| 1/00 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) |
| 1/02 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) with counter-current only |
| 1/04 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) with cross-current only |
| 1/06 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) with both counter-current and cross-current |
| 1/08 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) Arrangements for recovering heat from exhaust steam |
| 1/10 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) Arrangements for suppressing noise |
| 1/12 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) Arrangements for preventing clogging by frost |
| 1/14 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) comprising also a non-direct contact heat exchange |
| 1/16 | Direct-contact trickle coolers, e.g. cooling towers (building construction E04H 5/12; enclosed spaces cooled by trickle F25; component parts of trickle coolers F28F 25/00) Arrangements for preventing condensation, precipitation or mist formation, outside the cooler (F28C 1/14 takes precedence) |
| 3/00 | Other direct-contact heat-exchange apparatus |
| 3/02 | Other direct-contact heat-exchange apparatus the heat-exchange media both being gases or vapours |
| 3/04 | Other direct-contact heat-exchange apparatus the heat-exchange media both being liquids |
| 3/06 | Other direct-contact heat-exchange apparatus the heat-exchange media being a liquid and a gas or vapour (temperators for cooling steam F22) |
| 3/08 | Other direct-contact heat-exchange apparatus the heat-exchange media being a liquid and a gas or vapour (temperators for cooling steam F22) with change of state, e.g. absorption, evaporation, condensation (generating steam under pressure F22) |
| 3/10 | Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material |
| 3/12 | Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material the heat-exchange medium being a particulate material and a gas, vapour, or liquid |
| 3/14 | Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material the heat-exchange medium being a particulate material and a gas, vapour, or liquid the particulate material moving by gravity, e.g. down a tube |
| 3/16 | Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material the heat-exchange medium being a particulate material and a gas, vapour, or liquid the particulate material forming a bed, e.g. fluidised, on vibratory sieves |
| 3/18 | Other direct-contact heat-exchange apparatus one heat-exchange medium at least being a fluent solid, e.g. a particulate material the heat-exchange medium being a particulate material and a gas, vapour, or liquid the particulate material being contained in rotating drums |