Final Test

Question 1

Why are pneumatic cylinder bodies built with lower structural strength material?

Answer 1

Pneumatic Cylinders operate at much lower pressure

Question 2

What would be the reason for actual performance to deviate from estimated values?

Answer 2

1. Air Compressibility
2. Air Leakage from the cylinder
3. Temperature changes causing pressure changes for the fixed chamber volume

Question 3

How would increasing the number of vanes in a pneumatic motor impact the following parameters?
Torque
Rotational Speed
Air Leakage
Friction between vanes and housing

Answer 3

Torque - Increases
Rotational Speed - Decreases
Air Leakage - Decreases
Friction between vanes and housing - Increases

Question 4

What is the minimum number of vanes in a pneumatic motor?

Answer 4

3

Question 5

What is the main difference between an anvil and a rod in a pneumatic cylinder?

Answer 5

The anvil is a metal part that is not connected to but is in contact with the piston at specific points of time. The anvil will only move forward if the piston hits it.

Question 6

List 3 conditions for selection of air intake locations in a pneumatic system

Answer 6

1. Avoid areas with dusty air
2. Shield intake from rain water
3. Shield intake from sunlight

Question 7

Classify the 3 intake-line filters in pneumatic systems

Answer 7

1. Dry
2. Oil Bath
3. Oil Wetted

Question 8

Define dew point

Answer 8

The temperature at which water becomes water droplets

Question 9

What happens when water drops below dew point?

Answer 9

The water will become water vapour and condense itself into a solid

Question 10

How does air temperature change along the working lines?

Answer 10

The temperature in the working lines decreases

Question 11

What are two issues resulting in the working lines caused by temperature drops?

Answer 11

1. Pressure Drop
2. Water Condensation

Question 12

How is centralized different from decentralized distribution systems?

Answer 12

• Centralized system has one compressor station that feeds multiple work stations
• Decentralized system has multiple compressors feeding 1 or 2 work stations

Question 13

List the 6 factors that contribute to pressure drop in pneumatic lines

Answer 13

• Absolute roughness
• Hydraulic Diameter
• Pipe Length
• Fluid Density
• Fluid Viscosity
• Average Flow Velocity

Question 14

List the factors required to size a receiver

Answer 14

• Compressor volume flow rate
• Min and Max compressor settings
• Compressor idle time
• Atmospheric Pressure

Question 15

What is compressor idle time?

Answer 15

The time it takes for the receiver to go from max pressure to min pressure

Question 16

List the 4 groups of distrubution systems in pneumatic systems

Answer 16

• Fixed piping: Centered grid system
• Fixed piping: De-centralized grid system
• Fixed piping: Loop System
  -Flexible hosed portable compressors

Question 17

What is the main advantage of loop distrubution system?

Answer 17

It runs parallel to the reciever which reduces flow speed but reduces pressure drop which then reduces power consumption then reducing operating costs

Question 18

How would pressure drop change with increasing air viscosity?

Answer 18

Increasing air viscosity will cause a larger pressure drop

Question 19

What are two techniques used in two-stage filters?

Answer 19

A two stage filter uses centrifuged and straight filtering to work

Question 20

Which two forces are required for an automatic draincock to open?

Answer 20

Air pressure and the weight of impurities filtered out

Question 21

What does FRL stand for?

Answer 21

Filter, Pressure Regulator and Lubricator