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Description
Base of tube is labeled, "ML-298A Machlett Laboratories , Inc. Made in U.S.A. 262 Filament Volts for 35 Amperes Emission". A small label attached to the wooden crate reads: "Water Cooled Radio Tube. Paul Zoto, designer. Boston, Mass. Modified to increase power output to a constant 400 k. Radio waves penetrated plywood veneer and glue, drying both at a much faster rate than the steam method. This is very much like the radar oven used today." The Foothill Electronics Museum exhibit label for this tube reads: "The ML-298A is one of the largest triode vacuum tubes ever built. Designed by Bell Laboratories, it was originally manufactured by Western Electric and later by Machlet Laboratories of Springdale, Connecticut. The unique design features an external anode with integral water jacket and two glass envelopes, one at each end. The tungsten filament draws 225 amperes at 27 volts. Plate voltage can be as high as 20,000 volts and plate dissipation as much as 100 kilo-watts. At least 35 gallons of distilled water per minute is required to cool the anode. These tubes have been used for high power broadcast transmitters and as radio frequency generators for dielectric heating of the glue in plywood. Four such tubes were retrofitted into 120-kilowatt Radio Tunis by Voice of America engineers during World War II for propaganda service." Text from original Foothill Electronics Museum label: The ML-298A is one of the largest triode vacuum tubes ever built. Designed by Bell Laboratories, it was originally manufactured by Western Electric and later by Machlett Laboratories of Springdale, Connecticut. The unique design features an external anode with integral water jacket and two glass envelopes, one at each end. The tungsten filament draws 225 amperes at 27 volts. Plate voltage can be as high as 20,000 volts and plate dissipation as much as 100 kilowatts. At least 35 gallons of distilled water per minute is required to cool the anode. These tubes have been used for high power broadcast transmitters and as radio frequency generators for dielectric heating of the glue in plywood. Four such tubes were retrofitted into 120-kilowatt Radio Tunis by Voice of America engineers during World War II for propaganda service.
Type
image
Identifier
96CF0A79-F1F1-46BC-999B-346510825583 2003-1-243
Subject
Triodes (LCSH) Vacuum-tubes (LCSH) World War, 1939-1945--Communications Radio--Transmitters and transmission (LCSH) Radio frequency (LCSH)
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