New rocket Stove

My new Rocket stove with a bigger burn chamber
The riser is 6" dia and 3" from top plate
It burn well with out the top plate but smoke with the top plate on.
is my riser tube to close to the top ???

I would think, 6 inch riser, equals 6 inch exaust.

rom before you cut anything retest it again leaving the top on this time as the top does another function as its warming up to high heat i believe as it hits high heat is how it becomes smokeless

otherwise in a way you are running it from cold each time you put it on and take it off with the cap

with the gap on the door leave this for now id suggest and do a retest

Hi welcome.
             The secondary air you have there is not going to work. Because secondary air must be pre heated and Very very hot!!  This very very hot secondary air will then relight the unburned gasses/smoke in the bottom of the riser, also your fire box must be hot and have a good amount of burnt embers/coals, for a clean burn. When steel is cold it will draw heat. So until all the steel becomes very hot you will have smoke. :) 
..Your big problem here is Your chimney "out" it is way way to low it will not draw it needs to be above the level of the burn chamber  

That is a mighty stove.
First, lets talk about secondary air. I always leave secondary air open in my stoves, never close it or control it while firing the stove or operating it. I always try to build secondary air entrance lower than the dispenser inside the stove to avoid smoke coming out firing while the all system is cold. Also 2ndburn is right, you should warm up your secondary air as much as possible to allow easy ignition of the smoke. Anyhow, I believe that your current secondary air setup is helping to burn smoke when your stove is really hot.

Second, lets talk about smoke from the chimney exit. In order for the stove to work in a simple way, without the need to build bypasses, the chimney has to be at least a couple of inches above the bottom of the combustion chamber, otherwise exhaust gases from the combustion do not exit easily. This is pure thermodynamics and chemical reactions balance...Because exhaust faces some difficulty to exit, exerts pressure over the system, air does not flow in easily and t combustion does not run complete enough. I would strongly suggest you to raise you chimney exit at least to middle level of the combustion chamber. Also assembling a couple of metres of chimney, will allow a better combustion of the stove.

Third, insulation of the riser tube. From my point of view, and it may be that I am terribly wrong, I do not see the need for insulation in the riser tube. This is a space heater stove, not a cooking stove, the riser tube is inserted inside an heat exchanger that is already hot, so, no need for insulation, your main goal is to get has much dissipation of heat into the environment as possible.

Gladly might be correct. all steel and paint will smoke, if this is the first fireup, then is it just heating and burning off crap? just like the outside was doing? is that fire smoke? or initial burn off junk?

Retest would be best.

caotropheus wrote:

Third, insulation of the riser tube. From my point of view, and it may be that I am terribly wrong, I do not see the need for insulation in the riser tube. This is a space heater stove, not a cooking stove, the riser tube is inserted inside an heat exchanger that is already hot, so, no need for insulation, your main goal is to get has much dissipation of heat into the environment as possible.

caotropheus, I have also questioned the insulation for the riser tube when used inside a heat exchanger,I agree in the same way as you do.

First, since I am in no way any RS build design expert, I can only go from other people who have built successful RS operating stoves.

Second, after I thought about the real purpose behind having the insulation on the riser tube. I came up with, faster operating temperature and efficiency over none insulated riser tube.

Third and maybe way off target, I thought by keeping the core heat last longer, this in return would keep the rocketing of the stove longer as the fuel runs out?

This is the part of the Forum I like best!  

twistedkarma wrote:

  Gladly might be correct.   all steel and paint will smoke,  if this is the first fireup, then is it just heating and burning off crap?  just like the outside was doing?   is that fire smoke? or initial burn off junk?

  Retest would be best.

Any first time test burn should be done in a well vented area. If not outside with a breeze moving the fumes away from you, then some type of fan venting the toxic fumes out of a closed area.

Paint isn't much different then the galvanized coating on iron. The process is different, both have the same health and safety hazards when working with them. Toxic fumes given off by the heating of them, and the hazardous air born partials from the sanding or grinding.

Some type of PPE ( personal protective equipment ) is better then nothing when working with these types of hazards. 

Two things, one very important thing, it starts to smoke when you put the top on because you kill your draft, you have no chimney on it to help produce a draft.

As one other person said you need your chimney to be just above the firebox.

One other person pointed out your secondary air will need to be pre-heated, you can do this by running your secondary air through the firebox.

I like your idea, I think it will work when you make the adjustments.
Nice work on the door and window.

gadily wrote:

rom before you cut anything retest it again leaving the top on this time as the top does another function as its warming up to high heat i believe as it hits high heat is how it becomes smokeless

otherwise in a way you are running it from cold each time you put it on and take it off with the cap

with the gap on the door leave this for now id suggest and do a retest

I did retest,after 1 hour the stove was still smoking, i will make some change and retest tomorrow
thanks

if your exit is 6 inch, and reduced by half? that's some of your issue. also a chimney, attached to your heater will help with draft. Mine would act funny at times, 3 days testing in drive before moving to a chimney. I moved it indoors, and staigtened out some lighting fire issues and draft.

https://youtu.be/o8A62YRvPmw

Hey Rom1nb,

Looks like you have put a lot of work into this so far.

I don't want to wade into the insulation / no insulation debate for the riser tube as the arguments being made by some regards the riser already existing within a heated environment (from the gases) etc. All I will say, is that with insulation all of my test burns (and there have been many   ) have showed that it achieves a 'smokeless' burn quicker - which makes sense. I would also hazard from wood burn rates that there is a stronger draw also.

Anyway - enjoyed watching. Good luck with the modifications.

Bezman

made some change to the stove ,move the fire box and the exhaust pipe
look like it working
Thanks for all your comment and suggestion
what do you think of red for the color of the stove  :)

Hi rom1nb, "Congratulations" lots of work but well worth it. I hope it Keeps your home worm and toasty  

Congratulations for the success on the stove. Looking forward to see the final version of the stove. At the begining when you light the stove, there is some smoke coming out because the ash tray door was open. If you close this door, I think that there will be no smoke coming out. Also when you install the chimney, there will be less smoke coming out when you load wood.

caotropheus wrote:

Congratulations for the success on the stove. Looking forward to see the final version of the stove. At the begining when you light the stove, there is some smoke coming out because the ash tray door was open. If you close this door, I think that there will be no smoke coming out. Also when you install the chimney, there will be less smoke coming out when you load wood.

Yes caotropheus,  I think you are right about the chimney, also there are probably steam vapours.