PRELIM-Q1

A ship's fuel purifier is not effectively separating water from fuel. Based on your understanding of centrifugal separation, what is the MOST LIKELY cause of this issue?

• The fuel temperature is too low, increasing viscosity.

• The purifier bowl is rotating too fast.

• The fuel density is lower than that of water.

• The purifier is using a clarifier disc stack.

During operation, an engineer notices an increase in water content in the purified fuel. Which component should be checked first to analyze the root cause?

• Discharge valve

• Disc stack

• Bowl speed regulator

• Motor bearings

If a ship's purifier is producing fuel mixed with solid contaminants, which of the following would be the most effective corrective action?

• Increase the purifier’s rotational speed.

• Inspect and clean the disc stack.

• Reduce the fuel flow rate.

• Add a water separator before the purifier.

A vessel's engine is showing signs of fuel contamination. How should the engineer determine whether the purifier is functioning correctly?

• Check the temperature of the incoming fuel.

• Measure the discharge pressure of the purified fuel.

• Analyze the fuel sample from both inlet and outlet.

• Increase the purifier’s operating speed.

A purifier operates based on the principle of centrifugal force. If the rotational speed decreases, what will MOST LIKELY happen to the separation efficiency?

• It will improve because the fuel has more time to settle.

• It will remain the same as long as the density difference is maintained.

• It will decrease as the centrifugal force weakens.

• It will only be affected if the water content increases.

Which of the following BEST explains why purifiers use a disc stack inside the bowl?

• To slow down the fuel flow for better separation.

• To increase the surface area for improved phase separation.

• To collect solid particles at the center of the bowl.

• To mix water and fuel before separation occurs.

If a ship’s purifier is designed to separate three phases, which of the following is NOT a correct discharge location?

• Water discharged through a dedicated water outlet

• Clean fuel collected at the center of the bowl

• Solids collected in a sludge tank

• Fuel and water mixed in a common discharge line

A new engineer is troubleshooting a purifier that fails to start. After verifying power supply and motor function, what should be analyzed next?

• The fuel viscosity

• The purifier bowl assembly

• The ship’s fuel quality

• The exhaust system

If an operator mistakenly installs a clarifier disc instead of a purifier disc, what operational problem is MOST LIKELY to occur?

• The purifier will not start due to an imbalance.

• Water will not be separated effectively from the fuel.

• The motor will overheat due to excessive speed.

• Solids will accumulate too quickly in the discharge valve.

Why is it important to maintain the correct rotational speed in a ship’s fuel purifier?

• To prevent water from emulsifying with fuel

• To allow heavier solids to move toward the center

• To ensure that lighter fuel moves outward

• To increase fuel viscosity for better separation