# Small Gas Poker Burner



## Tony Bird (Sep 19, 2012)

Hi,

This thread might be interesting as I'm not quite sure how it will turn out!  A Danish member of an another forum that I belong to bought a boiler which didn't have a burner.  He had tried using a blowlamp type burner with no success other than melting some solder on a chimney joint.  The boiler is copper hard soldered together 100mm long, 55mm in diameter with a 15mm ID flue which protrudes 15 mm out of the boiler which looks as if it could be professionally made.  The flue has no cross tubes.  I have made quite a lot of boilers and burners some of which have been quite small.  If I had designed this boiler I would have used a larger 22mm flue.  However someone made this boiler which might have produced steam well.  So I got a bit interested as the smaller flue would allow quite a lot of usable water in the boiler, with of course a much smaller heating area.  As I mostly make working steam models i.e. locomotives that run on rails and boats that are used on water a longer running time has a lot going for it.  So a drawing was made that showed the differnce between the two flue sizes and some sums done to see the difference in boiler volume to heating area.  There is quite a difference in this ratio so things didn't look good.  But I thought I would give it a go anyway and made a copy boiler.  This is very similar being a couple of mm shorter (the longest bit of 55mm tube I had) and the flue is 15mm OD not ID as the original.  I'm not sure how long I can work on this so I will do it in short sections.

Regards Tony.

Original boiler.





Comparative drawing.




Testing copy boiler.


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## Tony Bird (Sep 19, 2012)

Hello again,

Following are some photographs of a burner to fit into 15mm copper tubes that was designed many years ago and I have lost count of the numbers made and used.  The burner consists of a plug which fits into the flue, this plug has an offset hole into which the burner itself is a push fit.  The plug as part of it a tube with a pair of air holes in it into which the jet is fixed.  Once the gas/air mix is correct any number of burner tubes can be tried out in the same plug.  The gas tank is mounted on a small wagon that is used to test new locomotives.  The photographs show the various tubes that can be used on the same plug.  The holes in the burner tube are covered with a nickel/chrome mesh Nikchrome?  Alas I cannot find a source of this mesh in the UK and I have just about run out.  I think it came from the USA.  These burners are usually run inverted as in small boilers it is easy to allow the top of the flue not to have water over it. 

The photogaraphs show the first burner made at low and its high setting.  They also show a very short burner which I use in some vey small boilers.  More to come probably tomorrow.

Regards Tony.


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## Tony Bird (Sep 20, 2012)

Hi,

The boiler was fitted up with a pressure gauge and Goodall filler valve and using the 5 slot poker previously shown fired up.  It took about 10 minutes to get the full boiler up to 25psi.  It would power the small single acting engine it was connected to but the pressure slowly dropped.  A smaller range pressure gauge was fitted to watch the drop.  A narrower chimney was fitted to slow down the escape of exhaust gases, it did work but the burner would not light with the chimney in place. A second burner was made having 10 slots, with the original chimney it took 6minutes to get to 25psi. This burner will power the small engine and the pressure still rises and ran for 20 minutes until the gas ran out with still plenty of water in the boiler. When connected to a larger 9mm bore 18mm stroke engine the pressure slowly decreases.  So some more experimenting will be needed with other burners.  Before doing this as the boiler does work and experiment with a similar boiler using heat exchangers in the flue has started.  To be continued next post.

First set up. 





Second pressure gauge used. 





Smaller chimney tried. 





 10 slot burner.





Video




 Boiler lagged.






Regards Tony.


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## Tony Bird (Sep 20, 2012)

Hi,

I think heat exchangers would be the wrong description.  Not sure what the equivilent of solid cross tubes would be called, cross rods?  In very small flue tubes it isn't practical to fit water filled cross tubes, they would have to be too small, weak and I suspect they would cause a lot of turbulence in the boiler.  This isn't my idea but that of the late Colin Binnie to increase the heating area and slow down the exit of the heat.  I have only ever used it in vertical boilers along with another of Colin's ideas an extended cut and twisted flue tube.  In small vertical boilers these additions make a real difference to heat transfer.  Photographs show one of my VB locomotives known as Usk using such a modification. 
So a similar arrangement is going to be tried in a horizontal boiler to see if it will increase its steaming abilities. 


