Pressure sensors
A pressure sensor can basically be classified in the category of pressure measuring devices. They represent the first link in the measuring chain during pressure measurement and convert the physical variable of pressure into an electrical output signal. Pressure sensors are suitable for measuring stationary pressure, pressure differences, pressure fluctuations or even sound pressure.
Different types of pressure sensors
Depending on the measurement method, there are three common types of pressure sensors: absolute pressure sensors, differential pressure sensors and relative pressure sensors.
Absolute pressure sensors
In general, this type of pressure sensor refers to vacuum pressure measurement with a pressure of almost 0 bar.
Differential pressure sensors
This type of pressure sensor measures the pressure difference between two measuring chambers in which two different pressures prevail.
Relative pressure sensors
This method or type of pressure sensor is similar to that of the differential pressure sensor. The relative pressure to the atmosphere serves as the basic reference here.
Pressure sensors at B+B
B+B offers two different types of pressure sensors: ceramic pressure sensors and stainless steel pressure sensors. These sensors can be used to measure either absolute or relative pressure. The pressure measurement range can also be selected individually for each variant.
Stainless steel pressure sensors
The stainless steel thick-film measuring membranes offer high safety in the event of pressure peaks as well as above-average media resistance. They are also vacuum-resistant (negative pressure-resistant). These properties make the sensors ideal for measuring and monitoring rapidly changing pressure processes. They have a ratiometric voltage output in the range of 1.5 to 3.5 mV/V. The monolithic stainless steel pressure sensors are available as standard for relative pressure ranges up to 100 bar.
Ceramic pressure sensors
The ceramic pressure sensors are characterised by their excellent resistance to aggressive and corrosive media.
Furthermore, the pressure sensors are precisely temperature-compensated and have high long-term stability and burst pressure resistance. Various pressure sensor variants cover a pressure range from 1 to 400 bar and can be used in a temperature range from -40 °C to 135 °C. The output signal is a pressure-dependent differential voltage that can be converted into a standard output signal of, for example, 0...10 V or 4...20 mA by means of simple signal amplification. The appropriate evaluation electronics are available from B+B under item number DS-MOD-10V or DS-MOD-20MA.
There are stainless steel and ceramic measuring cells for relative and absolute pressure measurement types, whereby the measuring range can be selected individually.
The measuring medium only comes into contact with stainless steel (1.4404 stainless steel), which provides excellent resistance to aggressive and corrosive media.
Relative pressure measures pressure in relation to the current ambient air pressure and is often used in applications where fluctuations in atmospheric pressure play a role. Absolute pressure, on the other hand, refers to a perfect vacuum as a reference point and measures the total pressure regardless of the ambient pressure. This type of measurement is particularly useful in applications where the actual pressure must be determined without external influences. While relative pressure sensors measure the pressure difference to the environment, absolute pressure sensors measure the total pressure relative to absolute zero.