Coleman 226 fuelling

The lantern’s the one I took on my ‘Snow Trek’ and is working fine, but I removed the valve and fuel/air pickup assembly from the tank, curious to know which of the Easi-Lite types described and illustrated in THIS excellent post on the Coleman Collectors Forum my lantern was equipped with.

Of those depicted it most closely resembles that listed as for the 222A lantern, with no fuel/air metering rod installed in the fuel/air pickup tube.






The valve and f/a pickup assembly. Two O-ring seals on the control spindle and a brass valve body (not aluminium) distinguish it from the CCF example.




The O-ring on the eccentric block ...




... mates with the chamfered seat in the valve block when the control is turned to ‘off’, shutting off fuel flow to the generator.




The fuel/air pickup, concentric tubes as in older Coleman lamps and stoves ...




... but without a metering rod operating within the inner tube as would be the case in prior Coleman products. The fuel pickup orifice is much smaller than is usual, and I have to confess I’m stumped as to how the ‘easi-start’ function occurs with this type. Ideas anyone?



John

 

My best guess is that the fuelling borrows on Coleman Apex gasoline camp stove technology, extract from the stove patent here.






The essentials, as I understand it, are a very small bore fuel inlet (smaller than is usual for a Coleman fuel/air pickup) and a restriction - a damper - in the fuel passage within the valve.

This damper is the component already pictured ...




... the lower end of which, together with the O-ring enters this space in the fuel/air pickup tube’s mounting sleeve.




When the control knob is set to ‘High’ the damper is lowered by the control eccenric into that cavity and restricts fuel surge.

The effect of that combined with the pinhole fuel inlet is to establish correct metering of fuel and air without reducing the pressure of the air above the fuel too quickly.

It clearly works, but isn’t from the example I have as willing to light up initially as my similarly sized 222 lantern with its conventional Coleman fuel/air pickup tube equipped with a metering rod/plunger. Neither does it run as long without top up pressurising with the pump.

 

@presscall
Sorry, i don't agree on your explanation of fuel air mix in last 3 paragraphs below the last picture.

If the o.ring of exzentric block would restrict the gas mix in fuel pick up,
it would just dim the lantern.
It does so, when turning clockwise, but via seat in the valve block.

The start gas mix mechanism is different.
When at start the vapourizer is empty, the gas volume flow is identical at gas tip/jet and the pickup tube. This rises some fuel through the small hole in the end of pickup tube, plus an larger amount of pressurized air via the larger hole at upper end from pickup tube. Resulting in meagre gas mix for match lighting start without preheat .

After some while in this operation, the fuel level in pickup tube and valve block should rise to the generator in liquid form.
When gasoline is evaporated in the generator, it creates large amount of fuel gas. Fully satifying the gasvolume passing the jet orifice. Less volume of pressurized air will be drawn from tank. Gas mix runs richer for normal operation.

That should be the normal operation.
But many 226 do not run good. Because this process depends highly on fuel liquidity and proper dimensioning relation of jet orifice and puckup tube base hole.

My 2x 226 don't run well and waste way too much pressurized air from tank.
Much pumping required.

Some physicist might correct me....

 

That’s fine, alternative explanations were invited and welcome.

 

Created an account, just to poke at this thread. Looking at getting a 226, because I want a dual fuel option, and I like their look more than the 229 and 3022, but have a need to understand how it works, so I can adjust, if I get one that's... recalcitrant.

You both have viable perspectives, but I'm struggling to understand the available paths in the FA tube. Side note: the FA tube *function* seems to be that of an emulsifier, as found in a carburetor, and I agree with John's assessment that it at least roughly follows the intent in the patent listed. But exactly HOW is what is bothering me.

Since I don't have one in my possession to disassemble, I'd like to ask a few questions of those that do, and either have or can get better understanding of the passages.

From my visual understanding, it looks like the "damper"/eccentric block is lifted to close off the air/fuel mix entirely, seating into the chamfer in the T-block. When the knob is turned, air/fuel is allowed to rush past, and is then metered by the orifice in the end of the generator. I think everyone agrees on that.