One of the Usks nearing completion.






 Underside of ceramic burner which is sealed to the boiler no secondary air needed.




 Testing that the burner will ignite via the top of the chimney before fitting it into the boiler. The cross rods extend into the water/steam space.




 Checking the ceramic burner used.




 Cross rods and extended flue.






Regards Tony.


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## Tony Bird (Sep 20, 2012)

Hi,

A start has been made on a boiler with a modified flue tube.

Six cross rods soldered through flue tube. 




 Checking it is possible to light the burner which is sealed into the flue tube.




 Futher test to see if the burner can be lit from the top of the chimney. Note the burner is inverted.









 Flue in boiler to check clearances.




 Main parts of boiler.





Boiler soldered together as of an hour or so ago, not very pretty, will look better when it comes out of the pickle tomorrow morning.  Just the bushes to be made and soldered in the boiler and some plugs made to test the boiler.

Regards Tony.


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## Diversion900 (Sep 21, 2012)

Just curious Tony......
How do you go about igniting the burner through the flu tube ?

Cheers, Neil


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## gus (Sep 21, 2012)

Hi Tony,
I share same question with Neil. For now light up was no problem with my DIY  gas burner using small canister
LPG Gas firing a semi-open boiler.Burner design came out from "Steam Trains In Your Garden.
 Was comtemplating building flue boiler but backed off for fear of fire from excess gas when lighting up.
Please enlighten us.

Your silver brazing is far superior to mine. Workmanship in boiler is first class.
Living in apartment limits my sheet metal work scope.Use extruded aluminium to make 
fire box.Flame was a bit high .Trying to get used to burner and gas system.


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## Tony Bird (Sep 22, 2012)

Hi,

Well yesterday morning the boiler came out of the pickle and looked a lot better.






The boiler bushes were made and soldered in.  The boiler was then pressure tested, in this case to 120psi to give a working pressure of up to 60psi.  It is a bit worrying testing a boiler that has joints that cannot be fixed if the fail, i.e. cross tubes/rods.


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## Tony Bird (Sep 22, 2012)

Hi Neil & Gus,

*How do you go about igniting the burner through the flu tube ?*

I  mostly make either working model steam locomotives or boats most of which have their burners in their boilers.  These burners are lit by holding a flame over the top of the chimney and turning the gas on, the flame at the top of the chimney flashing back to the burner.  This is the reason a couple of the photographs posted show the set up of the burner, flue and chimney to check this will happen.  Both the ceramic and poker shown are nearly sealed into their boiler, little or no secondary air getting into the flue, all the air required for combustion being drawn in by the flow of gas.  This means that the gas when lit will either burn at the top of the chimney doing little good or flash back to the burner and heat the boiler.  Some boilers that have opening smoke box doors are lit in the smoke box.  I have no technical knowledge of gas dynamics just what I have learned from reading model magazines and other modellers.  Mostly I just try things out, I wasn't sure that the flame would flash back past so many cross rods in such a small tube.  Many years ago I didn't know it was possible to make a reliable poker burner in a 15mm OD tube.  If anything isn't clear please ask and I will do my best to answer.  If I know the answer!

Regards Tony.


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## Tony Bird (Sep 22, 2012)

Hi,

The next job on the boiler should be making the fittings and burner but on Monday we take our model steam railway to the Netherlands for a model exhibition so it will be a couple of weeks plus before any more construction can be done.  So nothing complicated was done in the workshop today the boiler was painted with VHT paint, lagged and fitted to a temporary base.  Tomorrow we try and remember what we have forgotten for the holiday!





















With a 6 inch ruler to show size





Regards Tony.


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## Diversion900 (Sep 25, 2012)

Boiler looks great Tony.
I would never have thought of lighting a tube burner that way though, I have now learnt a new trick    Thanks Tony


Cheers, Neil


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## gus (Sep 25, 2012)

Please enlighten Gus.What is VHT paint and where I buy them??


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## Cogsy (Sep 25, 2012)

gus said:


> Please enlighten Gus.What is VHT paint and where I buy them??


