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New Turbulators

Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Nofossil, Feb 8, 2008.

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  1. dadams

    dadams New Member

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    Yes, I've just been sitting here looking over the Tarm site and info. Very nice! I was really not familiar with these gasification boilers, but I am quickly growing fond of the idea the more I read this AM. Not having been online on this topic for long time like some, are folks generally having more success with Tarm, Eko, Greenwood, ? Meaning mostly availability, price, durability, reliability. Understanding this is not an endorsment, I am thinking there might not be so much data available with these.

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  2. Eric Johnson

    Eric Johnson Mod Emeritus

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    In the case of the EKO, the turbulators are engineered into the original design. On the current models, they can be moved up and down in the hx tubes to keep them clear of soot and ash. You yank on a handle on the side of the boiler when you load it, and a rocker-arm arrangement makes them move. The crud falls back down into the ash pit/secondary combustion chamber. The BioMax does the same thing, as does the Econoburn, I believe. Tarms and older EKOs can be fitted with turbulators, but you need to brush or scrape out the tubes periodically by hand.

    The Greenwood is a different animal than the EKO/Tarm/Econoburn style gasification boilers. Instead of having a ceramic nozzle with a secondary combustion chamber below it, the Greenwood (based on the original design by a guy named Fred Seton) has a huge refractory mass surrounding the primary combustion chamber, with the hot gas being drawn down through the coal bed and out the stack. Some brands draft up and some draft down. My understanding of that design is that the refractory allows much higher firebox temps, inducing seconary burn. Instead of being surrounded by water, the firebox refractory assembly has water tubes running through it. Firetube vs. watertube, I guess. The former has blowers, while the latter typically relies upon natural draft.

    Those are significant differences in design and function, but they both accomplish the same thing, which is a clean, efficient burn.

    Here's a couple of pics showing the top of the EKO hx with the rocker assembly and tops of the turbulators visible. The steel disc is the open bypass damper. Since I have a very tight squeeze in my boiler room, I attached an old snow shovel handle to the stock handle so that I can move the turbs from the front. Good thing, too, because I probably don't have enough room to manually clean the hx tubes, at least not more than once a year.

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  3. Nofossil

    Nofossil Moderator Emeritus

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    Design of a wood gasification boiler has a huge number of compromises. In the case of the EKO 25, they made one mistake in my opinion - they made the boiler shorter than the other models in the EKO line. That means that the upper chamber is smaller and much worse, the HX tubes are shorter. I have six HX tubes with an inside diameter of about 1.845". They are only 21" long, so I expect that anything that can be done to make them more effective is effort well spent.

    If they had made the boiler 8" taller. it would still fit in the same space, but it would be more efficient and burn longer between fillings.

    My first fire with the turbulators had the highest temperature drop across the HX tubes that I'd seen - about 110 degrees higher than the previous week's average. Last night, the temperature drop was another 160 degrees higher than that. As I mentioned, I'm burning highly variable wood, so I can't easily do a fully calibrated efficiency run just yet. Numbers look good, though.
  4. barnartist

    barnartist Minister of Fire

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    Eric, you have me doubting myself. Im really sure I have 16. Sled_Mack, this sound right? Eric, your boiler is newer, but ten tubes (-6) would that mean you would have less transfer, or are your tubes just bigger or deeper?
    Id like to see chain results compared to spirals too. Even a small amount of improvement would be worth the change. With only 6 tubes it should be easy to try.
  5. Eric Johnson

    Eric Johnson Mod Emeritus

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    I'm pretty sure I counted ten, but I get the impression that the design of the 60 changed somewhat in recent years. I know the refractory brick setup sure did, because you've only got two u-shaped deflector bricks, while I've got 3.
  6. leaddog

    leaddog Minister of Fire

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    Very interesting. I bought the eko60 from Barnartist's uncle that they had gotten together 3 years ago and I have found several things different. There is 16 tubes. The fire box is flat and the pipe fittings are flange. The elect. is 220 stepped up from 110 also.
    The flat fire box might cause the bridgeing that some were talking about. My son is going to be hooking this one up this spring and we'll see how things work. I don't see where the changes will be much difference. I haven't had my 80 apart to look at the tubes to see if they are bigger but I suspect they are. It would be easier to weld them in plus putting the turbulizer-cleaning parts in would be easier.
    leaddog
  7. Eric Johnson

    Eric Johnson Mod Emeritus

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    When you say the firebox is "flat" do you mean that there's no refractory "trough" above the nozzles. The steel in the firebox is vertical, but there's some refractory pieces on the sides that form a sort of u-shaped chamber above the nozzles.

