Top entry mixers and bottom entry agitators on sealed tanks will have a mechanical seal of some sort. For many sanitary process vessels, the mixer must have some type of sealing barrier to provide either a dust tight vapor seal, a pressure tight seal to allow pressure and or vacuum in the mixtank, or an aseptic sealing device to provide a hygienic seal between the tank id and the outside of the vessel. There are a variety for mixer use, including single dry running double assemblies with a liquid or gas flush, and a variety of other lip seals and packing materials which can be used. Starting with the least expensive sealing mechanism for a rotating mixer or reactor, we have a simple dust cover assembly, and elastomer lips sealed, a spring-loaded CIP mixer seal, a packing seal, a USP class VI lip seal, a single dry running mixer seal, a single with an aseptic debris well, and then we have higher pressure double, custom steam sterilizable and split options.