919,470. Filters. BERLINE J. R. A. July 25, 1961 [July 27, 1960], No. 26925/61. Class 46. In a cluster of filtering tubes each tube 1 has a flared upper end supported by an annular rubber or plastic gasket 18 in a supporting plate 16 and is held under adjustable pressure from bolts 21 in washers 20 which, through tube retaining rings 19, exert pressure against a plurality of tubes simultaneously. Each tube consists of a core 2 of perforated sheet metal or expanded metal and a sheath 5 of metal or synethetic fabric e.g. " Terylene " Registered Trade Mark and is rigidly united with an endpiece 4 which is secured to a metal lattice 6 by a stud 8. For cleaning, filtrate accumulated in a dome of the filter housing is counterstreamed by the pressure of gas in the dome, or introduced thereto, and this with the help of the resultant vibration of the tubes, causes the filter cake on the outer face of the filter fabric to be removed. Alternatively, steam under pressure may be used to clean the tubes. The washers may be circular or star-shaped, each point of a star being assigned to a tube.