Milton Loco Works burner- we want... information!

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brianthesnail96

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<p>For my dissertation... </p><p>Do the Milton burners increase run time for a given "setting" of the gas regulator over a standard Accucraft one, or do they allow you to turn the gas down lower to keep the boiler at the same pressure? Trying to work out which tree I'm supposed to be barking up here. I suspect it's the latter one! </p><p> Attempting to work out theoretical burner efficiencies, i.e. what percentage of the potential heat enregy availiable from the butane do they actually allow to be converted to useful energy? I have no idea how I'm going to do this at this moment in time... Assuming the same amount of oxygen is availiable to both burners, incomplete combustion must be occuring- to a greater extent in the standard burner than the Milton one. I just can't work out why! </p><p>There might be a simple answer, it's been a long day- I've been trying to do my thermo coursework as well...
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How about looking at the efficiency of mixing the air and gas? I see the Accu burners with a long tail of gas burning poorly down the firetube, away from the hot part of the flame. I wonder if some form of induced turbulence or swirl after the air entrainment stage would help? It's all the rage in IC engines. 'Twin Swirl Combustion Chamber'......(Suzuki)

Or is the space available insufficient for all the mixture to burn? Is the placement of the burner in the flue critical? Are they made straight? Just wondering if they need to be right up against the top of the flue.

I've just run an Accu Baldwin tank, that was the best accu burner I have experienced - steamed like the clappers, as quiet as a roundhouse.....easy to light...coudn't take it apart as it wasn't mine (brand new, not altered at all), but looking up the flue it looked like the same old burner - why should it be so efficient in comparison???? Confuuuused!
 
Stop making my life more complex you!

I suspect it is all down to mixing- the holes are more spread out than the slots, allowing better mixing (and also possibly more "swirl" as you say) and therefore more complete combustion. Complete combustion can't be occuring otherwise it'd be impossible to make it more efficient! No idea how to calculate it though. Will ask my fluids lecturer on Tuesday- I'll bring the Accy burner in so she knows what I'm on about!
 
The other thing about the Accucraft burner is the slots are angled toward the front of the locomotive. The Milton burners holes point straight at the inside of the flue. I think by angling the slots it moves the flame front forward more quickly than if it shot straight at the inside of the flue. I have made replacement burners similar to the Milton units and it seems that having the flame aimed straight on makes the burner work better. More of the heat is transfered to the flue instead of just jettting down the flue towards the stack. The holes also seem to mix the gas and air together better than than the slots and hold the flame against the burner at higher burner settings. I found that the flame would float off of the slot burner and go out if turned up too much.

Charles M
 
New Haven Neil - 15/11/2009 5:15 PM

How about looking at the efficiency of mixing the air and gas? I see the Accu burners with a long tail of gas burning poorly down the firetube, away from the hot part of the flame. I wonder if some form of induced turbulence or swirl after the air entrainment stage would help? It's all the rage in IC engines. 'Twin Swirl Combustion Chamber'......(Suzuki)

Or is the space available insufficient for all the mixture to burn? Is the placement of the burner in the flue critical? Are they made straight? Just wondering if they need to be right up against the top of the flue.

I've just run an Accu Baldwin tank, that was the best accu burner I have experienced - steamed like the clappers, as quiet as a roundhouse.....easy to light...coudn't take it apart as it wasn't mine (brand new, not altered at all), but looking up the flue it looked like the same old burner - why should it be so efficient in comparison???? Confuuuused!
Click to expand...

The Baldwin boiler is smaller than the freelance engines and is lagged (i think).
 
The bottom half of the boiler on the EMR's Lawley is lagged... definitely helps and easy to do too. Next time it's apart I'll take some piccies.
 
I take the lagging comment on board regarding efficiency, but that still wouldn't make any difference to the sound?

I should be able to reflect on an experience from a few years ago of steaming a full size roller without lagging - took a whole lot longer than it's usual time.
 
I recall that thread Matt, but I don't accept lagging the boiler can reduce the sound of the burner. Is the boiler shell resonating? Despite being filled with what is effectively damping fluid? I would need a direct comparison measured properly to accept it, I suspect other things are at play here, smokebox/flue volumes or something like that?
 
Laura seems to know a lot about steamies all of a sudden...

Surely putting the mesh over the burner effectively turns the slots into holes? I know that's what it looks like when you peer down the flue anyway.
 
