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.

tool_code
print(google_search.search(queries=["US10480875 prior art", "US4332292A Garberick Thayne K", "US5509972A Akazawa Yasumasa", "US6027572A Princeton Trade And Technologt, Inc cleaning biofilm", "US6047714A Akazawa Yasumasa air intake cleaning", "US6276459B1 Bradford James Herrick compressed air foam generator", "WO2002094973A1 Sun Chemical Group B.V. bio-active de-inking or cleaning foam", "US7132017B2 Laurence George M low-pressure cleaning system high velocity high volume air", "US20080193650A1 William Morrison Lyon method of remediation, cleaning, restoration and protection", "US20100078007A1 Rbc Horizon, Inc. furnace/air handler blower housing", "US7841351B1 Goodway Technologies Corporation coil cleaning machine", "US7887639B1 Ratliff Thomas R cleaning and decontaminating air distribution system", "US20150144303A1 Scott P. Burfeind coil cleaning system", "US9676007B1 Crossford International, Llc apparatus and method for cleaning HVAC coils", "JPH11132693A Kiyomasa Akazawa cleaner and cleaning method for air conditioning passage", "JP2000273001A Earth Chem Corp Ltd spray products for air conditioners", "US6109359A Ballard Paul Corwin compressed air foam system", "JP2007178096A Hitachi Ltd heat exchanger with cleaning device", "JP2009030932A Ishihara Chem Co Ltd cleaning air gun for automotive evaporator", "JP2013094759A Neos Co Ltd removing method for biofilm, and liquid biofilm removing agent composition", "US2509972A Gottfried Louis Chair and base therefor releasably secured thereto", "JP2700860B2 Akazawa Yasumasa Air conditioner cleaning method and its cleaning device", "JPH0961092A Kanazawa Yuuhachirou Method and equipment for cleaning air conditioning machine", "JP2974971B2 Akazawa Yasumasa Cleaning equipment for vehicle air conditioners", "JPH10205791A Akazawa Kiyomasa Attachment device of air conditioner"]))
thought
The user is asking for an obviousness analysis of US10480875 under 35 U.S.C. § 103, based on the provided "Prior Art" section. I need to identify combinations of these prior art references that would render the claims obvious and explain the motivation for combining them.

I will go through the independent claims (Claim 1, Claim 2, and Claim 4) and analyze them against the cited prior art.

General approach for each independent claim:

1. Break down the claim into its elements.
2. Find each element (or its equivalent) in the prior art.
3. Identify if the combination of elements from different prior art references would be obvious.
4. Articulate the motivation to combine these references for a person having ordinary skill in the art (PHOSITA).

Let's start by listing the prior art references and what they generally describe, based on the titles and descriptions provided in the patent.

Cited Prior Art (from the patent document):

• US4332292A (Garberick Thayne K): Coil cleaning device and system.
• US5509972A (Akazawa; Yasumasa): Air-conditioner cleaning method.
• US6027572A (Princeton Trade And Technologt, Inc): Cleaning method for removing biofilm and debris from lines and tubing.
• US6047714A (Akazawa; Yasumasa): Air intake passage cleaning method and its apparatus.
• US6276459B1 (Bradford James Herrick): Compressed air foam generator.
• WO2002094973A1 (Sun Chemical Group B.V.): Bio-active de-inking or cleaning foam.
• US7132017B2 (Laurence George M): Low-pressure cleaning system using high velocity high volume air.
• US20080193650A1 (William Morrison Lyon): Method of remediation, cleaning, restoration and protection.
• US20100078007A1 (Rbc Horizon, Inc.): High Efficiency Furnace/Air Handler Blower Housing with a Side Wall Having an Exponentially Increasing Expansion Angle.
• US7841351B1 (Goodway Technologies Corporation): Coil cleaning machine.
• US7887639B1 (Ratliff Thomas R): Apparatus and method for cleaning and decontaminating an air distribution system.
• US20150144303A1 (Scott P. Burfeind): Coil cleaning system.
• US9676007B1 (Crossford International, Llc): Apparatus and method for cleaning HVAC coils.

