The first thing that is evident when searching for differential pressure transmitters is that there is an astounding number of options on the market. Often it is easy to become bogged down in the specifics of each particular design when it is really a big picture overview that is the most effective first step.
The Role of the Transmitter
All pressure is basically defined as the force applied to an area. With the need for differential pressure measurements what is needed is the difference in pressure, the force on the area, at two different points. There is no standard that the change in pressure is compared to such as the atmospheric pressure or a vacuum. Instead, the difference is the pressure change between the two points.
The use of differential pressure transmitters is essential in maintaining system flow, stability and control. These transmitters will measure specific changes in pressure between the two points that is they relayed, in the form of an electronic signal, to the system. This can allow control to maintain the desired pressure differential or ensure there is no difference in pressure between the two points.
The Importance of Design
While it may seem evident, the use of differential pressure transmitters will often be dependent on the specifics of the system. All of the different transmitters have a primary element, which can be a venturi, orifice plate, tube or a flow nozzle. This actually measures the increase in the flow as the flow at one point increases compared to the flow at the other.
The secondary element will be used to measure the change in the differential pressure related to the flow. It will use the data from the primary element, which will be recorded independently of the temperature of the liquid, semi-solid or gas, ambient temperature or the actual fluid pressure.