Abstract: To avoid areas of slow moving or stagnant polymer in a gear pump feeding from an extruder to a die, the inlet port (7) has its cross-section changing progressively from that of the outlet (10) of the extruder to a slot section (11) at the demeshing region of the gear teeth, the slot section having a breadth at least equal to the breadth of the gears (3, 4) and a height between one and four times the gear teeth height, and the outlet port (8) preferably changes progressively from a similar slot section (16) at the meshing region of the gear teeth to the cross-section of the inlet (17) of the die.