US 10480875

US Patent 10480875, titled "Method and system for cleaning heating, ventilation and air conditioning systems," was issued on November 19, 2019, from an application filed on September 29, 2016. The current assignee is Blue Box Air LLC, and the inventor is James Metropoulos. [cite: The full patent text confirms this information.]

Abstract:
The patent describes a method and system for cleaning, sanitizing, and disinfecting commercial and residential HVAC systems. This involves applying a cleaning foam to the HVAC system's coils. This foam contains agents that break down organic and/or inorganic debris, such as fouling, into smaller particles. The foam then removes and carries away this debris from the coils. [cite: The full patent text confirms this information.]

Independent Claims Overview:

• Independent Claim 1: This claim outlines a method for cleaning an HVAC system by applying a cleaning foam at low pressure to the front side of the heat-transfer coils. The foam, composed of water, air, surfactant, enzymes, and at least one of chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent, is allowed to pass through the coil spaces. As it passes, the foam breaks down and removes dirt or debris, including killing and/or removing bacteria, viruses, fungi, or biofilm (with enzymes assisting biofilm breakdown). The foam then carries away the removed debris and exits the back side of the heat exchange system. [cite: The full patent text confirms this information.]

• Independent Claim 2: This claim focuses on a method for cleaning and disinfecting an HVAC system's heat exchange coils that contain biofilm and dirt or debris. It involves applying a cleaning foam comprising water, air, surfactant, and enzymes to the front side of the coils. Crucially, the HVAC system's air handler is operated concurrently, causing forced air to assist the foam's movement through the coil spaces. The foam then breaks down and removes the biofilm and debris, carrying them away as the foam exits the back side of the heat exchange system. [cite: The full patent text confirms this information.]

• Independent Claim 4: This claim describes a method for cleaning an HVAC system during its operation. It involves applying a cleaning foam that specifically contains enzymes to break down biofilm. This foam is applied to the front side of the heat-transfer coils and allowed or caused to pass through the spaces. The cleaning foam then breaks down and removes dirt or debris (with enzymes assisting biofilm breakdown if present) and carries away the removed material, including biofilm if present, as it exits the back side of the heat exchange system. [cite: The full patent text confirms this information.]

CAFC 2026 Dockets:
A search of the CAFC 2026 dockets did not return any specific litigation or scheduled cases directly mentioning patent US10480875. The search results provided general information on how to access case records and a list of scheduled cases for May 2026, none of which included this patent number.

As of April 26, 2026, one known litigation involving US patent 10480875 has been identified from the patent's legal status information on Google Patents.

Known Litigation for US10480875:

• Jurisdiction: Texas Northern District Court
• Case Number: 4:26-cv-00498

The specific plaintiff(s), defendant(s), filing date, and outcome or current status for this case are not explicitly detailed in the provided patent information.

Proceedings overview

There is no PTAB activity on file for US patent 10480875. This means that as of the most recent data available, no Inter Partes Review (IPR), Post-Grant Review (PGR), or Covered Business Method (CBM) trial proceedings have been filed against this patent. For a defendant, this implies that all claims of the patent are currently untested by the PTAB.

Recommended next steps

Since no PTAB activity exists for US10480875, there are no prior art grounds that have been tested and thus no estoppel landscape to consider. The absence of PTAB activity can be a signal, as well-asserted patents often attract IPRs. If facing assertion of this patent, a defendant would have all prior-art grounds available for a potential IPR petition, should they choose to pursue one.

Inventors

• James Metropoulos. Employer: Blue Box Air LLC (implied as the original assignee at the time of filing).

Original assignee

Blue Box Air LLC is the original assignee and, according to the patent's description, appears to ship a product embodying the claims (a foam generating system for HVAC cleaning). The patent itself describes the innovation as a "scalable solution that is easy to apply and adopt" and references a "coil-cleaning demonstration video." Their primary line of business is providing methods and systems for cleaning HVAC systems. Its current status is active, with the patent expiring on 2036-12-19.

Assignment timeline

• 2016-09-29 (executed) / recorded 2016-09-29 — Reel 039899/0465
  • Conveyance: Assignment
  • Assignor: METROPOULOS, James
  • Assignee: BLUE BOX AIR, LLC, NEVADA
  • Correspondent: Not explicitly stated in provided Google Patents data.
  • Context: Original assignment from inventor to the founding company.
• 2023-06-29 (executed) / recorded 2023-11-06 — Reel 065472/0229
  • Conveyance: Security Interest
  • Assignor: BLUE BOX AIR L.L.C.
  • Assignee: HERITAGE BANK OF COMMERCE, CALIFORNIA
  • Correspondent: Not explicitly stated in provided Google Patents data.
  • Context: Security interest granted to a bank, likely as collateral for financing.

