According to the Fluid Sealing Association, the trade association representing vendors offering sealing products to pump users, almost all centrifugal and rotary pumps require a sealing system to provide sealing integrity of the drive shafts carrying the impellers and protect against pumped fluid leakage and the environment outside of the wetted areas. These sealing systems range from traditional braided materials packed around the shaft to complex mechanical seal systems used in many modern pumps.
In many applications, Weir Minerals said in a recent bulletin, that the pump’s throat bushing, or throatbush, is the component that has the shortest life compared to the impeller and liners with considerable variability. Adjusting the gap between the throatbush and the impeller front shroud reduces hydraulic recirculation in the pump. This prevents localized wear on the throatbush, improves hydraulic efficiency and lowers the total ownership cost for the operator. To avoid impacting the plant’s production, these adjustments are often performed while the pump is operating. However, this can have safety implications for individuals working at the front of the pump unit.