Brewing unit for automatic beverage dispensers comprising in particular a boiler

Infusion unit for an automatic dispenser of beverages made from powdered coffee or the like and comprising a body (10) with a longitudinal axis V enclosing an infusion chamber (31) having a bottom (11) and a mouth (15), comprising a filter plate (36) and adapted to receive a pressure piston (62) mounted movably along the axis (V) by means of a drive mechanism (59), pumping means (40) adapted to create a circulation of water and infusion, as well as a boiler (60) adapted to boil the water for the preparation of the infusion in the chamber (31),

• characterized in that the boiler (60) and the body (10) are formed of a single piece of heat conductive material which contains an electric heating resistance (26), channels (30) for passage and heating of the water whose inlets (33) are connected to a cold water reservoir (R) and whose ends (33′) open through the bottom (11) of the infusion chamber (31), and the pressure piston (62) has a conduit (42) for the passage of the infusion opening through an outlet opening (42b), whilst the pumping means (40) are adapted to create an ascending circulation of water in the infusion chamber (31) toward the conduit (42) when the pressure piston (62) closes the chamber (31).