Vanocur Refractories v. Fosbel — Coke Oven Corbel Patent Terms Get Their Plain Meaning, and “Third Passageway” Is Not Indefinite

Background

Vanocur Refractories, LLC sued Fosbel, Inc. over U.S. Patent No. 8,266,853, which covers a “corbel” for a coke oven. Coke ovens heat coal into coke, a material used to make iron and steel. A corbel sits between the oven and a heat-recycling structure called the regenerator and uses a network of passageways to move gas, fresh air and exhaust to the right places without letting them mix and ignite early. Corbels were traditionally built from hundreds or thousands of small silica bricks, which was slow and created many joints where gas or air could leak. The ‘853 Patent proposes casting larger monolithic blocks instead, reducing construction time and the number of joints.

The parties briefed the meaning of several terms in the patent’s claims and agreed to skip a claim construction hearing. The court treated claim 1 as representative. That claim recites a corbel with a first tier of blocks forming a horizontal passageway, a second tier of blocks “above” the first that forms a second passageway, a third passageway “extending diagonally from the top of the one of the second blocks to a side of at least one of the first and second blocks,” and “a gas source for providing gas to the first passageway.” A later-added defendant, Ceramic Holdings Inc., did not submit its own claim construction arguments, so the court relied on the briefs of Vanocur and Fosbel.

The Court’s Holding

“Above.” Vanocur argued the term carries a specialized meaning in this patent that requires the upper tier of blocks to sit directly on the tier below. The court disagreed and held that “above” takes its plain and ordinary meaning, which does not require adjacency. It reasoned that dependent claim 7 describes both the first and second tiers as being “above” a foundation block, which is impossible if “above” meant “directly above,” because the second tier cannot touch the foundation. Vanocur’s reliance on the specification’s drawings, which all show adjacent tiers, amounted to pointing at a preferred embodiment, and the court would not import that limitation into the claim. A single use of the phrase “directly above” in the specification was not an express definition, and the patent did not use “above” consistently enough to create an implied one. The court also declined Fosbel’s proposed wording (“in a higher, but not necessarily directly adjacent, place”) because it only restated an easily understood word in more words.

“Gas source.” The court again declined to adopt Fosbel’s proposed construction (“point of origin from which gas is obtained”) and held that no construction is needed. But because the parties disputed what structures the term covers, it clarified two points. A gas source need not be any particular type of device. It must, however, be a different structure from the “first blocks” that make up the first passageway, because those blocks are a conduit for gas rather than a source of it, the claim says the gas source provides gas to that passageway, and the two elements appear in separate claim limitations.

“Third passageway.” Fosbel argued that this limitation was indefinite, meaning it failed to tell a skilled person the scope of the invention with reasonable certainty. The court rejected each of Fosbel’s four arguments. Reading the claim against the specification and drawings, “to a side of” a block means the passageway extends into the space beside a block, not through the block’s side, particularly because other parts of claim 1 use the word “through” when they mean that. The fact that the claim does not say how close to the side the passageway must be does not make it indefinite, since descriptive terms may be broad without being subjective. “Top” of a block is easily understood, and the claim does not need to trace the full path of the passageway between its start and end. Broadness, the court said, is not indefiniteness. The court also overruled Vanocur’s objection to Fosbel’s expert, finding the expert qualified based on his years of experience with coke ovens.

The court’s table of constructions lists “above,” “gas source” and the “third passageway” limitation each as requiring no construction and carrying plain and ordinary meaning, with the third-passageway term expressly found not indefinite. The case now proceeds under the district’s Local Patent Rules.

Key Takeaways

• Courts begin with the ordinary meaning of claim words, and a patentee who wants a narrower meaning must clearly act as its own lexicographer. Consistent use of a word in drawings and examples is not enough on its own.
• A dependent claim can show that a term has a broader meaning than the independent claim’s preferred embodiment suggests.
• Declining to construct a term does not prevent the court from clarifying what it covers; here the court added that the gas source must be separate from the first blocks.
• An indefiniteness challenge based on breadth or the lack of precise measurements is unlikely to succeed when the claim and specification supply objective parameters.

Why It Matters

Claim construction rulings often decide how much of a patent survives and what products can be accused of infringing. By giving “above” its everyday meaning, the court read the claim to cover corbels whose tiers are not stacked directly on one another, rejecting the narrower reading Vanocur proposed. The court’s clarification that the gas source cannot be one of the blocks forming the first passageway narrows an argument Vanocur was making and may matter when the parties address infringement.

For patent owners and accused infringers alike, the opinion is a reminder that a district court will usually resist rewriting plain words, and that indefiniteness is a high bar for terms that are merely broad. It is a trial-court ruling made before infringement and validity are decided, so the construction may still be revisited as the case develops.