DCT
1:21-cv-00942
Glaston Corp v. HHH Equipment Resources
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Glaston Corporation and Uniglass Engineering Oy (Finland)
- Defendant: HHH Equipment Resources and Salem Fabrication Technologies Group, Inc. (North Carolina)
- Plaintiff’s Counsel: Parker Poe Adams & Bernstein LLP; Sughrue Mion, PLLC
- Case Identification: 1:21-cv-00942, M.D.N.C., 12/09/2021
- Venue Allegations: Venue is alleged to be proper as Defendants are incorporated in North Carolina and therefore "reside" within the judicial district.
- Core Dispute: Plaintiffs allege that Defendants’ distribution and sale of Northglass-brand convection glass tempering furnaces infringe two patents related to dual-sided glass heating methods and apparatuses.
- Technical Context: The technology concerns industrial furnaces for tempering glass, a process that requires precise and uniform heating to impart strength and safety characteristics without causing optical distortions.
- Key Procedural History: The complaint alleges that Plaintiffs provided Defendants with notice of the patents-in-suit and their belief of infringement in November 2020, approximately one year before filing the lawsuit.
Case Timeline
| Date | Event |
|---|---|
| 2003-06-24 | '540 and '911 Patent Priority Date |
| 2013-07-09 | U.S. Patent 8,479,540 Issued |
| 2014-02-18 | U.S. Patent 8,650,911 Issued |
| 2020-11-XX | Plaintiffs allegedly notified Defendants of infringement |
| 2021-12-09 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,650,911 - Method and Apparatus for Heating Glass, issued Feb. 18, 2014
The Invention Explained
- Problem Addressed: The patent addresses the problem of uneven heating in glass tempering furnaces where glass is transported on ceramic rollers. Heat transfer from the hot rollers can cause the bottom of a glass sheet to heat faster than the top, leading to warping and optical defects, a problem exacerbated when processing coated "selectivity glass" that strongly reflects radiant heat. ('911 Patent, col. 1:26-40).
- The Patented Solution: The invention proposes a dual-circuit convection heating system. The top surface of the glass is heated by blowing recycled, already-hot air drawn from inside the furnace. Simultaneously, the bottom surface is heated by blowing fresh air taken from outside the furnace, which is then separately pressurized and heated before being applied to the glass. ('911 Patent, col. 2:10-27, Fig. 1). This combination is designed to provide more balanced and controllable heat application to both surfaces.
- Technical Importance: This approach is described as enabling faster and more uniform heating for difficult-to-process glass types while avoiding the cost and complexity of prior art systems that used hot air for both top and bottom heating. ('911 Patent, col. 2:38-41, 2:1-4).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶22).
- The essential elements of Claim 1 include:
- A tempering furnace with horizontal rolls to form a conveyor.
- An upper circuit comprising an upper side return pipe, a pressurization unit to pressurize air sucked from inside the furnace, and means to blow that air onto the upper glass surface.
- A lower circuit comprising a compressor to pressurize air taken from outside the furnace, a pipe system to convey it to the lower glass surface, and means for heating that air.
- The complaint reserves the right to assert additional claims (Compl. ¶33).
U.S. Patent No. 8,479,540 - Method and Apparatus for Heating Glass, issued Jul. 9, 2013
The Invention Explained
- Problem Addressed: The patent addresses the same technical challenge as the '911 Patent: non-uniform heating of glass on oscillating rollers, particularly the tendency for the bottom surface to overheat from contact with the rollers. ('540 Patent, col. 1:21-34).
- The Patented Solution: The invention claims a method that embodies the dual-circuit heating concept. The method consists of heating the top surface using recycled furnace air while heating the bottom surface with fresh, externally sourced air that is pressurized and heated. ('540 Patent, col. 2:1-11). The specification notes that this allows the temperature in the bottom part of the furnace to be kept "quite low," supplying heat only when and where it is needed. ('540 Patent, col. 2:38-44).
