Millwright Certification Pneumatic Systems and Schematics 2

Question 1

What is the function of the filter, regulator, and lubricator (FRL) unit in a pneumatic system?

Accepted Answer

To clean, regulate pressure, and add oil mist to the compressed air before it reaches downstream components

Answer

To increase the air compressor output

Answer

To store compressed air for peak demand

Answer

To convert pneumatic energy to hydraulic energy

Question 2

What causes water to accumulate in a compressed air system?

Accepted Answer

Compression raises air temperature, and subsequent cooling causes moisture in the air to condense

Answer

Leaking air cylinders

Answer

Worn compressor rings

Answer

Excessive lubricator oil output

Question 3

On a pneumatic schematic, how is a normally closed (NC) 3/2 solenoid valve represented in its de-energized state?

Accepted Answer

Pressure blocked, outlet connected to exhaust

Answer

Pressure connected to outlet, exhaust blocked

Answer

All ports open

Answer

All ports blocked

Question 4

Why are pneumatic systems considered inherently safer than hydraulic systems in certain environments?

Accepted Answer

Compressed air is non-flammable, non-toxic, and leaks do not create environmental contamination

Answer

Pneumatic pressure is always lower

Answer

Pneumatic components are stronger

Answer

Pneumatic systems never fail

Question 5

What is the purpose of a quick-exhaust valve in a pneumatic circuit?

Accepted Answer

To allow rapid venting of exhaust air directly at the actuator for faster retraction speed

Answer

To quickly fill the cylinder with air

Answer

To regulate the supply pressure

Answer

To prevent backflow in the air line

Question 6

What is the most common cause of sluggish or slow pneumatic cylinder operation?

Accepted Answer

Restricted flow from undersized tubing, clogged filters, or partially closed flow control valves

Answer

Excessive air pressure

Answer

Too much lubricator oil

Answer

Oversized cylinder bore