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Recirculation burner

Posted by Caleb Ramsby 
Recirculation burner
January 05, 2009 05:53PM
This is the recirculating burner that I mentioned a while back, finally got the scanner running.

Caleb Ramsby

Re: Recirculation burner
January 05, 2009 05:54PM
Lets try that again.

Re: Recirculation burner
January 05, 2009 06:02PM
I have croped the original advertisement into three different sections, it won't appear to allow me to upload the larger file size.

Re: Recirculation burner
January 05, 2009 06:02PM
Photo of burner

Re: Recirculation burner
January 05, 2009 06:03PM
Text that went along with the above.

Re: Recirculation burner
January 05, 2009 06:17PM
Looks like a first generation blue flame burner used in lot of small foundries.

Re: Recirculation burner
January 05, 2009 06:35PM

As best as I can tell this was from around the mid 1950's or so.

It was made by Thermal Research and Engineering Corp. out of Conshohocken, Pennsylvania.

The following is a caption that was bellow the drawing.

"THERMAL High Velocity Oil Burners for distillate oils (thru #3) are availiable in seven standard models with outputs from 50,000 btu/hr to 4,000,000 btu/hr."

I believe that if one were to combine a recirculation burner with a whistle type ultrasonic atomizer one would have one heck of a burner. Actually I don't know if the ultrasonic atomizer would make that big of a difference or not, but I can't see how making the fuel drops smaller before entry into the recirculation area would hurt the performance of the burner.

A tiny positive displacement air pump(to provide air for the whistle type ultrasonic atomizer), about the size of a lighter plug in automobile tire pump, operated by a motor which also drives a fan for the primary air would make a nifty setup. This would be much easier to do with a single firing rate.

For a variable firing rate the use of a carb that mixes the air and fuel well up stream of the burner would also work great, then one could use the Doble type exhaust steam driven fan to jam the speed way up and increase the output of the burner.

One thing that I really like about this burner design is that the center tube section, designed to have an air velocity greater then the flame propagation velocity virtually eliminates flash back. That is if the initial air velocity is kept great enough.

I wonder how far the flame travels out of the burner, if at all.

I bet that this type of burner would also be able to handle coal dust too. . .

Caleb Ramsby

Edited 1 time(s). Last edit at 01/05/2009 06:37PM by Caleb Ramsby.
Re: Recirculation burner
January 05, 2009 07:53PM
Hi Caleb,

I had no trouble with the first .jpg

10,000,000 BTU/ ft^3 is a compact burner. I noted that the recirculating air from the flame is coming from the entrance end of the flame and in the blue flame burner it is taken from the exit end of the flame.

It said that the exiting flame is non luminous which would indicate that combustion is complete inside the burner. This would then be very fast combustion and should lower the NOX products some.

Wouldn't an adjustable nozzle and venturi work with this concept to get a high turn down ratio?

Best Regards, ---- Bill G.
Re: Recirculation burner
January 05, 2009 08:14PM

Weird, I couldn't open up the original file after uploading it. . .

Compact indead! The only burners that I know of that approached this fire density were the Velox type. There are others I am sure, I am just ignorant of their existance.

I never thought of an adjustable nozzle for it, sure sounds like it would work.

Note also that the incoming air goes around the outer half of the burner casing, thusly being preheated slightly and cooling down the burner.

I havn't seen a lot of recirculation burners that appear to recirculate as much of the flame as this one does.

I have found some company's that make the ultrasonic type of atomizers that I was talking about.

Here is a great article on what is occuring producing the small droplet/particle size after going through an ultrasonic atomizer, both liquid atomization and solid particle(coal dust etc.) dissentegration.


The following is from Sun Combustion, Inc.

Firstly their atomizer, which can handle an oil and coal dust slurry.


Here is their liquid fuel pilot system.


