Stan, thanks for your reply. Don't know why the PVI files don't work. Strange. I'll re-upload them tomorrow at work.

I have to calculate the tubesheets this way. These are re-builts for existing heat-exchangers. Our client however has lost all information about the old exchanger except some rough sketches but he wants the new ones exactly the same.
I actually have to calculate them according to the Dutch RToD, but as these have less different situations for calculating tubesheets in comparison to ASME I already turned to ASME for the calculations.

I wanted to use 'configuration e' cause the channel is there and the pressure differences will be the same as in the 'configuration e' case. Only my channel will be more flexible. So adding a very flexible channel, and not looking at the channel results itself must give me a good impression of the needed tubesheet thickness I guess. The channel can be evaluated as a seperate pressure part.

I have troubles with adding the channel model correctly though. If anyone has any ideas or comments, feel free to respond. The files will be back online tomorrow (I hope).