The UA-55 was designed by John Sargrove whilst he was at Tungsram. The all-stage valve was designed to work with the ECME automated radio production system.
The valve is basically a double beam tetrode with a common cathode but depending on connections and bias can operate in radio sections from RF, IF, Detector, AF amp, AF output and full wave rectifier. The heater is rated at 55 Volts and designed for series connected heater chains at 110 or 220 volts.
looking across the valve with the sections to the left and right of the centre line.
One of the anodes.
The connections. The heater passes into a wide oval cathode.
The top screen.
The construction in diagram form. Each half is screened from the other.
The electrodes in plan view. The grids have the windings aligned to reduce screen current. The E screen is the pair of beam plates.
Thanks to Matthew for sending the valve images.
The wide glass tube envelope is mm in diameter, and excluding the base pins is mm tall.
References: Data-sheet, Wireless World articles & 1040. Type UA-55 was first introduced in 1947. See also 1947 adverts.