Tilley and similar designs - Vapouriser failures

Good Evening all.
I hope the title is self explanatory - there are quite a few threads around the forum which describe this issue. Please may I open a discussion on the subject to try to get to the bottom of it?

There is no doubt that it happens, here are some threads which have gone before.

Tilley vapourizers burst often in kerosene operation??

Tilley Vapouriser Failure

Bialaddin 320 disaster

I am not sure that any of these really got to the base of the issue (credit of course to all contributors - please add more comments here)

We know some things about bad lamp behaviour with these types - bad fuel, pressure, enlarged jets and bad mantles -but I don't think these can cause a vapouriser to fail by swelling or becoming "pregnant". Some are related perhaps, vapouriser is already worn out, but I don't see them as a root cause to swelling up and failure.

I have posted in various places my dear old (grr!) X246B dated 1164. Yes I know they are reckoned to be LOD PARC (anag) but they must have worked sometimes - for a while at least. Mine has consumed very many parts, much more than it originally cost to buy - so how come? Tank &valve were clean and OK. But vapourisers are not cheap - and it would eat them up in not so many hours.

Did I fit bad parts - I don't think so - all good sources. Or is it more subtle than that? I begin to think it is.

First is the cleaning rod. That can be too long as it comes supplied new. If you assemble it to the control cock and it is tight at the pricking position (overall length is too long and it it pressing hard against the jet orifice when needle is in up position) when it is hot it will punch through the jet. I had one do that in a Cornish field - uncontrollable flames & scrap. A temporary rescue was possible by some peening - but long term that vapouriser was scrap.

So on next attempt the cleaning rod was very carefully fitted by filing to length, just right. This one worked for quite a long while (24hrs burn in several sessions) then it dimmed and was obviously in trouble. Here we go again.... Swollen and stuck in spigot. I have still not managed to remove it - bah - more scrap- but why? Plenty of carbon build up in the tube - after only 24hrs elapsed running - strange? Could it be the fuel - I discount that - it was not diesel?

Lately (see the posts under Worried about CPL!) I changed the burner and vapouriser / mantle together. What a transformation! It is brighter than it has ever been but so far I can't say much so far except it has done 4-5hours burning faultlessly.

I knew my old burner had an issue with the internal ridge which contacts the upper rim of the vapouriser - that won't matter I thought. Not so sure now. Before the vent and glass position were determined by the fact they were sitting on the external cage. Now they come to rest on the vapouriser and gap to the cage rim is some few mm below. The handle pegs can only just slot back in to lock it down. That is different to before.

I reckon vapouriser swelling and bursting is more about running much too hot due to lack of conduction cooling of the vapouriser to the burner body. Old Tilleys and the like sat the burner directly on the vapouriser. Other later designs make that contact doubtful depending on how the parts are assembled.

A much too hot vapouriser will mean weakened strength of the side wall tubing and also more likely that fuel will crack to carbon before it vapourises and burns. I think this could explain much of what is observed.

I need more running time to know.

 

Very interesting article. It’s got me thinking ....
Well written JonD

 

Thank you Pete - it's bugging me - can you tell?

I'm looking at the beautiful unfired Tilley X246B- 500 which has just turned up.
https://classicpressurelamps.com/threads/unfired-tilley-stormlamp-x246b-500-offers.11624/

That spigot looks different to me.. I'm wondering.

 

Well spotted, it certainly does seem longer. Thoughts?

 

Yes, the spigot is longer to support a larger mantle. Unfortunately, the only way the 606 vapouriser can fill it properly is with increased tank pressure which isn't the strong point with post-'64 Tilleys. Did Tilley eventually produce a 500cp vapouriser for these?

I did have a longer spigot machined up and fitted a 500cp mantle but it was unconvincing. The mantle didn't incandescence fully with grey areas on the surface. Extra pumping brought no benefit...

 

I have read the posts on that David and I agree with you. I don't like running X246 tanks at that sort of pressure.
The long spigot interests me not so much because it enables a larger mantle to be fitted but more because it might work as a heat shield to the vapouriser side walls.

Since I think these might be swelling due to running hot that extra length would take direct flame heat which would otherwise be on the vapouriser itself. The heat will go up to the
burner body which is cooled by the incoming air for combustion and some radiation. It should do no harm there.

Now we come to the idea that the early burners are superior to the shrunken ones which appeared in X246Bs. What will be better about the bigger burner? Much larger surface area
and cooler running as a result. I have an idea that my X246B is happier with it's new burner because it is definitely sitting in contact with the vaporiser without a gap so there is a good
heat conduction path up to the burner. The new burner (a JulianDS one) is larger than the original and so will run cooler by the above argument. It is working like magic.

