DCT
0:21-cv-00619
Schwab Vollhaber Lubratt Inc v. Carson Design Mfg Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Schwab-Vollhaber-Lubratt, Inc. (Minnesota)
- Defendant: Carson Design and Manufacturing, Inc. d/b/a Carson Solutions and Midwest Mechanical Supply, Inc. d/b/a Midwest Mechanical Solutions (Minnesota)
- Plaintiff’s Counsel: Merchant & Gould P.C.
- Case Identification: 0:21-cv-00619, D. Minn., 10/22/2021
- Venue Allegations: Venue is alleged to be proper in the District of Minnesota because Defendants are incorporated in Minnesota and have regular and established places of business within the district.
- Core Dispute: Plaintiff alleges that Defendants’ QLCI Displacement Chilled Beams, a type of HVAC unit, infringe two patents related to induction-displacement air terminal units capable of simultaneous heating and cooling.
- Technical Context: The technology addresses a need in the HVAC industry, particularly for buildings in colder climates, for a single perimeter unit that can both provide heated air to offset heat loss through an exterior wall and deliver cooler displacement ventilation for air quality.
- Key Procedural History: The complaint alleges that Plaintiff provided Defendant Carson with notice of the patents-in-suit and its alleged infringement as early as May 3, 2019, and provided similar notice to Defendant Midwest Mechanical Supply on January 14, 2020, which may be relevant to the allegations of willful infringement.
Case Timeline
| Date | Event |
|---|---|
| 2011-04-20 | Priority Date for ’496 and ’899 Patents |
| 2017-01-24 | U.S. Patent No. 9,551,496 Issues |
| 2018-05-29 | U.S. Patent No. 9,982,899 Issues |
| 2019-05-03 | Plaintiff allegedly sent notice letter to Carson |
| 2020-01-14 | Plaintiff allegedly sent notice letter to MMS |
| 2021-10-22 | First Amended Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,551,496, "Displacement-Induction Neutral Wall Air Terminal Unit," Issued January 24, 2017
The Invention Explained
- Problem Addressed: The patent describes a problem with conventional induction-displacement HVAC units, which are typically placed along a building's perimeter. While effective for cooling, these units cannot provide heating without compromising their primary function; if they heat the supply air, it rises immediately instead of pooling across the floor as required for displacement ventilation. This forces the use of a separate heating system, which is often impractical due to space constraints along the same perimeter wall (’496 Patent, col. 1:46-63).
- The Patented Solution: The invention is an air terminal unit that solves this by incorporating physically separate airflow paths within a single housing. One path handles displacement ventilation by inducing room air to mix with cooled primary air, while a second, "permanently separated" path handles heating. This architecture allows the unit to simultaneously deliver a cool displacement airflow into the room and a heated airflow, typically directed up an exterior wall, from a single integrated device (’496 Patent, col. 2:1-16, Fig. 2).
- Technical Importance: This design provides a single-unit solution for year-round climate control in spaces with significant perimeter heating loads, such as classrooms, thereby improving efficiency and overcoming the spatial and functional limitations of prior systems (’496 Patent, col. 1:60-63).
Key Claims at a Glance
- The complaint asserts independent claim 9 (Compl. ¶49).
- The essential elements of independent claim 9 include:
- A housing with defined airflow paths: a supply path, a return path, and a heating path that is "permanently separated" from the other two.
- "Induction-type nozzles" in the supply path to induce airflow from the return path.
- "Displacement-type nozzles" located between the induction nozzles and the supply air outlet.
- A "heating element" and a separate "return air coil."
- An "air movement device" located in the heating airflow path.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 9,982,899, "Displacement-Induction Neutral Wall Air Terminal Unit," Issued May 29, 2018
The Invention Explained
- Problem Addressed: The ’899 patent addresses the same technical challenge as its parent ’496 patent: the inability of prior art displacement ventilation units to provide perimeter heating without defeating their ventilation function (’899 Patent, col. 1:48-65).
- The Patented Solution: The invention is an air terminal unit comprising two distinct subsystems: a "heating arrangement" (with a heating coil and outlet) and a "cooling and ventilation arrangement" (with inlets, nozzles, a cooling coil, and a displacement outlet). The patent claims a unit that is specifically "operable to simultaneously deliver" heated air from the first arrangement and cooled air from the second, achieving the dual functions in one device (’899 Patent, Abstract; col. 2:30-34).