<p>Matt may I suggest you try and get Chris (albula from GSM) involved in this too. Is he on here?</p><p>And did you join <a href="http://groups.yahoo.com/group/Steammodelloco16mm/">http://groups.yahoo.com/group/Steammodelloco16mm/</a> ? There are people on there who know about this stuff.</p>
 
If the Milton burner is so much better (and the ones I've seen have been) and holes are better than sots, why do Accucraft persist with slots? There must be a reason for it.

From what I've read, the Countess has exactly the same burner but due to the lagging the burner doesn't have to be turned up so high, hence it is quieter. I haven't seen a Countess running so I can't confirm any of this unfortunately.

On a slightly different note, the Ceramic burner in my Cheddar loco is fantastic. Why aren't these used by more manufacturers?
 
I agree with you wholeheartedly James!!

The answer is likely to be - cost - on all accounts! :wits:
 
johnsaintjim - 16/11/2009 1:38 PM

Laura seems to know a lot about steamies all of a sudden...

Surely putting the mesh over the burner effectively turns the slots into holes? I know that's what it looks like when you peer down the flue anyway.
Click to expand...

I tried mesh on my Accu Mortimer, and it was a disaster. The flame burned out of the smokebox door about two inches, until you turned it down so far it wouldn't keep any pressure. This is really odd, as it was the same mesh exactly that Bradypus used (he gave it to me!!) and his is fine, as is everyone else's that has tried this!!!

I haven't had time to experiment further.
 
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New Haven Neil - 16/11/2009 1:36 PM I recall that thread Matt, but I don't accept lagging the boiler can reduce the sound of the burner. Is the boiler shell resonating? Despite being filled with what is effectively damping fluid? I would need a direct comparison measured properly to accept it, I suspect other things are at play here, smokebox/flue volumes or something like that?
Click to expand...
</p><p>Seems wrong to me too Neil, I've no idea what causes it. Sadly I can't afford one to research... I suspect James is probably on the money though.
</p><p>Really should join there Graham. Don't like the format of the Yahoo groups though. Chris is indeed on here, he is using his name now though. Adding mesh effectively converts to holes, except I suspect that it actually increases the amount of radiant heat due to the heating of the mesh to red 'ot. Not sure though. Apparently the Milton burners are better than the standard meshed burners though. </p><p>And yes- slots over holes due to cost I reckon. It works OK so why spend more on production?
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I've been wrestling with myself trying to decide how much difference the smaller boiler on the Baldwin makes to steaming, it is about 20% smaller than Edrig etc. It won't be a linear relationship, so maybe more than i was at first thinking. It certainly steamed like the clappers, so you could turn it down more which does of course make it quieter, but even full on it's quieter than the others.

Maybe it's the small smokebox that makes it quieter too. Looking at the flame it appeared to have a very stable shape, wish I could have pulled it apart to have a look! My Mortimer is never that good, I must examine the slots more closely to see how they are formed, and clean them up maybe.

Chris H certainly gained a great deal of knowledge building his spamcan, I think his final design is a radiant type though. That is the way forward I am convinced, for efficiency, and James comment regarding his Cheddar burners supports this. So does a glance at a gas fire.

...but not a gas boiler....he says, now glancing combi-wards......different methods of heat exchanging.....mmm, off for a think!
 
Does it have a sealed- or more sealed- smokebox? Just wondering if that'd affect the air (and butane) flow, different draughting?
 
<p>Generally, holes seem to be better than slots - as suggested by Charles M above. One possible reason is simply size - if a poker burner is 10mm dia then a 1mm quarter slot will be about 8mm<sup>2</sup>. A 3mm hole on the other hand will be nearer 28mm<sup>2</sup>. The larger the hole, presumably the slower the gas air mixture, and therefore less tendency for the flame to lift. Looking at a piccy of the Milton burner the thing is peppered with holes, so must be less obstructive than the slot burner. I don't know what happens if the burner is restrictive, but my guess is that you get a less than optimal gas air mix. It could just be that the slot burner gets in the way more than the Milton burner.</p><p>Btw. If you do a Google search for 'Milton burner' this thread is the second response - fame at last Matt :applause: :applause: </p>
 
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brianthesnail96 - 16/11/2009 10:28 PM Does it have a sealed- or more sealed- smokebox? Just wondering if that'd affect the air (and butane) flow, different draughting?
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</p><p>I'm not sure that the smokebox would make a difference, but a tight seal between the burner and the flue would. My Accuraft burner is a loose fit and probably draws cold secondary air into the flue. Might be time to seal it up properly :thinking: </p>
 
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