Oxygen Systems

[SkyHawk-N]

Anyone got any recommendations for portable oxygen systems?

I'm looking for a compact kit which will provide 2 people with a supplimental supply for approx 6 hours at altitudes between 10,000 and 13,000 feet AMSL. This is the product I've been looking at O2D2- EDS 2-Place (http://www.mhoxygen.com/index.phtml?nav_id=28&product_id=421) , anyone had any experience of it?

Thanks.

[S-Works]

PM Me, I am a dealer for there kit, but instead of importing US spec cylinders which can't be legally filled or tested in Europe I supply European DIN477-9 cylinders.

[SkyHawk-N]

Bose, I'm actually after US spec. products as it will be used over there.

I'm interested in hearing about how it works in reality, how long tanks last, how much it costs to get them refilled and how many places can do it, any difference between masks and canullas, that sort of stuff. I've read the sales blurb and it all sounds very good.

[S-Works]

Then buy the O2D2 unit. I have a 2l kevlar cylinder as my main cylinder and at 230bar it gives me 26 man hours.

Important to remember that European cylinders are higher pressure for the same size and so last longer.

[rosti]

I use a portable kit from o-pur. 2x110l bottles, regulator, mask and nostril tubes for 359 euros. Further throw-away 110l bottles are 57 euros each. No problems with finding a refilling station - just order by post. At 12000ft 2l/min seems to be ok.

http://www.opur.de/

click on 'shop'

[IO540]

Oh dear....

instead of importing US spec cylinders which can't be legally filled or tested in Europe

Reference please bose x

I have been flying with oxygen, airways to FL190, for 3 years. Some basic facts:

- usually no way to get refilled away from base (don't I know it)
- usually no way to get refilled around Europe (likewise)
- the MH kit is good from the gas conservation angle (I've just been involved in very comprehensive airborne tests of different demand regulators) but that's not the whole picture
- the American 540 thread bottles are the most common by far
- having your own rented bottle from British Oxygen (with welding oxygen - it's all the same gas inside, only the paperwork differs) is the best and by far the cheapest way to refill your kit
- the cylinder pressure is a moot point since the only way to exceed 150 bar significantly is by having access to an oxygen boost pump, and by using special bottles and 1st stage regulators...

[S-Works]

IO dont be such a git. You know perfectly well I am qualified to comment on this subject and YOU are not. All cylinders require a CE mark to be filled in Europe. Check the HSE site and the CE marking site.

We have also talked about the use of welding oxygen. Yes it is the same stuff at the tap, but not guaranteed to be the same stuff in the bottle.

[ericferret]

How do the airlines maintain their cylinders as they are all Scott manufactured in the States?

[Fitter2]

Reading various comments on this site, my only advice is talk to someone who knows what they are actually talking about.

For instance, I filled a Balloon pilot's US DOT certified cylinder (tested in UK 2 years ago) to 200 Bar this afternoon.

Some MH cylinders (with CGA540 threads) are rated to 200 bar, most to 137Bar or 2000psi to the old fashioned.

And I agree, the MH EDS systems are by far the most efficient and convenient sytems off the shelf.

Drager (and other) German steel cylinders are OK, and MH systems available to match the DIN477 thread, but they are awfully heavy.

[S-Works]

I have been testing and filling cylinders for 20 years. We are an IDEST and HSE approved test facility for all cylinders as well as O2 filling station. Does that make make competent to talk about cylinders?

[Fitter2]

My CFI used to say experience is what tells you you made the same mistake again. (and in that case, the two consecutive same words makes grammatical sense).

[IO540]

I can confirm I never had any trouble getting 540 threaded bottles tested, and in the very unlikely case of being able to find anybody who can fill them (scuba shops are close to useless for this, I have found) one is far more likely to be able to fill a 540 bottle than anything else.

I do also carry a 540 to UK bullnose BOC bottle adapter but it doesn't get used, except when filling from a big BOC bottle and I got a hose made up for that anyway. DIY refilling is the only practical way for regular flyers.

The MH kit is very good for oxygen usage but has two drawbacks: when the batteries go flat, it fails SHUT (no oxygen), and the short but intense oxygen pulses are not as comfortable up the nose as the other systems.