    How many firetubes in your 80, leaddog?
  8. leaddog

    leaddog Minister of Fire

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    The older 60 has a flat bottem, no trough. It is refractory but flat. I have fire brick and if it seems to not flow the ashes down to the nozzel I may put some in to help.
    I don't know how many tubes in my 80. I'll have to look when I get time. I was going to see if I could buy the turbulators and rocker arm for the 60 but I'm thinking that the new ones won't fit. Looks like I'll have to get my thinking cap on again and make something that will. The chain idea might work if I can come up with some way to rattle it??????? To many projects and not enough time.
    One other change is the damper as it has rope seals. I'm going to make sure I coat it with grafite good before we use it as I can see where the high heat could cause a problem. If it gives trouble I will replace it with a solid one like my 80.
    leaddog
  9. mack7

    mack7 New Member

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    Eric, I also think there are more than 10 in there, If you look at your picture you have of them there are 4 just in the chimney opening and I know they go all the way to the sides. I am going to have to tear into mine soon just to check things out so when I do I will count them.
  10. sled_mack

    sled_mack New Member

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    The older 60's do have 16 tubes. They are just under 2 inch diameter, if I remember correctly.

    The bottom of the firebox is flat. I rely on ash to keep a trough in there. The new ones are not flat? If so, what is the shape? I've thought about trying to get some refractory to make a V shape, but haven't gotten around to that yet.

    Can anyone post some pics of the new 60 at the top of the hx tubes? I'm interested in seeing how tough it would be to retrofit the turbulator shaker to the old ones. Does it use the same handle that opens the flap, or a different handle? Seems chain would be really easy to make up for this since alignment wouldn't be much of an issue?
  11. Eric Johnson

    Eric Johnson Mod Emeritus

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    I've decided to pull the pipe off this afternoon after my boiler cools off a bit and check it out. I'll count the tubes, measure their diameter and snap a couple of pics of what it looks like.

    I want to inspect my chimney and scrape some creosote off the rim of the bypass damper opening, so this is a good opportunity to get it all done.

    Anything else you guys what me to check out or photograph while I'm back there?

    BTW, the EKOs that Zennon is importing now are all the Orlan EKO Super model. The Super is the fancy version with the hx cleaner and cooling coil. Plus, it sounds like there have been some interesting changes in the refractory and possibly in the hx tubes between the two versions.
  12. leaddog

    leaddog Minister of Fire

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    Take some pic's of the cleaning shaft connections so I can see if it can be retro fitted to the older 60's
    I'm thinking that I might have to rig something up and use the damper shaft to move things at the same time as i open and close the damper.
    If you can't post all those pic's you can send them to my email.
    leaddog
  13. sled_mack

    sled_mack New Member

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    Eric,

    The older models have a rectangular cleanout plate directly above the hx tubes. It would give you a much larger area to work through to do what you want.

    Like Leaddog, any pics of the connections to the turbulators would be really useful. Putting a new hole through the side of the boiler seems much more difficult than using the flap mechanism.

    Leaddog,
    What kind of solid gasket is on your flap of your 80? Mine had the rope seal, the disintegrated pretty quickly. Nothing else stayed on the flap. I ended up putting a big rope gasket around the nipple where the flap makes contact instead. I put a really long hose clamp around it to squeeze it so that it seals up to the flap a bit. It's not ideal, but the creasote fills in the gaps and keeps it from leaking.
  14. leaddog

    leaddog Minister of Fire

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    My 80 just has metal to metal on the flap of the damper. It seems to seal well. Barnartist told me he changed his to metal to metal but they had to bend the bracket so it would close tight. I think I might go a head and rework this 60 before we put it in service as it will be out where I can work on it.
    leaddog
  15. sled_mack

    sled_mack New Member

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    The bracket does bend easily. I had a small chunk of wood get up in there early this year. Sure enough, when I tried to close the flap it bent the bracket. Fixed it by clearing it, putting a small piece of wood at the bottom of the flap and slamming it closed a few times. Seals nice now!
  16. barnartist

    barnartist Minister of Fire

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    Leaddog, I still use the rope on the damper, but my cousin went metal to metal. I found some extreme high heat glue that finally held my original gasket rope in place.
    Be carful not to bend the rod arm that the bracket is attached to, I think I stuck a piece of 1/2 inch wood between that rod and the boiler wall, then used a big nail bar to bend it where it needed to go.
    It seems adding a trough to the upper chamber would help some. For me, and this is probably from my buring habits, I get lots of unburned coals in my bottom chamber. Id like a way to add a grid to the nossils to keep these coals up there longer, but not sure if there is a material that would withstand those temps.
  17. dadams

    dadams New Member

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    High Nickel alloys such as HK-40 or HP-mod should do nicely as they are typically used for furnace tubes at temperatures up to about 1800 F
  18. Eric Johnson

    Eric Johnson Mod Emeritus

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    Well, I stand corrected. The 60 has 16 tubes, just like barnartist said. I couldn't get a tape right over one to measure, but it's right around 2 inches. The turbulators are 1.5 inches wide.

