As this system can be completly closed with valves, a pressure safety
valve had to be added. Its just a tube with another closed tube on top.
A small piece of rubber inside the tube to provide a seal.
The thermometer is in the middle of the top of the column, a perfect position.
In designing still heads, it seems to me that the positioning of the thermometer comes as an afterthought for a lot of people. I think it should be an intrinsic part of the design as it plays such a vital role.
I use rubber stoppers to place my thermometers. If you freeze the stopper, you can drill, shape and sand it with ease although your working time is short.