Rapid cycle pressure swing adsorption oxygen concentration method and apparatus

An oxygen concentrator comprising:

• a plurality of more than two molecular sieves each sieve having an inlet side and an outlet side;
• a pump having an ambient air intake connected to atmosphere and a high pressure outlet;
• at least one valve assembly having an inlet port connected to the high pressure outlet of the pump, a low pressure outlet port, at least one sieve port connected to the inlet sides of each of the sieves, and inlet side ducts selectively interconnecting the ports such that the inlet side of each of the sieves is connected to the high pressure outlet of the pump during an inlet pressurization subcycle thereof and to the low pressure outlet during an inlet depressurization subcycle thereof;
• and
• a valve control connected to the valve assembly and configured to operate the valve assembly in a cycle that includes alternating the inlet pressurization and depressurization subcycles for each sieve, with each inlet pressurization subcycle being not more than half the duration of the inlet depressurization subcycle of the sieve, with the inlet pressurization subcycles of at least two other sieves of the plurality totally occurring during the inlet depressurization cycle of each sieve.

A rapid pressure swing adsorption oxygen concentrator for producing oxygen of at least ninety percent purity at a rate of in the approximate range of two to five liters per minute, the apparatus comprising:

• an air compressor having a compressor outlet;
• a product outlet;
• a plurality of molecular sieves having a total volume of less than approximately one liter, each sieve having an inlet side and an outlet side;
• outlet-side valves connected to the outlet sides of each of the sieves and the product outlet;
• inlet-side valves connected to the inlet sides of each of the sieves, the air compressor outlet and atmosphere;
• a valve cycle control connected to the inlet-side valves and to the outlet-side valves to operate each of the sieves in a cycle of not longer than approximately twelve seconds with the sieves phased relative to each other at approximately equal intervals around the cycle;
• and
• the valve cycle control being programmed to operate each one of the sieves through a sequence of subcycles, including:
• (a) a venting subcycle of at least four and one-half seconds duration during which the sieve is vented from its inlet side through one of the inlet-side valves and substantially to atmosphere,
• (b) an inlet subcycle during which the sieve is pressurized with air from the compressor outlet through one of the inlet-side valves into the inlet side of said one of the sieves
• (c) an outlet subcycle during which oxygen rich gas is output from the outlet side of said one of the sieves through one of the outlet-side valves to the product outlet,
• (d) a pair of equalization subcycles during which (1) oxygen rich gas is output from the outlet side thereof through one of the outlet-side valves and into the outlet side of one of the other sieves without venting the other sieve from its inlet side to atmosphere, and (2) oxygen rich gas is input to the outlet side of said one of the sieves through one of the outlet-side valves from the outlet side of another one of the sieves without venting said one of the sieves from its inlet side to atmosphere, and
• (e) a pair of purge subcycles during which (1) oxygen rich gas output from the outlet side thereof through one of the outlet-side valves and into the outlet side of one of the other sieves while gas is venting from its inlet side of such other sieve to atmosphere, and (2) oxygen rich gas is input to the outlet side thereof through one of the outlet valves from the outlet side of another one of the sieves while gas
• is venting from the inlet side of said one of the sieves through one of the inlet-side valves to atmosphere and;
• the inlet subcycle (b), the outlet subcycle (c), the equalization subcycles (d)(1) and (d)(2) and the purge subcycle (e)(1) for each one of the sieves collectively occupying a portion of the cycle that is shorter in duration than the venting subcycle (a).