Blowing agent introduction systems and methods
US7144532B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Oct 28, 2002 |
| Grant date | Dec 5, 2006 |
| Priority date | — |
| Expiry date | Mar 7, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T137/7762
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The present invention provides blowing agent introduction systems and methods for introducing blowing agent into polymeric foam processing systems. The methods may involve introducing one or more doses of blowing agent into polymeric material in an extruder during a plastication period of a molding cycle. Prior to introduction, a dose is confined in an accumulator which, for example, has a volume defined between an inlet valve and an outlet valve. A control system may receive inputs related to system parameters (e.g., pressure of polymeric material in extruder, axial position of screw in barrel, whether screw is rotating, and the like) and based on the inputs coordinates operation of the valves to confine and introduce the blowing agent dose(s). The introduction systems may be used in discontinuous plasticating processes, such as injection molding and blow molding, and can be particularly useful in processes that use precise quantities of blowing agent.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.