DCT
2:17-cv-04077
Semco v. Trane US Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Semco, LLC (Missouri)
- Defendant: Trane U.S., Inc. (Delaware)
- Plaintiff’s Counsel: Polster, Lieder, Woodruff & Lucchesi, LC
- Case Identification: 2:17-cv-04077, W.D. Mo., 11/16/2017
- Venue Allegations: Plaintiff alleges venue is proper because Defendant has a regular and established place of business in the district and has committed acts of infringement there, including a specific sale of an accused system. Plaintiff further notes that Defendant previously indicated it would not challenge venue.
- Core Dispute: Plaintiff alleges that Defendant’s commercial HVAC systems infringe a patent related to an energy-efficient system and method for controlling both temperature and humidity.
- Technical Context: The technology concerns large-scale HVAC systems designed to provide significant amounts of dehumidified outdoor air, a critical function for maintaining air quality and occupant health in facilities like schools and hospitals.
- Key Procedural History: The complaint alleges a long history of interaction between the parties, including a dispute in 2005 and notice letters sent in 2010 and 2012. It also references a 2012 consent judgment from a separate case involving different defendants, where the patent-in-suit was found valid and infringed. Subsequent to the filing of this complaint, the patent-in-suit underwent an Inter Partes Review (IPR) at the U.S. Patent and Trademark Office, which resulted in the cancellation of all claims asserted in this litigation.
Case Timeline
| Date | Event |
|---|---|
| 1999-03-10 | '388 Patent Priority Date |
| 2001-03-13 | '388 Patent Issue Date |
| 2005-04-22 | Earliest alleged date of Defendant's knowledge of '388 Patent |
| 2010-02-18 | Plaintiff's counsel sends notice letter to Defendant |
| 2012-02-21 | Consent Judgment in SEMCO v. Huntair finds '388 Patent valid and infringed |
| 2013-01-01 | Alleged offer for sale/installation of accused system (Hoover Elementary) |
| 2016-01-01 | Alleged offer for sale/installation of accused system (Sioux Falls City Hall) |
| 2017-01-01 | Alleged offer for sale/installation of accused system (Bryant Elementary) |
| 2017-11-16 | First Amended Complaint Filing Date |
| 2021-01-12 | U.S. Patent Office issues Inter Partes Review Certificate cancelling Asserted Claim 1 |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 6,199,388 - "System And Method For Controlling Temperature And Humidity"
The Invention Explained
- Problem Addressed: The patent describes the difficulty conventional HVAC systems have in effectively and efficiently controlling humidity, particularly in buildings that require high volumes of fresh outdoor air, such as schools. This can lead to poor indoor air quality and microbial growth. Existing advanced systems were described as either limited in their dehumidification capability or reliant on complex, energy-intensive external heat sources to regenerate their desiccant materials. (’388 Patent, col. 1:12-2:32; col. 5:32-48).
- The Patented Solution: The invention proposes a system comprising two rotating wheels—a total energy recovery device and a dehumidification wheel—with a cooling coil positioned between them in the supply air stream. In this configuration, incoming fresh air is first pre-cooled and dehumidified by the energy recovery wheel, further cooled by the cooling coil, and then reheated and deeply dehumidified by the second wheel. The system is designed to be "passively" regenerated by the building's exhaust air, eliminating the need for an external heat source. (’388 Patent, Abstract; Fig. 3A; col. 8:23-46).
- Technical Importance: This design claimed to offer an energy-efficient method for achieving the very low humidity levels required by modern building standards, while using conventional cooling equipment and providing flexible control over both temperature and humidity. (’388 Patent, col. 5:26-31; col. 6:11-20).
Key Claims at a Glance
- The complaint asserts independent Claim 1. (Compl. ¶13).
- The essential elements of Claim 1 are:
- an air supplier adapted to supply air to the controlled space, creating a supply air stream;
- an air exhauster adapted to exhaust air out of the controlled space, creating an exhaust air stream adjacent to the supply air stream;
- a partition disposed between the supply and exhaust air streams that separates the supply and exhaust air streams;
- a total energy recovery device in contact with the supply air stream and exhaust air stream that exchanges heat and moisture between the supply and exhaust air streams;
- a dehumidification wheel positioned to rotate through the supply air stream and the exhaust air stream that exchanges heat and moisture between the supply and exhaust air streams; and
- a cooler disposed in the supply air stream between the total energy recovery device and the dehumidification wheel, the cooler adapted to cool and dehumidify the supply air stream.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
The complaint accuses certain Trane air handling systems, identifying specific installations at Sioux Falls City Hall, the University of Sioux Falls, Hoover Elementary School, Bryant Elementary School, and Adams Elementary School. (Compl. ¶¶8-12).
