Measuring Gas Velocity with the D-FL 100 Differential Pressure Bar

D−FL 100 Seite 5To prevent residue accumulation on the differential pressure bar, the gas should be clean. Ductscontaining high-particulate gases should be periodically purged with compressed air. By moving thelever in front of the differential pressure bar, each chamber can be purged separately (Fig. 4).Fig. 4:Possible settings of the switching valveCalculating the volume of gas flow also depends on the density of the gas (Eq. 1). To obtain an accuratecalculation, the contents of the gas and their molecular weights must be known (DIN 1952). No gaswatermixtures can be measured, because of condensates.Because it is directly affected by gas density fluctuations, velocity must be measured under operatingconditions. If a calculation for standard conditions is required, the D-FL 100-10 Display will take thestatic pressure and temperature into account. The gas density always depends more on temperaturethan on pressure, so the correction for absolute pressure can be neglected in most cases. Temperatureand pressure can be measured using additional sensors, and the results transferred to the D-FL 100-10Display.GmbH