Turbulator - easy cheap DIY

[jebatty]

I apologize if this happens to be repetitive, but these DIY turbulators were so easy and inexpensive that I had to pass it around. This should work for all boilers with vertical heat exchanger tubes.

I have a Tarm Solo Plus 40. Has 8 hx tubes of 3" diameter and about 29" long. I had an old 1/2" link chain. I cut this into 8 29" lengths. I then took a 20d nail (about 1/4" diameter), inserted it through the top link, dropped the chain down a tube, using the nail to bridge the top of the tube and hold the chain in the middle of the tube. Repeat 8 times.

Fire the boiler. Observe stack temp drop by 100F more or less. One website claims a 1% increase in boiler efficiency for each 40F drop in stack temp. Thus, 2-1/2% increase in efficiency.

Cost to me: $0 -- all old, used items around the house.

If anyone knows of a safety issue or danger in this setup, please advise.

Happy New Year!

 

[Reggie Dunlap]

I wish I'd thought of that before I paid $180 for mine.

Reggie

 

[Bartman]

My New Yorker WC-120 had twisted steel turbulators, the same as theirs and other makes oil boiler turbulators for 2" fire tubes. Years ago I yanked them out due to them plugging up. Since my boiler dosen't run full bore all the time this was a problem. Periodic checking of them would certainly be advised.

 

[barnartist]

I used some 1/2 thick rods with welded washers every 6 inched or so. This might be ok for full boar fire, but they do collect debris if idleing alot.
Now I have made some spirals, which work better, definately 100 degree drop in flu. Had a welding guy slice me some sheet metal, mounted two vises on a table, then used an oversized cresent wrench by turning it in the middle of the metal. Be sure to get the width smaller than you think though, mine have to be forced in and out.
Its worth the time.
That chain idea sounds great though.

 

[rcollman]

How do the turbolators work?

The name seems to say they mix up the air flow, so the hot air does not stream in some sort of stratus formation, with a hot column in the center? That must be it. It is not so much that the turb blocks the flow, as distruts the laminar flow (think that is the word).

I was looking at 236 sq inches in the tubes and 113 inches in the stack and trying to figure that out

-21 at 4 and the cars started and two day in a row of almost 80 HHDs. Geeez, I better start pulling on my go to meeting dress clothes for a day downstate at work.

Stay warm

 

[jebatty]

You've got how they work, and they do work. Mine have been in operation for a little over a year now. Bottom link or two are white-grey in color, and the rest are dark grey to black. It gets hot at the bottom of the hx tubes. No evidence of chain deterioration other than color change.

These were most helpful because I burn a lot of pine slab wood, dry, and that burns very hot. Kept the stack temp down by the 100F +/- mentioned.

 

[free75degrees]

I've been using the chain turbs all winter based on an earlier post by Jim. I don't have any data on the performance improvement, but they were very easy to make and they seem like a no-brainer to me. The best solutions are simple ones like this.

My only customization was that I used 2 threaded rods to hold them in place. The rod goes through the top link of each chain and nuts/washers hold the chains in place. These rods make it a little easier to remove the chains for cleaning because i call pull out 4 at a time.

 

[WoodNotOil]

I plan to do these too, when I get a chance and some extra chain.

 

[Eric Johnson]

I think the chain idea is fantastic: Low cost; effective and easy to do; easy maintenance, and they work!

I would imagine that the chains rattle around some in the tubes as the gas flows by and I wonder if that helps knock some of the crap off of the walls.

 

[chuck172]

"My only customization was that I used 2 threaded rods to hold them in place. The rod goes through the top link of each chain and nuts/washers hold the chains in place. These rods make it a little easier to remove the chains for cleaning because i call pull out 4 at a time."
Good Idea!
Removing the chain turbulators individually is a pain.

 

[jebatty]

The rod idea is good. Actually, I welded the 20p nail to the top link, and it is pretty easy to lift out and put back in. I "rattle" it in the tube before I take it out to knock off the fly ash that sticks to the links.

 

[TimfromPittsburgh]

ANybody installed these chain turbulators in a TArm 502 boiler? How are they working?

 

[Birdman]

Has anyone ever lost a chain turbulator down into the HX tubes? How does one retrieve it? Can you pull it out through the bottom door... like when you clean out the ash?

 

[jebatty]

Whatever falls down an hx tube can be pulled out of the bottom ash area, no problem at all.

