woodduck wrote:andybear wrote:While those slots on the vapour trap look cool they actually make the trap depth even more shallow. The trap depth has to be deeper than the tray/bath depth. :handgestures-thumbupleft:
I'm not trying to argue, I'm just trying to understand the science. Why does the downcomer bath need to be deeper than the plate bath depth? Isn't the downcomer bath just there to stop vapour going back up the downcomer? How does the plate depth affect the downcomer?
I don't think it matters, it's just the same as when syphoning. In syphoning, it's the difference in heights of the two levels of fluid that matter, so long as the fluid level coming down the downcomer tube is higher than the lowest point of the downcomer cup (as in the point where the fluid spills over and out of the cup) then there will be a positive pressure that the vapour coming up from the boiler or a lower plate will not be able to overcome.
In syphoning it does not matter how deep your two vessels are, it matters that the two fluid levels are different.
Downcomer tubes need to be a certain diameter for the amount of fluid that is flowing down the column from the RC. If the downcomer is too wide then the fluid will simply go down the sides of the downcomer and not form a bath until right at the bottom. Or if they are too narrow there will be a deep bath formed but the fluid takes too long to go down and the plate above floods.
I'm guessing that downcomer cups that are too deep might suffer some smeering as the replenishment of fluid in them takes a long time.
Just my 2 c.