Making a Simple Ceramic Burner

[KellisRJ]

How do I make ceramic tile or buy. I am from bangladesh.. can any one help me out

I purchased one mail-order sold as a place to solder jewelry. You could also try a lightweight fire brick, they can be cut with a hand-saw and drilled. Water soak it first to prevent dust. You will have to let it air dry or bake it at a low temp to remove the water before you can use it!

 

[Steamchick]

Hi all, an interesting thread. I made my first ceramic burner in the 1990s for my father's 3" horizontal bench boiler, with a second- hand plaque from a scrapped gas fire. Still good, I used it earlier this week for an hour. I have made many burners and have been tying to find some real engineering information on jet sizes, air hole sizes, mixer tube sizes, diffuser designs and sizes, burner hole CSA, and finally burner power. Sadly, almost nothing! So I have been trying to collate information and develop something. I use a design of "calculated" diffuser, and seem to be getting it right almost every time now. But it isn't finalised yet. It really needs someone with gas-flow software to optimise on a computer. The turbulence in a burner cavity is at a very low pressure, with a very rapid exchange of momentum to pressure of the mixed gas, and the turbulence causes the varying colours of red to be seen on burner surfaces. When introduced into a confined space of a firebox, the pressures change and the whole thing is affected. So far my smallest burner is about 2sq.cm., and the largest 7 1/2 x 5 inches. (Sorry to mix dimensions, but I was brought-up "bi-dimensional"!).
Any actual engineering calculations or links will be appreciated.
Thanks,
Steamchick

 

[Tony Bird]

Hi,

Sorry I have no knowledge of gas dynamics I just play with a reasonable amount of success.

Take care stay safe.

Tony.

 

[TSutrina]

FreeCAD, yes zero cost, is a design software where you can model the burner. It has a work bench that allows you to do finite element. I have not used it but part of that work bench is a fluid flow analysis. I do not know if in includes burning where temperature and gas properties change. I suspect it doesn't.

 

[BobsModels]

I built one of these for my 2" Rider Ericsson Hot Air Engine. Its about .75" OD and been working real well for the last 5 years, uses a flat fairly hard flat surface ceramic that I had been using for silver brazing. I just used a hole saw to cut it out. I use propane at about 1 to 1.5 psi. I basically redesigned it from drawings by Sandy Campbell.

I attached a set of drawings for it in PDF.

Bob

Rider Ericsson Burner Only.pdf

 

[doubletop]

I have made many burners and have been tying to find some real engineering information on jet sizes, air hole sizes, mixer tube sizes, diffuser designs and sizes, burner hole CSA, and finally burner power.
Thanks,
Steamchick

Its been a while for me and had to re-research dead links but try these as a start


http://www.joppaglass.com/burner/lowp_chrt.html

http://www.joppaglass.com/burner/highp_chart.html

Computational studies of fuel and air mixing characteristics of a low pressure domestic gas appliance - Universiti Teknologi Malaysia Institutional Repository

Pete

 

[Steamchick]

Brilliant! I'll study this lot and see how it marries with previous knowledge. A par from around 2000 from St, Marys college in Llondon, and a US Dept of commerce paper from 19220 gave some clues but mot he whole dtory. Big gaps, and things that don't work , plague this bit of knowledge . Probably why so many people "play about and make something work", but do do any real Engineering...
I feel that while many copy existing designs, there is the "real Engineering" where something is designed and works well first-time, and I haven't yet found the Engineer who has this knowledge. Hopefully that is Pete?

 

[Steamchick]

Sorry for typos. For "do do" read "don't do". Spell checker doesn"t like my grammar.

