Single and double slurry cartridge seals
Double cartridge seals are an advanced design and are used where the process/pumped fluid is not a suitable lubricant for the sealing faces.
This is used with aggressive pumped media or when atmospheric leakage of pump fluid is unacceptable.
Double Cartridge seals use barrier or buffer fluid as required by the application or specified API plan.
This requires a support system to manage the barrier/buffer fluid.
https://nexus-eng.com/seal-support/