How Medical Oxygen Concentrator Oxygen Diluter Works
The oxygen diluter works on the principle of rapid pressure swing adsorption of nitrogen in the atmosphere to the zeolite minerals and then releases the nitrogen. Adsorption systems of this type, therefore, function as nitrogen scrubbers to pass other atmospheric gases. This makes oxygen a residual vital gas. PSA technology is a robust and economical technology for the generation of mid-range oxygen in small volumes, with low temperatures being more suitable for higher capacities and external transfer generally more suitable for small volumes. At high pressure, a large amount of nitrogen is adsorbed on the porous zeolite because of its larger than nominal volume. The pressure drop collected after oxygen and the rest of the free components, which allow nitrogen to desorb.
The oxygen diluter has an air compressor, two cylinders filled with zeolite particles, a pressure equalizing reservoir, and some valves and pipes. During the half cycle the cylinder receives air from the compressor, for about 3 seconds in a row. During this time the pressure in the cylinder rises from atmospheric pressure to about ten times the atmospheric pressure (usually 20 psig/138 kPa gauge, or 2.36 atmospheres) and the zeolite becomes saturated with nitrogen. Medical oxygen generators as cylinders reach the verge of pure oxygen (with a small amount of argon, carbon dioxide, water vapor
During the half cycle, the valve opens and gas-enriched oxygen flows to the equalizing reservoir, which connects to the patient's oxygen hose. At the end of half the cycle, there is another valve position change that causes air from the compressor to be directed to the second cylinder. The pressure droplets in the cylinder move into the reservoir as oxygen-rich, allowing nitrogen to be desorbed back into the gas. By means of the second half of the cycle there is another valve position change to vent the gas cylinder back to the ambient atmosphere, keeping the oxygen concentration in the equilibrium reservoir at a pressure below about 90%. The pressure of the medical oxygen concentrator in the hose delivering oxygen from the equalizing reservoir is held firmly through the pressure reducing valve.