Thermal mass flow meters Coriolis

There are many other types of flow meters that can be used such as venturi meters, vortex shedder flow meters, and Coriolis flow meters. Any of these may be preferred depending on the application. Fluid flow can also be measured indirectly using chemical analysis and mass and energy balance calculations. Air flow measurements are commonly made this way since an oxygen analyzer is generally more accurate than a thermal mass flow meter. 

Some flow calorimeters (continuous calorimeters) make use of air as a heat transfer medium in other cases, gases or liquids react with each other or are products of the reaction. In the latter case, a possible approach to the measurement of amounts of substances consists in allowing the newly formed phase (usually a gas) to leave the system via a flow meter. Here the flow rate provides a measure of the quantity of substance transformed per unit time. Usually a pressure difference is the measurand as in capillary flow meters or is caused by the back pressure of the measuring instrument however, the possibility of pressure rises (caused by a buildup ) in the vessel must be taken into account. Other techniques for measuring amounts of gas make use of displacement gas meters, turbine meters, or ultrasonic meters. In these cases, the volume flow is the measured quantity. For measuring the mass flow, Coriolis or thermal mass flow meters can be used. In any case, it is very difficult to reduce the uncertainty of flow measurements below approximately 1%. This can only be achieved in exceptional cases when great effort is made to calibrate the meter with fluids of similar and known thermophysical properties (e.g., heat capacity, thermal conductivity, viscosity, density, etc.). 

Coriolis flow meter Hot-wire anemometer Thermal mass flow meter Piezo-electric element Magnetic transducer... 

Velocity meters measure the velocity v of fluid flow in a pipe of known cross section, thus yielding a signal linearly proportional to the volume flow rate Q. Mass meters provide signals directly proportional to the mass flow rate m = pQ, where p is the mass density. Coriolis meters, which are true mass meters, can be used only for liquids. Thermal-type flow meters use a heating element and determine the rate of heat transfer, which is proportional to the mass flow rate. This type of device is used mostly for gas measurements, but liquid flow designs are also available. 

Thermal mass flow sensors have also found wide application for pure media, such as metering of N2, compressed air, or oils because of their compact design, precise detection, and lower cost than comparable Coriolis meters. Their handicap is the... 

Mass Meters Mass flowmeters measure the rate of mass flow through a conduit. Examples include Coriolis flowmeters and thermal mass flowmeters. Coriolis flowmeters can measure fluid density simultaneously with mass flow rate. This permits calculation of volumetric flow rate as well. Section 8 includes brief descriptions of Coriolis and thermal mass flowmeters. 

Full-bore meters include variable-head meters such as venturi and orifice meters and variable-area meters such as rotameters. These will be described in some detail. Briefer descriptions are given of other full-bore measuring devices V-element, magnetic, vortex shedding, turbine and positive-displacement meters, ultrasonic meters, and mass flow devices such as Coriolis and thermal flowmeters. 

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