Unit for the preparation of a foamy beverage from a capsule and an opening plunger

1. A unit for preparation of a foamy beverage from a soluble product, the unit comprising:

a collecting device with a seat arranged to receive a disposable capsule containing the soluble product, with the capsule containing at least one inlet port for a diluting fluid introduced into the capsule, at least one outlet port for delivery of a beverage provided by thorough mixing of the soluble product and the diluting fluid, and a bottom wall; and

a throttling arrangement provided by an engaging surface of a plunger that is operatively associated with the outlet port of the capsule;

wherein the engaging surface of the plunger is positioned and arranged outside of the capsule before the diluting fluid enters into the capsule, with the throttling arrangement created as diluting fluid is urged to enter the capsule by expansion of the capsule bottom wall and by forcing the engaging surface of the plunger to snugly fit through the outlet port, thereby limiting the introduction of the plunger inside the capsule to the limited displacement of the bottom wall as a result of its deformation under pressure and wherein the plunger is connected to a control mechanism that withdraws the plunger after the pressure in the capsule has been maintained a sufficient time to enable the soluble product and the diluting fluid to properly mix together to form the beverage.

2. Unit according to claim 1 wherein the plunger extends into the capsule through the outlet port by ho more than 3 mm of the plunger length.

3. Unit according to claim 1 , wherein the plunger extends into the capsule by a maximum length of 2 mm from the capsule bottom wall.

4. Unit according to claim 1 , wherein the bottom wall is made of a rigid or semi-rigid plastic material.

5. Unit according to claim 1 , wherein the control mechanism operates after a pressure of at least 2 bars during a period of at least 5 seconds has been maintained in the capsule.

6. Unit according to claim 1 , wherein the engaging surface that enters the capsule is positioned by contact with a supporting member having a surface of larger section than that of the outlet port, with the supporting member positioned on the capsule bottom wall.

7. Unit according to claim 6 , wherein the surface of the supporting member has a dome shape to allow high shear force fluid discharge without blocking fluid flow.

8. Unit according claim 7 , wherein the dome shape includes at least one channel of 0.01 to 1 square mm.

9. Unit according claim 7 , wherein the dome shape includes a textured or roughened surface which forms random flow channels with the capsule bottom through which the beverage can flow.

10. Unit according to claim 1 , wherein the engaging surface of the plunger has a section that is at least the same as or larger than that of the outlet port to form an interference fit between the outlet port and the plunger.

11. Unit according to claim 1 , wherein the collecting device further comprises means for supporting the capsule fitted in the seat, with the supporting means arranged to maintain the engaging surface of the plunger outside the outlet port before the diluting fluid enters the capsule.

12. Unit according to claim 1 , wherein the engaging surface of the plunger and the outlet port each have essentially the same sectional profile.

13. Unit according to claim 1 , wherein the engaging surface of the plunger is substantially cylindrical.