Looking to fettle an old and beaten up Anchor 999 I ran into some weird trouble described here Anchor clone pulsates heavily unless control wheel is in 10 o clock position After much fiddling I realized that the eccentric block is very small compared to the inner diameter of the lower generator tube. It also has a vertical ridge on the back that was intended probably to act like a guide. Therefore I came to the conclusion that at some point either the lower generator or the control rod assembly were replaced, resulting in a mismatch. If any of the other Anchor owners can be bothered, it would greatly help me to have some reference pictures of the original eccentric block, eccentric spindle and lower generator. Thanks in advance for any help.
Eventually I figured it out myself, all the parts were the correct ones but the previous owner had at some point installed the double threaded part 107 the other way around. So the bit going inside the lower generator wasn't long enough and allowed the eccentric spindle (part 105) to disengage from the eccentric block (part 103). I now have the lantern correctly assembled but that didn't solved the pulsation/breathing problem. Time to figure out what other problem it may have.
I was about to dig out the Anchor but good you have it under control. Others are more able to make suggestions on your remaining issue. Cheers
@Adrian , the anchors are a petromax clone, or very similar, if you look in the refrence gallery you may find your answers, Pulsating usually can be associated with the fuel pressure, the heating of the generator turning the fuel into gas, the sometimes as it vaporises the preasure pushes fuel back dowm the generator , picture the temp being hot and cold, dose it have the preston loop, is your inside of the gen very clean, this helps, also in the hood there may be a screw mix where the bapour and air mix, if so you may be able to cange the mix, also try a lower preasure, last of all use a big long peerless mantle, it will heat your vap more efficently and evenly, i hope this helps,
Pulsations can usually be drastically reduced to the point where they're not noticeable by using brass gauze in the upper generator. But then, most, if not all Petromax-type lanterns were designed or built without the gauze in the Preston loops. I have a hunch that the pulsing originates almost entirely from the particular Preston loop generator of the problematic lantern. I wouldn't go into very lengthy elaboration on the exact science or mechanism on how that could happen here. In short, too much fuel reaches its vaporization temperature around the loop before it could escape via the jet orifice. It could be due to locallized overheating due to poor conductivity of certain brass used for the generator. It could also be caused by thin-gauged construction of the generator(a heavier/thicker construction is less prone to this problem). Whatever it may be, try swapping the generator with another having a thicker construction, which has a lower fuel volume in it.
Thanks, it's not the generator as I already swapped it on another lamp (together with the top assembly) and it was working normally. The only three possible culprits remaining were the control assembly (just fixed that), the generator valve and the fuel itself.
Does it still pulses when you pump in higher pressures? Too low an operating fount pressure could sometimes be the cause. If that's not the case for this, do inspect the fuel pick-up tube and the foot valve area to see if there're are leaks above the fuel level, which could also sometimes be the culprit. A tiny leak of fount air into the fuel pick up could evade detection.
I am suspecting a weak foot valve spring at this point. The problem is that I don't have any spare lead spacers so I cannot disassemble the lower generator too often. Higher pump pressure sometimes fixes it temporarily. However it also requires fiddling with the control wheel. I believe that the weak spring of the valve allows the fuel to be pushed back in the fount by creating a pumping effect (the fount overheats when the lamp does the deep breath/deep pulse thing).
The foot valve is supposed to open completely when you lower the pricker rod. Unless the lower part of the rod only marginally displaces the foot valve pip against the spring, its not too likely to cause pulsing. In case it is, the spring could easily be replaced. But again, do check that the lower rod is only touching the pip when you turn the pricker knob up. Sometimes a wrong eccenter piece could make this incorrect. Or the lower rod somehow been shortened by someone previously. Another possible but unusual cause is that the horizontal slot at the eccenter piece is worn, allowing too much 'play' whereby the pricker rod would just be hanging on loosely at the pricker knob stem-end. You can use some PTFE tape around the threads if you don't have a spare lead washer. Having said all these, I'd say the lantern would still work even you completely remove the foot valve, leaving just a plain fuel pick up tube. ***The non-rapid type Petromax and clones do not have a foot valve.
Actually this is a non-rapid clone but does have a foot valve. The eccentric control assembly now works perfectly, after I figured out the problem mentioned above. However your diagnostic may be correct, as the lower rod IS adjustable on these clones and it appears to have been adjusted on the short side of things (it engages the valve when rotating the control knob beyond 4 o'clock). I didn't paid much attention to it. Looking at how the Sea Anchor clone is adjusted from factory it appears that there is some minimal play between 12 and maybe 2 o'clock but beyond that the valve is engaged. I will try to adjust it the same on the Anchor and see if it sorts out the problem.
@MYN looks like we were both correct: the adjustment of the lower part of the rod fixed the Darth Vader breathing/heavy pulsation AND the foot valve spring IS weak. When pumping to 2 bar during preheating the lamp almost turns itself on. It won't go like 100% unless I turn the control wheel but it goes quite bright. Not really a big deal since it's not a Rapid model but will change the spring and valve gasket jut for good measure. Lamp goes like a champ now, with 17mm air gap there's no trace of smell of unburnt fuel.
It looks like your persistence had just paid off. The diagnostics was pretty tricky because these are not the usual causes of pulsating lanterns. Possible but not common. I've had once, a long time ago, where this was giving me similar problems. Pulsations, in addition to sudden mantle dimming, sooting and then turning slightly brighter for a short moment before dimming again. The adjustment of the lower rod was marginal at its lowered position, resulting in a partially opened foot valve, with the spring inadequately compressed. The end effect was a 'flapping or chattering' foot valve pip during operation, sustaining the pulsations.
