A 125 mm batch heater in France
Oct 26, 2016 2:31:59 GMT -8
pinhead, AlexHarpin, and 1 more like this
Post by Deleted on Oct 26, 2016 2:31:59 GMT -8
Hi all, I'd like to share with you a build I made in July. It was part of a small workshop I organised in Ardèche, France.
The core is a 125 mm batch deeper than nominal — 40 cm instead of 36. The whole heater is 1,4 m high. The internal surface area is 3 m2 (the surfaces under the top of the opening of the bell stack are not taken into account). The first skin and the core required approximately 180 refractory half-bricks measuring 22x11x3 cm. The second skin required approximately 190 adobe half-bricks measuring 5x10x20 cm. Total weigh is approx. 700 kg and power is close to 1,2 kW considering two fires a day and a global efficency of 80%. One can put approx. 4 kg of wood per load. The part between the exterior wall and the first skin is insulated with vermiculite.
We tried to do as much as we could by ourselves. The fireplace door, the soot door, the damper and the floor channel were welded during the workshop. The first skin is made of refractory half-bricks that are 3 cm thick. The second skin is made of raw earth (adobe) bricks made with earth from the garden and sand from the river. They are ready to be used after two days of drying. A team of two can make between 300 and 400 of these per day. In between there is cardboard as an expansion joint.
The refractory mortar is made with local white-blue clay and also local screened pozzolan with some very fine refractory grog. The clay has been purified by sedimentation in a cement mixer — it is left overnight in a large container with water. When the clay is well hydrated, it is mixed in a cement mixer and then left to wait for a few minutes. The large particles will sink and a mix of clay and water can be poured in a container.
The clay mortar has been dug from a local source. The proportions of clay and sand were already good so we just had to screen it to 0-2 mm.
On the top of the heater there is some sort of earthen floor : earth, sand and horse manure. There was too much water in the mix and the drying was too fast so cracks appeared. They have been repared with the same mix.
Under the floor there are timber beams that are not shown in the pictures. Under the heater are cellular concrete slabs.
There is no bypass valve, which is an error. The stack is not excellent neither : 3,5 m high from the top of the heater to the end of the stack. The lower half inside the house is uninsulated, the other half is insulated.
The surface of the opening of the bell is 2,7 times the CSA of a 125 mm batch. The heat riser is made of two layers of insulated sleeve with an inside diameter of 120 mm. In between the two layers is a mix of vermiculite and clay. We used KALMIN 50 sleeves made for copper alloys and for temperature under 1200°C.. this is NOT enough. It stays in place but in other experiments i've seen cracks appearing. Happily in this heater nothing has happened yet but i will not use this kind of sleeves anymore. Flames contact require better materials.
We did measures with the Testo 330-LL while the heater was not completely dry (adobe bricks take a long time to dry because they are raw) and the exterior temperature close to 30°C.. not the best experimental setup ! Other measures will be made this winter.
The heater has been in daily use for a month now. Users are very happy with it. At the beginning there was very little heat coming from the heater, probably because of the firing of the adobe bricks and the inertia of the 80 cm stone walls. After a week of use the heater was functioning normaly and now it can stay noticeably warm for 24 hours if the shut-off valve is closed.
It is used to heat a 30 m2 stone house (in fact a part of a larger house being rebuilt), leaky and not very well insulated. I would say the heater is a bit small for this house. The problem is that single bells are too large. I'm currently building a double bell system and will post results.
Pictures can be found here : webcloud.zaclys.com/index.php/s/2Dybhv24uI0vDna
Sketchup for the version 8 : webcloud.zaclys.com/index.php/s/qfZ1ehC9B9ugOGd
Sketchup for the 2016 version : webcloud.zaclys.com/index.php/s/XPZmLuGJJeuDRTi
The core is a 125 mm batch deeper than nominal — 40 cm instead of 36. The whole heater is 1,4 m high. The internal surface area is 3 m2 (the surfaces under the top of the opening of the bell stack are not taken into account). The first skin and the core required approximately 180 refractory half-bricks measuring 22x11x3 cm. The second skin required approximately 190 adobe half-bricks measuring 5x10x20 cm. Total weigh is approx. 700 kg and power is close to 1,2 kW considering two fires a day and a global efficency of 80%. One can put approx. 4 kg of wood per load. The part between the exterior wall and the first skin is insulated with vermiculite.
We tried to do as much as we could by ourselves. The fireplace door, the soot door, the damper and the floor channel were welded during the workshop. The first skin is made of refractory half-bricks that are 3 cm thick. The second skin is made of raw earth (adobe) bricks made with earth from the garden and sand from the river. They are ready to be used after two days of drying. A team of two can make between 300 and 400 of these per day. In between there is cardboard as an expansion joint.
The refractory mortar is made with local white-blue clay and also local screened pozzolan with some very fine refractory grog. The clay has been purified by sedimentation in a cement mixer — it is left overnight in a large container with water. When the clay is well hydrated, it is mixed in a cement mixer and then left to wait for a few minutes. The large particles will sink and a mix of clay and water can be poured in a container.
The clay mortar has been dug from a local source. The proportions of clay and sand were already good so we just had to screen it to 0-2 mm.
On the top of the heater there is some sort of earthen floor : earth, sand and horse manure. There was too much water in the mix and the drying was too fast so cracks appeared. They have been repared with the same mix.
Under the floor there are timber beams that are not shown in the pictures. Under the heater are cellular concrete slabs.
There is no bypass valve, which is an error. The stack is not excellent neither : 3,5 m high from the top of the heater to the end of the stack. The lower half inside the house is uninsulated, the other half is insulated.
The surface of the opening of the bell is 2,7 times the CSA of a 125 mm batch. The heat riser is made of two layers of insulated sleeve with an inside diameter of 120 mm. In between the two layers is a mix of vermiculite and clay. We used KALMIN 50 sleeves made for copper alloys and for temperature under 1200°C.. this is NOT enough. It stays in place but in other experiments i've seen cracks appearing. Happily in this heater nothing has happened yet but i will not use this kind of sleeves anymore. Flames contact require better materials.
We did measures with the Testo 330-LL while the heater was not completely dry (adobe bricks take a long time to dry because they are raw) and the exterior temperature close to 30°C.. not the best experimental setup ! Other measures will be made this winter.
The heater has been in daily use for a month now. Users are very happy with it. At the beginning there was very little heat coming from the heater, probably because of the firing of the adobe bricks and the inertia of the 80 cm stone walls. After a week of use the heater was functioning normaly and now it can stay noticeably warm for 24 hours if the shut-off valve is closed.
It is used to heat a 30 m2 stone house (in fact a part of a larger house being rebuilt), leaky and not very well insulated. I would say the heater is a bit small for this house. The problem is that single bells are too large. I'm currently building a double bell system and will post results.
Pictures can be found here : webcloud.zaclys.com/index.php/s/2Dybhv24uI0vDna
Sketchup for the version 8 : webcloud.zaclys.com/index.php/s/qfZ1ehC9B9ugOGd
Sketchup for the 2016 version : webcloud.zaclys.com/index.php/s/XPZmLuGJJeuDRTi
