A Study on Modifying the Calculation Model of Valid Opening Size of Heat - bonded Nonwoven Fabrics

It has been found that there are marked errors in the value of valid opening size of heat - bonded nonwoven fabrics between theoretical calculations and engineering measurements. A new modified theoretical model is advanced in this paper. The equivalent diameter of the pore of a fibre web is used to calculate the valid opening size instead of the maximum diameter of inscribed circle used, because the fibres in practical fibre webs arc flexible elastomers with definite diameters and the pore of fibre web may produce deformation in screening test and engineering usage. The results show that the theoretical calculations coincide well with the engineering measurements. This method offers a theoretical basis for computer simulation to the performance of filters of heat -bonded nonwoven fabrics.