 
Here in Australia, VHT paint is Very High Temperature and is made to paint automotive engines. It actually requires high temperatures to fully cure. It can be bought from any auto parts store. I'm guessing that's what he's referring to as it's on a boiler.


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## Tony Bird (Oct 8, 2012)

Hi,

Sorry for the late reply we have been away.

*Here in Australia, VHT paint is Very High Temperature and is made to paint automotive engines. It actually requires high temperatures to fully cure. It can be bought from any auto parts store. I'm guessing that's what he's referring to as it's on a boiler.		*
*				__________________
				Al.*

Yes same here in the UK and it is what I use.

Regards Tony.

* 


*


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## Tony Bird (Oct 9, 2012)

Hi,

Been away a bit in the Low Countries had a great time playing trains.  While away I did some sums to see how much extra heating area the six rods gave in the 15mm flues usable length giving 3605 sq mm of heating surface the rods added 516 sq mm about 14% extra.  Whether this will make much difference we will have to see.  While doing the sums I worked out that 10 rods could be fitted in the same length which would give a 24% extra heating surface.  Photographs show the 10 rod flue and it being tested whether it would light which it did.  In the next couple of days I will make some plugs for the bushes and see if there is an improvement in steam production.

Regards Tony.


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## Tony Bird (Oct 13, 2012)

Hi,






The above set up using the boiler with cross rods and a 10 hole burner will continuously power the 9mm (3/8") bore 18mm (3/4") double acting engine. So it would seem that the 6 cross rods fitted in the flue tube really do make a significant difference to the steam production of the boiler.  The next step is fitting rods into the flue of a a boiler for a small steam locomotive being built.  This model uses a commercial made chassis, it will be interesting to see if the boiler produces less, as much or more steam than the larger boiler it replaces.


Video.





Regards Tony


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## Tony Bird (Oct 14, 2012)

Hi,

Members of HMEM might be interested in how the poker part of the burner is made.  A piece of 1/4" K&S brass tube is use. 





First filled with a piece of wooden dowel then marked out.





Pilot drilled then opened to finished size.





Drilling finished.





Wood drilled out.





Drilling completed.





End crimped.





Other end slightly deformed to create friction fit.





Completed poker part of the burner.





Fitted with mesh.





Test.





Test in boiler.

Any questions please ask.  A number of burner boiler plugs have to be made for stock I hope to show their manufacture later.

Regards Tony.


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## steam58 (Oct 14, 2012)

hi
very nice 
would like to know more about the burner


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## gus (Oct 14, 2012)

Your thread has given me a very good idea on the gas burners used with the vertical and horizontal boilers.
Was plannning to build both but chickened out but was looking for enlightment.
Plan to build both boilers next year.Now still scratching my head on the Glow Plug Engine that just won't run.

Please advise silver solder rod content. I use higher silver content for ease of brazing. Air conditioners' silver solder rod can be tough to melt and run. Plan to buy a double torch Mapp Gas Torch after watching demo.

Your silver brazing looks good and the pickling good too. Very professional.Mine tends to run all over.


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## Tony Bird (Oct 15, 2012)

Hi,

*very nice would like to know more about the burner *

The burner was designed many years ago and a lot have been made.  They are designed to work in a quite small tube in this case the flue tube has an ID of 13.5mm (large1/2") the OD of the poker with mesh atached is about 8mm so there isn't much of a combustion space.  So the flame needs to be low in height and preferrable wide.  The burner itself is designed to have interchangable pokers that can have different numbers of slots of different shapes.  The burner will work if necessary with no secondary air or it can be put under a pot boiler.  As I make mostly model railway steam locomotives the plug of the burners being built will have a flame viewing hole drilled in the plug.  This done because being slightly deaf and operating in often noisy exhibitions it is with the aid of a dental mirror to see if the flame on the burner is lit.  Once the gas/air mix is correct it is possible to change pokers for different boilers this often done with my test burner shown up until now in the photographs.  This test rig is used to check out locomotives when they are nearly finished without the compllcation of using their own gas burner systems.  Or if it is a new design what type of burner will be needed.  Now as it has been seen it was used to help design a burner.  I hope to describe the construction of the remaining parts of the burner in this thread.  If anything so far described isn't clear please ask.

