conventional kilns

[woodhick]

Just wandering if anyone out there is running a conventional direct vent kiln.  There are smaller one's on the market now for  800-3000 bd ft.  Most use electric for heat.  Seems to me the cost of a dehumidification unit would pay for a lot electric to run one of these types.   ???

[Ga_Boy]

Welcome aborad Woodhick.

I am not running a convential kiln, but as soon as my business loan comes thtough I will be.

My plan is to use slab and other wood waste to heat the kiln via a Heatmor out door wood furnance, I'll also use the furnance to heat the shop and house.  No more propane bills 8) 8) 8)

There are several vendors selling the controlers and if you so desire turn key ops.  For me, I'll save that $20K and build it myself with off the shelf parts.

Let me know if you have a specific question.




Mark

[DanG]

Conventional indeed!  If it's so DanG conventional, why can't I find any info on it? ??? :  I can find all kinds of plans for solar, dh, and even vacuum kilns, but nobody seems to even have heard of a conventional kiln.  I know the basic principles of their operation, but I'd prefer to not have to go from ground zero and work it all out for myself. These things have been around for a lot of years, so it shouldn't be that hard to come up with some plans.  I understand that they aren't all that energy efficient, but I'm burning tons of slabs, edgings and sawdust in a big pile in the pasture, just to get rid of it.

[serg]

Hello! I am constant on a forum. A theme of work of the simple chamber, I so have understood ???? Use of the boiler on wooden waste products of manufacture ???? If I have correctly transferred(translated) that at me there are working drying chambers under such circuit. Dry a pine 52 ìì.îò 60 % up to 6 % W. Temperature of stable 75 degrees C. I use them in a complex for a conclusion of free water from an oak,  a nut. The pine is used by me seldom. I have put one complex on pairs. 165 degrees C. Pressure pair 3 atmospheres. Works 5 chambers. Volume of loading of all chambers of 50 meters cubic. Term of drying of 8 days. Work without a computer. Only two exhaust channels one for receipt of air. The second complex works on an electricity. One chamber consumes 15 KW. Hour. Volume of loading of 12 meters cubic. The heat-carrier water of 95 degrees. Sergey.

[woodhick]

 Dang,  I have checked into two different brands of this type of kiln.  Both come standard with electric heat but a wood fired boiler would be even better. I built one of these on a small scale to dry 400' and it works great.  I don't have enough heat in this one to dry green, but it works good on air dried down to 6%.  I read posts on here all the time but don't post much myself.  I beleive sometime back there was some talk about not posting company names on here.  If Jeff would clear this up for me I would be glad to give the names of the companies that manufacture these.  I really appreciate the info I get Here and don't want to impose on any rules.  These kiln are basicaly a insulated chamber "same as a DH kiln" with a heat source and a venting source.  Wood is heated and moisture is vented off  periodicaly.  To condition you need some type of water mist or steam.  These use all off the shelf products and seem very reliable just cant beleive why everyone is hung up on Dh kilns.  I really beleive I can build on of these for a lot less than a DH unit would cost.  For my needs of 1000' I thank this is the way to go, just trying to get any more info from someone who has done it.  I enjoy building my own equipment.  That way I know the ins and outs of all of it.  Always trying to learn more :P ???

[woodhick]

 What I ment to put in the above post is I don't want to infringe on Nyle DH kilns by posting the name of others on here.  I have researched Nyle and I beleive they are the best in the market for larger volumes, or for areas where energy costs are high.  Plus they have excellent tech support with Don Lewis.  I am just  trying to find out if anyone is doing something different than DH or solar or vacum.  Thanks .

[Ga_Boy]

DanG and Woodhick,

You will need to buy a controler to monitor the temps (dry and wet bulb) and open and close the vent.  Controlers are available from PC Sepcialits (Den), Kiln Direct and a host of other outfits.  Do a Google serch for "Kiln Controler" and you will find all you want.  Another option is to visit Wood Web and check out some of the sponsers, they also sell controlers.  Note:You can subistute a RH sensor for the dry and wet bulb thermomitor.

After that you need a heat source (burn wood waste), fans, a heat exchanger and chamber.  

Now fill the chamber and follow the published schedules for the species that you are drying and voila; you have yourself a kiln.

