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US3520525A Expired / Lapsed US ⏱️ 0.0 years remaining

Apparatus for delivering air to a blast furnace

Assignee: Beazer East Inc
•
Filing: 1967-11-15
•
Granted: 1970-07-14
•
Expires: 1987-11-15
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Abstract

No abstract record available.

Inventors

  • 👤 Robert E Zimmermann

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 06:14
CPC Classifications
C; C21; C21B; C21B7/00; C21B7/16

Claims Analysis

Total Claims: 0
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References Cited (Backward Citations)

US1844194A Cited
US1847835A Cited
US3088725A Cited
US3255734A Cited
US3281135A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1973-07-13 1974-01-12 1974-07-14 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1977-07-13 1978-01-12 1978-07-14 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1981-07-13 1982-01-12 1982-07-14 $7700.00 Window Closed / Lapsed

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