Self-sustaining pocket type filter

Claim 1

A pocket type fluid filter comprising: a pair of pocket forming sections, formed from sheets of material with said sections being integral along a common line to form the closed end of said pocket and having terminal supporting portions remote from said common line to form the mouth of said pocket, said pocket forming sections being folded to face each other and seamed along the longitudinal edges thereof to form the side edges of said pocket, each of said sections including inner and outer sheets of scrim material and expansible-compressible flexible filter medium sheet means therebetween, said sections further including longitudinally extending filter medium compression seams each seam lying wholly within a section and each being laterally spaced with respect to the others and extending substantially the entire distance from said closed end of said pocket toward said mouth to compress the filter medium therealong and to provide self-sustaining columns between said compression seams with said outer scrim sheet being of greater width between said compression seams than said filter medium sheet means and said inner scrim sheet to permit said filter medium columns to loft outwardly between said compression seams and give dimensional stability to said sections.