Tilley X246B 300CP vs 500CP differences

Hi all,

Tilley have informed me categorically that the only differences between the 300CP and 500CP variants are (a) length of spigot and (b) mantle size.

However, Base Camp market a 'Tilley 500CP five-inch vapouriser'.

I have given considerable thought to this, and have read numerous posts on the subject. Technically, one would anticipate that 40% more light would need 40% more fuel throughput. Whilst the longer spigot and larger mantle would enable the standard vapouriser to evaporate 40% more paraffin per second into vapour, using a standard 300CP vapouriser and its standard sized jet orifice, you would need 40% more tank pressure; am I right? I'm reluctant to risk damaging a tank by over-pumping.

Does anyone know for definite, before I shell out £21 to buy one, whether a 500CP vapouriser has a bigger jet than a 300CP vapouriser or differs in any other way?

I have a 'scrap' 300CP vapouriser which causes flaring outside the mantle, presumably due to a worn jet - would this work in conjunction with the 500CP spigot and mantle?

Sorry for so many questions and thanks for any advice,

Phil

 

Yes, that's my understanding, too...

Why? - what's your reasoning behind that?

The Tilley instructions quote a higher number of pumpstrokes for the 500 version. I can't remember off the top of my head what it is but 130 comes to mind. Mind you, Tilley just call the lamp with the longer spigot and larger mantle the '500 series'. IIRC, it's left up to the user to assume light output is actually 500cp. I don't believe in Santa Claus, the Tooth Fairy or the Easter Bunny either...

Yes, I've wondered about this one, too. Firstly, you'd have to assume that the 300cp vapouriser in good condition was capable of vapourising more fuel than a normal-sized jet could pass. It follows that a worn (i.e. wider) jet might be expected to pass more of this surplus vapour into the burner. Secondly, you'd have to assume sufficient (i.e. more) air could be taken in by the burner to produce the correct mixture with the extra fuel vapour. Lastly, you'd have to assume that the mixing could be accomplished completely in the mixing chamber before combustion. That's an awful lot of assumptions.

My feeling is that the modern Tilley X246B is a pretty crude weapon and all this theorising is probably a bit wasted...

From experience, my X246B 500 series is a big disappointment and what with the large greyish areas on the mantle, I'd stake my life on it not producing 500cp. I don't think it's that much brighter than the standard 300cp version - which won't be producing 300cp anyway.

As an experiment, I had my mate machine up a longer spigot for a Bialaddin/Vapalux burner. I stuck a Tilley 500 series mantle on that.

Nope, that didn't much increase light output either...

 

Hello Phil, this topic has been discussed before on this forum and I have just checked the Tilley website and they no longer offer the 500 series lantern or spares for it.

The 500 series was Tilley trying to boost their sales without producing a better lantern and instructing folk to pump more pressure into the X-246B tank, which cannot handle extra pressure for long.

I would put that £21 towards another lamp, Jeff.

 

Hi Phill as mentioned this has been disscussed on here before,i my self have mentioned this as i have a 500 series X246B,and i am sure it was David, that mentioned the same as you it is only the spigot and mantle that is different,the 500 series was brighter,but as all so mentioned the procedure was to pump more air in the tank,so the mantle could be filled with more fuel air mixture.
But the tank was not modified to take the extra pressure,so a lot of them the bases started to blow.
I all so contacted Tilley, and they all so confirmed it is only the spigot and mantle,that was the difference,so i would just buy a standard 606 vapouriser.
And to be honest i changed the spigot on my 500 series, for a standard spigot as the mantles for the 500series, are scarce and there is no danger of damaging the tank,which is why the 500 series was discontinued,but i have kept the original spigot so i still own technicaly a 500 series

 

Yeah - try one whose name begins with either a 'B' or a 'V'.

 

Or take a »P« with real 500cp output

 

David and all,

First, thanks for your interest and I appreciate your bearing with me, as a Tilley fan in the company of so many Vapalux, Bialaddin and Petromax enthusiasts. However I'm going to stick with Tilleys, for now at least... and sorry if any of this is repetitive, but my searches have clearly been inadequate.

Regarding my assertion that the longer 500 series spigot would cause the vapouriser to evaporate 40% more fuel than the shorter 300CP one, this was based on the assumption that vapourisation would occur along the enclosed length of the vapouriser between the bottom of the incandescent mantle and the jet at the tip. The longer spigot increases the length of the vapouriser that is enclosed by 40%.

I have since re-thought this hypothesis after taking some more measurements. In fact, vapourisation will probably only take place along the length of the vapouriser which is actually enclosed by the mantle and spigot, i.e. the hottest part sitting within the flame. The upper part of the vapouriser, from the top of the mantle to the jet, sits inside the burner above the mantle, outside the zone of combustion, so this portion of the vapouriser is probably just providing a degree of superheat to the paraffin vapour.

