Viscous Filters are pre filters that are permanent recleanable metal panel elements which are designed for general ventilation and air conditioning system applications as well as for electric motors and plenum air for working areas and is specially designed to handle very high volume of air with heavy dust load, it is most suitable for areas where surrounding air contains high dust concentration such as coal and dust mines, steel plants, foundries and cement plant. These filters are combination of flat and corrugated layers of metallic meshes of varying mesh sizes and wire diameters is used as filter media. These can be reconditioned by washing so are an economical and used as pre filter for fine and hepa.