How to Calculate the Flow Rate of your Pump?

Pumps are an integral part of almost all industries now. From construction and mining to automotive and aerospace, pumps play a vital role in keeping these industries moving forward. While there are many essential parameters in pumps, one critical parameter is the pump flow rate which becomes a first important factor for pump manufacturers.

What is the Pump Flow Rate?

Pump flow rate simply refers to the volume of fluid that is moving through a pump in a given time period. There are various units through which it is measured, and they include cubic meter/hour (m3/h), litre/sec (l/s) or gallons per minute (GPM). Different pump manufacturers refer to different pump flow units.

Why should I calculate the flow rate?

Flow rate is the amount of fluid that the pump can transport within a given time. Knowing the flow rate of your pump can help you achieve two key things:

● You can figure out if your system is working efficiently. If you know the expected flow rate and the current flow rate, then you can identify if your system is underperforming. This helps you make the right action to improve the pump’s performance.

● You can figure out the right setup needed to transport the liquid/fluid at the desired volume.

WHAT ARE THE FACTORS AFFECTING PUMP FLOW RATE?

The flow rate of a pump can be affected by several factors, including the size and type of pump, the speed at which it is operating, and the resistance of the system it is pumping into.

● Pump Size: Larger pumps can move more liquid than smaller pumps. This is why it’s essential to choose an appropriately sized pump for your application.

● Pump Speed: This is the number of times the pump can complete an entire cycle in a minute and is measured in rotations per minute (rpm). The faster the pump speed, the higher the flow rate.

● Liquid Viscosity: Viscous liquids (such as honey) will flow more slowly than non-viscous liquids (such as water). This is because it takes more energy to move a viscous liquid.

● Liquid Density: Heavier liquids (such as oil) will flow more slowly than lighter liquids (such as water). This is because it takes more energy to move a heavier liquid.

● Pipe Bends: The fewer the number of bends in the pipe, the higher the flow rate. This is because there is less resistance to flow when there are fewer bends in the pipe.

● Pipe Size: The larger the pipe diameter, the higher the flow rate. This is because there is less resistance to flow when there is a larger diameter pipe.

● Pipe Length: The shorter the length of the pipe, the higher the flow rate. This is because there is less resistance to flow when there is a shorter length of pipe.

Now that you know the basics of pump flow rate, you can begin to select a pump that is appropriate for your application. Keep in mind that the factors listed above will all affect pump flow rate, so it’s essential to consider each one when you give your requirements to the pump manufacturers.

How to Calculate the Flow Rate of your Pump?

To calculate the flow rate of a pump, you will need to know the following information:

● The speed of the pump

● The size of the pump’s impeller

● The density of the fluid being pumped

With this information, you can use the following formula to calculate the flow rate:

Flow Rate = Pump Speed x Impeller Size x Fluid Density

Pump speed is measured in revolutions per minute (rpm). To convert from rpm to hertz, divide by 60. For example, if a pump operates at 1000 rpm, its frequency would be 16.67 Hz.

Impeller size is typically given in inches. For example, a standard impeller size is 6 inches.

Fluid density is typically given in pounds per cubic foot (lb/ft3). For example, water has a density of 62.4 lb/ft3.

Let’s say you have a pump that is operating at 1000 rpm, has an impeller size of 6 inches, and is pumping water with a density of 62.4 lb/ft3. So the flow rate would be:

Flow Rate = 1000 rpm x 6 inches x 62.4 lb/ft3

Flow Rate = 37,440 lb/ft3 per minute

To convert from pounds per minute to gallons per minute, divide by 8.34. Therefore, the flow rate in this example would be:

Flow Rate = 37,440 lb/ft3 per minute / 8.34

Flow Rate = 4,488 gallons per minute

To convert from gallons per minute to metre cube per hour, you need to multiple by 0.2271. Therefore the final flow rate in this example would be:

Flow Rate = 4,488 gallons per minute x 0.2271

Flow Rate = 1,019.22 metre cube per hour

The good news is that there are many online flow rate calculators available for free, which you can consider using if you do want to get into too much mathematics.

You need to calculate three factors before ordering the right pumps:

● The type of fluid you need to pump – is it viscous or clear? What’s the temperature of the pumped fluid? Etc.

● The distance the fluid has to travel

● The volume of fluid that needs to be transported in a specific time

All these three factors will vary based on your industrial needs. The volume of fluid that you want to transport determines the flow rate of the pump. The type of fluid and the distance transported both play a huge role in impacting the flow rate that you can achieve. Hence, all these three factors play a crucial role in determining the size and type of pump needed. We highly recommend that you contact a pump sizing expert to help you decide the correct equipment to buy. We offer free pump sizing guidance for all our clients, to help them find the best pumps for their requirements.