Bag filters can be divided into single bag filter, various types of multi-bag filter, double bag filter, etc., and wherein the multi-bag filter is the relatively rapid development in recent years one, along with the its development, and its applications are not broken in the expansion has now been widely used in petroleum, chemical, mining and the like. Of course, the rapid development of multi-bag filter is inseparable from its own merits. Since the multi-bag filter is a filter in a horizontal plane in the form of an addition, during operation of the device in the slurry due to the large particle settling velocity is greater than the fine particles, so it will soon sink to the filter layer formed on a surface high water permeability initial filter layer. Due to the small filter layer resistance at the beginning of the fine particles it has played a certain role in trapping, so that the cake layer structure is reasonable, but also reduces the filter cloth blockage caused by fine particles, thus filtration resistance, high filtration efficiency, filtrate clarification high. The thickness of the filter cake disposed horizontally formed on the surface more uniform, and the filter cake in the washing liquid is also distributed evenly, thereby increasing the efficiency of displacement washing of the filter cake, since the filter surface is a relatively narrow strip, it is convenient realization washed downstream or multi-stage counter-current, thus improving the efficiency of the filter cake was washed and get as high wash concentration. Multi-bag filter filtering surface elongated shape, you can easily adjust the filter area, the length of the washing zone, dry area of distribution, to optimize operation of the process, and the filtrate and washings recovery requirements can be strictly separated, you can also press cake moisture content requirements to shorten or lengthen the length of the dry zone. Multi-bag filter can also be designed according to the deformation of materials handling and process requirements, to meet different requirements. In short, the many advantages of multi-bag filter is essential to promote its rapid development.