MEASURING THE DENSITY, VELOCITY AND MASS FLOW OF GASES

摘要

A meter and a method of measuring the velocity of gas in a duct are described, and gas density and mass flow may also be measured. In one form the meter has an ion source and two ion collectors, so that gas in the duct is first ionized and then passes the collectors. The source and the collectors are devised to present little or no impedance to gas flow. A voltage pulse is applied to the first collector and the interval between this pulse and the resulting effect in the number of ions collected at the second collector is measured to give gas velocity. Density measurement is by determining the number of ions collected between pulses at the second collector, and mass flow is obtained by forming the product of velocity and density.