Extrusion of tubes of fiber-reinforced thermoplastics
US5307843A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 1992 |
| Grant date | May 3, 1994 |
| Priority date | — |
| Expiry date | Mar 9, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/139
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Fibre-reinforced tubes made of a thermoplastics material are manufactured using a method of extruding thermoplastics material in a drawplate with a diverging end zone, the end zone of which has a diverging annular flow space which has a ratio A.sub.s /A.sub.e between the exit area and entry area of at least 1.2, and a ratio between the length 1 of the lower edge of the annular exit space of the diverging zone and the width e of the straight section of said annular space which is less than 5; the extrusion operation being carried out in the presence of a liquid lubricant which is incompatible with said thermoplastics material at extrusion temperatures, said lubricant being present at the level of the external wall and at the level of the internal wall of said flow space. Tubes which are manufactured by way of this method are particularly resistant to a high degree of bursting and have an improved surface quality.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.