Disclosed is an apparatus and a corresponding method for producing a continuous foamed extrudate product in which the extrusion and initial expansion of the foamed extrudate is conducted within a chamber under a partial vacuum. The foamed extrudate is then removed from the chamber through an orifice submerged within a liquid baffle. The dimensions of the foamed extrudate are monitored as it approaches the orifice and, if necessary, the effective sizing of the orifice is adjusted through the movement of a pair of side gates and a single vertical gate arranged external the orifice to match opening to the foamed extrudate and impede the flow of liquid into the chamber through the orifice.