The purpose of the diaphragm seal is to protect expensive instruments. Its job is to transfer the pressure of the process medium through the membrane seal to the filling fluid and then transmit the resulting pressure wave to a pressure gauge or sensor at the head of the measuring assembly. Choose a suitable diaphragm seal filling liquid. The characteristics of the diaphragm seal fill fluid determine the performance of the sealing system to a large extent. Both in response time and temperature dissipation conditions. The initial consideration in choosing a sealed diaphragm to fill fluid is the media compatibility of the process. The temperature and pressure of the process medium are also important factors because all the filling fluid expands or contracts with changes in temperature. Remember that there is a direct relationship between the measured response time of the viscosity and the density of the filling fluid. More viscous filling fluids lead to longer response times. In addition, the filling fluid with a higher density can have an impact on the mounting. Types of filling fluid: glycerin, silicone oil, and halogenated carbon are the most commonly used sealing diaphragm filling fluids. Extended reading: Flat Pressure Sensor for High Viscosity Fluids