What type of pump has only one impeller?

The single-stage pump is defined by its use of just one impeller to move fluid. This configuration allows for efficient operation when the required pressure rise is not excessively high, making it ideal for applications that do not demand multiple stages of fluid pressurization.

Single-stage pumps are characterized by their simplicity and ease of maintenance, as they have fewer components compared to multi-stage or two-stage pumps. This type of pump is commonly used in scenarios where the flow rate is critical but the total head (or pressure) does not require the complex design of pumps with multiple impellers.

In contrast, two-stage pumps employ two impellers to achieve higher pressure and flow rates, making them suitable for applications requiring greater energy transfer. Centrifugal pumps can either be single-stage or multi-stage depending on the design, but simply being a centrifugal pump does not imply it has only one impeller. Multi-stage pumps contain multiple impellers within the same unit to achieve a significant increase in pressure, making them appropriate for high-pressure systems where single-stage pumps would be insufficient.