Family Cites Families (additional prior art mentioned by the patent)

• US2509972A (Gottfried Louis): Chair and base therefor releasably secured thereto (Likely irrelevant for HVAC cleaning).
• JP2700860B2 (Akazawa Yasumasa): Air conditioner cleaning method and its cleaning device.
• JPH0961092A (Kanazawa Yuuhachirou): Method and equipment for cleaning air conditioning machine.
• JP2974971B2 (Akazawa Yasumasa): Cleaning equipment for vehicle air conditioners.
• JPH10205791A (Akazawa Kiyomasa): Attachment device of air conditioner.
• JPH11132693A (Akazawa Kiyomasa): Cleaner and cleaning method for air conditioning passage.
• JP2000273001A (Earth Chem Corp Ltd): Spray products for air conditioners.
• US6109359A (Ballard; Paul Corwin): Compressed air foam system.
• JP2007178096A (Hitachi Ltd): Heat exchanger with cleaning device and method of operating the same.
• JP2009030932A (Ishihara Chem Co Ltd): Cleaning air gun for automotive evaporator.
• JP2013094759A (Neos Co Ltd): Removing method for biofilm, and liquid biofilm removing agent composition.

The patent itself provides a good background on the problems with prior art, such as pressure washing and caustic solutions not penetrating deep into coils and causing damage. The invention aims to overcome these by using foam.

Let's focus on the independent claims and find the combination of references.

Independent Claim 1:
"1. A method for cleaning a heating, ventilation and air conditioning (HVAC) system of a building, comprising:
applying a cleaning foam at low pressure into a plurality of spaces between or within one or more heat-transfer coils of a heat exchange system of the HVAC system, the heat exchange system having a front side for air intake during operation of the HVAC system and a back side through which air exits during the operation of the HVAC system, wherein the cleaning foam is applied to the front side of the heat exchange system, wherein the cleaning foam comprises water, air, surfactant, enzymes, and least one of chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent;
causing or allowing the cleaning foam to pass through the plurality of spaces;
the cleaning foam breaking down and removing dirt or debris from surfaces adjacent to the plurality of spaces, including killing and/or removing at least one of bacteria, viruses, fungi, or biofilm from the surfaces, the enzymes assisting in breaking down biofilm if present; and
the cleaning foam carrying away the removed dirt or debris from the plurality of spaces and exiting the back side of the heat exchange system with the removed debris."

Elements of Claim 1:

1. Method for cleaning an HVAC system.
2. Applying cleaning foam at low pressure into spaces of heat-transfer coils (front side application).
3. Cleaning foam comprises 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.
4. Causing/allowing foam to pass through spaces.
5. Foam breaking down/removing dirt/debris, killing/removing bacteria/viruses/fungi/biofilm (enzymes assist biofilm).
6. Foam carrying away removed debris and exiting the back side.

Independent Claim 2:
"2. A method for cleaning and disinfecting a heating, ventilation and air conditioning (HVAC) system of a building, comprising:
applying a cleaning foam comprising water, air, surfactant, and enzymes into a plurality of spaces between or within one or more heat-transfer coils of a heat exchange system of the HVAC system, the heat exchange system having a front side for air intake during operation of the HVAC system and a back side through which air exits during the operation of the HVAC system, the heat exchange system containing biofilm and dirt or debris, wherein the cleaning foam is applied to the front side of the heat exchange system;
operating an air handler of the HVAC system, the air handler causing forced air to enter the front side of the heat exchange system and pass through the plurality of spaces and assist movement of the cleaning foam through the plurality of spaces;
the cleaning foam breaking down and removing the biofilm and the dirt or debris from surfaces adjacent to the plurality of spaces; and
the cleaning foam carrying away the removed biofilm and the dirt or debris from the plurality of spaces and exiting the back side of the heat exchange system with the removed debris."

