A pleated cartridge is cleaned by a short pulse of compressed air fired down the inside of the element. The air has to travel the full length of the pleat pack to release the dust that has collected on the outside — and that is exactly where a plain cartridge struggles.
The problem with an open top
Without a venturi, the pulse expands and loses energy in the first third of the cartridge. The top of the element cleans well, the bottom stays loaded, and differential pressure creeps up until the whole set is replaced. You can see the pattern on a used cartridge: a clean band at the top and a dark band at the bottom.
What the four-lug end cap changes
KNT-SE moulds the venturi into the ABS end cap itself. The four lugs locate the element in the tube sheet and the internal profile accelerates the pulse air down the core, so each jet reaches the far end of the pleat pack with enough energy to release the dust there too.
The practical result is a cartridge that cleans evenly along its whole length: lower average differential pressure, a longer interval between replacements, and less media lost to work-hardening from repeated ineffective cleaning.
Supporting details
- Stainless steel support bands hold the pleat spacing so the pulse cannot deform the media; band count rises with cartridge length.
- A square-hole inner core keeps resistance low across the element, which matters when the fan is already selected.
- An EVA sealing ring with a clip fit stops unfiltered air bypassing the pleat pack at the tube sheet.
Six models cover 200 mm and 250 mm outer diameters in 660, 800 and 1000 mm lengths, with a filter area from 3.5 to 7.6 m². The selection table on the KNT-SE page lists air volume at both 0.8 m/min and 1.5 m/min face velocity so you can match the element to the collector rather than guessing.
