One of above links is dead.
See further back up the thread. All oxygen is the same.
Which of the two thread options, depends. If you have your own hose, it doesn’t matter. With scuba shops, DIN is better.
The 48 cu ft cylinder is red lined at 150 bar.
Interesting oxygen pump. They used to be 5k-10k; this one might be less. But the cost of refills is basically irrelevant so wasting half the gas is ok.
How that pump gets 2000psi is awfully interesting 
The effective diameter of the piston must be pretty small. It’s like mountain bike shock pumps; they achieve 250psi with a piston about 1cm diameter and that is with a lot of your weight on it.
pilotrobbie wrote:
Does it have to be aviation oxygen in the bottles or can you fill up with any old oxygen? Which BOC one is best?There’s this
And this
and also this Aviation Oxygen Cylinder but looks to be more expensive (no surprise, given it has the word Aviation in it.)
I am now getting a better of an idea what I need to do. I’ve found an interesting document online about storage of the bottle, the regulations state that you can store in a cage outdoors. Which is what I might do and have it secured with padlock and label the cage that it contains OXYGEN.
But then I was thinking this may be suitable between the fence and the space where we turn the aircraft around at the back of our stand. https://www.diy.com/departments/outsunny-garden-storage-shed-with-lockable-door-sloped-roof-for-bike-grey/5056534545604_BQ.prd
Peter wrote:
But the cost of refills is basically irrelevant so wasting half the gas is ok.
Let me get this bit correct so I am understanding. Presume you use BOC?
You pay a monthly fee to BOC or a one time charge for the bottle any any refill fees?
This one looks good as it’s 300bar. Presume that’ll be more than enough to fill the CFFC-048?
https://www.boconline.co.uk/shop/en/uk/oxygen-300bar-evos-ci-cylinder—-50-litre-1-e50#product1
It says I’d need one of these: https://www.boconline.co.uk/shop/en/uk/boc-evos-single-stage-oxygen-regulator#product1
Which will be the equivalent to your pressure gauge and pressure release valve? Just need then a pipe to a CGA-540 or the DIN447? I presume the BOC uses BS341?
There is no regulation on what you keep at home and where. Well, firearms exceeding 12 ft-lbs
2nd URL above is dud. Too many hyphens; probably needs to be posted as a link.
Normally O2 is in 200 bar cylinders (~3000psi), not 300 bar.
The CCFC-048 is redlined at 150bar.
What about at the aerodrome? Our building we live in has banned gas cylinders etc
On the BOC website type in >>> Oxygen EVOS 300bar Ci Cylinder, Industrial Grade Compressed Gas
https://www.boconline.co.uk/shop/en/uk/gas-a-z/oxygen/
The E33 contains 10.2m3 and the E50 contains 15.5m3 – do you know how to work out how many full refills I am likely to get out of that for the CCFC-048? Would that not solve the issue of having less pressure to fill the CCFC-048?
I am looking to refill with the least amount of needing to go back to BOC, maybe 9-12 refills per year of the CCFC-048.
I presume you use the “Oxygen Cylinder Industrial Grade, Compressed Gas”?
Peter wrote:
There is no regulation on what you keep at home and where. Well, firearms exceeding 12 ft-lbs
2nd URL above is dud. Too many hyphens; probably needs to be posted as a link.
Normally O2 is in 200 bar cylinders (~3000psi), not 300 bar.
The CCFC-048 is redlined at 150bar.
pilotrobbie wrote:
I am looking to refill with the least amount of needing to go back to BOC, maybe 9-12 refills per year of the CCFC-048.
If you mean 9-12 full refills back up to ~150 bar, then I think you need two extra pieces of information to work this out theoretically.
(1) The internal volume of the CCFC-048, which I could not find on the Mountain High website. I only found external dimensions, and estimated the internal volume as follows: Its (external) dimensions are 50cm high x 17.2cm diameter, so I assumed internal dimensions of 45cm x 15.5cm, giving a volume of 0.0085 m^3.
(2) The meaning of 15.5 m^3 of the BOC Evos E50 cylinder. I assumed (because I couldn’t find it on the website or elsewhere) that the volume is quoted for 1 bar and 20°C.
I then worked our how many moles of gas you have in the E50 (using P V = n R T, where P is the pressure in Pascals, V is volume in metres^3, n is the number of moles of gas, T is temperature in Kelvin, and R is the ideal gas constant which has a value of 8.31446261815324 if using the units I just mentioned.) 100’000 Pascals = 1 bar, and 20°C = 293.15 K.
No warranty on my calculations, but I get (100’000 Pascals) * (15.5 m^3) / (293.15 K * 8.31446261815324) = 635.9 moles in the E50
For the CCFC-048 at 150 bar and 35 bar, I get:
150bar: (15’000’000 Pascals) * (0.0085 m^3) / (293.15 K * 8.31446261815324) = 52.3 moles
35bar: (3’500’000 Pascals) * (0.0085 m^3) / (293.15 K * 8.31446261815324) = 12.2 moles
So each full refill is 52.3 – 12.2 = 40.1 moles
Quantity of gas (moles) is linear in the pressure for same volume and temperature (P V = n R T again), so using the E50 from 300 bar to 150 bar should give you 635.9 /2 = ~ 318 moles (at 20°C). So I make that 318 / 40.1 = 7.93 full refills. After that, you would need to partially fill the CCFC-048 or else get an oxygen pump.
Thanks for that very informative piece, let me say 7 refills between each bottle exchange. So it’s probably much more worth it to do it DIY than the costs of visiting a centre or refill location, especially for me as I don’t have a car. So costs are higher for me.
derek wrote:
If you mean 9-12 full refills back up to ~150 bar, then I think you need two extra pieces of information to work this out theoretically.
@Peter with BOC do you do the monthly programme or pay once and pay for any refills?
I pay annual rental and then pay for each bottle swap. In fact due to low usage I have a voucher for a free swap on the wall which I keep forgetting to cash in
The key point is that with a decent size cylinder you don’t need it fill it up full every time you fill it. Unless you fly to Greece all the time with 4 people, at FL180… which none of us do because FL180 implies really crappy wx over a vast area. And the way wx works in general, if FL120-140 is not enough, FL180 also may not be because anything convective will likely have tops ~FL250.
I reckon I would get 10+ “useful” refills of the CCF-48 from the big BOC cylinder.
Peter wrote:
The key point is that with a decent size cylinder you don’t need it fill it up full every time you fill it.
I’d fill up every time so I know I’ve got the range to sit at FL150 each way for 5-6 hours each direction for x2 people. How do you get x4 from the EDS? I thought it’s limited to x2?
Peter wrote:
big BOC cylinder.
Which bottle do you use? I take it the W Oxygen cylinder? (Comes under Oxygen Cylinder Industrial Grade, Compressed Gas) on the website?
1 × 1st stage reg with 4 outputs.
2 x O2D2. And if flying 2-up, you have redundancy.
FL150 2-up for 5hrs will use maybe 10% of the CCF-48. On a solo flight EGKA-LDLO I barely see the change.
Yes, W is the standard welding gas depot size. 200 bar. Everything else is uncommon, and the smaller ones don’t cost much less so the debate would be solely over easier hauling back to the depot.
Recently I went to look for better solutions to these crappy disposable nitrogen cylinders (for gas shock refills) which have leaked out from 1500psi to < 800psi by the time the shysters ship them to you, but the cost isn’t any less than renting the W cylinder…
