A device for producing purified oxygen, has a feed (1, 1′) of a mixture of oxygen and argon, and has at least one bed (2, 2A, 2B) of oxygen adsorption material, a purge (3, 3′) for discharging the separated argon and a circuit (4, 4′) for injecting a portion of the purified oxygen produced, into the feed (1, 1′). The device has a programmable logic controller (PLC) for treating the degree of purity and/or the production flow rate that can be set by the user and a control of said purge (3, 3′) as a function of the degree of purity of the purified oxygen and/or of the production flow rate which are desired by the user.