 

[barnartist]

Was thinking about this older post, I am thinking of switching to chains myself now because my spiral inserts are a bit too tight and can be hard to get out. Does anyone have anything new to report on using the chains? I have 16 tubes, so i'd like to be sure before I start cutting up some lengths...

 

[jebatty]

Only that I'm now in the third season with my "original" chain turbulators and they continue to perform well. It is important to regularly give them a good shaking or brushing to clean them, also to brush the HX tubes regularly. Very noticeable rise in flue temp as either gets dirty. Flue probe temp rise is a very good clue as to when cleaning is needed.

 

[Huskurdu]

Will using chains be better than using the spiral 'thingys' that came with my Econoburn? How to you clean the turbulators if you remove the existing turbulator 'thingys'? Or is this an apple/oranges type of thing with the different brands of boilers?
np

 

[willworkforwood]

This might be a bit of a thread hijack, and if so I apologize. I have no problem with anything relating to chain turbulators. Everyone using them has great feedback, so they must work very well. But Barnartist's comment about his spiral turbulators being "a bit too tight and can be hard to get out" caused me to send this caution. I just finished an ugly heat tube creosote cleanup job, and getting the turbs out first was VERY hard.
If the turbs were EKO-supplied, or were an add-on (and installed easily), then I would check for creosote buildup in the tubes. Sometimes creosote doesn't show up with a light. Try sending a probe down that can just barely fit in a clean tube - any creosote buildup will stop the probe.

 

[Birdman]

I am repeating a question I had in an earlier post about turbulators.... that did not get answered. Does anyone have data on the correct sizing of the turbulators? What is the correct length? I have the Tarm 40 solo. Second year. LOVE IT. NO storage yet. So.. what happens if I use 22 in chains instead of 29 inch? How do the results change ( efficiency.. or temp of flue ) if the chain is differently sized? How about 31 inch? IF the chains are too long can this have adverse effect on Tarm? How about 15 inches? Does this provide any benefit at this length? Reason being... I have to decide how to cut my limited amount of old skid chains found in my woods ( 2 ) . Do I cut them small.. and install now?... or wait and get some more chain... then cut em longer?

 

[jebatty]

I replied as best as I was able to your prior post, and there is not much I can add to that. I simply cut my chains so that they would not hang out of the bottom of the hx tubes. I experienced about a 100F drop in flue temp as compared to no turbulators. I still run 400-600F with turbulators (very dry wood), with 500F about average. I haven't, and I don't know who has, attempted an experiential or scientific study as to the effect one length has over another. Remember, the idea is to "turbulate" the hot gases, so I would presume that longer is better than shorter, but that hanging below the hx tubes would have no benefit. There exists considerable engineering research on the various shapes of turbulators, so if you want to get into the engineering or science, you can do the research. Make your choice, and then maybe you can be the one to report on the effect, if any, of shorter or longer chain turbulators.

 

[Birdman]

Thanks again for your input. I would like to now let anyone else respond to this concept of the turbulator question. Has anyone out there done this experiment? How does turbulator length effect the efficiency of the Tarm? Does a 22 inch chain do the same thing as a 29 inch chain? And if not... how much less... And if 22 is better.... why ? Sorry to say... I won't be doing the experiment. Guess I will instead.. keep asking questions... in hope that other on this site might have done it already? Or.. that someone who is way better at science and tech will want to take it on? That's why I love this site... so many people on here.. and so smart. I don't have to listen to just one person's opinion..or lack of knowledge... because there may be someone else who has the knowledge.

 

[Gooserider]

Thanks again for your input. I would like to now let anyone else respond to this concept of the turbulator question. Has anyone out there done this experiment? How does turbulator length effect the efficiency of the Tarm? Does a 22 inch chain do the same thing as a 29 inch chain? And if not... how much less... And if 22 is better.... why ? Sorry to say... I won't be doing the experiment. Guess I will instead.. keep asking questions... in hope that other on this site might have done it already? Or.. that someone who is way better at science and tech will want to take it on? That's why I love this site... so many people on here.. and so smart. I don't have to listen to just one person's opinion..or lack of knowledge... because there may be someone else who has the knowledge.

Speculation here on my part, as I don't own a Tarm, and haven't done the experimenting, but I think logic would suggest an answer...

