Gas discharge lamp with a cathode shield, germicidal lamp comprising the same and method of disinfecting contaminated water or treating wastewater and increasing current load in a gas discharge lamp

摘要

A conductive cup (26) is placed around an electrode or a filament (22). The cup (26) is covered with an insulator material (30) having a hole (32) therein. The diameter of the hole (32) in the cover has a proportional relationship to the diameter of the envelope (14) of the lamp (10) and the diameter of the cup (26). The ratio of the diameter of the envelope (14) and the hole (32) in the cover preferably ranges between 3.5 and 4.5. The ratio of the diameter of the cup (36) and the hole (32) in the cover preferably ranges between 2.0 and 3.0. It has been determined that these ratios improve current loads without changing discharge characteristics. Additionally, lower temperature operation and starting is facilitated with increased service life. The cathode shield is particularly applicable to germicidal lamps used in water treatment due to the lower starting and operating temperatures required.