Now I went and let my brain child out of the bag.   :D




Mark

[Hokiemill]

Woodhick,  I think there are a few of us out here who are curious about using conventional kilns for smaller loads.  Take a look at a thread titled "Is simpler better" on 5/18/04 and "Northland Kiln" on 5/21/04.  I know that Kedwards and SteveST both run the Northland kilns.  SteveSt was trying to sell his at one time.  Ultimately, it sounds like you might have as much info as anyone since you've already built a small conventional kiln.  Tell us more about it - it sounds like exactly what I plan on trying.  How do you heat, how do you control, how do you vent, how did you build the chamber, etc. etc.

An experimental 500 bdft conventional kiln is on my to-do list.  I know DanG is also interested in going down this path.  Maybe we can collectively put together the ForestryForum Conventional Kiln Design.

[Xylophile]

The folks at Koetter Woodworking have been building "conventional" kilns for some time.  Except that they don't have an expensive conventional pressurized boiler like the "conventional" guys.  Their older kilns used wet bulb/dry bulb monitoring, with a simple controller to raise and lower the set points.  Not sure about the newer models.  Add the box, fans and a heat source and you've got yourself a kiln.  Heat could be a wood fired boiler, if you've got the waste.  They used to sell kits, maybe still do.  Worth a look.  

[ElectricAl]

If you want to build your own Conventional Kiln, the controller is one item not to scrimp on.  We have a custom built Nyle wet bulb / dry bulb controller. It controls heat, vent, and additional humidity.

I would suggest making contact with Den or Don and getting a professionally built unit.

As far as Northland kilns they can be ordered with hot water base board heat. Then get an outdoor wood burner.

[Brad_S.]

I own both a Nyle and a Koetter. As Xylophile says, the Koetter is a model of simplicity. Readings are made by injecting water onto a wick attached to the thermometer. Take a dry bulb reading, wet the wick, take a wet bulb reading. Drying too fast?, shut the vent a little, too slow, open it up alittle more. No need for high priced wham bang gizmos with it. I would think with time on your hands it would be easy enough to build one like it on your own.
Mine holds 550 bdft and is all electric. Any larger and I would want to heat with a boiler.

[Hokiemill]

Brad, give us more details on the koetter.  What is your heat source?  How long to dry a full charge, electric costs, etc. etc.  Thanks.

[woodhick]

Brad s.  Thanks for the post as well as everybody else.  You pretty much describe my little kiln to a T.  The kilns that I have looked into but didin't want to metion wre mentioned by other members above.  Everything about these kiln are off the shelf products.  My little kiln uses a drybulb and wet bulb both wired to a recorder.  I manually adjust vents to control EMC inside.  If I need to add moisture I use a small humidifier piped  up to fresh ai inlet.

Hokiemill, to try and answer your questions.
1. I can only dry lumber that was previously air dried because I don't have enough heat.  I am only using about 1800 watts.
2. Kiln chanber is just a plywood box with 3"of foam insulation on the outside and painted with fibered aluminum roof paint on the inside.
3.  I can usally dry a charge of 400'  of most wood's except oak in 8-10days. Anywhere from 17-18% down to 6-7%. Oak will take about twice as long.  I usally condition  at the end of this by adding moisture and controlling vents to keep inside around 7%emc, which is best for my area.
4.  I run a seperate electric meter for my woodshop where the kiln is located.  For most loads  it runs between $25 to $35 more if I have  dried a load of lumber during that month.  Around here central WV electric is " I guess" reasonable compared to other regions.  I still gripe it's too high :'(

I am wanting to build another kiln that will hold around 1,000 board feet.  I plan on starting this very soon and will keep you posted.  Although many thing get in the way, like full time job, sawmilling and cabinet shop on the side.  Right now I'm planning on manual vent control but hope to change to some type of automatic control. :P :P

Thanks for any and all help.  

[Brad_S.]

hokiemill,
Here are some shots of the Koetter.

These are the electric heating elements in front of the circulation fans. The tarp is placed over the lumber load to force the airflow to the back.


This is the view under the tarp. The fan in the forground is the vent fan, the wand to the left of it is the thermometer probe with the wick on it. The tube running to it carries water in to wet the wick.


Here is an external view. The vent is the circular thingy on the left. It rotates on a shaft to allow controlled venting. On the right is the thermometer with the wetting tube above it. The chart is for interperating the wet bulb/dry bulb info and giving you RH and wood MC.


Here is the temperature controller.

