Ambulatory oxygen concentrator

Abstract

An oxygen concentrator provides ambulatory oxygen utilizing a vacuum swing adsorption (VSA) oxygen separator powered by a power pack. The separator has a plurality of nitrogen-selective adsorbent beds, each operating in VSA cycles including feed, evacuation and repressurization phases. The concentrator also contains a delivery system for receiving oxygen produced by the VSA separator.

1 . An oxygen concentrator which produces a product gas containing at least about eighty-five percent oxygen by utilizing a vacuum swing adsorption (VSA) process comprising:
 a gas input system for supplying ambient air;   a VSA gas separation system in communication with the gas input system to receive the ambient air, the gas separation system comprising a cartridge containing an adsorbent material for producing oxygen;   a delivery system for receiving oxygen produced by the gas separation system;   a drive which actuates the delivery system and the gas separation system;   a power pack connected to the drive; and   wherein the oxygen concentrator has a weight of less than 2.3 kg and a volume of less than 1 liter.   
     
     
         2 . The oxygen concentrator of  claim 1  wherein the VSA gas separation system further comprises a vacuum pump which evacuates nitrogen rich gas from the adsorbent material. 
     
     
         3 . The oxygen concentrator of  claim 1  wherein the power pack comprises a battery. 
     
     
         4 . The oxygen concentrator of  claim 1  wherein the delivery system includes an oxygen conserver. 
     
     
         5 . A method of providing oxygen separated from ambient air to a patient, the method comprising:
 performing vacuum swing adsorption cycles in each of a plurality of adsorbent beds containing an adsorbent selective for nitrogen, each cycle including a feed phase, an evacuation phase, and a repressurization phase; wherein the pressure throughout the vacuum swing adsorption cycles does not rise above that of ambient air; and   delivering product gas containing oxygen separated by the vacuum swing adsorption cycles to the patient.   
     
     
         6 . The method of  claim 5  wherein vacuum levels in the beds during cycles are between about 0.1 atm and about 1.0 atm. 
     
     
         7 . The method of  claim 5  wherein each of the beds has a first end and a second end. 
     
     
         8 . The method of  claim 7  wherein during the feed phase ambient air at about 1.0 atm is introduced into the first end of the bed and product gas is removed from the bed through the second end of the bed. 
     
     
         9 . The method of  claim 8  wherein the feed cycle is terminated when a mass transfer zone has reached a specific position in the column. 
     
     
         10 . The method of  claim 7  wherein during the repressurization phase, the bed is partially repressurized by product gas introduced through the second end. 
     
     
         11 . The method of  claim 10  wherein during the repressurization phase the bed is repressurized to near 1.0 atm with ambient air introduced through the first end. 
     
     
         12 . The method of  claim 5  and further comprising:
 controlling cycle rate of the vacuum swing adsorption cycles as a function of the product gas delivered to the patient. 
 
     
     
         13 . The method of  claim 5  wherein delivering product gas comprises delivering a pulse of product gas in response inhalation by the patient. 
     
     
         14 . The method of  claim 5  wherein plurality of adsorbent beds comprises at least two adsorbent beds, each in a different phase at any given instant. 
     
     
         15 . The method of  claim 12  wherein the adsorbent is LiLSX adsorbent. 
     
     
         16 . An oxygen concentrator comprising:
 a portable power pack;   a vacuum swing adsorption (VSA) oxygen separator powered by the power pack and having a plurality of nitrogen-selective adsorbent beds, each bed operating in VSA cycles including feed, evacuation and repressurization phases, the VSA cycles operating with vacuum levels within in a range between about 0.1 atm and about 1.0 atm, wherein the pressure throughout the VSA cycles does not exceed about 1.0 atm; and   a delivery system for receiving oxygen provide bye the gas separation system.   
     
     
         17 . The oxygen concentrator of  claim 16  wherein the power pack, the VSA oxygen separator, and the delivery system have a combined mass of less than 2.3 kg. 
     
     
         18 . The oxygen concentrator of  claim 16  wherein the VSA oxygen separator comprises:
 an ambient air inlet; 
 a vacuum pump; and 
 a valve for selectively connecting the ambient air inlet, the vacuum pump and the delivery system to the adsorbent beds during different phases of the VSA cycles. 
 
     
     
         19 . The oxygen concentrator of  claim 16  wherein the VSA oxygen concentrator further comprises:
 a motor for driving the valve and the vacuum pump. 
 
     
     
         20 . The oxygen concentrator of  claim 16  wherein the adsorbent beds comprise an LiLSX adsorbent.