Describe : Separation Seal (Contacting Technology) The Type 83 is a contacting carbon bushing designed to isolate the bearing oil from the dry gas seal cartridge. Normally supplied as a complete seal cartridge, unique inner and outer segments are specifically designed to prevent oil migration and minimise wear. Nitrogen is normally injected between the two segmented bushings effectively creating a pressure barrier between the bearing and DGS cavity. Advanced materials and design ensure minimal wear and promote long life. Unlike many contacting separation seals the Type 83 is designed to operate on cryogenically dry nitrogen.