DCT
1:19-cv-04523
Ecolab Inc v. Pureline Treatment Systems LLC
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Ecolab Inc. and Ecolab USA Inc. (Delaware corporations with principal place of business in Minnesota)
- Defendant: PureLine Treatment Systems, LLC (Delaware corporation) and PureLine Solutions, LLC (Illinois corporation)
- Plaintiff’s Counsel: Merchant & Gould P.C.; Goldberg Kohn Ltd.
- Case Identification: 1:19-cv-04523, N.D. Ill., 07/03/2019
- Venue Allegations: Venue is alleged based on Defendants residing in the Northern District of Illinois, maintaining a regular and established place of business in the district, and having committed alleged acts of infringement there.
- Core Dispute: Plaintiff alleges that Defendant’s chlorine dioxide generators and its "PureMax" precursor chemical product infringe two patents related to methods for producing chlorine dioxide.
- Technical Context: The technology concerns the on-site chemical generation of chlorine dioxide, a substance commonly used in industrial processes such as water purification.
- Key Procedural History: Plaintiff alleges that the parties had "prior supply agreements," which form the basis for allegations of pre-suit knowledge. U.S. Patent No. 5,895,638 was the subject of a reexamination, with a certificate issued in 2003 that amended the asserted claim. That patent expired in 2017, limiting any potential infringement remedies to past damages.
Case Timeline
| Date | Event |
|---|---|
| 1997-03-20 | U.S. Patent No. 5,895,638 Priority Date |
| 1999-04-20 | U.S. Patent No. 5,895,638 Issued |
| 2001-06-25 | U.S. Patent No. 6,790,427 Priority Date |
| 2003-01-07 | U.S. Patent No. 5,895,638 Reexamination Certificate Issued |
| 2004-09-14 | U.S. Patent No. 6,790,427 Issued |
| 2017-03-20 | U.S. Patent No. 5,895,638 Expired |
| 2019-07-03 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 5,895,638 - Method of Producing Chlorine Dioxide
Issued April 20, 1999
The Invention Explained
- Problem Addressed: The patent describes a need for improved efficiency in small-scale, on-site production of chlorine dioxide for applications like water purification (Compl. Ex. A, ’638 Patent, col. 1:8-15, 30-35).
- The Patented Solution: The invention is a process that uses hydrogen peroxide to reduce chlorate ions within a tubular reactor, in the presence of sulfuric acid. By controlling specific process parameters—such as reactant concentrations, molar ratios, and temperature—the method claims to achieve a high degree of chlorate conversion (above 75%) in a stable manner without requiring external heating or cooling, making it suitable for small-scale generation (’638 Patent, Abstract; col. 2:35-41).
- Technical Importance: The described process facilitates efficient and stable on-site generation of chlorine dioxide, which is advantageous because the chemical itself is not stable for storage and transport (’638 Patent, col. 1:13-15).
Key Claims at a Glance
- The complaint asserts independent claim 15, which was amended during reexamination (Compl. ¶8).
- Essential elements of Claim 15 (as amended) include:
- A process of producing chlorine dioxide by reducing chlorate ions with hydrogen peroxide in the presence of sulfuric acid in a tubular reactor.
- Feeding hydrogen peroxide, an alkali metal chlorate, and sulfuric acid into the reactor, where the molar ratio of H2O2:ClO3- is about 0.5:1 to 2:1, the chlorate contains less than 0.5 wt% alkali metal chloride, and the sulfuric acid concentration is 70-96 wt%.
- Reducing the chlorate ions in the reactor to form chlorine dioxide.
- Recovering the chlorine dioxide product, where about 2 to 10 kg of H2SO4 is fed per kg of ClO2 produced.
U.S. Patent No. 6,790,427 - Process for Producing Chlorine Dioxide
Issued September 14, 2004
The Invention Explained
- Problem Addressed: The patent notes the difficulty in prior art small-scale systems of producing aqueous solutions of chlorine dioxide with a sufficiently high concentration for certain applications (Compl. Ex. B, ’427 Patent, col. 1:33-39).
- The Patented Solution: The invention introduces a process where the product stream from a chlorine dioxide reactor is transferred to an eductor. Within the eductor, the product is mixed with "motive water" that is specifically made to flow in "an at least partially spiral or helical manner." This controlled flow pattern is claimed to create a more effective suction and mixing action, enabling the production of a higher-concentration final product (’427 Patent, Abstract; col. 4:9-25).
