Pressure transmitters are used for converting the low-level electrical outputs of pressure sensing devices into high-level signals that are used in process control applications. Pressure transmitters utilise different types of sensing technologies and can measure accurate pressure of a gas or liquid. Mechanical deflection device like Bourdon tubes, diaphragms or bellows consist of a flexible element that is mechanically deflected with the variations in pressure.
Differential pressure transmitters are generally used for measuring the pressure difference between two points in a system. They are commonly found in filtration applications. Moreover, a differential pressure sensor can also be used for monitoring the cleanliness of a filter in either a gas or liquid application.
Differential pressure transmitters in filtration applications:
The upstream pressure (commonly known as influent pressure or line pressure) drives the medium through the filter. Also, a line is installed just before the filter and connected to the high side of the sensor. The contaminants from the medium are then removed using a filter. Next, the effluent pressure or downstream pressure, leads the material through the system with smaller amount of contaminants than before.
If the filter is free from contaminants, it will measure 0 PSI differential pressure. As the filter becomes blocked, the pressure on downstream reduces, thus creating a great difference between the low and high sides. A differential pressure sensor unit will always offer a linear output signal depending on the differential pressure.
Applications of differential pressure transmitters include water filtration for commercial and residential works, flow measurements and transmissions