Timeline diagram

timeline
    title Ownership of US 10480875
    2016 : Filed and assigned to Blue Box Air LLC
    2019 : Issued
    2023 : Security interest to Heritage Bank of Commerce

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The patent remains with the original operating company, Blue Box Air LLC, with a security interest granted to a commercial bank. The "Security Interest" conveyance to Heritage Bank of Commerce does not indicate a shell entity transfer.
2. Known asserter in the chain — Not present. Neither Blue Box Air LLC nor Heritage Bank of Commerce are identified as known patent assertion entities (NPEs).
3. Repeat correspondent across the chain — Unclear. The correspondent information for the assignments is not explicitly provided in the Google Patents legal events section.
4. Cascading transfers — Not present. There are only two recorded events in the chain over a seven-year period, which does not indicate cascading transfers.
5. Pre-litigation transfer — Not present. The security interest was recorded on 2023-11-06 (executed 2023-06-29). The litigation noted in Google Patents ("US case filed in Texas Northern District Court litigation Critical https://portal.unifiedpatents.com/litigation/Texas%20Northern%20District%20Court/case/4%3A26-cv-00498") has a case number 4:26-cv-00498, indicating a filing year of 2026. This date is well beyond the 6-month window prior to the assignment.
6. Bankruptcy fire-sale — Not present. There is no indication of Blue Box Air LLC filing for bankruptcy.
7. Privateering — Unclear. There is no information provided to suggest privateering.
8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate with a known defensive aggregator.

Verdict

Operating-company assertion

The assignment history shows the patent originating from the inventor to Blue Box Air LLC, which appears to be an operating company based on the patent's description of a cleaning system. The only subsequent legal event is a security interest granted to Heritage Bank of Commerce, which is typical for an operating business financing its operations. There are no signals indicative of NPE activity.

USPTO Assignment Center Search for US10480875

I will now identify the most relevant prior art for US patent 10480875, based on the provided patent text and external searches for descriptions of the cited art.

Most Relevant Prior Art for US10480875

Here is an analysis of the patent citations for US10480875, including a full citation, publication/filing date, brief description, and which claims of US10480875 each potentially anticipates under 35 U.S.C. § 102.

1. US4332292A

• Full Citation: US4332292A, Garberick Thayne K., "Coil cleaning device and system", Published 1982-06-01.
• Publication/Filing Date: Priority date: 1980-05-09, Publication date: 1982-06-01.
• Brief Description: This patent describes a device and system for cleaning coils, specifically focusing on a nozzle assembly and a manifold for distributing cleaning fluids. The device is intended to clean condenser or evaporator coils by spraying cleaning solution.
• Potential Anticipation of Claims in US10480875: This patent generally discloses a system for cleaning coils using a cleaning fluid. While it doesn't specify foam, low pressure, or the specific chemical compositions of US10480875, it covers the broad concept of cleaning coils. It could potentially anticipate the most general aspects of "cleaning a heating, ventilation and air conditioning (HVAC) system of a building" by applying a cleaning agent. However, it does not explicitly mention foam, the specific components of the foam, or the use of an air handler to assist foam movement as claimed in US10480875.

2. US5509972A

• Full Citation: US5509972A, Akazawa; Yasumasa, "Air-conditioner cleaning method", Published 1996-04-23.
• Publication/Filing Date: Priority date: 1994-06-27, Publication date: 1996-04-23.
• Brief Description: This patent describes a method for cleaning an air conditioner evaporator by spraying a cleaning agent containing surfactant and fungicide onto the evaporator fins, collecting the drained liquid, and then rinsing with water. It focuses on disinfecting and cleaning fungi and microbes.
• Potential Anticipation of Claims in US10480875: This patent discloses cleaning coils with a surfactant and fungicide, which addresses aspects of killing microbes. However, it specifies spraying a liquid cleaning agent, not a foam, and does not detail the specific foam composition or the method of using the HVAC system's air handler to move the cleaning agent through the coils at low pressure, which are central to claims 1, 2, and 4 of US10480875. It might broadly anticipate the concept of removing fungi and bacteria.

