The Use of Photoelectric Cells for Measuring the Static Duration of Combustion in Cigarettes/Anwendung von Photoleitern zur Bestimmung der statischen Branddauer von Cigaretten

The semi-automatic assembly presented here (photoelectric cells used to measure the static duration of combustion in cigarettes) resembles in principle the design published by Wiley and Holmes. Essentially it consists of an electrical start-stop device timed by 2 signals activated by the movement of the glowing zone through a thermo-transductor field. It differs from the earlier design in that, instead of a hot bi-metallic thermocoupling, it uses a photo-transistor very selective in IR (maximum response 1.55 mµ, with a 50 % drop for 0.8 and none for 2 mµ). The device also has a mechanical system for holding the cigarette and positioning the phototransistors, and an electrical cigarette lighting system. The apparatus is set up for simultaneous control of 5 cigarettes.