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<\/p>\n<\/p>\n
(1) Function of a lubricant ?<\/strong> (2) Types of Lubrication<\/strong><\/p>\n Hydrodynamic – Full fluid film lubrication. (3) Properties of crankcase lube oil ?<\/strong> (4) What is viscosity<\/strong> (5) What is viscosity index ?<\/strong> (VI) (6) What is a pour point ?<\/strong> (7) What is the flash point ?<\/strong> Why flash point is important ?<\/strong> Average Closed Flash Points<\/strong> (8) What is TAN and TBN ?<\/strong> TBN for an oil used for-<\/strong> (9) What type of engine are using high TBN and why ?<\/strong> (10) What are detergency \/ dispersancy ?<\/strong> (12) Essential factor effecting the establishment of hydrodynamic lubrication ?\u00a0<\/strong> (13) Where do locate ME LO sump and its fitting ?<\/strong> (14) Why magnetic fitter is fitted on LO system ? Where fitted ?<\/strong> (15) Contaminants in the lube oil ?<\/strong> (16) Water contamination in lube oil ?<\/strong> Effects<\/strong> – Reduce cooling efficiency. Remedies<\/strong> – Proper purification with minimum throughput (17) Fuel dilution in lube oil ?<\/strong> Effects<\/strong> \udbc0\udcd6Fuel dilution usually diesel oil. How to move contaminants<\/strong> What will you do if LO is contaminated with FW or SW ?<\/strong> \udbc0\udc40 Firstly take the immobilization permit from the port authority. (19) When periodic batch purification make ?<\/strong> (20) What is grease ?<\/strong> (21) What is solid lubrication ?<\/strong> (22) At what point will feed to the piston ?<\/strong> (26) What will be happen temp: is lower than pour point ?<\/strong> (27) Why viscosity is important ?<\/strong> (28) How to maintain L.O on board ?<\/strong> (30) Action of L.O temperature abnormally high (What will you do as 2\/E, if M\/E L.O temperature abnormally high)<\/strong><\/p>\n \u2666\u00a0Inform bridge & reduce engine speed – Quick response. \u00a0Action when\u00a0 L.O level increase?<\/strong> (32) Action when decrease L.O level<\/strong> Possible leakage points<\/strong>: (33) Action when decrease L.O pressure?<\/strong> TYPES OF LUBRICATION?<\/strong> Boundary lubrication<\/strong> Hydrostatic lubrication<\/strong> Elasto-hydrodynamic lubrication<\/strong> What If LO is contaminated with SW?<\/strong> Difference in Cylinder oil and System oil<\/strong> L.O on board test<\/strong> \u2666Insoluble Content \u2666Water and other Contaminants \u2666Acidity \/ Alkalinity Determination \u2666Another method is: \u2666Foreign Particles Test The advance ferrography method was added to the PFA (Progressive Fast Analysis) programme where all samples pass through the combination of two machines, a particle quantifier (PQ) and a rotary particle depositor (RPD). These test measures the induced magnetic moment of debris as deposited on a substrate or contained within a specific volume of liquid. (1) Function of a lubricant ? \u2666 Separate entirely the working surfaces, thus reducing static and dynamic friction to a minimum and preventing wear. \u2666\u00a0Remove heat, generated either within the bearing or from an out side source. \u2666\u00a0Protect against corrosion \u2666\u00a0Flush away contaminants. \u2666\u00a0Dampen noise. \u2666\u00a0In some case; act as a sealant. (2) Types of […]<\/p>\n","protected":false},"author":1,"featured_media":5846,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[79],"tags":[],"class_list":["post-5845","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-marine-engineering-competency-exams-study-blogs"],"_links":{"self":[{"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/posts\/5845","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/comments?post=5845"}],"version-history":[{"count":5,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/posts\/5845\/revisions"}],"predecessor-version":[{"id":5852,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/posts\/5845\/revisions\/5852"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/media\/5846"}],"wp:attachment":[{"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/media?parent=5845"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/categories?post=5845"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/seadonna.com\/blog\/wp-json\/wp\/v2\/tags?post=5845"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\n\u2666 Separate entirely the working surfaces, thus reducing static and dynamic friction to a minimum and preventing wear.
\n\u2666\u00a0Remove heat, generated either within the bearing or from an out side source.
\n\u2666\u00a0Protect against corrosion
\n\u2666\u00a0Flush away contaminants.
\n\u2666\u00a0Dampen noise.
