Stahlgekapseltes Quecksilberdampf-Entladungsgefäss

1,005,346. Discharge apparatus. BROWN, BOVERI & CO. Ltd. March 28, 1963 [March 30, 1962], No. 12274/63. Heading H1D. In a steel-capsuled mercury-vapour discharge vessel, the vapour pressure is regulated by an envelope 6 extending from anode 1 to cathode 2 so that no direct vapour flow can reach the vessel wall 4 from the cathode. The envelope is perforated, the size and distribution of the perforations being such that the pressure inside the screen remains nearly constant. The cathode may be either connected electrically to the wall, or insulated therefrom. The envelope may be connected to the wall through thermal insulator 10, or may be electrically insulated therefrom by ring 3. In another arrangement, the envelope is supported by a stay on the wall, Fig. 2 (not shown). In a multi-anode vessel, a single envelope extends from the cathode, a vapour dome, and all the anodes, Fig. 3 (not shown). The apertured envelope may comprise strip-formed surfaces 16 with cross-pieces 17, 18. Alternatively, the envelope shell may comprise a perforated plate, honeycomb plate, or wire gauge. The envelope may be used as a lead to an exciter anode 11. A de-ionizing grid 8 may be connected to the shell and supported thereby.