LAMB - a burner prototype

Mister Occlusion · LAMB - a burner prototype

I just want to state right off the start that I have no practical idea of what I'm doing here. In headspace everything works loverly, but realspace is a different environment where the laws of physics trump the desires of ego.

So this is a journey of discovery. Like the title, I am making things up as I go along, and who know what the outcome will be.

So, to preface, LAPMB: Light Air Pressure Meths Burner

As stated elsewhere, I've been kicking this around in headspace, on and off, for months, ever since I was messing with the chicken feed system and noticed how nice big and blue a flame I could get when I blew very lightly into one of my fuel lines when the burner was nearly exhausted.

I've been scheming up a way to introduce air into the fuel tank of a meths burner to provide a *very* small amount of combustion air into the system. At first I was hoping I could find a passive solution, but realized that a hot burner (tank) filled with meths is in no way ever going to be in a negative pressure situation (IE meths vapour simply pours out of the vent hole on these things.)

I thought of various mechanical means of injecting the air though some engine driven device, but in the end I believe the prototype will be run with a small aquarium compressor.

Now, in this design it is absolutely paramount that no liquid should ever flood the fire tubes, since the air will push it out and make a nice flaming pool. The tubes must be fed from the fuel tank by wick alone, so once again I am borrowing the Bowman style concept.

I'll be trying to put this together over the next few evenings. For me, the soldering is going to be a bit of a challenge.

Here are the photos of tonights progress

The main components: 3/4" Brass square tubing (fuel tank), 3/4" Copper pipe cap (Air dome), 1/4" copper tube (fire tubes). The Jensen 75 has a high firebox, and I am going to take advantage of that.

Had to think about this one for a while. The pipe end cap would substantially overhang the brass fuel tank. Most robust solution? Squash it into an elliptical shape in the vice until it fits atop the tank, then take the belt sander to it to level the bottom off.

Copper tube has been annealed, cut, and rolled into reasonably straight fire tubes

Preparing to solder the fire tubes

Pulling the wick into the fire tubes. This will be impossible to do later on. This is the same rope I used for my Jensen 65 burner. It was much easier to pull in this time because I did not cut the flame holders into the tubes beforehand this time.

A fairly snug hole drilled into the fuel tank for the wicks. The object will be to avoid having too much air vent into the fuel tank.

Mocked up inside the engine

the flame holders drilled. I suspect they are too small, but it is easier to make them bigger than to make them smaller. We'll know when it's time to preheat and light the bugger.

Still to do:

Solder Air dome to fuel tank.

Fabricate and solder end caps on to fuel tank.

Drill small vent hole on top surface of fuel tank

solder a fuel inlet line about 2/3 up back side of fuel tank (will be using the remote tank to fill it)

Solder another brass line into the back of the air dome. This will be where our low pressure air source is hooked in.

Solder a few magnetic pennies to the bottom of it

You see what I am trying to do, I hope. I am essentially wanting to make a sort of blow lamp, but with the air passing through the burner rather than over the flame.

I know that, based on what I've already observed, it should work and, hopefully, not pose a danger. The fuel supply is reasonably isolated and prevented from intruding into the tubes, even as it expands - because excess fuel will back flush into the remote tank.

If this sounds like a good way to blow myself up, let me know

Otherwise... Hopefully I can keep the momentum going and get it finished and tested before the weekend. I do not have an air supply yet, though. I could always use my lungs for the first trial

igy569

It sounds OK. ust wear a face mask, have the wet cloth, and fire ext. may not be a bad idea.

But that does sound like it will work IF you can keep the pressure low enough. The aquarium pumps move a fair amount of air. I have run engines on them.

Mister Occlusion

It may well be necessary to have a bypass in the air line, then... That's a good idea. Air flow must be regulated.

Don't want to melt the fool thing after all..

I would still prefer some sort of engine driven air pump in the end. Perhaps a large bore oscillator could move enough air to do it...Something like a Jensen 60.

Baby steps: see if it works, then worry about making it nice

...I don't have a model 60 to rip apart anyway (yet..mwahahaa..)

Titan

It would be advisable to keep the 'flame holders' a small diameter - below a certain size a flame cannot travel through the hole. This might be important if you do not want a flame accidentally burning inside the tube.

rangerssteamtoys

It looks like a good start. But the wicks might bee to big, so when air is introduced, meths will not burn and simply come out via the little holes.

But a small steam driven air pump is a god idea. Steam meths burner sounds cooler but probably not possible.

I could imagine the jensen 60 as the pump

when its running slow the flames will like to jump

Nick

Any progress on the burner?

igy569

Hey.. a way to get some very low air pressure.

