Device for dispensing a fluid product

1. A Venturi-based expeller dispenser, comprising:

a fluid dispenser orifice;

an air duct for air under pressure, said air duct including an upstream end and a downstream end that opens out in the proximity of the orifice;

an air expeller that is suitable for being subjected to elastic squeezing and relaxation stages, the air expeller being connected to an adapter so that, during an elastic squeezing stage, the air expeller delivers a flow of air under pressure through the adapter to the air duct until the air reaches the orifice;

a fluid channel that is connected to the air duct in the proximity of the downstream end of the fluid channel, the fluid in the channel being sucked up by the flow of air under pressure by the Venturi effect, in such a manner as to dispense a mixture of air and fluid through the dispenser orifice, wherein

the adapter including a central conduit and an air inlet valve outside and parallel to the central conduit,

a narrow neck of the air expeller being connected to a distal end of the adapter, and

the air-inlet valve being suitable for allowing outside air to enter into the air expeller during elastic relaxation stages, and for preventing air from leaving the air expeller through the air-inlet valve during elastic squeezing stages.

2. The Venturi-based expeller dispenser according to claim 1 , wherein the adapter includes a diaphragm which closes during the elastic squeezing stages and opens during the elastic relaxation stages.

3. The Venturi-based expeller dispenser according to claim 2 , wherein the diaphragm is pushed against a seat of the adapter during the elastic squeezing stages.

4. The Venturi-based expeller dispenser according to claim 1 , wherein the central conduit includes a first valve and the air-inlet valve includes a second valve, and wherein the first valve is in an open position when the second valve is closed and the second valve is in an open position when the first valve is closed.

5. A fluid dispenser device for associating with a fluid reservoir so as to form a fluid dispenser, the device comprising:

a fluid dispenser orifice;

an air duct for air under pressure, said air duct including an upstream end and a downstream end that opens out in the proximity of the orifice;

an air expeller that is suitable for being subjected to elastic squeezing and relaxation stages, the air expeller being connected to the upstream end of the air duct so that, during elastic squeezing stages, it delivers a flow of air under pressure through the air duct until it reaches the orifice; and

a fluid channel that is connected to the air duct in the proximity of its downstream end, the fluid in the channel being sucked up by the flow of air under pressure by the Venturi effect, in such a manner as to dispense a mixture of air and fluid through the dispenser orifice,

wherein the air expeller includes an opening that is provided with a connection sleeve that defines at least one portion of the air duct, the sleeve further including an incoming-air passage that is provided with an air-inlet valve that is suitable for allowing outside air to enter into the air expeller during elastic relaxation stages, and for preventing air from leaving the air expeller through the passage during elastic squeezing stages.

6. A dispenser device according to claim 5 , wherein the air-inlet valve co-operates with a valve seat in such a manner as to bear against its seat during elastic squeezing stages, the air-inlet valve being disposed in the flow of air under pressure that flows towards the air duct so as to be urged against its seat by this flow of air.

7. A dispenser device according to claim 6 , wherein the air duct and the air-inlet valve are concentrically disposed to each other.

8. A dispenser device according to claim 6 , wherein the air-inlet valve is disposed at the center of the opening, and the flow of air under pressure that flows towards the air duct is directed to the air-inlet valve, the flow of air under pressure then passing around the valve.

9. A dispenser device according to claim 6 , wherein the air-inlet valve is disposed around the flow of air under pressure.

10. A dispenser device according to claim 6 , wherein the air-inlet valve is disposed in the air duct.

11. A dispenser device according to claim 5 , wherein the connection sleeve also includes a check valve that prevents fluid from being sucked through the air duct and into the expeller during elastic relaxing stages.

12. A dispenser device according to claim 11 , the air-inlet valve and the check valve are concentrically disposed to each other.

13. A dispenser device according to claim 11 , wherein the check valve comprises a self-sealing slot that opens under the pressure of the flow of air generated during elastic squeezing stages, and that closes hermetically during elastic relaxation stages.

14. A dispenser device according to claim 11 , wherein the air-inlet valve and the check valve are constrained to move together.

15. A dispenser device according to claim 13 , wherein the air-inlet valve and the self-sealing slot are made as a single valve member, and are made out of a single material or by bi-injection of two different materials.

16. A dispenser device according to claim 14 , wherein the valve member comprises a fastener bushing that is substantially rigid and that is provided at one end with a dome that is formed with the self-sealing slot, and at the other end with a flexible annular membrane that extends outwards and that serves as an air-inlet valve.

17. A dispenser device according to claim 5 , wherein the single opening defines a minimal cross section of the air expeller.