Improvements to optical smoke detection equipment

摘要

The main problem with light scattering optical smoke detectors is to achieve a high sensitivity and discrimination, keeping stray light from the light source from affecting the photoelectric detector in the absence of smoke particles, whilst achieving a high light-collecting efficiency when smoke particles are present. This invention uses a laser or other highly collimated light source 6 to direct a beam through a tube 1 with the light- guiding properties of transparent solids such as glass or plastics, so that the light collecting efficiency can approach 100%. The tube channels the scattered light to a light detector 3. It is particularly adaptable to aspirated fire detection systems.