Rotary Positive Displacement Pumps, N.E.S.

Peristaltic pumps use a rotating mechanism to compress a flexible tube and propel fluid, and they are generally considered a form of rotary positive displacement pump. However, classification can depend on the specific design and whether a more precise heading applies. Importers should verify with a licensed customs broker, particularly for pharmaceutical or food-grade peristaltic pump imports.

Screw pumps use one or more helical rotors to move fluid axially with minimal pulsation, making them preferred for high-viscosity fluids and sensitive applications such as crude oil transfer, polymer processing, and marine fuel systems. Their low-shear, smooth-flow characteristics distinguish them from gear or vane pumps in the same heading, and this application specificity is often relevant when assessing end-use certificates or trade-remedy scope.