Ventilation device for a piston for a cartridge
US6598766B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Jan 28, 2002 |
| Grant date | Jul 29, 2003 |
| Priority date | — |
| Expiry date | Feb 1, 2022 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB05C17/00576
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
The invention relates to a ventilation device for a piston for a cartridge. The ventilation device includes a first piston part which rests sealingly against the cartridge wall and a second piston part, which forms a valve with the first piston part. The valve opens when a pressure is exerted on the rear side of the piston so that the air is trapped between the filling composition and the piston can escape. According to the invention, a filter section is provided in front of the valve, between the two piston parts, as seen from the flow path of the air through the valve. This filter section has at least one narrow channel which forms a penetration barrier for the filling mass and ensures that the valve remains dry and free of dirt.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.