USD252041SExpiredUtility

Fireplace heat exchanger device

29
Assignee: ENERGY CONSERVING EQUIPMENT INCPriority: Aug 4, 1977Filed: Aug 4, 1977Granted: Jun 5, 1979
Est. expiryAug 4, 1997(expired)· nominal 20-yr term from priority
Inventors:Robert L. WilliamsFrank M. WilliamsJ. A. Gareth Williams
29
PatentIndex Score
2
Cited by
3
References
1
Claims

Claims

exact text as granted — not AI-modified
The ornamental design for a fireplace heat exchanger device, as shown.

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