Group head for espresso machine

Claims

1. A group head for an espresso machine comprising a group head bracket for releasably engaging a portafilter that holds a ground coffee tablet in a filter basket for dispensing espresso coffee; a channel for receiving a flow of water to the portafilter; and A heater installed in the group head to heat the water flow entering the portafilter.

2. The head of the group according to claim 1, further comprising a flow diffuser adjacent to the heater for defining a space for distributing the flow of water from the channel over the surface of the heater to improve conductive heating.

3. The head of the group according to claim 2, in which the diffuser has a plurality of channels for directing the flow of water along the surface of the heater, and the channels have channel walls that abut against the surface of the heater for heat conduction into the diffuser.

4. The head of the group according to claim 3, in which each of the channels is in fluid communication with a channel for receiving a flow of water, and each of the channels has at least one outlet end for fluid communication with a portafilter.

5. The head of the group according to claim 4, further comprising a mesh located between the outlet ends of the channels and the portafilter, wherein the outlet ends are located such that the flow of water through the mesh to the portafilter has the required distribution through the tablet of ground coffee.

6. A group head according to any one of paragraphs 2-5, in which the diffuser is made of a corrosion-resistant material with a high specific heat capacity.

7. The group head according to claim 1, in which the heater is installed in the group head bracket for heat conduction from the heater to the group head bracket.

8. The group head according to claim 7, in which the releasable engagement between the group head bracket and the portafilter is configured to allow heat conduction from the group head bracket to the portafilter.

9. A head of a group according to any one of paragraphs 1-8, in which the heater is a resistive heater with a conductive path made of an electrically resistive material.

10. The head of the group according to claim 9, in which the resistive heater is configured to be adjustable for heating the water flow to a predetermined temperature.

11. The head of the group according to claim 10, in which the set temperature is a user-selected temperature.

12. A group head according to any one of paragraphs 9-11, further comprising a temperature sensor for feedback control of the resistive heater.

13. A head of a group according to any one of paragraphs 9-12, in which the resistive heater is a thick-film heater with an electrically resistive material applied in the form of a thick film onto a substrate.

14. The head of the group according to claim 11, in which the thick film heater surrounds at least one section of the channel.

15. A head of the group according to claim 13 or 14, in which the thick film heater is a disk arranged so that during use the disk extends in a plane substantially parallel to the upper surface of the tablet.

16. The head of the group according to claim 15, in which the channel has an outlet end in the center of the disk, and the diffuser channels are designed to allow radial distribution of the water flow over the surface of the disk.

17. A group head according to any one of paragraphs 13-16, in which the thick-film heater is designed with the possibility of heating the water flow through the group head to a temperature of from 89°C to 96°C.

18. The head of the group according to any one of paragraphs. 13-16, in which the thick-film heater is designed to heat the flow of water taken from the reservoir inside the espresso machine to 89-96°C in less than 10 seconds from the moment the thick-film heater is activated.

19. A group head according to any one of claims 1-18, wherein the group head comprises a chamber defined by the inner walls of the group head, wherein the chamber has an opening for receiving a portafilter, and wherein the heater is mounted on the chamber.

20. An espresso machine comprising a group head according to any one of claims 1-19.

21. A method for producing espresso coffee, comprising the following steps: placing a tablet of ground coffee inside the portafilter filter basket; attaching a portafilter to the group head of an espresso machine, the group head having a heater and a channel for the flow of water to the portafilter; ensuring the flow of water through the channel to the ground coffee tablet; heating the water flow through the group head by means of a heater.

22. The method of claim 21, wherein the heater is a resistive heater having a conductive path made of an electrically resistive material.

23. The method according to claim 22, further comprising the step of regulating the electrical power of the resistive heater for heating the water flow from the head of the group to a predetermined temperature.

24. The method according to claim 23, wherein the set temperature is selected by the user.

25. The method according to any one of paragraphs 21-24, further comprising the step of providing a temperature sensor for feedback control of the resistive heater by a control unit within the espresso machine.

26. The method according to any one of paragraphs 21-25, in which the heater is configured to surround at least one section of the channel.

27. The method according to any one of paragraphs 21-26, in which the resistive heater is a thick-film heater with an electrically resistive material applied as a thick film to a substrate.

28. The method according to claim 27, wherein the thick-film heater is in the form of a disk extending in a plane substantially parallel to the upper surface of the tablet.

29. The method according to any one of paragraphs 21-28, further comprising the step of providing the head of the group with a flow diffuser adjacent to the heater to define a space for distributing the flow of water from the channel over the surface of the heater to enhance conductive heating.

30. The method of claim 29, wherein the diffuser has a plurality of channels for directing the flow of water over the surface of the heater, and the channels have channel walls that abut the surface of the heater for heat conduction into the diffuser.

31. The method of claim 30, wherein each of the channels is in fluid communication with a channel for receiving a flow of water, and each of the channels has at least one outlet end for fluid communication with a portafilter.

32. The method of claim 31, further comprising the steps of providing a mesh between the outlet ends of the channels and the portafilter and arranging the outlet ends such that the flow of water entering through the mesh into the portafilter has the desired distribution through the ground coffee tablet.

33. The method according to any one of paragraphs 29-32, in which the diffuser is made of a corrosion-resistant material with a high specific heat capacity.

34. The method according to any one of paragraphs 21-33, further comprising the step of providing a group head bracket for mounting the group head on the espresso machine, wherein the heater is mounted in the group head bracket for conducting heat from the heater to the group head bracket.

35. The method of claim 34, wherein the releasable engagement between the group head bracket and the portafilter is configured to conduct heat from the group head bracket to the portafilter.

36. The method according to any one of paragraphs 21-35, further comprising the step of adjusting the thick-film heater to heat the water flowing from the group head to a temperature of 89-96°C.

37. The method of claim 36, further comprising the step of adjusting the thick film heater to heat water flowing through the group head to at least 89°C in less than 10 seconds from the activation of the thick film heater.