What does a stage in rotating equipment typically consist of?

• A. Two impellers working in combination
• B. One impeller and an associated diffuser or volute
• C. A single baseplate and mounting plate
• D. The assembly of multiple components in a series

Answer: (B)

A stage in rotating equipment, particularly in the context of pumps or compressors, typically consists of one impeller along with a corresponding diffuser or volute. The impeller is the rotating component that imparts energy to the fluid, while the diffuser or volute is responsible for converting the kinetic energy imparted by the impeller into pressure energy, allowing the fluid to be efficiently transported through the system.

This configuration is fundamental in the design of centrifugal pumps and compressors where the stage is the basic building block of the entire machine. By understanding that the impeller works in conjunction with a diffuser or volute, one can appreciate how these components work together to achieve the desired flow and pressure characteristics of the rotating equipment.

The other options do not accurately describe what constitutes a stage. For instance, having two impellers working in combination might suggest a multi-stage configuration but does not reflect the standard definition for a single stage. A single baseplate and mounting plate pertain more to the structural support of the machinery rather than the flow delineation of stages. The assembly of multiple components in a series might suggest a broader system setup but does not focus specifically on what defines a stage in rotating equipment.