flue design on kettles

[simon]

I require some advice in designing a flue for a kettle (400L direct fired)
I want a flue which will not allow the bitter condensation to drip back into the wort, producing undesirable flavours, as is common practice in most brew kettles. What is the standard diameter for such a small kettle? I am thinking of a maximum of 150mm? Is this correct?

[Valleybrew]

The standard I have seen in most smaller kettle designs
is to first include a drip ring at the point the stack leaves the kettle. The ring catches any nasty drippings and allows them to drip out the side of the stack. I have this on my 7 BBL kettle but we still had problems with drip back so we installed a jog in the stack at 90 degrees horizontal over about 2 feet and then the stack cuts back at 45 degrees and up to the original vertical position and exits through the brewery roof. At the point where the horizontal running stack turns back vertical there is a catch basin with a drain to allow drip back to exit. If this is too confusing email me and I will send a photo, its a very inexpensive solution for a big problem.

Steve