Having used the Precise Flow mechanical demand reg kit for a while, I would probably buy the MH kit now, on balance, but would get it wired to the aircraft electrics (as well as having the batteries inside) and would get two of the demand regulators for redundancy.

The bottles I got from Aerox are U.S. Catalina cylinders which are either scuba or medical types, resold into the aviation market. They are rated to 200 bar but there is no way to fill a number of them to 200 bar when the BOC source bottle holds the stuff at 200 bar :)

[ericferret]

Out of interest Bose x do you have EASA approval for aircraft cylinders?

[S-Works]

I can provide aircraft spec cylinders with appropriate paperwork but they have to be fitted by an LAE. I can't supply fitted O2 systems only portable.

As far as the comments about what you can and can't fill. Most filling stations will fill a cylinder without checking it, this does not make it legal. I will fill any cylinder that has in date test on it. The IDEST regulations for 2007 and technically do not permit us to test non European cylinders nor fill them. As an interesting point as well we are not allowed to sell non European marked cylinders either. The establishments that are selling them are doing so because they are below the radar. All cylinders actually only come from a couple places, cressi sub makes cylinders in Italy and the others are US based, Luxfor, Hydrotech and Carleton. Carleton make all of the Carbon Fibre and Kevlar cylinders. The carbon cylinders are the preferred option in aviation as they are light and have high working pressures.

The other advantage of using Euro cylinders is that they are 230bar working pressure and will be filled by a SCUBA shop. I can fill O2 to any pressure as I have a Haskel pump that will produce working pressures of up to 400bar. Most technical diving shops have the same set-up. I also manufacture DIN477-9 and CGA540 to DIN477-6 adaptors so that the cylinder can be filled by dive shops. Getting a fill at a dive centre with a strange non Euro cylinder can be hard work. Getting a CE marked cylinder with the correct adaptor is easy.

Filling O2 cylinders is not for the untrained, the SCUBA industry has had it's fair share of accidents when it comes to O2 and air filling. If anyone wants my slide set that I use to teach O2 filling then please PM me, it has some great shots of corpses from those who got it wrong. The best one is of the skin of a guy hanging from a washing line.

There is also the thorny issue of using welding gas. Yes welding gas comes from the same tap as all of the other grades of O2 but thats where it ends. Welding O2 is put in any cylinder that is handy, the cylinders are not vacuumed before filling and the quality or moisture content is not certified. Some will so well they are just refilling what already had O2 in so whats the chance of contamination? Actually what happens is they take any cylinder that is available when they run short and re-spray them to O2 markings and fill them. Aviation grade and Diving grade are the same grade and go through strict quality control. Medical grade is the same but often has the moisture content increased to make it easier on the patient. This moisture is not good for the HP seat on the 1st stage or the solenoid valve in things like the O2D2 kits.

Home filling is an OK solution provided you seek some training on gas handling but it is also a very expensive way of doing it especially getting cylinders from BOC who are one of the dew places that will rent cylinders to individuals. The starting pressure barely makes 200 bar whereas places like Lindi/Air Liquide supply at 230bar and then after a few top ups the working pressure drops. Cylinder rental is expensive as is delivery. Storage of compressed O2 requires notification to you insurance company and the local fire service.

As far as kits go I have several here. The one I have had most success with is the O2D2 unit from MH. They are reliable and very efficient, much more so than the DAN or Aerox kits that I have. Yes the do fail shut but not really a hard ship. The beauty of the MH system is that you can plug any of the kits into the first stage. So I carry a couple of spare flow meters attached to the spare ports of the 1st stage. If the O2D2 failed I would just swap over. At GA heights we have plenty of time!!

The aerox kits are also good, they are reliable and simple to service, but the use only low pressure seats in 1st stages so are a max 137bar fill, this means bigger heavier cylinders for the same gas duration as the O2D2. aerox generally come with a CGA540 thread not a problem as we have CGA540 valves on Euro Spec cylinders and adaptors for filling.

Whilst I am all for overcoming the system of useless bureaucracy that the Europeans force on is one thing I would add is that making a mistake with O2 will cost you your life. As a closing story, I had a friend whose Closed Circuit Rebreather which has an O2 system built in pressurised it too quickly created all three sides of the fire triangle instantly and the 1st stages caught fire (YES METAL BURNS!) and set the unit alight and then the boat.....