What I'd like to know:
1. Has anyone cut open an FA tube, to see if there are any extra holes in the inner tube, which would function as emulsion bleeds?
2. At the bottom of the FA tube, there is a "collar" of sorts. Is that *completely* sealed to both the inner and outer tubes? If not, which one is in clearance, and where?
3. At the top of the FA tube, in the threaded fitting, is there a gap around the inner tube, inside the outer tube (which is clearly soldered into the fitting), or is it completely sealed so that the only flow path is through the inner tube, into that fitting (this would require emulsion holes lower down on the inner tube, for the outer to do anything useful)?
4.a. Inside the threaded fitting at the top of the FA tube. Is the ID straight or tapered?
4.b. Is there any point inside the fitting where the eccentric block o-ring would be capable of sealing off the flow? If so, does the eccentric block have enough travel to get there?

 

Before getting a 226 you have to decide what you want to do with it.

I bought mine NOS at a car boot sale because I thought it was cute and the price was right. It had never been lit but the generator was corroded and needed to be replaced. That cost almost as much again but it has been very useful and I don't find it
hard to light if you listen for the tell tale hiss & sputter which means it is time to apply the match.

As said above once it is going you will have to add pressure frequently. This means it is OK as a carry around lantern for doing odd jobs outside in the dark. I have decided it is my user for that. 10-15mins is enough to squash a few tins for the bin. Last night it went for a walk to the post box.

It is not the one to choose for an evening at the camp site. Much too frequent attention required.

 

Let's try to stay on topic. I appreciate the caution, but I'm wanting to sort out how this particular design works, as is the topic of this thread. I'm not asking for advice. I'll do that on another thread, once this one is fully sorted.

Back on topic, and having dug through a couple other pictures and threads: One picture I've seen, the "collar" is removable, and the outer tube of the FA tube is continuous to the bottom surface where the hole is. Which would imply that the inner tube is sealed at the top (in the fitting), and stops short of the bottom (inner) surface of the outer tube. Can anyone confirm this?

 

@M4v3r1ck

From what I can understand and works similarly to even the current production Powerhouses.

At start, pressurized air will take the path of least resistance which is usually from the holes on the upper side of the fuel pickup, this rushes down torwards the pickup oriface which that area is normally flooded.

When starting the instant light circuit. This submerged section of the pickup is immediately is purged of fuel and sent to the generator. The tiny constriction of the pickup is insufficient to refill that section as the air continuously sucks the pickup oriface dry, sending the mixture of broken partially atomized droplets of fuel to the generator providing enough of a vapor for you to ignite.

Once ignited. The liquid fuel rapidly vaporizes and expands and builds pressure as a gas. Enough of this pressure is built up that the backpressure from the heated generator is enough to rapidly and significantly reduce the net flow to the generator and tip. This allows the pickup oriface to replenish and become submerged once more, isolating the outer air circuit in a moat of its own fuel.

From there the fuel has direct access to the inner section of the pickup and is forced to the burners.

Hope this helps. I'm bad at explaining.

 

It certainly helps and is the best explanation yet.

@M4v3r1ck
There’s a patent number on the lantern’s collar.



The patent:

The description and the accompanying schematic drawing (reproduced below) differ from the production outcome for the FA pickup however, not least in having a metering needle within the inner concentric tube. It does use an O-ring on the eccentic block within the valve to shut off fuel in the ‘off’ control knob position though.




On closer inspection of my lantern’s FA tube I’ve established that the inner concentric tube is not sealed to the fitting at the top as you suggest it might be. It resembles this arrangement.




That begs the question I’ll grant of where exactly is the inner concentric tube mounted? Presumably at the inlet end, but sectioning the component to confirm that is something I’m unwilling to do, you’ll appreciate.

 

@presscall

Do you have closer photos of the upper holes?

 

@Dashwood
I’ve had the FA pickup out for this latest discussion but can get nothing better than this enlarged, increased exposure, existing shot. It shows the air gap (it’s not a shadow) between the inner and outer concentric tubes, confirmed with a blast of air from an airline.

 

Bit strange that the gap allows egress of air.

 

Man, that is REALLY weird, having a gap at the top. If the FA tube followed the patent (even without the needle), it would act like an emulsion tube, and at reduced flow rates, you'd get JUST fuel, with no air being pulled from the fount. With that gap, the metering of air is going to be constrained by the gap, which is going to be REALLY hard to manage, with the fuel inlet at the bottom getting less and less "pressure drop" as fuel level gets lower. Does the Inner tube "rattle"/move in the fitting (radially or axially), at all? I have to wonder if it was originally press-fit, and fell out, which, if endemic to the series, would explain all the complaints of excessive air consumption.

As your part is, the AFR is going to be constrained mostly by the ratio of the "air gap area" and the size of the fuel port at the bottom, and it looks like it's going to be REALLY lean, under most conditions, probably flowing more air than fuel.

 

Of note, this is my reference for one that has a removable lower collar. But it looks like the eccentric block is one of the "down sealing" ones, not an "up sealing" like the one you're showing.

 

No, it doesn’t.

I’m thinking it works as a simple atomiser.




I’ve restored a ‘Tillite’ pre-heater for a Tilley lantern and the similarities in concept are striking, having an inner concentric tube to provide the fuel with an outer tube to convey pressurised air to the atomiser - blowing air across the fuel outlet tip, aerosol fashion.

 

I should add, it’s a working lantern, so the FA pickup hasn’t become dislodged and the running characteristic (a requirement for more frequent ‘top-up’ pumps than is usual for a pressure lantern) is as those of other owners of the type that I’ve spoken with.

I’d forgotten about that photo. I must ask @Henry Plews how he detached that piece: Henry, I see no sign of threads. Interference fit?

 

@presscall @M4v3r1ck the "lower collar" is an interference fit.

I don't know if it's pertinant but the lantern is dated 1 - 93

 

@M4v3r1ck

That would explain alot actually, the later peak lanterns had atrocious runtimes inbetween pumps as the pressure is rapidly used up. Most surmised it has something to do with the generator's oriface being wider which lead to increase consumption. The larger oriface was tailored for use with RUG fuel.

 

I’ve heard that suggestion, but I think it’s wrong. The attached file source gives a 0.005-inch orifice for a 222 lantern, opened up to 0.0055-inch for 222A-B and 0.006-inch for a 226. It seems to me that the larger sizes aren’t larger by a significant enough amount to explain the 226’s tank pressure drain. The FA configuration explains it in my opinion.

 

@presscall

It would also explain why some experiments were performed using the original skinnier factory 222 generators on 226's and beyond. Users reported almost nil improvement in consumption.

 

Larger generator orifice was probably to account for the leaner AFR created by the "atomizer" style FA tube. That really is such a strange decision to make... The only reason I can think of is that gasoline has some relatively heavy components that aren't found in camp fuel, which wouldn't vaporize at the typical generator temperatures, so it had to be atomized, instead. I ran into that, running my zippo on gasoline. Eventually, the wick was full of those heavy leftovers, which wouldn't boil off, and the lighter wouldn't light... until I heated it up a LOT, and then it burned happily. Once that was over, I was able to use it as normal again.

Edit: The inner tube has a machined groove visible in the air inlet window. The lower section of the outer tube looks to be swaged slightly, to retain the inner, and the outer collar locks it in (I think). If someone has the guts to try it... when the outer collar is removed, is it possible to shift the inner tube up/down in the outer tube? This would allow for the adjustment of that atomization and AFR. The machined groove would let you set the position in the air inlet window, to get some precision to your adjustment.

 

@M4v3r1ck

Except for one thing, the net flow entering the generator is way too slow for any atomization to occur in that area once the lantern is lit and heated.

Gravity would naturally keep the liquid fuel at the lowest point as air would simply bypass acting against the fuel and escape out the top section of the pickup instead.

What I'm strongly leaning into what's actually happening is either poor manufacturing design oversight or an ingenious design balancing thermodynamics but poorly executed.

Hypothesis A: The poor manufacturing cost cutting theory.

Traditionally, instant light fuel pickups were brazed together, both inner and outer tube. The inner tube was probably tricky to braze together as the risk of the tubes coming apart by mistake with improper heat application. Coleman probably surmised they can probably get away with swaging and press fit the inner tube together inside the pickup, the tolerances after the fit are probably tight and minute enough that the surface tension of the liquid fuel inside that tight space is enough to prevent or slow the leakage of air as if to not drastically disrupt the operation of the lantern. But heat and other elements at play can easily disrupt those tolerances (i.e thermal expansion of the outer sleeve of the swage) Can mean air can possibly leak out overtime and reduce the runtime between pumps. A technical oversight from this cost cutting or shortcut. This is probably why Coleman has never revisited this design.

Hypothesis B: Easier ignition for heavier domestic fuel like gasoline.

This theory plays more in line with your theory by initially leaning out and impregnating the cold fuel flowing with lighter volatiles mixed in the pressurized air of the fount. Additional vapor rich air is introduced into the already atomized fuel from the pickup, breaking the broken stream even further for easier light. Once the lantern is in ignited, net flow decreases and the trick of thermodynamics takes over. Heat now conducts down from the hot generator and works down into the upper swaged section of the inner tube, expansion squeezes the already tight tolerances of the inner tube forming a tighter seal to resist any air attempting to escape this route.

