Abstract: An inlet spool for controlling the back flow of molten glass from a submerged combustion melter. The inlet spool includes a pipe having a first end, a second end, and an inner wall defining a passageway between the first end and the second end. A cross-sectional area of the passageway increases along a length of the passageway from the first end to the second end toward the melter. The passageway may be conical-shaped.