\n\u2666\u00a0In some case; act as a sealant.<\/p>\n
\nBoundary – Thin film lubrication
\nHydrostatic – Thick film lubrication
\nElasto-hydrodynamic – Thin film or square film lubrication.<\/p>\n
\n\u2666 Viscosity (Suitable) \u2666 Viscosity index (High)
\n\u2666\u00a0Pour Point (low) \u2666 Flash point (high)
\n\u2666 Oxidation stability \u2666 Carbon residues (low)
\n\u2666\u00a0Total acid number (TAN) + Total basic number (TBN)
\n\u2666\u00a0Detergency \u2666 Dispersancy<\/p>\n
\n\udbc0\udc40 A measure of its internal resistance to flow.
\n\udbc0\udc40 Viscosity of oil changes with temperature, falling when temperature rises and vice versa.
\n\udbc0\udc40 Crankcase L.O \u2013 130 to 240 seconds, Redwood No-1 at 60\u00b0C.
\n\udbc0\udc40 For cylinder oil, viscosity is 12.5 \u2013 22 Cst<\/p>\n
\n\u2666\u00a0The rate of change of viscosity of an oil in relation to change of temperature.
\n\u2666\u00a0Low viscosity index has greater change of viscosity with change in temperature than the oil of high VI.
\nGood crankcase oil = VI scale is 75 to 85.
\nFor cylinder Oil, VI is 85
\n\u2666\u00a0Highest VI of mineral oils is about 115 and with special additives, this may be raised to about 160
\n\u2666\u00a0Hydraulic oils, used in remote control hydraulic circuits must have very high VI; otherwise erratic response to the controls can be troublesome (Telemotor hydraulic system oil has VI of 110)<\/p>\n
\n\u2666\u00a0It\u2019s the lowest temperature at which an oil will barely flow.
\n\u2666\u00a0Pour point indicates that oil is suitable for cold weather or not.
\n\u2666\u00a0Pour point of engine crankcase should be -18 \u00b0C<\/p>\n
\nIt is the lowest temperature at which the oil will give off a sufficient inflammable vapour to produce a flash when a small flame is brought into the surface of the oil.
\nClose flash point for crankcase LO is around 220 \u00b0C.<\/p>\n
\nFO<\/strong> \udbc0\udcd6 It is important, fuel oil flash point is to be fairly high because of they were low, there would be a possibility of fire in storage.
\nLO<\/strong> \udbc0\udcd6 Engine crankcase oil flash point should be as high as possible to prevent crankcase explosion.
\n(For safe storage) to limit the oil storage tank heating temperature at least 14 \u00b0C lower than its F.P prevent fire.<\/p>\n
\nPetrol<\/strong> = -20 \u00b0C 70cSt Fuel Oil = 71 \u00b0C
\nParaffin<\/strong> = 40 \u00b0C Lube Oil = 220 \u00b0C
\nDiesel Oil<\/strong> = 65 \u00b0C<\/p>\n
\nIt is the neutralization value of used engine lube oil.
\nThe ability of an oil to react with a base reagent which indicates the acidity expressed as TAN.
\nThe ability of an oil to react with acidic reagent which indicate the alkalinity expressed as TBN.
\nThe results are expressed intern of milligrams of potassium hydroxide (KOH) required to neutralise one gram of sample oil for both TAN and TBN.<\/p>\n
\nCrosshead type diesel engine crankcase is 8mg KOH\/gram of oil.
\nFor trunk type engine using heavy oil is 30mg KOH\/gram of oil.<\/p>\n
\nAt trunk type engine using heavy fuel oil if blow pass occur incomplete combustion products reach directly into the crankcase and may cause the contamination with acid easily. Thus in this type of engine to neutralize the acid contamination must be used high TBN oil.<\/p>\n
\nIt is a chemical compound called detergent which has property of preventing the deposition of carbonaceous deposit and wash away with the lube oil.
\nDispersant additive addition is made to divide the larger size deposits into tiny particles to be carried in a colloidal suspension evenly throughout the bulk of oil.<\/p>\n
\n\u2666\u00a0Viscosity of oil
\n\u2666\u00a0Load acting on the bearing
\n\u2666 Surface smoothness of moving parts
\n\u2666 Speed of rotating
\n\u2666 Continuous LO supply
\n\u2666 Bearing clearance, bearing length and pin diameter.
\n\u2666 There must be convergence between fixed end and moving surface.<\/p>\n
\nIt is located under the engine in the ship double bottom and surrounded by cofferdams.
