My New Toy

Ive bought myself a little 5" Turbine Driven Loco, quite an interesting little thing. It needed a lot of TLC, most of which is now complete but the one thing im struggling with is the gas burner. I've no knowledge of gas systems, this one has two nozzles (to fire the generator) a pipe and thats it. My question is what else do i need? Obviously a storage system but do I need a blowback valve or something like that? I take it also a regulator would be a good idea. Does anyone know where i can get this sort of equipment? What sort of gas is it likely to run off, my guess was LPG?

Thanks Guys

Dave

 

All 32mm gauge normally burn butane (the stuff that you find in cig lighters). Do a google search normally comes up with the answers.

 

Any photos it sounds intreauging

 

Tried google already, not much came up. But at least I know im dealing more with liquids than pressurised gases now.

 

Based on my experince with LPG as a fuel source for a foundry I suggest a pressure regulator capable of going from 0-3bars. The regulators for cookers and BBQ's only run at 0.3bar and do not give enough flow to sustain a decent flame. Mine came from a welding set. For propane reulators try the Sievert blow torch range, available at good tool stores.

Security in the form of blowback protection is always wise in any system.

One item to watch out for at the higher flow rates is freezing of the equipment. The quicker you vaporise the LPG the greater the cooling effect and quite stragely this leads to icing of the valve and regulator. More pronounced with smaller gas cylinders. Size of cylinder depends on the space available and the depth of your wallet. Small capacity cylinders cost significantly more.

This is from my own experiments, it is up to you to make sure you are working safely.

 

Well, yes and no. I'm not sure on the behaviour of LPG, but the systems used on the garden railway locos does actually use pressurised gas (actually similar to that outlined by Adrian above). The complication comes that when gas is pressurised, it inherently cools and liquifies. This is why 16mm-ers (and other folk) hold the gas can upside down when filling their tanks, to push the liquid into the loco tank.

Once the loco tank is full, gaseous butane is tapped off from the top above the level of the liquid gas. As this supply is expended, and the tank naturally heats up, the liquid 'boils' to produce more gas, and so on until the liquid is fully expended and the system returns to atmospheric pressure. Some engines require a warm water bath to keep gas production high enough to sustain the demand, mainly required if the gas tank is so far away from the boiler, and if the ambient temperature is so low, that it doesn't happen naturally. Also, as Adrian mentions, high flow rates can also cause lack of gas boiling to supply the required demand.

http://www.roundhouse-eng.com/tech.htm#gas explains a little more about it.

Now, your 5" model may be butane fired, in which case the firing system may be as simple as above and outlined in the Roundhouse article, or paraffin or other such oil-based fuel, in which case we do start dealing with pressurised liquids and possibly atomisers too. A selection of pictures showing the model, it's firebox area, and the existing bits of the fuel system would be greatly appreciated and would enable a much better answer to be given.

Cheers,

Dom Greenop
DMR