After long thought and looking at buildup on atomizer coils it was time for some serious rethinking.
When air passes a cylinder it doesn't wrap all the way around it. It turbulates on the back side. This presents a problem for the coil, the thermal mass, only getting just over 50% exposure. Doesn't seem like the most efficient design. It's small diameter is to its advantage, but the weight of the atomized liquid is heavier and its energy will pull it past the coil not allowing it to roll back in to it.
Ceramic cups sometimes have side intakes allowing more disturbance of the atomized liquid. This can cause a stall, possibly holding it near the coil, allowing it to vaporize. With the diameter of the PV tube, it seems doubtful. It's possible that this design doesn't matter
being small tubed and hit from all directions but the other advantages made below should be well founded.
The new design here is an oval shape. An egg (small end 1st) is actually the best for less aerodynamic drag.
The oval design has less resistance to airflow, (Airplane Airfoils)
Less distance from the coil as it passes and less distance to try and be pulled back in. Its biggest plus is more surface area of the nichrome wire exposed to the atomized airflow. Approximately 80%.
Other advantages is the main body of the coil is now in the mainstream of the 2 bottom feed holes and the 2mm "side face" is in direct path of the side inlets. A single smaller dia coil can be 2x as wide as the feed ports. When examing a dead carboned atomizer, it's normally buldged in the middle and very little to none on the ends since the ends were out of the airstream not really doing any work.
Materials were 2ea. 1mm rods as a winding core and 1.25in of 36ga wire. Resulting in a 3.1ohm coil. This makes a coil 1mm wide x 2mm tall at its widest points plus the dia of the wire. (.005 in.)
My next one will use a 1.5mm top rod to more simulate the egg shape.
As for now, not much to say other than it works well. Vapor production is good and time will tell on buildup and longevity.
Note: The 801 high bridge atty pictured had a broken mesh leg. Best attempts were made to repair the mesh joint and assure good feed on that side. So far I haven't noticed any problems. No typical 801 flooding, but it's still early on this one. Maybe a reduced feed on the bad side or the design allows it to just get drawn out.
Hope you enjoy it.
Edit:
Silica "fire wick" rope: McMaster-Carr
Due to changes at McMaster Carr be sure to select option #3 or #4 for the silica rope. If not selected you will receive a lower temp fiberglass rope.
Nichrome wire: 36ga (27ohm per ft) $2 for 10' free shipping from:
Nichrome Wire
When air passes a cylinder it doesn't wrap all the way around it. It turbulates on the back side. This presents a problem for the coil, the thermal mass, only getting just over 50% exposure. Doesn't seem like the most efficient design. It's small diameter is to its advantage, but the weight of the atomized liquid is heavier and its energy will pull it past the coil not allowing it to roll back in to it.
Ceramic cups sometimes have side intakes allowing more disturbance of the atomized liquid. This can cause a stall, possibly holding it near the coil, allowing it to vaporize. With the diameter of the PV tube, it seems doubtful. It's possible that this design doesn't matter
being small tubed and hit from all directions but the other advantages made below should be well founded.
The new design here is an oval shape. An egg (small end 1st) is actually the best for less aerodynamic drag.
The oval design has less resistance to airflow, (Airplane Airfoils)
Less distance from the coil as it passes and less distance to try and be pulled back in. Its biggest plus is more surface area of the nichrome wire exposed to the atomized airflow. Approximately 80%.
Other advantages is the main body of the coil is now in the mainstream of the 2 bottom feed holes and the 2mm "side face" is in direct path of the side inlets. A single smaller dia coil can be 2x as wide as the feed ports. When examing a dead carboned atomizer, it's normally buldged in the middle and very little to none on the ends since the ends were out of the airstream not really doing any work.



Materials were 2ea. 1mm rods as a winding core and 1.25in of 36ga wire. Resulting in a 3.1ohm coil. This makes a coil 1mm wide x 2mm tall at its widest points plus the dia of the wire. (.005 in.)
My next one will use a 1.5mm top rod to more simulate the egg shape.
As for now, not much to say other than it works well. Vapor production is good and time will tell on buildup and longevity.
Note: The 801 high bridge atty pictured had a broken mesh leg. Best attempts were made to repair the mesh joint and assure good feed on that side. So far I haven't noticed any problems. No typical 801 flooding, but it's still early on this one. Maybe a reduced feed on the bad side or the design allows it to just get drawn out.
Hope you enjoy it.
Edit:
Silica "fire wick" rope: McMaster-Carr
Due to changes at McMaster Carr be sure to select option #3 or #4 for the silica rope. If not selected you will receive a lower temp fiberglass rope.
Nichrome wire: 36ga (27ohm per ft) $2 for 10' free shipping from:
Nichrome Wire
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