Ventilation device for a piston for a cartridge
AssigneeSulzer Chemtech AG
InventorNikolaus Brugner
Life of this patent
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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.
Claims14
A piston for a cartridge having a wall, the piston fillable with a filling mass and comprising:
- a first piston part resting sealingly against the cartridge wall;
- a second piston part;
- a valve formed by the first and second piston parts, said valve opening when a pressure is exerted on a rear side of the piston so that air trapped between the filling mass and the piston can escape,
- wherein a filter section is provided in front of the valve between the first and second piston parts with respect to a flow path of air through the valve, and the filter section has at least one narrow channel forming a penetration barrier for the filling mass.
Dependencies are inferred from the claim text.