4. Refrigeration
  5. Automatic control
  6. Refrigeration producer

David N. Campbell

Inventor

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Card pay telephone with speed dialing

Telephonic communications – With check operated control – Other than coin
Reexamination Certificate

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Cryogenic cooling apparatus

Refrigeration – Refrigeration producer – Evaporator – e.g. – heat exchanger
Patent

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Cryogenic cooling apparatus

Refrigeration – Refrigeration producer – Evaporator – e.g. – heat exchanger
Patent

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Cryogenic cooling apparatus

Refrigeration – Automatic control – Refrigeration producer
Patent

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Portable phone bank

Telecommunications – Radiotelephone system – Including private cordless extension system
Reexamination Certificate

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Profile ID: LFUS-PAI-P-508700

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