Device for heating and frothing milk

1 . A device for heating and frothing milk, usable for preparing a hot beverage, comprising

a steam generator,

a jet pump operated by steam, said jet pump comprising a steam inlet through which pressurized steam is injectable into the jet pump to generate a steam jet, a first suction inlet and a second suction inlet through which respective fluids are drivable by the steam jet into the jet pump to mix with said steam jet, wherein the first suction inlet is configured to connect to a milk reservoir, and

a steam valve connected to the steam inlet of the jet pump and switchable between a first position in which the steam inlet of the jet pump is in fluid communication with the steam generator, and a second position in which the steam inlet of the jet pump is shut off from the steam generator,

said device further comprising

an air inlet connectable or connected to the second suction inlet of the jet pump for suction of air into the jet pump, and

a bypass valve connected to the second suction inlet of the jet pump and having a bypass inlet connected to the steam generator in parallel with the steam inlet of the jet pump, said bypass valve being switchable between a first position in which the second suction inlet of the jet pump is shut off from the steam generator, and a second position in which the second suction inlet of the jet pump is in fluid communication with the bypass inlet of the bypass valve for suction of steam into the jet pump through the second suction inlet.

2 . The device of claim 1 , wherein the air inlet is incorporated into the bypass valve, wherein in the first position of the bypass valve the second suction inlet of the jet pump is in fluid communication with the air inlet for drawing air into the jet pump, and wherein in the second position of the bypass valve the second suction inlet of the jet pump is shut off from the air inlet.

3 . The device of claim 1 , wherein the air inlet and the bypass valve are connected to the second suction inlet of the jet pump separately from each other.

4 . The device of claim 1 , wherein an inlet of the steam valve is connected to the steam generator.

5 . The device of claim 1 , wherein the bypass inlet of the bypass valve and the steam inlet of the jet pump are both connected to an outlet of the steam valve.

6 . The device of claim 1 , wherein the steam inlet of the jet pump is connected to an outlet of the steam valve and the bypass inlet of the bypass valve is connected to the steam generator, upstream of the steam valve.

7 . The device of claim 1 , further comprising a brewing valve having an inlet connected to the steam generator and an outlet connected to a brewing chamber for preparing a brewed beverage, said brewing valve being switchable between a first position in which the brewing chamber is in fluid communication with the steam generator, and a second position in which the brewing chamber is shut off from the steam generator.

8 . The device of claim 1 , further comprising an electronic control unit (ECU) configured to control and coordinate, according to predetermined procedures, the steam valve and the bypass valve as a function of instruction signals provided to the ECU.

9 . The device of claim 8 , wherein the ECU is configured to adjust a dwell time ΔT 1 of the bypass valve in the first position and a dwell time ΔT 2 of the bypass valve in the second position as a function of a recipe provided to the ECU.

10 . The device of claim 1 , wherein the hot beverage is cappuccino or hot milk.