British Lung Foundation
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Liquid Oxygen LOX

Hello again, eventually (last Friday) got sorted with a 35litre Dewar and Marathon 850 from Air Liquide.

After safety audit, demonstrating then charging the unit, the technician said to leave it 25-30 minutes until some of the liquid had vaporised before using it, by which time he was miles away.

I have used pulsed (on demand) Oxygen since 2006.

I came to use the unit half hour later and although it was fine on 4lts/min on continuous on pulsed at the same rate (maximum for this unit) all it did was intermittently irrespective of demand.

I contacted AL Monday morning, who said a replacement would be here Tuesday.

At 15:04 Tuesday an AL van pulled up on our front waited 20 seconds and pulled off again.

At 17:00 she who must be obeyed rang AL who advised the unit would be here Wednesday...................I know it's sounding a bit like the "gasman" by F&S..............but she contacted them again on Wednesday. Girl said it had been scheduled for change Tuesday and she'd ring back, this she did, to advise delivery Thursday

Thursday at 11:20 a phone call, "hullo fellah..........where are yer pal?" gave location "sounds like vhe place I waz on Tuesda" it was, I retorted, why didn’t you get out of your van and knock, I asked "couldn’t see vhe 'ouse numba.........only next dors" (wtf?@#!)

Said idiot, (sorry to insult any idiots reading this) put a 10 second burst into unit, told my beloved to leave it 30 minutes said "the ovva guys a pillock.....dunno wot ees takin abowt" left and became "white van man" again.

Never seen the scruffy unkempt life-form before, certainly not the AP calibre we've been used to.

Again the flow rates on continuous are fine 1-6lpm, BUT the unit although functioning (i.e. delivering Oxygen) at 4lpm on demand, gives little O2 when compared with 300 or 400 ltr cylinders with a Conserver or my POC at the same flow rate.

Could any other users please give their experiences of the marathon re: demand flows and from LOX units in general; as on continuous flow I'm getting 3.5-4 hours



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9 Replies

Sorry can't really help you but hopefully someone will be a long soon to help, I use liquid 02 but with a companion the only time I have tried anything different was when on holiday and A L made a cock up giving me a Helios it was pulsed and constant flow but really was not my prescription yes it did 6L continuous but only lasted an hour so not much good for a holiday eh :) Hope someone can help you Val


Sorry I can't help with your specific query but your experience with Air Liquide is typical of my own. I am planning to put together a comprehensive dossier on the failings of this company hopefully with a view to taking it to a high level to present a case of incompetence and a company unfit for purpose. To do this I will clearly have to have detailed times, incidents, responses (or lack of) etc and perhaps some advice from any legal eagles amongst our many readers. Anyone who wishes to support this should make careful notes of any such incidents and I will try to collate and present this to the appropriate authorities.

Very best of luck with your problems

Dear Mr Warwick, you have had your problems, I'm sure the intent was correct on Monday from the call centre; just that they have ONE lazy sod who should be collecting ESA.

Have had to have two 400 cylinders delivered today, this due to the above and leaking HP pipes, not been able to get any since AL took over! and the ones I have are old, well compressed this together with the abysmal connecting procedure

All the time the LOX is boiling away to atmosphere

Compared with say 400 cylinder plus conserver; the LOX set at D4 feels more like 1-2 lpm with resultant reduction in sats.

The former AP tech who delivered this morning has not been trained on LOX and therefore can't help.

SWMBO is keeping a blow by blow account of their actions, as she did with AP

My local Resp team are irate by their actions and charging system.

Keep you all posted


When my prescription was for 2 lpm, the pulsed dose seemed minimal so I always used it on the 'C' setting and it would deliver a reasonable performance at around 4 hours.#

When my prescription was upped to 4 lpm, I have found the 'D' setting (pulsed) sufficient as the 'C' setting would generally expire within an hour or two.

I also had a 'malfunction' in my Helios in that the pulse was very erratic so they changed it and all was well again.

BUT, and this is a very big BUT! The demand function only seems to work well with NEW cannula. If your cannula is over 2 weeks old, the pulsing gets erratic, at least that is my experience. I believe the cannula loses elasticity and restricts flow.

Your driver/tech will supply new cannula on demand so ask for enough to have a fresh one weekly.

