Immersion Systems LLC v. Midas Green Technologies LLC

1. Case Identification

• Case #: IPR2021-01176
• Patent #: 10,405,457
• Filed: June 23, 2021
• Petitioner(s): Immersion Systems LLC
• Patent Owner(s): Midas Green Technologies, LLC
• Challenged Claims: 1, 5, 6, 10, 11, and 14

2. Patent Overview

• Title: Appliance Immersion Cooling System
• Brief Description: The ’457 patent relates to systems for cooling electronic appliances by immersing them in a dielectric fluid within a tank. The invention is directed to a specific configuration featuring a weir integrated into a tank wall and a fluid recovery reservoir positioned vertically beneath the weir to manage fluid circulation and heat removal efficiently.

3. Grounds for Unpatentability

Ground 1: Obviousness over Best in view of Krajewski and/or Cray - Claims 1, 5, 6, 10, 11, and 14 are obvious over Best in view of Krajewski and/or Cray.

• Prior Art Relied Upon: Best (Patent 10,123,463), Krajewski (Patent 5,167,511), and Cray (Patent 4,590,538).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Best, as the primary reference, discloses most limitations of independent claim 1, including an immersion cooling tank, vertically arranged appliance slots, a primary circulation facility with a plenum, a secondary heat-extraction facility, and a control facility. Petitioner contended that the key limitation added during prosecution to secure allowance—a "dielectric fluid recovery reservoir positioned vertically beneath the overflow lip of the weir"—is taught by the secondary references. Krajewski allegedly discloses this by teaching that fluid flows over the top of an inner wall (a weir) and is returned down between walls to a reservoir. Similarly, Cray allegedly teaches fluid flowing over the tops of stand-pipes (a weir) and collecting at the bottom for recirculation, which functions as a reservoir.
  • Motivation to Combine: A POSITA would combine these references as they are all directed to the same field of immersion cooling for electronics and address similar design challenges. Petitioner asserted that combining the known weir/reservoir arrangements from Krajewski or Cray with Best's system was a predictable solution to known problems of floor space and fluid management. The combination simply applies known techniques to a known system to achieve predictable results.
  • Expectation of Success: A POSITA would have a strong expectation of success because integrating a reservoir vertically beneath a weir is a conventional and logical design choice that obviously exploits gravity for fluid collection, requiring no undue experimentation.

Ground 2: Obviousness over Best in view of Oktay - Claims 1, 5, 6, 10, 11, and 14 are obvious over Best in light of Oktay.

• Prior Art Relied Upon: Best (Patent 10,123,463) and Oktay (Patent 3,406,244).

• Core Argument for this Ground:

  • Prior Art Mapping: Similar to Ground 1, Petitioner relied on Best to teach the foundational elements of the claimed immersion cooling system. The secondary reference, Oktay, was cited to teach the specific weir and reservoir combination that Best allegedly lacks. Petitioner argued that Oktay discloses a weir in the form of "a plurality of overflow orifices" and teaches that "a pool of liquid 93 collects, above the bottom wall of enclosure 85," which functions as a fluid recovery reservoir. This pool collects fluid that overflows the weir, placing the reservoir vertically beneath it as required by the claims.
  • Motivation to Combine: A POSITA would combine Best and Oktay because both relate to immersion cooling of electronic components. Petitioner argued that the fluid overflow and collection mechanism in Oktay is "remarkably similar" to that claimed in the ’457 patent, making it an obvious and known technique to incorporate into a system like Best's for efficient fluid recovery.
  • Expectation of Success: Success would be expected, as modifying Best's system with Oktay's well-understood overflow and collection method represents a straightforward application of known fluid handling principles to achieve the predictable benefit of organized fluid recovery.

• Additional Grounds: Petitioner asserted an additional obviousness challenge based on the combination of Best and Gryzhin (Russian Federation Patent No. 2500013C1), where Gryzhin was also alleged to teach the weir/reservoir limitation. Petitioner also argued claims 11 and 14 are obvious over Best alone, as these claims omit the key reservoir limitation that was added during prosecution specifically to overcome rejections based on Best.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate because the key prior art references presented in the petition (Krajewski, Cray, Oktay, and Gryzhin) were never substantively considered by the Examiner. Petitioner contended the patent was allowed only because the Examiner mistakenly relied on a non-prior art reference for the critical weir/reservoir limitation and, upon discovering the error, failed to conduct a proper search for or consider other art teaching that feature.
• Petitioner also argued that discretionary denial under Fintiv is unwarranted. The co-pending district court litigation was described as being in its early stages, with no claim construction rulings issued and no depositions taken. Furthermore, the key prior art asserted in the petition was not at issue in the district court case, meaning the issues do not substantially overlap.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1, 5, 6, 10, 11, and 14 of the ’457 patent as unpatentable under 35 U.S.C. §103.