Regards Tony.


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## Tony Bird (Oct 15, 2012)

Hi Gus,

Sorry I cannot help withyour glow plug problems.

*Please advise silver solder rod content. I use higher silver content for ease of brazing. Air conditioners' silver solder rod can be tough to melt and run. Plan to buy a double torch Mapp Gas Torch after watching demo. *

At the moment I am using Easyflo No.2 silver solder and flux which melts at about 640C.  Sorry I don't know how this compares with solders used in the USA.  The pickle I use is Citric acid which I get from Home Brew/Wine stores. The powder is mixed in hot water until the mix is saturated.  I.e. when crystals that won't desolve appear in the mix.  I use a plumbers gas torch with interchangable heads fed from a large bottle of Propane.  I always use a torch head that is too large so the job heats up quickly. 

*Your silver brazing looks good and the pickling good too. Very professional.Mine tends to run all over. *

Solder will run over any part of the job that has flux on it so paint the flux on carefully where you want the solder.  Warm the joint slowly so the water content of the flux mixture evaporates rather than boils and runs all over the place. Hope this helps.

Regards Tony.


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## Tony Bird (Oct 15, 2012)

Hello again,

Plugs for several burners have been made,  I hope the photographs convey how they were made.




























































Regards Tony.


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## gus (Oct 15, 2012)

Plan to make same boiler.Have plans from from old issue ME magazine.

Plan to buy the twin torch MappGass Burner. Will need two burners from experience gained from past boiler projects.Living
in a low rise flat and locked up in small balcony space limits my expansion plans to go into bigger projects.

Copper pipe bought years ago but need to make end cap former.


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## Tony Bird (Oct 16, 2012)

Hi,

Yesterday made a sleeve to fit into the plug to hold the poker.  The sleeve is made from a 9/32" K&S brass tube with a piece of 1/4" K&T brass tube inside it as a stop for the poker.  The 1/42 tube is made a little too long to form a shoulder that works as a guide for the soldering, this shoulder is turned off after soldering.  The 1/4" tube is slightly deformed using a 3 jaw chuck so it is a friction fit in the larger tube.  Doing this shops the smaller tube moving into the larger tube while soldering.  The sleeves made were then soldered into the plug making sure that they are fitted the right way around with the soldered tube on the outside!   























More to come.

Regards Tony.


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## Tony Bird (Oct 16, 2012)

Hello again,

Having a bit of a problem with Photobucket so doing it in sections.

With such a small burner commercial gas jets as supplied are too large so have to be altered.  If a threaded bush has been fitted in the sleeve they can be made to screw in as on my test rig.  Or as in the case of the sleeves made a slide fit.  The test rig one is screwed for safety as during tests it would be easy to pull out.  Most of my burner jets fitted to models are a slide fit it makes them easier to take out if a jet blocks, thay are held in place by copper pipes not silicon tube as used on the test rig.  Photograph shows a jet as bought and altered to either a screw or a slide fit.






Regards Tony.


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## Tony Bird (Oct 16, 2012)

Hi,

To finish describing what was completed yesterday.

Creating the air hole in the sleeve, the soldered brass is very soft so it has to be carefully done.  First a round file was used across the sleeve to create a flat section for the drill.  A round not flat file is used as it is easier to get the flat in the correct place also it is easier to lightly centre 'pop'.  A small drill (2mm) was used to create the two air holes.  The holes were increased is size by either using a round file or a tappered broach, I used both.  The raised ridge created by opening the holes both inside and outside of the sleeve were removed with a fine file, this helps smooth the air flow into the burner.  The photographs show the effect of increasing the size of the air holes from the 2mm drill hole to 4.3mm when the gas/air mix is OK.  The burner was then checked working inverted in the boiler and then with a smaller poker fitted.  This pug will now be capable of supplying the correst gas/air mix to most burners that can be fitted into it.















































Five more to do today!


Regards Tony.


