Back-flushable filter cartridge assemblies

Abstract

Filter cartridge assemblies are provided with a generally cylindrical filter medium which defines a cylindrically shaped core space, and a pair of end caps. A threaded base member having detent projections receives at least one of the end caps, which itself is annular and has an interior cylindrical surface defining an interior space in alignment with the core space. The interior space is also provided with interrupted threads defining detent spaces. In use, therefore, the lower end cap may be threadably coupled with the threaded base member such that the detent projections are seated in respective ones of the detent, thereby minimizing the unintended threaded uncoupling therebetween. In another aspect, the filter cartridge is most preferably “coreless” and is capable of being sleeved over a permanent, reusable perforated core element. However, the core element is removably insertable within a base member to which the filter cartridge may be coupled. Specifically, one end of the core element is provided with an annular set ring. The set ring is rigidly connected to the exterior surface in surrounding relationship to the core element at a location spaced axially from the one of its ends (e.g., the lower end) towards the other end (e.g., the upper end). In use, the annular set ring provides a seat which bears against the base when the end of the core element is forcibly inserted thereinto.