K-Tron's Bulks Solids Pump (BSP) Feeder model 150 uses positive displacement action to feed free-flowing bulk materials. The BSP 150 employs at least one vertical rotating spool to create feeding ducts. Incoming material is captured in the duct and rotated to discharge. While in the duct, the material locks up and moves in plug flow, moving material from storage hopper to discharge outlet. The feeder uses four feeding ducts to reach feed rates of 1.6 to 160 ft3/hr. Both gravimetric and volumetric models are available and the unit can be incorporated into K-Tron's K4G continuous gravimetric blender.