Hi all, been absent a long time! Sort of lost interest in many hobbies including Paraffin lamps but that interest is peeking out again! Had a quick peruse on eBay for what’s what and boy have prices increased for certain stuff!! Anyway I may be getting back into fettling and maybe some inventing now I have a small workshop again. Some repo Bialaddin fire guards could be forthcoming soon too now I’ve learned to TIG weld! On the inventing theme and Vapourisers in particular, was thinking about reinventing the wheel! My thought was instead of using a 0.2mm jet hole which is a pain to produce how about a larger hole but with the pricker wire extending through it leaving a roughly 0.2mm opening around it? Has anyone tried this? Could the jet be ‘pricked’ by the up and down movement of the wire maybe dislodging carbon from around it instead of piercing through it? Well that’s one new idea and before I spend a day fiddling thought I would ask here for ideas Ta, Steve.
Hi and welcome back Steve @ateallthepies ! As for your idea with the larger holes and using the pricker to reduce I'd be a bit sceptical. Besides there would be no way to clean the orifice properly it may also lead to an oblique fuel jet. And during the larger diameters it could be hard to control/maintain the correct size of the orifice. Mind you that the amount of fuel passing correlates with the 5th power of the orifice size.
Hi Martin, info taken on board but will have to look up the term ‘fifth power of the orifice size’. I think I would worry about keeping the jet clean until seeing if the idea will even work? Drilling a larger say 1mm hole and using a 0.9mm rod or even a 1mm rod reduced down would be magnitudes easier than drilling 0.20mm holes in Steel with those tiny and very brittle Carbide dremel type drill bits! Also as the drilling would be easier the hole depth could be much deeper adding strength and reduced distortion over use maybe? I just won’t know if the gas coming out the jet needs to be through a hole like normal or through a ring shape to work properly....I know how finaky these lamps can be!
Hi Steve, if the bore would be 1mm and you would like a 250CP output the wire dia should be 0.9873mm, giving roughly the same like a 0.16mm bore. If the wire would only be 0.95mm then that would give the same like a 0.31mm bore, which would already give far more than 500CP. The 5th power would mean an exponent of 5. So the if the bore dia is "D" with the bore area "a" it is "a = PI*D²". If you put in a (round) wire with the dia "d" it is "a = PI*(D²-d²)" Then the vapour throughput is proportional to A⁵. I guess that it is difficult to handle the tolerances with the bigger bore and wire diameters.
Thanks Martin for that explanation...Maths was never my strong point but I get the gist. Would never have known the wire diameter would need to be so close to the bore diameter so thanks for giving me a good start point! Will try 1mm hole and 1mm rod and wiggle as necessary!! I can pretty accurately determine drill bit and rod diameters but not the actual diameter of the drilled out hole. Will let you know how it goes.
Oh btw, I’m talking about Bialaddin/Vapalux vap tubes for now. Was of the understanding these are 0.20mm jet hole? Is the 0.16mm for another make of Vap tube.
That is independent from the make or type, it depends only on physics. For paraffin the 0.20mm would correlate with 350-400CP. If petrol is used it's reduced to 300-350CP. I only mentioned the 0.16mm since I was aware of that size for 250CP for paraffin.
Well a 1mm hole and 0.90mm rod doesn’t work ball o flames! Will get some 1mm rod and have another go.
I seriously doubt this will work. One of the things the jet does is expand into a cone of vapour which gathers a great deal of air before entering the mixing dome. For max efficiency that jet needs to be as accurately round as possible and firing centrally into the air space to create the correct fuel/air mixture. It might work if you can centre the wire in the hole but that will require some neat engineering and anyway I am not sure an annular ring of vapour will gather the corect air volume to create the correct mixture. The vapour cone will be wider and to get the mixture right you may have to tinker with the air intakes. So I have doubts but you can make me happy by proving me wrong. ::Neil::
Yep you are probably right. When these lamps were widely in use years ago I suspect lots of methods were tried in the design and what worked well is what we have still today? I do like to tinker so I ordered some 1mm rod last night so I’ll have a go. Never thought to adjust the air intakes tho, thanks for the idea!
Hi Steve, i would say...if you could make a vaporizing tube with a jet hole & pricker combination that's able to shoot out a STRAIGHT stream of liquid fuel (when cold), there could be a fair chance that it might work. Of course, that's only a rough guess with the assumption that the air intake and mixing tube size/ length could match nicely. Also, the vaporizer tube must be of sufficient capacity(sufficient path length) to enable a complete conversion of the liquid fuel into a gaseous state before it leaves the orifice. Otherwise, the Bernoulli effect required for a good fuel-air mixing is just not going to be sufficient.
Correction: its probably still a liquid in the vaporizer, but it has got to be completely gaseous upon exiting the nozzle orifice, regardless of the temperature.
I’ll give it a pump and see how it squirts...I envision it spraying all over the place but we will see! Ta for the advice.
