Combine this device with Oxyarms and nobody will want pressurization in his piston aircraft any longer...
I would prefer a pressurized plane. With 2 cylinders in 2 different places ( home and EDQT), I have no issues to fill them.
With 2 cylinders in 2 different places ( home and EDQT), I have no issues to fill them.
How do you get them filled, by who and how much? The problem with writing "no issues" is that people reading the thread don't learn from it.
I would prefer a pressurized plane
We all would 
But not everybody can afford one, or not everybody wants the mission capability tradeoffs, so that's not a solution to the matter in hand.
Oxygen is a great solution to private IFR in Europe, for the "PA28-181" (ceiling ~14k) all the way through to the "few hundred k €" (ceiling ~20k to ~25k) machinery which is what is mostly used by IR holders.
Renting a cylinder of medical oxygen (white) is trivial and you can do that everywhere in Europe. I have bought mine from a company with a plant next to my house so where ever I fly, I can breathe my home oxygen Finding the equipment to connect the cylinder to the airplane's bottle is less trivial but Mountain High has most adapters. Doing the actual job is not difficult either and if one doesn't feel qualified, it's easy to find somebody that is and will happily do it for you.
There used to be (and still is) aviation oxygen and some people still think only this type of oxygen is allowed for planes. Of course it is next to impossible to find but that is all BS. You can even buy welding oxygen, it's the same stuff nowadays but why would you if the white bottles don't cost much more. I pay 33 € per refill of my 200l cylinder and I guess my next refill will be due to 2015 I would not talk about airplane usage, just get a cylinder with medical oxygen, if they ask it's for your 250kg aunt.
I don't know the situation across EU but I guess you can get O2 fill in any decent scuba shop that provides fills for technical divers.
It seems to cost a bit more here in the UK, but also there is a charge for collection/delivery (£40). We have a pub across the road from our house and they get regular deliveries of some gas (to make the drinks fizzy?) and when I asked about o2 the man said he can do o2 but they are required to make a special trip because he is not allowed to mix o2 cylinders on the same vehicle... Also he would not carry it to where I keep it (in another building), and it's too heavy for me to move other than by rolling (vertical or horizontal). Plus I'd have to stay at home all day because they won't give a time when they will come.
So I have been using welding oxygen from a local welding gas depot, where they swap a cylinder you turn up with in a trailer, no hassle at all and no questions asked. But I have no such facility for anything other than welding oxygen.
Others have developed other ways. One man I know uses gas from a local hospital 
Scuba shops often work, but it's random. Currently I have a local one that works (didn't work for years; before that it worked for a while).
A generator could be left in the back of the plane and "forgotten" - just like a fitted oxygen system. The only other "equipment" would be the four oximiser cannulas. In fact I can see one could install the plastic pipes and connectors (a trivial cosmetic/minor mod) neatly and end up with something exactly like a fitted oxygen system.
Personally I have too much investment in what I have but if I was starting from scratch I would definitely consider this option.
But I have no such facility for anything other than welding oxygen.
I am surprised. Usually gas companies carry the whole lot. Every hospital has a high demand of oxygen. Usually they have a big tank which gets filled directly from a vehicle but for backup purposes they also have a collection of 200l cylinders which they constantly have to refresh (every 12 months I think)
The largest gas company here is Linde with outlets all across the country. In the UK they operate under the BOC (British Oxygen Company) brand name. A quick look at their website shows that they have an outlet 21 miles from Shoreham.
Welding oxygen is fine, too. I live close to a large oxygen production plant and I have taken a closer look. It is the very same stuff these days, would be too costly to have a separate production line producing lower quality welding oxygen. Medical oxygen was 33 € and welding oxygen some 25 € so I went for the "purer" stuff.
The 200l cylinders are too heavy to carry on your own but easy to manage with one person helping you. It didn't fit in my convertible but luckily I had a friend helping and he's got a Passat station wagon. You should get a corresponding cart of course.
A generator could be left in the back of the plane and "forgotten" - just like a fitted oxygen system.
That technology has a long way to go. Too power hungry, too big, too heavy and not enough output. It really makes sense when one can enrich the cabin air so that cannulas/masks are not required. This could be the future of piston GA airplanes as designing a pressurized cabin is next to impossible nowadays with the strict certification requirements.