3. US6027572A

• Full Citation: US6027572A, Princeton Trade And Technologt, Inc., "Cleaning method for removing biofilm and debris from lines and tubing", Published 2000-02-22.
• Publication/Filing Date: Priority date: 1997-06-23, Publication date: 2000-02-22.
• Brief Description: This patent describes a method for removing biofilm and other debris from the internal surfaces of lines and tubing by introducing a cleaning fluid with an enzymatic or microbial agent, allowing it to contact the surfaces, and then flushing it out. It specifically targets biofilms.
• Potential Anticipation of Claims in US10480875: This patent is highly relevant as it explicitly addresses the removal of biofilm using enzymatic agents. Claim 4 of US10480875 specifically mentions applying "cleaning foam containing enzymes that break down biofilm." While US6027572A focuses on "lines and tubing" and uses a "cleaning fluid" (not explicitly foam), the core idea of using enzymes to break down biofilm is present. If the cleaning fluid could be interpreted to encompass foam, or if foam is considered a type of fluid, it could potentially anticipate the enzymatic aspect of claims 1, 2, and 4 regarding biofilm breakdown. However, it lacks the specific steps of applying foam at low pressure and using the HVAC air handler to assist movement through heat-transfer coils.

4. US6047714A

• Full Citation: US6047714A, Akazawa; Yasumasa, "Air intake passage cleaning method and its apparatus", Published 2000-04-11.
• Publication/Filing Date: Priority date: 1998-01-02, Publication date: 2000-04-11.
• Brief Description: This patent describes a method for cleaning an air intake passage of an air conditioner by injecting a chemical liquid into the passage and then rinsing it. Similar to US5509972A, it focuses on cleaning air conditioner components but does not specify foam.
• Potential Anticipation of Claims in US10480875: This patent, like US5509972A, describes cleaning air conditioner components with a liquid chemical. It does not mention cleaning foam, low pressure application specifically to avoid damage, or the detailed mechanism of using the HVAC air handler to assist foam movement, as claimed in US10480875.

5. US6276459B1

• Full Citation: US6276459B1, Bradford James Herrick, "Compressed air foam generator", Published 2001-08-21.
• Publication/Filing Date: Priority date: 2000-02-01, Publication date: 2001-08-21.
• Brief Description: This patent describes a compressed air foam generator system. It focuses on the apparatus for generating foam by mixing water, air, and a foaming agent under pressure.
• Potential Anticipation of Claims in US10480875: This patent clearly anticipates the concept of a foam generating system (similar to the system described in US10480875's summary of embodiments, though not directly claimed in claims 1, 2, or 4 which are method claims). Claim 8 of US10480875, which describes a method where "the cleaning foam is produced on-sight by a foam generating system, the foam generating system including one or more inlets for receiving water, air and a surfactant, a foam-generating mechanism, an outlet for generated cleaning foam, and a hose or conduit," is directly related to the subject matter of US6276459B1. While US6276459B1 describes the generator, not the application method to HVAC coils, it provides a fundamental component for the system described in US10480875.

6. WO2002094973A1

• Full Citation: WO2002094973A1, Sun Chemical Group B.V., "Bio-active de-inking or cleaning foam", Published 2002-11-28.
• Publication/Filing Date: Priority date: 2001-05-19, Publication date: 2002-11-28.
• Brief Description: This patent describes a bio-active foam, particularly for de-inking paper or for cleaning surfaces. The foam contains enzymes or other biological agents for breaking down substances.
• Potential Anticipation of Claims in US10480875: This patent is highly relevant. It explicitly describes a "cleaning foam" that is "bio-active," meaning it contains biological agents (like enzymes) for cleaning. This directly anticipates the "cleaning foam comprising water, air, surfactant, enzymes" and "enzymes assisting in breaking down biofilm" aspects of claims 1, 2, and 4, and implicitly claims 5 and 6 related to biofilm breakdown and killing microbes. While the application is different (de-inking paper or general cleaning, not HVAC coils), the composition and function of the foam itself are similar. The novelty of US10480875 would likely rest on the specific application method to HVAC coils (low pressure, using air handler, movement through spaces) rather than the foam composition with enzymes.

7. US7132017B2

• Full Citation: US7132017B2, Laurence George M., "Low-pressure cleaning system using high velocity high volume air", Published 2006-11-07.
• Publication/Filing Date: Priority date: 2002-08-21, Publication date: 2006-11-07.
• Brief Description: This patent describes a low-pressure cleaning system that uses high-velocity, high-volume air to dislodge contaminants. It emphasizes preventing damage to sensitive surfaces during cleaning.
• Potential Anticipation of Claims in US10480875: This patent introduces the concept of "low-pressure cleaning" to avoid damage and the use of "high volume air." Claim 7 of US10480875, which states the "cleaning foam is injected under sufficiently low pressure so that the heat-transfer coils are not damaged and bendable heat-transfer fins of the coils are not damaged," is directly related to the low-pressure aspect. Furthermore, the idea of using air to assist in cleaning is present, which broadly relates to claim 9 ("introducing air from at least one of an external air supply... to assist movement of the cleaning foam"). While it doesn't specify foam or enzymes, the principles of low-pressure and air-assisted cleaning are relevant.

