The HL10 is a high voltage triode designed for use as a voltage regulator for EHT circuits. This valve was donated by Liverpool University and had been used in medical/biological analysis equipment.
The construction follows the pattern of modern power devices with a grid cage around an indirectly heated cathode. See alsoQV1-150A. Looking into the valve, the top of the grid cage is a solid disc. In view of the high voltages it is designed to work with the grid to anode separation is considerable. The physical structures are held in place with clamps around the pinch stem and anode tube. This is expensive hand assembly.
Another view showing the grid clamped to the pinch stem.
The grid cage is made with gold plated wires.
The underside of the grid support showing the gold plated wires of the grid cage. The ceramic insulation holds the base of the cathode tube and within are the insulated heater wires.
The packaging of these professional valves was rather special. The outer box was made with very strong board and not corrugated card. The outer dimensions are: 375 x 270 x 190mm.
The outer box with the original seal broken for the first time.
Opening the box reveals the valves vacuum packed onto an inner corrugated card sleeve. This places the delicate glass well away from any outer wall.
The inner sleeve is 600 x 535mm and has a thick polythene bag bonded to it. When folded the sleeve is 357mm wide.
The inner sleeve with the valve held against a foam block.
The reverse of the inner sleeve showing how the top and bottom of the card has been folded for extra strength.
The valve in its local packing. The strip running the length of the valve is designed to aid the release from the packing.
The English instructions from the multi language sheet.
The wide glass tube envelope is 60 mm in diameter, and IO excluding the base pins is 230 mm tall.