GB642147A - Improvement in the processes for manufacturing electric discharge apparatus - Google Patents

Abstract

642,147. Discharge apparatus. SOC. ANON. POUR LES APPLICATIONS DE L'ELECTRICITE ET DES GAZ RARES, ETABLISSEMENTS CLAUDE-PAZ & SILVA. Sept. 19, 1947, No. 25601. Convention date, Sept. 21, 1946. [Class 39 (i)] In the manufacture of gas-filled electric discharge apparatus, such as a fluorescent lamp, comprising two main electrodes materially further apart than the width of the envelope of the apparatus, and at least one conductor, in entire or partial contact with the gaseous atmosphere and extending over a length materially greater than said width, which is designed to lower the starting voltage of the apparatus, and may comprise a strip of graphite deposited on the inner surface of the lamp envelope and extending close to the electrodes, difficulty in passing the normal direct or industrial low - frequency current discharge owing to emission of gas from said conductor, even if the apparatus has been previously degassed in the usual manner, is overcome by first passing a high-frequency current comprising damped waves, and preferably equal in magnitude to the normal discharge current. The high-frequency current may be obtained by connecting the lamp in series with a sparkgap across the capacitor shunted secondary winding of a transformer, and is passed through the final gas filling of the lamp for about 30 seconds, at any time before the first discharge of direct or low-frequency current. The lamp may then be run on a 50-cycle supply until it reaches its normal working characteristics.