This is a more standard air atomizing nozzle system, non ultrasonic,


Some really interesting products here, combine the Sun Combustion atomizer, burning a liquid and solid fuel slurry with the recirculation type of burner and holy cow. . .

Caleb Ramsby

Edited 1 time(s). Last edit at 01/05/2009 10:20PM by Caleb Ramsby.
Re: Recirculation burner
January 06, 2009 12:24AM

All your attchments worked. I just know by instinct to hover the mouse arrow by the lower right corner, then right-click.

Got the full size jpg everytime.

To me this seems like a primative EGR system. Granted the technology does work.

Also, was wondering about the group's idea of a 'fluidized solid fuel burner' seems to me the classic text-book description of such a burner uses some form of aggregate, like gravel or pebble rock. This differs from the conventional 'pot-belly' type of burner, no question.

Should a fluidized bed burner encompass something more advanced?


Edited 1 time(s). Last edit at 01/06/2009 12:27AM by Jeremy Holmes.
Re: Recirculation burner
January 06, 2009 03:34AM

This burner is actually a bit more of a flame recirculation burner then an exhaust gas recirculation burner.

The SES burner recirculated the gases that had passed through all of the boiler proper, this one recirculates the gases of the primary flame formation, that is before complete combustion.

The one that Rolly illustrated takes the recirculation gases from nearer the end of the flame.

I have a feeling that if one were to recirculate the gases from both the combustion zone and the exhaust gases one might get the best of both worlds. . .

The most successfull fluidized bed burners that I have seen used volcanic rock as the agragate material. One of the biggest issues with that type of burner is the precipitation of ash in the bed, forming clinkers that sticks the agragate into big chunks. This doesn't happen with all fuels, just the more clinker prone ones. They sure can make a good fire though, it acts like it's own reactor, breaking down the fuel and making a smoke free fire. I have often wondered if they, although burning cleanly, made a lot of CO, hard if not impossible to detect with just the nose and eye.

Caleb Ramsby
Re: Recirculation burner
January 06, 2009 05:05AM
Caleb, Rolly,

Thanks for posting this thread. Looks like an impressive design to me.

Key feature of diagram posted by Rolly that's not disclosed on Caleb's original is feeding fuel in to the recirculation path. I kind of wonder whether it was a feature of the one posted by Caleb, but they weren't shouting about it.

I feel there's little I can add to this, because the message is very clear. I am very excited by this. Like so much, it might be an old & well proven design, but it's new to me. Great for energy density, great for emissions - maybe the radiant power is down a bit, but if you can get enough heat exchanger in the way to produce a cool exhaust, the energy has to go somewhere!

Much appreciated.

Re: Recirculation burner
January 06, 2009 05:15AM

just read your last post. On the CO issue - for liquid fuel you can use a lambda sensor in the exhaust to control the fuel rate. With solid fuel you can add air in down stream to react with CO & make a bit more heat.

Re: Recirculation burner
January 06, 2009 10:11AM

Follow up with this type of burner, as it really is good and as you guessed, an old one. Even some very early jet engine burners used this idea back in the 1940s.

In those Railway Encyclopedias, the one on railcars has a bit on the big ones that International Harvester made. Post mix vaporizing with what looks like recirculation. My personal choice, for what it's worth.
The Coats-French-Staley plumbing diagram for the new version of the Coats car also used this exact type of burner. The car was never made; but the design was superb. Old SACA journal.

At any rate, just for fun I made the venturi type with a small carburetor. Worked perfectly, started up with a white flame and almost instantly went to blue flame.
Good modulation with the carburetor throttle too.

It's also quite easy to use recirculation in a cyclone type of Doble firebox, with a tube inside that does the recirculation using baffles.
All in all, recirculation burners are a good way to go and should be modeled and tested for gaining experience. Easy to do quickly.

As far as the question about NOX, if you keep the flame temperature down below 2500° F with secondary air admission, no NOX.

