Reverse flow aquarium filter device

Claim 1

A filter structure for aquariums comprising a casing constructed for mounting on a side wall of an aquarium tank, a unitary filter cartridge disposed in said casing with the bottom of the cartridge spaced upwardly from the bottom of the casing, forming a chamber therebelow, said casing forming a water inlet chamber adjacent said cartridge, communicating with said firstmentioned chamber, said cartridge having a bottom inlet wall provided with openings communicating with said first-mentioned chamber, and a top outlet wall which is provided with openings therein for the passage of water therethrough, said filter cartridge containing filter material in the form of discrete particles, interposed between said inlet and outlet walls of the cartridge, a peripheral wall of said cartridge having a portion thereof, disposed above said top outlet wall adapted to form a water discharge opening, over the lower edge of which water flowing through the top wall thereof may be discharged, said casing having a water inlet communicating with said water inlet chamber, through which water from the aquarium tank is adapted to be supplied and a water outlet adapted to be aligned with the discharge opening of said filter cartridge, means forming a weir disposed above said discharge edge and extending between said water inlet chamber and said discharge opening of said cartridge over which water may flow from the inlet chamber to said discharge opening and said casing outlet in the presence of an abnormal rise in water level in said water inlet chamber, whereby filtered water, or water passing over said weir may be returned to the aquarium tank.