Chambers are arranged around the engine and the air is delivered into ducts in each chamber. Each chamber has an inner flame tube. All the tubes are interconnected which allows each tube to operate at the SAME pressure. The early axial flow compressor engines used this type of chamber. The burners are arranged in a circular fashion around the engine. Each chamber has a separate flame tube although they are all interconnected. Each tube operates at the same pressure which provides identical operating conditions.