\nIt consist of 1) level gauge 2) man holes 3) air vent pipe 4) sounding pipes 5) heating steam coils 6) suction pipe and 7) valves for LO p\/p and purifier.<\/p>\n
\n\udbc0\udc40 To prevent pump damage due to ferrous metal particles.
\n\udbc0\udc40 Screw p\/p used in LO oil system is working in very fine clearance thus to prevent entering the small ferrous particles into the p\/p.
\n\udbc0\udc40 Magnetic fitter is fitted prior to the main circulation LO p\/p.<\/p>\n
\n\u2666 \u00a0Contamination of fresh Water (JW leaking)
\n\u2666 \u00a0Contamination of SW (Cooler leakage)
\n\u2666 \u00a0Contamination of fuel (Poor Atomisation, Unburned Fuel)
\n\u2666 \u00a0Oxidation products (High Exhaust Temperature, Burned Cyl Oil, Carbon from incomplete combustion)
\n\u2666 \u00a0Products of fuel combustion
\n\u2666 \u00a0Foreign mineral matters (Scale formation, Wear and tear)
\n\u2666\u00a0 Bio logical contamination.<\/p>\n
\nCauses<\/strong> 1) condensation of water vapour within the crankcase
\n2) Leakage from the cooling water system for cylinder or piston
\n3) Leakage from the sump tank heating steam coils.<\/p>\n
\n– Increase the acid formation in trunk type piston engine.
\n– Can cause corrosion on m\/c parts.
\n– Microbial degradation, [Reduce centrifuging efficiency; promote local pitting and corrosion]
\n– Reduce load carrying capacity
\n– Reduce L.O properties, and TBN of oil
\n– Form sludge due to emulsification<\/p>\n
\n– Batch purification if heavy contamination
\nMaximum Allowable % of water in LO
\nFor crosshead engine, < 0.2 % is satisfactory
\nIf water content exceed 0.5 ~ 1.0 %, immediate action should be taken
\nIf > 1%, engine can be damaged
\nFor trunk type engine, < 0.1% is satisfactory
\nIf > 0.5 %, immediate action should be taken and
\nIt is maximum permissible content<\/p>\n
\nCauses<\/strong> \udbc0\udcd6 Poor atomization of a fuel injector and back leak through the fuel injector p\/p plunger and barrel.<\/p>\n
\n\udbc0\udcd6Lower viscosity and low fresh point
\n\udbc0\udcd6Lower viscosity LO reduces this properties ( e.g load carrying capacity )
\n\udbc0\udcd6Lower fresh point will case crankcase explosion.<\/p>\n
\nFiltering – Removed large oil insoluble matter
\nGravity separation – Heavy matters, sludge and water
\nAdding special additives – Reduce acids, sludge, finer oil insoluble matter
\nCentrifuging – Sludge, foreign matter and water
\nWater washing – Only for straight mineral oil or oil without additives, can removeacids.<\/p>\n
\n\u2666 \u00a0Batch Purification must be done
\n\u2666 Renovating Tank heating and regular draining
\n\u2666 For SW contamination, Water Washing is required
\n\u2666 Sump to be opened and thoroughly wipe out.
\n\u2666 How do you make batch purification ?<\/p>\n
\n\udbc0\udc40 The entire oil charge should be pumped by the purifier or by main circulation p\/p into renovating tank.
\n\udbc0\udc40 It should be allowed to settle for at least for 24 hours with heating about 60\u00b0C (60\u00b0C).
\n\udbc0\udc40 Water and sludge should be drained out periodically.
\n\udbc0\udc40 Cleaned the interior of the sump tank and carefully examined.
\n\udbc0\udc40 The oil should be passed through the purifier at its optimum efficiency and than pump back into the sump tank.
\n\udbc0\udc40 When sump tank empty, its interior should be cleaned and exaimed.<\/p>\n
\n\udbc0\udc40 If the oil is suspected from containing strong acids,
\n\udbc0\udc40 High insoluble contents due to poor combustion or water due to leak cooling system.
\n\udbc0\udc40 It is also made at least once a year when cleaned and examined for sump tank.<\/p>\n
\n\udbc0\udc40 It is a semisolid lubricant consisting of high viscosity mineral oil and metallic soap with filler.
\n\udbc0\udc40 Metallic soaps are compound of Ca, Na, Al.
