Principles of design.

The Isodynamic^® Separator consists essentially of an electromagnet having two long pole pieces shaped to a special contour (shown in simplified form in the sketch below) with a long narrow air gap between them. Materials to be separated are fed into one end of the magnetic field (1) and travel through its entire length. The more strongly paramagnetic particles are urged toward the narrow side of the gap (2). The grains are intercepted by a dividing edge which directs the two fractions into separate containers.

    The magnetic system is carried on a universal mounting so that it can be oriented in any direction with respect to gravity. The system is oriented with the gap in the vertical position when material is to be fed by free fall. When material is to be processed by the inclined chute mode, the system is oriented so that one component of gravity is opposed to magnetic force and another component of gravity urges the material down the chute. The whole is mounted on a massive cast aluminum base with leveling feet, and to facilitate leveling, a spirit level is set into the magnet system.    

     Power is supplied to the magnet coils of the separator by a model EMS-150 regulated power supply. It provides linked regulation of direct current and voltage. With the current regulation active, as resistance increases with heating of the coils, voltage increases automatically to maintain the selected current. Current can be adjusted from zero to over 2 Amperes at start-up. The power supply will maintain 1.8 Amperes indefinitely at ambient temperatures up to approximately 32ºC (90ºF). At 1.8 Amperes the magnetic field strength in the narrowest part of the gap is approximately 20 KiloGauss.

    The coaxial vibrator for the inclined chute is controlled by a ten-turn potentiometer in one section of an external vibrator control.

    The Isodynamic Separator makes sensitive separations of minerals or other grains according to susceptibility, even of materials not usually thought of as magnetic. Magnetic force per unit volume on particles of like susceptibility is constant across the width of the operating space at the midplane between the pole faces, where separation is effected. Since it urges particles in directions parallel to the midplane, their responses are unaffected by their positions in the operating space.