Micropump for delivering liquids at low delivery rates in a push/pull operating mode

1 . A micropump for delivering liquids at low delivery rates comprising:

a reservoir chamber containing a liquid which is to be delivered, wherein the reservoir chamber is fed to a liquid sink;

a suction space comprising a saturated pump solution;

a condensation space comprising a saturated solution having a lower vapour pressure than the saturated pump solution;

a diaphragm separating the suction space and the condensation space, such that the diaphragm is permeable to water vapour and impermeable to liquid water; and

an impermeable wall separating the condensation space and the reservoir chamber, such that the water vaporizes out of the suction space into the condensation space, resulting in an increase in volume of the saturated solution in the condensation space, thereby exerting a pressure on the impermeable wall such that the liquid is driven out of the reservoir chamber.

2 . The micropump according to claim 1 , wherein the diaphragm is clamped in between housing bodies of the micropump in the region of a joint.

3 . The micropump according to claim 1 , wherein the diaphragm is embodied as a hydrophobic microfiltration flat diaphragm.

4 . The micropump according to claim 3 , wherein the flat diaphragm has a pore size in the range between 0.05 μm to 1 μm.

5 . The micropump according to claim 4 , wherein the flat diaphragm has a pore size of 0.2 μm.

6 . The micropump according to claim 1 , wherein the diaphragm is embodied as a sealed, hydrophobic solubility diaphragm.

7 . The micropump according to claim 1 , wherein the diaphragm is provided with a mechanical reinforcement.

8 . The micropump according to claim 7 , wherein the diaphragm has a mechanical reinforcement which comprises monofil reinforcement threads.

9 . The micropump according to claim 7 , wherein the diaphragm comprises a silicone film on the upper and underside.

10 . The micropump according to claim 7 , wherein the diaphragm is embodied with a spherical formation as a self-supporting structure.

11 . The micropump according to claim 9 , wherein the silicone film is manufactured from interlinked polydimethylsiloxane.

12 . The micropump according to claim 8 , wherein a current can be applied to the mechanical reinforcement at the upper side and/or the underside of the diaphragm in order to influence the delivery rate.

13 . The micropump according to claim 1 , wherein the saturated solution in the condensation space is a salt solution and is accommodated in the condensation space in the salt depot.

14 . The micropump according to claim 13 , wherein the depot contains NH 4 Cl or LiCl salts.

15 . The micropump according to claim 1 , wherein an NaCl solution is contained in the suction space.

16 . The micropump according to claim 1 , wherein the an impermeable wall is flexible and impermeable to the saturated solution in the condensation space and the liquid in the reservoir chamber.

17 . A method of for delivering liquids at low delivery rates using a micropump, the method comprising:

containing a liquid to be delivered in a reservoir chamber, wherein the reservoir chamber is fed to a liquid sink;

pumping a saturated pump solution into a suction space;

pumping a saturated solution having a lower vapour pressure than the saturated pump solution into a condensation space;

separating the suction space and the condensation space by a diaphragm, such that the diaphragm is permeable to water vapour and impermeable to liquid water;

separating the condensation space and the reservoir chamber by an impermeable wall;

vaporizing water out of the suction space into the condensation space through the diaphragm;

increasing the volume of the saturated solution in the condensation space;

exerting a pressure on the impermeable wall; and

driving the liquid out of the reservoir chamber.