Plastic extrusion apparatus and method
US4336213A · kind A · utility
Inventor
Key dates
| Filing date | Feb 6, 1980 |
| Grant date | Jun 22, 1982 |
| Priority date | — |
| Expiry date | Feb 6, 2000 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF04C13/001
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A plastic extrusion apparatus is provided which includes a gear pump for accurately metering the plastic through a die. The apparatus is adapted to process highly viscous plastic material under high temperature and pressure conditions, and the gear pump includes a non-leaking and substantially frictionless seal for the drive shaft. The seal comprises a sleeve surrounding the shaft, and a shallow helical channel formed in the bore of the sleeve, with the helical channel being of a hand such that forward rotation of the shaft results in the plastic which enters the clearance between the shaft and sleeve to be effectively pumped back toward the interior of the housing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.