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Screen mesh size and aperture micron conversion

2011-4-10   Source:   Browse:4292

    Screen mesh size and aperture micron conversion - sieve for screening material component is the screen for sieving machine sieve mesh with micron said aperture size conversion is a headache, this detailed elaborate sieve mesh aperture with micron conversion.
Sieve diameter ( m) = 14832.4 / a sieve mesh
Unit of measure head size is that the raw material particle size, generally to particles of maximum length . " The mesh is expressed in standard sieve size. In the Taylor standard screen, the mesh is 2.54 cm (1 inches) in length in the mesh number and referred to as the eyes.
Taylor standard sieve : Taylor sieve indexing is to 200 mesh sieve size 0.074mm as a benchmark, multiplied or divided by a main module of root mean square (1.141 ) ^ n ( n = 1, 2, 3... ... ) 200, get a coarse or fine mesh size, if the number 2 of the root of four (1.1892 ) n power to multiply or divide by 0.074mm, you can get a series of indexing fine sieve size.
Mesh the greater the said particles are more carefully. Similar to the microstructure of the magnification.
Mesh before the sign said whether leaking through the mesh mesh. Negative energy leaking through the mesh mesh, i.e. a particle size smaller than a mesh size ; and the positive number can not leak through the mesh mesh, i.e. particle size is larger than the mesh size. For example, particles are - 100 ~ + 200 mesh, said that these particles can be from 100 to mesh leakage but can't from 200 to mesh leakage, in screening the mesh particles, should be the heads of several large (200 ) on the head of a small (100 ) of the screen below, in the heads of large (200 the screen left ) is 100 ~ 200 purpose particles.

   The number is the number of holes per square inch is hole number. Mesh the greater the aperture is small. In general, mesh x aperture ( micron number ) = 15000. For example, 400 objective to screen aperture of 38 microns ; 500 purpose screen aperture is approximately 30 microns. Due to the presence of open porosity, also it is because the mesh when the wire thickness is different, different national standard is not the same, the presence of American Standard, British standard and Japanese standard three, which the United Kingdom and the United States are similar, the Japanese are greatly different. China is the use of the American national standard, also available formula given above is calculated. The Taylor standard sieve sieve size comparison table. Below webpage to see detailed information.
This definition can be seen that the mesh size determines the screen aperture size. While the screen aperture determines the size of the sieving powder maximum particle Dmax. Therefore, we can see that 400 the purpose of polishing powder completely has the possibility is very small, such as only 12 microns, is also entirely possible is 10 microns to 20 microns. Because the screen aperture is approximately 38 microns. We produce 400 the purpose of polishing powder D50 is 20 microns. The attached figure is this kind of polishing powder photographs, pay attention to scale is 50 microns.
Therefore, with the mesh to constant polishing powder particle size is inappropriate, the correct approach should be used in particle diameter (D10, median diameter of D50, D90) to represent the particle size, with mesh conversion maximum particle size. If you read the Japanese on the abrasive the standard of JIS, will feel very scientific. Each of their number of abrasive are given to D3, D50, D97 requirements, but with a different principle of particle size analyzer when the data are different. Among the requirements are very strict. For example, D50 is 2 micron powder, D3 is approximately 0.9 microns, D97 is 4 microns. What do you mean? Which is the 2 micron powder, of less than 0.9 microns and not more than 3%, more than 4 microns and not more than 3%. This is very strict, found on the market in the vast majority of polishing powder (including foreign) cannot meet this requirement, especially fine powder standard.
The mesh size characterization of polishing powder particle size are there for a reason. Old polished flour mill adopts dry grinding and dry sieving technology, so there will be 300 purpose powder D50 is approximately 9 microns, 500 to D50 is 2 microns. All this down, also can guide production and use. But with the new production process has more high precision polishing needs, this method should be improved.
Abrasive industry on the screen mesh size and the pore size of the national standards, we can refer to.
Interpretation of (two )
1 eye refers to every square inch screen empty eye number, 50 head means per square inch on the hole is 50, 500 is 500, two more high, hole number. In addition to said screen holes, at the same time it used to express through the mesh of the particle size, the higher the number, the smaller the particle size.
2 powder particle size known particle size. The particle shape is very complicated, there are usually the granularity, the sedimentation size, equivalent volume size, equivalent surface area of particle size of said method. The granularity is particles can be obtained by screen mesh size, with a 1 inch ( 25.4mm) the width of the screen mesh numbers, so it is called a" mesh ". Currently at home and abroad has not been uniform particle size of technical standards, every enterprise has its own size index definition and representation method. In different countries, different industries have different screen sizes standard, so the "eye " meaning it is difficult reunification.
At present on international comparison of Enteromorpha equivalent volume particle diameter to calculation of particle size. With m or mm.