How to Calculate Your Pump's Flow Rate


It's important that you know the flow rate of your system. Flow rate is how much fluid you can transport within a given time. Knowing this helps you achieve two critical things:

  1. You can assess if an existing system isn't working efficiently. If you know the flow rate you should be achieving and yet your system is not performing, then you can take the necessary action.
  2. You can determine the exact set-up you will need to transport, at the volume you require. 

Calculating Flow Rate During Planning Stages

Determining the flow rate you will need is an essential part of planning your system design, before you go ahead and order or install your new pump. If you get this wrong, then you might have to invest money in replacement equipment which could seriously impact your budget.

The equipment most suited to your specific needs will be reliant on three things:

  • The type of fluid you need to pump
  • The distance it has to travel from point A to point B
  • The volume of fluid which needs to be transported in a given time to make the system economical

All of these considerations will be specific to your project. The volume of fluid you wish to transport over a given time will be your flow rate, while the type of material and the distance between input and output will affect the flow rate you can realistically achieve. Therefore, these three aspects of a healthy system are all interlinked.

If possible, the best way to ensure that you order the correct equipment is to contact an expert who can then suggest the equipment you should buy. 

Assessing Flow Rate in a Functioning System

Let's say, for example, that you need to move 200 litres of a fluid every 20 minutes. That means your equipment, have to be able to produce a flow rate of 20 litres per minute, or 3.33 litres per second. 

Once your system is installed and you have chosen the correct pump for the job, you will need to assess the system's performance. There are a number of factors you could measure, but right now we will stick with flow rate. To measure the flow rate of your system you can:

  1. Use a Flow Meter: This is a simple device which can measure the amount of fluid passing through it. Attach this to your discharge pipe, as close as possible to your pump and it should give you a reliable reading of your flow rate.
  2. Collect Fluid: If the fluid you are transporting is safe to use in this way, you can collect the fluid in a measuring vat or bucket (if the system is small enough, care must be taken). If you know how much the container holds, then you can measure the amount of time it takes to be filled. This will give you an accurate flow rate. 

If the flow rate is not what it should be, given the expected performance of your installed pump, then you can move on and begin to assess each piece of your system for flaws. You may be interested in this blog: How Friction Impacts Head Pressure

Or, It could be that your pump is simply in need of replacement. If so, Global Pumps has a range of excellent industrial pumps available for any circumstance.


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Tags: Troubleshooting


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