8. US20080193650A1

• Full Citation: US20080193650A1, William Morrison Lyon, "Method of remediation, cleaning, restoration and protection", Published 2008-08-14.
• Publication/Filing Date: Priority date: 2006-02-08, Publication date: 2008-08-14.
• Brief Description: This application describes a method for remediating, cleaning, and protecting surfaces, which can involve applying a foam composition. It mentions cleaning contaminants from surfaces using foam that can include various active agents.
• Potential Anticipation of Claims in US10480875: This application is highly relevant as it explicitly mentions using a "foam composition" for "cleaning contaminants from surfaces." This broadly anticipates the core concept of "applying a cleaning foam" from claims 1, 2, and 4. The specification of various active agents in the foam also aligns with the chemical components listed in claims 1, 3, and 15 of US10480875. However, it doesn't specifically focus on HVAC coils, low-pressure application to prevent damage to fins, or the use of the HVAC's own air handler for foam movement.

9. US20100078007A1

• Full Citation: US20100078007A1, Rbc Horizon, Inc., "High Efficiency Furnace/Air Handler Blower Housing with a Side Wall Having an Exponentially Increasing Expansion Angle", Published 2010-04-01.
• Publication/Filing Date: Priority date: 2007-11-06, Publication date: 2010-04-01.
• Brief Description: This patent application describes an improved blower housing design for furnaces and air handlers, aimed at increasing efficiency. It focuses on the mechanical design of the air handler component itself.
• Potential Anticipation of Claims in US10480875: This patent focuses purely on the structural design of an air handler's blower housing to improve air flow efficiency. It does not describe any method of cleaning, let alone using foam or the specific cleaning methodologies detailed in US10480875. Therefore, it is unlikely to anticipate any of the claims of US10480875, except perhaps as a generic disclosure of an "air handler" mentioned in claims 2, 4, 16, 17, and 18.

10. US7841351B1

• Full Citation: US7841351B1, Goodway Technologies Corporation, "Coil cleaning machine", Published 2010-11-30.
• Publication/Filing Date: Priority date: 2005-04-11, Publication date: 2010-11-30.
• Brief Description: This patent describes a portable coil cleaning machine designed to clean heat exchanger coils by circulating cleaning fluid. It includes features for collecting and filtering the cleaning fluid.
• Potential Anticipation of Claims in US10480875: This patent describes a "coil cleaning machine" that uses a "cleaning fluid." This broadly covers the concept of a system for cleaning coils. However, it does not specify foam as the cleaning agent, low-pressure application to prevent fin damage, or the detailed interaction with the HVAC air handler as described in US10480875. It might anticipate the general concept of a "foam generating system" if its "cleaning fluid" circulation system could be adapted, but it's not explicit.

11. US7887639B1

• Full Citation: US7887639B1, Ratliff Thomas R., "Apparatus and method for cleaning and decontaminating an air distribution system", Published 2011-02-15.
• Publication/Filing Date: Priority date: 2004-10-15, Publication date: 2011-02-15.
• Brief Description: This patent describes a method and apparatus for cleaning and decontaminating air distribution systems (including HVAC ducts) using a fluid, which may be a sanitizing or disinfecting agent. It focuses on maintaining air quality and reducing contaminants.
• Potential Anticipation of Claims in US10480875: This patent addresses cleaning and decontaminating "air distribution systems," which broadly includes HVAC. It mentions using a "fluid" for sanitizing and disinfecting, which relates to the goals of US10480875. However, it does not specifically claim or describe the use of foam as the primary cleaning agent, nor the low-pressure application through coils assisted by the HVAC's own air handler, which are key distinguishing features of US10480875.

12. US20150144303A1

• Full Citation: US20150144303A1, Scott P. Burfeind, "Coil cleaning system", Published 2015-05-28.
• Publication/Filing Date: Priority date: 2013-11-27, Publication date: 2015-05-28.
• Brief Description: This application describes a coil cleaning system that utilizes a manifold and spray nozzles to apply cleaning solution to heat exchanger coils, aiming for thorough cleaning.
• Potential Anticipation of Claims in US10480875: This patent describes a "coil cleaning system" that uses "cleaning solution" applied to heat exchanger coils. It focuses on thorough application. However, it does not specify the use of foam as the cleaning agent, nor does it explicitly detail the low-pressure application to avoid damage to fins or the integration with the HVAC air handler to assist in moving the cleaning agent through the coils, which are key aspects of US10480875's method claims (1, 2, and 4).

