GB957023A - Improvements in high pressure gaseous discharge lamps - Google Patents

Abstract

957,023. Discharge lamps. PATENTTREUHAND-GESELLSCHAFT FUR ELECTRISCHE GLUHLAMPEN m.b.H. July 19, 1960 [July 22, 1959], No. 25124/60. Addition to 880,422. Drawings to Specification. Heading H1D. A rare gas-mercury vapour discharge lamp for continuous operation in which the electrode distance amounts to at least double the inside diameter of the envelope comprises an envelope of quartz or other transparent material of temperature resistance similar to quartz and which for the purpose of obtaining a wellstabilized discharge has a filling pressure of gas, reduced to a lamp without dead space, lying between 5 and 350 mm., preferably between 20 and 200 mm., and which when the lamp is operated without artificial cooling at a low voltage gradient of less than 30 volts/cm. of electrode distance and at a current density of less than 100 amps/cm.<SP>2</SP> of envelope crosssection has an input concentration between 5 and 200 watts/cm.<SP>3</SP>, preferably between 10 and 80 watts/cm.<SP>3</SP>, of envelope volume, the filling containing also an amount of mercury in the range of 0.01 to 0.7 mgrms. per cm.<SP>3</SP> of envelope volume whereby the current density of the discharge amounts to more than 2 amps. per sq. cm. of envelope cross-section. The relation between the filling pressure and the reduced filling pressure of a lamp without dead space is given in the parent Specification. In a specific example the envelope has a diameter of 30 mm., a filling of xenon at a pressure of 100 mm. corresponding to a reduced pressure of 70 mm., a filling of 0.2 mmgrs. of mercury per cm.<SP>3</SP> corresponding to a mercury operating pressure of about 200 mm., an arc length of 120 cm., an arc loading of 170 watts/cm., and a current density of 6 amps/cm.<SP>2</SP>.