Oxygen flashback problem

[gordon stephenson]

I have just fitted some new to me pipes to my oxy/accet bottles and they have inline type flashback arrestors connected straight after the regulators,However the oxy is not passing any pressure at all, there is still a good amount in the bottle, When i removed the arrestor things worked perfectly and I was welding again, Does not appear to be anything to reset, do these things ever just block up for some reason, And yes the arrestor is fitted with the flow direction correct, Any idea's

Thanks Gordon.

 

[hotrodder]

I've had a flashback arrestor that was marked 'backwards' before. Took it back but if that's not an option and their history is unknown i'd replace both for the sake of £30 ish (in the case of non/auto restable types)

 

[weldequip]

The automatic, in-line flashback arrestors have a limited life. Just try taking that out of the hose line & testing it without...it's possible it's a faulty non-return valve at the torch end...otherwise it's a goosed arrestor
weldequip

 

[chunkolini]

Have you got the arrestor backwards?
I remember setting up an oxy/aceytelene economiser with one component backwards and having a similar problem. Dummy.
As weldequip says try setting it up it without the arrestor, if gas flows on both pipes see if the arrestor can be can be installed thoe other way round mark it with a marker pen as it is then try it the other way round. If it works you are Ok.
Dont use it with out the arrestors though. Mine have never been needed, but if they were................................................................ No house/shed/family/street.

Chunko'.

 

[weldequip]

A full flashback is very rare......but you only get one!
weldequip

 

[gordon stephenson]

Hi Guys
Thank for the replys, Chunko I said in my post"when I removed the arrestor the oxy flowed and the torch worked perfectly" The arrestor is only made to fit the one way round, and as far as I know worked OK in the past.

Thanks Gordon.

 

[wyn]

What make are they Gordon ?

We were told last week at work to go round all the burning gear and chuck away any weldability flashback arrestors. Don't know the reason.

 

[gordon stephenson]

I will check in the morning Wyn and report back.

Thanks Gordon.

Hi, Again,
If it helps,here is the info Wyn requested.

Make:..Murex

Type:..Saffire

Model:...XL 5

Cheers Gordon

Back again, Just managed to find this on the net, Just a little more information.


--------------------------------------------------------------------------------

Saffire XL5 Flashback Arrestors

The latest in the range of Saffire XL cylindrical flashback arrestors, the XL5 is an advanced design giving a high flow rate. Internally the XL5 is equipped with a large cylindrical flame arresting element, an automatic reset, non-return valve and a heat sensitive automatic cut-off.

Automatic reset non-return valve
Heat sensitive cut-off valve
High flow flame arresting element
Inlet filter for internal mechanism
Flashback arrestors should always be used in conjunction with hose check valves as these help to prevent the backflow which leads to flashback.

Gas Service
Part No.
Acetylene 1256308
Propane 1256308
Oxygen 1256309

 

[wyn]

I use those or similar ones... to reset you push the grippy bit of the outer casing upwards the black bit on the top has a green line that then shows it is reset.

I think the bottle needs to be on so the arrestor is under pressure for it to stay in the on position...it can be quite hard to reset under pressure...unless all the ones we use are dodgy

Don't know if that's any help.

 

[gordon stephenson]

No grippy bit on the arrestor, no marks,lines or anything else that would suggest there are any moving parts, there is a picture of it on the murex site,

http://www.murexwelding.co.uk/mrxcont/gas/mrxgcse.htm

Cheers Gordon.

 

[weldequip]

The XL5 is not re-settable, the one described by Wyn (with the "grippy" thing) is a re-settable type
weldequip

 

[Hitch]

Good chance its gone then, certain types are disposable. BOC standard ones are, the premier ones are resettable. We use the disposables.


As already mentioned, they are directional. Other thought, was the hoses, have you got them on the right way? They have a check valve in them aswell.

 

[Stuggi]

Non-resettable, ergo, they are made so that if you get a flashback they burn out and doesn't pass gas (phun unintended), just chuck both of them and get a new set if they aren't brand spanking new. If they are, go flame a bit at your vendor.

As per getting them the wrong way around; that's impossible. They have two different fittings, so you can't fit them the wrong way around, and they have different handed treads as well so you can't fit the oxygen equipment on the acetylene and vice versa.

The reason they make the resettable ones is because most professional welders (at least here in Finland) just remove the non-resettable ones and weld without if they burn out and they don't have spares handy.

 

[Pnumac]

The reason they make the resettable ones is because most professional welders (at least here in Finland) just remove the non-resettable ones and weld without if they burn out and they don't have spares handy.

Terve Stuggi
Hmm no FBA? not a good idea at all, even if its an inline one

 

[Stuggi]

Terve Terve Pnumac!

Yeah, I know, extremely stupid since a proper flashback could blow a shop down. Personally I've never seen it, but many shipyard welders and equipment salesmen have told me so.

BTW; where have you picked up on Finnish? Not many finns walking around in the Highlands I would imagine.

 

[Wozzaaah]

What make are they Gordon ?

We were told last week at work to go round all the burning gear and chuck away any weldability flashback arrestors. Don't know the reason.

Here ya go Wyn

 

[Welderpaul]

Brown trousering. What's a set of the in-line resettable FBA's cost these days??

 

[weldequip]

Less than legal action resulting in using sh1te copies!
weldequip

 

[Welderpaul]

Less than legal action resulting in using sh1te copies!
weldequip

Very bad press for Weldability then.

Weldability Chinese made Steve?

 

[weldequip]

I was trying to suss that out looking at the photograph Wozza posted. They don't even look like re-settables to me, just standard none re-set inlines; that badly burnt though it's difficult to place em. Weldability own brand some decent stuff but I'm not familiar with that model mentioned.
Flashback Arrestors have to pass rigourous safety tests (in Germany) & I wouldn't touch any that are not British/European/American made.
weldequip