Functionality and Market Context
The accused products are described as commercial HVAC systems, which Trane allegedly classifies as having a "dual path, outside air configuration" containing both an "energy wheel and CDQ wheel." (Compl. ¶42). The complaint alleges these systems incorporate all the structural components of Claim 1 in the same sequence: an air supplier (fan), an air exhauster (fan), a partition, a total energy recovery device (Trane's "Energy wheel"), a dehumidification wheel (Trane's "CDQ wheel"), and a cooler ("Cooling coil") positioned between the two wheels. (Compl. ¶¶13-21). For example, the complaint describes a drawing from its Exhibit 2 depicting the accused system’s "Overall Elevation View" with labeled components corresponding to the claimed elements. (Compl. ¶15).
IV. Analysis of Infringement Allegations
'388 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| an air supplier adapted to supply air to the controlled space, creating a supply air stream | The accused systems contain air suppliers, depicted as fans, that supply air to a controlled space. | ¶14 | col. 8:25-27 |
| an air exhauster adapted to exhaust air out of the controlled space, creating an exhaust air stream adjacent to the supply air stream | The accused systems contain air exhausters, also depicted as fans, that exhaust air from the controlled space. | ¶14 | col. 8:27-29 |
| a partition disposed between the supply and exhaust air streams that separates the supply and exhaust air streams | The accused systems' drawings allegedly depict a partition separating the supply and exhaust fans and their respective air paths. | ¶15 | col. 8:29-32 |
| a total energy recovery device in contact with the supply air stream and exhaust air stream that exchanges heat and moisture... | The accused systems contain a device referred to as an "Energy wheel" that rotates through both the supply and exhaust air paths to exchange heat and moisture. | ¶16 | col. 8:32-37 |
| a dehumidification wheel positioned to rotate through the supply air stream and the exhaust air stream that exchanges heat and moisture... | The accused systems contain a device referred to as a "CDQ wheel," which is alleged to be a desiccant wheel for humidity control that rotates through both air paths. | ¶¶18-19 | col. 8:37-41 |
| a cooler disposed in the supply air stream between the total energy recovery device and the dehumidification wheel... adapted to cool and dehumidify the supply air stream | The accused systems contain a "Cooling coil" allegedly positioned in the supply air stream between the "Energy wheel" and the "CDQ wheel." | ¶21 | col. 8:41-46 |
- Identified Points of Contention:
- Legal/Procedural Question: A threshold question, arising from events subsequent to the complaint's filing, is the legal status of the case given that an Inter Partes Review certificate cancelled Claim 1, the sole claim asserted.
- Technical Question: Assuming the claim were valid, a key technical dispute would focus on whether Trane's "CDQ wheel" performs the specific function of the claimed "dehumidification wheel." The complaint alleges the "CDQ wheel" is for humidity control (Compl. ¶19), but the patent describes specific properties for its wheel, such as being passively regenerated and having a high ratio of desiccant mass to substrate mass. (’388 Patent, col. 10:40-45, 65-68). The court would need to determine if Trane's component meets these more specific, functional descriptions from the patent's specification.
V. Key Claim Terms for Construction
- The Term: "dehumidification wheel"
- Context and Importance: This term is at the heart of the invention and the infringement allegation. Its construction will determine whether Trane's "CDQ wheel" falls within the scope of the claims. Practitioners may focus on this term because the patent's specification imbues it with characteristics beyond a generic heat and moisture exchange wheel, which may be a basis for a non-infringement defense.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language of Claim 1 only requires that the wheel be "positioned to rotate through the supply air stream and the exhaust air stream" and that it "exchanges heat and moisture." (’388 Patent, col. 19:55-60).
- Evidence for a Narrower Interpretation: The specification describes the preferred dehumidification wheel as a "passive desiccant-based wheel that does not require any additional high temperature regeneration energy" (’388 Patent, col. 10:40-45) and as being distinct from a total energy recovery wheel by having "relatively more desiccant mass (50%-70%)" (’388 Patent, col. 10:67-col. 11:1).
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement, asserting that Trane personnel provided customers with design software, performance data, and specific configuration information, with full knowledge that the resulting systems would infringe the ’388 Patent. (Compl. ¶¶54-55). It is also alleged that Trane encouraged continued use of the systems post-sale. (Compl. ¶56).
- Willful Infringement: The complaint alleges a long history of pre-suit knowledge to support willfulness. The allegations include a 2005 interaction where a Trane employee acknowledged the patent (Compl. ¶45), a 2010 notice letter from Plaintiff’s counsel (Compl. ¶46), and a 2012 letter that included a copy of a consent judgment from a separate case where the ’388 Patent was found valid and infringed by similar systems. (Compl. ¶¶47-49).
VII. Analyst’s Conclusion: Key Questions for the Case
- The paramount question, arising post-filing, is one of case viability: what is the legal effect of the U.S. Patent and Trademark Office’s Inter Partes Review decision cancelling Claim 1, the sole claim asserted as infringed in the complaint?
- Should the case proceed, a central issue would be one of claim construction: can the term "dehumidification wheel," as defined by the patent’s detailed specification, be construed to read on the accused "CDQ wheel," particularly concerning the passive regeneration and material composition characteristics described as integral to the invention?
- A key evidentiary question would concern willfulness: considering the extensive history of communications alleged in the complaint, what evidence exists to establish Trane's state of mind regarding potential infringement and the patent’s validity during the accused period?