[IO540]

Medical grade is the same but often has the moisture content increased to make it easier on the patient.

British Oxygen would definitely differ, bose x. I went through all this on the phone. The gas is the same, only the paperwork differs. No moisture is added.

Incidentally the rental for the biggest bottle from BOC is about £90/year, and a refill (via a swap-out) is about £20. Any welding outlet will be delighted to sign you up; the process is smooth and well organised. The payment is done by direct debit. That bottle lives in my garage (strapped to the wall so it can't fall over) and lasts me a year or two; in fact I end up swapping the bottle for a new one before the outlet pressure falls below the 150 bar destination pressure.

I have tried countless scuba shops. One has to go in under false pretences, and the success depends on how thick the assistant is. If he is clever (not common) he will suss that you are not a diver and won't do it. If he is really thick, we will just do it. If he is halfway, well it's a matter of whether you feel lucky or whether he feels sorry for you. I gave up on the scuba shop scene ages ago - wasted so much time driving around and begging.

The last time was in Greece when we spent a whole day driving around in taxis, being passed from scuba shop to scuba shop and eventually ending up referred to a man who owned a huge oxygen factory and they did it.

It's a waste of time doing it that way.

The safety precautions for oxygen handling are basic and easy to follow. Use the right equipment, the right materials, no grease, and make sure everything is tight. And don't sit on top of the bottle when you are filling it :)

BTW I have an Aerox aviation oxygen bottle right in front of me. The green band goes to 2250psi which is ~ 155 bar, not 137.

Obviously somebody with a helpful scuba shop nearby and who never flies very far will be in a different situation.

[S-Works]

IO, as the yanks say, whatever...... You may be happy to encourage people to risk blowing themselves up, I am not.

I go through around 100 J Cylinders a month in my diving business with our own dedicated account manager with Air Liquide who probably know a damn site more about gas standards than a man with rented welding O2 cylinder in his garage.......

The working pressure of your 1st stage is 137 bar. The first stage is based on a medical oxygen kit and use common parts, the contents gauge should go up to about 180 bar, that does not mean it is safe to use the 1st stage at that pressure. But what would I know......

It also strikes me that you have been unlucky with the dive centre refills, everyone I have supplied cylinders and adaptors to has not had a problem. But then they are filling CE Marked European cylinders with the correct filling adaptor......

[AlsWings]

Excuse my ignorance, but is it possible to buy a scuba cylinder (do they carry branding?) for aero use? Knowing nothing about diving, I assume there would be a difference in capacity/size with the scuba bottles being larger. Would that overcome the problem of re-fills at scuba shops?
On the assumption that one can get refills at a scuba shop, how much does it cost?:)

[BackPacker]

AlsWings, the problem with filling bottles in scuba shops is not so much technical. Yes, you may have to find a conversion adapter but that's usually not the problem.

The problem is that dive shops and schools, as a sort of gentlemens agreement between them, only sell "dangerous" dive goods, including cylinder refills, to people who have a proper divers qualification.

A regular Open Water diver therefore needs to show his license before he gets his bottles filled with air (dehumidified air, but still air). In order to get a 100% oxygen refill, you have to show a qualification as an enriched air diver, or maybe even a technical diver.

Now IO540 pointed out that if you show up with your aviation license, including the "high altitude" endorsement (or whatever) and aviation bottle, some dive shops will fill your bottle. But most won't.

A regular air refill, by the way, is very inexpensive. Something like 2 or 3 euros for a 12-15 liter bottle, up to 200 bar. I don't know about enriched air/oxygen refills.

[IO540]

I used to pay ~ £20 for an o2 refill, 13 cu ft at 150bar, at scuba shops, though one kind bunch did it for £5.

A refill from my own bottle is of the order of £1-£2. In fact I refill bottles for friends free of charge because the big bottle goes back to BOC after a year or two anyway (just playing safe) so some gas is wasted.

A scuba shop won't be interested in a pilot license, IME.

