Filter media tensioning device

Claim 1

In an improved filtration apparatus including an upper tank for holding dirty liquid and having an imperforate end wall and a perforate floor, and a lower filtrate compartment beneath the floor for receiving liquid from the upper tank through said perforate floor, filter media between said upper tank and said perforate floor, a guide roller over which the filter media is moved downwardly and positioned to guide the filter media along the end wall and along the floor for filtering out contaminants as the dirty liquid is received from the tank into the filtrate compartment, and means for moving the filter media, wherein the improvement comprises: a filter media feed mechanism having an axis of rotation and mounting a roll of filter media adjacent said guide roller, said feed mechanism being mounted relative to the upper tank; a rotatable tension roller and means to position said tension roller for providing a constant tension, the tension roller movably mounted for generally vertical movement in a range of motion between said feed mechanism and the guide roller thereby to provide constant tension on the filter media being moved; and a brake mechanism means cooperably connected to said filter media feed mechanism and rotatable tension roller for stopping and releasing filter media; said brake mechanism means being actuable by the rotatable tension roller to release filter media as said tension roller moves upwardly to an upper limit of its range of motion and said brake mechanism being applied as said tension roller moves downwardly to a lower limit of its range of motion.