How To Choose The Right Flow Meter?

Jon Lawson

Test and measurement professionals use flow meters for a wide variety of applications which demand accuracy. Precisely for this reason, it is important to choose the right type of flow meter and carry out regular calibration from calibration experts to ensure that it delivers accurate results. Here Edward Simpson from RS Calibration considers some guidelines. 

Cost and popularity 

These two are tricky factors to consider. You should keep in mind that if you have cost as your priority and look for a good bargain, you might compromise its quality – physically and in terms of performance. If such a device needs frequent and costly maintenance, the amount you saved while buying it, will mean nothing. Also, when it comes to popularity, choosing the most preferred option can lead to a disaster as it may not meet your requirements. Cost and popularity both are important but weightage should be given in correlation to the type of application for which you need the flow meter. 

Mass or volume?

A flow meter is either a mass flow meter or a volumetric flow meter. However, you can calculate mass from volume and vice versa if you know the density and the variables agreed upon. Depending on the nature of application, objective of measurement and the components, you will be able to decide whether a mass flow meter or a volumetric flow meter works best for you. 


Different types of flow meters are available. It is important that you understand your requirements thoroughly before purchasing. Keep in mind the property of the fluid to be measured. This will help you narrow down on the type of device you need. 


Know the properties of the fluid being measured properly before buying a flow meter to measure the flow rate of that fluid. Some of the properties you need to have a clear idea about are as follows: 

•    Type 
•    Density
•    Viscosity
•    Temperature
•    Pressure
•    Condition and Contaminants
•    Flow Consistency
•    Flow Range
•    Corrosive Nature

It is also important to know the physical dynamics of the application site where the fluid will be measured. These include: 

•    Configuration of the pipe before and after the flow meter
•    Length of straight pipe at the inlet and outlet of the flow meter
•    Size of the pipe
•    Material of the pipe
•    Angle of the pipe
•    Surrounding Environment


Ask the supplier about the failure rate of the flow meter in terms of the type of application you need it for. Calculate the longevity and the total life cost. Ensure that the instrument you are choosing has a long life. 


Understand where exactly and how the flow meter needs to be installed before choosing it. This is important as it can substantially affect the accuracy and efficiency. Can it be affected by any obstructions in the pipeline such as bends, joints or valves which may cause disturbances in the flow of the fluid to be measured? These parameters will help you make an informed decision. 


Other parameters 

You should also consider these specifications before choosing a flow meter:

Accuracy. It is one of the most obvious and crucial parameter to look for while selecting a flow meter. Inaccurate results can cost your business a lot more than just profits. Hence, be sure of the instrument’s accuracy before selecting it. 

Repeatability. This parameter is more crucial than accuracy because accuracy requires repeatability, but repeatability doesn’t require accuracy. It only requires consistency. 

Rangeability or Turndown Ratio – choose a flow meter which offers the largest range of fluid measurement without compromising on other components. 

Hygiene Requirements – flow meters used in industries such as pharmaceuticals or food require strict sterile environments. Hence, keep in mind the type of hygiene requirements required for the flow meter to operate based on the nature of its application. 

Budget. This is also an important aspect which should not be compromised on. Hence, choose a flow meter which meets all the other specifications and fits within your budget. 

If the measurements are over or under, valuable material can be lost and the profits of your business can be negatively impacted. Hence, follow the above listed useful tips to choose the right flow meter for your business application. 


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