Primary flow element
Encyclopedia
A primary flow element is the element
of a flow meter that serves to indicate the quantity
or velocity
of flow.
For example, in the case of an orifice flow meter, the differential pressure across the orifice plate is the primary flow element. A turbine meter is equipped with a magnetic pickup that senses the proximity of the turbine blades as the fluid motion causes the turbine to spin; this pickup is the primary flow element for a turbine meter. Diaphragm meters and other positive displacement meters are equipped with a crank shaft, the rotation of which acts as the primary flow element.
Electrical element
Electrical elements are conceptual abstractions representing idealized electrical components, such as resistors, capacitors, and inductors, used in the analysis of electrical networks...
of a flow meter that serves to indicate the quantity
Quantity
Quantity is a property that can exist as a magnitude or multitude. Quantities can be compared in terms of "more" or "less" or "equal", or by assigning a numerical value in terms of a unit of measurement. Quantity is among the basic classes of things along with quality, substance, change, and relation...
or velocity
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
of flow.
For example, in the case of an orifice flow meter, the differential pressure across the orifice plate is the primary flow element. A turbine meter is equipped with a magnetic pickup that senses the proximity of the turbine blades as the fluid motion causes the turbine to spin; this pickup is the primary flow element for a turbine meter. Diaphragm meters and other positive displacement meters are equipped with a crank shaft, the rotation of which acts as the primary flow element.