Process and an apparatus for preparing a beverage under controlled pressure conditions
A process of preparing a beverage from a beverage preparation chamber includes feeding water to the preparation chamber until a first pressure is reached, interrupting the flow of water to the preparation chamber, holding the preparation chamber in a closed condition for a first time interval, opening the outlet of the preparation chamber and delivering the thus prepared beverage.
1. A process of preparing a beverage, comprising:
feeding water to a closed beverage preparation chamber until a first pressure (P 1 ) is reached, the closed beverage preparation chamber being a brewing chamber provided with a valve means;
interrupting at least once the flow of water to said preparation chamber (t pump );
maintaining said preparation chamber in a closed condition at said first pressure (P 1 ) for a pressure-holding time (t pump −t 1 );
resuming at least once said flow of water to the said preparation chamber at the end of said pressure holding time (t pump −t 1 ); and
opening said valve means of the preparation chamber to dispense the thus prepared beverage from an outlet of said preparation chamber, said opening step being carried out by a control unit via a piezoelectric valve.
2. A process according to claim 1 , wherein said pressure (P 1 ) is increased at the end of said pressure holding time (t pump −t 1 ).
3. A process according to claim 1 , wherein said pressure (P 1 ) is decreased at the end of said pressure holding time (t pump −t 1 ).
4. A process according to claim 1 , wherein said pressure (P 1 ) is decreased at least once during said pressure holding time (t pump −t 1 ).
5. A process according to claim 1 , wherein said first pressure (P 1 ) is within a range of 3 to 20 bar.
6. A process according to claim 1 , wherein said first pressure (P 1 ) is within a range of 5 to 17 bar.
7. A process according to claim 1 , wherein said pressure holding time (t pump −t 1 ) is within the range of 1 to 60 seconds.
8. A process according to claim 1 , wherein said pressure holding time (t pump −t 1 ) is within the range of 5 to 20 seconds.
9. A beverage dispensing apparatus for carrying out a process of preparing a beverage, said apparatus comprising:
a beverage preparation chamber;
means for feeding water to said preparation chamber;
means for interrupting at least once said water flow to said preparation chamber once a first pressure (P 1 ) is reached;
means for resuming said water flow after a preset time interval; and
means for opening said preparation chamber after said time interval has lapsed to provide an outlet for the prepared beverage,
wherein said preparation chamber is a brewing chamber including a piezoelectric valve to maintain said preparation chamber in a closed condition and at the first pressure (P 1 ) for a preset pressure holding time (t pump −t 1 ) before said preparation chamber is opened, and
wherein said beverage preparation chamber is a cartridge and said opening means is selected from a piercing element and a means of biasing a portion of the capsule wall.
10. An apparatus according to claim 9 , further comprising a control means to operate said interruption, resumption and opening means.
11. An apparatus according to claim 9 , further comprising pressure detecting means for detecting a pressure in the preparation chamber.
12. An apparatus according to claim 9 , further comprising a timer.
13. A beverage dispensing apparatus for carrying out a process of preparing a beverage, said apparatus comprising:
a beverage preparation chamber;
means for feeding water to said preparation chamber;
means for interrupting at least once said water flow to said preparation chamber once a first pressure (P 1 ) is reached;
means for resuming said water flow after a preset time interval; and
means for opening said preparation chamber after said time interval has lapsed to provide an outlet for the prepared beverage,
wherein said preparation chamber is a brewing chamber including a piezoelectric valve to maintain said preparation chamber in a closed condition and at the first pressure (P 1 ) for a preset pressure holding time (t pump −t 1 ) before said preparation chamber is opened, and
wherein said beverage preparation chamber is a brewing chamber and comprises at least one piston, a cylinder and a piezoelectric valve.
14. An apparatus according to claim 9 , further comprising an expansion element or a double piston system for pressure reduction.
15. An apparatus according to claim 9 , wherein the means for feeding water to said preparation chamber includes a pump.
16. An apparatus according to claim 9 , wherein the means for interrupting and the means for resuming includes a valve that is closed to interrupt said water flow and opened to resume said water flow.
17. An apparatus according to claim 9 , wherein the means for opening said preparation chamber includes a pump configured to feed the water to increase a pressure in the preparation chamber until it opens.