Needle valve pump for dispensing liquid product
The invention is a pump for dispensing liquid or semi-liquid product, designed and intended to be used in particular in the pharmaceutical or cosmetic field. The pump has a needle valve and a dispensing head manually movable on a pump housing between an inactive position and a dispensing position. The head includes a first cylinder forming a metering chamber for the pump, which draws in fluid from a container's reservoir by an intake tube and a check valve. A piston sealingly secured to the metering chamber pushes fluid through a passage into a second dosage chamber that is sealed from the dispensing orifice by a biased needle valve that is biased by a spring that is sealingly isolated from the second dosage chamber, the chamber that holds the elastic spring has a conduit that allows a user to test and verify that the second dosage chamber does not leak.
1. 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.
2. The pump according to claim 1 , characterised in that said passage means consist of at least one passage channel made at least partially in one wall of the cylinder, one of the ends of said channel opening into said dosage chamber and the other end of the channel opening into the second chamber.
3. The pump according to claim 1 , characterised in that said second chamber has a volume equal to one dose of product.
4. The pump according to claim 1 , characterised in that said second chamber is a chamber for chemical or biological treatment of a dose of product.
5. The pump according claim 1 , characterised in that the return means consist of a compression spring.
6. The pump according to claim 5 , characterised in that it comprises means for assembling and centering said return spring in relation to said needle valve.
7. The pump according to claim 1 , characterised in that said watertight sealing means of said compartment are formed by a projecting radial ring on an external wall of the base of the needle valve.
8. Pump according to claim 1 , wherein the conduit is selectively connected to a pneumatic measurement means for checking the seal between said compartment and said second chamber.
9. The pump according to claim 1 , characterised in that said chamber has a volume comprised between 30 and 250 μl.
10. The pump according to claim 1 , characterised in that it comprises means for support and attachment on a container of a product to be dispensed.