Method to control a hopper for a packaging machine for smoking articles

A method to control a hopper (1) for a packaging machine for smoking articles comprising:

• at least one output mouth (2), from which groups of smoking articles are cyclically extracted by means of extraction devices;
• and wherein the output mouth (2) comprises a plurality of dividing walls (7) defining veins (8), each configured to contain a vertical stack of smoking articles;
• a number of upper selection devices (13), which are designed to allow the smoking articles to move downward towards the output mouths (2) and comprise a plurality of partitions (14) defining downward channels (15) for the smoking articles;
• and a compensation chamber (17), which is interposed between the upper selection devices (13) and the veins (8), receives the smoking articles through the downward channels (15) and feeds them into the veins (8 )-;
• the method comprising:
• placing a number of sensors (18) in the area of the downward channels (15), which are configured to detect when there is an interruption in the downward movement of the smoking articles through the downward channels (15);
• determining a nominal value of the extraction speed (V) of the smoking articles;
• in case the number of obstructed downward channels (15) is smaller than a first value (n1) maintaining an extraction speed (V) equal to said nominal value;
• reducing the extraction speed (V) relative to the nominal value, in case the number of obstructed downward channels (15) is greater than the first value (n1) and smaller than or equal to a second value (n2, n3), which is greater than the first value (n1);
• and
• stopping the hopper (1), in case the number of obstructed downward channels (15) is greater than the second value (n2, n3).