Compressed Air Systems

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Compressed Air Systems
order up a two-can jam in the back of the
bus! - EM2(SS) Barrow
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Introduction

• Air systems are vital to ship operations
• Starting diesel and gas turbine engines
• Torpedo ejection
• Deballasting air (EMBT Blow)
• Prairie masker
• Compressed air represents stored energy - capable
  of doing work at a later point
• Used extensively both in high pressure and low
  pressure applications

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Air Compressors

• Used to compress air from inlet pressure (atm) to
  a higher pressure (PV a RT)
• Classified according to
• Type of displacement
• Staging
• Type of Drive (prime mover)
• Operating Pressure
• Capacity

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Air Compressors

• Type of displacement
• Positive used for high pressures
• Non-positive used for lower pressures
• Staging
• Number of compression steps used in compression
  process
• Type of drive system
• Classified according to prime mover (almost all
  electric motors)

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Air Compressors

• Operating (discharge) pressure
• Low (lt151 )
• Medium (151-1000 )
• High (gt1000 )
• Capacity
• Volume of air compressed
• CFM (cubic feet per minute)

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Non-Positive Displacement

• Centrifugal compressor
• Radial flow
• Axial Compressor
• Axial Flow

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Positive Displacement

• Reciprocating Piston
• Piston assembly with valves to control flow
• Can either be single stage or multi-stage

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Positive Displacement

• Rotary Compressor
• Rotary sliding vane (not used)
• Rotary impeller (low press/ high CFM
  applications)
• Liquid piston (not used much)

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Positive Displacement

• Rotary Compressor
• Rotary sliding vane (not used)
• Rotary impeller (low press/ high CFM
  applications)
• Liquid piston (not used much)

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Positive Displacement

• Rotary Compressor
• Rotary sliding vane (not used)
• Rotary impeller (low press/ high CFM
  applications)
• Liquid piston (not used much)

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Support Systems

• Cooling
• Most cooled by fresh water systems
• Remove heat from compression process
• Intercoolers used between stages
• Aftercooler used after final discharge
• Receivers
• Storage tanks for reserve air capacity
• Used on ALL compressors to lower pulsations
• Safety features
• Auto shutdown

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Specific Uses of Air

• High Pressure
• Torpedo Ejection
• Emergency Blow
• Hydraulics
• Remotely-operated valves
• Low Pressure
• Prairie Masker system
• Potable water
• Pneumatic tools valves

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Questions?