Emulsifying device and method to produce frothed milk and the like
The device comprises: a milk feed pipe ( 11 ); an air inlet duct ( 15 ); a pressurized steam feed pipe ( 17 ); an emulsion chamber ( 41 ), in which milk and air, drawn by means of the pressurized steam, are mixed and emulsified; along the steam feed pipe ( 17 ), a valve to place the steam feed pipe in communication with the outside and to cause emptying of the milk feed pipe.
1. An emulsifying device to produce frothed milk, comprising:
an emulsion chamber;
a volume in communication with the emulsion chamber;
a milk reservoir;
a milk channel in fluid communication between the volume and the milk reservoir for drawing milk from the milk reservoir;
an air inlet duct having an opening for drawing air and in fluid communication with the volume and the milk channel;
a steam feed pipe configured to feed pressurized steam into the emulsion chamber when pressure inside the steam feed pipe is above a first pressure value above ambient pressure, wherein feeding of the pressurized steam into the emulsion chamber draws milk and air to be mixed and emulsified; and
a pressure controlled valve coupled along the steam feed pipe and configured to respond to the pressure inside the steam feed pipe to selectively control inflow of ambient air from the pressure controlled valve to the milk reservoir, through a portion of the steam feed pipe and the milk channel to empty the milk from the milk channel back to the milk reservoir in response to the pressure inside the steam feed pipe falling below a second pressure value above ambient pressure while there is still residual pressurized steam present in the steam feed pipe, and further configured to stop the inflow of the ambient air from the pressure controlled valve in response to the pressure inside the steam feed pipe rising above the first pressure value.
2. The device according to claim 1 , wherein the pressure controlled valve is configured to automatically control the inflow of the ambient air.
3. The device according to claim 2 , wherein opening and closing of the pressure controlled valve are automatically controlled by the pressure in the steam feed pipe.
4. The device according to claim 3 , wherein the pressure controlled valve is configured to automatically close to feed the pressurized steam into the emulsion chamber when the pressure inside the steam feed pipe reaches the first pressure value above ambient pressure, and to automatically open to enable the inflow of the ambient air from the pressure controlled valve when the pressure inside the steam feed pipe reaches the second pressure value above ambient pressure, the second pressure value is less than the first pressure value.
5. The device according to claim 1 , wherein the pressure controlled valve is configured to operate with the first pressure value being selected from one of between 60 and 150 mbar, between 80 and 120 mbar, and between 90 and 100 mbar of overpressure in relation to ambient pressure.
6. The device according to claim 5 , wherein the pressure controlled valve is configured to operate with the second pressure value being selected from one of between 5 and 45 mbar, between 15 and 40 mbar, and between 20 and 40 mbar of overpressure in relation to ambient pressure.
7. The device according to claim 1 , further comprising a Venturi tube connected between the steam feed pipe and the emulsion chamber and between the volume and the emulsion chamber, wherein the air inlet duct and the milk channel converge in the volume, the pressurized steam from the steam feed pipe producing, in the Venturi tube, a vacuum which draws the milk and air through the Venturi tube into the emulsion chamber.
8. The device according to claim 7 , wherein the emulsion chamber comprises a cross section substantially larger than the Venturi tube.
9. The device according to claim 7 , wherein the emulsion chamber includes a discharge pipe.
10. A method to produce emulsified milk, the method comprising acts of:
providing a steam feed pipe having a pressure controlled valve coupled there along, the steam feed pipe being connected to an emulsion chamber, and an air inlet duct connected with a milk channel and a volume that is also in communication with the emulsion chamber;
feeding pressurized steam through the steam feed pipe into the emulsion chamber when pressure inside the steam feed pipe is above a first value above ambient pressure;
emulsifying milk using the pressurized steam to draw milk from a milk reservoir through the milk channel and draw air through the air inlet duct respectively into the volume;
dispensing the emulsified milk from the emulsion chamber; and
after dispensing
reducing the pressure inside the steam feed pipe to a second pressure above ambient pressure and below the first value,
opening the pressure controlled valve automatically responsive to the reduction of the pressure enabling an inflow of ambient air from the pressure controlled valve, through a portion of the steam feed pipe and the milk channel to the milk reservoir while there is still residual pressurized steam present in the steam feed pipe above ambient pressure, and
discharging the milk from the milk channel to the milk reservoir automatically responsive to the inflow of the ambient air.
11. The device according to claim 4 , wherein the second pressure value is selected from one of between 5 and 45 mbar, between 15 and 40 mbar, and between 20 and 40 mbar of overpressure in relation to the ambient pressure.
12. The device according to claim 1 , further comprising a stem removably positioned inside the air inlet duct for controlling air access to the milk channel.
13. The device according to claim 1 , wherein the pressure controlled valve is configured to enable the inflow of the ambient air into the steam feed pipe before flow of the pressurized steam towards the emulsion chamber terminates.
14. The method of claim 10 , wherein the act of opening of the pressure controlled valve enables the inflow of the ambient air into the steam feed pipe before flow of the pressurized steam towards the emulsion chamber terminates.