All my equipment is on one electric meter, so I can't give you cost breakdowns, but it's not backbreaking. Dry times are equal to a DH kiln, with poplar being about 10 days, oak about 35 and everything else is in between.
Hope this is the info you were looking for.

[woodhick]

  BradS, Thanks for the pics.  Couple of questions.  Does the vent fan cycle off and on or does it run all the time and you just adjust the discharge manually.  Is there any type of opening to let fresh air in on the other side. ???  What's the interior dimensions of your kiln and how much board feet can you get in it.  Also do you now what the watts or btu's of the heaters are.  Thanks  ???

[Hokiemill]

Thanks guys!!! This is exactly the kind of information I'm looking for.  Woodhick - same question as you asked Brad - any inlet venting on your kiln?  BradS - looks like four small fans each with a heating element?  The fans look to be around 12"-18" from the right hand wall?  I don't see any tracks - are you loading everything from the end?

This is great.  Let the construction begin.  But like woodhick, (and everyone else) life seems to get in the way of my side projects. >:(

[Brad_S.]

The vent fan runs constantly with the vent cone determining the discharge. The vent is cone shaped and fits into a tapered ring. The cone twists out on a measured stick with one full turn equal to one measured unit. The cone is also graduated in units of ten. By following a provided cookbook for each species, you set the vent by the required number, i.e. if the book says "vent 25 @ 120 degrees", then you crank the cone out two and a half turns and set the temp to 120.

Looking at the 1st picture in my earlier post, the air inlet is in the lower right hand corner of the kiln at the back.

The interior measures 13' long by 40" wide by 4' high. The lumber is loaded on a cart that is partially visible in the above photos. The cart is aluminum with wheels, 12' 8" long and 28" wide, which is the width and length of the lumber load and is guided in by two small angle iron pieces Tapconed into the slab. A full load of 12' lumber with 1/2" stickers is about 550 bdft., shorter material is obviously less. To help keep the stack flat I have two 13" sections of railroad track I place on the top in lieu of the bungee cords Koetter used. The 'Doc' will tell you that is not enough weight to be effective but I sure notice an improvement in quality. The cart is pushed in (no small feat) and a door is latched on.

I don't know the btu's and it was too DanG cold to crawl around looking for any markings today! Sorry.

I haven't measured, but I think the fans are more like 8-10" from the wall, if that.

I rarely use this kiln any more, just for small runs of custom stuff. Otherwise I air dry and finish in the Nyle. If I need something green to finished in short order, I let a friend who shares the facility do it in his WM Vacukiln.

Right now this kiln sits on an uninsulated slab which causes control problems in the winter. I have an insulated slab poured but I'm not sure whether to hold on to this unit or not yet, so I've been in no hurry to move it.

Did I cover all questions?

[woodhick]

Brad thanks for all the help and pics it will help a lot.  One more question that I can thank of now.  Probably will ask more later.   Is there any control on the inlet vent.  Like slide or shutter or another cone type as the discharge.  Thanks. :P

[Brad_S.]

Actually, I never looked. There is some kind of gizmo there, it's not just a straight pipe or hole. I assumed it to be a critter guard, but I will look closer tomorrow,

[woodhick]

Brad thanks for all the help,   thought of another question.  Do you have any way to condition in kiln,steam, water spray,etc.  :P :P :P

[Hokiemill]

Hey guys this is all fantastic information!!  It reinforces what I've thought all along - conventional kilns are not outdated, they are applicable to small loads, they can be easily contructed, and the operational costs can be reasonable (even when using electric heat).  This is the beginning of a conventional kiln revolution for the small and part-time sawyer. ;D  Let's strive to keep this thread alive with construction/operation updates and newly discovered info.

Thanks again for your input.

[Brad_S.]

Throwing about 10 gallons of water on the floor and sealing it back up is as high tech as I get on stress relief.

Hokiemill,
I applaud your enthusiasm, and if you can assemble all the components for a song and have the time to put it all together you'll probably save bucko's. In my humble opinion, building a chamber and sticking a Nyle L50 in it saves a lot of time and (physical) energy! :D :D

When it came time to upgrade to a larger unit, I considered another Koetter because I understood the theory and was happy with the results. However, I already had an insulated 'flash' freezer available, so I went with a Nyle, and have been happy with that. To me, small scale conventional vs DH is an even wash. It becomes a question of how much time and effort you want to commit to the project.

Please keep us updated on your progress. I admire you guys who can engineer projects like this! Wish I had the time. ;D