Neva-Clog Screens

The Neva-Clog is a unique welded, high strength screen free of internal plugging. It consists of two sheets of light gauge metal in which circular perforations are made in predetermined hole diameter and spacing. The sheets are joined by spot welding in a specific pattern, dependent on the medium’s application. This welding pattern, besides assuring uniform joining of the sheets, controls the functional characteristics of the medium.

Although originally developed as an underdrain material, Neva-Clog has found wide use as the filter media on pressure and vacuum filter leaves. It is often used with round or rectangular leaves and flat or conical underdrains. It provides fast precoating, easy cake release and easy leaf cleaning due to a smooth surface. Neva-Clog resists abrasion and abuse during cleaning or acid washing. As the chamber material, Neva-Clog becomes a general purpose filter leaf for many applications when used with WEDGE-FLOW or Por-O-Septa.

Neva-Clog is used as a support for granular activated carbon in processing columns for removal of colors, odors, and tastes. It’s strength and performance characteristics have resulted in its installation in sugar, chemical, petrochemical, and food refining plants. Because of its rigidity, compared with woven media, it requires minimum undersupport and no protective top screen. Neva-Clog’s particle retentivity, in the range of 100 mesh, enables it to handle all corresponding granular carbon and bone char. It’s strength and freedom from internal plugging ensure long service life, making it especially valuable for towers in inaccessible locations or in hazardous service. Neva-Clog is also used for underdrains in catalyst towers, resin towers, and ion exchange units.


To receive cad drawings, quotes or additional product information please contact us.


  • Operating Principle

    Fluids pass through the holes of thetop sheet, turn at right angles to passthrough the controlled spacingbetween the sheets, then turn again atright angles to pass through the holesin the bottom sheet. Solids too large topass through are retained on thesurface. Finer particles are retained bythe formulation of a filter bed or cakeNeva-Clog operates best with freedraining solids or as a supportingmedium for precoat material.


    • Abrasion resistant
    • Abuse resistant
    • Easy cake release
    • Easy leaf cleaning
    • Fast precoating
    • High strength
    • Long service life
    • Rigid
    • Smooth surface


    Neva-Clog can be produced in any commercially available sheet metal possessing the proper perforation and welding characteristics.


    • Grade I is used for coarse retention
    • Grade II is used for finer retention
    • Grade III is used wherea flatter surface is desired, such as on filter leaves
    • The “back-to-back” isused where more restricted and moreequally distributed flow is desired

    Filter Leaf Designs

    • Rectangular
    • Bottom outlet, Bar Frame, Welded
    • Round
    • Bottom outlet, 966 Binder, Welded

    Filter Leaf Constructions

    • Neva-Clog Filter Media, Por-O-Septa® Chamber, 966 Binder
    • Neva-Clog Filter Media, Wedge Wire Chamber, Bar Frame wi:h Reverse “U”

    Underdrain Designs

    • Flat
    • Neva-Clog is ideal for permanent installation in flat tower bottoms. Discs may be rolled up for insertion through manways for easy installation.
    • Conical
    • Particularly suited to conical bottoms, Neva-Clog’s smooth surface facilitates discharge of solids.

    Underdrain Constructions

    • Neva-Clog Filter Media, Wedge Wire Support Screen, Multi-Grate Sub-support
    • Neva-Clog Filter Media, Por-O-Septa Support Screen, Multi-Grate Sub-support


    • Catalyst towers
    • Filter Leaves
    • Ion exchange units
    • Resin towers
    • Underdrains

    Industries Served

    • Beer
    • Chemical
    • High Fructose
    • Oil Additives
    • Petrochemical
    • Soda Ash
    • Sugar
    • Wastewater Treatment
    • Water Treatment
    • Wine
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