Almost all classic flow measurement solutions such as positive displacement meters and turbine meters use volumetric methods. This is to say that the output of these technologies is measured in volumetric units such as LPM and GPM. Unfortunately, a series of flow measurement applications require the output to be measured in mass units. Some of these applications are custody transfer, emissions monitoring and chemical mixing or batching. When volumetric flowmeters are used in such applications, their output has to be converted into mass units. This conversion requires the multiplication of the readings by a media density value. Liquids change their density with the variation of their temperature. Gas media change their density with both temperature and pressure. This uncontrollable density variation leads to a very low accuracy of such systems that use volumetric meters. By using mass flowmeters, this problem is eliminated, as these devices provide direct mass flow readings which aren’t influenced by temperature and pressure variations.
Thanks to the ability of mass flowmeters to provide accurate readings, work efficiency and product quality are very much improved. Many times, these flow measurements are the perfect tools for obtaining information on the global process performance. This is possible due to the law of conservation of mass. This law states that the mass that enters a system should always be equal to the mass leaving it within a specific interval of time. This is why all global plant operations rely massively on mass flow meters rather than anything else.
There are two categories of flow meters. The first category includes exclusively volumetric flow meters such as Magnetic, Ultrasonic, Positive Displacement and Turbine meters. When these devices are combined with the measurement of temperature and pressure and with a mass flow calculator, they become indirect mass flow meters. They require several types of sensors to be able to provide these measurements. As there are situations in which direct mass flow measurement isn’t possible due to various issues, indirect mass flow measurement can be quite satisfactory. Nonetheless, it’s worth noticing that SmartMeasurement offers direct mass flow solutions that work in all conditions.
Direct Mass flow measurement are Coriolis and thermal flowmeters such as SmartMeasurementTM’s Coriolis flowmeter family of ALCM meters with various flow tube construction to best fit any application used mainly for liquids. While in gas measurement SmartmeasurementTM’s, ATMF family of thermal mass flow with direct mass flow and temperature outputs are the smart solution for any gas applications.
In steam measurement, the only technology able to measure mass flow is a self-compensated vortex flow metes. The ALVT family of vortex flow meter produced by SmartMeasurement can take direct mass flow readings on steam flow with built-in temperature and pressure sensors well as mass flow transmitter. These flow meters are perfect for steam flow measurement because when steam temperature and/or pressure changes the output is the actual mass flow of the steam. Non compensated vortex meters or other volumetric flow meters will not measure the true mass flow of steam when steam temperature and/or pressure changes.