Carbon particulate monitor with preseparator

Abstract

Carbon particulate concentration of diesel exhaust or other sampled gas is measured by collecting the particulate on a high efficiency filter while measuring the amount of sampled gas passing through the filter. The filtered particulate is then heated in an oxygen rich environment to oxidize carbon within the particulate to carbon dioxide. The amount of resulting carbon dioxide is measured with a closed measurement loop to derive a corresponding measurement of the amount of filtered particulate. Particulate concentration is calculated by comparing the amount of carbon particulate with the measured amount of sampled gas passed through the filter. Filtered particulate can be heated incrementally to obtain a measurement of volatile carbon components within the particulate prior to the oxidation of the non-volatile carbon component. The filter employed to collect the carbon particulate is of a high temperature resistant type making it reusable and can be either integral with or inserted into the oxidation chamber of the instrument. Oxidation of the particulate inherently concurrently cleans the filter for reuse. An upstream preseparator can extend the life of the high efficiency filter. Particulate can also be collected for analysis by using an accelerating impaction nozzle in conjunction with a heatable impaction plate.