This nonwoven is made by puncturing loosely arranged fleece with numerous needles. Thus the fibers are entwined and the fleece gets mechanically bonded until it can be used as filter fleece. A very fine fiber structure and therefore increased pore volume is the reason for a many times larger filter surface. The special bonding type of the single fibers in needle felts
can be compared with a drainage system. As a result, a high separation efficiency of the dirt particles can be achieved right from the start of the filtration. The possibility of depth filtration of ultra-fine particles make these nonwovens especially suited for the use with grinding machines.