I didnt give up on it and combined some ideas from a conventional plate still etc.
1. introdced a overflow tube for liquid to drain down to the next level
2. angled the entire tube at 45deg to increase bubble travle through liquid.
3. the plates slots are cut at 90deg to tube, were the plate is inserted and brased in place to simplify manufacture, there is no need for making bolt together sections.
4. perferated the top plate from the middle down in each section to create more smaller bubbles instead of one big bubble which violently splased around in tube..
5. placed reflux coil at outside top of colum " this can be changed to suit"
I have made a model out of acrylic and tested it with compressed air and the theory works well.
I am in the process of making a full working unit, but here is a computer model with only 4 plates shown.
Obviously it can be made with any number of plate sections.
I am eager to hear comments on any faults or drawbacks that i may have overlooked.
I will locate and replace the pics....