Misure di pressione


The principle of level measurement with a pressure transmitter is based on the use of hydrostatic pressure to determine the level of a fluid in a container.
The pressure transmitter is positioned at the bottom of the container and measures the pressure exerted by the fluid above it.
Since pressure depends directly on the depth of the fluid, it is possible to calculate the fluid level using a direct relationship between pressure and depth.
This principle is based on the fundamental law of fluid statics, which states that the pressure in an equilibrium fluid increases linearly with depth.


The difference between absolute pressure and relative pressure is that absolute pressure takes into account the total atmospheric pressure, while relative pressure only considers the additional pressure compared to the local atmospheric pressure.
Absolute Pressure: Absolute pressure is the pressure measured compared to the total vacuum, i.e. compared to the pressure value of an environment completely free of gas or fluids. In other words, absolute pressure takes into account the existing atmospheric pressure. This means that absolute pressure includes both atmospheric pressure and the pressure due to the fluid or gas being tested. A common example of an absolute pressure measurement is the barometer, which provides absolute atmospheric pressure.
Relative Pressure: Relative pressure, on the other hand, is the difference between the measured pressure and the local atmospheric pressure. This type of measurement only considers the additional pressure compared to the atmospheric pressure present in the surrounding environment. In essence, gauge pressure provides a rating of pressure relative to a local reference point.
For example, when you measure the tire pressure of an automobile, you are measuring the pressure relative to the surrounding atmospheric pressure.