Cremators

A cremator comprising a primary combustion chamber for receiving through a charge door thereof a coffin or other object to be cremated and being provided with a first burner, means defining a secondary combustion chamber in communication with the primary combustion chamber and being provided with a second burner, and a retention chamber in communication with the secondary combustion chamber for temporarily retaining waste gases exhausted from the secondary and primary combustion chambers before passing to a waste flue, characterized in that at least a portion of the means defining the secondary combustion chamber comprises a tube having one end in communication with the primary combustion chamber and the opposite end opening into the retention chamber, with at least a major proportion of the tube being located within the retention chamber, and with the tube being composed of a material having a high thermal conductivity, whereby gases retained in the retention chamber are heated at least partly by direct heating from contact with the tube in the retention chamber.