Patent ID: 7736132

Claim:
A portable oxygen concentrator, comprising: (a) a plurality of sieve beds for adsorbing nitrogen from air, the sieve beds comprising air inlet/outlet ends and oxygen inlet/outlet ends; (b) at least one reservoir communicating with the oxygen inlet/outlet ends of the sieve beds for storing oxygen exiting from the oxygen inlet/outlet ends of the sieve beds; and (c) a compressor for delivering air at one or more desired pressures to the air inlet/outlet ends of the sieve beds, the compressor comprising: (1) a motor, (2) a crankshaft coupled to the motor defining a central axis, (3) three diaphragm assemblies, each including a flexible diaphragm, spaced apart around the central axis, wherein the diaphragms in three diaphragm assemblies are substantially coplanar with one another, and wherein a plane in which the three diaphragm assemblies are located is generally perpendicular to the central axis, and (4) three rods extending between respective flexible diaphragms and the crankshaft, and wherein the three rods are coupled to the crankshaft such that the three rods are offset axially from one another along the central axis.