Brewing unit for coffee machine for preparing espresso, has piston and connecting plate comprising seal or sealing lip that forms lip sealing rings, where sealing lip is pressed with chamber by operating pressure at cylinder wall

摘要

The unit has a brewing chamber (5) for receiving coffee ground. The brewing chamber comprises a connector for supply of hot water (6) and for discharge of a filtrate (7). A piston (2) is provided for sealing a coffee ground. The piston and a connecting plate (8) comprise a seal or sealing lip that forms lip sealing rings (3). The sealing lip is supported with the brewing chamber charged with pressure under small pretension at a cylinder wall (1). The sealing lip is pressed with the chamber by an operating pressure at the cylinder wall.