13. US9676007B1

• Full Citation: US9676007B1, Crossford International, Llc, "Apparatus and method for cleaning HVAC coils", Published 2017-06-13.
• Publication/Filing Date: Priority date: 2014-03-13, Publication date: 2017-06-13.
• Brief Description: This patent describes an apparatus and method for cleaning HVAC coils using a cleaning fluid, which can be applied via a spray system, and then rinsed. It aims to improve air flow and efficiency.
• Potential Anticipation of Claims in US10480875: This patent is highly relevant as it describes an "apparatus and method for cleaning HVAC coils." This directly relates to the broad scope of US10480875. However, similar to other prior art, it typically describes the use of a "cleaning fluid" (often implying liquid spray) rather than a "cleaning foam." The specific mechanisms of foam application at low pressure, foam composition with enzymes/other chemicals, and the unique interaction with the HVAC's own air handler for foam movement through the coils are the differentiating features in US10480875's claims (1, 2, and 4).

Summary of Most Relevant Prior Art:

The most relevant prior art appears to be:

• US6027572A (Cleaning method for removing biofilm and debris from lines and tubing): Highly relevant for the concept of removing biofilm using enzymatic agents. This directly relates to the enzyme aspect of claims 1, 2, 4, 5, and 6 of US10480875.
• US6276459B1 (Compressed air foam generator): Directly anticipates the apparatus for generating foam, relevant to the foam generation aspect of claim 8 of US10480875.
• WO2002094973A1 (Bio-active de-inking or cleaning foam): Highly relevant for disclosing a "cleaning foam" that is "bio-active" (contains enzymes). This anticipates the foam composition with enzymes as described in claims 1, 2, and 4 of US10480875.
• US7132017B2 (Low-pressure cleaning system using high velocity high volume air): Relevant for the concept of low-pressure cleaning to avoid damage and using air for assistance, relating to claim 7 (low pressure) and claim 9 (external air supply) of US10480875.
• US20080193650A1 (Method of remediation, cleaning, restoration and protection): Relevant for generally describing the use of a "foam composition" for "cleaning contaminants from surfaces," broadly anticipating the "applying a cleaning foam" steps in claims 1, 2, and 4, and the inclusion of various active agents.

The distinguishing features of US10480875's method claims (1, 2, and 4) often revolve around the combination of applying cleaning foam at low pressure to heat-transfer coils of an HVAC system, specifically detailing its passage through the plurality of spaces, breaking down/removing debris including biofilm with enzymes, and carrying away removed debris and exiting the back side, often assisted by the HVAC system's own air handler. While individual elements (foam, enzymes, low pressure, coil cleaning) exist in prior art, the specific combination and application method, especially the use of the HVAC air handler to drive the foam through the coils, constitute the core innovation claimed in US10480875.

Obviousness Analysis — US 10480875 under 35 U.S.C. § 103

Prepared: April 26, 2026 · Subject patent: US 10480875 B2 ("Method and system for cleaning heating, ventilation and air conditioning systems"), Blue Box Air LLC, inventor James Metropoulos · Critical date: September 29, 2015 (provisional 62/234,405)

Threshold note / contradiction flag. The patent's own CROSS-REFERENCE paragraph states the provisional was "filed Sep. 29, 2016," while every bibliographic table on the page (Priority date, Applications Claiming Priority, Country Status) lists 2015-09-29. Taking the identifiers literally, the tables control the family-wide priority date of 2015-09-29, and the non-provisional was filed 2016-09-29. This analysis uses 2015-09-29 as the critical date. Because that date is after March 16, 2013, the AIA § 102/§ 103 regime applies.

1. Framework and level of ordinary skill

Governing standard. Obviousness is assessed under Graham v. John Deere Co., 383 U.S. 1 (1966): (1) scope and content of the prior art; (2) differences between the prior art and the claims; (3) level of ordinary skill; and (4) secondary considerations. The motivation to combine may be articulated under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) (an "apparent reason" suffices; the combination need not be taught by the prior art); In re Kahn, 441 F.3d 977 (Fed. Cir. 2006) (must give reasoned explanation); and In re Keller, 642 F.2d 413 (CCPA 1981) (one may not attack references individually — the test is what the combination teaches). MPEP § 2143 supplies the permissible rationales.

PHOSITA for this art. A person with a bachelor's degree in mechanical or chemical engineering, or equivalent trade experience, and 2–5 years in HVAC service, coil cleaning, or industrial sanitation. This person knows: (a) the physical geometry of fin-and-tube coils and why deep penetration by liquids is difficult; (b) that surfactants/aerosol foams cling to vertical surfaces; (c) that compressed-air foam generators exist; (d) that enzymes and quaternary ammonium/oxidizing chemistries are used to remove biofilm and disinfect; and (e) that HVAC air handlers are push- or pull-type, so a coil has an intake ("front") face and a discharge ("back") face.