According to the posts I've seen, Tarms have an optimal exhaust temperature, where the smoke is barely hot enough not to condense going up the flue, but has given up all the heat that it can to the water jacket. They control this temperature by putting in or taking out turbulators from the tubes.

Adding turbulators cools the exhaust and transfers more heat to the water jacket.

The turbulator works by slowing the smoke flow so you have longer "residence time" for heat transfer to take place, and increased turbulence for greater contact with the tube walls.

My assumption, is that given a single tube, the longer the turbulator, the greater the impact that it would have just because it made the turbulence greater.

I would also think that if you had multiple tubes, the effect would be better if all tubes had the same length, short, turbulator as opposed to some tubes having a long one and others having none. With all tubes having the same length, then the exhaust should flow equally through all the tubes since all would have the same resistance. If some tubes had turbulators and others didn't, then the ones without would have lower flow resistance and therefore would see much more flow than the ones with.

Thus my conclusion would be that the optimal solution would be if all tubes had turbulators of the same size and length, with the length chosen to produce the optimal exhaust temperature for that installation.

That said, I don't have any real good ideas on how to predetermine what that optimal length should be - I'm sure there are fluid dynamics formulas that would tell you, but I don't know what they are or how to apply them, and I would note that many of the equations I've seen have involved some very hairy and complex math....

Experimentally I'd see two ways to go - Start with full length turbulators in all tubes, measure the temps, and shorten all of them by uniform amounts until it works. Or start with empty tubes, add full length turbulators a few at a time till you get to the working temperature, and then calculate an average length, put those in and go back to the first method. Given that it is generally easier to make chains or metal strips shorter rather than longer, I'd probably start with the first method...

Gooserider

 

[jebatty]

Good ideas, but many incredibly complex variables: the wood species, dryness, length, size of splits, how it's loaded in the firebox, how full the firebox is, the rate of burn, the exact setting of the draft control on the blower, chimney draft, wind conditions, obstructions, outside temp, temp of combustion air, humidity inside and outside, temp of water, water flow rate, how clean the hx tubes are, and probably more, including the size of the chain itself.

Based on my experience and with all the above variables, I was running 600 and up to 900F probe flue temp initially (3 seasons ago). After damping down the draft fan and adding the chain turbulators, which are the length of the hx tubes (if I had kept one more link they would have hung below the hx tubes), I now run 400-600F probe flue temp, with a pretty consistent burn in the 500Farea. When I experienced the high probe flue temps, I called Bioheat (it's predecessor) and was advised that "most Tarm users see probe flue temp of about 600F."

With the chain turbulators, I also know that with probe flue temp of 400Fit is impossible for me to get the rated 140k btu output from the Tarm, except at delta-t of about 90-100F. At 500-600F probe flue temp I can achieve the rated output at a much less delta-t. I also know that the chain turbulators plus the adjustment in the draft fan damper resulted in a 100F+ drop in probe flue temp. I measure output with a flowmeter (gpm x 500 x delta-t). The flowmeter itself is not super-accurate, so my measurements are not precise but do give a good relative read on boiler performance.

I know some, perhaps with Tarm and certainly with other brands, see lower flue temps. The variables I am stuck with are my wood, which mostly is pine, pine slabs, or aspen, all of which is very dry and fast, hot burning wood, and my chimney with the draft it produces. If I had oak, hickory, hard maple, etc., to burn, my experience may be much different.

I think an exercise with turbulator performance would be interesting, but not very helpful, except to the one doing the exercise, due to the great many variables and inability to do controlled experiments. There are engineering literature and data available on performance of different configurations of turbulators, but the literature I saw did not test the carefully crafted and highly engineered "chain" turbulators.

Everything aside, it appears to me that most, if not all, of the downdraft gasification boilers with firetube heat exchangers will benefit from turbulators, regardless of configuration. The chain turbulators are easy to make and install (in some boilers), cheap, hardy, easy to clean, and they perform. For me, it's a no-brainer to use them or a different type of turbulator of choice. The caveat is to make sure with turbulators flue temp is not so low as to cause condensation of combustion gases.

 

[Birdman]

So help me again with my thoughts. What if my flue temp goes too low when using 8... 29 inch turbs? Would I thus try to use 8... 22 inch turbs? Or.. do I use 4... 29 inch turbs? And... sorry.. this all new to me.... I want my flue temp to be no lower than 500?

 

[Birdman]

Sorry... Gooserider.... I just read your post over again. That last paragraph explains it. I will try your ideas.