Air Starting Sytem Q3-5

Question 1

What are the FOUR reasons for a reciprocating compressor taking too long to fill the main air starting bottles?

Answer 1

• Dirty or obstructed Air intake filter elements
• Leaking air start manifold
• Intercoolers blocked
• Stage drain, or automatic drain valve faulty

Question 2

What are FOUR safety devices fitted to the air starting system of a large marine diesel engine?

Answer 2

• Bursting disc, safety valves on every branch of the air start manifold
• Pressure relieving safety valves on intercoolers, after-coolers
• Safety valves on main air start bottles
• Bursting diaphragm on air compressor cooling jacket

Question 3

Describe a protective device fitted to the water side of an intercooler or after-cooler.

Answer 3

Pressure relief valve/pressure safety valve
The device can be used manually or automatically. To manually open the device, you would use the handle. If set off automatically, the spring will be pushed by the pressure, resulting in the valve opening and allowing the pressure to escape, lowering the pressure in the system.

Question 4

Why is the protective device fitted to the water side of an intercooler or after-cooler?

Answer 4

This device is fitted to relieve pressure in the case of an air tube leak or cracked cylinder liner inside the air compressor.

Question 5

What are the possible consequences if the protective device fails to operate?

Answer 5

If this device fails to operate, it could result in an overpressure in the water-cooling jacket, potentially causing a rupture of the air compressor.

Question 6

What are the main components of a two-stage main starting air compressor?

Answer 6

Cooler, Relief Valve, Auto Drain, High Temp Cut Out, LP Relief Valve, Filter, Crankshaft