Lastly I am thinking what about a spigot the length of the -500 version but with two grooves? A choice of mantles could be fitted then. Upper groove for standard ~300CP (cough)
the bottom groove would allow a larger one for a bit more CP - whatever that is. It would be even better for cool running of the vapouriser at standard output. It only needs to be hot
enough to work after all...

One other thing I am interested to look at for the high power version. A -500 vapouriser, if it existed, would deliver more fuel vapour but where would the extra air come from?
It would need larger dia intake tubes wouldn't it? Or is the higher tank pressure meant to speed the fuel vapour stream past the same air tubes and so draw in sufficient air.
I suppose that was the theory.

In the main I hope this thread will keep with what makes vaporisers get pregnant.

In the case of my Nov64 X246B I think it might have been OK had I not had an adverse occurrence with the spigot and a drill trying to ream out crud. The drill dug in and what
came out was brass filings (*). I took it all apart, the threads seemed OK so no harm done I thought. Big mistake. In hindsight I think I ruined the surface which should make contact with
the vapouriser. I reckon that is where the pregnancy troubles started.

(*) And a further admission - it was a standard HSS drill. OK I was being lazy. Standard drills are not OK to use on brass because the attack angle is wrong. But I was only trying to ream out some
crud your honour... Brass drill bits have flat faces or they dig in, chatter, and create chips and a lousy surface. Believe me this works even if you are only tinkering with a drill bit in your hand doing some
mild cleaning out - lesson - avoid.

 

There is no doubt that more pressure makes more light. At least up to a point. The US military did some tests on Coleman lamps and whilst I can't remember the detail they showed a considerable increase up to about twice normal but much above that and the burn goes pear shaped and the light drops off again. I am not sure that the increase is linear but you might expect a 20% to 50% increase with a 50% pressure hike. Since there was no apparent change in the air tubes I don't believe Tilley made a special 500 vaporiser. I suspect it was a standard 606 and just labelled as a 500. ::Neil::

 

I take your point, Neil, about these being X246B '500 series' lanterns and nowhere are they claimed to put out 500cp. As you've said in another thread, this is no more than a marketing ploy which, I suspect, was intended to deceive folk into thinking they're going to get 500cp - what else would you expect from a 300cp lantern which is fitted with a larger mantle and intended to run at a higher pressure, especially when there's a big '500' emblazoned on the box - bah!

Anyway, my initial 'gut-feeling' was that these swollen / split vapourisers was a result of fuel quality issues and I'm still very much of that mind, having seen nothing convincing either way. I might add that I now think that vapouriser temperatures may also be a contributory factor but in the reverse way to Jon's line of thought i.e. lower temperatures lead to the accumulation of carbon. This would mean that it is better to maintain full tank pressure by frequent pumping rather than pumping at the start and then letting the lantern burn with decreasing tank pressure until brightness drops to the point that the lantern is crying out to be pumped up. That satisfies my sense of scientific logic anyway...

 

Two good views here, pondering .........

 

I want a thermocouple that can handle the temperatures involved now .
I have one good to 475C but I think going anywhere near the vapouriser would fry it. The wire insulation wouldn't take it.

It might be interesting to measure at the knurled base out of the main heat but it is not the temperature there I want to know. Obviously any infra red methods are out because of radiation
coming from the mantle - it more or less totally masks the spigot.

Maybe some research into different thermocuples is needed. There is nothing to lose.

 

I had been looking for this old thread too - I think it contains more useful info on the problem. It was a magnificent effort but I suspect overheating was the issue here.
Stuman Vapouriser conversion

Then @Tony Press reported good success with a Korean made version.
Korean Tilley Vapourisers

That one has a very flat end and would make contact with the burner over a reasonable area. If instead they had machined the spanner flats away from the hot end that design could be near perfect?

 

I have been looking through the pile of dead Tilley vapourisers, all eaten by my X246B over the last few years.
It has turned up some things to think about.

Here is the original vapouriser that came fitted in it - I assume this one is from 1164 like the rest of the lamp.
Notice the flat rim around the edge, it has a few nicks and gouges now - that was done by me while peening the opening smaller. Originally it was smooth.



I bought a replacement from Tilley - recent production. It dispatched that one too, This one has what appears to be a welded end. It also has what appears to be a narrow ridge around the edge.



It has also eaten this one - might be a Dunmurray one - hard to say for certain. Again note the rounded shoulder but no ridge.



and another, this one has some shoulder part of the way round at least.





I think the best one is the 1964(?) one. It also has a brass thread at the fuel cock end while the rest are steel.
I suspect the flat shoulder was meant to mate well with a rim of some sort at the top of the spigot for efficient heat transfer. Does anyone have a spigot to check for a shoulder? There doesn't seem to be one in the burner itself.

Possibly I wrecked that shoulder with my misguided cleaning attempt and none of the vapourisers stood a chance of staying cool after that. I think they softened and that is why they bulged.
In one the pricker punched through - that could be setup of pricker length but softening by overheating won't have helped.