Hope this helps,



Thanks I'm trying to comply with what the prescription states and that's 4lts/min ambulatory from cylinders pulsed and further 4 lts/min from concentrator which is continuous.

The LOX was supposed to take over from compressed O2 (in cylinders) only one third of the weight, doesn’t seem much point if the flowrate is so poor that I have to use continuous at 3.5 hours full to empty, instead of >5 hours from a cylinder.

Not rocket science is it really.

From full the 'Helios Marathon' set at 4LPM constant will give you just under 3 hours (2.9 to be precise). On demand, 4LPM gives between 8 -10 hours. As for the - I have only ever heard it on my in-breath, so have no explanation as to why it should happen intermittently irrespective of demand. You didn't state whether this meant you were getting your's to frequently or not often enough. As for the '' itself, while you may only hear it briefly as it starts to deliver, the 02 burst does then quietly continue for as long as your (nasal) in-breath does. As soon as you stop breathing in, the 02 stops. You should have been given a manual / guide when the dewar was first delivered to you. This would give you times of the various flow settings etc.

I don't stick to one particular setting myself as sats vary depending on activity. For example if I am walking empty handed at steady pace I use 4lpm pulsed or constant, but if I am carrying shopping I turn up to 6 constant. When I am pottering around the supermarket I turn it down to 2 and if I sit in the cafe I turn it off. As I rarely walk at fast pace for more than an hour constantly, I find it suits me well and with a little thought it lasts me for a day out and about. I love it and would be dismayed if I had to use cylinders. Today i used my first fill at 6lpm constant to do my morning mile walk and some other exercises. I have now refilled ready to go out and about , so this refill will easily last me until I get home a few hours from now.

If after giving it a few weeks trial you find you cannot get on with it then perhaps you could ask to return to cylinders. As for the AL man not being up to scratch, I believe the staff will be the same staff as previously employed under the last contract. The AL man here in Cornwall is an absolute gem and I have not once had reason to complain. Funnily enough he was telling me when he delivered two days ago, that a holiday maker he had just delivered to expressed her delight at getting an 'AL man' again, as her home area had recently changed over to Dolby Vivisol and they were, she claimed 'diabolical'. Lets hope all areas settle down soon. P.

Good Afternoon Parvati thanks for your precise information and advice, 2.9 hours or 2:54 design is (2.854 hrs) 2:51minutes at setting of 4lpm constant; so the first unit was obviously quite faulty, giving 3.5 and 4 hours so not even consistent in its fault else the flow rate would be 3.26-2.85 lpm at setting of 4, suffice to say that the replacement which could have been here a lot quicker :( we have met over the last six years every AP Tech' in the area, thankful to say had never encountered this scruffy, lazy individual before, I think Jan will probably greet him by the throat next time. Anyway the unit is operating OK.

I will think long and hard before returning to the heavy 400 compressed gas cylinders.

When the composite parts where delivered the technician furnished all the relevant paperwork, nowhere in this paperwork does it advise duration/flowrate at quoted units in filling guide ref:X0928000-03 2012.

What I did come across on the net was a publication referred to in the above; after a good deal of searching was this:

This does give some running times.

I was able to ascertain what the fault was and where it was from another publication.

It also explains the strange modus operandi on demand.

But that is heaavvy reading.

Oh "I came to use the unit half hour later and although it was fine on 4lts/min on continuous on pulsed at the same rate (maximum for this unit) all it did was intermittently irrespective of demand" could hear it on the dining table just spluttering.............hope it been repaired by now it was a former Linde (German) used unit.


I am in Gloucestershire and have AL absolutely no problem, very polite and helpful and always ring about an hour before they arrive. Have borrowed a portable concentrator twice for holidays in our little caravan and it has always arrived on time. I would also like to say that the call takers are always so helpful, cheerful and polite. Perhaps it depends on area.

I think we were spoilt Carole, apart from the long long, long b/hol weekend of HM's 60th celeb's and a none delivery for seven days all was A1 with AP.

Still unable to get the HP (50psig) lines; cylinder to conserver since AL took over.

It'll settle down soon.....or not!

Looking forward to dragging our shed...........sorry towing our caravan next month (when the kids are back in school). Don't know to where yet..............possibly Parvati-land LOL




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