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Totally offset barrel / heat riser  RSS feed

 
proteas vryssas
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I don't place the barrel on center of the heat riser. The barrel's front side has almost all the space to the heat riser, while the barrel's back side is touching the heat riser.
Would that offset be a problem which leads to incomplete burning? The feed area is smoking, so my rocket stove doesn't have a good pull and only half of the gases and flames goes into the burn tunnel.
barrel_offset.jpg
[Thumbnail for barrel_offset.jpg]
exhaust.jpg
[Thumbnail for exhaust.jpg]
 
shilo kinarty
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no problem
cob the bench and wait until it dry
 
allen lumley
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proteas vryssas : Ianto Evans' whose observations of many different Phenomena lead to todays rocket mass heaters RMHs, and the Great book Rocket Mass Heaters

Cobcottage.com Reports in "The Book'' that offsetting the barrel always created a cooler side and a hotter side and as long as there was sufficient Cross Sectional Area

left for the gases to flow through and the diameter of the opening at the bottom of the barrel was large enough this could work well and help protect flammable structures

near the barrel. It has been reported here that with a gap between the top of the Heat Riser and the underside of the barrel greater than 3'' this temperature difference

reverses itself !


Being very stingy with my money is my best reason for going with cob instead of concrete; However in your case the concrete does not seem to be absorbing the water

released from /and produced by the wood you are burning. Always burn the driest wood you can ! Cob is generally highly regarded for its ability to hold onto lots of Water

when the moisture levels are high, and venting it when the Moisture levels are low !


Running a small fan to increase the movement of air through your RMH will help dry things out but you need to vigilantly look for other outside sources for your water

problem ! Again the fan should help stop smoking at the feed tube ! How tall is your final Vertical Chimney?

For the Good of the Crafts ! Big AL
 
proteas vryssas
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allen lumley wrote: It has been reported here that with a gap between the top of the Heat Riser and the underside of the barrel greater than 3'' this temperature difference reverses itself !

The distance/gap from the heat riser to the barrel's top is like 1.5 inch at the center and 3.5 inch at the outer edge of the barrel because my heat riser is something conical on its top.
Currently I had remove the barrel to increase the distance between the barrel's top and the heat riser top, believing that there is a bottleneck which slows down the gases. By using the grinder I cut the original barrel's top and left only the extra thick welded metal plate on barrel's top adding 0.9 inch.
But because of the grinder's wheel size I can't get access to the outer edge of the barrel's top living 1.7 inch "teeth" which of course travel all the circumference of the barrel.

allen lumley wrote:Being very stingy with my money is my best reason for going with cob instead of concrete; However in your case the concrete does not seem to be absorbing the water released from /and produced by the wood you are burning. Always burn the driest wood you can ! Cob is generally highly regarded for its ability to hold onto lots of Water when the moisture levels are high, and venting it when the Moisture levels are low !

I don't know how strong the cob will be and I don't know how to make it, neither anybody else, like people who build fireplaces here knows about it.
The price here for 1 cubic meter of concrete with the transportation cost is 55 to 60 euro. So that should help me because currently I don't have a car.

allen lumley wrote:Running a small fan to increase the movement of air through your RMH will help dry things out but you need to vigilantly look for other outside sources for your water problem ! Again the fan should help stop smoking at the feed tube !

I have a strong fan sitting around here, left out of RMH as my last resort.

allen lumley wrote: How tall is your final Vertical Chimney?

My chimney is 90 inch tall.
I think the only thing left to pulling gases out is the chimney's pull because the speed the gases acquire while they travel upwards inside the heat riser, should be zeroed when the gases hit the top of the barrel.

I also manage to:
a) if the increase of the barrel's gap will not solve the wood feed back smoking problem I will remove the first exhaust pipe and I will add some slope to it so the gases will gain some speed there too.
b) Add two drainage pipes each under the lower point of the two exhaust pipes.
c) trying something irrational which if worked should solve the liquefaction problem like pointing all the exhaust pipes with a downward slope and then add the chimney.


 
allen lumley
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proteas vryssas : Please answer clearly, what kind of floor do you have under your RMH, have you covered your piping now? And was the piping covered before

when you discovered the water problem ?

Your Final vertical chimney should be an internal chimney exiting near the peak of your roof! With an outside chimney it needs to be located on the Lee or Downwind
side of your house and be at least 1 meter higher that the peak of your roof, or other nearby object !

please update me on this For the good of the craft! Big AL
 
proteas vryssas
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allen lumley wrote:proteas vryssas : Please answer clearly, what kind of floor do you have under your RMH,

Under and around the barrel area I have 2"+ of concrete then under it 1.2" blue dow like styrofoam then 12"+ main concrete floor.

allen lumley wrote:have you covered your piping now?