Re: Recirculation burner
January 06, 2009 02:17PM
Hi Guys,

Now I am wondering something. This type of burner looks like it keeps the luminous flame inside of the combustion chamber.

This then might limit the radiative heat factor and then require more boiler tubing in the convective portion to make up the difference.

I am wondering if an improvement could be made by shaping the combustion chamber spherically and lining it with a refractory material which has a high infrared luminosity. This would form a black body cavity and nearly all of the IR radiation would be projected out the exit hole.

What we get here is that the intensity of the IR output of a given temperature flame is proportional to the distance across the flame. The burner as shown then would emit IR out of the exit proportional to the depth of the flame and the diameter of the exit hole. A cylindrical chamber just bounces the IR back and forth mostly keeping the liner up to temperature but doesn't send the IR out the exit much.

A spherical or similar chamber then can send more of the radiation out the exit and then absorb more IR from the flame to re radiate. Consider every point on the refractory wall to be a point source and design for the minimum number of re-absorptions and re-radiations to get out the exit hole.

Every time we can knock down the above number the refractory can absorb more IR from the flame and the radiation factor from the burner increases. If for instance the average number of re-absorptions and re-radiations until exit is six and we knock it down to three, by reshaping the chamber, then the amount of IR exiting the burner has doubled.

Best Regards, ---- Bill G.
Re: Recirculation burner
January 06, 2009 05:59PM
Doing a bit of web searching on recirculating burners and came accross this company that I had found and lost before.

Their burner is what they describe as "Flameless Oxidation", FLOX for short. Well worth reading their two PDF pages on the subject, I have provided the links bellow as well as their main website.




Their main principle seems to be vigorous recirculation of the burned gases and a very high flame velocity with intimite pre and post mixing.


The burner design that Rolly posted and I posted look rather simular at first but upon closer inspection there are a few big differences.

On the one that Rolly posted, it mainly just uses the later portion of the flame gases to vaporize the liquid fuel prior to mixing with the combustion air.

The one that I posted has a few aspects that are easy to overlook. As I see it there are three significant aspects to this burner.

1: The incoming air is slightly preheated and mixed simultaniously with the fuel and initial flame gases.

2: The HIGH VELOCITY low pressure mixing tube produces a violent and complete admixture of air, fuel and hot exhaust. In this mixing chamber the fuel is broken down into a gas in the presence of the air required for combustion. This is done at a velocity that is too great for flame propagation. Thusly the exiting gases from this tube are intimitly mixed air, fuel and hot partial flame gas that is really ready to burn if it slows down.

3: There is an abrupt and aggressive expansion of the air, fuel(in a gas state) and the hot partial flame gases when the high velocity mixing tube ends. The combustion chamber is necked down at it's outlet, this produces an inner recirculation of the combustion gases in the combustion chamber, this is not illustrated in the drawing but it must occur. The circulation is from the high velocity tube exit in an expanding cone shape towards the exit hole, the restrictive nature of this hole enhances the movement of the gases in a 180 deg reversal back down the walls of the combustion chamber, towards the entrance of the passage for the recirculation gases which are drawn into the entrance of the high velocity mixing tube.

So there is in reality two recirculation zones in this particular burner design.

First, the recirculation of the combustion gases back to the entrance of the high velocity mixing tube.

Secondly, the recirculation of the gases within the combustion chamber due to it's shape and arangement.

To really maximize the benefits of this burner as to boiler usage the addition of significintly preheated air and the recirculation of flue gases(the gases leaving the boiler) with the gases leaving the main combustion chamber in a secondary mixing/secondary reaction chamber would increase the gass mass flow and reduce even greater the CO and NOX.


One could arrange the burner in a vertical possition, replace the ceramic combustion chamber with stainless and wrap it with a coil of boiler tubing. If one were to make a more modular boiler with a few of these burners the turn down ration would be increased even greater. There seems to be as much to say for and against making a bunch of small things as well as just one big thing.