 

[rickhann]

This may help. jresv8n6p669_A2b.pdf An old research paper, but some good info.
Rick

 

[rickhann]

Here is another research paper. nbstechnologicpaperT193.pdf
I used information from both of these papers (see previous post) to develop my ceramic burner for my Rob Roy. I took basic principles i.e. burner throat area ratios, distance from jet to throat, throat to burner distance, taper of burner tube, recommended port areas per BTU. I knew how many BTU's were needed and worked backwards to come up with the basic dimensions. Because of limited space, I could not follow the recommended ratios and dimensions exactly, but tried to get the as close as space allowed. It took me a couple years, but I ended up with a propane ceramic burner that provided more than enough heat to run my Rob Roy. If interested, I have a video on u-tube. Rick's Rob Roy

 

[Steamchick]

Thanks Rick. Yes, I have studied this paper. It's not all "outdated" as these gas rings with injectors (I would call them venturis) throat lengths etc. work pretty well. But I still find every configuration and size of burner I make deviates - and in different ways! Most confusing!
Thanks for the link anyway. I'd like to see the Rob Roy and burner.

 

[doubletop]

My thread on my work on my Rob Roy burner https://www.homemodelenginemachinist.com/threads/ceramic-gas-burners-on-locos.10137/

Expert, I'm afraid not. Like you I employed an emprical approach and then realised there should be some engineering/science behind all this so went looking for information.

Pete

 

[rickhann]

Thanks Rick. Yes, I have studied this paper. It's not all "outdated" as these gas rings with injectors (I would call them venturis) throat lengths etc. work pretty well. But I still find every configuration and size of burner I make deviates - and in different ways! Most confusing!
Thanks for the link anyway. I'd like to see the Rob Roy and burner.

The first picture is of a burner I made that gave me hope of success. My previous attempts only had one venturi tube. As you can see, this burner has two. I actually had a successful run with this burner, but when I got home and looked, I realized I had to make it more heat resistant. Even though the burner destroyed itself, it put out plenty of BTU's (Estimated output north of 16,000 BTU's) .The 2nd and 3rd pictures are of a stainless steel burner box. As for the use of two burner tubes, I did some rudimentary calculations and found that the ceramic element had enough capacity to provide the required BTU output, however the single venturi tube would not provide enough gas, therefore I added the second venturi tube. I gleaned from another source that once the velocity of the gas through the jet reaches the speed of sound, increasing the pressure will not increase output. I did a rough calculation and found that my single venturi would would only provide around 12,000 BTU's. This will run the Rob Roy, but only marginally. As an aside, I relied heavily on the work doubletop had previously done. You can see a video of my engine running by going to u-tube and entering Rick's Rob Roy

 

[doubletop]

Rick

I had a look at your video, Impressive and, as you say more than enough steam produced. I had come to the conclusion I was producing about 12000BTU's so it would seem we are both in the same ball park with our calculations.

Regards

Pete

 

[Steamchick]

Thanks Pete. I have done some crude calcs and realise the bigger mixer tubes allow bigger jets. Simple as that. I think that basically it is easy to over-fuel a small mixer tube, so without enough air, the combustion is poor and not complete. With balanced chambers and connection areas, max fuel gas gets the correct air and max heat results. But this can burn-out ceramics. I want a thermometer, as a Chinese special says 1200 degrees C max. I have had ceramics white hot! But they cracking and fall apart upon cooling, or flask back. Too much fuel an air. Keep up the good work. Your info is helpful.

 

[Steamchick]

Should read "Chinese specification" - but google re-writes half of my typed words. Wonderful technology? Not if you are literate!

 

[Steamchick]

PETE: is that 12000 BTU/hour? What do you reckon that is in wattage? I have a conversion 1 kW = 34121 BTU/hr. But I am not sure? Maybe there is a decimal point missing?

 

[BWMSBLDR1]

Drop the trailing 1 and you are there! Bill in Boulder CO USA

 

[Steamchick]

Thanks, It did seem that I was using a factor 10 times to big. But the conversion on the Internet put me right and agrees with you. (I think I must have copied the factor I previously researched using my "random hand" - it doesn't always write properly! - Always blame the tools - the brain is perfect, isn't it?).

 

[smittman]

Keith Appleton has slot of help videos on you tube this one deals with setting up ceramic burners and self destruction it might help looking at.