Extrusion head with spiral-channel distributor element

US6551089B1 · kind B1 · utility

Inventors

• Peter Langos · Sankt Augustin, DE
• Manfred Lehmann · Cologne, DE
• Stefan Keusch · Münstermaifeld, DE

Key dates

• Filing date: Jan 17, 2001
• Grant date: Apr 22, 2003
• Expiry date: Jan 17, 2021

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B29C48/475
• WIPO field: Other special machines
• WIPO sector: Mechanical engineering

Abstract

The invention relates to an extrusion head (10) for a blow molding machine for producing two-layered hollow plastic bodies, including one or more extruders, connected to the extrusion head housing (12), for supply of molten plastic melt. In particular when using different plastic materials of different viscosities, it is very important to create for both materials substantially the same rheological flow conditions when distributed across the circumference to form a tubular parison. This is attained in accordance with the invention by making the ejector piston of two concentric cylindrical sleeves which define between them an annular gap in which the two spiral-channel distributor elements are located in opposite disposition inside on the inner surface of the outer cylindrical sleeve and outside on the outer surface of the inner cylindrical sleeve, so that the circumferentially distributed plastic materials of both distributor elements exit at the lower end of the annular gap approximately centrally from the ejector piston into the storage space of the extrusion head.