Proud China environmental protection of the steel ring needled felt filter bag on the category of filtration efficiency and service life reaches a new field, using the advanced technology design, make the service life of filter bag have greatly extended, avoid of fibers on the surface of the needled felt filter bag surface, through special singeing polishing processing, reduce the surface of the fiber, but still keep the permeability of the steel ring sewn filter bag with pure fiber needled felt, using the method of acupuncture stereoscopic 3 d filter layer, caused by adopting the principle of depth filtration, liquid flow back to tortuous paths, the particles to intercept the stranded on the inner wall of the filter bag surface and deep, with solid or colloidal particles with high capture. Uniform material thickness, stable pore size and enhanced mechanical strength, making the filter bag more efficient, longer online time and other characteristics.