What happens when the front impeller clearance gets larger and larger from the front liner?
There is a condition which develops called recirculation where slurry swirls at high velocity in a circular pattern between the impeller and the liner causing very accelerated wear of both components, especially if an abrasive material is being pumped. Also, the pump loses its design head and flow is decreased. The clearance should be as close as practical. This spacing can generally be adjusted by moving the impeller forward; most pumps allow this. When one goes beyond the limit, the liner and/or impeller must be replaced.
