MDE 11 Q7

• Correct Answer: C) Oil is spun at high speed to separate contaminants based on density

Explanation: The centrifugal filter operates by spinning the oil at high speed within the rotor. This high-speed rotation creates a centrifugal force that causes the denser particles (contaminants) to move outward, separating them from the less dense, cleaner oil. This process is entirely mechanical and relies on the principle of density differences.

Correct Answer: D) The oil’s contamination level

Explanation: The contamination level of the oil directly affects how often the purifier needs to discharge. High contamination levels will require more frequent discharges to ensure the oil remains clean.

• Correct Answer: B) They are collected on the inner wall of the rotating bowl

Explanation: The contaminants are separated from the oil by the centrifugal force generated by the rotating bowl. As the oil spins, the denser contaminants are forced outward and collect on the inner wall of the bowl, where they remain until the filter is cleaned or serviced. The cleaner oil is then returned to the engine.

Correct Answer: C) A leaking cylinder head gasket

Explanation: A leaking cylinder head gasket can allow coolant or water to mix with the engine oil, leading to contamination.

• Correct Answer: C) To remove contaminants from the oil by using centrifugal force

Explanation: The primary function of a centrifugal type lubricating oil filter is to remove contaminants such as dirt, metal particles, and other impurities from the lubricating oil. It does this by spinning the oil at high speeds in a rotating bowl or rotor, which generates centrifugal force. This force pushes the denser contaminants to the outer wall of the rotor, separating them from the cleaner oil.

Correct Answer: C) By using a series of filter media that cause small water droplets to merge into larger droplets, which are then easily separated.

Explanation:
Coalescer filters use specialized filter media designed to coalesce, or combine, small water droplets in the fuel into larger droplets. Once the water droplets are large enough, they can be separated from the fuel more easily, typically settling out and being removed via a water separator.

Correct Answer: C) Incomplete separation of contaminants

Explanation: Incomplete separation can lead to oil carryover, where the oil mixed with contaminants exits the separator, causing oil losses.

Correct Answer: B) Viscometer test
Explanation: A viscometer test is used to measure the oil's viscosity, which is crucial for ensuring proper lubrication and engine performance.

These questions cover various aspects of assessing the condition of lubricating oil in a large medium-speed diesel engine on board a vessel.