Mesh Size report
The term ‘Mesh’ is used to describe the size of an abrasive particle. U.S. Mesh Size is defined as the number of openings in one square inch of a screen. Since the size of one square inch screen is constant, the higher the mesh number, the smaller the screen opening and the smaller the particle that will pass through.
However, mesh size is not a precise measurement of particle size. It also depends on the thickness of the wire or strand used to make the mesh. Most ISM flow control components do not contain filter screens finer than 500 mesh. The primary reason for this is that as the mesh number rises, the space between the wires or strands becomes smaller.
Sieves and screens are widely used in pharmaceutical manufacturing and quality control to determine the particle size of the raw materials. This post explains more details about mesh and micron size.
Mesh Size Guide
Figuring out the mesh number is simple. All you need to do is count the number of openings in one linear inch of screen. This count is the mesh number. For example, a 4-mesh screen means four little square openings across one inch of screen. As the number indicates, the mesh size increases, the size of the openings, and thus the particles size captured by the screen decreases. Higher mesh numbers equal smaller particle sizes.
Due to the problem of open porosity, screens can be made with different materials with different thicknesses of strands of wire. The thicker the strands, the smaller openings a particle can pass through. The standards of different countries are also different. There are three existing standards: American, British, and Japanese.
US Mesh Conversion Chart
Micron is the measure of length most frequently used to describe tiny particle sizes. The official symbol for the micron or micrometer is μm, sometimes simplified as um. The chart below shows the approximate size in inches and microns for various mesh sizes. These values are only approximated.
| US Mesh | Microns | Inches |
|---|---|---|
| 4 | 4,750 μm | 0.187 |
| 5 | 4,000 μm | 0.157 |
| 6 | 3,350 μm | 0.132 |
| 7 | 2,800 μm | 0.111 |
| 8 | 2,360 μm | 0.0937 |
| 10 | 2,000 μm | 0.0787 |
| 12 | 1,700 μm | 0.0661 |
| 14 | 1,400 μm | 0.0555 |
| 16 | 1,200 μm | 0.0473 |
| 18 | 1,000 μm | 0.0394 |
| 20 | 850 μm | 0.0337 |
| 24 | 690 μm | 0.027 |
| 30 | 560 μm | 0.022 |
| 36 | 485 μm | 0.019 |
| 40 | 425 μm | 0.016 |
| 46 | 355 μm | 0.014 |
| 54 | 305 μm | 0.012 |
| 60 | 250 μm | 0.01 |
| 70 | 210 μm | 0.0083 |
| 80 | 165 μm | 0.0065 |
| 90 | 145 μm | 0.0057 |
| 100 | 149 μm | 0.0059 |
| 120 | 125 μm | 0.0049 |
| 140 | 105 μm | 0.0041 |
| 150 | 89 μm | 0.0035 |
| 170 | 88 μm | 0.0031 |
| 180 | 76 μm | 0.003 |
| 200 | 75 μm | 0.0029 |
| 220 | 63 μm | 0.0025 |
| 240 | 53 μm | 0.002 |
| 280 | 44 μm | 0.0015 |
| 320 | 36 μm | 0.0012 |
| 400 | 23 μm | 0.00087 |
| 500 | 19 μm | 0.00075 |
| 600 | 16 μm | 0.00063 |
| 800 | 12 μm | 0.00047 |
| 1000 | 9 μm | 0.00028 |
| 1200 | 6 μm | 0.00024 |
Conclusion
Mesh is the most common measurement unit used for the sieves and screens. Generally, 40 and 400 mesh sieves are used in pharmaceutical manufacturing during the shifting and milling of raw materials. The fitness of any sieve or screen depends on the width of the wire. A thick wire can not make a fine sieve, and a thin wire can not make a thick sieve. Fine sieve above 400 mesh, the particle size described in microns.
