On Oct 24, 4:27*am, Smitty Two wrote:
In article ,
*"Bob F" wrote:



Why else would they pleat filters?

To make them intrinsically stronger, and functionally stronger by
placing filter material at an angle to the force of the moving air.

They make them pleated so there is MORE surface area. That allows a
denser filter which traps smaller particles while still maintaining an
acceptable pressure drop. As another benefit, it allows the filter
to collect more dirt while still maintaining a reasonable pressure
drop.

I don;t see how anyone could not recognize that more filter area
translates into less resistance and less pressure drop. Imagine
breathing through a length of 2" plastic pipe with a sheet of dense
filter material fastened straight across in the middle. The filter
is dense enough to make it difficult to draw air. Now imaging a
filter of the same material, shaped like a cone and instead of being
just a 2" circle, it;s an extended cone, like an exagerated coffee
filter, stretching 3 inches within the pipe. Which would you rather
breathe through?