How is the gas introduced into the glass tubing used in neon signs?

Answer:

Neon tubes are capped off by two glass electrodes that have wire passing from outside to inside. One of these electrodes has tubulation - a small tube which remains as a passage from outside to inside. Tubulations are sealed to a pumping system. The pumping system has glass stopcocks or valves that allow sections to be selectively opened or closed. An ultrahigh vacuum pump pulls air out of the tube while a high voltage transformer bombards and heats the remaining air - to produce temperatures in excess of 500ºF. This allows the tube to achieve a higher degree of purity. When a high vacuum is reached, and the tube begins to cool, a small amount of inert gas is introduced from a flask or a tank of pressurized gas. The tubulation is then heated and as it is pulled it such inward to make the tube's own seal. and wxngdygbu3gnxc32

First answer by ID2528147346. Last edit by Logundatbeast. Contributor trust: 0 [recommend contributor recommended]. Question popularity: 2 [recommend question].