Sieve theory and the development of screening machine

Made up of different particle size of the coal industry to written records, the level 15 commercial coal, extensive coal particle size on coal classification under the first-run. After the coal to the surface, fell to the solid ground so that it reaches a certain level of granularity at the same time, some fixed sieve sieve but bar screen, which is to continue to the present fragile materiel sieve size 89 referred to coal screening. But size grading, was to by 19 was in the mine face, cast steel sieve plate, left. So, fixed screen is made up of by a number of rods, roller screen. To detach, has a long history. From the United Kingdom is, due to the needs of the market, in order to provide a variety of grains discipline prevailed in the second half.