Abstract: This disclosure concerns a vessel or housing having a removable domed cover and a horizontal partition in the housing to form separate dirty and clean liquid chambers, and having a single large vertical cylindrical pleated filter cartridge clamped against the lower side of the partition in the dirty liquid chamber in the housing. The filter cartridge has a central perforated tube which axially fits over and is spaced from a vertical outlet duct extending up from the bottom of the housing through an aperture in the partition, which aperture forms an annular opening from the interior of the filter cartridge into the clean liquid chamber in the domed cover. The lower end of the filter cartridge seals to a sleeve around the bottom of the vertical outlet duct. The seals for the top and bottom of the cartridge may comprise integral soft plastisol annuli or ring gaskets in the harder plastisol end discs which seal the ends of the pleats of the filter cartridge and the ends of its central perforated tube.

Abstract: The disclosure concerns a hollow cylindrical filter cartridge composed of an annular pleated filter medium surrounding a central perforated plastic tube, the ends of which cartridge and tube are embedded into plastic annular discs for closing the ends of the pleats of the filter media and providing an internal centrally threaded socket adjacent the inside of said perforated tube, which socket has an inner integrally projecting shoulder. Continuous outwardly threaded plastic nipples having a length of slightly more than twice the depth of said sockets to their shoulders provide connections between adjacent axially aligned cartridges which are sealed together by the abutment of the ends of said nipples against said shoulders. A plastic internally threaded cap having a depth greater than half the length of said nipples, may be threaded on the outer end of a nipple extending from a cartridge for closing that end.