Screw pump with a tapered suction-side section and a pressure-side section with a decreasing clearance

A screw rotor for a screw pump comprising:

• a rotor shaft, and
• at least two displacement elements connected with the rotor shaft, each displacement element having at least one helical protrusion,
• wherein one of the displacement elements is a suction-side displacement element, and
• wherein another one of the displacement elements is a pressure-side displacement element,
• wherein the suction-side displacement element is designed tapering in a conveying direction, and
• wherein the diameter of the pressure-side displacement element increases in the conveying direction.

A method of manufacturing a screw pump comprising:

• providing a screw rotor comprising at least two displacement elements, wherein one of the displacement elements is a suction-side displacement element, wherein the suction-side displacement element is designed tapering in a conveying direction, wherein another one of the displacement elements is a pressure-side displacement element;
• machining the pressure-side displacement element to have an increasing diameter in the conveying direction;
• and
• arranging the screw rotor inside a housing.