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MARINE ENGINEERING KNOWLEDGE
Wednesday, May 14, 2014
Sunday, February 23, 2014
Axial damper.
The engine is equipped with an integrated axial damper. The duty of the axial
damper is the reduction of axial vibrations.
The damper consists of an upper , and a lower cylindrical part , which are both
screw fastened to the last bearing girder, and of a damping flange which is a
part of the crankshaft. The oil quantity required for the damping is adjusted by
means of a throttling valve.
The engine is equipped with an axial damper monitoring system arranged above
the end casing at the free end.
The oil pressure in the aft side and fore side chamber
of the axial damper is monitored, and in case of oil pressure drop an alarm is
triggered (setting values see Alarms and Safeguards .
The reason for this alarm must be investigated and remedied:
Orifices in the pressure gauge pipes clogged
Shut-off valves closed in the pressure gauge pipes
Low oil pressure and / or high oil temperature in the bearing oil system
Throttle valve mal-adjusted
Excessive wear of the sealing rings, e.g. caused by dirt particles (clearance
too big).
damper is the reduction of axial vibrations.
The damper consists of an upper , and a lower cylindrical part , which are both
screw fastened to the last bearing girder, and of a damping flange which is a
part of the crankshaft. The oil quantity required for the damping is adjusted by
means of a throttling valve.
The engine is equipped with an axial damper monitoring system arranged above
the end casing at the free end.
The oil pressure in the aft side and fore side chamber
of the axial damper is monitored, and in case of oil pressure drop an alarm is
triggered (setting values see Alarms and Safeguards .
The reason for this alarm must be investigated and remedied:
Orifices in the pressure gauge pipes clogged
Shut-off valves closed in the pressure gauge pipes
Low oil pressure and / or high oil temperature in the bearing oil system
Throttle valve mal-adjusted
Excessive wear of the sealing rings, e.g. caused by dirt particles (clearance
too big).
Thrust Pads in RT flex
In fixed pitch propeller plants the respective execution for right hand or left hand
rotating engines has seven thrust pads on either side of the thrust bearing flange,
each adapted to the respective sense of rotation.
In controllable pitch propeller plants the thrust bearing is equipped on either
side with two thrust pads each for left hand and right hand rotation respectively
The thrust pads are lubricated with bearing oil which is led by lubricating oil pipe
to spray nozzles . The nozzles are dimensioned in such a way that in operation
an oil film forms between thrust bearing flange and thrust pads (hydraulic
wedge)
rotating engines has seven thrust pads on either side of the thrust bearing flange,
each adapted to the respective sense of rotation.
In controllable pitch propeller plants the thrust bearing is equipped on either
side with two thrust pads each for left hand and right hand rotation respectively
The thrust pads are lubricated with bearing oil which is led by lubricating oil pipe
to spray nozzles . The nozzles are dimensioned in such a way that in operation
an oil film forms between thrust bearing flange and thrust pads (hydraulic
wedge)
Friday, February 14, 2014
Hot Lay-up
In this lay-up condition, the machinery is kept
in operation for the sake of fast recommissioning,
but measures may be taken to
reduce various operational costs
Hot lay-up for up to one month
This lay-up condition is suitable for 24 hours
re-commissioning time. During this period, the
vessel complies with classification and flag
state requirements. The crew may be reduced
to the level as required by safe manning
certificate. Machinery will be kept running
with consideration to minimum consumption.
Normally no return on insurance fee applies
during the first 30 days idle.
Hot lay-up for up to three months
Insurance lay-up returns may be granted for
idle periods exceeding 30 days. If manning
reductions below safe manning certificate
limits are considered
Hot lay-up for up to twelve months
This condition is suitable for 1 week recommissioning
time. When the vessel is laid
up or otherwise taken out of service for a
period of more than 3 months, notifications on
lay-up should be issued to the classification
society and flag state. Manning may then be
reduced below the safe manning certificate
limit in agreement with the flag state, the
classification society, other local authorities
and insurance companies. Most port authorities
will have local requirements on laid-up
vessels, such as oil pollution coverage, wreck
removal or minimum manning.
ISM and ISPS certificates are still valid but
additional verification shall be performed to reinstate
both certificates upon recommissioning.
See Section 5 for details on
ISM and ISPS.
Friday, December 20, 2013
Thursday, December 19, 2013
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