Gas Flow Measurements and Controls
DOI link for Gas Flow Measurements and Controls
Gas Flow Measurements and Controls book
The knowledge of gas throughput or mass flow rate is vital in vacuum technology because of the design of a vacuum system, the determination of conductance of vacuum components, pumping speed, and control of technological processes and their efficiency. Gases are admitted into vacuum in a controlled way. Devices for the measurement of gas flow rates are called flowmeters, which can measure the gas amount flowing into a system per unit time by volumetric methods, in which the gas volume entering a vacuum system per second is measured at known pressure and temperature. Alternatively, the measurement can be carried out by gravimetric methods, in which the gas mass entering a vacuum system is weighted. Gas flow rate can be determined by gas accumulation or diminishing methods in metering systems. Gas flow rate can be determined using a calibrated conductance of an aperture and measuring the pressure difference across the aperture.