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Principles of Ionization Smoke Detection. Development of a New Sensor for Combustion-generated Submicrometer Particulates.
NTIS: PB 271 920 :21 pages
A new prototype ionization-attachment fire detector was developed by the Bureau of Mines for detecting combustion-generated submicrometer particulates. It is much more sensitive than the conventional ionization smoke detector, and it has the following added features: 1. A primary charging current of unipolar air ions is generated by a gold-coated, radioactive center electrode of a cylindrical diode. 2. Submicrometer particulates are flowed axially through the unipolar cloud where they acquire charge. The charged particles impinge upon a third electrode, located downstream, resulting in a current which is directly proportional to the particulate concentration. 3. Additional electrodes analyze the particulates in terms of their mobility and thus determine their size distribution. 4. A filter and cyclone assembly protects the ionization chamber against ambient dust. An analysis of conventional ionization smoke detector performance is also presented in terms of source strength, chamber geometry, and applied potential.
IH; Report of Investigations
NTIS Accession No.
NTIS: PB 271 920
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division