Screw pump, screw rotor, method of manufacturing a screw rotor, and use of a screw pump or a screw rotor

A screw pump 100 comprising a housing defining a chamber 62 and two screw rotors 10. Wherein each screw rotor comprises a rotor shaft 11 and at least two displacement elements 12, 14 connected with the rotor shaft. Each displacement element having at least one helical protrusion 36, 50. One of the displacement elements is a suction-side displacement element 12 arranged in a suction-side section 64 of the chamber. Another one of the displacement elements is a pressure-side displacement element 14 arranged in a pressure-side section 68 of the chamber. The suction-side displacement element 12 is designed tapering in the conveying direction 22. The clearance between the pressure-side displacement element and the pressure-side section of the chamber at least partly decreases in the conveying direction. Furthermore, a screw rotor, a method of manufacturing a screw rotor and a use of a screw pump or a screw rotor.