Electro-Pneumatic Level Transmitters (EPLT)
General description of the product
Electro-pneumatic level transmitters (EPLT), usually consisting of:
- a pneumatic unit, supplied by an external source of compressed air (instrument air quality – Class III piping system, P<16 bar, T<200°C), incorporating filtering device(s), non-return valve(s), a safety valve, an air pressure regulator, and a connection to a sounding/bubbling pipe (immersed in tank from tank top and terminating with an open end close to the bottom);
- an air pressure sensing device;
- an electric transmitter.
The pressure sensing device and the electric transmitter, together, can be identified as a “pressure transducer”.
The level measurement is obtained indirectly, through measurement of the air backpressure needed for bubbling of air through the liquid content of the tank: such pressure is in direct proportion with the height and the specific gravity of the liquid above the sounding pipe lower termination, plus (in case of inerted tanks) the pressure of the inert gas itself.