Mesh Count Wire Diameter and Open Area Explained

Mesh Count Is Not an Opening Size

Mesh count is the number of openings per linear inch. A 100 mesh cloth has one hundred openings across one inch, counted from the centre of one wire to a point one inch away.

Because the wire itself takes up space, two cloths with the same mesh count can have different openings. Wodong lists 100X100 mesh at three wire diameters, 0.0045 inch, 0.004 inch and 0.0035 inch, and the aperture moves from 0.14mm to 0.17mm across them.

Wire Diameter Buys Service Life

A thicker wire in the same mesh count gives a smaller opening and a stronger cloth. That is the trade the specifier is actually making.

The same rule applies to sheet media. A thicker perforated sheet lasts longer in the same duty.

Open Area Governs Flow

Open area is the percentage of the cloth that is hole rather than wire. At 1x1 mesh the figure is 84.6 percent. At 635X635 mesh it is 25 percent.

Low open area means a higher pressure drop for the same flow, which is why fine screens are usually supported on perforated metal rather than used on their own.

Where the Numbers Stop

Wodong weaves from 1 mesh to 635 mesh in 304, 316 and 316L, in rolls 30m long or customized and 3 foot to 2 meters wide.

Dutch weaves take the rating further. A 400x2800 twill dutch weave carries a nominal rating of 1 micron and an absolute rating of 6 to 7 micron.