The Crompton Motor Carriage Co. out of Worchester, Mass.(any info Ben?), made from 1903-05 used a four cylinder in line engine(presumebly single acting, such as the Johnson) with 24 vertical fire tube boilers, mounted in two groups on each side of the engine!

Caleb Ramsby
Re: Recirculation burner
January 06, 2009 06:48PM
Another recirculating burner, patent # 3994665

This one also has a gaseous fuel inlet for the combustion chamber, seperate mixing and combustion chambers and a vortex generator section.

Caleb Ramsby
Re: Recirculation burner
January 06, 2009 07:04PM
Hi,,Crompton doesn't ring a bell,,,Worc' was a hotbead of machineshops and ideas,,now in state of,,oh well,,BUT,,if you need a steel rolling mill,,Morgan Co is the place to go,,Steel at the thin end comes out at 84mph+,,,solid carbide rolls,, and plain bearings,,the rollers heat from hydraulic,,,ugh,,omg,,,There was a mill they servaced in Colorado,,Corliss,,24+48 x 36,,as compound it wasn't enough so the engineer set it for simple!!! Steam pistons on the reverse links,,AT FULL SPEED they would reverse it,,BANG,, all 4 cyl saftys would lift,,,Dan Fay said it was like standing next to a cannon muzzle,,Somewhere else in same mill it took 2 men to open a 550v DC knife switch,,one to throw the lever,,,the other to take a corn broom and whack out the arc,,I wonder where they learned the technique,,,hmmm,,I'm still lookin for the sawdust diezel,,The Lanz tractor,,an Clayton-Shuttleworth look like good substitute tho,,but they are not air blast injection,,OOps ,,I ramble again,,If you like slow speed//U/Tube search,,[wichmann,rubb 40hp ] Dont misfire once at low speed,,,now i know why the old timers liked hot tube ign so much,,,similar,,just watch the controls,,,variable prop???,,Ben
Re: Recirculation burner
January 07, 2009 05:25PM
Great stories ben. I have heard of as assistant electrician doing 2 by 4 duty, at the ready to relieve tha main guy from the juices grasp, never heard of the broom arc sweep before! wild stuff

I still think that hot tube ignition could make a come back, one of my favorite types of ignition, not juice required, UFO proof. . .

Caleb Ramsby
Re: Recirculation burner
January 07, 2009 05:45PM

"As far as the question about NOX, if you keep the flame temperature down below 2500° F with secondary air admission, no NOX."

I was wondering about that. Interesting to note.

I like this topic, Caleb, good job.

The very first time I achieved a good jet roar in my burners. I started to think about this type of stuff. Very deep low freq sound almost like a rumbling from down inside. When I first started to observe mach diamonds inside the (my)unit, it made me pause. There is a pretty large spectrim when learning about this topic. Also, I like the way you point out the difference between Rollys burner and the one that your talking about here.

Re: Recirculation burner
January 07, 2009 06:11PM
Something else,

"I started to think about this type of stuff. Very deep low freq sound almost like a rumbling from down inside. When I first started to observe mach diamonds inside the (my)unit, it made me pause. There is a pretty large spectrim when learning about this topic.-Jeremy"

What im loosely refering to here, is, the topic of 'Combustion Dynamics'.


Re: Recirculation burner
January 07, 2009 06:26PM
Check the Compton thread, I posted a link to the engine design.


Re: Recirculation burner
January 07, 2009 06:39PM
Hi Ken,

I followed the link on 'steam engine' of the Compton thread.-edit- C. Crompton ENGINE-

I looked at the first page on the link from paragraph 25 to 30.

The dude is talking about a rotary valve gear to effect cutoff. The thought of such a thing makes me cringe, uuulacck.

I won't even use a ball valve for a throttle, let alone valve gear.

What are you seeing that im missing?