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## Tony Bird (Oct 16, 2012)

Hi,

Unless there are any questions it looks like it is the end of this thread.  Today finished the six plugs and fitted some of them with pokers and put them in the three boilers that are finished.











I now have to make the rest of the fittings for the boilers.  Goodall water top-up valves have already been made and fitted so it is safety valves, water gauges, regulators and save up for some pressure gauges.

Hope you enjoyed the thread.

regards Tony.


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## Tony Bird (Oct 17, 2012)

Hi,

Very short video of the control of the burner fitted with short 2 hole poker.





Regards Tony.


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## metal (Oct 17, 2012)

Hi Tony,

Thanks for the very useful pictures. Once I'll get a lathe again I'll certainly use them!

Some remarks: at the first (?) page you refrain from the use of cross tubes because of turbulence, however heat transport improves with turbulence. I would advise to make the crosstubes out of solid in order to have enough wall thickness and choose the steam pickup point carefully (avoid too wet steam).
Further: when I'm making a flue with cross tubes I do the hydraulic test on the flue only first, so I'm sure it is sound before soldering it in the boiler (which is necessary with my solder skills ).

Further I was wondering if you are aware of the concept of a radiant poker burner, as can be seen here: http://www.southernsteamtrains.com/notes/radiantpokerburners.htm. These burners seem to be more efficient compared to the default blue flame poker burners. 

Cheers,


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## Tony Bird (Oct 18, 2012)

Hi,

*Some remarks: at the first (?) page you refrain from the use of cross tubes because of turbulence, however heat transport improves with turbulence. I would advise to make the crosstubes out of solid in order to have enough wall thickness and choose the steam pickup point carefully (avoid too wet steam).*

I'm sorry I didn't make myself clear.  I didn't use cross tubes as they would have had a very small hole through them about 1.6mm (1/16"ish) apprantly according to the late Colin Binnie these small tubes would work like 'pop-pop' engines and create a lot of turbulence.  I haven't prooved this myself but it seems logical.  Certainly convection currents in a boiler are a good thing but not too much turbulence.  When steam is released from a boiler there is a certain amount of turbulence in the area of collection hence steam domes or perforated pipes fitted to the top of the inside of the boiler.  The boilers described have their regulators on the top because of no steam dome being fitted. 

*Further: when I'm making a flue with cross tubes I do the hydraulic test on the flue only first, so I'm sure it is sound before soldering it in the boiler (which is necessary with my solder skills 
	

	
	
		
		

		
		
	


	




).*

I usually do the same but I don't have a rig for such a small tube and as it might well have been a one off, I relied on a good visual check.  As a horizonal boiler using a 15mm flue tube is being made some plugs will be made so that the flue can be pressurised from its inside.


*Further I was wondering if you are aware of the concept of a radiant poker burner, as can be seen here: **http://www.southernsteamtrains.com/notes/radiantpokerburners.htm**. These burners seem to be more efficient compared to the default blue flame poker burners.*

Yes they are but I don't know of a design that will work in a tube with an ID of 13.5mm.  If there is such a design I would be very interested in it.  Photograph shows a radient burner designed to fit under a pot boiler.









Last evening the boiler fitted with cross rods was used to power an Accucraft Ruby chassis which it did easily.  The boiler with no cross rods only managed to turn the chassis over continuously at very low speed.  So a small diameter boiler using cross rods will be made for the Ruby also a pressure test rig for the flue will be made.

Regards Tony.


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## Tony Bird (Oct 19, 2012)

Hi,

Test rig made to check 15mm flue tube of boiler to be made.  As the fitting of cross rods seems to improve a boilers performance it was worth making a test rig.













The flue fits over a plug to centre it and seals on a fibre washer, the test pressure is the same as the boiler 120psi for a working pressure of 60psi.

Regards Tony.


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## exairman (Feb 27, 2013)

Hi I am building a Darj & Him class B the boiler is 42mm od by 200mm long and has flue tube 18mm od it  is more or less a copy of Keith Bucklitch,s design with the raised fire box. I bought gas burner from Roundhouse but on testing  it in the boiler the flame shot through to the smoke box threatening to set every thing alight within it,s vicinity(wife not impressed I was using the potting shed table at the time). Could it be that the flue tube is too small for the poker dia0.375"? Perhaps my boiler is too long for this burner?.I was very interested in the idea of inverting the burner as with such a small diameter boiler with a fairley large flue tube there is not a great deal of water coverage above the flue tube. Grateful for any advice on this problem . Regards


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## Tony Bird (Feb 28, 2013)

Hi,

Welcome to HMEM.

