The NT32B is a British Navy transmitting triode designed for HF (short wave) use.
The lettering is moulded into the silica in the same way as the Mullard TYS5-3000 and silica valves were made by either Mullard or GEC for the British Armed Services.
This exhibit is complete with its mounting frame.
The picture shows the frame from the rear and below is a close-up of the sturdy copper contacts attached to the rear of the frame.
The anode is of basket weave construction and appears as treated nickel. The dull surface would make a better radiator of heat than a bright nickel cylinder.
In this picture the grid spiral can be seen inside the anode. The longitudinal supports are also visible.
The silica envelope is attached to the mounting frame with metal strips that fit into a buckle. The asbestos tape to insulate the fixing is also shown.
In the final picture the method of connecting the electrodes to the outside world is seen. The tubes are filled with lead and the lead seals to the silica. The lead seals also set an upper limit to the working temperature of the envelope.
The silica tube envelope is 95 mm in diameter and, overall is 535 mm tall.
