Method and apparatus for extruding a plurality of ribbons

Abstract

There is disclosed an apparatus and method for simultaneously forming a flow of extruded material, especially dough, into a plurality of downwardly extending ribbons each at a substantially uniform flow rate and for controlling the tendency of such ribbons to curve as they emanate from the die. The apparatus is an extrusion device which includes a housing adapted for attachment at the exit of the extruder barrel and includes an inlet passage for directing the flow of extrudant downwardly and an outwardly flared section in fluid communication with and downstream of the inlet passage. A die plate is supported by the housing downstream of the inlet and across the flared section and includes a plurality of dies having orifices for forming the extrudant into a plurality of ribbons. A generally cone-shaped mandrel is supported within the flared section of the housing in spaced apart relationship from the die plate surface and the flared section wall defining an annular flow channel for the extrudant. The method of the present invention forms a substantially cylindrical flow of extrudant under pressure into a cone-shaped envelope and vents the flow to a low pressure area through a plurality of orifices to form the desired ribbons. The thicknesses of the wall and the base of the cone-shaped flow envelope can be adjusted to maintain a uniform flow rate and to control the flow direction of the ribbons as they are extruded. The mandrel has a base radius which overlaps the outer periphery of the orifices. The orientation of the mandrel within the flared section can be adjusted to facilitate maintaining substantially equal flow rates of extrudant through the die orifices and to permit control within predetermined limits of the tendency of the ribbons to curve away from an essentially vertical path.