What is a sieve bed in an oxygen concentrator?

A sieve bed is the filter inside the oxygen concentrator which separates out the nitrogen from the oxygen in the air. This sieve bed uses a material called Zeolite to collect all the nitrogen in the air. Typically a concentrator has two of these sieve beds with one of them always working to collect nitrogen and the other is removing the extra nitrogen it has already collected. The two sieve beds switch jobs every few minutes automatically, in a completely sustainable ongoing process.