Personally I have too much investment in what I have but if I was starting from scratch I would definitely consider this option.
With a built in bottle neatly stowed in the tailcone, my investment was the transfilling adapter and the bottle. You'd still need a backup system with a bottle in case your generator fails which further increases the investment.
That technology has a long way to go. Too power hungry, too big, too heavy and not enough output.
I have not seen test results with more than 1 person. For 1 person, the effectiveness is proven.
It really makes sense when one can enrich the cabin air so that cannulas/masks are not required.
Is that feasible?
You are screwed by the law of partial gas pressures.
Let's say the overall air pressure is 8psi (around FL180). 21% of this is due to oxygen, so the oxygen pressure is 21% of 8 i.e. 2psi.
If you now start pumping oxygen into the cockpit, and do enough of it to compensate for the reduced air pressure, and let's say you need to increase the oxygen % from 21% to 40% to achieve the same blood o2 % (sounds plausible, since the air pressure has halved), you will now have oxygen pressure in the cockpit of 40% of 8psi e.g. 3.2psi.
But the outside oxygen pressure is 2psi so you will have 1.2psi of oxygen trying to escape, and that is a huge pressure differential. The oxygen will be escaping rapidly through every orifice. It will push its way out through the heating / ventilating air inlets at a rapid flow rate, plus past the control linkages etc.
The cockpit won't actually be "pressurised" (much) because, similarly, the partial pressure of nitrogen (which is being depleted inside the cockpit) will work the other way round and the stuff will be trying to push its way in from the outside.
It's not going to work. You would need a huge gas output, to pressurise the cockpit by 1.2psi with oxygen, given all the leaks.
designing a pressurized cabin is next to impossible nowadays with the strict certification requirements.
IMHO, the stopper is not certification (everybody knows how to design a pressurised hull, and there is nothing later than WW2 in a PA46 hull) but the lack of demand in GA. A PA46 is still in production but it's a niche product, and very expensive, and every other pressurised hull in current production (AFAIK) has been combined with a TP or jet engine(s) which jacks up the price massively but it enables Marketing to load up the product with goodies because the price tag can now carry them.
You'd still need a backup system with a bottle in case your generator fails which further increases the investment.
I agree; that's why I haven't done anything about it.
How do you get them filled, by who and how much? The problem with writing "no issues" is that people reading the thread don't learn from it.
Sorry, my post was misleading. I have 2 big cylinders based in EGBE and EDQT, to refill my smaller portable cylinders. Most of my flights origin or end at these bases, soI have no need to fill elsewhere. I was not very lucky with scuba shops in UK or Germany, thats the reason for my own refill site. I considered a booster pump, but it is too expensive compared to the gain.
Welding oxygen is fine, too. I live close to a large oxygen production plant and I have taken a closer look. It is the very same stuff these days, would be too costly to have a separate production line producing lower quality welding oxygen. Medical oxygen was 33 € and welding oxygen some 25 € so I went for the "purer" stuff.
The key difference between welding and medical oxygen is the certificate of purity (i.e. the piece of paper). The requirement for purity is much higher for welding oxygen than for medical, but the potential consequence for a missfilled bottle (or a refill of a contaminated bottle) is much higher for medical.
It really makes sense when one can enrich the cabin air so that cannulas/masks are not required. This could be the future of piston GA airplanes as designing a pressurized cabin is next to impossible nowadays with the strict certification requirements.
One would need an enormous flow rate, think of the airflow into and out of the cockpit (the various air vents and leaks). You would need to concentrate 5 times that volume of air to keep an enriched flow rate going into the aircraft and you would need to ensure the only material inflow was from the concentrator - it would require a much higher volume pump than pressurisation (but not the pressure vessel)
There is another Sequal Eclipse oxygen concentrator on Ebay for £900.
This is interesting because it shows there is a more or less constant flow (no pun intended) of these expensive things coming out of (probably) military hospitals.
I've updated my original oxygen article here with some info on these oxygen concentrators.
They remain interesting for sole pilot use - they can't do multiple pilots and don't work with demand regulators.
