3842721

Information

• Patent Grant
• 3842721

• References
• Source

• Patent Number

  3,842,721

• Date Filed

  Not available

• Date Issued

  Tuesday, October 22, 1974
  50 years ago

• CPC

  • E04F17/02 - for carrying away waste gases
  • F23J13/025 - composed of concentric elements
  • F23J2213/202 - between duct or stack sections
  • F23J2213/40 - Heat insulation fittings

• US Classifications

  • 454 - Ventilation
  • 138 - Pipes and tubular conduits