General application: Series F2 units for dry processing are designed for separating fine ferromagnetic particles present as 1% (weight) or less of the material to be processed.

Field intensity, field gradient and energy gradient: The F2 series is designed for high performance in separating fine ferromagnetic particles under difficult processing conditions. Two concentric solenoids with three water cooling coils – at the outer circumference of the larger solenoid, at the inner circumference of the larger solenoid, at the inner circumference of the smaller one and in between the two – provide the background field. The design provides major increase in field intensity without the problems attendant on hollow conductors carrying current in the water and the metal. Average background magnetizing field measured in the separating chamber with the pole pieces and matrix in place is 3,790 Gauss, more than twice the background field intensity of the F1 units.

The background field induces a field several times more intense in the grids which form the matrix. The dimensions and orientation of the vanes of the grids result in high field gradients at their collecting edges. Calculations employing advanced programs for evaluating magnetic fields indicate that the field induced in the steel is nearly 23,000 Gauss at the upper edges of the vanes and over 19,500 Gauss at their lower edges. Magnetic energy gradient (HdH/dx) in the regions immediately adjacent to these magnetized vane edges is about 243 x 10⁸ Gauss²/cm.

Matrices: The standard matrix is a stack of grids with inclined parallel vanes. The inclination of the vanes is reversed with each grid, to guide the material through the matrix in a zigzag course. As it pours over a vane edge and falls on the face of the vane below, the material is turned over and broken up again and again. Vane faces retard the flow and vane edges, where magnetic flux is concentrated, attract and hold the magnetized particles.

A choice of vane spacing and vane width is available. Special coating can be applied to surfaces of the matrix to aid the passage of difficult materials. For some applications grids wound of stainless steel ribbons – one crimped and one flat – can be used.

In the assembled matrix grids are spaced by stainless steel rings or cushioned by rubber strips at the outside rim. Special white rubber strips are supplied for processing pharmaceutical and food products.