Method of preparing coffee infusions and machine for achieving same

A machine for preparing coffee infusions by means of a liquid under pressure, the machine being associated with a pump assembly arranged to raise the pressure of the liquid outgoing from the pump assembly up to a preset pressure value, said machine comprising:

• one or more dispensing units connected to the pump assembly, each said dispensing unit being arranged to dispense the coffee infusion;
• one or more pressure managing devices, each of said pressure managing devices being connected to a certain dispensing unit and including
• a first duct and at least one second duct that are connected in parallel, have a common outlet and are arranged to supply the dispensing unit with liquid under pressure, the liquid pressure being different in each duct,
• wherein
• said first duct is arranged between said pump assembly and said dispensing unit and comprises a valve device electronically controlled by a control unit in order to dynamically control the pressure of the liquid supplied to the dispensing unit by closing/opening said valve;
• wherein
• said at least one second duct is directly supplied with liquid by a mains delivering liquid under pressure, wherein said pressure is lower than the preset pressure value.

A device for managing pressure values of a liquid to be used for dispensing espresso coffee in a coffee machine, the device comprising

• a first duct and at least one second duct that are connected in parallel, have a common outlet into a single duct connected upstream of a heat exchanger and are arranged to supply a dispensing unit with the liquid at a first pressure and at least one second pressure lower than the first pressure,
• wherein
• said first duct is connected downstream of a pump assembly and comprises a first valve device arranged to be electronically controlled in order to turn on/off the supply of the dispensing unit with the liquid at said first pressure,
• wherein
• said at least one second duct comprises a second valve device arranged to be electronically controlled in order to turn on/off the supply of the dispensing unit with the liquid at said second pressure;
• said first duct and said at least one second duct are configured to operate in parallel when said first and said second valve device are both open.

A device for managing pressure values of a liquid to be used for dispensing espresso coffee in a coffee machine, the device comprising

• a first duct and at least one second duct that are connected in parallel, have a common outlet and are arranged to supply a dispensing unit with the liquid at a first pressure and at least one second pressure lower than the first pressure,
• wherein,
• said first duct comprises a valve device arranged to be electronically controlled in order to turn on/off the supply of the dispensing unit with the liquid at said first pressure,
• wherein
• said at least one second duct is directly supplied with liquid by a main delivering liquid at said second pressure;
• said first duct and said at least one second duct are configured to operate in parallel when said first valve device is open.

A method of preparing coffee infusions by means of a coffee machine, said method comprising, during the period required of a dispensing unit to prepare the infusion by supplying a liquid under pressure, at least the steps of:

• supplying, in a first phase or pre-brewing phase, said liquid at a first pressure;
• supplying, in a second phase or brewing phase, said liquid at a second pressure higher than or equal to said first pressure;
• supplying, in a third phase or post-brewing phase, said liquid at a third pressure lower than the second pressure;
• wherein said supply in the different phases is carried out by:
• providing a first duct and at least one second duct connected in parallel and having a common outlet connected to a dispensing unit of said coffee machine;
• dynamically controlling at least one valve device provided in said first duct.