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Demand valve


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Do you find it effortless to breath out into the mask when using a demand valve?


With a simple mask,it is easy for me,


With a cluster headache mask 3Lbag I find it more difficult to breath out as the outlet hole is too small and I have to force it out through a relatively small opening. It is clean and 100% assembled correctly , but I do 40LPM at the beginning and that opening is just too small to force the air out.It is easy to breath in at 40LPM becasue the air is being pushed in the mask through the same size opening , but breathing out is done through the same size hole. I will  use  a splitter at the outlet to get 2 holes and see if that help.


How does it work with a demand valve --the breathing out part , is it completely effortless ? or you have to push it out little bit, force it out. ? at 35 to 40 LPM



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john', I can't answer either of your questions.  Unrelatedly, I will mention that with the Optimask, there were some reported issues with high-flow O2 leaking out the back, out the exhale port during inhales.  It's illustrated here, and what to do about it (put your hand over that port), starting at about 5:30:

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 I don' t think that air leaking out during exhales is a problem or a design flaw.  It is designed like this on purpose,otherwise the bag would just burst or the connections would disconnect .  


 Oxygen that you can'l breath in your lungs from the tank must go out and the easiest way for that excess O2 is though that exit valve.

If he is not emptying his bag when breathing in ,he doesn't have to cover that hole because you cant breath in any air at all.It is one way valve only . If you put a mask on tight with no 02 flowing  you cant breath in any air at all .


Also while that excess oxygen is flowing out there is no mixture with the outside air. You dont have to cover that exit hole. 

O2 will flow out thru that exit hole only if you can't breath in anymore O2 . So it is a safety valve too.

When oxygen is flowing out there is no air flowing in ,because nothing is forcing outside air in . New O2 is consistently being pumped in. 


Also at 6:20 you can hear him breathing out and even for him it takes too long . You can hear him pushing it out but it takes him about  4 seconds.  Without a mask it is 2s if you want to force it out the same way.


There is nothing really wrong with the valve , it is just a  piece of rubber. The only problem is that is is not too flexible, so you have to force it out . What would help is a different material that is not flexible. I'll try 2 outlets.




mi12 could you test this:

Breath in O2 and breath out with a mask, measure how long you take when forcing it out

 Breath in O2 and breath out in the mask. measure how long you take 


Is it about 3s out with a mask and 1.5s out without a mask at 35-40LPM  for me

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