Serial two-stage extruder
US5413475A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 1, 1993 |
| Grant date | May 9, 1995 |
| Priority date | — |
| Expiry date | Mar 1, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/83
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
In a serial two-stage extruder, the first-stage extruder has a screw including a feed screw section having a length within a range of 5 to 9 the major diameter thereof, a mixing screw section having a hexagonal cross section and a pitch of 1 to 3 times the major diameter thereof, and a metering screw section having a screw groove of an appropriate depth. The second-stage extruder includes an extruding screw and a barrel. The extruding screw has a screw groove of an appropriate depth and a dulmage formed at the tip end of the screw. The dulmage has a plurality of fins cooperating with fins of the barrel. Alteratively, in the second-stage extruder, the dulmage may have a plurality of axially spaced stages of fins. Configurations of the fins in each respective stage are identical but various characteristics of the fins vary from stage to stage. In this case, the barrel does not have fins.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.