PHOTOELECTRIC SMOKE DETECTOR

摘要

In a system for checking whether a smoke detector is functioning a test member 54 which may have a small light transmitting area is moved into a region V which is illuminated by a light source system 38 and viewed by a detector system to the test member (54) can be temporarily positioned in the light beam so that one side of said member is exposed to the light and the other side is in the view of the photo-responsive device. The test member is usually biased by a spring 58 Fig. 4, to be out of the region V unless an associated operating member 56 is depressed. Various types of test member are disclosed (Figs. 6-11 not shown).