The CV2190 is a Heil tube microwave oscillator valve. The prototype for the CV specification was the V233A/1K.
Heil Tubes were made in the UK by STC.
Like the Klystron the Heil tube is a velocity modulated device. Unlike the klystron the Heil Tube employs magnets to assist the electron beam. The flange is 41 mm in diameter.
The central copper resonating tube has slots for the electron beam to enter the cavity. The heater/cathode is in the centre of the image and carries the code 35FN.
The electron source is on the right with the grey anode on the left. The copper resonator is in the centre.
The thin glass tube disc seal envelope is 19 mm in diameter and, excluding the B7G base pins, is 58 mm tall.
Reference: Data-sheet. Type CV2190 was first introduced in 1955. See also1955 adverts.