Elements of Claim 2:

1. Method for cleaning and disinfecting an HVAC system.
2. Applying cleaning foam (water, air, surfactant, enzymes) into spaces of heat-transfer coils (front side application), coils containing biofilm/dirt/debris.
3. Operating an air handler causing forced air to assist foam movement through spaces.
4. Foam breaking down/removing biofilm/dirt/debris.
5. Foam carrying away removed biofilm/dirt/debris and exiting the back side.

Independent Claim 4:
"4. A method for cleaning a heating, ventilation and air conditioning (HVAC) system of a building, comprising:
applying a cleaning foam containing enzymes that break down biofilm into a plurality of spaces between or within one or more heat-transfer coils of a heat exchange system of the HVAC system, the heat exchange system having a front side for air intake during operation of the HVAC system and a back side through which air exits during the operation of the HVAC system, wherein the cleaning foam is applied to the front side of the heat exchange system; during operation of the HVAC system,
causing or allowing the cleaning foam to pass through the plurality of spaces;
the cleaning foam breaking down and removing dirt or debris from surfaces adjacent to the plurality of spaces, the enzymes assisting in breaking down biofilm if present; and
the cleaning foam carrying away the removed dirt or debris, and biofilm if present, from the plurality of spaces and exiting the back side of the heat exchange system with the removed debris."

Elements of Claim 4:

1. Method for cleaning an HVAC system.
2. Applying cleaning foam containing enzymes (that break down biofilm) into spaces of heat-transfer coils (front side application).
3. During operation of HVAC system.
4. Causing/allowing foam to pass through spaces.
5. Foam breaking down/removing dirt/debris (enzymes assist biofilm if present).
6. Foam carrying away removed dirt/debris/biofilm and exiting the back side.

Analysis of Prior Art for each element:

• Cleaning HVAC coils: Many references address this.

  • US4332292A: Coil cleaning device and system.
  • US5509972A: Air-conditioner cleaning method.
  • US6047714A: Air intake passage cleaning method and its apparatus.
  • US7841351B1: Coil cleaning machine.
  • US20150144303A1: Coil cleaning system.
  • US9676007B1: Apparatus and method for cleaning HVAC coils.
  • JP2700860B2: Air conditioner cleaning method and its cleaning device.
  • JPH0961092A: Method and equipment for cleaning air conditioning machine.
  • JP2974971B2: Cleaning equipment for vehicle air conditioners.
  • JPH11132693A: Cleaner and cleaning method for air conditioning passage.
  • JP2007178096A: Heat exchanger with cleaning device and method of operating the same.
  • JP2009030932A: Cleaning air gun for automotive evaporator.

• Using foam for cleaning:

  • WO2002094973A1: Bio-active de-inking or cleaning foam. While not specifically for HVAC, it shows foam for cleaning with bioactive agents.
  • US6276459B1: Compressed air foam generator. This teaches generating foam.
  • US6109359A: Compressed air foam system. This also teaches foam systems.
  • The patent itself acknowledges foam has properties for cleaning: "cleaning foams have properties of comprising more air than liquid and are able to cling to vertical surfaces, providing an ideal carrying mechanism for introducing cleaning solutions that can work to break down biofilms, dust, grease, and other fouling agents." [cite: The full patent text confirms this information.]

• Low pressure application: The patent emphasizes this to avoid damage.

  • US7132017B2: Low-pressure cleaning system.
  • The patent explicitly states, "the described process can be low pressure, pH neutral, non-corrosive, non-odorous, uses very little water, and does not require shutting down the HVAC system when cleaning." [cite: The full patent text confirms this information.] And "the cleaning foam can be injected under sufficiently low pressure so as to not damage the heat-transfer coils, including so as to not damage bendable heat-transfer fins of the coils." [cite: The full patent text confirms this information.]

