The TYS5-2000 is displayed in the John Lawrence collection in its original wooden case and complete with guarantee card. The envelope is of silica and the connections are via flexible copper braid fixed to the valve.
The photograph just shows the helical grid within the long cylindrical anode. The silica envelope is indicative of high dissipation and a high working temperature.
Some applications were not suited to the use of the external anode valves and here the very expensive silica envelope became a viable option. This valve type was designed for industrial heating applications and would deliver 6 kW of RF at up to 20 MHz.
We have a smaller version of this construction (SL2-787) and it has the filaments strung between two plates in the shapes of crosses. This gives eight lengths of filament running down the length of the valve.
The interesting thing about this exhibit is that it looks as though it is one of the M-OV-designed types, with typical M-OV lead-out seals. So it is possible that the crate and guarantee card do not match the actual valve.
The silica tube envelope is 108 mm in diameter and 406 mm long.
References: Data-sheet. Type TYS5-2000 was first introduced in 1960.
Absolute Maximum Operating Conditions¶
Updated August 03, 2020. shape:silica.tube construction:silica.to.metal type:triode base: pin: