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1946 - Dr. Norman C. Beese assures a desired vacuum 1,000 times better with the mercury diffusion pumping system


CD 1963070 E&MP 25.003

Electric Lamps

SEP 14 1946

This mercury diffusion pumping system, laboratory prototype of a lamp manufacturing technique, assures a desired vacuum 1,000 times better than by mere mechanical pumping.

Against a backdrop of wall piping and glass tubing, Dr. Norman C. Beese, Westinghouse research engineer who studies lamps for light output and efficiency, is shown sealing off the inner bulb of an experimental mercury vapor lamp by gas flame. Argon gas and mercury were introduced into the bulb, which previously was exhausted through the glass tubing with the help of a liquid air trap to freeze out unwanted water and mercury vapor.

Top efficiency of high intensity mercury vapor lamps is attained by high pressures created inside the bulb-within-a-bulb. There is 1,500 pounds per square inch pressure, 100 times the pressure of free air, in some high wattage lamps.

Original Caption by Science Service

National Museum of American History


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