Mud Hoppers, Dies and Inserts MUD HOPPERS National Oilwell offers two sizes of Mission mud mixing hopper / jet pump combinations 3" and 6" to efficiently emulsify drilling fluids including polymers.  This design incorporates a jet nozzle with a venturi to cause a vacuum action at the bottom of the mud hopper. This vacuum efficiently draws the dry mud into solution under pressure induced by the venturi.  Effective flow rates are from  200- 1000 GPM. DIES & INSERTS The Mission product line provides the largest offering of Dies and Inserts in the Industry.  Manufactured from high quality, high alloy extruded steel, our dies and inserts consistently deliver superior performance.  We utilize computer controlled manufacturing equip- ment, and techniques for consistent fits, and lower product costs. Dies and Inserts. 100 Mission Mud Mixing Hopper.