Issues with the main seal fluid film in tandem mechanical seals – seeking advice
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In the 52 system and the 53A system, is the liquid film between the rotating and stationary rings of the primary seal with series sealing made up of medium or white oil? If it is medium, then why is the pressure of white oil higher in the 53A system – shouldn’t the liquid film be white oil then?
Seeking answers online; discussions from everyone are also welcome. Thank you, everyone
52 Sealed tank, no pressure applied； 53 Pressurize the sealed tank ；
The medium with the higher pressure is the one that forms the liquid film
Then why does a dirty medium easily damage the mechanical seal? Logically, since it’s a liquid film and the oil medium is dirty, it shouldn’t have much of an impact, right?
Whether it is 52 or 53, it is primarily designed for auxiliary sealing (the second layer of seal). If the medium is dirty, first, the compensation mechanism may fail; secondly, debris may get into the sealing surface, which leads to leakage in the mechanical seal.
The sealing medium between the friction pairs on the end faces is determined by the pressure in the sealing chamber; in case of scheme 52, where the primary sealing pressure is higher than the secondary sealing pressure, the medium used for primary sealing should be that particular medium. In 53A, the lubricating oil pressure is higher than the medium pressure, and the main sealing medium is the medium in the isolation tank.