What is a characteristic of non-positive displacement pumps?

Non-positive displacement pumps are designed to move fluid by creating a flow that is not fixed and can change depending on the system pressure and other factors. This characteristic allows them to vary the flow rate according to the demand of the system, which is particularly beneficial in applications requiring flexibility. For example, as the backpressure in the system changes, these pumps can adjust their output accordingly, which contrasts with positive displacement pumps that deliver a constant flow rate regardless of outlet pressure.

The ability to achieve variable flow rates makes non-positive displacement pumps suitable for a wide range of applications where adaptability is crucial. This includes processes like chemical mixing, circulation systems, and many others where fluid dynamics may fluctuate based on operational needs.

By focusing on the definition and functioning of non-positive displacement pumps, we can see why the option regarding variable flow is accurate and highlights a fundamental nature of these pumps in engineering applications.