Fluid delivery device

1. A device for removing impurities from a liquid, the device comprising:

a fluid path defined by a liquid reservoir, a filter having a pore size of 25 nanometers or less, and an output; and,

a pump for pressurising the liquid reservoir such that, when the output is in an open position, a pressure differential induces a flow of liquid along the fluid path through the filter to the output to remove impurities, the pump comprising:

a non-return valve through which air may be pumped into the liquid reservoir; and,

a piston shaft through which a piston head may be moved such that air is pumped through the non-return valve, wherein,

the piston shaft is substantially surrounded by the filter.

2. A device according to claim 1 , wherein the liquid reservoir, the filter, and the piston shaft are substantially cylindrical and share a common axis.

3. A device according to claim 1 , wherein the filter extends from the output along substantially an entire length of the liquid reservoir.

4. A device according to claim 1 , wherein the output comprises a flow restrictor.

5. A device according to claim 1 , wherein the output comprises a nozzle, the nozzle having an open position and a closed position.

6. A device according to claim 1 , wherein the pump is manually operable.

7. A device according to claim 1 , wherein the filter comprises a plurality of membranes.

8. A device according to claim 7 , wherein the membranes are semi-permeable and hollow.

9. A device according to claim 8 , wherein the filter membranes extend along substantially the entire length of the filter.

10. A device according to claim 1 , wherein the filter comprises an annular housing having an outer wall comprising a plurality of holes therethrough.

11. A device according to claim 10 , wherein the holes are distributed substantially across the entire length of the filter.

12. A device according to claim 1 , further comprising a visual indicator for providing an indication of the contents of the device.

13. A device according to claim 1 , further comprising a pressure regulator.

14. A device according to claim 13 , wherein the pressure regulator comprises a valve adapted to prevent the pressure in the liquid reservoir being raised above a predetermined level.

15. A device according to claim 1 , wherein the output is preceded by a secondary filter.

16. A device according to claim 15 , wherein the secondary filter is a carbon filter.

17. A fluid delivery device comprising:

a fluid path defined by a liquid reservoir, one or more membranes, and an output;

the device being configured to induce a flow of liquid along the fluid path through the one or more hydrophilic membranes to the output under a pressure differential;

and wherein the one or more hydrophilic membranes and the liquid reservoir are arranged such that liquid in the reservoir is in contact with the one or more hydrophilic membranes when the device is in substantially any orientation, and the one or more hydrophilic membranes are adapted to pass liquid in preference to gas.

18. A device according to claim 17 , further comprising means for establishing the pressure differential.

19. A device according to claim 18 , wherein the means for establishing the pressure differential is manually operative.

20. A device according to claim 19 , wherein the means for establishing the pressure differential comprises a pump.

21. A device according to claim 18 , wherein the means for establishing the pressure differential comprises a pump.

22. A device according to claim 18 , wherein the means for establishing the pressure differential comprises means to pressurise the liquid reservoir.

23. A device according to claim 17 , wherein the liquid reservoir is pre-pressurised.

24. A device according to claim 17 , wherein the liquid reservoir comprises a flexible wall such that a pressure differential may be established by squeezing the device.

25. A device according to claim 17 , wherein the one or more hydrophilic membranes are hollow tubes.

26. A device according to claim 17 , wherein the one or more hydrophilic membranes are flexible.

27. A device according to claim 17 , wherein the one or more hydrophilic membranes extend substantially across an entire length of the liquid reservoir.

28. A device according to claim 17 , wherein the one or more hydrophilic membranes are oleophilic.

29. A device according to claim 17 , wherein the one or more hydrophilic membranes are disposed within the liquid reservoir.

30. A device according to claim 17 , wherein the one or more hydrophilic membranes form a sidewall around the liquid reservoir.

31. A device according to claim 17 , wherein the device is a spray dispenser.

32. A device according to claim 17 , wherein the device is adapted for use with fluid comprising spray paint, spray deodorant, kitchen product, or perfume.

33. A device according to claim 17 , wherein the output is a nozzle having an open position and a closed position, where liquid may be extracted from the device when the nozzle is in an open position.

34. A device according to claim 17 , wherein a pore size of the hydrophilic membranes is less than or equal to 25 nanometers and the membranes act as a filter.

35. A device according to claim 34 , wherein the pore size is less than or equal to 20 nanometers.

36. A device according to claim 34 , wherein the pore size is less than or equal to 15 nanometers.

37. A device according to claim 17 , wherein the hydrophilic membranes are located within an annular housing having an outer wall comprising a plurality of holes therethrough.

38. A device according to claim 37 , wherein the holes are distributed substantially across the entire length of the housing.

39. A device according to claim 17 , wherein the output comprises a flow restrictor.