You can buy aviation cylinders from the usual aviation oxygen shops - mostly in the USA. Aerox, Mountain High, various others. They can be aluminium or composite. My 13 cu ft ally ones weigh 3.3kg; a 47 cu ft kevlar one weighs just 4.7kg.

[AlsWings]

The problem is that dive shops and schools, as a sort of gentlemens agreement between them, only sell "dangerous" dive goods, including cylinder refills, to people who have a proper divers qualification.

Hmmm not ideal for the aviator.

Bose, as a supplier of the MH kit is there an 'approved' list of oxygen suppliers - aviation or otherwise - for the UK? I am keen to get a oxygen system, but it seems the re-fill is not so straight forward. To be honest I am not that taken by the idea of DIY refills, but is there another practical solution? I understand some GA fields do refills, Biggin is one, but I believe that is circa £70 for the privlidge.

Bose, in your earlier post (quote below) you mention about swapping over to the 1st stage. Does that mean if in the event of O2D2 failure you can make the system constant flow?:confused:

They are reliable and very efficient, much more so than the DAN or Aerox kits that I have. Yes the do fail shut but not really a hard ship. The beauty of the MH system is that you can plug any of the kits into the first stage. So I carry a couple of spare flow meters attached to the spare ports of the 1st stage. If the O2D2 failed I would just swap over. At GA heights we have plenty of time!!

[IO540]

Biggin charged me £75 but I don't remember who that was.

Nobody really caters specifically for the private unpressurised IFR scene - in Europe it is far too small. So, the general procedure for filling at airports is to find a maintenance facility which does refills of bizjet emergency oxygen tanks. This is fairly rare but they do exist at many big ones - you just have to find them, which is potentially difficult since the stuff is all airside and the last thing you can do at big airports is go for a walkabout airside, poking your nose into one hangar after another. You need the right sort of filling adapter and it isn't a 540 nor anything to do with scuba. It's a small threaded fitting - I wish I had the details. A maint shop near where my plane lives does this refilling (so I discovered just after getting myself sorted with the rented BOC bottle) but he only caters for planes with this special fitting, which I gather is standard in the bizjet world.

What Bose means is that the MH kit uses simple bare-pipe fittings which enable a constant flow cannula to be plugged directly into the first stage regulator. You still need a flow adjuster of some sort in the cannula pipe because the 1st stage output is ~ 20-30psi and if you just poke a cannula into that, the gas will be gone in no time. This is what I do - I have two demand regulators, plus some constant flow (Oxysaver) cannulas which serve as either a backup in case the demand reg(s) jammed, or to serve rear seat passengers.

[IanSeager]

Does that mean if in the event of O2D2 failure you can make the system constant flow?

I use the MH O2D2 kit, and yes, you can plug a constant flow mask/cannula into the adapter (the one attached to the bottle). This would bypass the O2D2 in case of failure.

I got my kit (MH O2D2, bottle etc.) from AFE Oxford. They also do the refills 'while you wait' at £20 a time.

Ian

[S-Works]

In answer to IO540's question the O2 fitting he is searching for a name for is generally a 1/4NPT thread fitting on american aircraft and and either a 1/4BSP or 1/4 Swage fitting in Europe. I have adaptors for those as well.....

The O2DT kit requires a first stage and the standard first stage has 4 ports with quick connect self seal ports. The MH oxysaver kits use flow meters and oxysaver cannula and these will plug into the ports. So you on a 4 port regulator you could have 2 people using the O2D2 and 3 people using oxysaver kits. In the even of a failure you switch to Oxysaver kits.

As far as O2 is concerned, if you take a Euro spec cylinder with a DIN477-9 fitting or CGA540 and a bullnose convertor to any gas station you will be able to get it filled for a couple of quid with the correct grade of gas. Linde Gas, Air Liquide, BOC etc. If you want paperwork to get fills from a SCUBA shop then I run basic nitrox courses, non diving just half a day in the classroom that will give you a cert to hand to a dive shop if they are really being that anal over filling. Saying that IO is the only person I know to have had a problem!

To fill a standard O2 bottle should not cost you more than a fiver anywhere which is 100 times the actual cost of the gas but will be covering cylinder rental etc.

Anyone who wants a fill is welcome to fly into me and get a fill while they wait for a fiver.

I hope that helps.