FILTERING MATERIAL AND METHOD FOR ITS PRODUCTION Russian patent published in 1994 - IPC

FIELD: purification of air and gases. SUBSTANCE: polymer solution is affected by centrifugal spraying, the process is carried out in electrostatic field through two fiber-forming devices having expenses 40-50 cm³/min and 25-35 cm³/min respectively. Elongation time in the second device is by 15-20% more than in the first one. Thus prepared material has superthin polymer fibers, their content in the first and in the second layer is 55-70% and 30-45% respectively. Average diameter of fiber from the first and the second layer is 4-9 μm and 1-3 μm respectively. EFFECT: improves quality of desired product. 2 tbl