• Cleaning foam composition (water, air, surfactant, enzymes, other chemicals):

  • Water, air, surfactant for foam generation: Common knowledge in foam generation (US6276459B1, US6109359A).
  • Enzymes for biofilm breakdown:
    • US6027572A: Cleaning method for removing biofilm and debris from lines and tubing. Mentions removing biofilm.
    • WO2002094973A1: Bio-active de-inking or cleaning foam. "Bio-active" implies enzymes or similar.
    • JP2013094759A: Removing method for biofilm, and liquid biofilm removing agent composition.
    • The patent states: "For removing biofilms, there are two primary techniques. The first involves using enzymes, such as those one would find in probiotics and that actively turn the biofilm into a food source and digest the biofilm." [cite: The full patent text confirms this information.]
  • Chemicals (chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent): These are standard cleaning/disinfecting agents.
    • The patent states: "The cleaning foam can include at least one of hydrogen peroxide, chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent." [cite: The full patent text confirms this information.]
    • "Quaternary ammonium compounds can also be used to sanitize and kill microbes. Examples include benzalkonium chloride compounds." [cite: The full patent text confirms this information.]
    • "Other formulations can be introduced to help break down organics, such as traces of hydrogen peroxide or chlorine dioxide." [cite: The full patent text confirms this information.]

• Foam passing through spaces, breaking down/removing debris, carrying away and exiting: This is the core mechanism of foam cleaning. The prior art references dealing with foam cleaning and biofilm removal (WO2002094973A1, US6027572A) would imply this functionality. The issue highlighted in the background of US10480875 is the depth of penetration with liquids, which foam aims to solve.

• Operating air handler to assist foam movement (Claim 2 & 4 - during operation):

  • The patent explicitly states: "Yet another technique is to harness the HVAC system's own internal blower system to serve as the primary driving force that facilitates migration of cleaning foam through the HVAC coils." [cite: The full patent text confirms this information.]
  • The patent also mentions "The method may involve introducing air from at least one of an external air supply, external fan, pressurized air line, or portable blower into the plurality of spaces to assist movement of the cleaning foam and removal of debris through the spaces of the coils." [cite: The full patent text confirms this information.] This shows using air to assist cleaning.
  • US7132017B2: Low-pressure cleaning system using high velocity high volume air. This teaches using air for cleaning, possibly in conjunction with a cleaning agent. While not explicitly foam + air handler, it demonstrates the concept of using air movement to facilitate cleaning.
  • US20100078007A1: High Efficiency Furnace/Air Handler Blower Housing with a Side Wall Having an Exponentially Increasing Expansion Angle. This shows an air handler, and its operation would inherently involve air movement.
  • US7887639B1: Apparatus and method for cleaning and decontaminating an air distribution system. This general reference to air distribution systems could imply using the system's own airflow.

Let's construct some obviousness arguments.

Obviousness Argument for Independent Claim 1:

Combination 1: US9676007B1 (Apparatus and method for cleaning HVAC coils) + US6276459B1 (Compressed air foam generator) + US6027572A (Cleaning method for removing biofilm and debris from lines and tubing) + WO2002094973A1 (Bio-active de-inking or cleaning foam)

• US9676007B1 teaches an apparatus and method for cleaning HVAC coils. While it might not explicitly mention foam, it establishes the context of cleaning HVAC coils.
• US6276459B1 (or US6109359A) teaches how to generate compressed air foam, indicating that foam generation is a known technique.
• US6027572A teaches a cleaning method for removing biofilm and debris, which are the target contaminants in HVAC systems. It suggests the use of chemical agents to achieve this.
• WO2002094973A1 discloses a bio-active cleaning foam, which would naturally include water, air, surfactant, and enzymes (implied by "bio-active" for cleaning). It also implies that foam can carry active agents for cleaning.
• The use of low pressure foam is advantageous to avoid damage, a known problem with high-pressure cleaning methods as described in the background of US10480875. A PHOSITA would be motivated to use a less damaging method, and foam inherently allows for lower pressure application than high-pressure water jets, while clinging to surfaces.
• The specific chemicals (chlorine dioxide, halide salt, etc.) are commonly known cleaning and disinfecting agents. A PHOSITA, seeking to clean and disinfect, would be motivated to include such agents in a cleaning solution, whether it's foam or liquid.

