This section is available on request - MAN Diesel & Turbo

MAN B&W 5.18
Servo oil system for VBS type CP propeller
The design principle of the servo oil system for
MAN Diesel’s Alpha VBS type CP propeller <strong>is</strong>
shown in Fig. 5.18.05.
The VBS system cons<strong>is</strong>ts of a servo oil tank unit,
the Hydraulic Power Unit, and a coupling flange
with electrical pitch feedback box and oil d<strong>is</strong>tributor
ring.
The electrical pitch feedback box continuously
measures the position of the pitch feedback ring
and compares th<strong>is</strong> signal with the pitch order signal.
Servo
p<strong>is</strong>ton
Zinc
anode
Stern
tube oil
tank
Monoblock
hub
Fig. 5.18.05: Servo oil system for MAN Diesel’s Alpha VBS type CP propeller
MAN B&W S70MC, S70MC-C/ME-C/ME-GI, L70MC-C/ME-C,
S60MC, S60MC-C/ME-C/ME-GI/ME-B, L60MC-C/ME-C,
S50MC, S50MC-C/ME-C/ME-B, S46MC-C/ME-B, S42MC,
S40MC-C/ME-B, S35MC, S35MC-C/ME-B, L35MC, S26MC
Oil tank
forward
seal
Lip ring seals
Stern
tube
Propeller shaft
Oil d<strong>is</strong>tribution
ring
MAN Diesel
Page 4 of 8
If deviation occurs, a proportional valve <strong>is</strong> actuated.
Hereby high pressure oil <strong>is</strong> fed to one or the
other side of the servo p<strong>is</strong>ton, via the oil d<strong>is</strong>tributor
ring, until the desired propeller pitch has been
reached.
The pitch setting <strong>is</strong> normally remote controlled,
but local emergency control <strong>is</strong> possible.
Hydraulic Power Unit
LAL
Hydraulic
pipe
TI
TAH
PI
Drain
tank
PAH
PAL
PSL
M M
PAL
Pitch
feedback
PSL
M
PI
Pitch
order
M
178 22 38�4.1
198 46 95�3.5