Promas engineers offer sieving machines [sifters]. Promas vibro sifter is multi-layer screening unit to separate mass composition of solids from solids, liquid from solid, and gradation of materials in accordance with their shapes And sizes. Promas vibro energy separator is a rapid screening device that vibrates about its center of mass. The central vertical axis being the same, vibration is accomplished by placing eccentric weights on the upper and lower ends of the motor shaft. Adjustment of the quantum and relative position of the top and bottom weights permits control of amplitude and material flow patterns. Circular screen separators are unitized machines, which impart adjustable, multiplane, mechanical, vibrations to the material being processed. The basic assembly consists of number of interchangeable discharge outlets. A motion generator [vibro motor] with double extension shaft having eccentric variable weights is rigidly mounted to the main screening assembly. The isolation of spring from support base results in a self-balancing system, which requires minimum power and avoids mechanical stress.