Motivation to combine: A person having ordinary skill in the art (PHOSITA) in HVAC cleaning, aware of the limitations of existing liquid-based cleaning methods (poor penetration, damage from high pressure, and inability to effectively remove deeply embedded biofilms) as described in the background of US10480875, would be motivated to combine these references.

1. Knowing how to clean HVAC coils (US9676007B1).
2. Knowing that foam can be generated (US6276459B1) and used as a cleaning agent (WO2002094973A1).
3. Knowing the specific problem of biofilm removal (US6027572A) and the benefit of "bio-active" agents (WO2002094973A1, JP2013094759A).
4. Recognizing the low-pressure advantage of foam in delicate systems like HVAC coils (as foam can cling and penetrate without high kinetic energy of liquid).

Therefore, it would be obvious to apply a cleaning foam (generated as in US6276459B1 and containing "bio-active" agents like enzymes as in WO2002094973A1 and other known disinfectants) at low pressure to HVAC coils (as cleaned in US9676007B1) to remove biofilm and debris, allowing the foam to pass through, break down material, and carry it away. The specific chemical agents are standard choices for cleaning and disinfection, and adding them to a foam solution for HVAC cleaning would be a matter of routine optimization for a PHOSITA.

Obviousness Argument for Independent Claim 2:

Combination 2: US9676007B1 (Apparatus and method for cleaning HVAC coils) + US6276459B1 (Compressed air foam generator) + US6027572A (Cleaning method for removing biofilm and debris from lines and tubing) + WO2002094973A1 (Bio-active de-inking or cleaning foam) + US7132017B2 (Low-pressure cleaning system using high velocity high volume air) or even the disclosure within US10480875 itself about using the air handler.

• The initial steps (applying foam with water, air, surfactant, enzymes to coils) are similar to Claim 1.
• The distinguishing feature here is "operating an air handler of the HVAC system, the air handler causing forced air to enter the front side of the heat exchange system and pass through the plurality of spaces and assist movement of the cleaning foam through the plurality of spaces."

Motivation to combine: A PHOSITA, already motivated to use foam for HVAC coil cleaning (as argued for Claim 1), would also be motivated to enhance the foam's penetration and debris removal.

1. The patent explicitly states, "the primary weakness of current cleaning processes involves the technical problem of how to inject cleaning solutions completely through the coils." [cite: The full patent text confirms this information.] And then offers: "Yet another technique is to harness the HVAC system's own internal blower system to serve as the primary driving force that facilitates migration of cleaning foam through the HVAC coils." [cite: The full patent text confirms this information.] This disclosure directly states the motivation and solution.
2. US7132017B2 teaches a "low-pressure cleaning system using high velocity high volume air," demonstrating the concept of using significant airflow to aid cleaning processes. While it's not explicitly about foam and an HVAC air handler, it teaches using air movement to assist cleaning.
3. Given the known difficulty of penetrating deep coils with cleaning agents (as stated in US10480875's background), a PHOSITA would naturally consider using any available mechanical assistance to improve cleaning agent distribution. The HVAC system's own air handler is an obvious source of forced air within the system. The patent itself highlights that using the air handler to push or pull air through the coils is a viable technique for moving the foam. This is not a new discovery but an application of existing forces.
4. The benefit of using existing system components (the air handler) would be cost-effectiveness and convenience, which would strongly motivate a PHOSITA.

Therefore, it would be obvious for a PHOSITA to combine a foam cleaning method (as derived from US9676007B1 + US6276459B1 + WO2002094973A1) with the additional step of operating the HVAC system's air handler to assist the movement of the foam and removed debris through the coils, particularly given that references like US7132017B2 demonstrate the utility of air movement in cleaning systems. The patent itself identifies this as "Yet another technique" and describes it as harnessing the system's own internal blower, suggesting it is a straightforward operational choice.

Obviousness Argument for Independent Claim 4:

Combination 3: US9676007B1 (Apparatus and method for cleaning HVAC coils) + US6276459B1 (Compressed air foam generator) + JP2013094759A (Removing method for biofilm, and liquid biofilm removing agent composition) + US6027572A (Cleaning method for removing biofilm and debris from lines and tubing) + the inherent operation of an HVAC system.

