A pleated filter cartridge for filtering liquids including an annular filter
element
having a filter material which is a thin non-perforated non-woven material of flash-spun
plexifilamentary high-density polyethylene fibrils, the filter material having
a pressure drop of less than 4 psid at a flow rate of 10 gal/hr and a filtration
efficiency of at least 98% of 1-2 micron particulates at a pressure differential
of 30 psid. The filter material preferably has a mean flow pore size greater than
4 microns while its normal pore-size filtration rating is 1 micron, and preferably
has a thickness of less than about 0.15 mm, most preferably less than or equal
to about 0.13 mm. The filter element preferably has two layers, including a mesh
layer, preferably of a low-density polyethylene. The mesh most preferably has a
softening temperature range below the lower end of the softening temperature range
of the high-density polyethylene filter material, and is tack-point interconnected
to the filter material without having compromised the filter material.
