Patent ID: 7766010

Claim:
A method of providing concentrated oxygen product gas to a patient, the method comprising: producing product gas by a vacuum swing adsorption (VSA) process with an oxygen concentrator comprising a plurality of separation columns connected to a vacuum source driven by a motor, wherein the VSA process comprises: (a) introducing ambient air at atmospheric pressure into a first end of a column containing an adsorbent material that preferentially adsorbs nitrogen and removes oxygen-rich product gas out a second end of the column; (b) evacuating the column through the first end to remove adsorbed gas from the column; (c) repressurizing the column by introducing ambient air into the first end of the column until pressure within the column is near 1.0 atm; and (d) repeating steps (a)-(c); pumping product gas separated by the concentrator to a product reservoir; sensing the pressure of the product gas in the reservoir; controlling the speed of the motor based on the sensed pressure in the reservoir to control a rate of which product gas is produced by the VSA process; and delivering product gas to the patient.