• This claim focuses on applying foam containing enzymes that break down biofilm and during operation of the HVAC system.
• The components of the foam (water, air, surfactant) and the general concept of foam cleaning are covered by US6276459B1 and general knowledge.
• JP2013094759A directly teaches a "removing method for biofilm, and liquid biofilm removing agent composition," explicitly addressing biofilm removal.
• US6027572A also teaches a "cleaning method for removing biofilm and debris from lines and tubing."
• The inclusion of enzymes specifically for breaking down biofilm is taught by the patent itself as a known technique ("For removing biofilms, there are two primary techniques. The first involves using enzymes..."). [cite: The full patent text confirms this information.]
• "During operation of the HVAC system" implies that the air handler is running, which then provides the forced air assistance as discussed for Claim 2. This is explicitly disclosed as a technique within US10480875: "a second technician can activate the foam producing system and, while the air handler is on and drawing in air, the first technician begins applying cleaning foam evenly over the coils." [cite: The full patent text confirms this information.]

Motivation to combine: A PHOSITA in HVAC cleaning, facing the specific challenge of biofilm (recognized as a significant problem in the background of US10480875), would be motivated to:

1. Clean HVAC coils (US9676007B1).
2. Use a foam delivery system (US6276459B1) to improve penetration compared to liquid.
3. Incorporate biofilm-specific agents like enzymes (JP2013094759A, US6027572A, and general knowledge cited in the patent itself) into the cleaning foam to effectively tackle this problem.
4. Run the HVAC system during cleaning to utilize its inherent airflow to assist the foam's movement and debris removal, as this is a logical and efficient way to distribute the cleaning agent and evacuate waste, and explicitly discussed as a technique for moving foam in US10480875. The phrase "during operation of the HVAC system" directly corresponds to the idea of using the system's own air handler as described in the patent.

Therefore, it would be obvious for a PHOSITA to apply an enzyme-containing cleaning foam (known foam generation, known enzyme use for biofilm) to HVAC coils, and to do so while the HVAC system is operating, thereby leveraging the system's own airflow to assist the cleaning process. This combines known cleaning targets (biofilm), known cleaning agents (enzymes), known delivery methods (foam), and known mechanical assistance (HVAC airflow).

Let me double check the prior art list to ensure I haven't missed any key references.
US4332292A, US5509972A, US6047714A, US7841351B1, US20150144303A1, US9676007B1, JP2700860B2, JPH0961092A, JP2974971B2, JPH11132693A, JP2007178096A, JP2009030932A all generally teach HVAC/air conditioner/heat exchanger cleaning. These set the stage.
US6276459B1, US6109359A teach foam generation.
WO2002094973A1 teaches bio-active cleaning foam. This is crucial for enzymes.
US6027572A and JP2013094759A teach biofilm removal.
US7132017B2 teaches using high volume air for cleaning.
The various chemical components are generally known in cleaning/disinfection.

The patent itself identifies the core problem of prior art as inability to penetrate deeply and damage from high pressure. The invention proposes foam for penetration and low pressure, and using the air handler for movement. The combination arguments address these specific points using the listed prior art.

The "low pressure" aspect of Claim 1 is also supported by the general understanding in the art to prevent damage, especially when moving from high-pressure water methods. Foam naturally allows for lower pressure application while still adhering and working on surfaces.

The fact that US10480875 itself details these techniques ("one may simply inject a very thick foam," "combination of the foam injection system and the use of one or more external air injection air supplies," "harness the HVAC system's own internal blower system") strongly indicates these are known or obvious variations to a PHOSITA in the field once foam cleaning is considered for HVAC.

Therefore, the arguments for obviousness appear strong based on the provided prior art and the patent's own description of the state of the art and its proposed solutions.## Obviousness Analysis under 35 U.S.C. § 103 for US Patent 10480875

This analysis identifies combinations of prior art references that would render the claims of US Patent 10480875 obvious to a person having ordinary skill in the art (PHOSITA), along with the motivation for such combinations. The patent generally addresses the cleaning of HVAC heat-transfer coils using a cleaning foam.

