The outermost part fits together like a glove you could not get a better fit, the inner chamber when inserted into the outer chamber has a large gap around it to hold water I can see this being correct , the seal on the inner chamber peace has a small gap around it if this chamber was full of carbide it would sink push the water up from underneath and threw this gap I think ? But you could not regulate the flow obviously, I have searched and can not find any filling lines atall on either chamber

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If that's the case, then the outer cylinder is a closed system, and the only way any gas or water can get out is through the burning nozzle. Regulation may have been through controlling the flame, or it was so well designed that it self-regulated. The pressure of the gas would cause it to flow to the nozzle at the right rate for a good flame, and also put the whole contraption under a positive internal pressure (there would be air above the water), which would force more water into the carbide chamber as the chemical reaction slowed down, and get the reaction going again. It sounds cyclical, but in practice it would probably run quite smoothly until either the amount of water dropped too low, or the carbide was exhausted. All this would depend on the outer seal being pretty good - it may have been greased or had some other sealant to keep it airtight.

Thankyou ! Very much for all the advice , my premier lamp the seal is a bit cracked is their any website anybody knows of where I can buy replacement seals and spare nozzles from many thanks

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https://www.caving-supplies.co.uk/cgi-bin/psProdSrch.cgi?mode=user&transid=&source=again&search_text=&formCategory=Carbide+Lamp+Spares&formBrand=All&search=Search 

Thanks for all your help much appreciated have made my order

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Hello everyone just wanted to do a small update on the fisma lamp I have got this lamp working now it actually works very well would like to try it one day for not having any regulator for the water I am very surprised by this .

The jet in the photo is the one that I got with this lamp it’s a strange shape family crest type symbol with 3x A inside of it then says 42 litros 1 na

1 tried my bray 390 Neto 10 1/2 litre jet made in England inside this after a much better flame also
No black smoke coming of it

Could I ask what is the black smoke?

I have attached 2 photos of the lamp working I tried to rotate them the correct way very sorry I still can’t get them correct for the Forum though

[photo]120493[/photo]



[photo]120494[/photo]

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It's really good to see it working - fascinating.

The black smoke is carbon, the gas produced is acetylene which is a very dirty gas, unless the gas/air mix ratio is correct you will get lots of black smoke.

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Ahh I see Thankyou very much will be impossible to get it mixed correctly I guess then as no regulators ,I was wondering if this lamp was just meant to be mounted on the walls in the tunnels and not carried around really ? Well that is if it was even meant to be down a mine

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It may be purely down to the jet size. If too much acetylene is coming out, it won't burn very efficiently.

What a good lamp will do is burn bright yellow with minimum soot. Too much gas/not enough air will produce soot. The bright yellow of a flame is incandescent carbon particles - same for a paraffin lamp, candle, or gas lamp. Optimum efficiency for a flame producing light is where there is enough carbon in the flame to glow brightly, but the carbon is largely oxidised to carbon dioxide, hence little soot. A smoky flame shows there is too much acetylene being supplied for the amount or air available, so it produces light and soot. The oxy-acetylene cutting torch provides so much oxygen that all the energy produced provides heat, not light, and no soot. When the oxygen supply to a cutting torch is turned off, the flame immediately turns yellow and smokey.

So to reduce soot in a lamp, perhaps a narrower jet is required, or perhaps these lamps were smokey and this was accepted by those that used them.