Abstract: An extruder die head for producing multilayered tubes made of thermoplastic material exhibits a central annular channel, which is provided with an annular outlet die. Into the outer limiting wall of the channel empty annular slits, which feed a polymer melt and which constitute the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked, conical insert members. To reduce the axial length of the extruder die head, the annular slits, feeding the polymer melts, also empty into the inside wall of the central annular channel. The annular slits are the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked conical internal insert members.

Abstract: An extruder die head comprises an internal cylindrical mandrel and a shell, which encloses said mandrel concentrically. Between said mandrel and shell an annular channel is formed that empties into the die slit. A polymer melt is fed through a line to the annular channel. To prevent the polymer melt in the area of the start of the annular channel from penetrating into a slit that forms between the mandrel and the shell due to heat expansion, there is between both mandrel and shell a ring with such a coefficient of thermal expansion that when heated up due to the polymer melt said ring seals the slit between the shell and the mandrel.

Abstract: An extruder die head for producing multilayered tubes made of thermoplastic material exhibits a central annular channel, which is provided with an annular outlet die. Into the outer limiting wall of the channel empty annular slits, which feed a polymer melt and which constitute the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked, conical insert members. To reduce the axial length of the extruder die head, the annular slits, feeding the polymer melts, also empty into the inside wall of the central annular channel. Said annular slits are the smaller diameter openings of truncated channels, formed between the internal and external shells of stacked conical internal insert members.

Abstract: An extruder die head, preferably a blown film head, has an internal cylindrical mandrel and a cylindrical jacket, which envelops concentrically the mandrel. Between the mandrel and jacket an annular channel is formed that empties into a die slit. At least one melt-supplying line empties into the annular channel in the area opposite the die slit. To avoid slits between the central mandrel and the jacket, enveloping the mandrel, where the polymer melt can accumulate and deposit, the mandrel is made as one piece with a flange-like foot and is provided in the area, adjacent to the foot, with at least one borehole, which feeds in the melt. On the mandrel adjacent to the foot is shrunk a ring, which seals the slit between both the mandrel and jacket. The cylindrical jacket is mounted above and connected sealingly to the shrunk-on ring to form the annular channel.

Abstract: An extruder die head, preferably a blown film head, comprises an internal cylindrical mandrel and a jacket, which envelops concentrically said mandrel. Between said mandrel and jacket an annular channel is formed that empties into a die slit. At least one melt-supplying line empties into the annular channel in the area opposite the die slit. To avoid slits between the central mandrel and the jacket, enveloping said mandrel, where the polymer melt can accumulate and deposit, the mandrel is made as one piece with a flange-like foot and is provided in its area, adjacent to the foot, with at least one borehole, which feeds in the melt. On the mandrel adjacent to the foot is shrunk a ring, which seals the slit between both. On the ring is mounted a cylindrical jacket and is connected sealingly to said jacket, which envelops the mandrel, forming an annular channel.