Centrifugal Pump Characteristics Analysis

The question asks to identify the statement that is not correct regarding centrifugal pumps.

Analysis of Options:

• Statement 1: They can not be used for pumping water containing sediments (silt, sand etc).

  This statement is incorrect. While standard centrifugal pumps may be damaged by abrasive materials, specialized designs (e.g., using harder materials, specific impeller types like vortex impellers) exist to handle fluids with suspended solids. Therefore, it's not universally true that they *cannot* be used.

• Statement 2: They are quite durable and safe against high pressure.

  This statement is generally correct. Centrifugal pumps are known for their robust construction and can operate reliably under various pressure conditions, depending on their design specifications.

• Statement 3: They can be installed in limited space.

  This statement is generally correct. Centrifugal pumps often have a compact design compared to other pump types, making them suitable for installations where space is limited.

• Statement 4: Such pumps require priming.

  This statement is generally correct. Most common centrifugal pumps are not self-priming and require the casing and impeller to be filled with liquid before startup to create the necessary suction. Self-priming designs are available but not the default for all types.

Conclusion:

The statement that is not correct in the context of centrifugal pumps is that they absolutely cannot be used for pumping water containing sediments.