\n\udbc0\udc40 Filler are lead, zinc, graphite and molybdenum.<\/p>\n
\n\udbc0\udc40 Grease lubrication<\/p>\n
\n\udbc0\udc40 The cylinder oil is feed to the piston at the time when the top two piston rings pass the lubrication holes in the cylinder during the piston stoke.
\n\udbc0\udc40 It is a limited lubrication.<\/p>\n
\nThe oil can not freely flow thus effect the pumping system (lubrication system)<\/p>\n
\nFO<\/strong> \udbc0\udcd6 Low viscosity is required for fuel in order to obtain good atomization at fuel valve.
\nLO<\/strong> \udbc0\udcd6 LO must be chosen which has a suitable viscosity for the working temperature for efficient lubrication.<\/p>\n
\n\u2666\u00a0L.O onboard test is carried out regularly.
\n\u2666\u00a0Regular cleaned L.O line filter.
\n\u2666\u00a0L.O purifier should be run during ship is in sea
\n\u2666\u00a0Maintain L.O purifier performance
\n\u2666\u00a0Periodic batch purification must be carried out & cleaned L.O sump tank once a year
\n\u2666\u00a0Maintain L.O temperature within receptacle limit
\n\u2666\u00a0Maintain good L.O cooler efficiency
\n\u2666\u00a0Keep good fuel combustion system
\n\u2666\u00a0Why cooler is installed after filter ?
\nIt is more effective to filter the hot oil, as pressure drop through the filter is less and filter is more complete.<\/p>\n
\n\u2666\u00a0Check engine overload or not (Exhaust temp:, fuel rack,..)
\n\u2666\u00a0Check L.O sump & L.O cooler & L.O purifier temperature (set value)
\n\u2666\u00a0Check L.O sump tank heating valve.
\n\u2666\u00a0Shut L.O cooler by-pass totally after stopping (or) too high temperature not fall
\n\u2666\u00a0Clean L.O cooler
\n\u2666\u00a0Check sump tank heating coil leakage
\n\u2666\u00a0Make L.O onboard test (esp Viscosity)
\n\u2666\u00a0Check L.O piping system leakage or blockage
\n\u2666\u00a0Make (inspection & check bearing clearance & loosing attachment
\n\u2666\u00a0Check ampere (or) load when turn the turning gear<\/p>\n
\n\u2666\u00a0Check piston cooling system (water)
\n\u2666\u00a0Check L.O purifier (gravity disc is correct or not) [L.O purifier water outlet sight galss]
\n\u2666\u00a0Check filling valve from storage tank
\n\u2666\u00a0Check L.O cooler\/although oil pressure is greater than S.W pressure.<\/p>\n
\n\u2666<\/strong>\u00a0Check rate of decreasing if slowly decrease, fill up L.O and find the leakage without stopping engine
\n\u2666\u00a0If rapidly decrease, inform to bridge and stop the engine. Find the leakage and repair.<\/p>\n
\n\u25ca Bed plate crack (check engine room bilge)
\n\u25ca\u00a0Piston cooling L.O system (check scavenge space & under piston space {entablature})
\n\u25ca\u00a0L.O cooler & L.O purifier
\n\u25ca\u00a0All pipes and connection
\n\u2666\u00a0Check L.O return valve from crankcase to sump tank close or not
\n\u2666\u00a0Check oil scraper rings & stuffing box<\/p>\n
\n\u2666\u00a0Start stand by pump
\n\u2666\u00a0Change & clean L.O filter
\n\u2666\u00a0After engine stopping, check bearing clearance and L.O pipe connection
\n\u2666\u00a0Check L.O pump discharge & suction pressure
\n\u2666\u00a0Check L.O temperature<\/p>\n
\nHydrodynamic lubrication (full fluid film)<\/strong>
\n\u2666\u00a0Moving surfaces are separated completely by the pressure of a continuous unbroken film or a layer of lubricant, generated by the movement of the two surfaces relative to each other.
\n\u2666\u00a0Essential requirement is formation of a wedge of lubricants between surfaces.
\n\u2666\u00a0Thickness of film 0.025 \u2013 0.10 mm.
\n\u2666\u00a0Lubrication for Journal Bearing, Bottom End Bearing, Tilting Pad Thrust Bearing<\/p>\n
\n\u2666<\/strong>\u00a0It exists when a full-fluid film lubrication is not possible.
\n\u2666\u00a0The sliding surfaces are separated by only a thin film of lubricant.
