Abstract: A vent adapted for use with a devolatilizer having a mechanical press includes a closed vent chamber extending generally vertically above the mechanical press and having a horizontal cross-sectional area which increases from the bottom to the top of the vent chamber. An input opening at the bottom of the chamber communicates with the mechanical press and an extraction port adjacent the upper portion of the chamber removes the vapors from the chamber and transports them to volatile recovery apparatus or disposal apparatus. A tamping means, including one or more actuatable tamping rods in the vent chamber, is provided for forcing the material being processed back into the mechanical press. The vent is maintained free of particle build-up and the processed material is returned to the mechanical press.