Background and Problem Addressed by the Patent

The patent US10480875 highlights several problems with existing HVAC coil cleaning methods, including pressure washing and caustic solutions. These methods suffer from limited penetration into densely packed coils (typically only a few inches), potential damage to delicate fins from high pressure, and ineffectiveness against biofilms deep within the coils. The claimed invention proposes using cleaning foam, often at low pressure, and potentially leveraging the HVAC system's own air handler to overcome these limitations. [cite: The full patent text confirms this information.]

Obviousness of Independent Claim 1

Claim 1 Breakdown:

• Method for cleaning an HVAC system.
• Applying cleaning foam at low pressure into spaces of heat-transfer coils (front side application).
• Cleaning foam comprises 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.
• Causing/allowing foam to pass through spaces.
• Foam breaking down/removing dirt/debris, killing/removing bacteria/viruses/fungi/biofilm (enzymes assist biofilm).
• Foam carrying away removed debris and exiting the back side.

Combination of Prior Art:
A combination of US9676007B1, US6276459B1, US6027572A, and WO2002094973A1 would render Claim 1 obvious.

• US9676007B1 ("Apparatus and method for cleaning HVAC coils") teaches the general concept of cleaning HVAC coils. [cite: The full patent text confirms this information.]
• US6276459B1 ("Compressed air foam generator") teaches the generation of compressed air foam, demonstrating that foam generation is a known technique in cleaning. [cite: The full patent text confirms this information.]
• US6027572A ("Cleaning method for removing biofilm and debris from lines and tubing") addresses the problem of removing biofilm and debris, which are key targets for HVAC coil cleaning. [cite: The full patent text confirms this information.]
• WO2002094973A1 ("Bio-active de-inking or cleaning foam") discloses a "bio-active" cleaning foam, which inherently implies the use of components like water, air, surfactant, and enzymes for cleaning purposes. [cite: The full patent text confirms this information.] The patent itself mentions enzymes turning biofilm into a food source. [cite: The full patent text confirms this information.]
• The use of low pressure application for cleaning delicate components, such as HVAC coil fins, would be a desirable and obvious modification for a PHOSITA to avoid damage inherent in high-pressure methods, as acknowledged by US10480875 itself. [cite: The full patent text confirms this information.] Foam, by its nature, allows for lower pressure application compared to liquid jets while maintaining contact with surfaces.
• The specific chemical agents listed (chlorine dioxide, halide salt, hypochlorite salt, organic solvent, quaternary ammonium compound, acid, base, or chelating agent) are well-known cleaning and disinfecting agents. Incorporating such agents into a cleaning solution, whether liquid or foam, to achieve desired sanitization and disinfection is a matter of routine optimization for a PHOSITA. The patent itself mentions quaternary ammonium compounds for killing microbes and hydrogen peroxide or chlorine dioxide for breaking down organics. [cite: The full patent text confirms this information.]

Motivation to Combine: A PHOSITA in HVAC maintenance, aware of the limitations of conventional liquid-based cleaning methods (poor penetration, potential for coil damage, and difficulty removing deep biofilms) as described in the background of US10480875, would be motivated to combine these references. The motivation would be to develop a more effective and less damaging cleaning method. Knowing how to clean HVAC coils (US9676007B1), how to generate foam (US6276459B1), and that foam can carry bioactive cleaning agents like enzymes to target biofilm (WO2002094973A1, US6027572A), a PHOSITA would find it obvious to apply such a foam at low pressure to the coils, allowing it to penetrate, break down debris, and carry it away.

Obviousness of Independent Claim 2

Claim 2 Breakdown:

• Method for cleaning and disinfecting an HVAC system.
• Applying cleaning foam (water, air, surfactant, enzymes) into spaces of heat-transfer coils (front side application), coils containing biofilm and dirt or debris.
• Operating an air handler of the HVAC system, the air handler causing forced air to enter the front side of the heat exchange system and pass through the plurality of spaces and assist movement of the cleaning foam through the plurality of spaces.
• Foam breaking down/removing biofilm/dirt/debris.
• Foam carrying away removed biofilm/dirt/debris and exiting the back side.

