Among the following equipment, which one is not typically described as a “wet classifier” used for liquid–solid classification?

Introduction / Context:
Liquid–solid classification separates particles based on settling behavior in fluids. Common wet classifiers include rake classifiers, spiral classifiers, hydrocyclones, and elutriators. Some high-speed centrifuges are primarily for phase separation rather than granular classification.

Given Data / Assumptions:

• Devices listed include a high-speed centrifuge and hydro-mechanical classifiers.
• We distinguish devices meant for classification of particles in slurry from those mainly used for liquid–liquid separation or polishing.

Concept / Approach:
Hydrocyclones and rake classifiers are canonical wet classifiers. An elutriator uses upward flow to classify by size/settling rate. A Sharples (Sharples) supercentrifuge is primarily for liquid–liquid separation (e.g., cream separation) or very fine polishing, not the typical granular size classification duty performed by rake/hydrocyclone units.

Step-by-Step Solution:

Verification / Alternative check:
Process flowsheets show hydrocyclones/rake classifiers between grinding stages, whereas supercentrifuges appear in dairy, biotech, or fine polishing contexts.

Why Other Options Are Wrong:

Common Pitfalls:
Equating any centrifuge with a classifier; overlooking the typical duty of each device.

Final Answer:
Sharples (Sharples) supercentrifuge