- Technical Importance: As a continuation of the ’496 patent, this invention provides a further-defined apparatus for achieving simultaneous, separated heating and displacement ventilation from a single unit installed at a room's perimeter (’899 Patent, col. 2:1-8).
Key Claims at a Glance
- The complaint asserts independent claims 1 and 10 (Compl. ¶55). Direct infringement allegations focus on claim 10, while indirect infringement allegations focus on claim 1.
- The essential elements of independent claim 10 include:
- A housing with defined faces for mounting against a wall and floor.
- A "heating arrangement" with a heating air outlet and an upstream heating coil.
- A "cooling and ventilation arrangement" with a return air inlet, a ventilation air inlet, a displacement air outlet, induction nozzles, and a cooling coil separate from the heating coil.
- The unit must be "operable to simultaneously deliver" air heated by the heating coil and air cooled by the cooling coil.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
- Product Identification: The accused instrumentality is Defendants' "QLCI Displacement Chilled Beams" unit, particularly when configured with its "optional rear heat mode" (collectively, the "QLCI Product") (Compl. ¶17).
- Functionality and Market Context: The complaint alleges the QLCI Product is an HVAC unit that can simultaneously provide a heating airflow to an exterior wall and a separate displacement airflow to the occupied space (Compl. ¶17). This functionality is detailed in the complaint through annotated figures from the product's own literature. For example, a schematic from Defendant's literature shows separate paths for a heated "rear heat mode" and a cooled "supply air to room" mode. (Compl. ¶24, p. 7, "Figure 2 with Annotations"). The QLCI Product is alleged to be a direct competitor to the Plaintiff's products that embody the patented technology (Compl. ¶18).
IV. Analysis of Infringement Allegations
’899 Patent Infringement Allegations
| Claim Element (from Independent Claim 10) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| (a) a top face, a front face, and a back side configured to allow the housing to be mounted against the wall, and a bottom side configured to allow the housing to be mounted against the floor | The QLCI Product is a unit with a top face (D), front face (F), back side (K), and bottom side (L). An annotated photo shows an installed unit. (p. 7, "Photo 1 with Annotations") | ¶23 | col. 11:41-48 |
| (b) a heating arrangement including: (i) a heating air outlet located in one of the front face and the top face of the unit; (ii) a heating coil located upstream of the heating air outlet | The unit has a heating air outlet (C) on its top face (D) and a heating coil (B) located upstream of that outlet. (p. 7, "Figure 2 with Annotations") | ¶24 | col. 11:20-25 |
| (c) a cooling and ventilation arrangement including: (i) a return air inlet...for receiving air from the space; (ii) a ventilation air inlet for receiving pressurized ventilation air...; (iii) a displacement air outlet... | The unit has a return air inlet (E), ventilation air inlet (J), and displacement air outlet (H), all located on the front face. (p. 8, "Figure 3 with Annotations") | ¶25 | col. 12:4-10 |
| (iv) a plurality of induction-type nozzles in fluid communication with the ventilation air inlet, the induction-type nozzles inducing air flow from the return air inlet to the displacement air outlet | The unit contains induction-type nozzles (M) that receive air from the ventilation inlet and induce room air to flow from the return inlet. (p. 8, "Figure 2 with Annotations") | ¶25 | col. 6:33-40 |
| (v) a cooling coil located between the return air inlet and the displacement air outlet, the cooling coil being separate from the heating coil | The unit contains a cooling coil (G) located in the path between the return air inlet and displacement outlet, which is physically separate from the heating coil. (p. 8, "Figure 3 with Annotations") | ¶25 | col. 6:58-63 |
| (d) wherein the...unit is operable to simultaneously deliver air heated by the heating coil out of the heating air outlet and to deliver air cooled by the cooling coil out of the displacement air outlet | Product literature for the "optional rear heat mode" allegedly shows the unit is operable to deliver heated air and cooled displacement air at the same time. | ¶26 | col. 2:30-34 |
’496 Patent Infringement Allegations
| Claim Element (from Independent Claim 9) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| (a) a housing defining: ... iv. a heating airflow path defined within the housing and permanently separated from the supply and return airflow paths by at least one internal housing wall... | The QLCI Product housing contains a heating path that is alleged to be "permanently separated" from the supply and return paths by an internal wall. | ¶30 | col. 10:35-42 |
| (b) a plurality of induction-type nozzles located upstream of the supply air outlet... | The unit has induction-type nozzles (M) located within the supply airflow path. (p. 12, "Figure 3 with Annotations") | ¶31 | col. 11:10-13 |
