Sealing systems	Tank pressure
1/  Hydraulic sealing: Hydraulic sealing is the most economic solution to prevent the introduction of liquid elements from outside of the tank. Variant (hydraulic guard): the deflector can be doubled and filled with water to seal an atmospheric or a radioactive sealing.	Atmospheric pressure (a few mBar)
2/  Lip seal: Lip seal prohibities tank interio/exterior exchanges. Easilyer replacement.
3/  Gland packing: System with compressed braids allowing sealing.	Average pressure
4/  Simple mechanical seal (dry, lubricated or gas): The most advanced technical solution for tanks under pressure and with a high temperature of service. Principle: 2 grains rub one against the other.	High pressure
5/  Double mechanical seal (dry, lubricated or gas): Same principle as the simple rechannical seal with increased safety, when grain is weared, by the presence of the second pair of grains.
6/  Magnetic coupling: Solution allowing a total seal, the best adapted to dangerous products.