Patent ID: 6032807
Filing Date: 2000-03-07
Classification: A61M,B01D,Y10S

Abstract:
A method for correlating average fiber diameter with performance for a filtration media comprising a matrix of a first component fiber having a first diameter and a second component fiber having a second diameter less than the first diameter, the method comprising the steps of(1) manufacturing the filter media with a selected matrix of the first component fiber and the second component fiber,(2) physically measuring the density and diameter of the first component fiber;(3) deriving the diameter of the second component fiber without physical measurement using the following equation: ##EQU7## where: d is the diameter of the second component fiber (in cm, or, by multiplying cm by 10,000 in microns);.rho. is the density of the second component fiber (in g/cm.sup.3); andA/W is the area-to-weight ratio of the second component fiber (in cm.sup.2 /g);(4) deriving the length (in cm) of each first and second component fiber present in 1 gram of the matrix, using the following equation: ##EQU8## where: .sub.i is the selected fiber whose length is being derived;L.sub.i is the length of the selected fiber (in cm) present in 1 gram of the matrix;Q.sub.i is the weight fraction of the selected fiber (in g) (expressed as a decimal; e.g., 10%=0.1 g);.pi. is 3.1417;d.sub.i is the diameter of the selected fiber (in cm); and.rho..sub.i is the density of the selected fiber (in g/cm.sup.3);(5) deriving the number average diameter (in cm) of all first and second component fibers present in the matrix by adding together, for each first and second component fiber, the product of the length L.sub.i (in cm) and diameter (in cm) divided by the length L.sub.i (in cm), using the following equation: ##EQU9## (6) observing a selected performance characteristic of the filtration matrix,(7) repeating steps (1) to (6) with different matrixes of the first and second component fibers, each matrix selected to create a different number average diameter of first and second component fibers, and(8) expressing change in the selected performance characteristic as a function of change in number average diameter of the first and second component fibers present in the filtration media matrixes.