Method to improve suction efficiency of flow demand pump

摘要

A centrifugal immersion pump, unable to pump efficiently at low fluid levels, due to air in the region of the impeller, is provided with a bleed tube from the centre of the rear of the impeller to outside the pump body. The submersible pump is provided with a motor-driven impeller (10) comprising a disc-shaped rear portion (9) and spiral blades (8). Liquid is drawn through an opening 16) and discharged through a tangential pipe (20). Pump efficiency may be limited by entry of dirt or air, due to low liquid level. An auxiliary impeller (15) at the fluid entry inhibits dirt particles and a tube (1) allows air or other gas to escape.