Abstract: A cylindrical combustion chamber for use with a hot fog generating machine is provided with a cast iron liner formed in three pieces. Each of the three pieces are spaced from the outer cylindrical shell of the combustion chamber and are provided with longitudinally directed fins which are equally spaced about the circumference of each piece. The fins in each piece are circumferentially offset from the fins on the adjacent piece so as to define a spiral passage for the gasses between the liner and the shell. An inlet is provided through the shell adjacent one end and a fuel injection nozzle and ignition device are provided adjacent the opposite end. The combustion gasses then move downwardly through the liner to an outlet at the opposite end. Upon generation of a backpressure the combustion gasses can pass outwardly of the liner to recirculate with the incoming air.

Abstract: A mobile firefighter training trailer is divided into a plurality of rooms and passages. A plurality of simulated appliances and furniture pieces are located in the various rooms of the trailer. A smoke generator is located in a separate equipment room in the trailer and is capable of selectively supplying smoke to desired locations in the trailer. Flame generating devices are associated with the simulated appliances and furniture pieces with the flames created thereby being capable of being extinguished by the proper application of water or other extinguishing agents. A ventilation system and sprinkler system are provided for the safety of the trainee.