Invalidity dossier
US 5293930
Surface-to-air heat exchanger for electronic devices
Current assignee: HP Inc
Added 9/23/2026, 4:23:28 PM
Active provider: DeepSeek · deepseek-flash
Patent summary
Title, assignee, inventors, filing/issue dates, abstract, and a plain-language overview of the claims.
Patent Overview — US 5,293,930 A
Title: Surface-to-air heat exchanger for electronic devices
Inventor: Martin J. Pitasi
Original Assignee: Hewlett-Packard Company (current assignee of record: HP Inc.)
Application No.: US 07/950,207 | Filed / Priority Date: 1992-09-24
Granted / Published: 1994-03-15 | Legal Status: Expired – Lifetime
Purpose. The patent addresses a limitation of conventional finned heat exchangers: they must be aligned so their fins run parallel to the cooling air flow, meaning airflow direction has to be known before mounting. The disclosed heat exchanger is intended as a versatile, omnidirectional, high-efficiency surface-to-air cooler for electronic devices.
Plain-language scope. The device has two main parts: a thermally conductive spacer mounted to a surface of an electronic device, and a thermally conductive disk-shaped fin centered on the spacer. The spacer is preferably circular and smaller in diameter than the fin. The fin provides opposed circular heat-exchanging surfaces extending radially from the spacer and lying generally parallel to the device surface. Because the surfaces are circular, effective boundary-layer growth along the airflow direction is reduced, and high-conductivity material (aluminum or copper) plus suitable geometry yield low thermal gradients — described as substantially isothermal surfaces with fin effectiveness on the order of 90–100%, versus roughly 50–70% for typical rectangular-fin designs. The compact envelope permits higher airflow velocities. Additional alternating spacer-disks and fin-disks may be stacked to meet a given heat-transfer requirement. In the illustrated embodiment the exchanger has a threaded hole so it can be screwed onto a stud of an interface plate, with spanner holes for applying torque.
What the supplied excerpt does not establish. The excerpt is partial (it ends mid-sentence) and does not include the full claims, complete figure descriptions, or the full specification text. It states only that the application was filed, assigned, and granted, and that the patent expired by anticipated expiration on 2012-09-24; it does not establish claim scope, litigation, validity, ownership beyond the listed assignments, or prior-art content. Classifications listed include H10W40/22 and H10W40/43.
Generated 10/1/2026, 9:50:55 PM
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Litigation summary
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PTAB challenges
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Assignment history
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Prior art
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Obviousness
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Extensions
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Derivative works
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