Small Gas Poker Burner

Discussion in 'Boilers' started by Tony Bird, Sep 19, 2012.

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  1. Sep 19, 2012 #1

    Tony Bird

    Tony Bird

    Tony Bird

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    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.
    [​IMG]
    Comparative drawing.
    [​IMG]
    Testing copy boiler.
    [​IMG]
     
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  2. Sep 19, 2012 #2

    Tony Bird

    Tony Bird

    Tony Bird

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    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.


    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
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  3. Sep 20, 2012 #3

    Tony Bird

    Tony Bird

    Tony Bird

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    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.
    [​IMG]

    Second pressure gauge used.
    [​IMG]

    Smaller chimney tried.
    [​IMG]

    10 slot burner.
    [​IMG]

    Video
    [​IMG]

    Boiler lagged.
    [​IMG]


    Regards Tony.
     
  4. Sep 20, 2012 #4

    Tony Bird

    Tony Bird

    Tony Bird

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    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.


    [​IMG]
    Underside of ceramic burner which is sealed to the boiler no secondary air needed.
    [​IMG]
    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.
    [​IMG]
    Checking the ceramic burner used.
    [​IMG]
    Cross rods and extended flue.
    [​IMG]


    Regards Tony.
     
  5. Sep 20, 2012 #5

    Tony Bird

    Tony Bird

    Tony Bird

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    Hi,

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

    Six cross rods soldered through flue tube.
    [​IMG]
    Checking it is possible to light the burner which is sealed into the flue tube.
    [​IMG]
    Futher test to see if the burner can be lit from the top of the chimney. Note the burner is inverted.
    [​IMG]

    [​IMG]
    Flue in boiler to check clearances.
    [​IMG]
    Main parts of boiler.
    [​IMG]

    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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  6. Sep 22, 2012 #6

    Diversion900

    Diversion900

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

    Cheers, Neil
     
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  7. Sep 22, 2012 #7

    gus

    gus

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    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.

    GAS FIRED VEE ENGINE 1.jpg
     
    Last edited: Sep 22, 2012
  8. Sep 22, 2012 #8

    Tony Bird

    Tony Bird

    Tony Bird

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    Hi,

    Well yesterday morning the boiler came out of the pickle and looked a lot better.
    [​IMG]


    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.
    [​IMG]
     
  9. Sep 22, 2012 #9

    Tony Bird

    Tony Bird

    Tony Bird

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    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.
     
  10. Sep 22, 2012 #10

    Tony Bird

    Tony Bird

    Tony Bird

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    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!

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    With a 6 inch ruler to show size
    [​IMG]

    Regards Tony.
     
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  11. Sep 25, 2012 #11

    Diversion900

    Diversion900

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    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
     
  12. Sep 26, 2012 #12

    gus

    gus

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    Please enlighten Gus.What is VHT paint and where I buy them??
     
  13. Sep 26, 2012 #13

    Cogsy

    Cogsy

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    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.
     
  14. Oct 8, 2012 #14

    Tony Bird

    Tony Bird

    Tony Bird

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    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.




     
  15. Oct 9, 2012 #15

    Tony Bird

    Tony Bird

    Tony Bird

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    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.

    Poker burner 10 slot close up   LR.jpg

    039 10 rod flue LR.jpg

    040 10 rod flue test LR.jpg
     
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  16. Oct 13, 2012 #16

    Tony Bird

    Tony Bird

    Tony Bird

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    Hi,

    [​IMG]

    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.

    [​IMG]

    Regards Tony
     
  17. Oct 14, 2012 #17

    Tony Bird

    Tony Bird

    Tony Bird

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    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.

    [​IMG]
    First filled with a piece of wooden dowel then marked out.

    [​IMG]
    Pilot drilled then opened to finished size.

    [​IMG]
    Drilling finished.

    [​IMG]
    Wood drilled out.

    [​IMG]
    Drilling completed.

    [​IMG]
    End crimped.

    [​IMG]
    Other end slightly deformed to create friction fit.

    [​IMG]
    Completed poker part of the burner.

    [​IMG]
    Fitted with mesh.

    [​IMG]
    Test.

    [​IMG]
    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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  18. Oct 14, 2012 #18

    steam58

    steam58

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    hi
    very nice
    would like to know more about the burner
     
  19. Oct 15, 2012 #19

    gus

    gus

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    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.
     
  20. Oct 15, 2012 #20

    Tony Bird

    Tony Bird

    Tony Bird

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    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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