- Technical Importance: The claimed method provides a way to achieve a high heating rate and better thermal control, which is critical for maintaining the optical quality of the finished tempered glass. ('540 Patent, col. 2:31-35).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶41).
- Claim 1 is a method claim where the "improvements consist[] essentially of":
- Heating the upper glass surface by sucking, pressurizing, and recycling hot air from inside the furnace.
- Heating the lower glass surface by blowing air that has been taken from outside the furnace, pressurized by a compressor, and heated.
- The complaint reserves the right to assert additional claims (Compl. ¶48).
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are "AU series glass tempering furnaces" manufactured by Luoyang North Glass Technology Co., Ltd. ("Northglass") and imported, offered for sale, and sold by Defendants (Compl. ¶1, ¶23).
Functionality and Market Context
The complaint alleges the accused furnaces operate using a dual-heating system described as "Upper convection heating" and "Bottom aspiration" (Compl. ¶24, ¶27). The upper convection is alleged to use "hot air delivered through top air nozzles and recirculated on the upper side to an intake of the furnace blowers" (Compl. ¶24). The "bottom aspiration" is alleged to use "compressed air to supply to the bottom surface of the glass and aid in heating" (Compl. ¶27). A screenshot from a marketing video shows an icon for the furnace labeled "TOP CONVECTION BOTTOM ASPIRATION" (Compl. p. 9). Defendants are described as the exclusive partner and authorized North American agent for Northglass equipment (Compl. ¶30-31, ¶46).
IV. Analysis of Infringement Allegations
'911 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| An apparatus for heating glass, the apparatus comprising a tempering furnace comprising horizontal rolls arranged to carry the glass and to form a conveyor thereof, | The accused Northglass AU series furnaces are apparatuses for heating glass that include a tempering furnace with horizontal rolls. A product screenshot identifies "Horizontal rollers forming conveyor." | ¶23; p. 8 | col. 5:19-21 |
| an upper side return pipe for sucking air from inside the tempering furnace, | The accused furnaces allegedly have "an upper side return pipe for drawing air from inside the tempering furnace," with air "recirculated on the upper side to an intake of the furnace blowers." | ¶24, ¶25 | col. 5:50-54 |
| a pressurization unit for pressurizing the air sucked from inside the tempering furnace, | The accused furnaces allegedly have "multiple blowers in blower housings mounted to the side of the furnace for pressurizing air." A screenshot identifies these "Blower housings." | ¶26; p. 10 | col. 5:48-49 |
| means for blowing the pressurized air back to an upper surface of the glass, | The furnaces allegedly "heat the glass from the top with gapless forced convection with hot air delivered through top air nozzles." | ¶24 | col. 5:6-10 |
| a compressor for pressurizing air taken from outside the furnace, | The furnaces are alleged to "employ bottom aspiration, using compressed air." This function is implicitly alleged to be performed by a compressor. | ¶27 | col. 6:39-40 |
| a pipe system for conveying the air pressurized by the compressor to a lower surface of the glass, and | The accused furnace allegedly "delivers the compressed air to the bottom surface of the glass via air openings in conduits located beneath the glass/rollers." | ¶45 | col. 6:21-23 |
| means for heating the air pressurized by the compressor. | The use of "bottom aspiration" is alleged to "aid in heating," implying the compressed air is heated. | ¶27 | col. 6:30-32 |
'540 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| In a method of heating glass, the method comprising conveying glass through a tempering furnace during a heating cycle so that the glass is heated from above and below... | The accused furnaces are apparatuses for heating glass from above and below and convey glass on horizontal rolls. | ¶42 | col. 6:51-53 |
| heating an upper surface of the glass by hot air jets formed by sucking hot air from inside the furnace, pressurizing the hot air and recycling the pressurized hot air back to the upper surface... | The accused furnaces are alleged to perform "Top Convection" by heating the upper surface with "pressurized hot air recycled from the surface of the glass back through an intake of the furnace blowers." | ¶43 | col. 6:55-58 |
| blowing air which has been taken from outside the furnace and which has been pressurized by a compressor and heated onto a lower surface of the glass for the heating from below. | The accused furnaces allegedly employ "bottom aspiration," which is described as using "compressed air" delivered to the bottom surface to aid in heating. A screenshot annotates the furnace features as "Top Convection Bottom Aspiration." | ¶44, ¶45; p. 17 | col. 6:60-63 |
Identified Points of Contention
- Technical Questions: A primary factual question is whether the accused "bottom aspiration" system functions as claimed. What evidence supports the allegation that this system uses a "compressor" that draws air from outside the furnace, as opposed to an alternative mechanism? The complaint uses the term "compressed air" but provides limited detail on the specific components and air source for the bottom-heating circuit (Compl. ¶27, ¶44).
