Invalidity dossier
US 176913
Improvement in tuyeres
Added 9/23/2026, 6:56:57 PM
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Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview: US176913A — "Improvement in Tuyeres"
Title: Improvement in Tuyeres
Patent number: US176913A
Inventor: Thomas F. Witherbee, of Port Henry, County of Essex, New York
Filed: February 28, 1876
Granted/Published: May 2, 1876
Anticipated expiration: May 2, 1893; status listed as Expired – Lifetime
Classification: C21B7/16 (Tuyères, under Blast furnaces)
Source: https://patents.google.com/patent/[US176913](/patent/US176913)/en
Purpose and plain-language scope
The patent concerns a water-cooled tuyere (the nozzle that injects air into a blast furnace). It addresses two practical problems: uneven water circulation in the cooling chamber, and trapped air on the water-inlet side.
The specification describes a partition (E) placed in the water-chamber between the water inlet and outlet (G), forcing water to travel entirely around the tuyere before exiting. To keep air from accumulating on the inlet side, the partition includes air-passages (H) sized to let air escape without letting much water through.
As a stated modification, the inventor proposes dispensing with the partition plate and instead using a long induction-tube (I) that enters the water-chamber at one end and extends to near the other end, itself acting as a partition to circulate water out through the eduction opening or tube (G).
The specification also notes that the tuyere (A) is tapered divergingly — flared in the opposite direction from the nozzle (B) — which is said to simplify and facilitate cleaning and largely prevent lodgment of obstructions.
Claims (3):
- The tuyere A, flared in an opposite direction from nozzle B.
- The partition E in the water-chamber between the inlet and outlet.
- The partition E having the air-passages H.
What the excerpt does not establish
The supplied text names no assignee. It provides no drawing figures, dimensional data, or materials. It does not state whether the flared and partitioned/tube embodiments were claimed together or used together. It contains no information on litigation, ownership transfers, validity, or prior art beyond two later citing patents (US3043578A and US3061300A, both United States Steel Corp.). Any legal-status statement is expressly an assumption, not a legal conclusion.
Generated 10/1/2026, 9:42:24 PM
Cases on file (0)
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Litigation summary
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Proceedings on file (0)
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No PTAB proceedings on file. This patent has not been challenged via IPR, PGR, or CBM. The absence is itself a signal — well-asserted patents eventually attract IPRs. The LLM analysis below may surface filings the ODP feed hasn’t indexed yet.
PTAB challenges
AIA trial proceedings at the USPTO Patent Trial and Appeal Board — IPR, PGR, and CBM. Petitioners, judge panels, claim-level invalidation outcomes from Final Written Decisions, and Federal Circuit appeals. The single most important defensive datapoint after litigation history.
Assignment history
Inventors, original assignee, and the chain of ownership recorded with the USPTO — including the correspondent attorney who recorded each assignment, since shell-LLC chains often share one repeat-player attorney even when the entity names look unrelated. Surfaces NPE / patent-troll patterns: shell-entity transfers, known asserters in the chain, repeat correspondent fingerprints, pre-litigation assignments, and bankruptcy fire-sales.
Prior art
Earlier patents, publications, and products that may anticipate or render the claims unpatentable.
Obviousness
Combinations of prior art that suggest the claimed invention would have been obvious under 35 U.S.C. § 103.
Extensions
Patent term adjustments, term extensions, continuations, divisionals, family members, and expiration dates.
Derivative works
Defensive disclosure: derivative variations of each claim designed to render future incremental improvements obvious or non-novel.