End connected filter cartridges

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. This cap has its rim clamped against the plastic disc directly opposite the end of the perforated tube for sealing that end of the cartridge. The opposite end of the cartridge or series of cartridges fromthe cap may have its outwardly extending nipple connected to a vacuum or suction source directly or through an adaptor, which connection also may be a support for that end of the cartridge or series of cartridges. One or more of these cartridges, usually two or three, may be placed in liquids in tanks, pressure vessels, irrigation ditches or ponds for filtering liquids, preferably water, including filtering water for swimming pools.