Turbulator questions

[Nofossil]

I'm working on getting turbulators, and I have two questions for anyone who has them:

1) About how closely spaced are the twists? If you laid it on a flat surface, what would be the distance between the points where it touched?

2) How much clearance is there between the turbulator and the tube wall? Is it a pretty snug fit, or do they provide some clearance?

I could get a whole series of them with different twists and clearances and gather exhaustive test data, but life is way too short.

 

[bbb123]

When my fire dies down I'll take a picture of the tarm ones. I have to clean it anyway. There just a zigzag piece of metal the width of the HX.

 

[steam man]

I just looked at some the other day for an oil boiler. I thought they would be like a wood drill bit helix kind of thing but it was more like approximately 3/8 inch wide heavy spring steel that looked more kinked than twisted (although I think it was twisted). It fit a little "snuggly" but certainlty not tight. The points may have been a couple of inches or so. I believe depending on which tube the turbulator is located that it could be slightly different. He did cite the increased distance the gases have to theoretically travel with the turbulators and it was probably 2-2 1/2 times the normal straight through flow. Basing it on that, you could calculate the length of the helix to increase your flow path. Come to think of it, if I can find the energy today I will go and see if I can take pictures and get the design criteria for you. I drove 7 hours roundtrip to take my 14yo son and his friend to an Ozzy Osbourne concert last night. I am a hurting unit. What a show though-all the pyros here would have liked it.

 

[Sting]

The Kewaunee boiler I worked with in a past life used a helix spiral turbulator after we converted it from Coal to NG

On Coal it would soot up fast enough with out help.

The corn boiler I now burn came with a flat plate design - it sports stamped "windows" to swap the hot products of combustion back and forth in the fire tube. I don't have a pic here but Ill post one from home tonight.

I imagine there are as many ideas to these designs are there are stories in the naked city!

 

[EricV]

I'm guessing from memory (always a bad idea) but i think the space is about 3"

I'm doing a complete cleaning tomorrow I'll take measurements all around for you.

Eric

 

[Eric Johnson]

Never seen mine out of the tubes, and I hope I never do.

On the clearances, all I can say is that they're loose enough in the EKO 60 so that ten of them move up and down rather freely when you yank the handle, so I would call that relatively loose. How's that for my usual level of precision, nofossil?

 

[barnartist]

This may not be of service NoFo, but I made mine, and they are too tight, but still work-just too hard to remove. Mine would touch 4 times and a half.
For what its worth, I had a steel shop guy slice me these, 1/8 inch steel. Took them home, mounted 2 vises on a table to hold both ends. Then took an oversized cresent wrench anf from the MIDDLE, turned it 2 or 3 times. worked great. it also sort of makes the air change its twist. It dropped my stack 75-100 degrees. I think one more twist would be OK too.

Might be more info than you wanted.

 

[Sting]

Never seen mine out of the tubes, and I hope I never do.

Don't you have to regularly "punch" your fire tubes?

 

[barnartist]

here is a pic of the terbs.

 

[Eric Johnson]

Great pic, barnartist. Thanks!

Sting: The EKO has a rocking mechanism that moves the turbulators up and down in the tubes when you yank on the handle, so they don't get clogged up. I pull it every time I load the stove. The soot and fly ash just falls back down into the ash pit. Here's a couple of pics. I modified the stock handle with an old snow shovel handle so that I can use the cleaner from the front. The other pic is the top of the rocker assembly, looking through the chimney connector and the open bypass damper, through the firebox and right at a stack of wood.

 

[EricV]

That's a real nice system.

On the Tarm you have to take the cover off and remove them and brush it out the tubes. Quite a messy job with the dust flying.

 

[Sting]

Wow - pretty advanced compared to my baby boiler

these are my turbulators

 

[Eric Johnson]

Wow. Nice!

The turbulator design is interesting, too.

Can you tell us a little more about your corn boiler, Sting?

 

[EricV]

What turbulator? Oh, yea, I see it now

 

[Sting]

Wow. Nice!

The turbulator design is interesting, too.

Can you tell us a little more about your corn boiler, Sting?

If you have time take a look here
http://www.iburnpellets.com/index.php?option=com_frontpage&Itemid=1
I burn the exact same make and model version but heat a slightly larger load
I post there as author stingthieves - check out the forum and the Traeger threads where I lurk.
Also for grins check the link to the corn burners web site

I could use a hand helping some of the nice folks there with wet system questions - you guys are head and shoulders over my knowledge.

 

[jebatty]

nofossil - I placed a post several weeks ago suggesting simply using a piece of 1/2" chain suspended down the vertical hx tubes, using a 20d nail in the top link to bridge the hx tube. Tarm tubes are about 3", so a chain provides clearance on both sides. I did this, but also welded the nail to the top link to make it easer to insert, remove and suspend the chains.

The goal of efficient heat transfer is for every heat molecule to come in contact with the hx tube to transfer the heat. The chain does this pretty well by mixing up the gas flow.

When I talked to Tarm about turbulators, Tarm advised that the ones Tarm sells ($20/each) should drop the flue temp by about 100F, which means an extra 100F of flue gas temp transferred to the water. I achieved every bit of this and maybe a little more with the chain, so my guestimate is that the chain works as efficiently as what Tarm sells, and at very low cost. BTW, I don't know the design of the Tarm turbulators.

You might find this interesting:
http://qirt.gel.ulaval.ca/archives/qirt2002/papers/015.pdf

 

[Sting]

you can see that these anemic sheet metal devices are stamped slightly off center
I only surmised it was to keep the hot gas from bypassing all four steps on the same side
but that leaves a rather weak spot and after two seasons of pulling them twice a week
- well they will be worse for the wear

I like the 1/2 inch suspended chain idea for a cheep single pass vertical fire tube boiler!

Like mine!

 

[Nofossil]

Thanks for the feedback. I'll post pictures of mine as well as data as soon as I get them.

 

[bbb123]

Here you go nofo.

 

[Sting]

From an appliance manufacture of that stature and at the alleged cost each

well I expected to see each zig zag compounded with a twist

(broken link removed)

(broken link removed to http://www.energysolutionscenter.org/BoilerBurner/Eff_Improve/Efficiency/Turbulators.asp)

 

[Sting]

Eric!

Ready to start burning corn now?

Wow. Nice!

The turbulator design is interesting, too.

Can you tell us a little more about your corn boiler, Sting?