Originally Posted By: webfors
What's great is that the pleats can't fold over and tear with this design AND they know how to make tight even pleating. Amazing right?!I love it!
See above for your answer; ends are glued. Only way for oil to pass is through the center tube since there's a nice top and bottom seal with the well designed center tube which seals perfectly ...
Great design IMO.
I agree, mostly. It's probably less expensive to manufacture, besides. Very clever.
There's usually no center tube in the cartridge version, only one in the cap, and it doesn't seal directly to anything (or need to). Overall sealing against oil bypassing around the ends is more reliable than with typical rigid-end-cap cartridge designs, in my opinion.
I've seen cartridges of superficially similar design of another brand in which the sealing glue in the ends of the pleats seems to be missing. I'm not sure whether it's present but hidden, or they have a serious quality problem, or they've proven oil won't actually bypass through those gaps between pleats.