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Post by fasardi on Jun 5, 2019 4:35:11 GMT -8
Hi, i`m planning my stove (again) since it will be placed in other room... My idea is to have a double bench, since i have to put the stove in a certain place it will be neccesary to have two benches, one with the exit chimney. I will put a galvanized iron sheet as a deflector to force the flue in the blind bench, and maybe make this one a little taller and with the floor 10 cm higher than the other bench to help the flue go to the chimney. Don't know if this it's really neccesary
I was wondering too if the size of the bench is right, the blind side's section is 35 cm width, 60 cm height, and 3.5 meters long. The other side it's 35cm width, 50 cm height and 3.8 meters long. All measures are internal. The total area of the bell is about 14 m2 so it's ok, but don't know if the benches measures are ok, and if the inspection doors are well placed. I'm planning on making a 5 minute riser, but i don't know if it will be necessary to make a removable cover for easy replacement...
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Post by esbjornaneer on Jun 6, 2019 3:30:46 GMT -8
One way to think of how the gasses will behave (repeated from other places) is to turn the drawing upside down and think of how it would behave if it were a (funny shaped) bathtub that you filled with water (from the port of the firebox/heat riser), then letting the water flow out via the overflow exit, the exit being the chimney pipe. When you think of the water analogy you will realise that there is no need to have different height floor level (the water will not be in contact with the floor as it runs out when it reaches the height if the entrance to the chimney).
For a calculation of the ISA: you need to include all the surfaces that were in contact with the 'water', see above. So you need to add the internal walls of the 'tower' section holding the heat riser to the internal of the benches. And as the chimney will not sit flat with the floor of the bench you need to know the distance from the floor to the chimney pipe opening (as it will not be in contact with the water, as above).
I can not see that a deflector is ever needed within a bell structure, but correct me anyone.
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Post by fasardi on Jun 6, 2019 4:49:17 GMT -8
Thanks for the weird bathtub analogy! if it's correct, a deflector will be useless if i make the blind bench taller than the other bench, and maybe it won't be necessary, but just to be sure both benches work i think i will. Checking Batchrocket.eu i saw a construction with two benches and a deflector, i thought the chimney was in one of the benches, and it turned out i was wrong, it was behind the core. In that stove a deflector was used. Cul de sac Batchrocket
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Post by josephcrawley on Jun 6, 2019 6:13:51 GMT -8
If you place the chimney at the end of the bench be sure and have a good way to preheat the pipe otherwise cold starts will be a very smokey affair.
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Post by esbjornaneer on Jun 6, 2019 6:48:36 GMT -8
I agree with Joseph about the chimney! And make sure it is taller than the tallest object in the near area to make it draws well. Seeing the deflector in the .skp- link of the stove I understand what you mean. What it does is that it makes the overflow/chimney look like the lowest contour of the deflector, the rest of the board being sealed against the inside of the bell. So instead of having an overflow/chimney that starts at 319mm above floor level it starts at 135mm, thereby gaining 185mm of 'water' touching height (this makes a big difference in ISA as it is times the circumference at that level of the total bell space (tower+ both benches).
A deflector like that placed instead between the bench that the chimney exits from and the tower and first bench would make it behave as a double bell. First filling tower and first bench before spilling into second bench then into the chimney. It would mean that the total ISA needed to be smaller as a double bell is more efficient at extracting heat than a single bell. More on this in other threads.
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Post by fasardi on Jun 7, 2019 5:00:52 GMT -8
If you place the chimney at the end of the bench be sure and have a good way to preheat the pipe otherwise cold starts will be a very smokey affair. Yes, i have placed an inspection cover (cover? lid?) right down the chimney to preheat the pipes.
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Post by fasardi on Jun 7, 2019 5:08:44 GMT -8
I agree with Joseph about the chimney! And make sure it is taller than the tallest object in the near area to make it draws well. Seeing the deflector in the .skp- link of the stove I understand what you mean. What it does is that it makes the overflow/chimney look like the lowest contour of the deflector, the rest of the board being sealed against the inside of the bell. So instead of having an overflow/chimney that starts at 319mm above floor level it starts at 135mm, thereby gaining 185mm of 'water' touching height (this makes a big difference in ISA as it is times the circumference at that level of the total bell space (tower+ both benches).
A deflector like that placed instead between the bench that the chimney exits from and the tower and first bench would make it behave as a double bell. First filling tower and first bench before spilling into second bench then into the chimney. It would mean that the total ISA needed to be smaller as a double bell is more efficient at extracting heat than a single bell. More on this in other threads.
I think i'll go without a deflector, because now the bell bench is covering one of the walls of two rooms, and i need it to be that way. And the ISA is ok!
Thanks to everyone! hopefully in a couple months i'll post some pictures of the stove!
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