The Process

The system requires an air source to supply air to the membrane for separation. This air source (supply air) can be from high-pressure storage tanks or from a low-pressure compressor. First, the supply air pressure must be reduced to 80-300 PSI for use in the membrane. A regulator is used to adjust the input pressure and volume of nitrox to be made. After the regulator the air travels through filtration to ensure a proper air quality that will not damage or plug the membrane fibers. After the filtration the air is heated to a stable temperature that is constant and optimal for the membrane permeation. This temperature is about 110 degrees F. After the heater the air enters the membrane. The membrane is made up of thousands of hollow fibers. Oxygen permeates faster than nitrogen through these fibers. At the nitrogen outlet there is a fixed orifice that will allow the right amount of nitrogen to escape at maximum output to produce about 44% O2 at the permeate outlet (O2 rich gas). The permeate exits the membrane into a static mixing tube that allows ambient air to mix with permeate. The gas mixture is then analyzed with an inline sensor before delivery to the compressor for compression. As the operator increases the input pressure on the regulator, the volume of nitrox produced is increased as well as the O2% of the total gas mix. Decreasing input pressure will lower the nitrox O2% mix.

After using your nitrox system you will notice that different O2 percentages match certain input pressures. These input pressures will be repeatable. Simply said, if today your compressor pumps 36% O2 when the input pressure to the membrane system is at 126 PSI. The next time you want to produce 36% O2, just adjust the pressure to 126 PSI.