Which type of pump is characterized as a Variable Displacement pump?

A Variable Displacement pump adjusts the volume of fluid being moved based on the needs of the system, allowing for more efficient operation under varying conditions. Among the options provided, a Positive Displacement pump is the type that can exhibit variable displacement characteristics.

Positive Displacement pumps work by trapping a fixed amount of fluid and forcing it out upon every cycle. This could be done through various mechanisms, including reciprocating or rotary motions. When designed for variable displacement, these pumps can adjust the volume they displace during each cycle, optimizing flow rates based on demand, which is critical in applications where precise flow control is necessary.

Reciprocating pumps are a type of Positive Displacement pump that use a piston to move fluid and can also be designed for variable displacement. However, they are specifically characterized by their back-and-forth motion.

Centrifugal pumps operate based on rotational kinetic energy and do not inherently allow for displacement variation in the same manner as Positive Displacement systems. They provide a continuous flow rather than a fixed-volumetric discharge per cycle, making their operation less adaptable to changes in system demand.

Rotary pumps, also a subset of Positive Displacement pumps, move fluid by the rotation of a mechanism, but without the ability to adjust displacement