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A Guide To Lube Oil Purifier
A ship has hundreds of machinery and systems which helps in its day to day operations.
Lubrication plays a vital role in smooth running of these machineries by overcoming and reducing heat, neutralizing acid combustion by-products, preventing scuffing, lessening friction and thereby combating wear and tear between two running surfaces.
The main engine lube oil system on ships ensure lubrication of the main bearings through pumping of lube oil by duplex oil filters, to the crossheads, and guides, piston cooling and bottom end bearings through the swivel jointed pipes in the engine casings.
The engine cylinders have their own lube oil system, which lubricates the surfaces between the cylinder wall and the piston rings through a set of concentric nozzles or quills fitted around the cylinder liner.
It is imperative to maintain the lubricating oil’s properties and to ensure it is in good condition.
This is executed by the watchkeeping engineer who is responsible for carrying out proficient engine room watch especially, on lube-oil temperature, pressure and the condition of oil.
The common contamination of the lube oil can occur because of:
Jacket Water Leaking
Cooler Leakage
Fuel Contamination through Poor Atomization of fuel and unburnt fuel.
High Exhaust Temperature, Burned Cylinder Oil, Carbon from incomplete combustion and products of fuel composition
Scale formation, wear and tear and biological contamination.
Such contamination need to be purified to maintain the quality of lube oil throughout as the quality of lube oil determines equipment lifetime and its productivity.
As impure lube oil leads to:
Reduction in fuel efficiency.
Corrosion on mechanical parts.
Increase in acid formation in trunk type piston engine.
Reduce Load Carrying capacity
Microbial Degradation
Case Crankcase Explosion.
Therefore, we need Lube oil purifier on ships for proper purification of lube oil with minimum throughput or batch purification in case of heavy contamination.
There are three ways in which lube oil purification can be done:
centrifugation,
filtration and
coalescence.
A high-speed centrifugal purifier is installed on a ship to get rid of the unwanted contaminants and pollutants from the lube oil.
On ships, separate marine purifiers are used for fuel and lube oil. Lube oil is purified only through centrifugation while the fuel oil uses both centrifugation and gravity separation.
On ships, it is also referred to as Centrifuge. It is a purifier that separates two liquid substances based on their difference in density with the use of gravity disc to separate solid and water and sealing water as an operator with two-holed lower discs; one for water and other for oil.
Construction Features of Centrifugal Purifier or “Centrifuge”:
Electric Motor: This is responsible for driving various components such as bowl, tachometer, gear-pump via pinion gear, and rotating counter.
Friction Clutch: Friction clutch is installed on the horizontal shaft to safeguard and protect the electric motor from damage as the complete purifier assembly is too heavy for a motor to take the full load from the start without overheating. Once the system attends a preset required momentum, the pads gradually move out under centrifugal force connecting the motor directly to the bowl. It is necessary for the friction clutch to engage with the drum for the revolution of the bowl.
It safeguards against heavy starting current. A solid coupling, then due to a large starting current, would simply overheat and burn the motor winding. Therefore, friction coupling allows for some time, and after the motor reaches a certain RPM, the coupling gets engaged thereon.
Gear Box: The Gear Box Assembly in Marine Lube oil Centrifugal purifier consists of a motor shaft, friction clutch, the breaking lever, spur gear, worm gear and the attached gear pump.
The Bowl & Disc Stack: The Bowl is a solid assembly made up of high tensile steel working within purifier frame with ample space to accumulate and discharge sludge. Disc Stacks are incorporated with small holes to form the interface line and carry out separation using centrifugal force that causes oil to move inward and water and solid particle to move outward.
Dry Air Generator For Power Systems
Dry air generators are more unique in power systems for large transformers and reactors.
When the transformer is shipped out from the factory, the heavier insulating oil is extracted and replaced with light dry air, which reduces the transportation cost of the large transformer.
Due to the long maintenance and accident repair time of a large transformer, sometimes it is more than half a month. If there is no absolute dry air filled into the transformer continuously, the transformer body will be seriously wet and rusted, accordingly the transformer insulation performance will be destroyed.
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