PTAB

IPR2017-01000

MEras Engineering Inc v. CH2O Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method of Promoting Unrestricted Flow of Irrigation Water
  • Brief Description: The ’550 patent discloses a method for removing bacterial growths (biofilm) and mineral deposits that clog agricultural drip irrigation systems. The method involves admixing a biofilm reducing agent (BRA), such as a chlorite salt, and a mineral deposit distorting agent (MDDA), such as a phosphonate, into the irrigation water.

3. Grounds for Unpatentability

Ground 1: Obviousness over Iverson in view of Miller - Claims 1, 5-10, and 13-27 are obvious over Iverson in view of Miller.

  • Prior Art Relied Upon: Iverson (Patent 6,767,470) and Miller (Patent 6,036,740).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Iverson, which is also assigned to the Patent Owner, taught the core invention by disclosing a method of cleaning generic irrigation systems by combining a sodium chlorite solution (the BRA) with a second solution containing an acidic antiscalant like PBTC (the MDDA) to remove both biofilm and mineral deposits. Petitioner asserted that Miller supplied the few limitations not explicitly taught by Iverson. Specifically, Miller taught the use of antiscalants in a "drip irrigation" system with clog-prone "discharge emitters," and expressly disclosed the use of specific phosphonates like HEDP (recited in challenged claim 8). For dependent claims reciting specific concentration ranges of chlorine dioxide and mixed oxidants, Petitioner argued Iverson disclosed an overlapping range (0.5 ppm), establishing a prima facie case of obviousness. Alternatively, Petitioner contended that a person of ordinary skill in the art (POSITA) would have arrived at the claimed concentrations through routine experimentation to optimize the known process.
    • Motivation to Combine: A POSITA would combine Iverson and Miller because both address the identical problem of mineral and biological fouling in irrigation systems using similar chemical agents. Petitioner argued there was a strong motivation to apply Iverson’s general cleaning method to the specific, well-known "drip irrigation systems" taught by Miller, as the smaller emitters in such systems are particularly susceptible to the clogging Iverson sought to prevent. Furthermore, a POSITA looking to implement Iverson’s method, which calls for an acidic phosphonate antiscalant, would have been motivated to consult a reference like Miller, which identifies a list of suitable and commercially available phosphonates, including HEDP.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because applying Iverson’s chemical treatment to Miller’s drip irrigation system was a simple application of a known solution to a known problem, and using an alternative known phosphonate like HEDP from Miller in Iverson’s system would be a predictable substitution.
    • Key Aspects: A central component of Petitioner’s argument rested on the Patent Owner’s contradictory statements regarding Iverson. During reexamination of the ’550 patent, the Patent Owner overcame an Iverson-based rejection by arguing that its claimed invention involved a "slow release" of chlorine dioxide, whereas Iverson taught a "fast generation." However, in a separate district court litigation where it asserted the Iverson patent, the Patent Owner admitted that Iverson's reaction time is variable, can be controlled by the user, and may proceed slowly. Petitioner leveraged these litigation admissions to argue that the purported distinction of a "slow release" was a sham and that Iverson inherently taught the claimed limitation.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that this inter partes review (IPR) was not redundant in view of prior Patent Office proceedings. It contended that the specific combination of Iverson and Miller had never been considered by the examiner during prosecution, reexamination, or reissue.
  • Crucially, Petitioner asserted that the Patent Office never had the opportunity to consider the Patent Owner's own contradictory litigation admissions regarding the reaction speed taught in Iverson. These admissions, Petitioner argued, directly undermined the arguments the Patent Owner used to secure allowance of the claims and demonstrated that the ’550 patent is unpatentable.

5. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1, 5-10, and 13-27 of the ’550 patent as unpatentable under 35 U.S.C. §103.