Trigger dispensing device with means to avoid the loss of product

A trigger dispensing head applicable to a bottle of a trigger dispensing device, comprising:

• a cylinder chamber annularly delimited by a cylinder wall having an inner surface;
• a main vent passageway passing through the cylinder wall and adapted to put an inner compartment of the bottle in communication with the inner surface of the cylinder wall;
• a sleeve at least partially received in the cylinder chamber, comprising an annular sleeve wall having an outer surface and an inner surface in communication with an external environment, and a secondary vent passageway passing through the annular sleeve wall;
• an axially slidable piston sealed inside the sleeve between an initial rest position and a final stroke-end position, comprising an annular piston seal that forms a pressure chamber;
• and
• a suction duct adapted to put the inner compartment of the bottle in communication with the pressure chamber and a dispensing duct adapted to put the pressure chamber in communication with an external environment;
• wherein said sleeve is rotatable by a user between an angular working position, in which the main vent passageway is in fluid communication with the secondary vent passageway, and an angular rest position, in which the main vent passageway is fluidically separated from the secondary vent passageway.