Or should I say: contributing favourably to the conditions where pulsations could be sustained. It might not be the root cause why the pulsing could be initiated in the first place but it almost certainly reduced the resistance to a back-flow intò the fount.
In my opinion the root cause of the pulsation is the Leidenfrost effect. If the valve is not opened completely and the spring is weak this causes the valve to start acting like a piston,vastly increasing the pulsation. In any case, thanks for the help, I was convinced that the lower generator was the only suspect left (after swapping the upper gen and the "hat" assembly), but it turned out to be the lower rod adjustment. I suppose this is why on the original Petromax there is no lower rod adjustment. Probably the Chinese factories are using these rods on various other lamps, hence the need for an adjustment there.
Well, after another round of fiddling with the lamp the Darth Vader breathing and pulsation returned. The major problem that I had was that the threads on the Anchor clones jet are different from the ones on original Petromax and SLIGHTLY different from the ones on Sea Anchor clones. So I could only test with Anchor and Sea Anchor jets (I knew the Sea Anchor ones were already worn). Now, running out of solutions, I took a Petromax 350CP jet, used a copious amount of mantle string soaked in dishwasher liquid on it and Darth Vader was gone. Of course the jet started to leak after 10 mins or so, but the test was clear. However the light output was ridiculously low compared to the full blasting lamp with the enlarged jet, when I use the foot valve to restrict the flow a bit so it will work properly without pulsation. I'd say in that configuration I get 700Cp at the very least. 1 l of fuel lasts less then 5 hours. So it turns out that the major cause is a slightly enlarged jet, plus other minor factors that can change the behavior on a given day. Hope it helps others who may run into similar behavior. This can be however a good way to overdrive the lamp (so to speak) if the jet isn't too enlarged.
Adrian, you got a truly interesting lantern that is just about as 'formidable' as Darth Vader. At this stage, I would have brutely 'napalmed the entire block' and leave no chances for 'survival or rebellion' ...if its mine . I'd be inclined to replace the entire vaporizer(both upper and lower), jet, pricker rod/needle, footvalve, pricker knob stem and anything else on the assembly. But then, that'd remove the fun of troubleshooting and fettling . I've mentioned earlier that in most cases, the culprit is the upper vaporizer. Some have poorer conductivities, have larger internal volumes and therefore prone to overheating on their walls. These vaporizers have inherent qualities which favour the onset of the 'Leidenfrost' effect. So there'd be occurrence of flash vaporization where the fuel is in direct contact with the overheated inner wall. A quick remedy would be to stuff some brass gauze or copper wire coil into the upper vaporizer to:- increase the overall mass of metal, reduce the available volume for the fuel, evenly distributes the heat thoughout the vaporizer and to the fuel as well as forming some flow restriction back into the fount. As for the stubbornly leaking jet, I say use copper or nickel antiseize compound instead of dishwaher liquid, in addition to the mantle tie cord around the threads.
If you get to much fuel for a 350cp jet: replace it with a 500cp jet and needle. Use a copper washer under the jet or mantle threds to slove the leakage there. Use a metall gauze in the vaporiser to reduce the "Leidenfrost" effect. Off coarse everything else has to work fine too.
Guys, you got it wrong The original Petromax jet leaked because the jet threads are slightly different on the Anchor clones. However the test was very relevant, during those 10 minutes until the thread wrapping burned out the lantern worked as it should. So the biggest culprit for summoning Dart Vader was the original Anchor jet which turned out to be enlarged. On the other hand, with the enlarged jet it was possible to overdrive the lantern (vastly increasing it's light output) by increasing the air gap and turning the control wheel until the foot valve restricted enough the fuel flow. It's a tricky job to start it but when you get the control wheel to the right position it will run without problem and make insane light (this morning one of the neighbors asked me what was that huge light in my backyard last night ) The main problem of that configuration is the fuel economy, it burns a liter in less then 5 hours.
I made some photos in action so you can see what I'm talking about. Lamp on the right is the Sea Anchor clone with new 350CP jet and bad J tube, lamp on the left is the Anchor with it's enlarged jet and running full blast without Darth Vader breathing using the foot valve technique. First photo is taken without flash, second one with flash.
I can see what you mean. A slightly enlarged jet orifice could sometimes give additional lighting output. So would you like err..700cp from that? Well its unlikely to reach those figures if you measure with a lux meter. I've had a Petromax with a similar output due to that. It does not pulse but gets way too hot for comfort. The fount was so hot after less than half an hour of operation that I couldn't touch it. The radiant heat was eccessive and I had problems getting close to it in order to top up the air too. Its too small a frame to operate comfortably with those 600...800cp ranges. Parts would fail sooner.
I didn't tested with a lux meter but will give it a try using one of those phone apps. (using the light sensor of the phone). To he naked eye it looks clearly more powerful then 500CP, not something marginal.
Those lanterns rated 500cp seldom attain the actual figures themselves. The same goes for 350cp ones. There are exceptions though. From the picture, its doubtless that the unit with the enlarged jet orifice was clearly brighter. If it doesn't appreciably harm the globe, the upper vaporizer or the parts around the J-tube in the long run, I'd say you've got an awesome piece. From my experience with similar lanterns, the jet usually wears even faster than usual under these conditions.
Measuring LUX with a telephone ? Buy a LUX meter from ali and built your own acurate lightmeter setup for lanterns.
I know what you mean but if you read the various articles on the matter it turns out that a decent smartphone with a good app will stay within 5% from a decent luxmeter setup. For the purpose of this discussion that's good enough (and with zero cost)
