Go Back  PPRuNe Forums > PPRuNe Social > Jet Blast
Reload this Page >

Portable butane gas heaters

Jet Blast Topics that don't fit the other forums. Rules of Engagement apply.

Portable butane gas heaters

Reply

Old 11th Jan 2019, 18:45
  #1 (permalink)  
Thread Starter
 
Join Date: Jan 1999
Location: UK
Age: 71
Posts: 467
Portable butane gas heaters

I've got a couple of portable butane gas heaters (1 Parkland, 1 Camping Gaz) which both use 220 g cylinders. When ignited, the flame on both of them diminishes after a few minutes. If switched off and left for a few minutes then re-lit the flame resets to full, then the cycle repeats. Is this a standard characteristic? Is it a problem that can be remedied?

Thanks for info.
Discorde is offline  
Reply With Quote
Old 11th Jan 2019, 19:05
  #2 (permalink)  
 
Join Date: Oct 2002
Location: West Wiltshire, UK
Age: 66
Posts: 369
If they are running at a high output, then the bottles can cool down a lot because of the gas evaporating (latent heat of evaporation and all that) and the cooling can reduce the gas pressure a fair bit. If this is the cause, then you can usually tell by looking at the bottle. If it has condensation, or even frost, on the outside then that's a good indication that the bottle has cooled down a fair bit.

Might be something completely different, but I had something similar years ago when we had a gas hob that ran from a bottle; turn all the rings on and the pressure would drop after a few minutes.
VP959 is online now  
Reply With Quote
Old 11th Jan 2019, 19:31
  #3 (permalink)  
 
Join Date: Jul 2005
Location: Sunderland
Age: 74
Posts: 1
To solve it pour a kettle full of boiling water over the gas bottle and problem solved . You may have to repeat this after an hour or so if outside air temperature drops further.
roofbox is offline  
Reply With Quote
Old 11th Jan 2019, 21:26
  #4 (permalink)  

Avoid imitations
 
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 11,849
I wouldn't go pouring boiling water over the gas bottle because I value my personal well being and safety too much. Warm to hand hot, maybe...
ShyTorque is online now  
Reply With Quote
Old 12th Jan 2019, 08:40
  #5 (permalink)  
Paid...Persona Grata
 
Join Date: Aug 2004
Location: Between BHX and EMA
Age: 73
Posts: 235
220g sounds a bit small for a heater, my space heater runs off a 3.9kg bottle. I guess the cylinders must be operating at full output and what VP said above is right. Can you try them at a lower setting and see if they run satisfactorily?
UniFoxOs is offline  
Reply With Quote
Old 12th Jan 2019, 08:47
  #6 (permalink)  

Avoid imitations
 
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 11,849
A mistake some people have made in the past, having seen ice form on in-use gas bottles, is insulating them, such as by putting them in a sealed, foam filled locker on a caravan. They need to be allowed a circulation of free air so they take the small amount of heat that provides and so don't cool too much.
ShyTorque is online now  
Reply With Quote
Old 12th Jan 2019, 09:12
  #7 (permalink)  
 
Join Date: Nov 2015
Location: Farnham, Surrey
Posts: 1,111
Butane only boils at -1degC, so in cool weather it's barely warm enough to get the gas to boil off anyway. When the act of boiling (or evaporating) chills the liquid that just makes it worse - if the liquid butane gets below -1degC then it is maintained as a liquid (which won't burn) by the temperature alone, whereas above that it needs the pressure to stop it boiling. This is why propane is more popular with caravaners - propane boils at under -40deg, so even when it is chilled by the evaporation it's still well above its boiling point and still delivers a decent gas pressure/flow.

PDR
PDR1 is offline  
Reply With Quote
Old 12th Jan 2019, 11:48
  #8 (permalink)  
 
Join Date: Dec 2015
Location: Cape Town, ZA
Age: 57
Posts: 59
It is extremely difficult (and expensive) to obtain a pure gas, so all the commercial LPG sold is a mixture of propane and butane. In fact butane comprises two isomers, one with a boiling point of -1C, the other -11C. Mixtures are adjusted to their target markets.
GordonR_Cape is offline  
Reply With Quote
Old 12th Jan 2019, 16:12
  #9 (permalink)  
 
Join Date: Apr 2008
Location: on the ground
Posts: 150
The composition of "LPG" is hardly relevant when the device in question uses straight butane.

