The present device is a detachable core for use with a cylindrical filter cartridge. The core includes a wire frame including at least two vertical struts oriented along a longitudinal direction. The wire frame includes an upper ring and a lower ring mounted to the distal ends of the vertical struts and further includes an upper flange and a lower flange mounted to the upper and lower rings respectively, wherein the lower flange is detachably mounted to the lower ring. Preferably the lower ring includes a gap in the lower ring to enable resilient compression of the ring by squeezing the lower ring in a radial inward direction prior to engagement with the lower flange. Preferably the cartridge filter includes elastomeric end caps and the cooperating rings and flanges are non-circular such that the elastomeric end caps conforms to the non-circular shape of the upper and lower flanges.