Abstract: A PSA, especially VSA, plant for separating a gas stream, operating in a production cycle and comprising at least one adsorber, preferably two or three adsorbers, and several valves having long and heterogeneous operating times. More specifically, the average operating time (&mgr;) of the valves is such that: 0.5 s<&mgr;<2 s and the operating time (&Dgr;t) of each of the valves is such that: &mgr;−x<&Dgr;t<&mgr;+x, with 0.1 s<x<0.5 s. The invention also relates to the use of such a PSA plant for producing a gas stream rich in oxygen, in nitrogen or in hydrogen, particularly a stream comprising more than 80% oxygen, which is then sent to an oxygen-consuming plant chosen from a combustion furnace, a paper-pulp manufacturing unit and a water treatment unit.