The change in the inductance is evaluated with an inductive sensor.
It consists of 1 housing with 2 chambers. A copper beryllium membrane is in the center to which a small ferrite plate is attached.
Example of an inductive measuring cell from FSM AG
On the external sides of the chambers, two coils are arranged opposite each other, between which the ferrite plate can move. Its movement caused by pressurization changes the inductance of the coils in opposite directions, which can be acquired very accurately. Inductive sensors are suitable for particularly low pressures in the measuring range up to 0 to 0.1 mbar = 0 to 10 Pa. The application areas are limited to non-aggressive or inert gases as they occur in heating, ventilation, or clean room technology.
JUMO. Pressure and differential pressure transmitter 404304