Complex sentence: The locomotives were equipped with Adams' "Vortex" blast pipes, which had an outer annular orifice for steam and an inner circular opening for exhaust gases, which formed the upper portion of a bell mouth scoop.
Split into simpler sentences: The locomotives were equipped with Adams' "Vortex" blast pipes. These had an outer annular orifice for steam and an inner circular opening for exhaust gases and formed the upper portion of a bell-mouth scoop.