The 300 series spigot measures 1" long and the 500 series spigot is 1 7/8" long, 87.5% longer in fact, so the vapouriser could be capable of producing up to 87.5% more vapour per second, rather than 40% more as I had previously calculated. The true effect is probably somewhere between these two extremes. Nevertheless, I think that this is not the main point.

To force up to 87% more vapour through the standard jet orifice will require considerably more air pressure in the tank, and this is where this design comes unstuck. However I think I've read about someone using an older, stronger X246 Guardsman tank with a 500CP mantle and spigot to good effect. I have the parts, so I may try that idea myself, although I prefer to keep lamps in as original condition as possible rather than swapping parts between lamps.

For what it's worth, Tilley may not list 500 series mantles on their website but they do sell them, at £1.50 each. You have to order by telephone. Three arrived in today's post. I'm still intrigued by Base Camp's '500CP vapouriser' so I might telephone them to ask how it differs from the standard one. Probably just the writing on the box...

Plenty to experiment with as the longer, darker and colder nights approach!

 

Well, it seems to me that the fuel will begin to vapourise wherever the temperature of the vapouriser is above the boiling point of kerosene. Given that steel is such a good conductor of heat, I strongly suspect that zone starts somewhere well below the mantle/spigot area.

 

This seems to be quoted at around 150 degrees C, but a few degrees higher in practice due to the pressure.

The latent heat of vapourisation of paraffin is 251 kJ/kg. It's the rate of heat transfer through the steel walls of the vapouriser and into the liquid fuel that's important, rather than the temperature itself. If I could remember enough of my college thermodynamics I could probably work it all out. You're probably right though, and evaporation takes place from further down the vapouriser. It would be interesting to look at the pricker wires of heavily used vapourisers to see where the carbon deposits start and finish. As you say, this is probably academic, but I've always been interested in reverse engineering!

Phil

 

I have measured the light from my 500 some years back. It had a near new burner and vaporiser and gave me a stunning 246cp at the recomended pressure. From the instructions that is 150 pump strokes which is 50% more than the 300 series. I have not worked out what increase in pressure that gives but it will be well in excess of 30psi.

Tilley did list a 606-500 vaporiser for a while and the implication was it was somehow more powerful than the standard 606 but I have always had my doubts about that idea and from what they are now saying it seems I was right to doubt. ::Neil::

 

The carbon deposits are invariably at the top where the vapouriser is hottest. But then these arise from a completely different process to vapourisation. I suppose it might be termed, loosely, as 'cracking' where, due to the very high temperature of the vapouriser at the upper part, some of the hydrocarbon molecules of the fuel vapour are broken down into smaller ones, including carbon.

I'd venture to suggest that during normal running i.e. everything up to temperature and at equilibrium, very little, if any, fuel still in the liquid phase gets as far up the vapouriser as the burner spigot area...

 

It's interesting to speculate on these issues. I may be able to borrow an industrial infra-red non-contact thermometer to check out our suspicions.

 

My experience is that a 500CP is physically bigger in every dimension and you will need a 301 vapouriser again a lot bigger bore

 

Not in the case of the X246B, it isn't - see the title of the thread...

 

I have now polished the inside of the mixing chamber and air tubes, fitted a Tilley X500 mantle, fired up the 500 series X246B and compared its brightness (by eye) against an X246 Guardsman and three other X246Bs.

The difference is, I have to concede, marginal, although the 500 series lamp is just a little bit brighter than the others. However this may be due to my unwillingness to pump any more pressure into the tank. I chickened out after 140 strokes.

I am waiting for a light meter to arrive, at which point I will conduct some slightly more scientific tests. I also need a brand new vapouriser for another lamp, so I'll order a 606-500 from Base Camp and conduct the ultimate comparison, hopefully proving one way or another whether the 300 and 500 series vapourisers were ever any different.

Some further thoughts. I've played about with a 'worn' vapouriser and come to the conclusion that it's not simply the diameter of the jet orifice that affects the lamp's performance, but the shape of the vapour jet as it leaves the vapouriser tip. This must be crucial to creating the ideal reduced pressure zone needed to entrain sufficient air and cause the correct mixing needed to burn the fuel. Whilst a worn vapouriser may pass more fuel at a given pressure, the vapour jet shape may be compromised and so it doesn't automatically mean a brighter burning mantle. When insufficient air is available, the flame that burns outside the mantle obviously contributes nothing to its incandescence.

If anyone can help confirm or refute the above theory, it would be much appreciated!

Phil

 

I can do neither but it seems a perfectly reasonable thesis to me...

 

Thanks for that, David.

Apparently the 500CP doughnut-style Tilleys used a physically much larger burner than the one used in the X246 range, as gazluka suggested. It would therefore appear that trying to extract 500CP out of an X246 of any age is going to be difficult if not impossible...

 

Hello Phil, check out the links below, Jeff.

Tilley 500cp., do-nut lamp burner unit.


Tilley 301 vaporisers, three different styles..

