CPC Main Group F03G 4/00 Devices for producing mechanical power from geothermal energy 13 direct subcodes Child Classifications Navigate with arrow keys, Enter to open F03G 4/001 F03G 4/02 with direct fluid contact F03G 4/023 F03G 4/031 F03G 4/033 F03G 4/037 F03G 4/04 with deep-well turbo pump F03G 4/045 F03G 4/06 with fluid flashing F03G 4/063 F03G 4/069 F03G 4/072 F03G 4/074