Patent ID: 7772855

Claim:
An instrument for measuring the concentration of particulates in a fluid, including: particulate collecting means for collecting the particulates in the fluid; temperature measuring means for measuring the temperature of the particulate collecting means; flow rate measuring means for measuring a flow rate of the fluid passing through the particulate collecting means; impedance measuring means for measuring the impedance of the particulate collecting means; and information processing means, wherein the information processing means includes: time measuring means for measuring the elapse of time; constant determining means for determining an impedance change per unit time-particulate concentration constant from the measured temperature and the measured flow rate; impedance change per unit time computing means for computing a change of the measured impedance per unit time measured by the time measuring means; and particulate concentration determining means for determining the concentration of the particulates from the change of the impedance per unit time computed by the impedance change per unit time computing means by use of the impedance change per unit time-particulate concentration constant determined by the constant determining means.