Recommended where fluid is highly corrosive, contaminated, viscous or liable to crystallize inside measuring system. The gauge above the diaphragm seal is filled with silicon oil that transmits the pressure acting on the diaphragm to bourdon tube Diaphragm is welded to the upper part of sealed unit and therefore it is possible to seperate the upper and lower parts to clean the diaphragm without removing the gauge. Diaphragm can be ANSI 316. Tantalum, Hastelloy C and Monel. Pressure gauge can be of type 1, 3 and 5 and process connection with Standard threads or flanged connection confirming to ANSI, BS or DIN Specifications.