Polyester dust filter bag is made of short fiber and twisting yarn with crisscorss and fine distributed nonwovens needle felt craft and post-processed by the hot rolling,singeing or coating,which make its surface more smooth,not easy to be obstructed by dust voidage.The Polyester needle felt applied widely and has good performance of permeability and chemical stablity.It is the ideal filter medium for the nomal temperature corrosive and acid-base gasses,oil and water seperation and filtration.