Patent ID: 8365966

Claim:
A pump for dispensing a liquid or semi-liquid product, comprising: a pump body; a dispensing head movable in the pump body between an inactive position and a product-dispensing position, said dispensing head comprising: a cylinder including a dosage chamber, said dosage chamber communicating with a liquid intake tube via an intake valve, said cylinder being slidingly mounted in said pump body; a channel allowing the product or air to pass from the dosage chamber to an ejection orifice; an exhaust valve made up of a rod and comprising a peripheral shoulder capable of coming to a rest against a sealing seat of the cylinder to seal the channel, the channel being opened by separating the shoulder from the seat of the cylinder; and a push button fitted onto the cylinder by a first skirt, the push button designed to activate the axial movement of the cylinder; a spring for returning the dispensing head to the inactive position housed between the first skirt and a second skirt outside the first skirt; wherein said sealing seat is arranged in the cylinder and the channel is arranged between an outer wall of the cylinder and the inner wall of the first skirt; and wherein the exhaust valve is opened by stopping a bottom end of the rod against the intake valve during priming.