Update…
I tested the cheap cannula at FL160, and found it delivered the same blood o2 % as the MH one.
I guess this result is not unexpected since the cannula tube will only ever have 100% o2 inside it, so its internal diameter (volume of gas stored) is not critical.
What I did find, however, and this was expected, is that you had to breathe a little more “decisively” to trigger the O2D2 regulator to sense the inhalation.
Together with the need to transfer the short regulator-end MH adaptor tube to the cheap cannula (I used a bit of sticky tape for the test) I guess most people won’t bother. But this is a good result for anyone flying with a significant number of passengers who never come back or whose cannulas need to be discarded for some other reason. I normally mark cannulas with the person’s name (for anyone I am likely to fly with again) and wash them in IPA after each flight, dry them, and bag them, so they don’t get wasted.
Peter wrote:
The internal diameter is greater and together with the ridges (why the ridges?)
My guess would be that the ridging allows them to use less material for a particular stiffness compared to uniformly thicker walls.
If you really wanted, you could try mailing several sellers of medical supplies asking them about a particular internal diameter, no ridging, include a picture of cross-section so they understand what’re talking about. I’m assuming the internal diameter is imperial, i.e. it isn’t a whole number in millimeters (meaning I would try sellers in the US instead of the EU). I think it’s unlikely they have them custom made but this could explain the higher price.
PS: A quick search suggests that what you’re looking for is called smooth bore tubing, that is an oxygen cannula with smooth bore tubing.
From here
Some people don’t buy the aircraft that would best suit them because of the €30 ph Eurocontrol charges.
In an eight seater aircraft, providing new MH cannulas to every passenger would be a similar investment.
So, does anyone use cheap Amazon cannulas?
UK has a similar deal than what I got from German Amazon: https://www.amazon.co.uk/Soft-Nasal-Cannula-Oxygen-Transparent/dp/B00I0T4AFO/
And so does France https://www.amazon.fr/canule-nasale-souple-oxyg%C3%A8ne-transparente/dp/B00I0T4AFO/
Neither deliver to Luxembourg, but Luxembourg Post has a remailing service with addresses in France and Germany ;)
lionel wrote:
I just bought a set of 100 cannulas for below 40,- EUR (including shipping)
We crossed. Where did you get them?
We keep crossing! Thank you!
I am actually convinced by the 33p argument! How dare MH charge £9 each?!
I have only my phone so can’t write much, but do a search for amazon cannulas. They don’t work with the O2D2 due to excessive internal diameter.
Ah. So is there any alternative to £9 each from MH?
I’ll take my risk and see if they work with my oxygen generator. They might not work for the same reason as with the 02D2 since they both rely on breath detection to inject oxygen in the inhale period, and the “excessive internal diameter” may interfere with that.
If they don’t work, https://www.amazon.de/gp/product/B00KTDHO2U/ or https://www.amazon.de/gp/offer-listing/B00E68CR8A/ seem to be exactly the ones I got with the generator (but I’ll have to check next time I’m at the airport!) and cost less than 3,- EUR. There are also “many” that cost somewhere between 1,- EUR and 2,- EUR, such as
https://www.amazon.de/Sauerstoffbrille-soft-f%C3%BCr-Erwachsene-Kinder/dp/B0042KXFZG/
https://www.amazon.fr/Lunettes-permet-dinhaler-loxyg%C3%A8ne-concentr%C3%A9/dp/B01E5XZEGM/
https://www.amazon.fr/Oxyg%C3%A8ne-Lunettes-droite-diff%C3%A9rentes-tailles/dp/B00LEJOFKC/
