Caravan Gas question for use with special effects

[dj_barber]

Hi,

 

I must first state that this project I am undertaking has been extremely carefully researched, and has the support of various industry professionals, however there is one question I cannot answer without purchasing parts, and was hoping that someone on here will have!

 

I am using a pigtail to run from the propane bottle to my system (those found for use on caravans) which goes from the standard propane bottle fitting to a "W20" nut, and I need to find the diameter of this nut (is it BSP) to get fittingd for it, or find somewhere selling fittings for it to connect it to my system.

 

Any ideas people?

 

Many thanks,

Dan

[Robin D]

Hi Dan.

 

I'm confused as to which end you are referring to. The propane bottle fixing is a 5/8" left-handed thread. However the size is academic as it needs the dome section to mate properly with the bottle so you must use the proper propane connector. There is insufficient detail in your post to help with the other end. I'm concerned that your 'various industry professionals' do not include a Gas-safe engineer amongst them. Although not technically a requirement for LPG, they are still the experts I would turn to for advice.

 

You can buy complete pigtails from most caravan outlets and BES amongst others do a huge range to varoius fittings at the appliance end.

 

Edit: Just reread this. The W20 nut mates with M20 bolts but will not be gas tight. It's designed to mate with a W20 standpipe.

 

Robin

[Jivemaster]

For gas tight pipework it's very likely that you will need to purchase fittings.

[annadeus]

For gas tight connections BSP taper threads are normally used with a ptfe single wrap. If you extract propane directly from the cylinder via a pigtail hose the pressure is very dependant on the temperature of the liquefied propane in the cylinder at 21C. The pressure is approx 90 psi, rising rapidly with temp increase. If the cylinder is tipped over then the hose would deliver liquefied propane. The valve often freezes or jams open from cylinder contaminants. Many burners flare uncontrollably when fed liquid propane. I would recommend a variable pressure regulator directly onto the cylinder and the output of this regulator taken via flexible, in date marked, LPG pipe. The tail on the regulator is often 1/4 BSP female thread. Hi flow cut off valves can be added to stop the gas flow if the pipe is open ended. The system should be pressurised then with cylinder off. Pressure should be retained proving the systems integrity. Do PM me if you want help with safe system design.

[slipstream]

I read this as - you've bought a chinese propane flame system. Whatever the chinese have sent you will either be for their local market or US - either way, no use here - their hoses tend to be pretty sub standard also.

 

Find a local supplier of propane that does installs for fast food caravans, or understands LPG in cars, they can get the tails you need manufactured. You need liquid propane delivered to the heads, most users convert it to gas at the bottle, which is a whole different set of pressures and temperatures.

 

Sam