Patent ID: 8770092
Filing Date: 2014-07-08
Classification: A47J

Abstract:
1. A brewing unit for a coffee machine for brewing a coffee powder portion, comprising: a housing of the brewing unit, an upper plunger having a beverage outlet, the upper plunger is fixedly connected with the housing of the brewing unit, a sleeve, open at a top of the sleeve and closed at a bottom of the sleeve by a base, the sleeve configured to receive the coffee powder portion, a brewing plunger for compressing the coffee powder portion in a brewing chamber, the sleeve and the brewing plunger being movably and pivotally arranged in the housing of the brewing unit, mechanical actuating members for: the brewing plunger being mechanically and hydraulically guided in the sleeve so as to displace relative to the sleeve, the upper plunger being maintained stationary relative to the housing of the brewing unit while the sleeve and the brewing plunger move from the filling position to the brewing position and to the cleaning position; a lower chamber space, where a hot water supply duct ends fixedly connected to the sleeve, said lower chamber space provided in the sleeve between the base of the sleeve and a bottom face of the brewing plunger, the brewing plunger having a plunger duct for hot water, the plunger duct is equipped with an inlet valve and connects the lower chamber space with the brewing chamber, wherein, by supplying pressurised hot water through the supply duct, an overpressure can be created in the lower chamber space and the brewing plunger can be hydraulically pushed in the direction of the brewing chamber until the inlet valve opens and the hot water flows into the brewing chamber; wherein the upper plunger fixedly connected with the housing of the brewing unit further comprises an outlet valve configured to open when a predetermined pressure is attained in the brewing chamber whereby a brewed beverage can flow out through the outlet only when the outlet valve opens.