Sunday, February 23, 2014

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)

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.

Thursday, December 19, 2013

Replacing A Gauge Glass (+playlist)

Spectroscopy,metals analysis


Spectrographic metals analysis is usually the 'heart' of most oil analysis programs.  Using either a Rotrode Emission Spectrometer or an Inductively Coupled Plasma Spectrometer (ICP), 20 or more metals can be simultaneously determined.  The metals analyzed for include wear, additive, and contaminant metals and are reported in parts per million (ppm). 

Laboratories uses a Rotating Disk Emission Spectrometer. The instrument is quick and easy to operate and is accurate within acceptable limits.

The Rotrode Spectrometer has a particle size detection limitation of between 3µ and 10µ (depending on the particular metal in question and the amount of surface oxidation on the particle surface) compared to the .5µ - 2µ limitation of the ICP.  Results of the Rotrode Spectrometer are accurate to about 1 or 2 ppm. 
 Results of the ICP are accurate to .1 ppm.  The advantage of the Rotrode Spectrometer is that no dilution of the sample is required, while the advantage of the ICP is its accuracy.  With proper sample preparation, an ICP can measure in the 10's of parts per billion (ppb).  

Particle size limitations of an ICP are even more sever than a Rotrode Spectrometer because the sample and particles have to be nebulized.  If measuring very low concentrations, the diluent (usually diesel fuel) has to be at least as clean.