Device for cutting hollow fiber membranes

1 . A device for cutting a single hollow fiber membrane comprising (i) a transport unit and (ii) a cutting unit comprising at least one blade,

wherein the transport unit is configured to feed a wet continuous filament of a hollow fiber membrane to the cutting unit, wherein the hollow fiber membrane has an outer diameter larger than 3 mm and smaller than 4.5 mm, and wherein the ratio of inner diameter to wall thickness of the membrane is larger than 10,

wherein the transport unit comprises a first roller, a second roller, a third roller, and a four roller, wherein each of the four rollers feature a groove having a profile with a curvature matching the curvature of the perimeter of the hollow fiber membrane, and wherein each of the four rollers comprises a center,

wherein the first roller and the second roller are each stationary, and wherein a line connecting the center of the first roller and the center of the second roller defines a horizontal direction,

wherein the center of the third roller is located above the center of the second roller, such that the perimeters of the second roller and the third roller are flush at the outlet side of the transport unit,

wherein the first roller and the fourth roller have the same diameter, and wherein the center of the fourth roller is located between and above the center of the first and the center of the second roller, and

wherein the configuration of the transport unit can be changed between a threading configuration and a working configuration, and wherein in the working configuration the center of the fourth roller is on the line connecting the center of the first roller and the center of the second roller.

2 . The device of claim 1 , wherein the first roller, the second roller and the fourth roller have the same diameter.

3 . The device of claim 2 , wherein the third roller has a smaller diameter than the first roller, the second roller, and the fourth roller.

4 . The device of claim 1 , wherein the center of the fourth roller is located between the center of the first roller and the center of the second roller.

5 . The device of claim 1 , wherein

i) in the threading configuration, the third roller and the fourth roller have been moved into an upper position, in which the third roller and the fourth roller do not touch a continuous filament of a hollow fiber membrane located on the first roller and the second roller of the transport unit, which allows for threading a continuous filament of a hollow fiber membrane into the transport unit; and

ii) in the working configuration, the third roller and the fourth roller have been moved downward into a lower position, in which the third roller and the fourth roller touch the continuous filament located on the first roller and the second roller, for transporting the continuous filament and feeding it to the cutting unit.

6 . The device of claim 1 , wherein the cutting unit comprises a plurality of blades mounted on a rotating wheel, the axis of the rotating wheel being parallel to the longitudinal axis of the continuous filament of a hollow fiber membrane.

7 . The device of claim 1 , wherein the third roller and the fourth roller are moveable in a direction perpendicular to the horizontal direction.