Basics of Permanent Pressure loss in Differential Pressure Flow Meters

The standard primary flow sensors commonly used in differential pressure flow meters are the orifice plates, flow nozzles and venturi tubes. These flow meters are often called "head loss" meters because there is a permanent pressure loss downstream these meters. In other words, upstream pressure never recovers to its original value downstream these meters. Various designs of these flow sensors are available which can provide the optimal meter for the desired operating conditions and requirements of the user. A critical factor in choosing a differential pressure flow meter is the pressure loss of the flow sensor. As a rule, when applying differential pressure devices, pressure loss must be small. This is because pressure loss means energy loss and higher pumping/compression costs.

The different installation versions of the primary flow sensors (orifice plates, flow nozzles, venturis) of differential pressure flow meters commonly used in flow measurement are tabulated below:

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