No, the weather turn to snowing condition. The cement instructions I used (which the same for houses (type 42.5N)) prohibits to work with it at temperatures below 10C.

allen lumley wrote:And was the piping covered before when you discovered the water problem ?

No never. I only remove the dow styrofoam sheets which laid under the pipes too, to clean out the water. I'll wait until the temperature going like 8-10 C (50F) to be able to work with concrete again to place the taller barrel I made (look at my previous post).

allen lumley wrote:Your Final vertical chimney should be an internal chimney exiting near the peak of your roof!


I never though that I could have an internal chimney. Would that internal chimney be drag heat continuously from the room up to roof and thus the outside air, even when the rmh is off?

allen lumley wrote:With an outside chimney it needs to be located on the Lee or Downwind side of your house and be at least 1 meter higher that the peak of your roof, or other nearby object !


I don't know anything about Lee or Downwind and I don't want to read what the wikipedia writes about it because previously I had a 3m (120 inch) tall chimney made of bricks for a fireplace at pretty much the same area.
But the fireplace had problem with the back-smoking inside the room. !@$%&# Then one professional fireplace builder come and said that it needs to be raised again and when that didn't work either then another professional fireplace builder come and place a expensive and aloud motor on top of that chimney. After a while the motor stack because of ash, creosote and harsh conditions. But the motor "solution" had some other side effects! When worked to drag the smoke from the room, it is also remove all the heat produced by the fireplace and make the room loud too. So I don't ever need to know what the Lee or Downwind or the common chimney builders technique said (no offense).
 
allen lumley
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proteas vryssas ! When Ianto Evans -the Genius who put together several different observations to create the rocket mass heater RMH from the earliest predecessors

of the rocket stove went in search of a location for what grew into Cob Cottage { Cobcotage.com } He found a place on our wast coast that had a short heating season

with stable Winds promoting ease of operation .


All of his early structures were built around already built RMHs . Most were egg-ish shaped (or like a bottom mushroom) and most were one story. With these

pre-conditions Iantos' early RMHS Seemed to work flawlessly, and got a reputation for only needing a little chimney (still on the lee side -always ) !

You on the other hand are trying to retro-fit a rocket mass heater RMH into an existing structure. Some compromises will be necessary, when we find a RMH that

has problems Creating a decent Draft, It is very common to find that the owner/builder has cheated himself by not using enough chimney ! Given two RMHs totally

identical except for the Chimneys the taller chimney will always have a better draft -Always


So- tell me again exactly what happens to your horizontal chimney from its ending through how many elbows or tees and how much stove pipe you have to add to get
up AT LEAST 1 Meter above the peak of your roof !


About how you are feeding your rocket, The Ratio of Dry Wood to Air must be carefully controlled, if all the barrel and piping fittings are tight you never should have

visible condensed steam in your clean outs. This can only leave Wet Wood or Way to much air flowing through the Feed Tube opening and cooling the Combustion

Zone

See link Below :


http://s65.photobucket.com/user/mremine/media/NYC%20Rocket%20Stove%20Build/P1030331.jpg.html?sort=3&o=6


Notice the Amount of wood being burned. Here two bricks have been used to partially close off the Feed tube opening. This helps our fire in more than one way. 1) By

Flowing Downward past the sticks of fuel wood it cools the sticks preventing smoke back! 2) as it flows through the fire the Air warms up and keeps the Firebrick that

lines the Burn Tunnel and the Heat Riser Hot. Thus the proper Wood Fuel To Air Ratio keep excess air from cooling you combustion zone !


While we start with tinder and then kindling , we can fill the Feed Tube opening with small very dry wood and within 15 minutes have the walls of the Burn Tunnel glowing

Red

Take a look again at the picture, regardless of the amount of wood you feed your rocket you must restrict the amount of air you feed it.

Even though it may look like your wood is crowded it is not; Your best Tool to operate your Rocket correctly is your ears. When your rocket is running correctly you will be

able to hear its roar ! and within 15 minutes you should be able to look at the Burn Tunnel Walls and see that Red Glow ! ( the room may need to be dark )


After you have that sustained glow you can slowly increase the size of the pieces of wood you are burning, but always have at least 3-4 pieces in there at all times to help

create channels for the air to pass through on its way through the Combustion zone ! Don't worry Tending to your RMHs fire by ear will soon become second nature , an

Automatic process done with no more thought than you would use adjusting a pair of glasses on your nose !


Actually the J-Bend made by the Feed Tube, Burn Tunnel, and Heat Riser work just like the water trap under your sink preventing the flow of warm air to the outside .

If you are worried about it you can plan to cover the top of your Feed tube after every burn -this too can become Automatic .


If you are forced to use a fan to push air though your system to prevent smoke back then it is very easy to pull in too much air cooling the combustion zone . This also

Allows too much heat to escape up the chimney .

