sieves

Sieves are a very ancient tool, at least as old as the open weave baskets used to separate grain from refuse. A later more sophisticated sieve was the medieval miller's bolting cloth. Even more precise sieves began to be made during the Industrial Revolution. In 1800, for example, to extend the supply of grain during an agricultural crisis the king of England forbade the baking of bread with flour that would pass through a sieve with 13 wires on each side of a square inch. (41 George III c 16, 1800)

Many occupations are concerned with the size of large numbers of small objects, such as grain, seeds or soil particles. If a graded series of sieves is available, a batch can be shaken through a stack of sieves with increasingly smaller holes. Weighing the amount left behind in each sieve gives a series of masses which is a size distribution for the particles in the batch. In such situations it is more accurate to describe the sizes of the particles in sieve numbers, rather than as particle diameters. For an example of how sieve numbers are used to grade a commercial product, see abrasives.

The sieves used in industry and the laboratory are precision products. The smaller the particle that is not to pass through the sieve, the finer the wires of the sieve–but despite that, the smaller the proportion of the sieve's area which is hole.

Test sieve
apertures
ISO 
(See note 1.)
U.S. Alternate sieve designations,
a survival of an older system.
 Mesh sizes are roughly
the number of openings per inch.
Tyler Screen Scale
Equivalent
Designation
125 mm 5 inches  
106 mm (4.24 inches)  
100 mm 4 inches  
90 mm 3½ inches  
75 mm 3 inches  
63 mm 2½ inches  
53 mm 2.12 inches  
50 mm 2 inches  
45 mm 1¾ inches  
37.5 mm 1½ inches  
31.5 mm 1¼ inches  
26.5 mm 1.06 inches  
25.00 mm 1 inch
19.00 mm 3/4 inch 0.742″
16.00 mm 5/8 inch 0.624″
14.00 mm (0.53 inch)  
13.20 mm    
12.50 mm ½ inch
11.20 mm (7/16 inch)  
10.00 mm    
9.50 mm 3/8 inch 0.371"
9.00 mm    
8.00 mm 5/16 inch 2½ mesh
7.10 mm    
6.70 mm (0.265)  
6.30 mm ¼ inch
Fine Sieves
5.6 mm #3½ mesh 3½ mesh
5.00 mm    
4.75 mm #4 4
4.50 mm    
4.00 mm #5 5
3.55 mm    
3.35 mm #6 6
3.15 mm    
2.80 mm #7 7
2.50 mm    
2.36 mm #8 8
2.24 mm    
2.00 mm #10 9
1.80 mm    
1.70 mm #12 10
1.60 mm    
1.40 mm #14 12
1.25 mm    
1.18 mm #16 14
1.12 mm    
1.00 mm #18 16
900 µm    
850 µm #20 20
800 µm    
710 µm #25 24
630 µm    
600 µm #30 28
560 µm    
500 µm #35 32
450 µm    
425 µm #40 35
400 µm    
355 µm #45 42
315 µm    
300 µm #50 48
280 µm    
250 µm #60 60
224 µm    
212 µm #70 65
200 µm    
180 µm #80 80
160 µm    
150 µm #100 100
140 µm    
125 µm #120 115
112 µm    
106 µm #140 150
100 µm    
90 µm #170 170
80 µm    
75 µm #200 200
71 µm    
63 µm #230 250
56 µm    
53 µm #270 270
50 µm    
45 µm #325 325
40 µm    
38 µm #400 400
36 µm  
32 µm #450
28 µm  
25 µm #500 500
22 µm  
20 µm #635 625
15 µm   800
10 µm   1250
5 µm   2500

Notes:

(1) The ratio between adjacent sizes is the fourth root of 2, so the aperture size doubles every 5th size. Red lettering identifies sizes in common use in the United States that are ASTM supplementary values.

Standards

ASTM E-11.

ANSI Z23.1.

AASHO M92. 

Federal Spec. RR-S-366b.

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