The drawing below illustrates the operating principle of a diaphragm seal assembly. A pressure measurementinstrument such as a conventional pressure gauge or electronic pressure transmitter is either mounted directly
to the diaphragm seal or attached to the seal by means of a capillary or cooling element.
A diaphragm within the diaphragm seal separates the gauge / transmitter from the process medium. Any part of the
diaphragm seal (i.e., diaphragm, lower housing, gaskets) which will be exposed to the process medium is selected
from materials resistant to pressure, temperature and possible chemical attack by the process medium.
The diaphragm seal is also filled with a transmitting fluid or system fill fluid. Any pressure applied by the process
medium to the seal diaphragm is hydraulically transmitted to the pressure element of the gauge / switch / transmitter
thus generating a pressure reading.