From what I gathered. Users of these 226/229 has reported drastically improved economy in-between pumps when the lantern has been running for a while which some probably have attributed the fuel to air level being low enough because of increasing volume of air being introduced that the pressure drop isn't as drastic. When in reality, it's the ever tightening tolerances from thermal expansion of the fit is reducing the air loss.

But the issues with being a press fit rears it's ugly head as seen in the first theory that it's not entirely air tight. Air loss is still significant enough to effect the economy between pumping.

Anyways just a theory. We won't know for sure.

 

@M4v3r1ck @Dashwood

Wrong! Thanks to @Henry Plews and your previous work on this model Henry, I removed the fuel pickup inlet component as you did - a moderate interference fit, so not much force to twist it off the outer concentric tube.




This was revealed, the inner and outer concentric tubes with an air gap between them.




That made me look more closely at the other end and get a better photo in the process.




In my defence concerning my mistaken belief that a (concentric) air gap existed there, the photo shows the consequence of an interference fit between the inner tube and the fitting and not an air gap.

I now conclude that the atomising occurs not at the top end of the pickup tube but at the lower end. The small size of the inlet orifice …




… ensures that there’s no flooding when the control valve is opened and pressurised air from above the fuel is mixed with the fuel drawn through the pinhole inlet and passes as an atomised fuel/air mixture to the generator.

Only, it doesn’t work at all well in practice and I’m done with attending to it with too frequent pumping in use.

I’ve decided to solder a small brass sleeve over the air inlet hole in the outer concentric tube and dispense with the ‘pinhole’ fuel pickup component, easily reversible modifications that a future custodian can dispense with, should they want to. Start-up will be by spirit pre-heating cup.

Here’s a spirit cup I’ve made, with silbrazed construction to withstand the priming and running temperatures it will encounter.








A dry run for fit.




The patent referred to the possibility of running the lantern on kerosene, with suitable pre-heating provision, so that’s something I’ll be trying. In theory, a jet orifice suitable for white gasoline would overfuel on kerosene, but we’ll see.

 

@presscall

I guess the mystery is solved? Guess we'll never know the root cause of the increased pumping intervals on the 226 and later vs the original 222 design.

 

Ok, THAT makes much more sense, as it would behave exactly the same as the originally posted patent, and mesh well with Dashwood's first explanation. I like your spirit cup modification, but I would personally lean towards opening the aperture in the "lower collar", a little at a time (I have quite the collection of very small numbered drills), until the lantern is just barely hard to start. This would supply much more fuel and much less air for a given "brightness setting", at the cost of a bit more cantankerous starting. As fuel level drops in the font, you *could* turn down the brightness (and flow), to keep from wasting air, but it'd be hard to know where the "best" setting would be, since you can't really *see* it pulling air.

WRT the extra air consumption: The earlier 222 models had a needle which blocked off most of the incoming fuel, during "start", to get that lean AFR, but once you set it to "run" or "high", the needle pushed down to let more fuel into the "inner chamber", which, once above the bottom of the inner pipe, cut off the extra air being lost, until fuel level in the font got low enough that it would start bubbling again.

Thank you to everyone for their input and willingness to disassemble and document!

 

@M4v3r1ck @Dashwood
I’m grateful for our discussion, which has resolved a longstanding frustration with this lantern.

A sound suggestion, which I could easily do with the smallest of my watchmaker’s broaches. That may be an experiment in the future, but for now I just want the satisfaction of some decent illumination from the lantern without constantly attending to the pump!

 

Absolutely understandable. Please keep us posted on results! Now that I'm reasonably sure I know how it works, I think I will keep an eye out for a reasonably priced specimen, which I can modify my way, and then we can compare notes, at a later date.

 

Excellent @M4v3r1ck Good hunting! Yes indeed, I’ll post updates to this thread.

 

@M4v3r1ck @presscall

I do have an older 222 lantern with the three position knob and metering rod and it's the easiest lantern to light next to my milspec (it being easier even using a spark igniter I attached to the frame.)

Just turn to light, wait to sputter, bring in lighter and fwomp! It lights without fuss or flare.

 

I was surprised to read that comparison (unless irony was intended!) because I thought a 252 Milspec didn’t set the bar too high for ease of lighting. I got the hang of lighting the one I have but it’s decidedly a knack, and I don’t believe it’s a sickly example.