R&W worked with the plant process engineering to develop PLC automation upgrades to replace existing electro-mechanical sand mulling control equipment.
This equipment blends reclaimed sands with water and bonding agents to create molding sand for the casting operations. The system now incorporates reclaim sand temperature and/or moisture measurements to calculate water addition with each batch. Water addition is now performed with accurate magnetic flow metering to an accuracy of 0.1 gallons per batch. Mullors No. 2 and 4 were the first ones installed with the new PLC based automaton. Subsequently in 2009-2010 Mullors 1 and 3 were automated in a similar manner. However, Mullor No. 1 produces facing sand formulations and uses multiple sand sources for each batch. Therefore, this system was provided with a recipe based formula system to allow operators to create facing sand formulations and to be able to rapidly switch from one to another. All Mullor batching systems produce a final casting sand batch every 2-4 minutes depending on mulling time. All plant sand mulling operations are now fully automated with plant PLC’s.