*Hi I am building a Darj & Him class B the boiler is 42mm od by 200mm long and has flue tube 18mm od it  is more or less a copy of Keith Bucklitch,s design with the raised fire box. I bought gas burner from Roundhouse but on testing  it in the boiler the flame shot through to the smoke box threatening to set every thing alight within it,s vicinity(wife not impressed I was using the potting shed table at the time). Could it be that the flue tube is too small for the poker dia0.375"? Perhaps my boiler is too long for this burner?.I was very interested in the idea of inverting the burner as with such a small diameter boiler with a fairley large flue tube there is not a great deal of water coverage above the flue tube. Grateful for any advice on this problem . Regards* 

I am not familier with the Roundhouse poker burner but I will try and help.  It could be any or a combination of all your suggestions.  A couple of questions;

Does the burner work well out of the flue and does the gas valve allow small adjustments to the flame?

As the gas is turned up does it blow the flame out?

Is it possible to see a photograph of the burner lit?

Regards Tony.


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## exairman (Mar 1, 2013)

Hi Tony many thanks for your kind assistance l have tried to send you some pics but l suspect they won,t go. Got the wife a tablet for Christmas and l am using that as the regular is not talking to me anymore. I have real idea how down load the photos and  l have found the forum rather difficult. So l don,t know if they have gone or not. Hope to from you shortly Best  Wishes


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## Tony Bird (Mar 2, 2013)

Hi,

Alas no photographs or PM's.

Does the burner work well out of the flue and does the gas valve allow small adjustments to the flame?

As the gas is turned up does it blow the flame out?

If the flame outside the flue tube burns well and is controlable then the burner is possibly too large in diameter for the flue.

See if you can manage to post the photographs.

Regards Tony.


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## exairman (Mar 8, 2013)

Hi sorry to be a pain but l am having troubles find my way around this forum. I did try and send some pics but they must have gone into hyper space or some thing so l shall try again. When the valve is cracked open the flame evenly displaced but as the valve is gradually fully opened the flame moves along the poker and eventually forms a triangular shape the base being about  half the length of tube from the end.lt would appear that the gas at the jet end is not igniting until it meets the flame at the aft end. If l can get the pics to you it will probably be lot easier to understand than my ramblings. Just tried again l still don,t seem to be able to attach the photos l gone through the relevant instructions but to no avail just hope you can make sense of my text. Regards.


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## Tony Bird (Mar 9, 2013)

Hi,

*When the valve is cracked open the flame evenly displaced but as the valve is gradually fully opened the flame moves along the poker and eventually forms a triangular shape the base being about  half the length of tube from the end.lt would appear that the gas at the jet end is not igniting until it meets the flame at the aft end.*

The valve does not have to be opened full, it is often the case that the flame will blow out if the valve is opened beyond a certain point.  A smaller jet or a valve with a smaller delivery hole using a needle like the jet in a carburator can reduce this effect.  But this might not be the answer.

Regards Tony.


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## joeb (Jan 20, 2014)

Just read the thread - very informative thanks 
I am about to do a refurb on a Cornish boiler that I got on ebay 
I started a post on it before I read this (search is your friend) and it does not have a burner 
the boiler has cross pipes in the burner tube that start about 50mm to 60mm in which would block the type of burner your using 
any ideas on what sort of design I could use 
Cheers
Joe


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## Tony Bird (Jan 24, 2014)

Hi Joe,

*Just read the thread - very informative thanks.  I am about to do a refurb on a Cornish boiler that I got on ebay.  I started a post on it before I read this (search is your friend) and it does not have a burner.  The boiler has cross pipes in the burner tube that start about 50mm to 60mm in which would block the type of burner your using, any ideas on what sort of design I could use.*

 If it is an old boiler it might well have used a blow-lamp type burner.  What size is the flue tube and the over-all size of the boiler?  I will try and find your thread.  I am away in a warm country which has power cuts using a very slow computer in a foreign language. but back in the UK next week sometime.

