Pneumatic Systems and Schematics Flashcards
6 cards from real Millwright Certification practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Pneumatic Systems and Schematics flashcards as text
What is the purpose of a pneumatic time delay valve in an automation circuit?
Answer: To provide a controlled time delay between a pilot signal and valve actuation using an air reservoir and orifice
A pneumatic time delay valve uses a small reservoir that fills or exhausts through an adjustable orifice, creating a controlled time delay before the valve shifts, enabling sequential machine operations.
How does a dual-pressure (AND) valve function in a pneumatic safety circuit?
Answer: It outputs pressure only when both input ports simultaneously receive pressure signals
A dual-pressure valve (AND function) requires pressure at both inputs before it passes air to the output, commonly used in two-hand safety controls to ensure both operator hands are clear of the hazard zone.
What is the main advantage of using a rotary actuator instead of a cylinder with a rack-and-pinion mechanism?
Answer: Compact design providing direct rotary motion without converting from linear motion
Rotary actuators produce angular motion directly in a compact package, eliminating the complexity, space requirements, and potential backlash of converting linear cylinder motion to rotation through racks and pinions.
Why should pneumatic system piping be installed with a slight downward slope away from the compressor?
Answer: To allow condensed water to drain by gravity to collection points with automatic drains
Sloping the piping (typically 1-2% grade) toward drain points allows water that condenses in the distribution piping to flow by gravity to low-point drains rather than accumulating and being carried to pneumatic equipment.
What determines the force output of a pneumatic cylinder?
Answer: The bore diameter and the applied air pressure
Pneumatic cylinder force equals the piston area multiplied by the applied pressure (F = P x A). Larger bore means more area and more force; higher pressure also increases force output.
What safety precaution must be taken before working on a pneumatic system?
Answer: Isolate the air supply, bleed all stored pressure from lines and actuators, and lock out the energy source
Compressed air stores significant energy that can cause violent actuator movement or flying components. All pressure must be bled from lines, cylinders, and receivers, and the air supply must be locked out before maintenance.