- Technical Importance: This method enhances the efficiency of diluting the gaseous chlorine dioxide product into a final aqueous solution, allowing for the on-site creation of higher-concentration solutions than previously achievable with similar direct-dilution systems (’427 Patent, col. 4:22-34).
Key Claims at a Glance
- The complaint asserts independent claim 1 (Compl. ¶21).
- Essential elements of Claim 1 include:
- A process for continuously producing chlorine dioxide.
- Feeding chlorate ions, acid, and hydrogen peroxide to a reactor.
- Reducing the chlorate ions to form a chlorine dioxide product stream.
- Feeding motive water into an eductor that has a nozzle.
- Bringing the motive water to flow through the nozzle and causing it to flow further in an "at least partially spiral or helical manner."
- Transferring the product stream from the reactor to the eductor and mixing it with the motive water.
- Withdrawing the resulting diluted aqueous solution from the eductor.
III. The Accused Instrumentality
Product Identification
- The accused instrumentalities are Defendants' "chlorine dioxide generators" and the precursor chemical product "PureMax" (Compl. ¶3). The complaint specifically references the "CG-Series-Generator" (Compl. p. 4).
Functionality and Market Context
- The accused generators are used with the PureMax chemical (alleged to contain sodium chlorate and hydrogen peroxide) and sulfuric acid to generate chlorine dioxide for industrial water and process treatment (Compl. ¶3). The complaint alleges that this process occurs in a "reactor column" and that the resulting product stream is mixed with water in an "eductor" (Compl. pp. 4, 7). The complaint positions the parties as direct competitors in the market for chemical additives for industrial processes (Compl. ¶3).
IV. Analysis of Infringement Allegations
The complaint provides a schematic diagram of the accused chlorine dioxide generator, illustrating the flow of reactants (sulfuric acid, PureMax) into a reactor column and the subsequent mixing of the product stream with motive water in an eductor (Compl. p. 4).
’638 Patent Infringement Allegations
| Claim Element (from Independent Claim 15) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A process of producing chlorine dioxide by the reduction of chlorate ions with hydrogen peroxide as a reducing agent in the presence of sulfuric acid in a tubular reactor... | PureMax is and was used to produce chlorine dioxide by the reduction of chlorate ions with hydrogen peroxide as a reducing agent in the presence of sulfuric acid in a tubular reactor. | p. 3 | US 5,895,638 C1, col. 2:15-18 |
| (a) feeding hydrogen peroxide, an alkali metal chlorate and sulfuric acid at one end of a tubular reactor... wherein the molar ratio H2O2:ClO3- is from about 0.5:1 to about 2:1, and wherein the alkali metal chlorate has less than about 0.5 wt % of alkali metal chloride and wherein the sulfuric acid feed has a concentration from about 70 to about 96 wt %; | PureLine fed... sulfuric acid and PureMax, which includes an alkali metal chlorate (sodium chlorate) and hydrogen peroxide, into one end of a tubular reactor (reactor column)... The molar ratio... was... between about 0.5:1 and about 2:1... had... less than about 0.5 wt%... The sulfuric acid feed had... a concentration from about 70 to about 96 wt %, specifically about 78%. | pp. 3-4 | US 5,895,638 C1, col. 2:19-28 |
| (b) reducing chlorate ions in the reaction mixture in said tubular reactor to form chlorine dioxide; and | PureLine, and its customers, reduced the chlorate ions in the reaction mixture in the reactor to form chlorine dioxide. | p. 4 | US 5,895,638 C1, col. 2:29-30 |
| (c) recovering a product containing chlorine dioxide at the other end of said tubular reactor, wherein from about 2 to about 10 kg H2SO4 is fed per kg ClO2 produced. | PureLine, and its customers, recovered chlorine dioxide from the reactor... About 2 to about 10 kg H2SO4... is fed per kg ClO2... produced, specifically about 4 kg. | p. 4 | US 5,895,638 C1, col. 2:31-33 |
’427 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| feeding chlorate ions, acid and hydrogen peroxide as aqueous solutions to a reactor; | PureLine, and its customers, feed acid (sulfuric acid) and PureMax (which includes chlorate ions and hydrogen peroxide), into a reactor. | p. 7 | col. 2:5-7 |
| reducing chlorate ions in the reactor to chlorine dioxide, thereby forming a product stream in the reactor containing chlorine dioxide; | The chlorate ions are reduced in the reactor to form chlorine dioxide, which forms a product stream. | p. 7 | col. 3:11-14 |
| feeding motive water in an eductor comprising a nozzle; | Water is added through an eductor nozzle. | p. 7 | col. 4:9-10 |
| bringing the motive water to flow through the nozzle and causing it to flow further through the eductor in an at least partially spiral or helical manner; | Based on at least the concentration range, upon information and belief, the motive water flows through the eductor in a spiral or helical manner. | p. 7 | col. 4:12-18 |
| transferring the product stream from the reactor to the eductor and mixing it with the motive water...; | The chlorine dioxide stream is mixed with the motive water to form a diluted aqueous solution containing chlorine dioxide. | pp. 7-8 | col. 4:18-22 |
| withdrawing the diluted aqueous solution containing chlorine dioxide from the eductor. | The diluted aqueous chlorine dioxide is withdrawn. | p. 8 | col. 2:1-4 |
Identified Points of Contention
- Scope Questions: For the ’638 patent, a question is whether the accused "reactor column" meets the definition of a "tubular reactor" as contemplated by the patent, which emphasizes plug-flow characteristics (Compl. Ex. A, ’638 Patent, col. 1:32-33).
