What does mesh size mean? Figuring out mesh sizes is simple. All you do is count the number of openings in one inch of screen (in the United States, anyway.) The number of openings is the mesh size. So a 4-mesh screen means there are four little squares across one linear inch of screen. A 100-mesh screen has 100 openings, and so on. As the number describing the mesh size increases, the size of the particles decreases. Higher numbers equal finer material. Mesh size is not a precise measurement of particle size.
What do the minus (-) and plus (+) plus signs mean when describing mesh sizes? Here’s a simple example of how they work. –200-mesh would mean that all particles smaller than 200-mesh would pass through. +200 mesh means that all the particles 200-mesh or larger are retained.
How fine do screens get? That depends on the wire thickness. If you think about it, the finer the weave, the closer the wires get together, eventually leaving no space between them at all. For this reason, beyond 325-mesh particle size is usually described in “microns.”
What is a micron? A micron is another measurement of particle size. A micron is one-millionth of a meter or one twenty-five thousandth of an inch.
Sieve Mesh # Inches Microns Typical Material 14 .0555 1400 - 28 .028 700 Beach Sand 60 .0098 250 Fine Sand 100 .0059 150 - 200 .0029 74 Portland Cement 325 .0017 44 Silt 400 .0015 37 Plant Pollen (1200) .0005 12 Red Blood Cell (2400) .0002 6 - (4800) .0001 2 Cigarette SmokeThe mesh numbers in parentheses are too small to exist as actual screen sizes; they are estimates included for reference.
Information found on the http://showmegold.org/news/Mesh.htm Show Me Gold Prospectors organization website.
1.[Mesh] is defined as the number of openings in one linear inch width of a screen. For example, a 50 mesh screen will have 50 openings in linear width per inch. The higher the mesh number, the smaller the screen openings. it is also used to indicate the particle size of the particles that can pass through the screen. The higher the mesh number, the smaller the particle size.
2.The size of the powder particles is called the particle size. The unit is expressed in μm or mm.
3.Due to different kinds of screens, the grid line diameters are different, the particle size corresponding to the same mesh is slightly different, and the standards established by countries and industries are also different. Currently, there is no uniform technical standards of the powder particle size in the world. so the meaning of “mesh” is also difficult to unify.
5.Commonly used particle size representation:
(1) The D value of the particle size distribution is marked as follows:
For example, the indication values are (D3, D50, D97). If a sample has D3 = 1 μm, it means that 3% of the mass particles are composed of particles smaller than 1 μm. D50 is also called the median diameter. If a sample has D50=5μm, it means that among the particles of all particle sizes constituting the sample, the mass of particles larger than 5μm accounts for 50%, and the mass of particles smaller than 5 μm also accounts for 50%. If a sample has D97 = 9 μm, it means that 97% of the mass particles are composed of particles smaller than 9 μm.
(2) Mesh size of product in noted with minus (-) and plus (+) sign as follows :
Mesh size with minus (-) sign indicate the particles can all pass through the mesh size. Mesh size with plus (+) sign indicate the particles can’t all pass through the mesh size. For example, a product identified as -100~200 mesh would contain particles that passed through a 100 mesh screen and can’t passed through a 200 mesh screen.
(3) The sieve residue ratio indication method:
The sieve residue refers to the manner in which the fineness of the powdery material is marked, and the mass ratio (%) of the powdery material remaining portion on the sieve after being sieved on the standard sieve. For example, if a powder is sieved with a 200-mesh sieve, the mass ratio under the sieve is 80%, and the mass ratio on the sieve surface is 20%, then we call the 20% powder as the sieve residue.