Flow measurement is the generic term for the measurement of a volume flow per unit of time. The most common unit of measurement is cubic meters per second (m³/s), but other units are also common.
In practice, devices according to DIN 1319 are used for flow measurement. Depending on the application, they are of different design and follow different measuring principles. Among others, these devices are frequently found in industrial applications:
- Swash plate meter: Uses water flowing into a chamber to cause the wobble plate to move. The total number of swings in a given period of time indicates the flow rate.
- Electromagnetic flow meter: Uses a magnetic field that creates a voltage in the medium through positive and negative charge carriers. The voltage is used to infer the flow rate via the flow velocity.
- Ultrasonic flowmeter: Uses an acoustic signal. The time it takes for the wave to travel through the medium indicates the current flow rate.
- Impeller meter: Uses an impeller that generates a signal proportional to the flow rate.
- Mass meter: Uses an electrical heating wire and two temperature sensors. The minimum heating of the volume flow by the heating wire is sensed by the temperature sensors and the flow rate is inferred from the temperature difference at the two different points.
- Differential pressure flow meter: Use the pressure drop at a deliberately constricted point to infer flow rate via Bernoulli’s equation.
What should be considered when selecting a flow meter?
The properties of the medium being measured are critical to the proper selection of the device. Density, temperature, pressure, conductivity and viscosity should be considered.
Where are flow measurements performed?
Flow measurements of liquid and gaseous media are performed in many areas. Examples would be:
- Water and waste water
- Chemistry and petrochemistry
- Oil and gas
- Power and steam generation
- Pulp and paper
- Food and beverage
Flow measurement is also a performance component in on-site visualization
hydrothermal processes in process water circuits of industrial temperature control systems. Basically, flow measurement always also provides information about the efficiency and performance of a fluid power system. With a data logger, the flow can be measured at two different points and tracked over a longer period of time.« Zurück zum Glossar Index