PTAB

IPR2013-00096

HOneyWell Intl Inc v. HVAC Modulation Technologies LLC

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1. Case Identification

2. Patent Overview

  • Title: CONTROL METHODS AND APPARATUS FOR GAS-FIRED COMBUSTORS
  • Brief Description: The ’642 patent describes a control system for gas-fired burner apparatus, such as furnaces and boilers. The system is designed to modulate multiple inputs—including fuel flow, combustion air supply, and heat transfer medium (circulating air) flow—to continuously balance the heat supplied to a space with the changing heating load.

3. Grounds for Unpatentability

Ground 1: Anticipation and Obviousness over the GRI Reference - Claims 1-4, 6-7, 9-12, and 14-22 are anticipated or obvious over the GRI Reference, alone or in view of secondary references.

  • Prior Art Relied Upon: GRI Reference (a Jan. 1991 final report from the Gas Research Institute, the original assignee of the ’642 patent); Rheem 1 (a 1970 brochure for the New Imperial Gas Furnace); Rheem 2 (a 1969 brochure for the Solid State Breakthrough furnace); Stroud (Patent 3,967,614); and Rogers (Patent 4,607,787).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the GRI Reference, which was not considered during the original prosecution or a subsequent ex parte reexamination, anticipates all limitations of independent claims 1, 9, and 16. The patentability of these claims after reexamination hinged on the addition of a modulating combustion air blower controlled in concert with the fuel flow and circulation air. The Petitioner contended that the GRI Reference explicitly discloses this key feature, describing a system with: (1) continuous modulation of firing rate (fuel), (2) continuous modulation of supply air (circulation), and (3) continuous modulation of combustion air using an ECM-driven inducer blower to maintain efficiency. Petitioner asserted that the GRI Reference teaches modulating all three inputs via a microprocessor-based controller to match heating output to the heating load, thus anticipating the core invention.
    • Motivation to Combine (for §103 grounds): For claims requiring additional features, Petitioner argued a person of ordinary skill in the art (POSITA) would have been motivated to combine the references. For claim 16 (monitoring temperature at the heat exchanger), the GRI Reference noted that such sensors were a known but sometimes unnecessary option. Petitioner asserted a POSITA would combine GRI's furnace with the temperature sensor taught in Rheem 1 or Rheem 2 to achieve the known benefit of maintaining a constant supply air temperature and enhancing comfort. For claim 17 (monitoring return air temperature), a POSITA would incorporate the return-duct sensor from the ’787 patent into the GRI system to gain the ’787 patent’s disclosed efficiency benefits.
    • Expectation of Success (for §103 grounds): Because the GRI Reference taught a comprehensive modulating furnace and the secondary references taught discrete, well-understood components (like temperature sensors) for their known purposes, a POSITA would have had a high expectation of success in combining them to achieve predictable improvements.

Ground 2: Anticipation and Obviousness over Thompson - Claims 1, 2, 4, 6, 10, 12, 15-18, and 20-23 are anticipated or obvious over Thompson, alone or in view of secondary references.

  • Prior Art Relied Upon: Thompson (Patent 6,648,551, referred to as the ’551 patent); Rheem 1; Rheem 2; and Rogers (Patent 4,607,787).
  • Core Argument for this Ground:
    • Prior Art Mapping: As an alternative primary reference, Petitioner argued the ’551 patent discloses a fully modulated gas furnace that anticipates the challenged claims. The ’551 patent, also not previously considered by the PTO, allegedly teaches a microprocessor controller that modulates: (1) fuel flow via a gas regulator valve, (2) circulating air via an ECM blower, and (3) combustion air via an inducer blower to ensure an "optimum combustion air flow rate." Petitioner contended the ’551 patent's disclosure of a controller modulating these three inputs in response to heating demand renders claims 1, 9, and their dependents anticipated. The patent's disclosure of operating in high and low heating modes, plus a distinct calibration mode, was argued to meet the "at least three respective rates of operation" limitation.
    • Motivation to Combine (for §103 grounds): The motivation arguments were similar to those for Ground 1. For claim 16 (monitoring temperature at the heat exchanger), Petitioner argued a POSITA would have been motivated to add the sensor from Rheem 1 or Rheem 2 to the ’551 patent’s furnace to gain the known comfort benefits of constant supply air temperature. For claim 23 (which recites modulating only two inputs but adds monitoring return air temperature), a POSITA would combine the furnace of the ’551 patent with the return-duct sensor from the ’787 patent to improve the system's response to heating loads, a benefit explicitly taught by the ’787 patent.

4. Key Claim Construction Positions

  • Petitioner argued for constructions of several means-plus-function limitations based on the ’642 patent’s specification, consistent with interpretations made during the prior reexamination. These constructions were critical to mapping the prior art.
  • "Means for modulating the flow of fluid fuel" (Claim 1.3): Construed as a modulating gas valve controlled by an electric signal. This allowed Petitioner to map the pulse-width-modulating valve of the GRI Reference and the solenoid-controlled gas regulator of the ’551 patent to this limitation.
  • "Means for circulating the heat transfer medium" (Claim 1.5): Construed as a circulating air blower. This structure was directly disclosed in both the GRI Reference and the ’551 patent.
  • "Control means" (Claim 1.8): Construed as a controller (e.g., a microprocessor). This allowed Petitioner to map the microprocessor-based controllers described in both the GRI Reference and the ’551 patent, which integrate and control the modulating components, to this limitation.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-4, 6-7, 9-12, and 14-23 of the ’642 patent as unpatentable under 35 U.S.C. §102 and/or §103.