PURPOSE: To improve the performance of a nonwoven filter by a method wherein electret films to which small holes are drilled are laminated between fiber webs changed into electrets or not changed into electrets, and one portion of fibers is penetrated and entangled to the films.
CONSTITUTION: This electret filter is manufactured in such a manner that electret films 1 with a large number of small holes drilled by means of needle punching are laminated between fiber webs 2, 3 changed into electrets or not changed into electrets, one portion of web fibers is penetrated and entangled to the films 1 by means of needle punching and the whole is unified. Thus, this filter has sufficient structural strength while being excellent in capacity, which separates minute grains floating in a fluid from the fluid, and the durability of dust collecting capacity though it has the structure of a nonwoven filter, and pressure loss in case of operation is also little.
SHINAGAWA TAKEHISA
WATANABE TAKUJI
TAKAHIRA TAKASHI
NITTA BELT KK
| JP46011654A |