I and your fellow members can only make suggestions, based on observations and normal expectations of performance, you have the hard job, and we must have your

trust. Please keep posting here and we will help you solve your problems one by one until you are happy with your rocket . For the Crafts ! Big AL
 
proteas vryssas
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allen lumley wrote:You on the other hand are trying to retro-fit a Rocket Mass Heater RMH into an existing structure.

No, I don't. I had tear down completely the previous structure which was an open fireplace AND its chimney made of bricks.

allen lumley wrote:Notice the Amount of wood being burned. Here two bricks have been used to partially close off the Feed tube opening. This helps our fire in more than one way.
1) By Flowing Downward past the sticks of fuel wood it cools the sticks preventing smoke back!
2) as it flows through the fire the Air warms up and keeps the Firebrick that lines the Burn Tunnel and the Heat Riser Hot. Thus the proper Wood Fuel To Air Ratio keep excess air from cooling you combustion zone !
While we start with tinder and then kindling , we can fill the Feed Tube opening with small very dry wood and within 15 minutes have the walls of the Burn Tunnel glowing Red


I have been try to minimize the air of the feed tube with the same method with tight wood and with bricks on top of the feed tube. That didn't help.

Probably you don't see my photos because from these photos it is clear that no one are able to see the burn tunnel because all of his surrounding circumference (both the top-bottom and the sides) are build and enclosed with bricks and mortar. Thus the burn tunnel (which is in my case is a mold made of refractory cement) are not visible. Only the feed tube is visible which is outside of the house to keep the room quiet from the burning cracks and roars.

allen lumley wrote:Your best Tool to operate your Rocket correctly is your ears. When your rocket is running correctly you will be able to hear its roar !

Only on start of the fire I hear the roar. After a while the roar stops and it is barely audible from time to time. The roar is almost non existing except for the few minutes when I was start the fire.

allen lumley wrote:So- tell me again exactly what happens to your horizontal chimney from its ending through how many elbows or tees

There was only one tee were vertical chimney/pipe was meeting the horizontal pipe exhaust. That tee is outside the wall. My chimney is 90 inch tall.



I had already seen those photos from previous posts. They had connect dozens of barrels in series which they form the horizontal exhaust pipe until those barrels meet the chimney. I don't believe that inside of all those huge barrels no condensation ever occurs.

Please see the photo exhaust_pipes.jpg and quote one by one a specific sentence at a time if you don't understand my descriptions.
 
allen lumley
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Proteas Vryssas : I will be sending you a purple message ! Big AL
 
Glenn Herbert
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Unless you have a constant wind direction for the whole heating season, "lee/downwind" is not so important for you, as you really need to make your chimney to work well in any kind of wind. This means running it up to at least a meter above the peak of your roof, even if the peak is 3 or 4 meters away from the chimney.

It will be easier to support this chimney if it goes up inside the house and exits near the peak. This will also keep the chimney warmer and improve your draft, and lose less heat to outdoors.
There is no drawback to having a chimney inside a house except the space it takes. An internal chimney will pull no more heat out of the house than an insulated external chimney, and it will draw better in nearly all conditions. If you have any issue with losing room air while not burning, you can do what is a common practice and cover the feed tube with two bricks when the fire is out.
 
proteas vryssas
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Glenn Herbert wrote:Unless you have a constant wind direction for the whole heating season, "lee/downwind" is not so important for you, as you really need to make your chimney to work well in any kind of wind. This means running it up to at least a meter above the peak of your roof, even if the peak is 3 or 4 meters away from the chimney.

It will be easier to support this chimney if it goes up inside the house and exits near the peak. This will also keep the chimney warmer and improve your draft, and lose less heat to outdoors.
There is no drawback to having a chimney inside a house except the space it takes. An internal chimney will pull no more heat out of the house than an insulated external chimney, and it will draw better in nearly all conditions.


If I go straight up and make an internal chimney right near the barrel as it should be, then the chimney on the roof may distract the path of the drain which is 5-10cm near that internal chimney on the floor of the roof. Anyway I'll think your exhortation because it seem to me logical.


Glenn Herbert wrote:If you have any issue with losing room air while not burning, you can do what is a common practice and cover the feed tube with two bricks when the fire is out.

My feed tube and the ash pit under it, is outside the house as you can see from the pictures. My intentions for this, is to have a small short 1x1 sq.m shelter around the outside wall which will contain the feed tube, the chimney (which is next to the feed tube) and some of the woods to dry out.

Thus I can completely avoid :
a) any smell/odor from ash or wood burning inside the house,
b) any possibility of any long stick to get out/fell out the feed tube,
c) any crackling noise from the fire,
d) any smoke/back-drafting inside the house,
e) any dirt or bugs from the woods to go inside the house.

So, at the end the chimney would go "inside" but not inside the room I want to warm.

In the next few days I conduct more tests because the condensation/liquefaction of steam seems due the incomplete burning/bottleneck on top of the barrel which now I had to raise.
 
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