Which test is specifically done to determine the presence of bottom sediment and water in lube oil?

The correct choice identifies the centrifuge spin test as specifically aimed at determining the presence of bottom sediment and water in lube oil. This test operates by using centrifugal force to separate the liquid mixture based on density differences. When lube oil containing sediment and water is spun in a centrifuge, the denser materials (sediment and water) are forced to the bottom, allowing for clear observation of their presence in the oil.

This method is essential in assessing the quality of lube oil since the presence of water and sediment can indicate potential contamination or degradation, which can significantly affect the performance of machinery. The centrifuge spin test provides a quantitative measure that helps maintenance personnel and engineers evaluate oil health and decide on the appropriate actions, such as filtration or oil change.

In contrast, the other tests mentioned do not specifically target the identification of both bottom sediment and water in lube oil as a primary outcome. The transparency test measures how clear the oil is but does not analyze sediment or water. The visible sediment test is focused on the observation of particulates but lacks the quantitative capabilities and efficiency of the centrifuge method. The purifier efficiency test evaluates how well purification systems are functioning, not the direct contamination levels in the oil itself.