Transportskruepar for roterende fortrengningspumpe

The invention relates to a pair of conveyor worms for rotary positive-displacement pumps, the conveyor worms of which, which are formed as a rotor and counter-rotor, rotate contactlessly in the drilling and the sides at the same speed (worm-drive pump), form loss gaps between them and have the same throat depth and pitch and symmetrical flank profiles on each side, made up with respect to their land height of a tooth base beneath the flank profile reversal point (q) and a tooth head thereabove. To provide an improvement it is proposed that the height of the loss gap (c) determined by the profile in the axial section on the pitch circle can be kept constant for a given rotor diameter (DK) by shifting the flank profile reversal point (q) as a function of a technically attainable rotor rise (H).