MULTILAYER ELECTROMAGNETIC SCREEN Russian patent published in 2010 - IPC H01Q17/00 

FIELD: physics.

SUBSTANCE: device relates to shielding from electromagnetic radiation and can be used for protecting manufacturing and residential premises from low frequency electromagnetic fields induced by electrical equipment. Flat screening layers (1, 2) placed outside the screen are made from sheet magnetically soft isotropic steel with relative initial permeability not less than 2×10³, and the bulk screening layer (3) placed in between is made in form of a rectangular steel grid whose cells are formed by guides 4 and short jumpers 5 which function as below-cutoff waveguides with respect to the fundamental harmonic of the frequency of the screened field. When screening industrial frequency fields, thickness of steel sheets from which the flat screening layers are made is not less than 1 mm, the diagonal of the window of the grid of the bulk layer is not greater than 300 mm, and the depth of the cells and thickness of the edges of the grid lie in the range of 80-300 mm and 40-160 mm respectively. Grid guides of the bulk layer are directed along and towards the dominant vector of the geomagnetic field. If there are weld joints 6 in flat layers 1 and 2 they should be parallel each other and perpendicular to the guides 4 of the grid of the bulk layer 3.

EFFECT: more efficient protection from effect of elliptically polarised magnetic field induced by three-phase electrical equipment.

10 cl, 1 dwg