Johnson Wire Support Grid

A Johnson wire support grid – also known as a wedge wire support grid – is a structural component used inside filter vessels, ion exchange columns, and reactors. The grid is manufactured from V-shaped stainless steel profile wires resistance-welded to a grid of support beams. The grid supports filter media, resin beds, or catalyst particles while allowing fluid to pass through uniformly. For large-diameter vessels, the grid is manufactured in multiple segments that are assembled on site. It support grid is a well-established product in the water treatment and chemical processing industries.

The V-shaped slot geometry ensures effective media retention. The slots are narrow at the top surface and wider below, preventing media particles from becoming wedged. Slot openings range from 0.1 mm to 3.0 mm, with common applications using 0.2 mm to 0.5 mm. The slot opening must be smaller than the minimum media particle size. Slot tolerance is held to ±0.03 mm to ±0.05 mm. The open area typically ranges from 15% to 40%.

The support grid is constructed with V-shaped profile wires on the top surface and a grid of support beams underneath. For heavy-duty applications, support beams are spaced more closely and larger profile wires are used. Profile wire sizes commonly used include 1.5×3 mm, 2×4 mm, and 3×5 mm. The grid is manufactured with locating pins and bolted connections for segment assembly. Materials include stainless steel 304 and 316L, with 2205 duplex, Hastelloy, and titanium available for corrosive applications.