Abstract
IT will be recalled that about two years ago the ‘Catkin’ series of receiving valves was first produced in Great Britain (see NATURE, 131, 735; 1933). In the construction of this valve, the amount of glasswork was reduced to a considerable extent, the upper portion of the envelope being formed of the cylindrical copper anode, which was sealed to the lower glass portion by a vacuum-tight joint. Now, an entirely new series of literally all-metal receiving valves is announced by the General Electric Co. of America, and brief details of these were given by the New York representative of the Wireless World in the issue of that journal of April 19. These new valves employ a cylindrical outer shell of steel or iron welded to a metal base which rigidly supports the electrode system. The lead-in wires from the electrodes are strung through beads of glass, which are then placed in eyelets of a new alloy known as Fernico, which lines the holes in the base of the valve. The assembly is then passed through a gas flame which fuses the glass beads so that they fill the eyelets. Fernico is an alloy of iron, nickel and cobalt which has the same coefficient of expansion as the beads of glass employed, so that the seal is accom-plished without setting up strains in the fusing process. After the electrode system has been attached to the leads, the metal outer shell is placed over the structure and welded to the base. The valve is now exhausted through this metal tube, which is then clamped, welded and cut off at the appropriate time.
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All-Metal Radio Receiving Valves. Nature 135, 844 (1935). https://doi.org/10.1038/135844a0
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DOI: https://doi.org/10.1038/135844a0