The rounded tops of the other vapourisers I regard with suspicion. It might be they would have worked with a good burner then again I have my doubts. If there is a shoulder for them to contact I think I would try to make them as flat as possible around the rim before use. Certainly I would remove any burrs/ridges.

The new one I have fitted to the X246B today, along with a new burner assembly, was another from Dunmurray. I don't have pictures of it but did seem pretty well shouldered and flat.

I hope these have not died in vain and it is useful to someone.

 

The top rim of the vapouriser is in contact with a shoulder within the burner tube. This means that in lamps and lanterns which don't have a globe cage supported on the tank, the weight of the burner, hood and globe is taken by the vapouriser. I don't think it's actually anything to do with heat transfer; purely a matter of simple mechanics. It's also another reason not to use home-made brass vapourisers - that metal isn't hard or strong enough to bear the weight, particularly in a high temperature environment where the contact area is small so pressure is high.

The brass shoulder in contact with a steel vapouriser will wear over the years and regress into the burner. It follows that the position of the jet in relation to the three air tubes will alter thus the venturi effect will change and as a consequence, so will the mixture. Maybe that's a factor...

 

Thank you David! You confirm what I had always thought, that there is a shoulder.
There has to be or as you say the self supporting type without a cage would be in trouble.

What is bothering me is that in my old burner I don't see one, or more accurately, I don't see the remains of where it would have been before I accidentally destroyed it.

That is why I questioned whether it was actually part of the spigot. That might make some sense actually, it would be cheap and easily replaced if it wore out and that was my thinking
when I asked above "is there a shoulder in the spigot?"

My original spigot is inextricably stuck on another very bulged vapouriser (and worse I can't find them anywhere )
I need to examine the burner remains more carefully since if that shoulder was there once it must have been very thin.

Thanks again for the comments, really trying to get to the bottom of this.

 

Here is a the best view I can manage to take up the old burner, it might not show in the photo but there are clean brass marks on the air tubes.
I suppose my drilling did that.



Zoomed and examined more closely...



Just to show it is going well again tonight with the replacement burner



I hope it will continue to work like this for a long time!

 

I've just had a quick look down a burner spigot. There appears to be some sort of shoulder at the exact level of the bottom of the three intake tubes. In fact, the bottom of the intake tubes has removed the shoulder at the three locations they enter the burner. In fact, what I see closely resembles your top two photographs above so the top rim of the vapouriser is in contact with the three air tubes and the three areas of the shoulder in between them. Now this is a burner I've never had lit but I took it off one of my Jacobeans with full lacquer still present so it's perhaps reasonable to suppose it's had very little use and therefore the burner isn't worn.

Anyway, if you had you a known good hood top and burner on another Tilley, you could have tried swopping them over and seeing if that made any difference. As it is, it seems to be burning OK for the moment at least. If you're coming to the Newark Meet this year, bring the lantern and have the experts (not me!) look at it...

 

Thanks for more information David.
I have been thinking on this for a while and I think it is most interesting that your unused and lacquered burner has air tubes which break the shoulder. Can you date that burner - even approximately I wonder?

I would have thought that was a bad idea from the point of view of conducting heat away from the vapouriser - which I am sure is important to avoid it becoming overheated.

The position of the air tube ends in relation to the vapour stream from the vapouriser must matter very much. If the tubes are too short the venturi effect won't happen to
draw in sufficient air, conversely if they are too long they will disturb the flow of fuel vapour. I wonder if there has been any experimentation about just how far they should be screwed in?
It might work like the height adjustment of the J tube in a Petromax design perhaps...

I am still thinking a shoulder at the very top of the spigot might be a good idea.

 

Very interesting....... got have a look at mine now.

 

I gave it another run tonight - in the weather we are having just now.
It lit with just a single pre-heat, I reckon not too bad in -2 degC.
Flash needed for the second picture

 

Looks good John.
Love the snow in the picture.
Snow is something I just never get where I am.

 

Thanks!

Today, by accident, I seem to have acquired another one... It had to be bought for experimental reasons of course!
This one is from March 1973. Looks almost unfired but I smell something like fuel remnants so it has probably run at some point.
Vapouriser looks good and the rest of it is not too bad. I will post pictures soon. It's the burner, spigot and vapouriser that I want to investigate.
I think right now the top is sitting on the cage rather than the burner contacting the vapouriser. It all needs a good looking at before trying to fire it up - tempting as that is!

 

The top is meant to sit on the cage - that's perfectly normal.

Y'know, Jon, in general Tilley lamps and lanterns are very simple beasts capable of withstanding a lot of neglect and quite a bit of abuse. They're not particularly temperamental and no fine adjustment is required or even possible - they just tend to work without fuss. The X246B must be the simplest of them all. With all due respect, I'm getting the distinct impression you're looking for problems that just aren't there so my advice would be - don't think about it, don't faff about with it, simply get it lit...

