The "process" is.....Under pressure (typically over 7 barG) a carbon molecular sieve inside the process vessels adsorbs (adsorb with a "D" not a "B") oxygen molecules and allow nitrogen and other inerts to flow thru. Once the CMS is saturated, the vessel depressurizes to desorb the cms material. In this process, the beds "swing" from one to another. When one is generating, the other is regenerating. Product N2 flows into a process tank in order to produce a consistent purity. The purity coming off the process at the beginning of the cycle is higher than at the end....so a mixing tank is critical. These are NOT storage tanks. PSA's have been around since the late 1970's. They have a useful life of around 7-10 years with some exceptions on both ends (longer and shorter). The vast majority of companies in this business today were not selling PSA's 10 years ago. The original companies selling them 50+ years ago (C.M Kemp, CarboTech, and a few others) are for the most part gone. However Generon is one that still exists and has been around a very long time. What this nice fella called "hearing the machine surge" was actually the desorb process, which follows a brief 2 second equalization of the beds to save air. This is indicative of this business today. A lot of established air companies are relative newcomers to selling PSA's. They typically are not fully knowledgeable in the product, it's history, or the process. It's too bad really. Hope that helps.

@@rds990 That helps my understanding quite a bit, so long as it's not abhorrently wrong to say "it's essentially an upscaled medical oxygen concentrator optimized to collect what would be the rejected gasses. Namely nitrogen, given its abundance, and with the other unreactives treated as unimportant trace contaminants, at least in so far as apropos general industry is concerned.". I had not actually anticipated a competent answer, and had become distracted between my comment and the research time you've saved me by offering a crash course from an obviously knowledgeable source, and am most grateful for your time. I would have thought the process would be one that's more selective of nitrogen, rather than exclusive of oxygen, but thinking on it now it's obvious that trying to be selective to the rather unreactive gasses would probably need to be a lot more chemically and thermally involved than a man in a polo and a cell phone cameraman would be allowed around.