VPSA (vacuum pressure swing adsorption) is separating oxygen from air by vacuum decompression for desorption.

The pressure swing adsorption oxygen generation uses air as the feed gas which is forced by a blower to pass under pressure through the adsorbent bed. The nitrogen, carbon dioxide and water in the air are adsorbed by the adsorbent, and the remaining components pass through the absorbent for richer oxygen. And then as the pressure is being lowered, the nitrogen, carbon dioxide and water adsorbed on the adsorbent are released and the adsorbent can be regenerated in this way. The reciprocating process makes up the basic principle of vacuum pressure swing adsorption oxygen generation.