About 10% of molten metal pumps are used exclusively for maintenance applications. It is not uncommon to use a maintenance pump once every year to eighteen months. Long term storage of a pump, especially a pump that has been exposed to molten metal, requires special considerations.
Maintenance pumps tend to undergo rougher duty than continuous circulation and transfer pumps. As the furnace is emptied, the pump base is lowered to bottom where contamination accumulates. This can be especially rough on impellers and shafts.
- Emergency Bail-Out Pump – Power outages and emergency furnace maintenance sometime require immediate pump-outs. Ideally, an emergency pump is maintained in a pre-heat station and can be ready to use in 15 minutes or less.
- Planned Maintenance – Planned maintenance allows scheduling of the pump preparation well in advance. This means that the pump does not need to be stored in a preheat station.
- Multiple Metals – Maintenance pumps are frequently used in with more than one metal type. For instance, some foundries have both aluminum and zinc or magnesium and aluminum furnaces in the same facility. This can create special considerations for maintenance pumps.
In between uses, the pump will need to be serviced and stored to ensure it is ready for future maintenance needs.