Blowing agent metering system
US6616434B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 10, 2000 |
| Grant date | Sep 9, 2003 |
| Priority date | — |
| Expiry date | Dec 19, 2020 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C2948/92914
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
The invention provides a blowing agent metering system and method for use in polymeric foam processing. The system may be used to control the rate of introduction of blowing agent into polymeric material in a processing apparatus to form a mixture having the desired blowing agent weight percentage. The metering system includes a restriction orifice which is positioned in a pathway between a blowing agent source and a blowing agent port within a foam processing apparatus. The metering system measures the pressure differential as blowing agent flows across the restriction orifice from the source to the port and may also measure the temperature of the blowing agent at one or more locations. Using a pre-determined relationship between the flow rate, the orifice dimensions (e.g., length, diameter) and the measured variables (e.g., pressure differential, temperature), a controller of the system adjusts the pressure upstream of the restriction orifice in response to inputs of the measured variables to maintain a pressure differential across the orifice that provides the desired blowing agent flow rate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.