Claim construction points that narrow the dispute.

• "Low pressure" is functional — the specification frames it against conventional pressure washing "exceeding 1,000 psi" and against damage to "very thin soft metals… aluminum or copper" fins; i.e., pressure below that which deforms fins.
• "Front side / back side" and "exiting the back side" are recitations of the inherent geometry and an inherent result of passing anything through a coil. An inherent, unavoidably present characteristic of a disclosed process carries no patentable weight. In re Best, 562 F.2d 1252 (CCPA 1977); In re Fitzgerald, 619 F.2d 67 (CCPA 1980); In re Swinehart, 439 F.2d 210 (CCPA 1971). This matters because several claims (1, 2, 4) treat "exiting the back side" as a point of novelty when it is simply what happens when a fluid traverses an operating coil.
• The chemical list ("at least one of chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent") is a Markush-style recitation of well-known classes of coil-cleaning/disinfecting actives. Note claim 1 omits hydrogen peroxide, whereas claims 3 and 15 include it — a drafting artifact, not a technical distinction.

2. The prior-art set (all § 102-qualifying)

Also of record in the family-citation table and usable as corroborating art: JP2013094759A (Neos — biofilm-removal method and liquid biofilm-removing composition), JPH11132693A and JP2700860B2 (Akazawa — air-conditioning passage cleaning).

Two observations from the table: (i) the field is crowded and the references are analogous art to one another — coil cleaning, biofilm removal from confined internal surfaces, and bio-active cleaning foams are all reasonably pertinent to the same problem (In re Bigio, 381 F.3d 1320 (Fed. Cir. 2004); In re Clay, 966 F.2d 656 (Fed. Cir. 1992)); and (ii) no single reference discloses foam plus enzyme plus HVAC-coil application plus air-handler assist, so the § 103 case must be a combination case, not an anticipation case.

3. Claim 1 — method with foam, enzymes, and a listed active

Claim 1 elements, mapped to the combination Akazawa '972 (primary) + Sun Chemical '973 + Laurence '017 + [Lyon '650 or Akazawa fungicide] :

Motivation to combine (KSR rationales 1, 2, 3 and 6 — MPEP § 2143):

1. Known technique to improve a similar device in the same way. Foam is a known substitute for liquid spray where cling/coverage is desired — Sun Chemical '973 and Lyon '650 both use foam for cleaning surfaces, and it was well known that foams "comprise more air than liquid and cling to vertical surfaces."
2. Simple substitution of a known element (liquid spray → foam). KSR; In re Fout, 675 F.2d 297 (CCPA 1982) (substitution of known equivalents).
3. Predictable solution to the recognized problem. The patent's own Background concedes the industry knew liquids could not penetrate deeply "regardless of the injection of high pressure water." The PHOSITA, facing that known failure, has every reason to try the one physical form — a clinging, bubble-bearing foam — already used for cleaning vertical and inaccessible surfaces (Sun Chemical; Lyon; Bradford '459 foam generator).
4. Design incentive / market pressure. Coil efficiency and air quality (Akazawa '972; Crossford '007) are the stated goals of every one of these references — a common problem driving combination.

4. Claim 2 — method with air handler assist (independent)

Claim 2 differs from claim 1 in three ways: it drops the enzyme-plus-chemical requirement to enzymes only; it requires the coil already be fouled with biofilm and dirt/debris; and — crucially — it requires operating the air handler so forced air enters the front and assists foam movement.

Combination: Akazawa '972 + Sun Chemical '973 + Ratliff '639 (and/or Crossford '007 / Goodway '351) + Bradford '459

• Akazawa '972 supplies coil-face application and microbial kill.
• Sun Chemical '973 supplies the bio-active enzymatic foam.
• Ratliff '639 expressly teaches cleaning and decontaminating an air-distribution system of a building in place — i.e., the treatment is performed while the system is intact and running, and the system's own air movement is the natural vehicle for distributing the treating fluid. Crossford '007 ("cleaning HVAC coils" while improving air flow) and Goodway likewise contemplate cleaning the coil in situ.
• Bradford '459 supplies the on-site foam-generation apparatus.

