Screw conveyors are used in the process industry for transfer of thick slurries, powders and granular media. these conveyors are often designed and fabricated for specific applications whereby their typical operating conditions involve volumetric transfer rather than pressure buildup. The screws drive shafts are normally sealed by packing rings which are seldom leak tight. When leakage of media is not acceptable, Type 240 seal with its dedicated compression unit may offer the needed solution.