    I was pleased to see zero creosote anywhere but the firebox. The chimney is clean as a whistle, and I only had some fly ash and soot in the cleanout. Everything else back there has a thin layer of fine, brown soot. I couldn't get a good pic of the mechanism that moves the turbulators, mainly because the pivot mechanism is under the side panel and not visible from the rear. I can't get my side panel off, but I did before putting it in there, so I know what it looks like. Nothing goes through the water jacket, by the way. There's a shaft running over the top of the turbulators that drives the thing. I'm sure you engineers have special terms for that stuff.

    Here's a couple of pics. The one in the lower right shows the lever that rocks the turbulators. The shaft I mentioned is that brown thing just visible through the flash shadow in the upper right above the lever.

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  19. Eric Johnson

    Eric Johnson Mod Emeritus

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    Here's a pic of the refractory trough at the bottom of the firebox mentioned earlier. Please excuse the mess!

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  20. leaddog

    leaddog Minister of Fire

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    Thanks, looks like I can copy mine and make it work in the 60. I see how it works now. It don't look like it would be to hard to copy. But maybe I'll give dave a call and see if reto kits are available.
    It looks like there must be about 1/4 in clearance on the sides of the tubes so a close clearance isn't important.
    The pic's show alot on how the eko is made for the people who haven't seen one.
    leaddog
  21. sled_mack

    sled_mack New Member

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    Hmmmm..... I wonder if some home-cast refractory would hold up if used to make a trough like that? Surely it would work better than just having ashes built up like I have.

    I'm still confused on the turbulator mechanism. If you take the top cover off the boiler, is the rod visible? When you activate the lever, what motion do the turbulators make - up and down? Where is the point were the rod enters the boiler that it doesn't come through the water jacket? That's what I'm really stuck on.

    If you have 1/4 inch gap on either side of the turbulator, does it do a decent job of keeping the hx tubes clean? I use a brush made for pellet stove tubes to clean mine. It's a tight fit, but cleans very well.

    A retrofit kit would be interesting. Maybe some drawings of it would make things clearer for me.
  22. leaddog

    leaddog Minister of Fire

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    It looks like the rod is up high and has a lever coming out each side of it that is connected to the flat bar that the turbulators are connected to. I'm sure that there is corresponding levers on the oposite end to make the flat bar level. By moving the outside handle it would rotate the rod and move the levers up and down which would in turn raise and lower the flat bar and in turn the turbulators. I know clear as mud. I'd draw a drawing but I don't know how to post it.
    leaddog
  23. Eric Johnson

    Eric Johnson Mod Emeritus

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    I've never taken that plate off of mine, sled, but I do have one. The rod runs right underneath that plate--probably between the two sets of tubes so that you can get a brush or scraper into the tubes. Thinking about it, I'm not sure now whether the mechanism goes through the water jacket or not. Leaddog might be able to answer that question. The turbulators move up and down, I'd estimate about 4 or 5 inches total. There's some resistance when you pull the handle, so metal is hitting metal inside the tubes. But it's not hard to move at all. As to how clean it keeps the tubes, I can't say. Clean enough for the turbulators to move up and down.

    As to home casting refractory bricks, I'd like to try that, too. I think you mentioned that you talked to Zennon and he had a better design than the u-shaped bricks that come with the stove. I'm sure it would be pretty easy to build a mold and cast your own. I just don't know if you'd have to get them kiln fired or not. I bet you could get a bag of that refractory that Fred Seton sells and make something out of that.
  24. leaddog

    leaddog Minister of Fire

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    I think you could take some fire brick an lay them in some refractory cement an make a trough. I have some 2x4x8 bricks that I think I will cut on an angle. You can buy refractory mix here on ebay. http://stores.ebay.com/FIRE-and-ICE-Supplies
    leaddog
  25. sled_mack

    sled_mack New Member

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    Seems like the refractory there would not take as much abuse as the lower chamber as far as temperature is concerned. Plus, they will be somewhat protected with ash after the first few fires. Zenon originally said just putting the refractory in an oven at 400 deg for 5 or 6 hours would be enough to drive out the moisture that causes cracks. That might be enough for these trough pieces for the upper chamber?

    That being said, it seems like it would be a huge advantage to have refractory up the sides of the chamber as well. The more heat kept in the fire area should greatly help with gassification, no? The problem I see is any refractory up the sides getting destroyed when loading the fire.
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