Patent ID: 7334579
Filing Date: 2008-02-26
Classification: A62B

Abstract:
1. A method for making a low resistance-to-flow fluid filtration filter comprising the steps of: i) providing a plurality of sheets of fluid filtration media, each of said sheets having an upper surface and a lower surface and comprising a center point, a central zone, a shaped perimeter and an intermediate zone, said center point being located within said central zone and said central zone being located within said intermediate zone, said shaped perimeter of each of said sheets defining the outer edge of its respective sheet of filtration media; each of said sheets further comprising a folding zone, said folding zone surrounding said central zone and being surrounded by said intermediate zone, ii) forming, in each of said sheets, a plurality of primary folds within said folding zone, each of said primary folds being formed around an axis the projection of which lies within said folding zone and forms a fold line which is spaced apart from said center point, said plurality of primary folds, so formed a) creates a plurality of fold lines which, as connecting segments beginning and ending at the same point, define a seamless pad-type filter outer perimeter and b) forms a plurality of positive and negative secondary creases, said secondary creases being formed around a plurality of positive and negative crease lines, respectively, said crease lines being inclined to said fold lines, said plurality of fold lines forming pluralities of positive and negative crease lines, said crease lines shaping said shaped perimeter of each of said sheets of filtration media into pleats, said pleats forming a primary flow aperture in each of said sheets formed in accordance with this step, iii) sealing, in each of said sheets, said pleats so formed in accordance with step ii, such that a fluid passing through a primary flow aperture passes only through at least one of the central zone, the intermediate zone and the folding zone of said sheets, thereby creating a plurality of seamless pad-type filters, iv) setting aside one of said seamless pad-type filters as a final assembly filter, v) except for said final assembly filter, providing a pad-to-pad communication aperture in each of said seamless pad-type filters so formed in accordance with step ii, said communication aperture being located within said central zone, and vi) assembling said plurality of seamless pad-type filters by forming impermeable connection zone(s), said connection zones joining the communication aperture of a filter to the primary flow aperture of its immediately adjacent filter and such that said final assembly filter being the terminating end of assembled said plurality of seamless pad-type filters.