How Important is Accurate Flow Measurement?

Whether your operation needs to pump out wastewater or pump in clean water, maintaining an accurate flow rate is vital. Too high of a flow rate can cause pump leaks and various problems. Not enough flow can cripple your productivity. You must have accurate control of the pumps and efficient ways to measure and monitor the flow at all times.
Measuring Flow Rate
Depending on your operation and pump application, flow rate can be measured in gallons per minute (GPM), cubic feet per second (CFS) or cubic meters per second (CMS) or other units of fluid measurement. Whichever units your system uses, the the pump and pump system must be configured to achieve your desired flow rate and metered during operation to verify that desired flow rates are consistently achieved.
Most operators will prefer a scientific approach, using math to achieve flow continuity. The continuity equation is simple:
Flow = Velocity x Area
Flow Measurement Methods
Flow should be measured at various points along the pipeline running into and out of the pump. The ideal result is that the flow rate is constant no matter where you measure. There are numerous methods you can use to measure the flow and assure continuity:

  • The Old Eyeball Method – A really experienced operator might be able to “eyeball” the flow and see that it is consistent. Eyeballing may work for processes with little concern for accuracy or risk of loss, but most operations will want a more scientific approach.


  • Manning Equation – This is an empirical formula that measures various factors such as velocity, depth, channel friction and slope. Although the Manning Equation can be more complicated than the eyeball method, it is also significantly more accurate.


  • Metering Equipment – This is the most efficient and effective way to measure flow rates and flow consistency. There are various meters that can be installed like a transit time meter, Venturi meter, primary device, area-velocity meter, magnetic flow meter and turbine flow meters. All will provide accurate measurements to help you monitor flow rates and keep the pump system running at optimal efficiency.

Get the Right Equipment with Cortech
However, you choose to monitor and maintain constant flow, it’s clearly an important objective to make sure your pumps are doing what you need them to do at all times. For help in selecting and configuring the right pumps for any application, as well as specialized metering equipment to help you monitor things like flow rates, contact Cortech today. Our engineering experts can guide you to make the right equipment decisions.