Wikipedia
Sun valve
A sun valve (Swedish: solventil, "solar valve") is a form of flow control valve, notable because it earned its inventor Gustaf Dalén the 1912 Nobel Prize in Physics.
The valve formed part of the Dalén light which was used in lighthouses from the 1900s through to the 1960s by which time electric lighting came to dominate.
Many prominent contemporary engineers, including Thomas Edison, initially doubted that the device could work. The patent office demanded a special demonstration before approving the patent application.