Subclass Subgroup Patent
F24C 3/124 12169071
  15/006 12169070
F24D 19/1009 12169072
F24F 1/0011 12169073
  5/0092 12169077
  11/36 12169074
  11/84 12169075
    12169076
F24H 1/102 12169078
  9/2028 12169079
F24S 23/31 12169080