In selecting screw pumps in polder scheme projects, what are the factors that affect the design capacity of screw pumps?
Answer: The commonly used angles of inclination for screw pumps are 30°, 35° and 38°. For screw pumps of relatively high lifting head, like over 6.5 m, angle of inclination of 38° is normally used. However, for relatively lower head and high discharge requirement, angle of inclination of 30° shall be selected. In general, for a given capacity and lifting head, the screw pump diameter is smaller and its length is longer for a screw pump of 30° inclination when compared with a screw pump of 38° inclination.
To increase the discharge capacity of screw pumps, a larger number of flights should be selected. In fact, screw pumps with 2 flights are more economical that that with 3 flights in terms of efficiency and manufacturing cost. Moreover, the discharge capacity is also determined by the screw pump diameter and sizes of 300 mm to 5000 mm are available in current market.
Answer: The commonly used angles of inclination for screw pumps are 30°, 35° and 38°. For screw pumps of relatively high lifting head, like over 6.5 m, angle of inclination of 38° is normally used. However, for relatively lower head and high discharge requirement, angle of inclination of 30° shall be selected. In general, for a given capacity and lifting head, the screw pump diameter is smaller and its length is longer for a screw pump of 30° inclination when compared with a screw pump of 38° inclination.
To increase the discharge capacity of screw pumps, a larger number of flights should be selected. In fact, screw pumps with 2 flights are more economical that that with 3 flights in terms of efficiency and manufacturing cost. Moreover, the discharge capacity is also determined by the screw pump diameter and sizes of 300 mm to 5000 mm are available in current market.
