Laundry washing machine equipped with a microparticles filter device and method for controlling said machine

A laundry washing machine comprising:

• an outer cabinet;
• a washing tub containing a washing drum suited to receive the laundry to be washed;
• a liquid supply system suitable to convey a liquid to the washing tub;
• a draining system fluidly arranged downstream the washing tub and comprising a draining pump that has an inlet fluidly connected to the washing tub and an outlet fluidly connected to an outlet pipe to drain liquid outside the outer cabinet;
• and
• a microparticles filter device arranged downstream the draining pump, the microparticles filter device comprising:
• a housing body;
• an inlet for liquid to be filtered;
• a filtering chamber housed in the housing body, the filtering chamber comprising a microparticles filter element having a filtering surface on which microparticles accumulate while the liquid flows therethrough;
• and
• a first outlet for delivering filtered liquid towards the outlet pipe;
• wherein the microparticles filter device further comprises a second outlet that is fluidly connected to the draining system upstream the draining pump and arranged at a higher vertical level with respect to the draining pump such that a portion of the filtered liquid is cyclically circulated through the microparticles filter device during the operation of the draining pump or returned towards the draining system when the draining pump is not operating.