Boiler Pump Control
The boiler would quickly run out of water if left unfilled. A large boiler with water is heavy, difficult to insulate, causes an explosion danger and takes a long time to warm up. For our design a small boiler must be used that is refilled.
Our design uses a double walled heat exchanger where hot oil flows around a central boiler pipe. The small boiler boils off the steam quickly and needs to be filled. It cannot be over filled which would flood the steam turbine. The boiler is under extreme pressure so all joints must be pressure tested.
Below are the pictures of my designs for controlling the boiler water pump. I ended up going with an internal measuring pipe inside the water boiler that measures the water level and temperature. In order to not have dynamic seals inside the pressure vessel I will be using two magnets to measure the water level through the pipe wall. One magnet ring will be attached to a float that will measure the water level in the boiler. Another magnet inside the centre tube (this is open to the atmosphere) will follow the magnet ring. When the flow reaches a lower lever the boiler feed pump will turn on and bring the level back to an upper level before turning off. In this way the boiler water lever will always remain within a certain range.
Preferred design, measuring pipe coming from the bottom
Alternate design measuring pipe coming from top