Found mainly in industrial process systems, differential pressure gauges are designed to measure pressure difference between two pressure points. According to WIKA Worldwide, a differential pressure gauge has two inlets connected to the points being monitored. In effect, it performs the mathematical operation of subtraction through mechanical means. As such, it eliminates the need for a control system or an operator to determine the reading differences.
Just like any other mechanical tool, differential pressure gauges can fail from time to time. According to Omega, water condensation and pipe vibration are the leading causes of failure. This is because in colder climates, these two issues can freeze and cause damage to the gauge housing. WIKA Worldwide identifies chemical plants, refineries and petrochemical plants as typical settings where differential pressure gauges are used. They are largely used for filter monitoring, liquid level monitoring and flow monitoring.
There are two general categories of pressure gauges: traditional and filled. Omega states that the pivots, links and pinions of a traditional pressure gauge are highly sensitive to vibration and condensation, while the filled gauge has a relatively longer lifespan because it is has fewer moving parts and because it has a housing filled with viscous oil. This oil dampens pointer vibration and also leaves no room for humid air to penetrate.