Particle Size - US Sieve Series and Tyler Mesh Size Equivalents

Background

Sieving or screening is a method of separating a mixture or grains or particles into 2 or more size fractions, the over sized materials are trapped above the screen, while undersized materials can pass through the screen.

Sieves can be used in stacks, to divide samples up into various size fractions and hence determine particle size distributions.

Sieves and screen are usually used for larger particle sized materials i.e., greater than approximately 50µm (0.050mm).

Size Equivalents

Two scales that are used to classify particle sizes are the US Sieve Series and Tyler Equivalent, sometimes called Tyler Mesh Size or Tyler Standard Sieve Series. The most common mesh opening sizes for these scales are given in the table below and provide an indication of particle sizes.

US Sieve
Size

Tyler Equivalent

Opening

mm

in

-

Mesh

8.00

0.312

-

3 Mesh

6.73

0.265

No. 3½

3½ Mesh

5.66

0.233

No. 4

4 Mesh

4.76

0.187

No. 5

5 Mesh

4.00

0.157

No. 6

6 Mesh

3.36

0.132

No. 7

7 Mesh

2.83

0.111

No. 8

8 Mesh

2.38

0.0937

No.10

9 Mesh

2.00

0.0787

No. 12

10 Mesh

1.68

0.0661

No. 14

12 Mesh

1.41

0.0555

No. 16

14 Mesh

1.19

0.0469

No. 18

16 Mesh

1.00

0.0394

No. 20

20 Mesh

0.841

0.0331

No. 25

24 Mesh

0.707

0.0278

No. 30

28 Mesh

0.595

0.0234

No. 35

32 Mesh

0.500

0.0197

No. 40

35 Mesh

0.420

0.0165

No. 45

42 Mesh

0.354

0.0139

No. 50

48 Mesh

0.297

0.0117

No. 60

60 Mesh

0.250

0.0098

No. 70

65 Mesh

0.210

0.0083

No. 80

80 Mesh

0.177

0.0070

No.100

100 Mesh

0.149

0.0059

No. 120

115 Mesh

0.125

0.0049

No. 140

150 Mesh

0.105

0.0041

No. 170

170 Mesh

0.088

0.0035

No. 200

200 Mesh

0.074

0.0029

No. 230

250 Mesh

0.063

0.0025

No. 270

270 Mesh

0.053

0.0021

No. 325

325 Mesh

0.044

0.0017

No. 400

400 Mesh

0.037

0.0015

The mesh number system is a measure of how many openings there are per linear inch in a screen. Sizes vary by a factor of √2. This can easily be determined as screens are made from wires of standard diameters, however, opening sizes can vary slightly due to wear and distortion.

US sieve sizes differ from Tyler Screen sizes in that thay are arbitrary numbers.

 

Primary author: AZoM.com

 

Date Added: May 15, 2002 | Updated: Jun 11, 2013
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