Which lubrication system is used for the crankcase on a reciprocal compressor?

• A. Crank Case Lubrication
• B. Cylinder/Packing Lubrication
• C. Piston Lubrication
• D. Valve Lubrication

Answer: (A)

The thing being tested is which lubrication path protects the moving parts inside the crankcase itself. In a reciprocating compressor, the crankcase houses the crankshaft and its bearings (and sometimes the gear train). The crank case lubrication system keeps oil in the crankcase and supplies it to these components, providing a lubricating film to reduce wear, carry away heat, and prevent seizure. This is the lubrication setup specifically for the crankcase region.

The other options refer to lubrication for different parts: cylinder/piston lubrication serves the piston rings and the cylinder walls, ensuring smooth sliding and sealing; piston lubrication isn’t a separate system for the crankcase; valve lubrication is for the intake/discharge valves, not the crankcase. So the lubrication system used for the crankcase is crank case lubrication.