System of diaphragm and co-acting part

1. A system including a diaphragm and co-acting part, comprising:

a co-acting part which comprises a stiff outer wall, a first annular protrusion, and a second annular protrusion, wherein the stiff outer wall comprises a generally radially extending portion of the co-acting part having radial protrusions extending therefrom and including the outermost annular wall; and

a diaphragm co-acting therewith which comprises a flexible wall of a predetermined shape and thickness, wherein the flexible wall of the diaphragm is movable along the stiff outer wall of the co-acting part, and wherein the diaphragm comprises at least two separately deformable flexible wall parts, wherein a first deformable flexible wall part is sized and configured to co-act with the first annular protrusion and a second deformable flexible wall part is sized and configured to co-act with the second annular protrusion.

2. The system of claim 1 , characterized in that the deformable flexible wall parts of the diaphragm each unroll over the stiff outer wall part of the co-acting part.

3. The system of claim 2 , wherein the stiff outer wall part of the co-acting part that co-acts with the deformable wall part of the diaphragm is formed by the radial protrusion.

4. The system of claim 3 , characterized in that the deformable wall part of the diaphragm comprises an oblique wall part, wherein the oblique wall part co-acts with the radial protrusion of the co-acting part.

5. The system of claim 4 , characterized in that the diaphragm has a substantially conical form.

6. The system of claim 1 , further comprising a valve part.

7. The system of claim 6 , characterized in that the valve part is accommodated in an opening in the diaphragm and in an opening in the co-acting part, wherein both openings form a flow channel for fluid.

8. The system of claim 7 , wherein the valve part comprises a hook which co-acts with a protrusion in the flow channel in the co-acting part.

9. A pump comprising the system of claim 1 .

10. A diaphragm for interacting with a co-acting part that has protrusions, the diaphragm comprising a flexible wall of predetermined shape and thickness;

at least two separately deformable flexible wall parts, wherein a first deformable flexible wall part is sized and configured to co-act with a first annular protrusion of co-acting part and a second deformable flexible wall part is sized and configured to co-act with a second annular protrusion of the co-acting part;

substantially vertical parts which unroll during functioning of the diaphragm; and

at least two support edges formed by substantially horizontal parts against which the first and second annular protrusions of the co-acting part will support during operation.