We currently offer two diaphragms that come with a parylene surface treatment, Silicone Plus and EPDM Plus.
is a material that mechanically bonds itself to the base
elastomer. It is not a coating, it is a surface treatment that is applied by vapor deposition and therefore does not peel or flake off with wear.
Parylene is similar to PTFE in that it has very good
chemical resistance. Because we have to use
a very thin application of Parylene, the chemical
resistance of the diaphragm is enhanced, but it is not quite as good as Teflon.
Probably the best
feature of Parylene is the improved slipperiness of the Silicone and EPDM surfaces. This improved slickness of the material means that the surface is more hydrophobic. In addition, you can easily removed the diaphragm from the valve during maintenance.
We find that the Paralene treatment greatly enhances the performance of the base elastomer. In our experience, the Paralene treatment typically doubles the life of the diaphragm.