Electron emission cathode, esp. for electron beam welding gun - has conical support for cathode disc to reduce heat dissipation

摘要

An indirectly heated, electron emitter cathode assembly comprises a heating device and a cathode disc with fixing elements, mounted on a support having a hollow truncated cone shape, the edge of at least one of the bases of which is bent to form a lip or flange directed towards the interior of the cone. The cathode assembly is used esp. in an electron beam welding gun. The contact area between the cathode and the support and fixing elements can be reduced by a factor of four so that the power reqd. for heating the cathode can be reduced by a half while maintaining the cathode surface stable. Additionally, temp. gradients across the cathode are reduced so that uniform electron emission is obtd.