 Regards Tony.


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## Tony Bird (Jan 29, 2014)

Hi Joe,

*Just read the thread - very informative thanks. I am about to do a refurb on a Cornish boiler that I got on ebay. I started a post on it before I read this (search is your friend) and it does not have a burner. The boiler has cross pipes in the burner tube that start about 50mm to 60mm in which would block the type of burner your using, any ideas on what sort of design I could use.

*If it is an old boiler it might well have used a blow-lamp type burner. What size is the flue tube and the over-all size of the boiler? I will try and find your thread. I am away in a warm country which has power cuts using a very slow computer in a foreign language. but back in the UK next week sometime.



 Back in the UK.  A lot colder and damper but the computers are reliable!

 I have found your thread on the boiler.  From the photographs the flue looks about 35mm ID?  A suitable burner might be a ceramic plug type.  I have never made one but have a friend who has made many successful ones that produce a lot of heat.  I think that several companies that make model boilers in the UK can supply some.  If you like I will contact my friend and see what he thinks.

 Regards Tony.


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## PomyMark (Jul 9, 2019)

Tony Bird said:


> Hi,
> 
> *very nice would like to know more about the burner *
> 
> ...


Hi tony have to make one for a boiler I have do you have any more details on how you did the gas jet


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## PomyMark (Jul 9, 2019)

Tony Bird said:


> Hi,
> 
> *very nice would like to know more about the burner *
> 
> ...


Hi tony have to make one for a boiler I have do you have any more details on how you did the gas jet


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## Tony Bird (Jul 9, 2019)

Hi Mark,

Do you have any more details on how you did the gas jet?

Not sure what you mean.  The burners shown are using a commercially made gas jet No.3 which I think has a 0.15 mm hole, when designing a new burner I start with the smallest which is a No.3 and work my way up in size until I am happy with the results.  Hopefully this might be the answer if not expand the question and I will do my best to answer.  In the attached video the small model locomotives that are running a little fast use the burner described in the thread.



Take care.

Tony.


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## PomyMark (Jul 10, 2019)

That is what I was after did you get that from Bunnings


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## Tony Bird (Jul 10, 2019)

Hi Mark,

*That is what I was after did you get that from Bunning.*

Sorry I don't know who Bunning is, are they in the UK?  I probably got the jet from 'Chuffed to Bits' a steam model supplier here.

Take care.

Tony.


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## PomyMark (Jul 10, 2019)

Sorry I thought you was in Australia


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## rickhann (Jul 10, 2019)

I am coming into this discussion a bit late, but I may be able to add a bit.  I worked for several years developing a propane burner for my 3-1/2" Rob Roy.  I found a spread sheet calculator that calculated BTU output for a burner by entering orifice size, gas pressure, & orifice coefficient.  It can be found @ https://ronreil.abana.org/BTU_Calculator.xls   You must download and open the file.  As for burner jets, I use misting nozzles.  They are cheap.  You can get  20 for $10 on eBay (.3mm/.024").  If you need smaller ones, aeromist.com has smaller ones (.008" and .012") for a couple dollars each.  If you have a set of number drills, you can modify existing opening to whatever size you need.  Have fun playing with the BTU calculator.  Hope this adds to the discussion.
Rick


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## peter2uat (Jul 10, 2019)

When we got our new cooking hob (for natural gas) there was a extra small bag with four no. 3 nozzles included -  they are for propane gas - perfect for the next boiler. Thread is M6x0.75. I think most people just throw them away as those nozzles are of no use for them. Just ask around when someone gets his new kitchen...


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## Steamchick (Feb 8, 2021)

Hi All,
I'm curious about the burners you make for these little locos. Personally, I am not a G1 enthusiast so have no locos. But I have made many ceramic burners and a few "blow-torch" type burners, and a couple of pipe burners. In terms of the theory, there seems to be a total lack of it everywhere, but having scoured the interweb found some papers from neraly 100 years ago - which do a lot of empirical analysis and develop some odd general rules for burners. (I like theory - if I can find something I understand!).
I have seen the various web discussions about pipe burners - and the mertits of radiant heating by use of a gauze "tent" - or other description for a gauze in the hot part of the flame.
A few "standards" I find useful, that may help anyone here.

