||This is a low pressure mercury lamp with a discharge tube fabricated from quartz to allow a high transmission of UVC radiation. The discharge tube is bent into a U-shape both for compactness and to increase the UV energy density over a given surface area. The lamp operates from a standard 10-watt fluorescent tube choke, with no auxiliary starter being required. Lamp ignition is catered for by a glowbottle starter-switch which is housed within the extended metal collar above the lamp cap.
This particular lamp was offered in two versions, this being the Ozone-free design which is intended for applications where only the UVC radiation is desired. Its principle use was in the erasure of EEPROM style memory chips, and for various photochemical applications. Larger lamps were generally employed in water sterilisation equipment, although technically this small version is also suitable.
The more common alternative employs a quartz tube with a broader transmission window which allows the passage of ozone-producing wavelengths below 200nm. The presence of ozone is highly effective at destroying odours and the latter lamp was employed in particular in equipment for the disinfection and sterilisation of air, often incorporated in air conditioning units.
Both versions have been largely superseded today by Germicidal UV lamps based on the compact fluorescent format, which offer higher energy densities and a more compact lamp than this old screwbase type with integral starter. Where even more power is required, a standard linear germicidal tube is the preferred alternative.