- Technical Questions: A central technical question for the ’427 patent concerns the "at least partially spiral or helical manner" limitation. The complaint pleads this "upon information and belief," raising the question of what evidence exists that the accused eductor contains structures (such as the "twisted vanes" described in the patent specification) to induce such a flow, or whether the flow is merely turbulent (’427 Patent, col. 5:35-39; Compl. p. 7). For the ’638 patent, a key question will be whether discovery confirms that the accused process consistently operates within the specific numerical ranges for reactant ratios and concentrations required by claim 15.
V. Key Claim Terms for Construction
For the ’427 Patent:
- The Term: "at least partially spiral or helical manner"
- Context and Importance: This term is critical to the infringement analysis for the ’427 patent, as it describes the specific mechanism by which the invention achieves its claimed improvement in production capacity. The complaint’s allegation for this element is made "upon information and belief," suggesting it will be a focal point of discovery and argument (Compl. p. 7).
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language "at least partially" suggests that a perfect or substantial spiral flow is not required. The specification also states this flow can be achieved by "any suitable means" (Compl. Ex. B, ’427 Patent, col. 4:13-14), which a plaintiff may argue encompasses a wider range of flow patterns beyond those created by the specific disclosed embodiments.
- Evidence for a Narrower Interpretation: The specification provides specific structural examples for creating this flow, such as "twisted vanes" or "internal rifling" (’427 Patent, col. 4:14-15). The preferred embodiment shown in Figure 3b and described in the example explicitly uses an "insert 27... comprising twisted vanes 28" (’427 Patent, col. 5:35-39). A defendant may argue that the term requires a specific, purpose-built structure to induce the claimed flow, rather than incidental or random turbulence.
VI. Other Allegations
- Indirect Infringement: The complaint alleges both induced and contributory infringement for both patents. Inducement is based on allegations that Defendant "instructed its customers" to use its products in an infringing manner (Compl. ¶¶9, 26). Contributory infringement is based on allegations that the "PureMax" chemical is a material part of the invention, not a staple article of commerce, and lacks substantial non-infringing uses (Compl. ¶¶10, 23).
- Willful Infringement: Willfulness is alleged for both patents, based on alleged knowledge of the patents stemming from the parties' "prior supply agreements" and alleged notice of infringement (Compl. ¶¶11, 17, 24, 30).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central evidentiary question will be one of technical operation: does the motive water in the accused eductor flow in an "at least partially spiral or helical manner" as required by Claim 1 of the ’427 patent? The resolution may depend on whether the accused device contains specific internal structures to induce such a flow, as described in the patent's embodiments, or if another mechanism can satisfy the claim.
- A key factual issue for the ’638 patent will be one of consistent practice: can the plaintiff prove that the accused process, as performed by the defendant's customers using its products and instructions, consistently operates within the specific numerical ranges for reactant concentrations and ratios recited in the amended Claim 15?
- An overarching question concerning damages and willfulness will be one of knowledge and intent: given the parties’ alleged "prior supply agreements," what evidence will establish the defendant’s state of mind regarding the patents-in-suit both before and after the complaint was filed?