54mm/2" Bokakob on a Grainfather 2kW boiler
Posted: Mon May 20, 2024 2:35 am
No new designs here, I don't think, but I would appreciate any feedback or more experienced eyes on my plan for a Bokakob still please 
.
I have spent a lot of time reading around these forums and more faffing about in Autodesk software, but really feel ready to get on with the build now.
I have about 1.6metres (5' 3") of clearance from top of boiler to ceiling. I plan for the condenser & takeoff section to be about 32cm (3.6") and the packed column a little more than 1metre (3'3"), I think 1.2m is the max I can get to in the space, so I will use as much as a can. The rest of the space is taken up with the height of a tri clamp boiler lid, cooling hoses at top and clearance space.
I am intending to use 2" tri clamp ferrules, soft soldered to the main tube, so I can break apart the lid, main column and head sections. The designs I have so far shown below; (the grey bits at the top of the column represent John Guest push-fit fittings that I have to hand from the beer brewing side of things)
I am planning a dual coil condenser which would comprise 2 coils of 6mm OD tube fed from a 10mm coldfinger. The coil height is about 15cm (6"), with 15 turns on each. That ends up at about 2.5m of copper in the coil, which seems less than the usual, but sounds like it should be sufficient for a 2kW boiler (I am trying to keep the condenser as short as possible to maximise my main column height).
I have a 25mm (1") vertical gap between slant plates, not a lot of clearance between the take off tube and ferrule, but I don't think that will be a problem for soldering or operation?
The take off and thermometer ports are 10mm OD tube, because that is what I have to hand, also I can turn down and drill a 12mm diameter PTFE rod that I have, to create a tight seal around a thermometer probe.
I think there will be enough space below the plates, opposite the take off tube so that at a later point I could insert a 1" port and add a VM path
I am not sure how much or what packing to use, maybe stainless steel scrubbies with some copper ones near the top. The insulation I have is only 13mm (1/2") thick, polyethylene which might be a little thin or may not handle the column temperature, I don't think the column should get above 105ºC (221°F) should it?
I would really appreciate any feedback or suggestions on this - I hope it looks like a viable plan
thanks!
. I have spent a lot of time reading around these forums and more faffing about in Autodesk software, but really feel ready to get on with the build now.
I have about 1.6metres (5' 3") of clearance from top of boiler to ceiling. I plan for the condenser & takeoff section to be about 32cm (3.6") and the packed column a little more than 1metre (3'3"), I think 1.2m is the max I can get to in the space, so I will use as much as a can. The rest of the space is taken up with the height of a tri clamp boiler lid, cooling hoses at top and clearance space.
I am intending to use 2" tri clamp ferrules, soft soldered to the main tube, so I can break apart the lid, main column and head sections. The designs I have so far shown below; (the grey bits at the top of the column represent John Guest push-fit fittings that I have to hand from the beer brewing side of things)
I am planning a dual coil condenser which would comprise 2 coils of 6mm OD tube fed from a 10mm coldfinger. The coil height is about 15cm (6"), with 15 turns on each. That ends up at about 2.5m of copper in the coil, which seems less than the usual, but sounds like it should be sufficient for a 2kW boiler (I am trying to keep the condenser as short as possible to maximise my main column height).
I have a 25mm (1") vertical gap between slant plates, not a lot of clearance between the take off tube and ferrule, but I don't think that will be a problem for soldering or operation?
The take off and thermometer ports are 10mm OD tube, because that is what I have to hand, also I can turn down and drill a 12mm diameter PTFE rod that I have, to create a tight seal around a thermometer probe.
I think there will be enough space below the plates, opposite the take off tube so that at a later point I could insert a 1" port and add a VM path
I am not sure how much or what packing to use, maybe stainless steel scrubbies with some copper ones near the top. The insulation I have is only 13mm (1/2") thick, polyethylene which might be a little thin or may not handle the column temperature, I don't think the column should get above 105ºC (221°F) should it?
I would really appreciate any feedback or suggestions on this - I hope it looks like a viable plan
thanks!