Patent ID: 8708688

Claim:
A thermally insulated extrusion die plate assembly for a pelletizer including a plurality of extrusion orifices through which process melt is extruded to exit at a cutting face as a strand to be cut into pellets by a moving cutting assembly which comprises: (a) a die plate body having a central portion, said central portion of said die plate body being cut out on a downstream face of said die plate body to form a recess or a cavity that is centrally positioned in said downstream face; (b) at least one ring of extrusion orifice extensions extending through said cavity; (c) a cover plate sized to fit over said cavity and having openings which mate with said extrusion orifices therethrough to form said cutting face, said over plate attached to said die plate body over said cavity; said cover plate and said cavity forming and defining a thermally insulating centrally positioned air chamber in said assembly adjacent said cutting face, said orifice extensions through-penetrating said air chamber to surround and insulate said orifice extensions to provide continuous heating along a length of the through-penetrating orifice extensions and to prevent heat loss from the process melt adjacent the cutting face; and (d) an air vent open to a surrounding atmosphere outside the die plate assembly so that pressure build up is prevented and air in said air chamber is maintained at a same atmospheric pressure as air in said surrounding atmosphere outside of said die plate assembly.