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What is Differential Pressure?

What is Differential Pressure? Differential pressure is essentially the difference in pressure between two given points.

It is a type of pressure measured within different industries using differential pressure sensors.  

There are 3 common types of pressure;

·         Differential Pressure

·         Gauge Pressure

·         Absolute pressure  

Gauge pressure refers to the difference between a measured point and the atmosphere. Absolute pressure is the combined pressure of the atmosphere and the measured point. Differential pressure is more complex than Gauge or Absolute pressure as it has two variables.

What are differential Pressure switches?

Differential pressure switches are mechanical devices used for sensing the difference between two measured points.

Differential pressure switches have two ports which are connected to the two pressure sources. When connected to the pressure sources, the differential pressure switch will monitor the difference in the pressure between them, when the pressure reaches a set point the switch will either make or break a circuit as the internal diaphragm deflects under pressure making contact – either SPST or SPDT. This will trigger an alarm to alert the user that the pressure has changed. The set point in a pressure switch can be either pre-set or field adjustable depending on the application.

What are differential pressure switches used for?

Differential pressure switches are often used in applications for an energy saving way to determine when a device isn’t working as it should. This also helps with planned maintenance and safety critical applications.

Some examples of these types of applications are;

·         Determining the respiratory flow in medical devices

·         Air proving

·         Clogged filter detection in extractor fans

·         Exhaust ducts

·         Flue gas

·         Air conditioners

·         Air flow blockages in various devices

·         Gas pressure

·         Fans

Pressure sensors from Variohm

All of our pressure sensors and switches can be found on thePressure Sensors section of our website. For more information contact us; +44(0)1327 351004 or

For more information please contact: Variohm EuroSensors Ltd Email: Tel:+44 (0) 1327 351004 Fax: +44 (0) 1327 353564

Article date:

Variohm EuroSensor
Author: Variohm EuroSensor