3877638

Information

• Patent Grant
• 3877638

• References
• Source

• Patent Number

  3,877,638

• Date Filed

  Not available

• Date Issued

  Tuesday, April 15, 1975
  49 years ago

• CPC

  • B60H1/00442 - using a vacuum
  • B60H1/00485 - Valves for air-conditioning devices
  • G05D23/1925 - using a combination of auxiliary electric and non-electric power
  • G05D23/24 - the sensing element having a resistance varying with temperature

• US Classifications

  • 237 - Heating systems
  • 165 - Heat exchange
  • 236 - Automatic temperature and humidity regulation