what with the high price of bottle rental now and the gas and the surcharge
i thought this may be possible
my car runs on propane
can I suppose, stick a rubber pipe up the exhaust ........have that going to a vapour seperator.....then into a cheap compressor (who knows ...a tire inflater maybe capable) ...........then into bottles .........
how many Min's of hours welding can be/ maybe possibly held in a large- ish bottle at 120 psi
you may get a slightly shitty weld .but who cares its almost free.
exhaust gas analysis of fuels
Exhaust pipe emissions [g/km] Autogas (LPG) Diesel Petrol
What I don't know about welding would fill a very large book, but I do know something about combustion chemistry.
First of all, most of the exhaust gas would be nitrogen - it represents about 79% of the air going in (or over 70% of the mixture) and, apart from a trivial amount converted into NOx, it ain't going anywhere except out the exhaust. AIUI, MIG welding uses CO2 or argon, the latter being preferred, and since the latter is several times as expensive as nitrogen, I deduce there must be a reason nitrogen is not used, probably as it will form nitrides with some metals and hence local changes in hardness. If I understand you correctly, you quote the exhaust figures in g/km; in order to understand what you have got, you really need to look at the gas concentrations in volume %. That would highlight the glaring hole which is mostly the nitrogen.
Second, there will be some oxygen in the exhaust, from incomplete combustion even if the mixture is exactly stoichiometric. This will obviously be bad news for the weld.
Third, the mixture of water and NOx in the exhaust gas will not do the inside of your pressure bottle a lot of good.
Fourth, the CO in the exhaust would not do you any good if you were welding in a confined space. Some would get oxidised in the arc, but not all.
Sorry to rain on your parade - and give it a go (with suitable precautions), it might work...
I was just going on what those results in the table ..said to me .. co2 there is the dominant gas ... ...so is the table wrong ?
and to get rid of some of the nasties ...i could filter the whole lot through those carbon granules you get from aquarium shops.
and wasn't planning on doing it in a confined area ..it would be well ventilated ....more so, than most MOT garages that just have the front doors open ......
The process of welding gives off lots off CO and other poisonous gases anyway.
As for the stuff, that could rot the cylinder ...there's not much sulphur in the gases from an engine run on lpg.......would the carbon granules filter get rid of what there is left of any potential rust agent . ?
No (at least I have no reason to think it is), just incomplete - exhaust analysis is looking at pollutant levels; nitrogen and oxygen are not considered pollutants. (Though, with bureaucrats who consider stones dug up from farmers' fields as taxable waste, you never know.)
Well, I was talking about NOx - which with water would produce nitric acid and other nasties. Yes, carbon granules would probably absorb both
- until exhausted.
You would probably do better making your own CO2 from marble chippings + acid though.
I don't know ... No ones proved otherwise ...it could give good results ..
May be forced to try it when the next rental period is due
Looked up nitrogen and the exhaust gases .......seems that most of the nitrogen in the air pases strait through the cars combustion process unharmed unchanged .. and nitrogen is as much as a semi inert gas as co2...thats according to what research i could do .
and nitrogen is used as a MIG welding gas ..........particularly as a a gas to fill tubing that is to be welded .
yes, i would like to carry on using argoshield ...but cant justify the expense it costs when i only use one bottle a year.
I'm not arguing ..or saying to people.... do it my way ... I'm just after constructive critisim...........which Ive had so far .so alls well and good. I didn't realize that the nitrogen was the dominant gas ....Dave put me right on this ...and i did a bit more looking on google with that in mind.
information for all
i don't know if people realize now ...........you cant do unrented bottle swaps any more...since the new owners of boc's bottle business (air-liquide) put into place a fool proof system.
so anyone that used to do this is in for a big surprise when or if they task there bottle to be swapped.