Low pressure mercury vapour discharge lamp

摘要

A compact fluorescent electric lighting unit has a U-shaped tube and one end (2a) has an inset pumping tube (5). During the evacuation and filling of the discharge U tube the ends of the pumping tube are open. A solid element of iron (6) is held in place with the aid of an external magnet and an amalgam or liquid mercury (8) is introduced. After filling with the inert gas the magnet is removed so that the iron or amalgam moves to the discharge end of the pumping tube. The end of the pumping tube is sealed by heating and squeezing together.