2781557

Information

• Patent Grant
• 2781557

• References
• Source

• Patent Number

  2,781,557

• Date Filed

  Not available

• Date Issued

  Tuesday, February 19, 1957
  67 years ago

• CPC

  • E04B9/0471 - having a trapezoidal cross section
  • F24F7/10 - with air supply, or exhaust, through perforated wall, floor or ceiling
  • F24F13/068 - formed as perforated walls, ceilings or floors

• US Classifications

  • 454 - Ventilation
  • 052 - Static structures