\n\u2666\u00a0High friction between the surfaces and some degree of metal to metal contact occurs
\n\u2666\u00a0Lubricant oil film decreases, until asperities of mating surfaces touch<\/p>\n
\n\u2666\u00a0A form of thick film lubrication, but instead of being self- generated, it is supplied from an external source by oil under pressure from a pump.
\n\u2666\u00a0Lubrication for Crosshead Bearings, with attached pump.<\/p>\n
\n\u2666\u00a0Applies to line contact or nominal point between rolling or sliding surfaces, such as rolling contact bearings and meshing gear teeth.
\n\u2666\u00a0Thin film or squeeze film lubrication limits metal to metal contact.
\n\u2666\u00a0Elastic deformation of the metals occurs, and there is effect of high pressure on the lubricant.<\/p>\n
\n\u2666When sump oil is contaminated with SW, find sources of leakage (may be from LO cooler during ME stopped) stoppage and rectified
\n\u2666\u00a0In port or while ME is stopped, transfer contaminated oil through purifier or transfer pump into Renovating Tank, settled for at least 24 hours at about 60\u00b0C, and water and sludge drained out periodically
\n\u2666\u00a0Oil passed through purifier at 78\u00b0C with optimum efficiency, and pump back to Renovating Tank
\n\u2666 When sump tank is empty, interior cleaned and examined
\n\u2666\u00a0Purified oil sent to laboratory and tested
\n\u2666\u00a0During this time, new oil should be used
\n\u2666\u00a0Oil should be reused, if lab results recommended that it is fit for further use. (Straight mineral oil 3% water washed. Additive oil1% water washed)<\/p>\n
\n\udbc0\udc40 Cylinder oil is detergent \/ dispersant oil
\n\udbc0\udc40 System oil is straight mineral oil<\/p>\n
\n\u2666 Viscosity Determination
\nThe simplest method is three tube rolling ball viscometer
\nAssuming the oil in the engine to be SAE 30 grade, one tube is filled with minimum safety viscosity (about SAE 20) and another one filled with maximum safety viscosity (about SAE 40). The last tube is to be filled with test sample.
\nAll tubes are placed in a bucket of warm water until the oils are at the same temperature. The three tubes then mounted on a tilted board and inverted. An internal hollow ball in each tube then rises to the surface.
\nIf the time taken in the test sample is between that of the lower and upper limit oils, the oil is fit for further use. If not, it must be replaced.<\/p>\n
\nA drop of sample oil is released from a given height onto a special filter paper. Compare the result with the known varying insoluble content. The upper limit for straight mineral oil is 1% to 1.5 % and for detergent dispersant oil is 5%.<\/p>\n
\nA known amount of sample oil in the test tube is heated and must be shaken the while doing so
\n1) If there is no cracking, the oil is dry
\n2) If there is slightly cracking, the oil having a trace of water
\n3) If there is a heavily crackling, the oil is heavily diluted with water<\/p>\n
\nAcidity is tested by extracting the acids from the sample by means of shaking with a known amount of distilled water. The acidic extract is then placed on a watch glass with an indicator solution of known strength. The mixture is then drawn up into a glass tube and its colour compared with a series of colour standards, each representing a known PH value, from which the sample can be determined quite accurately.<\/p>\n
\nA drop of indicator solution is placed on to blotting paper and this is followed by a drop of sample oil placed at the centre of the drop of previous absorbed indicator.
\nIf the change of colour is Red, it is acid
\nIf blue\/green, it is alkaline.
\nIf yellow\/green, it is neutral.<\/p>\n
\nThis can be done by either Spectrochemical analysis or Ferrographic analysis or Ferrographic analysis, each giving particle size less than 10 uM to 100 uM range depending on the tests applied.
\nThe most powerful technique is Inductively coupled plasma atomic emission spectrometry (ICP OR PES), which uses a direct spray technique to determine the wear and contaminant elements present in the oil. This technique will in the main only detect the particles below 10 uM size.
\nIn ferrographic test, the sample is thinned first with some solvents and allowed to pass slowly down a slide surrounded by powerful magnetic field.
\nThen it is examined by special microscope with red and green filters under lights. The shape of the particles is used to identify the source of the wear debris.<\/p>\n
\nThese machines provide accurate test by rotating the metal particles and then separating into three different sizes, Theses three bands of particles are examined by very powerful microscope to determine the type of materials and shape.
\nIf more detailed examination is necessary, the debris may be subjected to a scanning electron microscope.<\/p>\n","protected":false},"excerpt":{"rendered":"