The number and the capacity of the air vessels for propulsion engines depend on the
requirements of the classification societies and the type of installation.
It is recommended to use a minimum air pressure of 1.8 MPa, when calculating the required
volume of the vessels.
The starting air vessels are to be equipped with at least a manual valve for condensate drain.
If the air vessels are mounted horizontally, there must be an inclination of 3...5° towards the
drain valve to ensure efficient draining.
Fig 8-3
Starting air vessel
Weight
[kg]
Dimensions [mm]
Size
[Litres]
D
L3
1)
L2
1)
L1
170
324
110
243
1807
125
200
480
110
243
1217
180
274
480
110
243
1767
250
450
480
133
243
3204
500
1)
Dimensions are approximate.
The starting air consumption stated in technical data is for a successful start. During start the
main starting valve is kept open until the engine starts, or until the max. time for the starting
attempt has elapsed. A failed start can consume two times the air volume stated in technical
data. If the ship has a class notation for unattended machinery spaces, then the starts are to
be demonstrated.
The required total starting air vessel volume can be calculated using the formula:
where:
total starting air vessel volume [m
3
]
V
R
=
normal barometric pressure (NTP condition) = 0.1 MPa
p
E
=
air consumption per start [Nm
3
] See Technical data
V
E
=
required number of starts according to the classification society
n =
maximum starting air pressure = 3 MPa
p
Rmax
=
8-4
Wärtsilä 20 Product Guide - a13 - 6 September 2016
Wärtsilä 20 Product Guide
8. Compressed Air System
Содержание WARTSILA 20
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