Patent ID: 7780044

Claim:
A pump for dispensing a liquid or semi-liquid product, designed to be used, in particular, in the pharmaceutical or cosmetic field, said pump comprising a needle valve made up of a base topped by a rod, and a dispensing head manually movable on a pump body between an inactive position and a punctual product-dispensing position, said head comprising: a first cylinder forming a dosage chamber of the pump, which communicates with an intake tube by means of a check valve, a piston being slidingly mounted in said first cylinder; a second cylinder in which said needle valve is slidingly mounted, forming an exhaust valve; elastic means for respectively returning said needle valve to the position in which it blocks an orifice and the dispensing head to the inactive position; wherein said dispensing head comprises means for allowing the liquid to pass between said dosage chamber and a second chamber provided at the end of the dispensing head and communicating with the orifice of the dispensing head, said second cylinder comprising a compartment in which said elastic return means of the needle valve are housed and which is isolated from said second chamber by a watertight sealing means and in that said dispensing head comprises an inner skirt surrounding said second cylinder and an outer skirt, between which said return means of the head are placed, so that said liquid is not in contact with said return means; and wherein the pump comprises a conduit in communication with said compartment on the elastic return means side of the watertight sealing means.