Right...if it ends up spraying all over, you might be able to adjust it till its a straight stream.(that's when cold). That way, you stand a better chance(when hot), for sufficient air-draw from the intake before entering the mixing chamber and in turn create enough turbulence for the mixing before everything reach the burner cap and mantle. Otherwise, you can expect another sooty fireball i guess.
BEWARE Steve. That's neither solid advice nor suggestion. Very risky when the fire's on....only for daredevils. Get ready for anything when its hot! I've got the living daylights almost blown out from me when i tried something similar that..with LPG on some homemade stuffs.
Well that idea didn’t work either. Although there wasn’t flames shooting out the hood like last time the mantle just didn’t want to fire into life and went black. No hissing sound either that I could tell. Seems they got the design right after all he he! Must need the jet of gas/vapour to be a straight squirt up to the top of the mixing dome? I haven’t given up tho, will still be tinkering with vapouriser ideas as they are ridiculously priced if you need a new one!
I would say yes, its best to get the liquid fuel stream straight...during cold test. When its hot, you won't be able to see whether its straight or not. Reason: only a sharp straight jet will create a sufficient low pressure around the air intake. Only this will ensure proper turbulence of the fuel-air mix during its passage in the mixing tube. Almost mandatory. I have tested lighting up when the jet was somewhat skewed or shooting towards the side wall of the j-tube mixing chamber. Result: either the mantle lighted up dimly despite sufficient pressure or it flamed / halo continuously outside the mantle, with a similarly dim light. Sometimes, only burning within the mixing chamber, turning it red hot.
If the jet of fuel is not straight, what you will get is a flame that's similar to an industrial burner for heating. The nozzle for this is basically an atomizer where a conical flow of finely dispersed fuel droplets are being ejected. The principles are different. There's a forced jet of air being introduced into the burner assembly from a blower. You don't want to have this type of workings in the lantern. It does not work that way.
Allright, your best bet: assemble and test your vaporizer/ nozzle complete with the mixing chamber and burner cap assembly without the mantle attached. Not with kerosene or any liquid fuel but with propane/LPG/butane gas regulated to about 2bar or less...similar to that of a domestic stove. If the flame at the outlet of the burner cap is blue, gentle and not turbulent, chances are it basically works. If its a large orange-yellow sooty flame, don't expect it to light up any mantles.
If anything like this could have worked, Fred Tilley would have done it about 100 years ago. Apart from being mathematically unfeasible, the pricker/restrictor wire would very quickly burn out in the jet. How much is a new Tilley or Vapalux vapouriser these days? I can't remember the last time I bought one...
Steve, try inserting a piece of wire through the jet of a domestic stove and light it up. You will know instantly if that idea works at all.
base-camp have the 169's @ £30.50 and the 606 @ £27.95 plus postage. Expensive, especially when one considers the dubious quality, it wouldn't sting so much if they were as good as those from the fifties and earlier when things were made by engineers not accountants. Henry.
£30? - well, I wouldn't like to make one for that (even supposing I could, of course). My spares box alone must be worth a fortune...
@ateallthepies Over in the stove camp, the concept of a larger diameter jet orifice with a reaming inner component that controls the size of the orifice and burner output defines the Borde stove working principle. My repair of a Borde HERE involved the use of a hypodermic syringe needle, a method I devised, with an American colleague’s inspiration and described HERE. Hypo needles can be obtained in a wide variety of bores and a portion of one can be silbrazed into an enlarged jet orifice, restoring it to the original specification. It may be the hypo needle idea could be incorporated in your vapouriser concept. John
There's different 'geography' between the stove and lantern designs. In the Borde stove, not only is the flame at a distance from the point of restriction at the top of the fuel tube but also above it which means heat will be travelling away from the 'pricker' and thus unlikely to melt it or burn it away. In the Tilley or Vapalux arrangement, the proposed 'pricker/restrictor' is just about smack in the middle of the hottest part of the burner and slightly above it, subjecting it to maximum temperatures. In practice, using the pricker to slightly throttle a worn lantern jet and reduce its aperture very quickly results in the end melting or burning away - I guess it's a toss-up which actually happens first but the end result is the same. I've little doubt the same would happen with the proposed new design...
Atealthepies, if you are really determined to make it work somehow, no matter what, then you might want to use a tungsten wire for that. Its a lot more temperature resistant. No guarantees it would not oxidize eventually.
How much is tungsten wire... Edit: https://www.amazon.com/gp/product/B...0c-52fa-b6a2-3a7e68f14188&pf_rd_i=11260366011 About $50 including delivery - how much is that in real money? It must be around, hmmm, let me see... ...the cost of a brand new Tilley vapouriser.
That means if its purely for the sake of saving some money instead of buying a new Tilley vaporizer, then its not worth the trouble. But if its also for the thrill of re-inventing the wheel, then...whatever it takes, whatever it costs...
