Aux 1 Unit 7 Q5 – Answer

Contaminants in Pneumatic Control Systems Air Supply

Here’s a look at three common contaminants in the air supply for pneumatic control systems and why they’re undesirable:

(a) Three Contaminants:

  1. Moisture (Water Vapor): This is a prevalent contaminant in compressed air systems.
  2. Solid Particles (Dust, Dirt): These can enter through leaks or from the environment.
  3. Oil (Lubricating Oil): Oil carryover can happen from compressors or from lubricated moving parts within the system.

(b) Why These Contaminants Are Undesirable:

  1. Moisture (Water Vapor):
    • Corrosion: Water reacts with metal components in valves, cylinders, and pipelines, leading to rust and premature wear.
    • Freezing: In cold environments, water can freeze and cause blockages or damage components.
    • Reduced Lubricity: Water weakens the lubricating film formed by condensed moisture in the system, increasing friction and wear.
  2. Solid Particles (Dust, Dirt):
    • Abrasion: Particles can cause wear and tear on internal components, reducing efficiency and lifespan.
    • Sticking Valves: Particles can jam or restrict movement in valves, affecting system operation.
    • Filter Clogging: Particles can clog filters, reducing air flow and potentially leading to pressure drops.
  3. Oil (Lubricating Oil):
    • Valve Malfunction: Oil can coat spools and seals in valves, causing them to stick or malfunction.
    • Contaminated System Components: Oil can contaminate downstream components like sensors and actuators, affecting their performance.
    • Fire Hazard: In some applications, oil contamination can create a fire hazard, especially near high-temperature components.