The glass is from a candle lantern, brass support bracket something I made. Cap yet to construct. John
Hi John, that looks really cool! ...The brass flame nozzle thing looks really well made! [i suppose it would do being German ] What sort of era/age is this lovely lantern from?.. Any particular specific usage? It's not a company i have heard of before?
Ah, that’s the burner and it’s of British manufacture, company, George Bray & Company, Leeds. They made a great variety of burners for town gas (including street lamps) and acetylene lights for the home, bicycles and motor vehicles. I’ve one of their ‘Elta’ burners, unused. Similar to the ‘Luta’ but for those basket shapes on the burner jets, made out of stearite, a form of soapstone. If the water drip rate is reduced in an acetylene lamp gas generated reduces and the light dims. Most burners, including the Luta, can’t cope with that and get caked - possibly even blocked - with carbon. The Elta’s jet construction enabled it to work at low light levels without producing carbon. Neither have I encountered the lamp manufacturer’s products before, but Neheim is the town where they were based evidently. When made? 1930’s I would guess, probably for the mining industry, surface working and below ground where no flammable/explosive gas was present. Lamp now with cap.
Indeed David, a safety device common to most acetylene burners. There’s a taper too on the threaded riser into which it screws. It creates a gas-tight seal but has minimal mechanical strength as a joint. If the jet blocks, the resulting build up of pressure in the acetylene gas chamber is sufficient to eject the jet prior to the acetylene gas exploding. It’s not something I intend to try! - so I ensure jets are clean and aren’t run at low levels (the aforementioned carbon deposition and potential to block). The little carbide lamp is well up to the light output of my ‘pork pie’ Tilley, with the Dietz Vesta merely sipping paraffin but putting on a good show.
This carbide lamp is certainly quite different from most others I've seen. I like acetylene lamps. No other common combustible gasses burning with a controlled manner in free air would produce the level of luminous intensity as acetylene.
Swapped burner on the carbide lamp from the twin-jet Bray Luta to a single jet type of unknown manufacture.
Not God, but one of His favoured ones on Earth - Lighting Division - (@Henry Plews) at a Newark meet one year gave me the Bray Luta burner together with the acetylene lamp it was installed on. John
@presscall That's giving a good light, I'm pleased that you've managed to make some use of the bits and pieces. @plantpot @podbros, the lamp was with a heap of Tilley and Bialaddin lamps/lanterns offered as one lot at auction. Not really my thing even if it had been in good condition, it was in a sorry state and in need of some repair, nevertheless, I was reluctant to throw it away and it languished in the darkest recesses of my shed for many a long year. Long story short, I'd seen some of John's acetylene lamps helping to light the field at a Newark meet and thought he may be able to do something with it. Above is the result. Even though it was of no interest to me, I'm glad I kept hold of it until I found someone who would appreciate it.
Hi John. How is the Neheim vessel pressurised? Is it by hand-pumping? I'm interested in knowing how the acetylene flame changes according to gas pressure. If the flow of acetylene increases then I presume that a greater volume of oxygen is drawn into the combustion and the result is a hotter flame? How does the light emission spectrum change?
No, water (drip, not a trickle) falls from the upper (water) reservoir onto the calcium carbide in the lower container. Acetylene gas is generated and since the only outlet for it is the fine jet orifice of the burner, a moderate pressure develops and is maintained in the space above the calcium carbide. A jet stream of pressurised acetylene emerges from the burner and that burns with the characteristic intense white light. Gas pressure is kept moderate and constant by regulating the water drip to maintain the flame at an appropriate level. Too low and carbon forms at the jet outlet. Too high, and since acetylene is an unstable gas capable of exploding if too self-pressurised, the safety feature of the tapered burner threads hopefully operates and the burner is ejected, releasing the pressure. Clearly, it’s good practice not to reach that point!
Thanks for the quick reply. So it's the same principle as a miner's lamp or cycle lamp? For an acetylene flame burning in the atmosphere, with no additional oxygen, how much does the flame vary in intensity and colour temperature? Does the type of burner affect this? Do you know whether anyone has measured the spectral power distribution of the emitted light to quantify how much it varies?
Just the same, yes. The flame doesn’t vary in intensity or ‘colour’, at least not to the eye. Initially, as the air above the calcium carbide is expelled by the acetylene generated there’s a blue element to the flame, but this soon disappears, not shown here, which was taken some minutes into the firing.
@Lindsay It seems that the colour temperature of a naturally-aspirated acetylene flame, typical of many such carbide lamps was found to be around 2360K. That's when burning properly at their 'brightest' or most intensely luminuous. The flame colour of such flames are in general, significantly 'whiter' than what a candle or wick-type lamp would produce. Yes, the subject on the energy distribution in the visible spectrum of the acetylene flame had been studied and researched into considerable detail more than a century ago. You might be interested in this one:-
