January 4, 2024

Pressure and flow rate in spray nozzles

Ikeuchi spray nozzles

What is the relationship between flow rate and pressure in spray nozzles?


Increasing the flow rate of a spray nozzle can help to improve the cleaning efficiency, increase the coverage of a spraying area, or help to achieve the desired coating or thickness. The relationship between flow rate and pressure in spray nozzles is directly connected. As the  pressure increases, the flow rate also increases.


What is a flow rate?

The flow rate refers to the amount of water or fluid that moves through the spray nozzle.

What is pressure?

Pressure refers to the amount of force exerted on an external object or fluid. In a spray nozzle, pressure refers to the pressure needed to force the water through the piping system and spray nozzle.

How can you increase the flow rate?

Increasing the flow rate in a hydraulic spray nozzle a lot more difficult than in a pneumatic spray nozzle. This is because the hydraulic spray nozzle only uses liquid pressure. If you want to double the flow rate in a hydraulic spray nozzle, you have to increase the liquid pressure by as much as 4 times. This might not even be possible depending on the type of nozzle. With a pneumatic spray nozzle however, you can double the flow rate by simply adjusting the pressure. In order to do this, you will need to know  how much liquid and air is being distributed at what pressure. You can find out by using a flow rate diagram.

What is a flow rate diagram?

From a flow rate diagram you can read the spray flow rate and the spray pressure as well as the air consumption and pressure.  You can also see the mean droplet diameter. The spray flow rate is on the horizontal axis and the air consumption is on the vertical axis. The blue and red lines indicate the liquid and air pressure, respectively. The red lines show the compressed air pressure and the blue lines show the water pressure. The liquid pressure is at the end of the red of blue lines from 0.1 MPa to 0.5 MPa.

Watch the video below to fully understand how to read a flow rate diagram:



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