Chesterton’s 1210 Ceramic Stationary Seal Face may be used with 891 and 440 rotary seals to form a dual mechanical seal.  The 891 is the inboard seal exposed to the process fluid.  The 440 is the secondary (outboard) seal that seals barrier fluid to the atmosphere. 

• Can supply variable barrier pressure through the unit.
• Shields the environment from the pumped fluid.
• Provides a clean fluid to the inboard seal faces.
• Can operate as a pre-installed "stand-by" seal in the event of primary seal maintenance.