Post on 22-Oct-2014
By ShashankMech –B
Roll No. -82Reg No.- 080909328
INTRODUCTIONLarge Marine Diesel Engines are started
using high pressure compressed air. To minimise the risk of an air start
explosion, fuel is not injected into the cylinder whilst the air is being admitted.
There is a means to start the engine locally as well as from The Bridge .
International Association of Classification Society rules state
To protect starting air mains against explosion arising from improper functioning of starting valves
i. An isolation non-return valveii. A bursting disc or flame arrester
Different Parts at a glance
Air start valve When opened by the air signal from the distributor, compressed air at flows into the cylinder, forcing the piston down.
Bursting disk 1. A FLAME TRAP can also be used.2. Limits any pressure rise due to explosion by bursting.
Automatic valve Open only during air startingIncorporates
1. Non return valve 2. Slow turn valve
Air distributor One end attached to air main start valveHas number of pilot valvesOperated by means of a cam
Turning Gear Interlock If the turning gear is engaged ,this stops high
pressure air from reaching the air start control valve and thus the automatic valve
Air Start ReceiversCapacity of the receiversFunction of the receiverPressure gauge and drain are attachedManhole for inspection purposes
Air compressorsCharges the air receivers .Usually two stage reciprocating with inter
and after stage cooling are used. Relief valves are fit to each stage as is a high
temperature cut out.Intercoolers are fitted with taps on the water
side.
Thank You