The amount of gas you can push into a burner is dictated by the jet size. There is a finit limit for all jets: Below that limit the amount of gas varies with the square root of pressure, (4 times pressure = double gas). But at the limit (Sonic gas velocity at the jet) you can't get any more gas - the jet cannot pass "super-sonic" gas - no matter how much more pressure is applied. Fortunately, that rarely occurs for G1 burners I guess?
The amount of "fire" you can push into a boiler is determined by the "exhaust volume - and pressure difference to push it". This is difficult to explain, but here goes: For a particular burner and boiler, there is a point where the "fire you push into the boiler" is more than the boiler can take, so it comes back out of the burner hole. (happens on a friend's boiler - with cross-tubes). The way to increase the amount of flame you can stuff into the boiler, is straightforward - assuming you can't increase the cross-sectional area of the "restriction" in the gas flow: (I fitted a bigger chimney on a stationary boiler to allow the use of a bigger burner) - and assuming the blower has been tried to maximum, or engine exhaust blow up the chimney is optimised to the best. The answer is to cool the flame after combustion. The use of a radiant element actually does that. On a 1kW burner, as much as 80% of the heat can be removed as radiant energy - and if you think of this as being like a light bulb - everywhere the radiant can shine will absorb heat - hopefully most radiant heat will shine on the boiler walls and make steam.The cooler gas from the rsidual flames will still pass more heat by conduction to the boiler surfaces, but the gas volume will be smaller, thus reducing the back pressure of getting the gas through the flue tubes.
Ceramics - for durability - need to be quite thick, to avoid overheating the underside of the burner ceramic and causing flash-back when the flame goes inside the burner. (VERY BAD!). So I ensure I have 12 mm of ceramic, 8mm space beneath the ceramic and 10 mm over the ceramic (for flames to complete combustion). so find a ceramic is no good in small tubes - less than 30 mm diameter. The pother issue is that the flat surface of the ceramic prohibits the use of all-round burning and heating inside a fire tube.
On tests with my Cornish stationary boiler (with a 2inch firetube) I found I could happliy use a no 8 jet  on a single sided ceramic. But a blowlamp burner would take a 12 jet (double the gas) so tried a "double sided" ceramic burner. But there wasn't enough space to get the gas-air mixing chamber inside, as well as 2 thicknesses of ceramic, and enough space outside the burner for flames and exhaust. This also became limited to a no 8 jet.  
I made a radial poker-style burner - but the volume of flame limited me to less than a no 8 jet. 
I tried the blow-lamp burner with a cylinder of wire wool inside 2 tubes of wire mesh - This made a full length radiant burner that took a 12 jet and full pressure with no problems. I think I can even use propane at a higher pressure as the flame is so small (exhaust gas volume) when it leaves the wire wool tube.
SO I recommend you try the radiant gauze "tent" over your poker burners, as explained in the Southern Trains stuff - and other chat rooms.
Here endeth my "science lesson"for today.
Happy steaming chaps!
K2


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## Steamchick (Feb 8, 2021)

Here's a picture or 2 of flue tube burners in a Cornish boiler. 
90mm x 10 mm ceramic with 8 jet.










10 x 130 mm with additional radiant coils :









But I decided the Blowlamp burner with surrounding wire wool really increased the power significantly, so that's what I'll run. It takes twice the jet size - so double the gas power - and the radiant is very effective. (but looks scruffy!).

Blow-lamp + wire wool tube in mesh:





Note: The flame - which wpould extend beyond the wire mesh - is cooled by the radiant so effectively it does not exceed the firetube and I can effectively push much more gas combustion into the firetube. All the heat comes out of the burned gas inside the boiler: Mostly as radiant heat into firetube walls - and the rest as hot exhaust for the flue tubes. Maximising the heat exchange by using a lot of radiant increases the performance of the system.

Happy steaming!
K2


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