Extrusion device having intermediate extruder

Claim 1

An extrusion device for extruding pasty and thermoplastic materials, comprising a housing having a wall, a first rotor rotatably mounted in said housing and having a peripheral surface spaced from said wall and defining with said wall a first material infeed passage portion and an extrusion passage portion, a second material infeed passage defined in said wall communicating centrally with and between said first material infeed passage portion and said extrusion passage portion, a first adjustable extrusion device extending into said extrusion passage portion by an amount to extrude material flowing from said first material infeed passage to said extrusion passage portion to cause it to form into a layer spaced from said wall and to move over said first rotor, a second adjustable extrusion device projecting into said extrusion passage downstream of said first adjustable extrusion device, said second adjustable extrusion device and said first adjustable extrusion device being adjusted so that said extrusion passage does not remain full and is thus without pressure, said second adjustable extrusion device being set to effect a build-up of material therebehind and to form a laminate of the buildup material with the layer on said first rotor to effect a boundary layer breaking up of the extruded layers as they pass by said second adjustable extrusion device, and including bypass means associated with said second extrusion device for bypassing a portion of the material accumulated in said extrusion passage behind said second extrusion device.