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That is my understanding too, they just certify the impurity levels.

1066 wrote:

Plumose wrote:For testing (and potentially use) welding oxygen isn't that hard to get hold of.
I know divers used to use it to mix breathing gases even though it wasn't officially certified for breathing

Pretty sure it's exactly the same stuff, made in the same place in the same way - The only difference (I believe) is the certified paper trail for the cylinders.

Just the same for something like bolts for a small aero engine. Four HT bolts for about £6 from engineering supplies, exactly the same bolts but in a little cloth bag with a CAA number and they're about £40.

Exactly this. I had some bolts made for a test rig at £2 each and then for production they were £4.50 each despite ordering 2000 instead of 12 because they came with a 3.1 cert. It is just down to traceability.

Just to be clear, a ventilator doesn't need to supply oxygen (some do but that is not their primary function), they supply "PEEP". Positive End Expiratory Pressure. Effectively just pressurised air.

So basically they are CPAPs that are used for sleep apnoea?

dromia wrote:So basically they are CPAPs that are used for sleep apnoea?

Similar but not quite. I use a CPAP coincidentally! The difference is that a CPAP aids a breath by adding pressure above the atmospheric pressure on the outside of your throat. It is triggered by the patient breathing. A ventilator controls the breath entirely with positive pressure on a timer. So a CPAP will only work if you are breathing. A ventilator will work even if you are not.

The other difference is that a CPAP fits over your face or nose. A ventilator fits to a tracheotomy so they cut a hole in your throat to attach it to.

My CPAP is triggered when you turn it on breathing or not.

Pippin89 wrote:Just to be clear, a ventilator doesn't need to supply oxygen (some do but that is not their primary function), they supply "PEEP". Positive End Expiratory Pressure. Effectively just pressurised air.

Very interested in how you get on with this - I know nothing about medical ventilators but my impression is that anything supplied to government bodies is vastly over priced and over complicated.

Dr Briggs found some orthopaedic centres were using artificial hips costing £650 while others used ones that cost £5,000 — despite ‘no evidence of a better outcome’.

Toilet rolls for example, City Hospitals Sunderland NHS Foundation Trust paid £66.72 for a pack of 100, while Pennine Care Foundation Trust paid half that, a mere £34.14, according to the NHS Procurement Atlas of Variation.

Andrex from Sainsburys £28 a hundred.

Typically over-engineered project - This is a solar tracker built as a university project.
https://www.youtube.com/watch?v=myeGsh3xq2E

My "redneck" homemade version - cost about £30.
https://www.youtube.com/watch?v=4w2GX1OXu4w
And this one I use a salad spinner for the gears.
https://www.youtube.com/watch?v=6T-uCl0jrG4

dromia wrote:My CPAP is triggered when you turn it on breathing or not.

If that was the case then you wouldnt be able to breathe out. CPAP is a supportive pressure not a permanent pressure. It probably feels like its breathing for you but if you hold your breath you will find it stops pumping.

Nope mine ramps up to pressure as soon as you turn it on, whether it is on my face or not, there are wee holes in the mask to keep the pressure even when breathing. Just checked it to make sure and it kept pumping couldn't hold my breath for long as the pressure came down my nose keeping the airways open as it is supposed to do.

dromia wrote:Nope mine ramps up to pressure as soon as you turn it on, whether it is on my face or not, there are wee holes in the mask to keep the pressure even when breathing. Just checked it to make sure and it kept pumping couldn't hold my breath for long as the pressure came down my nose keeping the airways open as it is supposed to do.

You might want to get that checked as it definitely not as it is supposed to work... Must be bloody uncomfortable having it force you to breathe!