3861462

Information

• Patent Grant
• 3861462

• References
• Source

• Patent Number

  3,861,462

• Date Filed

  Not available

• Date Issued

  Tuesday, January 21, 1975
  50 years ago

• CPC

  • B21C37/0803 - the tubes having a special shape
  • B21C37/083 - Supply, or operations combined with supply, of strip material
  • F28F1/42 - the means being both outside and inside the tubular element
  • F28F1/426 - the outside portions and the inside portions forming parts of complementary shape
  • Y10S29/023 - Method or apparatus with knurling
  • Y10S165/515 - Patterned surface

• US Classifications

  • 165 - Heat exchange
  • 029 - Metal working