AN IMPROVED METHOD FOR THE RESTORATION OF OID FOUNDRY SAND INTO REUSABIE QUALITY FOUNDRY SAND

摘要

A method of preparing foundry sand by measuring moisture and compressibility includes the steps of determining a set of desired characteristics for compressibility and for moisture in accordance with a particular clay content, measuring the actual compressibility in a first stage early in the processing of the foundry sand, adding moisture in accordance with the difference between the moisture for the measured compressibility and the moisture for the desired compressibility to bring the foundry sand to a predetermined value in accordance with the assumed set of characteristics, making a second measurement of the compressibility in a second stage as a countercheck near the conclusion of the processing, measuring the difference between the actual compressibility at the second stage and the desired compressibility, and employing such difference as a correcting value to adjust the calibration of the first measuring stage. If the actual compressibility measurement at the second stage is found to be out of range of predetermined maximum-minimum limits, a dosing computer adds additives such as fresh sand, clay and coal dust, and/or filtered dust in amounts calculated to bring the sand back into such range.