Patent ID: 8375766
Filing Date: 2013-02-19
Classification: G01N

Abstract:
1. A method of monitoring particles flowing in a stack, comprising: (1) monitoring a signal resulting from electrical interaction of the particles with an electrical-interaction monitor having a first calibration; (2) calculating from the monitored electrical-interaction signal, according to the first calibration, a value for a parameter relating to the particle flow; (3) monitoring a signal resulting from detection of light scattered from the particles; (4) comparing the electrical-interaction signal with the scattered-light signal to obtain a relative magnitude of the signals; (5) identifying a change in the relative magnitude of the signals; (6) altering the calibration of the electrical-interaction monitor in response to the change; and (7) calculating from the monitored electrical-interaction signal, according to the altered calibration, an altered value for the parameter relating to the particle flow, in which the signals are compared by calculating the ratio of the electrical-interaction signal to the scattered-light signal, and changes in that ratio identified.