Indirect Mass Flowmeters

Venturi-type thermal mass flowmeter. (Courtesy of TSI Inc.) 

Mass flowmeter combining a magnetic flowmeter and a radiation-type densitometer in a single unit. 

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Any combination of flowmeter and suitable specific gravity (density) meter (Section 6.6) can in theory be employed to produce a mass rate of flow. However, these so-called indirect meters have a limited range and accuracy and require careful and frequent calibration and maintenance. An instrument based on the turbine flowmeter (Volume 1, Section 6.3.9) and acoustic density meter (Section 6.6.1) has been employed with good results<8) (see Fig. 6.5). 

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