Have come across a top and burner for this one, so the hybrid SDR/246 may not be needed, but, I have a question about the burner...... the burner, fits into the holder nicely and the upper reflector goes under the holder....... when bolted together, how does the air get to the air tubes? I have only managed to get an orange flame outside the mantle......... air flow, worn vapouriser or worn burner ?? I have tried another vapouriser and burner from a Guardsman...... not much improvement......... am I missing something??
I think air flow into the burner is via the gap between the upper reflector and the hood - there are three spacers to keep this gap as open as possible but oxygen intake is always going to be a bit compromised. You could try undoing the three nuts holding on the upper reflector and have a look inside. Best of luck and do let us know how you get on...
Ahh, spacers........ didn't come with the original nuts and bolts so the reflector was against the burner holder. I'll try some washers and post the results.
Try running it temporarily with just the burner i.e. without the reflector fitted - or even without the rest of the hood. Or a spare X246B hood would do the trick and let you assess the state of the vapouriser and thus the original burner...
The SDR is an odd design - because it will consume its own exhaust where almost all other Tilley's are clearly designed to draw in fresh oxygen. Very strange.
Tilley may have managed a few innovations but I don't think they ever managed to re-write the laws of gas stoichiometry. The products of combustion rise and pass through the central hole in the upper reflector, past the burner sides and are then exhausted through the three slots in the hood just below the cap. I suppose it's possible some of the exhaust gas could get taken into the burner again but I'd think that was incidental rather than deliberate. Half of me wants to unscrew the three nuts holding on the upper reflector to see what's beneath and get a definitive answer. Only half of me...
The route you describe for the exhaust gasses is correct, of course. But the air to the burner is drawn from the small gap between the top reflector and the brass hood. And that is largely sealed by the glass from the outside world. I've taken a couple of SDR hoods apart and there is no secret passage from the air tubes to the uncontaminated atmosphere See here also Tilley SDR type 1 too Now, the SDR burns OK and no doubt finds enough oxygen from the draught through the bottom reflector and upwards (albeit mixed with the products of combustion) - as well as a bit of leakage around the top of the glass, maybe - but that is touch-and go with the diameter of the glass. But it is at odds with most (all?) other Tilley lamps that are carefully designed to draw fresh air. The PL 53 and X246's take their air bellow the top vent - and other models such as FL and ALs have extended air tubes to admit fresh air. Much the same with indoor galleries. But not the SDR. It seems odd that Tilley viewed the principle as important both before and after the SDR, but not for this model which can't have been a budget offering.
I've looked at both of my SDRs and I think it's the other way around - the glass is a pretty close fit around the steps in the upper and lower reflectors and seals the air intakes from the exhaust. The air intakes themselves are at least 6mm outside the glass, so are taking in fresh air only. Incidentally, the spacer(s) maintaining the air intake gap between the upper reflector and hood is/are present on the Dutch SDR only. There's no sign of it/them on the pork-pie version I also have. The reflector on that is poorly engineered compared with the later lamp. Maybe it's re-used aluminium from a crashed Heinkel or Spitfire or something...
My pork pie SDR came with no spacers between the reflector and hood. That's why it wouldn't work ! Thanks to Neil for explaining this to me. For those who are not familiar with an SDR, the hood does not sit on the frame like it does on an X246 but the burner (within the hood) rests on top of the vapouriser like it does on a PL53 and the table lamps. This leaves a gap for the air to flow over the rim of the glass and up between the reflector and hood to the air tubes. Therefor, the height of the glass is critical, it should be no higher than the frame it sits in. Without spacers between the reflector and hood, this fresh air must follow the contours of the reflector which take it along the same path as the exhaust gases where it becomes contaminated before entering the air tubes which in turn lead to a poor burn. A crap design. The air tubes could so easily have been extended to the outside of the hood and fitted with air buttons like those on a PL 53. You're too kind, I'd have thought that crashed aluminium kitchen foil would be a more accurate description. Henry.
I'm a bit surprised (read, totally baffled) by this - I appear to have two SDRs constructed completely differently to yours, Henry and to the one Ian is describing...
David, Some of that which I wrote yesterday was from memory and I made a mistake. Today, I dug out my SDR and re-examined it. The gap between the frame and hood/ burner/reflector assembly is not created by the burner resting on top of the vapouriser as I stated. It is created by the nuts on the bolts which hold the hood/burner/reflector assembly together as a unit. Other than that, I'm sure I'm correct with my description of the airflow. Refer to the images here Tilley SDR type 1 and note that the reflector is slightly smaller in diameter than the hood. 1) Fasten the gallery with burner inside the hood. The nuts (if still in existence) act as spacers. 2) Locate the reflector and secure with the second set of nuts. It is these nuts which act as distance pieces between frame and hood. Because of the smaller diameter of the reflector, there is a gap around the circumference between it and the hood which allows air entering over the top of the glass to flow upwards into the void (created by the spacers) between the reflector and gallery/hood, where it then enters the air tubes. I'm sure that if you re-examine your Dutch SDR, you'll see that this is the case. If your pork-pie SDR burns cleanly without spacers, then you Sir, are a miracle worker. Achieving a clean burn when most of the air is in actual fact, oxygen depleted exhaust gas, defies logic. Henry.
