Abstract: The invention relates to a fitting for distributing a gas flow to two or more flow ducts, wherein the fitting has an inlet connecting piece (20) and two or more separate outlet connecting pieces (21, 22), wherein upstream of each outlet connecting piece (21, 22) there is arranged a disc valve, wherein the disc valve inserts (15, 16) of two or more disc valves are kinematically coupled, and to a method for cleaning filter elements (4) immersed in a basin (1), in particular diaphragm filters, by aeration of the filter elements by means of gas bubbles which are introduced into the basin (1) below the filter elements (4) via aerators (5), wherein a gas flow for aerating the filter elements (4) is generated by means of a blower (7), wherein the gas flow is distributed by means of a fitting to two or more aerators (5), wherein the distribution of the gas flow takes place discontinuously, such that a pulsed aeration of the filter elements (4) of varying duration takes place at irregular intervals.