A Giant Valve

Radio Record, Volume IV, Issue 25, 2 January 1931, Page 2

A Giant Valve

For New American Transmitter F the innovations introduced inco the new transmitting station of KDKA, which is being built near Saxonburg, Philadelphia, is the new 200kilowatt valve, a photograph.of which appears on page 1. This valve is not merely an enlarged edition of a smaller one, but is thoroughly engineered as a valve of larger size and of a distinctly novel design.. The new valve, called the AW220, is 72 inches in height, has a diameter of eight inches, and weighs 60 pounds. in its design engineers ‘found one of their greatest problems to be that of cooling the grid. An idea of the problem 7 "

which was eventually overcome may be obtained from the statement that approximately five tons of cooling water must be passed through the water jacket each hour it is in operation. This water cools the valve in the same manner as water in a motor-car cools the motor. One hour’s operation of the valve would heat enough water to supply the domestic requirements of the average home for several weeks. While AW-220 valves will only be used to generate high frequency power for tadio stations, an appreciation of the power capacity of one of these valves can perhaps best be gained by a comparison with familiar. household devices. For example, a similar amount of power of the kind distributed commercially would operate simultaneously four hundred toasters or flat irons. This would also be the equivalent of power required to light one thousand average homes of five to six rooms, or the energy to operate two modern street cars.