Abstract: A refuse incinerator has a grate surmounted by an enclosed generally vertical combustion chamber terminating with a chimney. Several internal pipes deliver streams of primary air to several levels in the lower part of the chamber for combustion of the refuse, and tangential and radial streams of heated secondary air at several levels in the upper part of the chamber for combustion of the rising gases. Additional pipes of inverted U form, extending over the entire height of the chamber and having an inlet end of greater section than the outlet end, deliver heated primary air in the proximity of the grate, which enables relatively humid refuse to be satisfactorily incinerated without auxiliary burners.