Which characteristic best describes a positive displacement pump?

A positive displacement pump operates by drawing a fixed volume of fluid into a chamber and then displacing it through a discharge valve. One of its most defining characteristics is that it provides a relatively constant flow rate, regardless of variations in pressure within the system. This behavior is primarily due to the mechanism of how these pumps are designed; they displace a specific volume with each cycle, leading to consistent flow characteristics under a given speed of operation.

As the pressure in the system increases, the flow produced by a positive displacement pump experiences only a minor change. This means that even if the system pressure increases, the pump continues to move approximately the same amount of fluid, which distinguishes it from other types of pumps, like centrifugal pumps, where flow can decrease significantly as pressure increases.

This characteristic makes positive displacement pumps extremely reliable in applications that require a steady flow of liquid, even when the pressure fluctuates, which is essential for maintaining efficiency and performance in hydraulic systems.