Question 35 OSE02 - Assistant Engineer - OSV

The Correct Answer is C ### 1. Explanation for Option C (Wire-mesh filter element) **Wire-mesh filter elements** are typically designed to be washable and reusable. These elements rely on impinging large and medium-sized dust particles onto a coarse wire screen or mesh, which may or may not be coated in oil (in the case of oil-bath filters or permanent industrial filters). Because the filtration mechanism is structural and not reliant on fine, irreversible media (like paper or synthetic fibers), the element can withstand repeated cycles of cleaning. Maintenance involves removing the element, washing it thoroughly with a solvent or detergent, drying it, and sometimes reapplying a fresh coat of oil to enhance dust capture before being reinstalled in the intake housing. ### 2. Explanation for Incorrect Options **A) Panel-type filter element:** Panel filters, which commonly use pleated paper, cotton, or synthetic media, are highly effective at trapping fine dust particles. However, the debris becomes deeply embedded within the microscopic structure of the media. Attempting to clean (wash or blow out) these elements usually damages the media, compromises the filter’s efficiency, or causes accumulated dirt to be pushed through the pores, leading to immediate engine wear. Therefore, panel-type elements are almost universally designed for **periodic replacement**. **B) Spiral-rotor filter element:** This terminology usually refers to a type of *pre-cleaner* (a centrifugal filter or cyclonic separator), such as a Turbo II pre-cleaner. These devices use vanes or rotors to spin the air, forcing large particulates outward where they are ejected or dumped before reaching the main filter element. The element itself (the rotor/vane assembly) is a piece of hardware that constantly self-cleans by shedding dirt, rather than being a filtration media element that must be periodically removed, washed, and reinstalled. **D) Multi-tube filter element:** Similar to spiral-rotor systems, multi-tube filters (also known as cyclone filters) are high-efficiency pre-cleaners. They use an array of small, stationary cyclone tubes to separate particulates from the airflow. The debris is collected in a hopper and often automatically or manually dumped. Like the spiral-rotor system, this is system hardware designed to separate dirt, not a media element designed for manual washing and reuse.