RLOD#50 (2020.09.24) 1987 Philips SOX-E 66W

The inner frame structure of old low-pressure sodium lamp had a particular intricate design, especially in larger lamps where the fragile discharge tube is larger, heavier and has a greater potential difference across its electrodes during operation. These characteristics imposed some strict constraints and requirements on the frame design, which had to be robust yet flexible and had to provide a proper galvanic insulation so as to prevent seal failure by sodium electrolysis. As the cost of manual labor was not yet an issue in the early days of the SOX(-E) technology, the burner frame made at Philips for its 66 to 135 W lamps consisted of a complex assembly of bent wires and steatite tube sections, all crafted by hand. This structure also holds a pair of dispenser rings for the barium mirror getters that are flashed onto the bulb neck so as to maintain a high vacuum inside the lamp.