Gas question.

[jimbo84]

Yes I feel stupid.

I’ve had a gas leak on my propane regulator which this morning ignited (first I knew of the leak). A 3 inch flame from the outlet on the regulator. Turned off at the cylinder and flame blown out. No harm done, thankfully. The cylinder is for a blowtorch.

My question is, I have some hawk white jointing compound, is this ok for the thread on the outlet of the regulator? It says on the tin it’s suitable for gas up to 5bar (regulator is adjustable up to 4bar). Is this the correct application for jointing compound though?

I thought all gas threads were tapered but today I learnt they weren’t.

No need to ask me if I’ll be doing a soapy water test on everything in future.

The leak was from the arrow. Where the brass hose fitting screws into the reg.

 

[angellonewolf]

could you get a gas aresster to stop the flame gojng back in the bottle if the worst happens again ?

 

[Dcal]

I'd put a flashback arrestor on it (where you have the arrow) and change the jubilee clips to proper crimp clips.

You shouldn't need a compound on any of the fittings there is something wrong if you do.

Fix the problem you have eg -
fittings not tight,
fittings damaged or scratched
missing O ring or washer.
.......................

Don't try to resolve the issue with gloop.

 

[voipio]

The input side of the regulator has a similar "look" to the mating face and may possibly have the same thread. The part screwed into it may be a taper thread, in which case the seal is via the thread, and there will either be some thread sealing compound or PTFE tape. If that is a parallel thread, then the seal should be via a washer, or similar, at the bottom of the threaded part. The regulator output side adapter has been screwed tight but not made a good seal. Unscrew it to determine where the sealing surface should be, and check to see if the internal thread is tapered or not (use an inside caliper or similar to verify). As Dcal suggested, there may be a missing part.

 

[jimbo84]

Thanks for the responses.

I thought flashback were only needed when using with oxygen?

Measured the thread, the male brass fitting appears to be tapered, measures 2.7mm to 3.2mm. Female outlet on the reg appears to be parallel. There is nowhere for an o-ring to sit in the regulator.

The brass fitting can be screwed by hand right up to the hexagonal part and then nipped with a spanner. It doesn't feel loose in the reg though (feels like the correct thread).

Edit:the brass hose fitting came with the regulator in the box.

 

[angellonewolf]

would have thought any gas thats not inert gas for your own safety is a better idea and thing that burns could go back in to the bottle


im not in the know but @Parm might be able to help

 

[Parm]

Ive never seen a regulator like that with crimped edges.

Find out if the reg is made by a reputable manufacturer and supplied by a known supplier.

I suspect it may be a Chinese special.

My advice would be to put it in the bin and get a new one of known origin and quality.

As far as im aware ive never seen jointing compounds and tapes etc being used on regulator fittings.

Not worth messing about with things going wrong for the price of a regulator.

Also never seen flash back arrestors on gas bottles that just power a blow torch

 

[brightspark]

your not going to get a flashback on the propane bottle unless your using oxygen as well .even if you take the reg off and light the gas it will only burn when it gets oxygen to feed the flame not back in the bottle . nothing wrong with putting a bit of paste or gas ptfe on the threads and then test for leaks before use

 

[Paul.]

Find out if the reg is made by a reputable manufacturer and supplied by a known supplier.

Continental are probably the largest supplier of lpg fittings and regs in the uk, based in Norwich, very reputable company, I've done work for them indirectly.

 

[Parm]

Continental are probably the largest supplier of lpg fittings and regs in the uk, based in Norwich, very reputable company, I've done work for them indirectly.

Ok, I didn't know that, but useful to know.

 

[waddycall]

As brightspark said wack some ptfe or jointing compound on it and wind it back in. Check with soapy water. Job done.
And that’s not a bodge.

 

[fixerupper]

A question ...it looks like there are three tapings on that regulator one in one out what is the third one for ?...

 

[brightspark]

pressure gauge ???

 

[Dcal]

As brightspark said wack some ptfe or jointing compound on it and wind it back in. Check with soapy water. Job done.
And that’s not a bodge.

Fair enough but I'm not sure that the fitting is correct.
The hose clips however "are" a bodge.

your not going to get a flashback on the propane bottle unless your using oxygen as well .even if you take the reg off and light the gas it will only burn when it gets oxygen to feed the flame not back in the bottle

If you are able to turn off the bottle while it's still flaming fine, but if the person using it panics and legs it the flash back will turn it off for you.
When it all goes to rats and the hoses are burning away merrily, it's nice to know that there is another line of defense.

 

[brightspark]

.if the reg was on fire a flashback arrestor wouldn't be any good and wouldn't stop it. they are fitted after the reg they stop burn backs in the hose

 

[Dcal]

I accept that, but it will stop it getting to the regulator.
If the bottle is on fire it's time leg it.

 

[ChrisW8]

Didn’t Challenger have that problem ?

 

[jimbo84]

Thanks for everyones input. I’ve been and got some PTFE tape suitable for gas so I’ll refit it with that and do a soapy water check on all the fittings.

Found the box for the regulator and it appears to be made in India, not sure if that’s good or bad. Bought from the local bottle gas suppliers, who also suplied the hose and jubilee clips.

The bottom of the reg is stamped in, out and the middle one is stamped gauge.

Managed to avoid any panic and although it was a bit of a surprise to see flames coming from the reg aswell as the torch. Lesson learnt on this one.

 

[waddycall]

Jubilee clips are ok on portable stuff. I checked this with gassafe when asked to check a gas fired beacon.

 

[Richard.]

You do not need a flash back arrest on a propane only system.
Worm drive hose clips are not suitable for flammable gases and tbh are crap even on inert gas systems.
Ptfe tape is not ok on bull nose to seat type sealing as it defeats the object of the seat doing the sealing but on tapered threads that’s exactly what it’s designed for so as suggested put some on and see how it goes.