Compressed Air System Flashcards
Describe the flow of atmospheric air to the ship’s users.
Atmospheric Air > Air Compressor > Air Bottle > Distribution manifold > Users
State the following parameters about the air compressor:
Maximum working pressure
AUTO Settings (cut in & cut out)
L/O capacity
Auto Drain Timing
Safety relief pressure
Maximum working pressure: 40 bar
Cut-in: 27 bar Cut-out: 40 bar
L/O capacity: 5.2L
Auto Drain Timing: 15s every 15 minutes
Safety relief pressure: Stage 1 - 8 bar Stage 2 - 42 bar
What is the purpose of an auto drain system?
To remove condensate/water droplets formed inside the air compressor due to the pressure on the air
State the following parameters about the air bottle:
Capacity
Working Pressure
Safety Relief
Capacity 1000L
Working Pressure 40 bar max
Safety Relief 42 bar
What is the purpose of the air manifold? State the qty of each air manifold type in each engine room
Purpose: Distribute compressed air at the necessary pressure to different users
1 x 40 bar, 2 x 7 bar
State the purpose of the following valves in the air manifold:
Distribution Valves (2 purposes)
Reduction Valves
Safety Relief Valves
Distribution Valves: Serves as an isolating valve to respective users & an interconnecting valve between FWD & AFT air manifolds
Reduction Valves: Reduces compressed air pressure to a set pressure
Safety Relief Valves: To relief the air pressure if it builds 5% above manifold working pressure
State the 6 users (and qty) of the 7 bar manifold.
State how to distinguish which users use 7 bar manifold 1 & 3 and 7 bar manifold 2 & 4
- 9x S/C blow down
- 23x Service Air outlets
- F/W hydrophore tank
- Inflatable Shaft Seal (regulated to 2.5 bar, AFT E/R)
- Oily water separator(FWD E/R)
- F/O purifier control air
The users with qty/more than one are 1 &3, rest are 2 & 4
State the 6 users of the 40 bar manifold and the pressure they are regulated to (if have)
Service air manifolds (regulated to 7 bar)
Control air panel (regulated to 7 bar)
Gen start air (regulated to 7 bar)
Air horn (fwd E/R only)
M/E start air (regulated to 10 bar)
Adjustable tire air inflator (regulated to 10 bar)
State the uses of all the 9 valves in the Control Air Panel. (order must be correct)
- Gen 1 air flap shut off
- Gen 2 air flap shut off
- M/E mist detector vacuum p/p
- M/E fuel isolation v/v
- Gen 1 fuel isolation v/v
- Gen 2 fuel isolation v/v
- Gen 1 fuel blow down
- Gen 2 fuel blow down
- LT water v/v
When opening air valves, why must we open them slowly?
If air valves are opened too fast, the pipe on the lower pressure side could get damaged or burst due to suddenly taking a large pressure difference.
Valves must be opened slowly to gradually equalize the pressure.
How to drain the air bottle under normal circumstances?
Slowly open the drain valve at the bottom of the bottle and drain the condensate into the bilges.
How to quickly drain the air bottle in the event of an emergency? Why is an engine room fire a cause for emergency?
Air can be released to atmosphere (stbd funnel top) by opening v/v located at STBD AFT stairwell on 4th deck.
In the event of engine room fire, the highly-pressurized air bottle is extremely hazardous as it could explode under high heat.
State how to operate the air compressor manually and automatically.
3 steps for AUTO, 4 steps for MANUAL
Manual
- Switch Air Compressor LOP to “M”
- Press “Start” button. Green operation light will light up.
- Continuously man the unit and observe the air bottle pressure via pressure gauge on the air bottle/SCMMS pg. 15
- Once pressure reaches 40 bar, switch Air Compressor LOP to “O” to turn off compressor.
Auto
- Switch air compressor LOP to “A”
- Air compressor will cut-in at 27 bar and cut out at 40 bar
- Switch Air Compressor LOP to “O” to turn off the compressor at any time.
State the working pressure of the emergency air bottle (E-bottle).
State how to charge the E-bottle in normal circumstances and during a blackout.
Working pressure: 30 bar
Normal
- Open the isolating valves to the main airline. The E-Bottle will charge from the Main Air Bottle (regulated to 30 bar).
- Once the E-Bottle has been charged, close the respective valves.
During Blackout: Manual pump lever attached to E-bottle to pressurize air till sufficient compressed air to start generator.
What info of the compressed air system is available on SCMMS Pg 55?
Air Compressor ON/OFF
Air Compressor Failure
Air Bottle Pressure
System Diagram
