Ultrasonic cleaner device for an espresso coffee machine and espresso coffee machine incorporating such a cleaner device

A method of cleaning a part of a coffee machine, the coffee machine comprising a dispensing group connected to receive hot water from a boiler through a valve, the dispensing group comprising components including at least a diffuser screw and a shower screen, the diffuser screw being configured to receive the hot water through a brewing pipe from the valve and to diffuse the hot water over the shower screen, the method comprising:

• releasably attaching a body to a lower face of the dispensing group of the coffee machine, the body comprising two separate outwardly directed projections which are configured to releasably attach to the dispensing group, the body comprising a liquid reservoir defined within the body and a piezoelectric transducer defined within the body below the liquid reservoir, the body being attached in an interchangeable manner with a portafilter used in brewing espresso coffee, the liquid reservoir defining a cylindrical volume having a first depth in a reservoir depth direction, the piezoelectric transducer having a greater extent in the reservoir depth direction than the liquid reservoir;
• loading said reservoir with a liquid;
• generating an electronic signal;
• sending the electronic signal to the piezoelectric transducer so that the piezoelectric transducer receives the signal and responds by changing shape and creating a mechanical action in the liquid reservoir above the piezoelectric transducer for cleaning the components of the dispensing group;
• supplying power to the electronic piezoelectric transducer whereby the mechanical action in the liquid reservoir also cleans the valve.