A flow director moveable between positions to selectively couple a main water channel to the first, second, or third plenum.
• Independent Claims 9 and 14 recite similar structures, each requiring a first, second, and third plenum coupled to different nozzle sets and a moveable flow director to select between them '850 Patent, col. 9:1-22 '850 Patent, col. 10:1-45
• The complaint seeks a declaration of non-infringement for "any claim of the '850 Patent" Compl. ¶50

III. The Accused Instrumentality

Product Identification

• Plaintiff's "rain shower head" sold on Amazon.com under various ASINs, including B0F9L5YV2G and B0F7HL3R71 Compl. ¶10 Compl. ¶11 Compl. ¶24

Functionality and Market Context

• The Accused Product is alleged to employ a "materially different flow-selection structure and operating scheme" than what is claimed in the patents Compl. ¶28
• Its functionality is described as using a "rotatable disc/faceplate mechanism" to operate in "multiple discrete positions" Compl. ¶28 This mechanism routes water through different internal passageways to "side outlets and to selected subsets of faceplate nozzles" Compl. ¶28
• The product allegedly includes an "additional 'off' position" where no water is discharged, a feature Plaintiff contends is not recited in the patents' claims Compl. ¶28
• The complaint states that the Amazon marketplace is Plaintiff's "primary sales channel in the United States," and Defendants' enforcement actions threaten to cut off access to this channel Compl. ¶15

IV. Analysis of Infringement Allegations

No probative visual evidence provided in complaint.

This is a declaratory judgment action where the Plaintiff alleges non-infringement. The following tables summarize the Plaintiff's non-infringement contentions.

'435 Patent Infringement Allegations

'850 Patent Infringement Allegations

Identified Points of Contention

• Scope Questions: A primary question for the '435 Patent will be whether the term "flow selector moveable between" the recited positions can be construed to read on the accused "rotatable disc/faceplate mechanism." For the '850 Patent, the dispute centers on whether any internal water-routing structures in the accused product meet the claim-required definition of a "plenum."
• Technical Questions: What evidence does the complaint provide that the accused product's internal structure lacks any chambers that could be characterized as "plenums"? Further, does the accused product's mechanism of routing water to "subsets of faceplate nozzles" differ fundamentally from the claimed function of directing flow to the "plurality of first nozzles" as a whole?

V. Key Claim Terms for Construction

The Term: "plenum" ('850 Patent, claims 1, 9, 14)

• Context and Importance: This term is the sole basis for the non-infringement allegations against the '850 Patent Compl. ¶51 The Plaintiff's assertion that its product "has no plenum" makes the construction of this term dispositive for those claims.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claims themselves provide a functional definition, describing a plenum as a structure "disposed within the head portion and fluidly coupled" to a set of nozzles '850 Patent, col. 7:4-12 This broad functional language could support an argument that any internal chamber directing flow to a nozzle group is a "plenum."
  • Evidence for a Narrower Interpretation: The summary of the invention and detailed description consistently describe three distinct plenums (first, second, and third) that are each fed selectively by a "flow director" '850 Patent, col. 1:36-49 '850 Patent, col. 4:56-59 A defendant might argue this structure implies separate, discrete chambers, and that a device with a different internal routing architecture (e.g., a rotating disc that opens and closes ports without distinct intermediate chambers) would not meet this narrower definition.

The Term: "flow selector moveable between a first position... a second position, and a third position" ('435 Patent, claim 1)

• Context and Importance: Plaintiff alleges its "rotatable disc/faceplate mechanism" is "materially different" Compl. ¶28 The case may turn on whether the accused mechanism, which allegedly has "multiple discrete positions" including an "off" position, falls within the scope of the claimed three-position selector.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim language recites movement "between" three functional positions without specifying the mechanism (e.g., linear switch, rotary dial). This could support an argument that any mechanism achieving the three claimed functional outputs, regardless of its specific mechanical nature or additional positions, meets the limitation.
  • Evidence for a Narrower Interpretation: The specification depicts the flow selector as a distinct switch element (116) that moves a flow director (208) to align with different plenums '435 Patent, Figs. 2A-4B '435 Patent, col. 4:31-40 A defendant could argue that this disclosure limits the term "flow selector" to a similar switching mechanism, as opposed to an integrated rotating faceplate.

VI. Other Allegations

• Indirect Infringement: The complaint preemptively denies claims of indirect infringement. It alleges it has not encouraged or intended for customers to practice the claimed invention and that the Accused Product is a "staple article of commerce suitable for substantial non-infringing uses" Compl. ¶30 Compl. ¶52

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

• A core issue will be one of claim construction: does the term "plenum" as used in the '850 Patent require three physically separate and discrete chambers, or can it be construed more broadly to cover any internal structure that routes water to a specified nozzle group, potentially reading on the accused product's architecture?
• A second key issue will be one of structural and functional scope: for the '435 Patent, does the accused "rotatable disc/faceplate mechanism," which includes additional operational positions like "off," fall within the literal scope of a "flow selector moveable between" the three specified functional positions, or does its different mechanical implementation and expanded functionality place it outside the claim?
• An ultimate evidentiary question will be one of technical comparison: assuming the court adopts constructions for "plenum" and "flow selector," the factual dispute will focus on whether the internal mechanics and water flow paths of the Accused Product meet the specific structural and functional requirements of those construed terms.