Green Revolution Cooling Inc v. Midas Green Technologies LLC

1. Case Identification

• Case #: IPR2025-00196
• Patent #: 10,405,457
• Filed: November 19, 2024
• Petitioner(s): Green Revolution Cooling, Inc.
• Patent Owner(s): Midas Green Technologies, LLC
• Challenged Claims: 1-16

2. Patent Overview

• Title: Appliance Immersion Cooling System
• Brief Description: The ’457 patent relates to electrical appliance cooling systems, specifically an improved immersion cooling system for electronic components such as computer servers. The invention describes a tank containing a dielectric fluid, a plenum for dispensing the fluid, and a weir for recovering the fluid to facilitate a continuous cooling circulation loop.

3. Grounds for Unpatentability

Ground 1: Claims 1-16 are obvious over Best-2008 in view of Osada

• Prior Art Relied Upon: Best-2008 (Application # 2011/0132579) and Osada (Japanese Patent Application Publication No. 2001-181898).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Best-2008 taught a complete immersion cooling system with nearly all claimed elements, including a tank for immersing servers, a primary circulation facility with pumps and heat exchangers, and a control system. Best-2008’s system used outlet pipes to remove heated coolant. Petitioner argued that the primary missing limitations—a weir integrated into the tank wall and an external fluid recovery reservoir positioned beneath the weir's overflow lip—were disclosed by Osada. Osada taught a similar open-air immersion tank system that used a "widely-used" and "conventional" rectangular weir and an external "overflow box" to manage fluid levels and facilitate filtration.
  • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would be motivated to combine Osada's weir system with Best-2008's immersion tank. Both references are in the same field and address common goals of temperature control, fluid level management, and impurity removal. A POSITA would have recognized Osada's weir as a known, predictable, and superior alternative to Best-2008's simple outlet pipes for achieving uniform fluid recovery and improved filtration. The combination was presented as the application of a known technique to a similar system to yield predictable results.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because implementing Osada's weir and overflow box would involve a straightforward mechanical reconfiguration of the Best-2008 tank. The components were conventional and their function within liquid circulation systems was well understood.

Ground 2: Claims 1-16 are obvious over Best-2008 in view of Osada and Best-2012

• Prior Art Relied Upon: Best-2008 (Application # 2011/0132579), Osada (Japanese Patent Application Publication No. 2001-181898), and Best-2012 (Application # 2014/0211412).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground incorporated the arguments from Ground 1 and added Best-2012 to further support the limitation that the weir is integrated "adjacent all appliance slots" to facilitate "substantially uniform recovery" of the dielectric fluid. Petitioner contended that Best-2012, filed by the same inventor as Best-2008, explicitly taught the benefits of a structure extending along the entire length of the tank to ensure uniform coolant flow. Specifically, Best-2012 disclosed a suction manifold with uniformly spaced nozzles/orifices along the tank's long wall to achieve flow that is "approximately equal along the length of the entire tank."
  • Motivation to Combine: Petitioner argued that Best-2012 confirmed the obviousness of implementing Osada's weir-and-notch system in a manner that extends across all appliance slots. A POSITA, seeking to achieve the uniform flow described as a goal in Best-2008 and enabled by Osada's weir, would find clear motivation in Best-2012 to arrange the weir's overflow notches uniformly along the tank wall, adjacent to each appliance slot, to achieve the desired effect.
  • Expectation of Success: Success was reasonably expected because Best-2012 provided a direct and analogous teaching for achieving uniform fluid extraction along a tank wall, confirming the design principles that a POSITA would apply when integrating Osada's weir into the Best-2008 system.

4. Key Claim Construction Positions

• Petitioner argued that while no formal constructions were required, it adopted certain positions for clarity based on the prosecution history and prior litigation.
• "a weir... adjacent all appliance slots": Petitioner adopted the Patent Owner's prior argument that this phrase requires the weir to extend substantially the entire length of the tank's long wall adjacent to all the appliance slots to ensure uniform fluid recovery.
• "a weir... having an overflow lip": Petitioner contended that, consistent with the examiner's view during prosecution, the "weir" is an opening in a wall and its "overflow lip" is merely the bottom surface of that opening, without any further required structural features. The petition asserted that Patent Owner failed to identify specification support for any greater structural limitation during prosecution.

5. Arguments Regarding Discretionary Denial

• Petitioner presented extensive arguments that discretionary denial would be inappropriate under 35 U.S.C. §314(a) (based on Fintiv factors) and 35 U.S.C. §325(d).
• §314(a) / Fintiv: Petitioner argued that denial is unwarranted primarily because it filed a broad Sotera stipulation, agreeing not to pursue in the parallel district court litigation any invalidity grounds that were raised or could have been reasonably raised in the IPR. Petitioner asserted this stipulation is dispositive under current USPTO guidance. It also argued the litigation was in its early stages, with a distant and uncertain trial date.
• §325(d) / Advanced Bionics: Petitioner argued against denial because its grounds were not the same or substantially the same as those considered during prosecution. It contended that the examiner never considered Osada or Best-2012, and these references directly supply the weir and recovery reservoir limitations that the applicant added to overcome the examiner's rejections based on Best-2008 alone. Therefore, the petition raised new arguments and art combinations presenting a materially different invalidity challenge.

6. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-16 of Patent 10,405,457 as unpatentable.