Multi-screw extruder
US4818206A · kind A · utility
Inventor
Key dates
| Filing date | Oct 7, 1987 |
| Grant date | Apr 4, 1989 |
| Priority date | — |
| Expiry date | Oct 7, 2007 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/03
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The inside surface of an extrusion cylinder (1) is divided into an upper surface (2) and a lower surface (3), each in the shape of an arc of a cylinder. The two surfaces intersect so that two screw sections (8, 9), each provided with a helical thread (12, 13), mesh with each other. The two threads are complementary in that the width of one thread (12 ) gradually increases from an entry opening (6) downstream, while the width of the other thread (13) decreases gradually from the upstream end toward the exit opening (7). Owing to separations between the free spaces, the material poured into the extruder through the entry opening is forced to pass once into a working zone in order to reach an exit chamber where the pressure is less than in the entry chamber.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.