Weighing, measuring, signalling and checking apparatus and instruments, apparatus and instruments for conducting, switching, transforming, accumulating, regulating or controlling of electricity, namely, electromechanical controls, electrical power supplies for power operated screening rakes, step rakes, filter units, sieves, thickeners, dewatering devices, spiral pressing devices, rotary screens, screening washers, machines and devices for treatment of sand, namely, sand classifiers and sand ...