The 7340 is also labelled CV140. It is a double signal diode. The two valves are completely separate flat structures separated by a plate screen. This clearly shows the signal usage, where it is important to keep RF isolation for vision and sound detection.
The thin sheet pair that forms the anode is formed into a top and bottom flange. These flanges pass through slots in the support micas and the assembly operator would then use a crimp tool to bend the tops slightly so that the flanges cannot be pulled back through the slots.
The small size of the diode sections with the larger central screen.
The diodes in close-up. The active region is the small central hollow cylinder formed by the two bright sheets of the anode.
The thin glass tube envelope is 18 mm in diameter, and excluding the B7G base pins is 48 mm tall.