Nonetheless, automotive LPG in Australia is composed of propane with up to 50% butane permitted (actual butane content obviously depends on the relative market prices of butane and propane, and the composition of the source of the product).

Bottled LPG including BBQ bottles and domestic bottled gas is straight propane with no butane permitted, to avoid technical issues with air/fuel mix in primitive appliances. This is why you are not permitted to fill cylinders with "autogas".

As noted, the boiling points of the isomers of butane are quite high; so drawing butane from a small container relatively quickly, particularly in cooler weather, will result in cooling of the remaining contents and hence a loss of vapor pressure in the container.

A 3.9kg cylinder is certainly propane, with a boiling point at atmospheric pressure of -47degC and a much higher vapor pressure than butane at ambient temperatures. Butane is used where small lightweight containers are required; with disposable lighters being an extreme example.
nonsense is offline  
Reply With Quote
Old 13th Jan 2019, 01:14
  #10 (permalink)  
 
Join Date: Dec 2015
Location: Cape Town, ZA
Age: 57
Posts: 59
Pure n-butane is not suitable for cold weather use, and in many markets a mixture of 10-30% propane is permitted, while still being called a 'butane' cylinder.

The terminology, benefits, and uses are complex, and some graphs of vapour pressure are also helpful to the discussion. I found this article to be a detailed and useful explanation of all aspects of this question: https://bushwalkingnsw.org.au/clubsi...Q_Mixtures.htm
GordonR_Cape is offline  
Reply With Quote
Old 13th Jan 2019, 13:18
  #11 (permalink)  
 
Join Date: Oct 2006
Location: UK
Posts: 4,414
In the 1990s in China the Gas Mains system was still being installed so apartments blocks had large LPG tanks and smaller apartments like mine just had a tank delivered by the local supplier.

They used to deliverer them on a motor cycle with a tank on a pannier either side of the rear wheel.

Didn't half light up the street when they fell off.
Fareastdriver is online now  
Reply With Quote
Old 13th Jan 2019, 13:45
  #12 (permalink)  
 
Join Date: Nov 2000
Location: Cambridge, England
Posts: 3,377
Ah, I've only just(!) realised the timely nature of this thread.

It's all very well filling your #brexit cupboard with rice and beans, but the question I didn't ask myself until a couple of days ago was "how are you going to cook this when the gas and electricity get turned off?".

I see Jet Blast is waaay ahead of me this time
Gertrude the Wombat is online now  
Reply With Quote
Old 13th Jan 2019, 17:27
  #13 (permalink)  
 
Join Date: Feb 2007
Location: Currently within the EU
Posts: 309
Originally Posted by Gertrude the Wombat View Post
Ah, I've only just(!) realised the timely nature of this thread.

It's all very well filling your #brexit cupboard with rice and beans, but the question I didn't ask myself until a couple of days ago was "how are you going to cook this when the gas and electricity get turned off?".

I see Jet Blast is waaay ahead of me this time
Let's not get this out of proportion. The lights aren't going out and you'll still be able to travel. If you've got money and health, Brexit will not be the end of your world.
It's the poor sods on low fixed incomes or none at all who will suffer. And they don't even have a Labour Party looking after their interests.
Sallyann1234 is online now  
Reply With Quote
Old 13th Jan 2019, 17:48
  #14 (permalink)  
 
Join Date: Nov 2000
Location: Cambridge, England
Posts: 3,377
Originally Posted by Sallyann1234 View Post
The lights aren't going out
Well, I would hope that some sort of deal over the French interconnect is being done. As long as it's being sorted out by techies and the politicians don't get involved (probably most of them have never heard of it) we should be OK.
Gertrude the Wombat is online now  
Reply With Quote
Old 13th Jan 2019, 22:01
  #15 (permalink)  
Thread Starter
 
Join Date: Jan 1999
Location: UK
Age: 71
Posts: 467
Doh! Should have worked out the latent heat factor myself (having done a chemistry degree, albeit 50 years ago). Our house is all electric so the mini heater & gas ring are for emergency warmth and cooking in the event of a power outage. Our central heating is gas fired but electrically controlled.

Did a bit of experimenting - restricting flame level to moderate reduced the cylinder cooling effect and also hand-warming the cylinder restored pressure when required. So, warm your hands over the heater, then wrap them round the cylinder!
Discorde is offline  
Reply With Quote

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service