Losing gas am in Bugsworth any contacts

[onionbargee]

My welding gasses are 280 bar pressure and use the same connection, that kind of proves there's nothing wrong with the metal to metal contact seal.

[DeanS]

there is a chemical added into the gas...so you can smell it..(safety), but the chemical is heavier than the gas so it drops to the bottom of the bottle, so when you get close to the end of the bottle, the smell will get a lot stronger, than in a full bottle. ...but with everything off, the smell should be contained in the bottle....diluted washing up liquid on the joints as mentioned....to see if a leak forms any bubbles....

[MtB]

It is Mike, if the actual seal is leaking.

Belt & Braces etc.

M

 

 

Ok as you insist.

 

As Mango points out, gas leaking past the cone connector still escapes via the 1/2" diameter hole in the middle of the brass nut if the thread is sealed with PTFE.

 

How does PTFE on the nut thread stop this path of escape?

Thanks, Mike. There had to be a reason they weren't fitted more widely, apart from costing a few quid more, that is. So why can't we have nitrile seals on the one with nuts?

 

Nitrile seals are less reliable. When tightened with a spanner some judgement is needed as to how tight the nut should be or the seal gets over-squashed and splits. And the wear our anyway with repeated dismantling of the joint.

 

As others have pointed out the Pol connector is actually pretty good when assembled correctly. The male part is terribly susceptible to casual damage on the cone though, so needs treating with great care.

[MtB]

there is a chemical added into the gas...so you can smell it..(safety), but the chemical is heavier than the gas so it drops to the bottom of the bottle, so when you get close to the end of the bottle, the smell will get a lot stronger, than in a full bottle. ...but with everything off, the smell should be contained in the bottle....diluted washing up liquid on the joints as mentioned....to see if a leak forms any bubbles....

 

Interestingly, people often report they know when their gas bottles are getting low because they can smell the stronger, more concentrated 'stenching agent' inside the boat. This could illustrate they have a tiny gas leak, too small to have been revealed on their last BSS.

 

But more likely this is caused by the fact that when you turn a gas burner OFF not all the gas gets burned. Unburned gas remains inside the ducts and tubes beyond the ON/OFF control and slowly drifts out into the room atmosphere in the minutes and hours after turning the hob burner (for example) OFF. This is the 'gas smell' people pick up on in my opinion.

 

 

MtB

[mango]

 

Interestingly, people often report they know when their gas bottles are getting low because they can smell the stronger, more concentrated 'stenching agent' inside the boat. This could illustrate they have a tiny gas leak, too small to have been revealed on their last BSS.

 

But more likely this is caused by the fact that when you turn a gas burner OFF not all the gas gets burned. Unburned gas remains inside the ducts and tubes beyond the ON/OFF control and slowly drifts out into the room atmosphere in the minutes and hours after turning the hob burner (for example) OFF. This is the 'gas smell' people pick up on in my opinion.

 

 

MtB

There is no doubt that the smell can be stronger when a bottle in nearly empty. The smell is a mercaptan, probably mainly ethyl mercaptan, which has a boiling point of 35^oC, so may be present as a liquid at the base of the cylinder.

[MtB]

There is no doubt that the smell can be stronger when a bottle in nearly empty. The smell is a mercaptan, probably mainly ethyl mercaptan, which has a boiling point of 35^oC, so may be present as a liquid at the base of the cylinder.

 

Interesting. On my recent LPG ACS renewal exams the trainer told us specifically it is not ethyl mercaptan. Ethyl mercaptan is added to methane (natural gas) but something else is added to LPG, which is why it smells so different.

 

He couldn't tell us what it was though! Do you know perhaps? And is the same stuff added to both butane and propane? I've never sniffed them consecutively to see if they smell different from each other.

[MisterDave]

 

Interesting. On my recent LPG ACS renewal exams the trainer told us specifically it is not ethyl mercaptan. Ethyl mercaptan is added to methane (natural gas) but something else is added to LPG, which is why it smells so different.

 

He couldn't tell us what it was though! Do you know perhaps? And is the same stuff added to both butane and propane? I've never sniffed them consecutively to see if they smell different from each other.

Probably Diethyl Sulphide or Tetrahydrothiophene, couldn't tell you which but apparently those are the second and third most popular stenching agents after Ethyl Mercaptan

[mango]

 

Interesting. On my recent LPG ACS renewal exams the trainer told us specifically it is not ethyl mercaptan. Ethyl mercaptan is added to methane (natural gas) but something else is added to LPG, which is why it smells so different.

 

He couldn't tell us what it was though! Do you know perhaps? And is the same stuff added to both butane and propane? I've never sniffed them consecutively to see if they smell different from each other.

According to the safety data sheet for Calor propane "A small quantity (typically <50ppm) of ethyl mercaptan or similar odorizing agent is commonly added to assist in leak detection" https://www.calor.co.uk/media/wysiwyg/PDF/propane_safety_data_sheet.pdf

 

The safety data sheet for Calor butane says the same. The link on the Calor site does not work but I found it elsewhere. http://www.dixonsgas.co.uk/images/products/450-file-1418397467.pdf

[blackrose]

I think washing up liquid is frowned on cos it may cause corrosion.....but in a emergency it's better than a bang IMHO!..... You could always wash the pipe afterwards with plain water

 

Cheers

 

Gareth

 

Yes, testing with diluted washing up liquid is better than a gas leak, but no boat with a gas system should be without some of this stuff. There are a couple of different products available at screwfix. Anything in a pressurised aerosol can needs to be at room temperature before it can be used so don't store it in the gas locker.

 

http://www.screwfix.com/p/leak-detection-spray-400ml/41019

 

http://www.screwfix.com/p/gas-leak-detector-spray-250ml/95781

Edited May 9, 2015 by blackrose

[mango]

 

Interesting. On my recent LPG ACS renewal exams the trainer told us specifically it is not ethyl mercaptan. Ethyl mercaptan is added to methane (natural gas) but something else is added to LPG, which is why it smells so different.

 

He couldn't tell us what it was though! Do you know perhaps? And is the same stuff added to both butane and propane? I've never sniffed them consecutively to see if they smell different from each other.

"The current odorant employed by GTs in the United Kingdom (UK), for Natural Gas is odorant NB, a blend of t-butyl mercaptan (TBM) and dimethyl sulphide and for LPG is ethyl mercaptan tetrahydrothiophene (THT). "

 

This is taken from an undated document, so I don't know if it is still current. https://www.igem.org.uk/media/214303/Pages%20from%20IGEM-SR-16%20Edition%202.pdf

[mango]

I think washing up liquid is frowned on cos it may cause corrosion.....but in a emergency it's better than a bang IMHO!..... You could always wash the pipe afterwards with plain water

 

Cheers

 

Gareth

The problem is that virtually everyone uses far too much washing up liquid when testing for leaks. You need very little.

[b0atman]

No smell in locker this morning but as Dean says proof is in the pudding when bottle is nearly empty and smell is stronger .

I like MTB theory on the gas in the pipes its a good indicator that your getting low on gas.

[David Mack]

I think Ethel Mercaptan was a 1930s American film starlet.

[MtB]

D:

 

I've not seen any of his films though...

[Timleech]

Regarding soft seals for propane regulators, I once had one which had the conventional brass cone, but with an 0-ring set into a groove at the mid-point of the cone.

Worked really well, but the problem with any sort of soft seal is that it's much more vulnerable to damage than the plain metal.

 

Tim

[BruceinSanity]

Thanks, guys, this is a really interesting thread. I shall endeavour to improve my connection technique.

 

There's a gag in there about having room for improvement after 40 years sporadic practice, but I'll spare you that.