 

That's where I think there is something wrong with traditional wisdom David. I used to think that but I have changed my mind.

This one is really pretty clean other than some gunk in the tank. Here it is as I picked it up.
Notice the position of the fuel cock, it's pointing out back away from the pump.



Here's the vapouriser, a flat rimmed one. I'm pleased it is one of those.



The pricker end is in good order. Notice absolutely no carbon. The vapouriser is hardly discoloured so
this one has not burned for many hours at all.



The rim inside the burner is very good. Looks like the air tubes are steel - I spy rust?



The seals are completely shot. The one on the control valve is OK so I have just
lightly removed that rim of rust on the shaft in case it affects the seal. Fuel filter gauze is made one
piece with the body. My 1964 one is brass and threaded so removable - we find a 1970s cost down exercise!



Luckily in the cupboard was most of a service pack so it was easy to replace them.
Thanks to @phaedrus42 there were also Peerless DT140s so it got one of those.

Now the clocking of the fuel cock is like this. Fuel cock is front facing and to the right of the pump.
That can of course change according to how tightly the seals are compressed but I reckon it will be fuel tight.



Best of all now the top is clear of the cage. It spins freely on the joint between the vapouriser and the rim inside the burner. It is only about 1mm of clearance to the cage but I think this has been missed before.

Once the seals get old and over compressed that joint opens up, the heat path is gone and the vapouriser overheats. That was the reason for all my problems. If I am wrong I am only wasting my own money on it. I would rather buy rubber seals than vapourisers - a lot cheaper! Actually this whole lamp was less than I have spent on a vapouriser so if it works I will be well pleased with it.

I need to muck out the tank now before firing it up!!

 

I was under the impression that that solved pretty much everything.

 

Here it is - the new mantle is still forming to shape.

It ran for an hour before rainfall made it wise to abandon the experiment.
A cracked glass is not required. Otherwise - I think not too bad.



The snow has gone now - but it is quite bright. It will improve once the mantle forms a better shape.

 

Up to a point extra pumping will bring increased illumination because extra fuel is being burned. But beyond that point, extra pumping has no beneficial effect and merely hurts your thumb. If we're talking about the X246B them extra pumping causes the tank base to dish down because of the way the tank was made and the solder seam tears apart. Such tanks are dangerous and fit only for the scrapyard...

 

@David Shouksmith

Thread diversion alert.

On the subject of extra pumping, I know you are a fan of giving Colemans a good pumping (“until your thumb hurts”, I think is your expression).

Now, both you and I wouldn’t do that with a Tilley, especially the 246B, but I do it often with my Colemans, and sometimes fit bigger mantles to take advantage of the extra “flow through”.

Well, over the past few months I’ve been having conversations with a veteran of the pressure lamp industry here in Australia who said, in a passing comment, “we used to get at least 400cp out of the Aladdin 1As”.

I returned to the subject recently and asked “how?”. The answer was “...a very clean vapouriser, and increased pressure”.

Cheers

Tony

 

@Tony Press - alert noted Tony.
What is something with a Preston Loop doing in here?

I don't mind. I'm doing more running in of the Red one from 1973...

 

Once I had the red one going it seemed too hard to resist attempting to compare it with the gold one.
So here they are!




I am pleased with both. It might not be detectable in the pictures but the gold one wins.

The mantle is better shaped and the light is absolutely white. The red one is still a little yellow but there is no halo visible on either of them. I think the red one just needs to catch up on some running in and get a better shape to the mantle.

 

Just for fun I tried swapping the burners/hood/mantle assemblies between the two lamps.
The red one is original Tilley 1973, the gold one is a Juliands burner from Ebay. Mantles in both cases are the same.

The Juliands one burns the brighter of the two on both lamps so maybe it has a slightly better air supply? It definitely burns absolutely white.
One thing I noted however. On removing the burner assy from the gold one it was stuck on the vapouriser. Oh-no! Is this the dreaded swelling up problem come back again?

Luckily not, they did come apart with some effort and they are unharmed. What it appears to be is some reaction between the very clean steel of the new vapouriser and the clean brass inner of the spigot - there is a fine red/brown residue in there a bit brighter than normal rust. That was sticking them together. Sorry no picture until next time - much too busy panicking.

I hope this is just a "running in" problem. Clean metal faces reacting against one another. I hope once they have each formed some oxide film on the surface it will stop.
I am keeping a careful eye on it and making sure they are free to move each time before starting up. If it continues then I will have to conclude that the spigot and the vapouriser
might be just a little too close in diameter and it is a tolerance issue.

Just in case anyone treads this way in future.