Abstract: The process for introducing a filling gas into an enclosure initially containing a holding gas includes a step of introducing the filling gas into the enclosure as well as a step of extracting a specific gas initially contained in the filling gas or the holding gas from a mixture collected at the outlet of the enclosure, and possibly a step of recycling this extracted specific gas. Before the step of introducing the filling gas, the enclosure is purged using a purging gas which differs from the fill and holding gases.

Abstract: Process for separating a gaseous mixture by adsorption includes the steps of: (a) a cocurrent isobaric production (f.sub.p1 -f.sub.p2); (b) a pressure equalization between the adsorber undergoing decompression and another adsorber undergoing countercurrent recompression (f.sub.c1 -N.sub.4); (c) a cocurrent partial emptying to a reservoir (f); (d) a final countercurrent decompression (f.sub.a); (e) a countercurrent scavenging by the gas of the reservoir (f.sub.b); (f) a countercurrent partial recompression by at least one pressure equalization (f'.sub.e); (g) a countercurrent final recompression (f'.sub.di -F'.sub.