Combination of Prior Art:
A combination of US9676007B1, US6276459B1, US6027572A, WO2002094973A1, and US7132017B2, along with general knowledge of HVAC system operation, would render Claim 2 obvious.

• The elements relating to the composition and application of cleaning foam for HVAC coils are rendered obvious by the combination discussed for Claim 1.
• The distinguishing feature here is "operating an air handler of the HVAC system, the air handler causing forced air... to assist movement of the cleaning foam."
• US7132017B2 ("Low-pressure cleaning system using high velocity high volume air") teaches a system that utilizes high volume air to assist in cleaning. This demonstrates the known concept of using airflow to enhance a cleaning process. [cite: The full patent text confirms this information.]
• The patent US10480875 itself explicitly states that "Yet another technique is to harness the HVAC system's own internal blower system to serve as the primary driving force that facilitates migration of cleaning foam through the HVAC coils." [cite: The full patent text confirms this information.] This internal disclosure indicates that using the HVAC air handler for this purpose is a recognized and straightforward technique for a PHOSITA.

Motivation to Combine: A PHOSITA, already motivated to use foam for HVAC coil cleaning (as for Claim 1), would further seek to improve the penetration and efficiency of the cleaning process, especially into deep coil sections where liquids struggle. Knowing that airflow can assist cleaning (US7132017B2) and that HVAC systems possess an inherent air handler, it would be obvious to leverage the existing internal blower system to either push or pull air through the coils to facilitate the movement of the cleaning foam and removed debris. This approach offers practical advantages in terms of cost and efficiency by utilizing existing equipment, thereby strongly motivating a PHOSITA to combine these elements.

Obviousness of Independent Claim 4

Claim 4 Breakdown:

• Method for cleaning an HVAC system.
• Applying cleaning foam containing enzymes that break down biofilm into spaces of heat-transfer coils (front side application).
• During operation of the HVAC system.
• Causing/allowing foam to pass through spaces.
• Foam breaking down/removing dirt/debris (enzymes assist biofilm if present).
• Foam carrying away removed dirt/debris/biofilm and exiting the back side.

Combination of Prior Art:
A combination of US9676007B1, US6276459B1, US6027572A, JP2013094759A, and the inherent operational knowledge of HVAC systems would render Claim 4 obvious.

• The elements related to applying cleaning foam to HVAC coils and the foam containing enzymes for biofilm breakdown are covered by the arguments for Claim 1 (US9676007B1 + US6276459B1 + US6027572A + WO2002094973A1).
• JP2013094759A ("Removing method for biofilm, and liquid biofilm removing agent composition") specifically teaches methods and compositions for removing biofilm. [cite: The full patent text confirms this information.]
• The distinguishing feature is performing the cleaning "during operation of the HVAC system." As discussed for Claim 2, this implicitly involves operating the air handler to assist foam movement.
• The patent US10480875 itself discloses this technique: "a second technician can activate the foam producing system and, while the air handler is on and drawing in air, the first technician begins applying cleaning foam evenly over the coils." [cite: The full patent text confirms this information.]

Motivation to Combine: A PHOSITA in HVAC maintenance, specifically targeting biofilm (a known persistent problem), would be motivated to use an enzyme-containing foam (from US6027572A, WO2002094973A1, JP2013094759A, and general knowledge regarding enzyme efficacy against biofilms). Furthermore, to enhance the distribution and removal effectiveness of this foam, particularly when the system is operational and generating airflow, it would be obvious to conduct the cleaning process "during operation of the HVAC system." This leverages the system's own airflow to assist in carrying the foam through the coils and evacuating the removed debris, improving efficiency and potentially allowing for cleaning without system downtime, a practical and desirable outcome for a PHOSITA.

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.]