Mesh (scale)

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For other uses, see Mesh (disambiguation).

Mesh material is often used in determining the particle size distribution of a granular material. For example, a sample from a truckload of peanuts may be placed atop a mesh with 5 mm openings. When the mesh is shaken, small broken pieces and dust pass through the mesh while whole peanuts are retained on the mesh. A commercial peanut buyer might use a test like this to determine if a batch of peanuts has too many broken pieces. This type of test is common in some industries, and to facilitate uniform testing methods, several standardized mesh series have been established.

One well-known mesh series is the Tyler Equivalent. Tyler mesh size indicates exactly the number of openings per linear inch of mesh. For instance, a Tyler number 4 mesh will have 4 openings per linear inch, and 16 openings per square inch. This numbering system results in higher numbered meshes having smaller openings. The openings of adjacent mesh sizes in this series differ by a factor of \sqrt{2}.

To calculate the size of the openings in a mesh the thickness of the wires making up the mesh material must be taken into account. In practice, mesh openings are determined referring to a chart like the one below.

Powders and granular materials are sometimes described as having a certain mesh size (e.g. 30 mesh sand). By itself, this type of description is somewhat ambiguous. More precise specifications will indicate that a material will pass through some specific mesh, but will be retained by some specific tighter mesh. This type of description establishes a range of particle sizes.

[edit] Sieve size conversion chart

Sieve size (mm) BSS Tyler (approx) US (approx)
3.35 5 6 6
2.81 6 7 7
2.41 7 7 8
2.06 8 9 10
1.68 10 10 12
1.40 12 12 14
1.20 14 14 16
1.00 16 16 18
0.853 18 20 20
0.699 22 24 25
0.599 25 28 30
0.500 30 32 35
0.422 36 35 40
0.353 44 48 50
0.295 52 48 50
0.251 60 60 60
0.211 72 65 70
0.178 85 80 80
0.152 100 100 100
0.125 120 115 120
0.104 150 150 150
0.089 170 170 170
0.076 200 200 200
0.066 240 250 230
0.044 350 325 325
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