| (c) a plurality of displacement-type nozzles located between the supply air outlet and the plurality of induction-type nozzles... | The complaint alleges that "perforated plate openings" in the unit constitute the claimed displacement-type nozzles. | ¶31 | col. 11:14-18 |
| (d) a heating element disposed within a portion of the housing defining the heating airflow path | The unit includes a heating element (B) within its heating path. | ¶32 | col. 11:19-21 |
| (e) an air movement device located within the heating airflow path configured to move air across the heating element... | The complaint alleges the heating element (B) itself also functions as the air movement device, presumably through natural convection. | ¶32 | col. 11:22-25 |
| (f) a return air coil disposed within a portion of the housing defining the return airflow stream, the return air coil being separate from the heating element | The unit includes a return air coil (G) in the return air path, which is separate from the heating element (B). | ¶33 | col. 11:26-29 |
- Identified Points of Contention:
- Scope Questions: A primary dispute regarding the ’496 patent may concern the term "air movement device." The complaint alleges the heating element itself satisfies this limitation (Compl. ¶32), while the patent discloses a "fan assembly" as a specific embodiment to "increase the rate of airflow" beyond natural convection (’496 Patent, col. 4:45-54). This raises the question of whether the passive effect of convection meets the definition of an "air movement device" as contemplated by the patent.
- Technical Questions: For the ’496 patent, the complaint provides limited visual evidence to distinguish the "induction-type nozzles" from the "displacement-type nozzles," referring only to "perforated plate openings" for the latter (Compl. ¶31). The factual basis for this distinction and whether the accused product contains both types of nozzles as distinct structures may be a point of contention.
V. Key Claim Terms for Construction
- The Term: "air movement device" (’496 Patent, Claim 9)
- Context and Importance: The infringement reading for element 9(e) of the ’496 patent hinges on this term's definition. The complaint alleges the heating coil itself serves as this device. Practitioners may focus on this term because its construction could determine whether a product without an active fan can infringe.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification notes that the "heating airflow stream 131 may occur via natural convention" (’496 Patent, col. 4:46-48). This language may support an argument that the inventors considered natural convection to be a mode of "moving air" within the path, and thus the element causing it could be considered the "device."
- Evidence for a Narrower Interpretation: The patent explicitly discloses a "fan assembly 138" (’496 Patent, Figs. 5-6) and describes its use to "increase the rate of airflow," distinguishing its function from natural convection (’496 Patent, col. 4:48-54). This may support an argument that an "air movement device" must be an active, mechanical component like a fan, rather than a passive heating element.
VI. Other Allegations
- Indirect Infringement: The complaint alleges Defendants indirectly infringe at least independent claim 1 of the ’899 patent by inducement and contributory infringement (Compl. ¶35, ¶55, ¶57). The inducement allegation is based on Defendants' marketing materials, instructions, and customer support, which allegedly encourage and instruct customers to install and use the QLCI Product in an infringing system (Compl. ¶62-63). The complaint presents a photograph of an installed unit connected to ductwork as evidence of the intended use (Compl. ¶41, p. 17, "Photo 7").
- Willful Infringement: Willfulness is alleged for both patents. The allegations are based on pre-suit knowledge stemming from notice letters allegedly sent to Defendant Carson on May 3, 2019, and to Defendant MMS on January 14, 2020 (Compl. ¶43-44). The complaint alleges that Defendants' continued manufacturing and sales after receiving these notices, and after the filing of the original complaint, were purposeful and constitute deliberate disregard for Plaintiff's patent rights (Compl. ¶45-46).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of definitional scope: Can the claim term "air movement device" in the ’496 patent, which is embodied in the specification as an active fan assembly, be construed to cover the passive effect of natural convection caused by a heating element as alleged in the complaint? The resolution of this claim construction dispute may be dispositive for infringement of that patent.
- A second central issue will be one of architectural correspondence: Does the accused QLCI Product, in its actual construction and operation, possess the distinct, "permanently separated" heating and ventilation airflow paths required by the ’496 patent and the separate functional "arrangements" claimed by the ’899 patent?
- Finally, a key question for damages will be one of willfulness: Given the complaint’s specific allegations of pre-suit notice dating back to 2019, the court will have to determine whether Defendants’ continued accused activities, if found to be infringing, rose to the level of objective recklessness required to support enhanced damages.