WinGD X72DF, Руководство по установке

Страница: 129 / 237

Marine Installation Manual 2021-08 4-54
4 Ancillary Systems
4.4 Fuel gas system
X72DF
4.4.7 Off-engine gas valve unit
Before being supplied to the engine, the fuel gas passes through the Gas Valve
Unit (GVU), which is a module connected to the engine’s fuel gas supply piping.
This unit controls the fuel gas pressure to the engine depending on the engine
load. As a safety precaution to ensure the tightness of valves and proper func
-
tioning of components, the GVU performs a gas leakage test before the engine
starts operating on fuel gas.
WinGD supports two different types of gas valve units:
GVU without housing
The GVU without housing, e.g. GVU-OD
™
(open design) from Wärtsilä (see
Figure 4 - 33 ), must be installed in an explosion-proof GVU room.
GVU within a housing
The GVU within a housing, e.g. GVU-ED
™
(enclosed design) from Wärtsilä
(see Figure 4 - 34,  4-55 ), is a solution where all the equipment is mounted inside
a gas-tight casing. This arrangement minimises installation costs, as it allows the
GVU-ED
™
to be placed inside the engine room, next to the engine in a similar
manner as other auxiliary equipment.
GVUs from other suppliers can be applied if fulfilling the same functionalities as
specified in this document. For dimensional GVU drawings or for further infor
-
mation on the product, please contact the GVU supplier.
Figure 4 - 33 The GVU-OD ™ from Wärtsilä
Forced engine room ventilation Gas safe area
Gas hazardous area
Annular pipe / GVU room venting
Gas detector
Gas venting pipe
Double-wall fuel gas pipe
air lock
Control room
GVU room
GVU
control
Ex Zone 1
Piston underside gas detection Gas pipe venting
inerting
from fuel gas
supply system
SM-0076