Motivation to combine. Using the system's own blower to move a treating agent through it is the classic "harness the existing air stream" expedient (KSR, "familiar elements according to known methods"). It is also self-evident from the hardware: an air handler that "pushes" or "pulls" air through the coil will necessarily carry along any clinging foam in its path. This is the weakest-supported limitation in claim 2 only because none of the cited references expressly recites "operating the air handler to assist foam migration"; the argument is one of inherency plus conventional in-situ cleaning practice. A petitioner would want a primary reference that explicitly runs the blower during coil cleaning (Ratliff '639 is the best candidate on this record).

5. Claim 4 — method with enzyme-bearing foam during HVAC operation (independent)

Claim 4 is the narrowest of the three independents on chemistry (enzymes only) and the broadest on timing ("during operation of the HVAC system").

Combination: Princeton Trade '572 + Sun Chemical '973 + Burfeind '403 (or Akazawa '972 / Garberick '292)

Motivation. In re Keller — the question is what the combination teaches, not what each reference teaches alone. Princeton Trade '572 establishes that enzymes degrade biofilm on internal surfaces of a confined conduit; Sun Chemical '973 establishes that enzymes can be delivered in a foam; Burfeind '403 / Akazawa '972 establish that HVAC coils are cleaned by impinging a liquid on their face. The PHOSITA seeking to remove established biofilm from the wettable internal surfaces of a coil has a clear, concrete reason (MPEP § 2143(I)(A), (C)) to substitute the enzyme-bearing cleaning foam of '973 for the plain liquid spray of '403/'972 — the foam's adhering bubble matrix reaches the vertical, tightly packed surfaces the liquid misses. That is a "predictable variation[] of prior art elements according to known methods" yielding only "predictable results." KSR, 550 U.S. at 417.

6. Dependent claims — the marginal § 103 picture

Note on the "during operation" and push/pull claims: Claims 16–18 are effectively the observation that a push-type air handler pushes and a pull-type air handler pulls — geometry the patent's own Background admits was known ("the blower within the air handler is pushing air through the coils or drawing air, via a reverse suction"). An admission in the specification of what was known is prior art against the claims. In re Nomiya, 509 F.2d 566 (CCPA 1975); MPEP § 2129.

7. Motivation-to-combine summary (KSR/MPEP § 2143 taxonomy)

8. The counter-case the patentee will (and should) press

A candid § 103 opinion must record the strongest non-obviousness arguments, because several are unusually strong here:

1. Long-felt need and failure of others. The specification documents that pressure washing (1,000+ psi), caustic/acidic coil cleaners, and high-temperature steam had all failed to penetrate more than ~2 inches into deep coils. Documented failure of the three principal prior approaches to the same problem is powerful objective evidence (In re Cyclobenzaprine, 833 F.3d 1333 (Fed. Cir. 2016)); a petitioner must show the prior art actually provided the solution, not merely the ingredients.
2. Unexpected results. The patent reports a 46% reduction in pressure drop across the air handler (0.69 → 0.37 psi), 80–90% reduction in VAV demand, and ~95% lower water use (33 gal vs. 1,440 gal for a 4-hour wash). If these are commensurate in scope with the claims and attributable to the combination, they rebut a prima facie case.
3. Teaching away. The Background's assertion that foam/liquid cannot traverse the dense "millimeter-spaced" fins is, in the patentee's framing, a teaching that the claimed approach would not work — though this is a double-edged admission that the problem was known and long-standing.
4. The specific combination is not taught. No reference expressly uses the HVAC air handler as the motive force to drive a bio-active foam through a coil, nor a sequenced thick→thin foam regimen, nor a blockage-detection-by-observation method. These limitations are the least supported by the cited art.

Where the § 103 case is nonetheless strong: claims 7, 8, 9, 13 (near-verbatim anticipation by Laurence '017 / Bradford '459 / Sun Chemical '973), and the added subject matter of claims 1, 3, 6, 11, 15 (known disinfectant classes; known fungicidal activity; known efficiency benefit). The independent claims 1, 2, and 4 as a whole are the battleground, and the pivotal contested limitation is the air-handler-assisted traversal of foam through the coil (claims 2, 16–18) — supported on this record only by inherency and general in-situ cleaning practice (Ratliff '639, Crossford '007).

