Patent ID: 7708148

Claim:
A filter cartridge comprising: an elastic cartridge housing; a filter element located within the elastic cartridge housing; a rigid cartridge head permanently attached to one end of the elastic cartridge housing and comprising a connection member configured to prevent the filter cartridge from disengaging from a filter manifold; and an open volume within the filter cartridge to be filled with water at line pressure; the elastic cartridge housing comprising a first material that will begin to deform as the water freezes, and will deform and expand radially outwardly, but not rupture, during a freezing event of the water filling said open volume, the integrity of the first material being maintained after the freezing event, said elastic cartridge housing not enclosed by any other member; the rigid cartridge head comprising a second material that will maintain its physical shape at line pressure and during the freezing event; wherein the rigid cartridge head remains affixed to the elastic cartridge housing after the freezing event.