-2nd edit- the thing reminds me more of a (Bosch) diesel injection pump than anything else, the only catch is the diesel pump uses a single event for each channel, not a multiplexed duration for an single event to a single cylinder.-



Edited 2 time(s). Last edit at 01/07/2009 07:19PM by Jeremy Holmes.
Re: Recirculation burner
January 07, 2009 07:56PM
Hi Jeremy:

I wasn't advocating the Crompton engine at all. It was mentioned by Caleb to Bill in an earlier post on this thread and I was just posting a link to a drawing of the engine under discussion. By the description of the vehicle in Horseless age this would appear to be the same engine. Personally, I'm working with poppet valves, looks like far and away the best technology.


Re: Recirculation burner
January 07, 2009 10:59PM
Hi Ken,

I hear what your saying on the poppet valves. I first read about 'pocket-porting' in a book on blueprinting written by Smokey Yunick. I believe it was called 'POWER-SECRETS'.

Here's a link, wait for it to load then scroll down.


Uknow, I spent some time trying to figure out that 'Phase 1 adiabatic engine'. Im still wondering how the 'Grand National Buick turbo' was the inspiration from a high temp engine with ceramic pistons.(un-related)

One thing from the book, other than some theory on how to optimize flow using poppet valves, was Smokey's mention of how a longer connecting rod 'always' seemed to improve low-end torque, all other performance mods being equal.

-edit- as far as I know Smokey did invent the first working flow-bench -



Edited 1 time(s). Last edit at 01/07/2009 11:42PM by Jeremy Holmes.
Re: Recirculation burner
January 07, 2009 11:39PM
Re: Recirculation burner
January 08, 2009 02:21AM
Hi Jeremy,

A pivoting ball valve with port drilled thru ball is a bad idea for a steam throttle; good that you are avoiding it. I have a ball on seat in my throttle that is pushed up by the throttle rod end like a poppet valve. See, I'm using a poppet valve after all. smiling smiley

The poppet only does full shutoff and full opening. Actual throttling is done by a sliding hollow sleeve valve downline, as in the Stanley and Doble throttles. That valve doesn't start to open until the poppet-ball is fully open. This minimizes wiredrawing and erosion through the shutoff poppet. The only wiredrawing through that valve should be a quick whiff of a tiny chunk of steam, only at initial throttle opening, to fill the extremely small sleeve valve bore and (mostly) balance the throttle. Another quick whiff of wiredrawing at throttle closing, depending on how leaky the sleeve valve is.

Re: Recirculation burner
January 08, 2009 06:10AM
As to valves I like the the independent slide type inlet and exhaust valves. Much simpler to make then piston valves often with a smaller clearance volume and as Rolly has said they wear in.

Really though this is one area that I believe is a bit over debated in a way, poppet, piston and slide valves all work and the most important factor seems to be a lack of leakage, which all of them can acquire, some easier and longer then others. As long as enough oil is fed to the engine then the slide valve isn't all that bad, especiall seperate inlet and exhaust ones.

The rotary valve is one of those that is very difficult to get to seal right, I don't think that it is imposible, it would just take very expensive materials and I think LOTS of oil to help seal it. One other thing about the rotary valve is that most of the ones that I have found have a rather small port area.

Caleb Ramsby
Re: Recirculation burner
January 08, 2009 01:35PM

Speaking of valves on the burner thread, anyway.

What I figured out from analyzing my engine was that depending on the high pressure of the inlet steam to negate the effects of a small inlet port area looses efficiency. Many steam engines have a very small inlet and exhaust area compared to an IC engine. I believe this is a mistake for efficiency reasons.

The mechanics of operating a large poppet valve under high steam pressure are difficult though and form a limit as to inlet size. Just as clearance losses are to be avoided so are wire drawing losses. This requires the largest valve area possible and the fastest valve closing action possible. Of course though, a big valve is slower to close, so only about 50 tradeoffs in design here. Not bad for any one element of a new steam engine design.

Best, -- Bill G.
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