This diaphragm seals come between the pressure measuring instrument and some medias which can damage the instrument or be harmful if they get directly in touch with the instrument. In many industrial processes, it happens a lot that the media cannot or should not get into direct contact with the instrument. Sometimes that is for the sake of keeping the instrument work properly as the media is too viscous and might easily clog the process connections. And sometimes it is for hygienic purposes.
The flexible metal diaphragm of seals is made of SS316L by default and the space between this flexible diaphragm and the instrument process connection is filled with a filling fluid, chosen in best interest of where the instrument is going to be installed.
So the intended pressure is transmitted via the flexible diaphragm to the filling fluid and then via the filling fluid to the pressure instrument.
This diaphragm seals are vacuum protected and also not sensitive to sudden sharp increase in pressure.
This threaded diaphragm seal can be used for corrosive and hot media and also poisonous fluid which is dangerous for environments. and very much suitable for high pressure measurement at high temperatures. At 400C process temperature,