1917439

Information

• Patent Grant
• 1917439

• References
• Source

• Patent Number

  1,917,439

• Date Filed

  Not available

• Date Issued

  Tuesday, July 11, 1933
  91 years ago

• CPC

  • E21F1/08 - Ventilation arrangements in connection with air ducts

• US Classifications

  • 454 - Ventilation