A process connection for two measurement ranges

This customized solution was developed to meet a specific customer requirement in the pharmaceutical industry: level measurement in a tank. The application requires very high measurement accuracy, even under significantly varying pressures and a wide temperature range at a single measurement point. The solution employs two pressure transducers with different measurement ranges, both mounted on a pressure separator. Depending on the stage of the process and the level in the tank, this system can switch from a higher measurement range up to 4 bar to a lower measurement range down to 400 mbar, while maintaining the highest measurement accuracy in each case. The lower measurement range is also overload-protected, and the sensor is insensitive to higher pressures. To achieve high measurement accuracy despite temperature fluctuations, the pressure transmitter was additionally designed with our patented LTC diaphragm. The LTC diaphragm (LTC = Low Temperature Coefficient) compensates for
temperature-induced volume expansion of the filling fluid using a specially shaped stainless steel diaphragm and increases measurement accuracy by up to 70 percent.