Silica valves in wireless telegraphy

The paper discusses the construction for Naval purposes of wireless transmitting valves with silica envelopes. The main properties of silica as an envelope for high-power valves are enumerated and the valves are divided into two main classes depending on whether the anode heat is removed by radiation or by the use of a cooling fluid. A description is given of the electrode seals which have been developed to carry currents up to 100 amperes. The various types of valves and the methods of construction, evacuation and repair are described. The dimensions of standardized valves and the methods adopted for removing the heat generated in the various types of valve anodes are dealt with. The operating conditions for transmitting circuits and the methods of packing for transport are briefly referred to.