Trigger dispensing head with means to prevent leakage of product

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

• a frame, suitable for supporting components of the trigger dispensing, comprising a main opening in communication with an internal compartment of the bottle;
• a cylinder chamber annularly delimited by a cylinder wall having an internal surface, wherein a main vent passage is formed in the cylinder wall, putting in communication the main opening with the internal surface;
• a manually operable piston for translating between an initial rest position and a final end-of-stroke position;
• a pressure chamber in which said manually operable piston operates;
• a sleeve, delimiting said pressure chamber, at least partially housed in the cylinder chamber, comprising an annular sleeve wall, having an external surface and an internal surface;
• a suction duct suitable for putting the internal compartment of the bottle in communication with the pressure chamber;
• a dispensing duct suitable for putting the pressure chamber in communication with an external environment;
• valve means for adjusting a flow of the product from the suction duct to the pressure chamber during a suction step and from the pressure chamber to the dispensing duct during a dispensing step;
• and
• a labyrinth seal suitable for putting the main vent passage in communication with the external environment, the labyrinth seal being formed on one between the external surface of the sleeve and the internal surface of the cylinder chamber.