Nitrox Blending System

Advantages of using continuous blending as compared to partial pressure:

• More cost efficient Nitrox Blending System
• No need for dedicated Nitrox Tanks, you can use regular scuba tanks with removable neoprene tank bands.  Offering more flexibility with regards to tank allocation.
• One hour training, no need for a blender course.
• System is user adjustable from 21% to 39%.  Recommended maximum percent of oxygen is 36%, but permitted up to 40% and still considered safe. (NOAA studies)

Precautions:

• Compressor must use synthetic oil in a well ventilated area to run cool.
• The final filter should be changed per manufacturer’s specification, to avoid oil build up.
• Recommended maximum percent of oxygen is 36%, although NOAA studies say up to 40% is safe.
• When mixing, ALWAYS start the compressor FIRST before opening the oxygen tank.  This is to ensure that oxygen does not enter the compressor which would damage the moving parts.

System design

The system is designed to mix the oxygen and air together in a homogeneous blend of nitrox at the desired percentage mix. Then the blend is compressed to tank pressure though a standard Scuba compressor. At mixtures of less than 40% this can be safely done.

To accomplish this we need a large buffer tank to smooth the pulse intake of a standard piston compressor. Inside the stainless steel buffer tank we have added three mixing chambers to insure the mix is 100% homogeneous. (No rich pockets of oxygen)

At the output of the buffer and blending tube we add an oxygen analyzer to measure the percentage of mix going into the compressor. This is the same mix that the scuba tank is being filled with.

A high speed stream of oxygen is injected into the beginning of the blending tube. This is done through a very small orifice. The amount of oxygen being introduced into the intake air stream can be adjusted with a pressure regulator from a oxygen supply tank.  This gives full control of the mixture from 21% to 40%. The output pressure of the regulator is limited so that no more than 40% can be accidentally generated.

A solenoid has been added so that when the power to the compressor goes off, the supply of oxygen is stopped. This is a safety feature to prevent an excess of oxygen build up during a power outage.