Working Principle of Portable Oxygen Concentrator

How does a small portable oxygen concentrator reach same effect as big home units?

In last bog, we know that as soon as you start machine, oxygen concentration processing won’t stop and provide oxygen continuously. And big home units can produce enough oxygen based on their big compressor and PSA system. So how does a small POC can provide same oxygen as big home units? It's not reasonable, right?

Just think of our breath in and breath out. Actually we have a part of oxygen wasted based on continuous oxygen flow when we breath out. So technicians started to think whether we can save this part of oxygen when we breath out, and deliver the stocked oxygen in people's next inhalation. Based on this principle, technician developed a system for storing oxygen which given by PSA system continuously. The oxygen storing system deliver oxygen when user breath in and stop supplement when user breath out. Here is the principle of pulse flow comes from. 

Due to breath ratio of exhalation and inhalation is 2:1 for normal people, a people who use 5 liters home oxygen concentrator actually just inhale a third of its oxygen flow. In other words, if a machine adopt the principle of pulse flow can reach same effect with oxygen capacity of a third of 5 liters continuous flow. Besides, there is another part of oxygen during inhalation stays in our trachea which is wasted. 

Based on research and clinical testings of oxygen therapy at home, pulse flow deliver 210 mililiters oxygen dosages can reach the same effect of 1 liters continuous flow. Here is the equal effect that we can see normal in description of pulse flow.

But in the following decade of usage research, we can see many users complianed the small POCs can't provide enough oxygen. This is particularly evident in patients with moderate lung diseases. There were mainly two reasons ignored for old POCs. On the one hand, the oxygen demand is not a fix amount and it can increase any time according to development of illness and the increase of activities. On the other hand, people in moderate stages of illness are less tolerant for hypoxia of less than 80%.

According to the newest research, a larger oxygen dosages of 330 mililiters can better meet demands of oxygen therapy. Especially when we go outside with increased activities. Here is how the other designs of oxygen bolus 330 militers comes in the pusel flow of POCs.