Filter cartridge

Claim 1

A DEVICE FOR FILTERING AQUEOUS MEDIUM IN AQUARIUMS CONTAINING AQUATIC ANIMAL LIFE, COMPRISING IN COMBINATION: (A) A CIRCULAR BASE; (B) A POROUS PHYSICALLY SOLID FILTER MEDIUM HAVING AN AXIALLY DISPOSED RECESS WITH ONE END OPEN, POSITIONED ON THE BASE SUCH THAT THE LONGITUDINAL AXIS OF THE RECESS IS SUBSTANTIALLY NORMAL TO THE PLANE OF THE BASE; AND THE OPEN RECESS END IS FARTHER FROM THE BASE; (C) A HOLLOW CYLINDRICAL BODY EXTENDING FROM THE BASE AND SURROUNDING THE FILTER MEDIUM, INCLUDING: (1) AN INNER CYLINDRICAL WALL COACTING WITH THE BASE TO FORM A FLUID CHAMBER FOR RECEIVING THE FILTER MEDIUM, THE END OF THE FLUID CHAMBER FARTHEST FROM THE BASE BEING OPEN; (2) A CONCENTRICALLY DISPOSED OUTER CYLINDRICAL WALL COACTING WITH THE INNER CYLINDRICAL AND BALTO FORM A CHAMBER FOR HOLDING BALLAST, THE END OF THE CALLAST CHAMBER FARTHEST FROM THE BASE BEING OPEN; (D) A CIRCULAR COVER REMOVABLY MOUNTED ON THE HOLLOW BODY FOR SEALING THE OPEN ENDS OF THE FLUID AND BALLAST CHAMBERS AND THE RECESS IN THE FILTER MEDIUM POSITIONED ON THE BASE; (E) MEANS COACTING WITH THE BASE FOR ALLOWING FLUID TO FLOW INTO THE FLUID CHAMBER FOR CONTACT WITH THE FILTER MEDIUM, SAID MEANS INCLUDING AT LEAST ONE SLIT DISPOSED IN THE BASE, THE WIDTH OF THE SLIT BEING NARROW RELATIVE TO THE LENGTH OF THE SLIT SUCH THAT SMALLER SPECIES OF AQUATIC ANIMAL LIFE WILL NOT BE DRAWN INTO THE FLUID CHAMBER; (F) MEANS COACTING WITH THE FILTER MEDIUM FOR POSITIONING THE FILTER MEDIUM ON THE BASE AND IN THE FLUID CHAMBER;

Claim 2

A DEVICE FOR FILTERING AQUEOUS MEDIUM IN AQUARIUMS CONTAINING AQUATIC ANIMAL LIFE, COMPRISING IN COMBINATION: (A) A CIRCULAR BASE; (B) A POROUS PHYSICALLY SOLID FILTER MEDIUM HAVING AN AXIALLY DISPOSED RECESS WITH ONE END OPEN, POSITIONED ON THE BASE SUCH THAT THE LONGITUDINAL AXIS OF THE RECESS IS SUBSTANTIALLY NORMAL TO THE PLANE OF THE BASE; AND THE OPEN RECESS END IS FARTHER FROM THE BASE; (C) A HOLLOW CYLINDRICAL BODY EXTENDING FROM THE BASE AND SURROUNDING THE FILTER MEDIUM, INCLUDING: (1) AN INNER CYLINDRICAL WALL COACTING WITH THE BASE TO FORM A FLUID CHAMBER FOR RECEIVING THE FILTER MEDIUM, THE END OF THE FLUID CHAMBER FARTHEST FROM THE BASE BEING OPEN; (2) A CONCENTRICALLY DISPOSED OUTER CYLINDRICAL WALL COACTING WITH THE INNER CYLINDRICAL AND BALTO FORM A CHAMBER FOR HOLDING BALLAST, THE END OF THE CALLAST CHAMBER FARTHEST FROM THE BASE BEING OPEN; (D) A CIRCULAR COVER REMOVABLY MOUNTED ON THE HOLLOW BODY FOR SEALING THE OPEN ENDS OF THE FLUID AND BALLAST CHAMBERS AND THE RECESS IN THE FILTER MEDIUM POSITIONED ON THE BASE; (E) MEANS COACTING WITH THE BASE FOR ALLOWING FLUID TO FLOW INTO THE FLUID CHAMBER FOR CONTACT WITH THE FILTER MEDIUM, SAID MEANS INCLUDING AT LEAST ONE SLIT DISPOSED IN THE BASE, THE WIDTH OF THE SLIT BEING NARROW RELATIVE TO THE LENGTH OF THE SLIT SUCH THAT SMALLER SPECIES OF AQUATIC ANIMAL LIFE WILL NOT BE DRAWN INTO THE FLUID CHAMBER; (F) MEANS COACTING WITH THE FILTER MEDIUM FOR POSITIONING THE FILTER MEDIUM ON THE BASE AND IN THE FLUID CHAMBER;