Flow meter: How to choose the right flow meter
A flow meter must suit the specific application. Before choosing a flow meter, you should establish the medium, flow type, output, pressure, temperature, pipe size and mounting method. Asking the right questions makes it easier to find a flow meter that provides consistent measurements and meets the requirements of your operation, process and installation.
What application will your flow meter be used in?
Flow measurement is important in many industrial applications — from heating and cooling systems to food production and life sciences. Stricter safety procedures, process optimisation and requirements for quality and environmental impact mean that accurate flow measurement is often an essential part of operations.
The choice of flow meter therefore depends not only on the measuring point itself, but on the entire application. A flow meter must be able to operate reliably under the specific operating conditions and provide the measurement data the process requires.
Choose a flow meter based on the medium and its properties
The first question is which medium your flow meter will be measuring. Requirements differ depending on whether you are dealing with liquids, gases or compressed air, and no single flow meter technology can measure all media with the same output and the same low level of uncertainty.
The properties of the medium also matter. Among other things, you should establish whether the medium has high or low viscosity, whether it is conductive or non-conductive, and whether it is aggressive or non-aggressive. The wetted parts of the flow meter must be compatible with the specific medium to ensure consistent and reliable measurement.
Does your flow meter need to measure volumetric flow or mass flow?
A flow meter determines the flow of a medium through, for example, a pipe installation. Some flow meters are designed to measure velocity, others measure volume, while others measure mass flow. The right choice depends on what you need to control, monitor or document in the application.
A general distinction is made between volumetric flow and mass flow. Volumetric flow is often measured in l/s, l/h or m³/h, while mass flow is measured in kg/h or t/h. You should therefore establish what output the process requires before choosing a flow meter.
Calibration and installation affect your flow meter
All flow measurement involves a degree of uncertainty. Choosing the right flow meter is therefore not enough; the meter must also be maintained correctly. Regular calibration is important if the flow meter is to continue measuring accurately over time.
Installation conditions also have a significant impact. Among other things, you should establish the pipe size, the distance to bends, and whether the flow meter can be fitted directly into the pipework or a clamp-on solution is required. The IP rating and ATEX approval can also be crucial in certain environments.
Questions to answer before choosing a flow meter:
- Which medium will the flow meter be measuring?
- Is it a liquid, gas or compressed air?
- Does the medium have high or low viscosity?
- Is the medium conductive or non-conductive?
- Is the medium aggressive or non-aggressive?
- Does the flow meter need to measure volumetric flow or mass flow?
- What output should the flow meter have: analogue, digital, pulse, frequency or alarm?
- Do you need a local or remote display?
- What are the minimum and maximum flow rates?
- What are the pressure and temperature in the application?
- What pipe size will the flow meter be installed in?
- How close are bends, valves or other sources of disturbance to the measurement point?
- Will the flow meter be installed directly in the pipeline or as a clamp-on unit?
- What IP rating does the flow meter need?
- Does the flow meter need to be ATEX-approved?
Choosing a flow meter?
Hans Buch can help you clarify your requirements for the medium, flow type, output, pressure, temperature, installation and calibration.
Find the right flow meter
If you already know your requirements, you can find flow meters in our online shop or contact us for technical advice.
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