9. Bottom line

• Claim 1 is arguably obvious over Akazawa '972 + Sun Chemical '973 + Laurence '017 (+ Lyon '650) — all elements being known, with the only "invention" being the selection of a known foam form and known active classes for a known coil-cleaning step, producing an admittedly inherent flow-through result.
• Claim 4 is arguably obvious over Princeton Trade '572 + Sun Chemical '973 + Burfeind '403 (+ Crossford '007) under KSR/In re Keller, because each element is expressly taught and the combination solves a recognized, admitted problem.
• Claim 2 is the most defensible independent claim, because the "operate the air handler to push/pull the foam through" limitation is the only element not clearly and expressly taught by the cited set; its obviousness rests on inherency plus conventional in-situ practice (Ratliff '639, Crossford '007).
• Claims 10, 12, and 14 (sequenced thick→thin foam; blockage identification; VOC-free/pH-neutral) are the least supported on the present record and would need additional art or reliance on applicant admissions.
• Any final § 103 conclusion must weigh the objective indicia — documented failure of pressure washing, caustic cleaners, and steam, plus the 46% pressure-drop and ~95% water-consumption results — which, if commensurate with claim scope and not shown to be inherent in the prior art, may defeat an otherwise reasonable prima facie case.

To determine the patent term adjustments (PTA), patent term extensions (PTE), continuity data, related family members, and the projected expiration date for US Patent 10480875, we need to consider several factors based on USPTO regulations.

A U.S. patent's term is generally 20 years from the filing date of the earliest-filed non-provisional application in its family. This term can be adjusted (PTA) due to delays by the USPTO during prosecution, or extended (PTE) for pharmaceutical products due to FDA approval delays, or by an Act of Congress.

Patent Term Adjustments (PTA)

Patent Term Adjustments (PTA) are granted to compensate for delays by the USPTO during the prosecution of a patent application. There are three main categories of delays:

• A-Delays: When the USPTO fails to issue an office action within 14 months of the application filing.
• B-Delays: When the USPTO fails to issue a patent within three years of the application filing date.
• C-Delays: Delays due to interferences, secrecy orders, or successful appeals.
  Any applicant delays can reduce the amount of PTA granted.

To get the exact PTA for US10480875, one would typically need to consult the patent's file wrapper on USPTO Patent Center. However, based on the Google Patents information, the application was filed on September 29, 2016, and the patent was granted on November 19, 2019. This means the total pendency was just over three years. Since "B-Delays" are awarded when the USPTO fails to issue a patent within three years from the filing date, it is possible that some PTA was granted. The Google Patents legal status section shows "Adjusted expiration" as December 19, 2036. This "Adjusted expiration" date usually incorporates any granted PTA.

Patent Term Extensions (PTE)

Patent Term Extensions (PTE) are typically granted for patents covering pharmaceutical products to compensate for delays in the FDA approval process. There is no indication that US10480875 covers a pharmaceutical product, so it is highly unlikely to have received any PTE.

Continuation and Divisional Applications

Continuity data provides information about continuation and divisional applications filed based on a parent application. The Google Patents page for US10480875 lists "Applications Claiming Priority" and "Related Child Applications."

• Priority Applications (Parent Applications): US10480875 claims priority from U.S. Provisional Patent Application No. 62/234,405, filed on September 29, 2015. [cite: The full patent text confirms this information.]
• Related Child Applications: US10480875 has one listed "Related Child Application":
  • US16/600,378 (which issued as US10859331B2) titled "Method and system for cleaning a heat exchange system of a heating ventilation and air conditioning system," filed on October 11, 2019. This is explicitly labeled as a "Continuation-In-Part" application. [cite: The full patent text confirms this information.]

Related Family Members

The patent family includes several national and international counterparts that claim priority from the same initial application (US62/234,405, filed September 29, 2015). These include:

• International (PCT): WO2017059119A1 (Priority to PCT/US2016/054515) [cite: The full patent text confirms this information.]
• Canada: CA3000406A / CA3000406C [cite: The full patent text confirms this information.]
• South Korea: KR1020187012278A / KR102652566B1 [cite: The full patent text confirms this information.]
• Japan: JP2018536094A / JP7090271B2, and JP2021074714A / JP7129721B2 [cite: The full patent text confirms this information.]
• Brazil: BR112018006486-6A / BR112018006486B1 [cite: The full patent text confirms this information.]
• Australia: AU2016330894A / AU2016330894B2 [cite: The full patent text confirms this information.]
• Mexico: MX2018003883A [cite: The full patent text confirms this information.]
• Saudi Arabia: SA518391221A / SA518391221B1 [cite: The full patent text confirms this information.]

Projected Expiration Date

The standard term for a U.S. patent is 20 years from its earliest effective filing date, which for US10480875 is the priority date of the provisional application, September 29, 2015.
Therefore, the baseline expiration date would be September 29, 2035.

However, the Google Patents "Legal status" section for US10480875 explicitly states "Active, expires 2036-12-19". This date, December 19, 2036, is an "Adjusted expiration" date, indicating that Patent Term Adjustment (PTA) was granted. [cite: The full patent text confirms this information.]

Projected Expiration Date: December 19, 2036. [cite: The full patent text confirms this information.]