Abstract:
A replenishable gas discharge tube comprises a plurality of closed cells within the tube envelope, each cell containing a quantity of the ionizable gas, and means operable from outside the tube envelope for successively opening the cells to release the gas within the envelope. In one form of the invention, a plurality of pins are appropriately arranged within the tube envelope, which comprises a gas-tight bellows. The pins are caused to successively puncture the covers of the closed cells by increasing the engagement of two threaded members engaged outside the envelope, which movement is permitted by the bellows.