What is the primary characteristic of a positive displacement pump?

A positive displacement pump is characterized by its method of moving fluid through the system by trapping a fixed amount of liquid and forcing it into the discharge pipe. This action is achieved through mechanisms that create repeating cycles of push and pull, which allows for consistent and controlled delivery of the fluid.

By utilizing chambers or pistons, positive displacement pumps effectively take in a specific volume of fluid and then discharge it with each cycle, creating a predictable flow rate regardless of the pressure conditions in the system. This characteristic makes these pumps particularly suitable for applications requiring precise fluid control.

In contrast, other options such as continuous flow without pulsation or low wear rates may not accurately reflect the nature of positive displacement pumps, as these types of pumps can exhibit pulsation and wear depending on the design and materials used. Therefore, the defining feature of the push and pull action through repeated cycles is what differentiates a positive displacement pump from other types of pumps, confirming its primary characteristic.