Following the comments I have taken the top apart and taken some pictures As can be seen, without spacers the holder and reflector are touching both inside and out creating a sealed chamber the air tubes draw from, therefore no air to mix with the fuel. I moved the nuts between the two parts and this seems more sensible. Now to repeat on the lamp to compare the burn.
No mantle or glass....... Burner holder and reflector fixed together With the nuts put between the burner holder and the reflector
I am truly amazed at the burn achieved when the reflector is held tightly to the gallery. Mine was no where near as clean as that and when I fitted a glass, it was abysmal. Henry.
Thanks, Henry. Putting aside the Dutch SDR for a moment, I've never tried to light my pork-pie SDR and nowhere have I said that I did. Therefore I can make no claim to being a miracle worker - I think, Sir, you assume too much! My guess would be that someone has been tinkering with the hood ( perhaps trying to improve the burn?) and has re-assembled it incorrectly. Yes, exactly what I was saying to Ian with my remark about stoichiometry! With respect to the Dutch SDR, this has what appear to be 6 spacers, only the ends of which are visible, but resemble large washers possibly. These maintain the gap between the reflector and gallery assembly and the hood which is surely how fresh air gets in to the gallery and thus the burner. Now on my Dutch SDR, this air intake gap is well outside the glass (as it is on the pork-pie SDR) so takes in fresh air from the, er, fresh air surrounding the lantern. There's no obvious need for air to go "over the top of the glass" - not obvious to me, anyway. Both of my SDRs are fitted with the correct globes, both having an oval at the top with the words PHOENIX 78 HEAT RESISTING within the oval and the words TILLEY MADE IN ENGLAND without. Due to, I assume, manufacturing tolerances, there is a clear difference between the lanterns in the position of the top of the glass relative to the top of the globe cage - it's about 3mm on the Dutch version and about 6mm on the English. The top reflector of the Dutch actually sits on the top of the globe so there's no way air could pass over the top of the glass. The top of the English SDR actually does sit on top of the vapouriser but the gap between the reflector and top of the globe is so small it's highly unlikely that significant amounts of air would be able to pass over the top - certainly nowhere near enough to satisfy the needs of a hungry Tilley burner in full flow. Anyway, pictures are clearly needed but it seems a shame to be faffing about inside on such a nice day, so maybe tonight. Cheers...
I did notice that without the spacers the hood and burner wobble about on the vaporizer, whereas with them the the hood sat nicely on the frame. The bolts that the hood came with were definitely not original as they were 20mm long
Quite right. My proof reading was in haste, instead of stating :- I should have said :- If you can achieve a clean burn without spacers etc., etc. I should also have made it clear that my observations were pertinent to my personal experience with my own pork-pie SDR. Humbled but not downtrodden, I still think that the height of the glass is significant. In the case of my pork-pie SDR, I eventually achieved a decent burn after putting spacers between the reflector and gallery, however, there was no glass in the lantern at the time. The only available spare glass I had at the time was one intended for a Tilley gas lamp, which as you know, is taller than the correct glass (part number 78). With this taller glass fitted, the light output decreased, at least to my eyes. After grinding the glass down until the top of it was level with the frame the light was brighter again. Hence my reasoning. Henry.
Well my SDR is in the shed at the far end of the garden and the way the weather is at the moment, getting there would be akin to being on the deck of a North Sea oil rig in a force 10 storm, so I ain't going ! I do have another (unadulterated) Tilley gas light glass but that is in a cabinet which in turn, is buried in the garage. So no images from me either. Henry.
Fitted a mantle and ran the lamp for a while at low pressure, 30 pumps with tank half full. Increased pressure and burn diminished to a white glow, Photo taken after shut down, guessing a burner issue, but it looked ok before the mantle was fitted - see previous pictures of burn before mantle?
@KAB If it's any consolation, my SDR often burns like that but quick flick of the cleaning needle usually cures it. @David Shouksmith Managed to break the glass on my SDR when getting it ready for a photo' shoot so it's at the back of the shelf waiting for me to calm down. Took me ages to grind the best part of 1/4 of an inch off it so that it would fit and now i'll have to do it all over again. Henry.
