Patent ID: 9357871
Filing Date: 2016-06-07
CPC Classification: A23F,A47J

Claim Text:
1. A method for controlling the dispensing pressure in a coffee machine for producing and dispensing coffee-based beverages from a plurality of dispensing devices, each dispensing device comprising a filter unit configured for containing coffee powder, the method comprising: providing a hydraulic circuit in fluid communication with the plurality of dispensing devices, the hydraulic circuit comprising a corresponding plurality of supply ducts connected to the plurality of dispensing devices; supplying pressurized water to the hydraulic circuit by means of a pump; providing a corresponding plurality of variable-flow valves in the plurality of supply ducts, each variable-flow valve being constructed to vary the flow of water through its respective supply duct to a dispensing device connected to the supply duct, each variable-flow valve being actuatable by a respective electronic drive which controls the flow rate of water output from the variable-flow valve and which is connected to a control unit so that each variable-flow valve can be operated independently one from another to control the flow rate of water output; providing a corresponding plurality of pressure sensors in the plurality of supply ducts, the plurality of pressure sensors being connected to the control unit; supplying from one of the variable-flow valves a predetermined quantity of water to its respective dispensing device corresponding to a nominal dispensing pressure value for the respective dispensing device; detecting the dispensing pressure of the respective dispensing device by means of the pressure sensor in the respective supply duct connected to the respective dispensing device; and if the detected dispensing pressure deviates from the nominal dispensing pressure value for the respective dispensing device, adjusting the flow rate of water supplied by the respective variable-flow valve connected to the respective dispensing device while continuing the flow of water through the respective dispensing device to adjust the detected pressure value to the nominal pressure value; whereby the variable-flow valves can independently control the dispensing pressure of each dispensing device without requiring any change in the flow of pressurized water being supplied by the pump, wherein the detected dispensing pressure of each dispensing device is dependent on grain size of coffee powder contained in each dispensing device, and the variable-flow valve corresponding to each dispensing device independently controls the dispensing pressure of its respective dispensing device based on the grain size of the coffee contained in the dispensing device.