6.8.1 Measure the clearanceDependin

6.8.1 Measure the clearanceDepending on the type of media that is being pumped the pump will more or less beexposed to wear, mainly in the gap between the propeller blades and the wear ring/pump housing.The clearance between the propeller blades and the pump housing/wear ring willincrease. The effect of this is that the capacity as well as the efficiency will drop. It shouldbe noted that these effects are not linearly proportional to the size of the clearance, butprogressive.Operating the pump when the wear ring clearance has reached or exceeded theclearance threshold will result in a loss of capacity (flow) and pump efficiency.It is therefore recommended that the clearance be checked at routine inspections andworn parts be replaced as necessary. If the measured wear ring clearance exceeds thecritical limit, then we recommend that the efficiency drop be evaluated and replacementof worn parts be considered.1. Measure the clearance between the propeller blades and the wear ring in a few placesto get an average value.The clearance can vary slightly as the propeller might not be perfectly centered due tomanufacturing tolerances.1