Flow meters are devices which enable, at any given time, the accurate red-out of the flow rate of the streaming medium in a unit of time – the current flow rate. For fluids (liquids and gases) the units for quantity may be given as mass (kg, t) or volumetric units (l, m3) — that is why it is also important to distinguish between mass flow rate and volumetric flow rate. The bridging element between the two flow rates is the density of the measured medium (ρ).
In general, flow rate is measured:
- By measuring the temporally-defined difference in volume of the two liquids (fluids)
- By measuring the streaming velocity through a known cross-section, according to the following equation:
Q = v x A
Q – flow rate of the fluid; e.g.: m3/h
v – streaming velocity of the fluid at known cross-section; e.g.: m/s
A – area of the known cross-section; e.g.: mm2
- Indirectly by measuring the pressure difference (Bernoulli)
Irrespective of the procedure by which the flow rate is determined, the correct choice — when it comes to choosing a suitable meter — should be driven by: the right technology and the appropriate size.
In this process, you should consider:
Properties of the meter; measuring requirements, measuring range, accuracy, steplessly variable or sample measuring, allowed losses, existing infrastructure...
Properties of the medium; purity, chemical properties, temperature, pressure, presence of particles, air...
Manner of installation and maintenance; spatial limitations, power supply, communication, inspection requirements, access, human resources, and means of maintenance...
Economic factors; operating and maintenance costs, return on investment...
In our range of offer you will find standard magneto-inductive and ultrasonic flow meters for potable water, process water, and waste water, as well as many flow-metering solutions for aggressive media, gases, air and steam.