Which filter is described as a coarse filter used to prevent large solids from entering the pump?

• A. Return line filter (low pass)
• B. Suction line (Mesh)
• C. Pressure line filter (high pass)
• D. Off-line filtration

Answer: (B)

In a hydraulic system, protecting the pump from debris is essential because large solids can cause wear, clogging, or cavitation. A coarse filter placed in the suction line, such as a mesh screen, serves as the first barrier by catching big particles before they are drawn into the pump. Placing it on the suction side makes sense because the pump draws fluid directly from the reservoir, so filtering at this point prevents solids from entering the pump in the first place. The mesh is intentionally coarse to avoid overly restricting flow while still stopping large contaminants.

The other options don’t fit this protective role as neatly. A return-line filter sits in the path when oil returns to the reservoir, typically handling contaminants after the pump rather than preventing them from getting in. A pressure-line filter is on the discharge side, protecting components downstream from fines, not preventing solids from entering the pump. Off-line filtration is a separate servicing or conditioning setup, not part of the normal in-line protection of the pump.