- Scope Questions: For the '540 Patent, the transitional phrase "consisting essentially of" raises the question of whether any other heating mechanisms in the accused process—such as conductive heat from the ceramic rollers, the very problem the patent sought to solve—materially affect the basic and novel properties of the claimed method.
V. Key Claim Terms for Construction
The Term: "compressor" ('911 Claim 1; '540 Claim 1)
- Context and Importance: This term is central to the infringement analysis for the bottom-heating circuit. The dispute may turn on whether the component in the accused "bottom aspiration" system that pressurizes air qualifies as a "compressor" that takes air from outside the furnace, as required by the claims.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party may argue for the term’s plain and ordinary meaning, which could encompass a wide range of devices that increase the pressure of a gas. The patent does not appear to provide a special definition.
- Evidence for a Narrower Interpretation: The patent specification and Figure 1 depict the "compressor" (17) as a distinct component from the "pressurization unit" (10) used for the upper circuit. ('911 Patent, Fig. 1). A party could argue the term requires a structurally separate component that draws air from the "factory hall," distinct from the furnace's internal air circulation system. ('911 Patent, col. 6:35-36).
The Term: "consisting essentially of" ('540 Claim 1)
- Context and Importance: Practitioners may focus on this term because it limits the claim to the recited steps and any unrecited steps that do not materially alter the "basic and novel characteristics" of the invention. This creates a potential non-infringement defense if the accused process includes additional, material heating steps.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation (i.e., less limiting): A party could argue that minor, inherent heat transfer (e.g., from rollers) does not materially alter the invention, whose core is the active dual-convection heating method.
- Evidence for a Narrower Interpretation (i.e., more limiting): The "basic and novel characteristic" is arguably the specific combination of two different convection heating modes to solve the problem of uneven heating caused by the rolls. ('540 Patent, col. 1:21-34). A party could argue that any substantial, unrecited source of heat, particularly on the bottom side, would materially alter this characteristic and thus place the accused method outside the claim's scope.
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement based on Defendants' "active marketing and promotion," as well as providing "installation, training and customer support" that allegedly encourage customers to operate the furnaces in an infringing manner (Compl. ¶34, ¶49).
- Willful Infringement: The willfulness claim is based on alleged pre-suit knowledge. The complaint states that Plaintiffs notified Defendant HHH of the patents and the alleged infringement in November 2020, but that Defendants continued their accused activities (Compl. ¶36, ¶51).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of evidentiary proof: Can Plaintiffs demonstrate that the accused "bottom aspiration" feature of the Northglass AU series furnace operates as claimed? Discovery into the furnace's actual design and function will be critical to determine if it truly uses a "compressor" that draws and heats air from outside the furnace, or if it employs a technically distinct method.
- The case may also turn on a question of claim scope: For the method claims of the '540 Patent, what is the scope of "consisting essentially of"? The court may need to define the invention's "basic and novel characteristics" to determine whether any heat transfer inherent in the accused process, such as from the conveyor rollers, is significant enough to materially alter those characteristics and thereby avoid infringement.