Improvements in or relating to devices comprising artificially-cooled high-pressure mercury-vapour discharge tubes

摘要

471,321. Mercury vapour lamps. NAAMLOOZE VENNOOTSCHAP PHILIPS' GLOEILAMPENFABRIEKEN. May 24, 1937, No. 14440. Convention date, May 27, 1936. [Class 39 (i)] An artificially-cooled high-pressure mercuryvapour discharge lamp supplied through series impedance is so dimensioned and the impedance and supply voltage so chosen that the load per unit length of tube exceeds 400 watts per cm., the current exceeds two amperes, the voltage drop per unit length of the discharge path is less than 300 volts per centimetre and the mercury-vapour pressure during use is above 10 atmospheres ; preferably also the current in amperes is between À05 Gd/175 and 2Gd/175, where G is the voltage drop per centimetre of discharge path and d the internal diameter of the tube in mm. ; this arrangement is stated to yield a more yellow light and a wider luminous discharge path than the ordinary forms. The Figure shows such a tube 1 with an external diameter of 7À8 mm. and an internal diamter of 5 mm., enclosed in a casing 5 through which water can be passed. The ends of the tube are constructed as shown, and contain mercury from which the ends of the tungsten leads 2, 3 project slightly, being 1 cm. apart. The tube contains argon at a pressure under ordinary temperature of 40 mm. of mercury. Several numerical examples are given.