🔍 Key Concepts

• Viscosity and movement – how a thick (viscous) fluid affects the motion of moving parts that must open and close quickly • Reciprocating compressor valves – why they need to respond rapidly and freely to pressure changes • Valve damage vs. sluggish operation – the difference between protecting the metal and slowing the valve action

💭 Think About

• Picture the valve disk and seat: if a sticky film is between them, does it make it easier or harder for the valve to unseat and reseat quickly? • In a low‑pressure air compressor, are valves more sensitive to extra resistance to motion, or do they benefit from added damping? • Which choice would most likely lead to reduced compressor efficiency or improper timing of suction/discharge?

✅ Before You Answer

• Decide whether a viscous film tends to speed up or slow down motion between two flat surfaces in close contact • Ask yourself if good compressor valves are designed to move freely with minimal resistance, or with deliberate drag • Rule out any option that suggests the oil has no effect or is purely beneficial without any trade‑off in valve responsiveness