Differential particulate mass monitor with intrinsic correction for volatilization losses

摘要

The mass of particulate matter in a particle laden gas stream (42) is measured using a first mass detector (50A) and a second mass detector (50B). Switching means (48A, 48B, 56) causes the particle laden gas stream and a substantially identical but particle-free gas stream to alternately engage the first mass detector and the second mass detector respectively during successive measurement time periods. A difference between a reading provided by the first mass detector (50A) and a reading provided by the second mass detector (50B) for each of the successive measurement time periods is determined. This difference intrinsically corrects for volatilization losses occurring during the measurement time periods. A measure of the mass or concentration of particulate matter in the particulate laden gas stream is determined from this difference. Single detector embodiments (10', 40') are also presented.