Abstract: A filtering device which is disclosed herein comprises a rising pipe bascially shaped into a cylinder having a drain port at its upper end and placed within a box-like basin to vertically extend, and a porous air injecting member contained within the rising pipe at its lower portion in a connected relationship to a pressurized air source to develop and upward flow of water within the rising pipe. In the filtering device, the rising pipe is formed of an elastic material to have a back wall comprised of a pair of mounting portions forming an angle slightly larger than that of the corner of the basin and connected to a connecting portion, and a front wall. The back and front walls are disposed respectively to be faced to the corner and to be faced inwardly of the basin when the filtering device is attached. The rising pipe has a cross-sectional configuration such that the back and front walls are connected to form a close section.

Abstract: A filtering device to be mounted in a water basin for aquarium fishes, comprises a vertically extending tubular filter case attached to the wall surface of the water basin and having a filtering chamber and closed upper and lower ends, a vertically extending filtering material accommodated in the interior of said filter case to divide the filtering chamber into an outer unpurified chamber and an inner purified chamber, a vertically extending suction pipe being fixedly secured to the filter case in the purified chamber and communicating with the lower end of the purified chamber, the filter case being perforated with a water intake port communicated to the unpurified chamber, and a pump unit being mounted on the filter case so as to circulate water in the suction pipe from the upper end of the suction pipe into the water basin.

Abstract: A filtering device includes a water suction case having a plurality of water suction ports connected to water flow passages formed therein so as to make gravel spreaded over the bottom of a water basin perform the filtering operation. The case is buried in the gravel, and a pumping means is connected to the water suction case so as to circulate water in the passage to the upper portion of the water basin.

Abstract: In a filter of the type in which at least part of a casing is buried with its suction ports in pebbles spread inside a water tank in order to let the pebbles exhibit a filter operation and suction means is connected to the casing, the improvement wherein the filter casing consists of a suction portion buried in the pebbles together with its suction ports, and a purification portion connected to the suction portion and having the upper part thereof closed by a detachable lid, a filter material dividing the purification portion into a purification chamber and a non-purification chamber and held by a frame member is removably fitted into the purification portion, and the suction means is supported by the lid in such a manner as to face the interior of the purification chamber.

Abstract: A filter comprising a filter case the interior of which is divided by a separator into upper and lower filtration chambers, a compact filter material of a cylindrical shape disposed in said upper filtration chamber so as to define on both outer and inner sides thereof a non-purification chamber communicating with upper suction ports formed at the upper part of said filter case and a purification chamber communicating with a drain pipe disposed on the upper surface of said filter case and having a large capacity, and a coarse filter material housed in said lower filtration chamber and serving also as a weight, said lower filtration chamber communicating with said purification chamber through passage ports formed in said separator while communicating with lower suction ports formed in a bottom surface of said filter case, said purification chamber communicating with an air feed port connected to an air pump.