 

Hi Jeff and thanks for the pictures/links.

I presume the 301 vapourisers are all 500CP rated ones from the larger lamp.

Base Camp assure me that the jet orifice diameter in the 606/500 vapouriser is bigger than the one in the standard 606. This does make sense. One is on its way to me, and I'll report back once it has been fitted.

A light meter is also on its way so I will be able to report some comparative results.

Phil

 

So Tilley say there's no difference between the vapourisers fitted to the X246B and the 500 series. On the other hand, Base-Camp say that there is.

Now I wonder who supplies Base-Camp with the 606/500cp vapourisers they have on offer. Couldn't be Tilley, could it..?

 

Well I can. I heard a while back that some German Petromax fanatics were extending the life of a jet by smoothing off the top on an oil stone. This has the effect of correcting any ragged edges to the hole and they claimed it improved performance.

I then found it made a dramatic difference to some new Blanshard jets Malc had made. In order to drill these jets had a centre pop dimple and when used like that they were crap with yellow flames and black mantles. We knew the hole was the right dia so remembering the German rumour I ground the tops off flat and when the fettled jet was tried the lamp worked very well. It made the difference from non functional to pretty good.

I also resurected a rusty Kitson jet the same way. This was again pretty much non functional because the jet would not fire straight. They are actually made with a conical exit with the jet hole central. This one was so rusty the hole edges were rough and the jet was firing gas all over the place but almost none up to the mixing tube. So Malc ground the end down to a flat profile for me and now the lamp works perfectly.

So yes the profile is at least as important as hole dia if not more so. ::Neil::

 

Could it be that the same part simply becomes known as "X" part for the latest product number/type?..

This seems to be true of galleries etc for some wick lamps.

 

That is fascinating information, thanks Neil.

I've got a worn Tilley vapouriser which is probably beyond hope as the hole is enlarged. I've spent some time inspecting the jet orifice under x20 magnification and comparing it with a brand new one, and it's hard to tell any difference. Sadly I only have a hand-held lens.

However, I've found that a simple but effective test is to blow gently into the jet end of the vapouriser and try to judge the resistance and the amount of air flow. Whilst this is not a definitive test for a worn vapouriser - and it helps if you like the taste of paraffin - with a bit of practice and listening to the air whistling through the tube, it is certainly possible to tell a worn vapouriser from a good one.

I'm impressed with the precision nature of this crucial part of a pressure lamp. Does anyone know the actual correct diameter of the hole?

Phil

 

Tilley, whilst helpful, seem not to be very knowledgeable about their products! I am away for a few days but by the time I get back, the 606/500 and the FC meter should have arrived, and I'll get down to some tests to try to prove the point, once and for all.

Phil

 

Maybe you need a travelling microscope or similar to measure the diameter of the jets.

More simply, I wonder if it would be possible to check how far the prickers protrude on each version and then swop them over. If there is a diffference in jet size, that should become quickly apparent - one pricker will protrude further and the other will protrude less. In theory, anyway...

 

A 300 cp jet should be 0.2mm or 0.0069" ::Neil::

 

Thanks for the info Neil, that's good to know as I measured the diameter of the tip from a good cleaning wire using a micrometer, and that was exactly 0.2mm too.

I assume some wear of the hole itself is tolerable, up to a point. I haven't come across many worn ones, which is fortunate as the vapouriser is then scrap.

Phil

 

Well, after a relatively long wait for the 606-500 series vapouriser and the vintage Avo Model 3 light meter to arrive, I have finally been able to take some comparative measurements of light output. I set up a test rig with the light meter set to the footcandle range and the lamp in fixed positions, exactly one foot apart, then measured the brightness of four different Tilley lamps.

I have normalised the results so that, on a scale where the least bright lamp reads 1.00, the others can be given a "percentage brighter" rating:

Standard Tilley X246B.....1.00
Tilley X246 Guardian 1.....28% brighter
Tilley X246 Guardian 2.....57% brighter
Tilley X246B-500.............71% brighter

These results are interesting because the apparent difference in brightness when judged by eye was nowhere near as marked as the light meter readings would suggest - see the photo. The X246B-500 was certainly brighter than the other three, but not apparently by a great amount. My X246-500 is fitted with the longer burner spigot, a Tilley 500-series mantle, and a Tilley 606 '500 series' vapouriser.

If my standard X246B gives out 300CP (and I doubt very much that it does) this means that my X246B-500 gives around 513CP.

I'll be taking this lamp to The Fleece at Bretforton next weekend and hope to be able to compare its brightness with someone's 500CP Coleman or Petromax... that will be really interesting!


Phil

 

I agree absolutely!

 

Great info on the 500 series, however, I’ve seen stated that the tanks wasn’t modified… just the spigot and mantle. the lamp I am currently working on has a slightly different tank with an extra hump in the top, with the frame shape slightly different to accommodate. I presume this is to strengthen the tank somewhat for the extra pressure.