In a centrifugal pump with a volute design, which statement accurately describes the diffuser function?

In a centrifugal pump with a volute design, which statement accurately describes the diffuser function?

• A. It requires a separate diffuser ring
• B. The diffuser is not used in volute designs
• C. The diffuser is provided by an external housing
• D. In a volute design, the discharge chamber acts as a diffuser

Answer: (D)

In a centrifugal pump, the diffuser’s job is to convert the fluid’s velocity head into pressure head. In a volute design, that diffusion happens right in the discharge chamber—the volute itself. The spiral, expanding shape of the volute slows the fluid and spreads it out as it leaves the impeller, turning kinetic energy into static pressure. There’s no separate diffuser ring in this design, and diffusion isn’t provided by an external component; the volute housing is the diffuser.

That’s why the statement stating that the discharge chamber acts as a diffuser is the best description.