Can anyone (well a qualified or knowledgeable person) tell me if the bleeder screw on the gas bottle needs to be done up tight? To me it's a no brainer, however I had a situation the other day and I just want to confirm one way or another.
Situation being...I got a bottle filled the other day (establishment will be named if it's proven their practice was negligent), paid $45 for it, and after I connected it i came back out and it was pouring out gas from the bleeder screw. I didn't know what was happening so I got him to come over (lucky I was staying there also). He tightened the bleeder screw and I asked for it to be refilled. His solution to me was to get it filled at the next town I got to and he surmised it hadn't lost much. I weighed the bottle and thought it was at least 2kg down. So the next morning I asserted I wanted the bottle refilled and they begrudgingly did it. Turned out it was 3kg. I stopped up the road and could smell gas.....and unbelievably the bleeder screw wasn't tight....but nor was the other bottle filled elsewhere.
So does it have to be left open or are they just playing silly buggers? I've tightened both up and had no ill effect....probably just get extra time out of my bottles I'm suspectin.
The purpose of the screw is to allow air to escape when filling with gas in liquid state - It is NOT a relief valve. It should be firmly screwed in when bottle has been refilled - note as it is freezing cold when gas reaches the level of the screw, it should be initially nipped up, then rechecked several moments later due to cold gas no longer creating a shrink fit on plug.
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Possum; AKA:- Ali El-Aziz Mohamed Gundawiathan
Sent from my imperial66 typewriter using carrier pigeon, message sticks and smoke signals.
I no expert and some person who is should be taken over my opinion.
But the screw should be done up firmly after the fill and should not leak any gas at any normal time. I cannot understand any fill person not doing it correctly as the procedure is simple. But saying that I have seen plenty that are not competent and are a danger to all.
How many do you see not wearing gloves as called for, to protect from the freezing gas blast if they have to go near it to shut it down or even shut the bleed screw. I once offered a person my gloves to use but they said "there are some inside, thanks"
Jaahn
-- Edited by Jaahn on Friday 8th of September 2017 12:10:20 PM
Thanks guys.
Yes I suspected it was incompetence the first time and nastiness the second.
Lesson learnt to recheck them after every fill. I've had it happen before recently, so there's obviously so many clowns out there filling them. It's kind of irritating when there's such a hoo har made these days about qualified, inducted people filling them. I reckon prior to those rules there was never a problem (30 odd years ago).
hi
Yes massive incompetence
When is it full ,when u get solid liquid coming out .
When the bottle is being filled there is turbulence inside causing random liquid sputtering .
If they donot believe u , weigh the bottle with your own digital scales !!!!
Hako that makes sense mate as how would air get in there to start with if the tap is shut , what pressurises the liquid to come out if all the gas is forced out the cylinder initially on fill ? Prior to filling there must be a vacuum in the cylinder ??? otherwise what replaces the liquid coming out.
Hi all just done a bit of reading found an article on refilling gas cylinders might make light reading, not sure if I have attached it right , see how it goes
There is no air in a gas cylinder fellas - only gas and liquid. When the bleed screw is open it is releasing gas.
Good Luck.
Correct hako there should be no air in there ! When the gas "runs out" and you change it over there is still some gas in there so shut the valve properly.
But it is possible there MAY be some air if the valve is left open. That is not normal or recommended as it may result in dirt or rubbish getting in too or even water BAD !
The gas/liquid relationship of LPG and other similar stuff like refrigerants is a bit complex and hard to understand but very useful for fridges and a/c units and LPG. However the temperature is very important so keep 'em cool and out of the sun to avoid blowing the relief valve and venting some gas.
Cheers Jaahn
-- Edited by Jaahn on Sunday 10th of September 2017 10:06:21 AM
Doesn't matter. Gas or air ! It's to purge contents to let it fill with Liquide gas.. As it's a pressurised vessel .. Unlike a glass when you fill with water the air in it is purged as it's filled . As soon as liquid comes out bleeder .. The cylinder is full . Turn off tap and bleeder valve . Disconnect Done .
Having filled a few hundred or so gas bottles I can say the bleed screw must be nipped up on completion of filling, and completion of filling is when the scales tip or a liquid begins to emit from the screw. There is a sequence which should be followed to safely shut down the operation and many fail to do it correctly, it is mainly so that when you uncouple the hose you don't get any blow back, I still have my extra long screw driver for just such a job.....
The liquid is decanted into the bottle from another bottle/vessel, this liquid displaces the gas in the empty bottle which has very little presssure remaining, there is no vacuum required just higher pressure of a compressed gas (liquid).
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Checking out the places I drove past a thousand times................
BAD !
but very useful for fridges and a/c units and LPG. However the temperature is very important so keep 'em cool and out of the sun to avoid blowing the relief valve and venting some gas. 