Take a small plastic T fitting, like for vacum/washer tubes in a car.
Drill a small hole through the cap of a plastic juice bottle, force the T fitting in to the hole, and then screw the cap back on to the bottle, attach a hose to the fitting where it pokes through the top, and gently squeeze the bottle.

Gives you a easy to control air flow, and if you let go of the bottle, you should get negative pressure, so just watch out for that... and mostly, please don't blow yourself up!!!!

I figure the rest will become real obvious.

Mister Occlusion

Honestly I've not had a chance to get back to it yet.

I would like some automatic air source, but first we'll get the theory proven and then worry about the mechanics. If I have to I'll just blow into the air hose for the first tests.

I'll take another crack over the weekend. Too tired tonight to make an honest effort.

One update, though, is I thought up a more clever acronym that rools off the tongue better.

Light Air-pressure Meths Burner.

Yes, if it works maybe one day more people will be lighting a LAMB under their engines

igy569

Absotutly!

jamespetts

Very interesting idea! I should be interested to see any videos of that working.

Had you ever thought of a system involving burning a vapourised spray of spirits (kept alight by a small flame from a wick), by pressurising spirits through a small hole in a similar way to the sort of water spray hand-can that one would use for the garden, but with brass instead of plastic? The spirits could be pressurised by having a sealed tank into which air is pumped. It could be refilled like a boiler, with a hand pump and a check valve.

Mister Occlusion

John "Bogstandard" posted a sketch a while back of a similar sort of burner, save that it used heat-vapourized meths injected into the burner tube. Gassified as opposed to atomized.

I'm hoping to get some more work done on this one today.

I bought a small fish tank air pump yesterday, and in a moment of blissful clarity I decided to use one of my aluminum spice tins (IE: what my remote meths tank is made from) for an air reservoir.

It's leaky, and the top turns to expose a sequence of holes, which will make it even more leaky.

It's my though that a very Minimum amount of air will be needed, so a means must be had to bleed off the excess air coming from the compressor, without restricting the flow (which is hard on the compressor).

Yes, the spice tin should work just fine as a pressure regulator.

Also got a nice stainless cookie sheet at the dollar store for testing it on, so any stray fire does not stray too far.

...just have to get my month-end reports done and some rubbish cleaned up before I can play... I hate doing month ends

Mister Occlusion

Well... I finished and tested it over the weekend, and it was a disappointment.

The theory seems sound: it burns with a larger (mostly) blue flame when air is injected than it does without.

The execution was lacking, however. I knew this thing was going to burn lean, actually that was the whole point: burn lean and hot and use less fuel.

The problem is, as someone pointed out earlier, is with the wicks. Once the fuel in the tubes is expended - I prime them by injecting meths into the open ends, the burner slowly peters out. The wicks just can't draw the fuel in fast enough, probably due to the distance from the reservoir.

I don't know if I can retool this one to correct those problems. If I remove the "air dome" and mount the tubes directly into the reservoir maybe, but then I'll have to be very careful with the fuel level, lest the air blow liquid out the tubes.

I'll have to hook this one up to the air pump and let it run for a day or so to evaporate all of the meths out before taking a torch to it...

Will post a few pics in a bit... my net connection bites tonight. There's not much to see, however, outside of my horrible soldering job

{edit: photos added}

Here's what NOT to do if you want to succeed....

The entire setup, with air regulating can and such... Did a quick wipe to white of the areas of no interest in order to save on the file size and make for a less cluttered presentation.

Pump and regulator

The "lit" pictures are not very good, and don't show it at it's best anyway, so I will not bother linking them.

Like I said: a disappointing first prototype

rangerssteamtoys

Well, I have tried this before too. With an old muffler from an r/c car engine. It worked well with air being supplied via air brush compressor.

If you want to hear what I think On this idea, here it Is.

Wicks will never work, you need a 1/2" pipe with about 3 holes in it. At the end you have your little meths tank and an air hose for injection. Have a pan underneath this pipe to serve as a preheater, the heating of the pipe will make the meths evaporate and light throught the 3 holes. NOW you add the air which blows the vapor out the holes creating a giant BLUE flame. To supply constant meths to the burner you can have a 1/8" tube with a crimped part in the middle. This will keep a slow steady drip of meths into the burner.

Hope this helps

Mister Occlusion

Well, I wanted to create something that was reasonably safe to operate, rather than being a jostle or misadjustment away from chaos and fear.

Simplicity of construction is a plus too...

If I was going to have a fluid pool in the burner I'd probably go with vertical tubes and do the style that we had been working on last summer with the brass shell casings.

That begins to lack simplicity when you've got to construct and silver solder an air manifold to 3 or 4 upright tubes....