MARINE AUXILIARIES

Cont’ An oil purifier uses the same principle for separating dirt or water from oil. Instead of using gravity, it uses centrifugal force. Through a system of gears, a centrifuge bowl is rotated at high speeds. Oil to be purified is allowed to enter the bowl while it is rotating. The heavier components in the oil are thus forced outwards. The solid particles that are too fine to be removed by filtration are forced towards the circumference of the bowl. The oil is also heated so as to reduce the SG of the oil. The difference in SG's between the oil and the water will thus be widening. This will enable a better separation between the oil and the water. Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

The oil purification process 1. The purifier operating process, it is first brought up to operating speed (8000 -9000 rpm), supplied with water fresh water to form the water seal and then oil or fuel to be purified is delivered to the distributor by the inlet pump 2. As the oil or fuel passes down the distributor it is rapidly brought up to the rotational speed of the purifier by the radial vanes provided for this purpose. The oil passes from the distributor through the space between the bottom plate and bowl to the supply holes. Marine Auxiliaries / WAS / Jan 2021

Cont' 3. From the supply holes the oil is fed to the spaces between discs through the distribution holes in the discs. Separation and clarification takes places between the discs, water and sludge moving radially outwards pass along the surface of the discs 4. the purified oil moving radially inwards passes over the upper surface of the discs. Water and sludge are eventually discharge at water discharge port and the purified out and clean oil discharge port. Marine Auxiliaries / WAS / Jan 2021

Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

PURIFIER PARTS AND COMPONENTS Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

CONT’ CROSS SECTIONAL VIEW OF PURIFIER Marine Auxiliaries / WAS / Jan 2021 BOWL Malaysian Institute of Marine Engineering Technology (MIMET)

Stack of purifier disc Marine Auxiliaries / WAS / Jan 2021 Malaysian Institute of Marine Engineering Technology (MIMET)



THE GRAVITY DISC How to choose the correct size of gravity disc ? Marine Auxiliaries / WAS / Jan 2021 Correct size is selected using: •Separation temperature •Density of oil at this temperature •Desired throughput of oil and by using of nomogram from the purifier manual. Malaysian Institute of Marine Engineering Technology (MIMET)

EXAMPLE SHOWING PURIFIER Marine Auxiliaries / WAS / Jan 2021 SYSTEM ARRANGEMENT Malaysian Institute of Marine Engineering Technology (MIMET)

TYPICAL FUEL OIL SYSTEM OF A MAIN ENGINE Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

OPERATING WATER SYSTEM (Desludging system) Example showing bowl in closing position • Sludge discharge is performed as follows. Under centrifugal force acting on pilot valve, packing part is MMarainrieneAuAxuixliialiraierises/ W/ WASAS/ J/aJnan20220121 sealed and operating water is filled in water pressure chamber for closing bowl. Under pressure of the operating water, main cylinder is pushed up to seal main seal ring for purifying operation. • On the other hand, though operating water for closing bowl is constantly supplied to the water pressure chamber for closing bowl, operating water within the water pressure chamber for closing bowl rotates with the bowl, and therefore pressure generated under centrifugal force and head pressure of operating water to be supplied are balanced to cause water level to be stable at a certain position. MMalaalyasyiasinanInIsntsittuittueteofoMf MarainrieneEnEgnignieneereinrigngTeTcehcnhonloolgoyg(yM(MIMIMETE)T)

• Operating water for opening bowl is fed for a certain time to the water pressure chamber for opening bowl. Part thereof passes through, but remaining water is filled in the water pressure chamber for opening bowl. Under pressure of the operating water, pilot valve slides in counter radial direction. • Seal in the packing part is broken and operating water for closing bowl flows out of the bowl. Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

• If operating water for closing bowl passes through, there is no more force pushing up the main cylinder and the main cylinder is pushed down by liquid pressure within the bowl. • Seal in the main seal ring part is broken and sludge is instantly discharged out of the bowl. Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

• On completion of sludge discharge, operating water for closing bowl is delivered to the water pressure chamber for closing bowl. • If operating water is filled therein, main cylinder is pushed up to seal the main seal ring part. At this time the packing part is already sealed Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

MESH FILTER Example showing Mechanical separation of solid contaminants from oil systems (fuel and mesh filter lubricating) is achieved by the use of filters and strainers. A strainer is usually a coarse filter to remove the larger contaminating particles. Both Marine Auxiliaries / WAS / Jan 2021 are arranged as full flow units, usually mounted in pairs (duplex) with one as a standby. The strainer usually employs a mesh screen, an assembly of closely packed metal plates or wire coils which effectively block all but the smallest particles. It is usually fitted on the suction side of a pump and must be cleaned regularly or when the pressure differential across it become unacceptable. Where suction conditions are critical the strainer will be fitted on the discharge side of the pump. Malaysian Institute of Marine Engineering Technology (MIMET)

• When cleaning is undertaken the other unit will be connected into the system by changeover valves or levers and oil circulation will continue. • The particles of dirt collect on the outside of the strainer element or basket and can be removed by compressed air or rushing. • A strainer should be cleaned as soon as it is taken out of the system, then reassembled and left ready for use. . Malaysian Institute of Marine Engineering Technology (MIMET) DUPLEX FILTER Marine Auxiliaries / WAS / Jan 2021

• Magnetic strainers are often used in lubricating oil systems, where a arge permanent magnet collects any ferrous particles which are circulating in the system. • The magnet is surrounded by a cage or basket to simplify cleaning Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

FINE FILTERS Marine Auxiliaries / WAS / Jan 2021 • Fine filters, again in pairs, are used to remove the smallest particles of dirt from oil before the oil enters the finely machined engine parts in either the fuel injection system or the bearings of the rotating machinery. • Fine filters are full-flow units which clean all the oil supplied to the engine. The filtering substance may be a natural or synthetic fibrous woollen felt or paper. • A felt-type fine filter is shown in Figure 8.5. A steel division plate divides the steel pressure vessel into an upper and a lower chamber. • Dirty oil passes into the upper chamber and through the filter element, then the filtered oil passes down the central tube to the lower chamber and out of the unit. Malaysian Institute of Marine Engineering Technology (MIMET)

EXAMPLE OF FILTERS IN BOILER FUEL FINE FILTER AT AUX. ENGINE SYSTEM Marine Auxiliaries / WAS / Jan 2021 Malaysian Institute of Marine Engineering Technology (MIMET)

END OF SLIDES Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

We are all familiar with the use of a rudder, which helps in Marine Auxiliaries / WAS / Jan 2021 turning a ship as and when required. Rudders are the principal system for the entire motion and control of the ships. But we mustn’t forget that the entire rudder action is dependent on another pivotal system called the Steering Gear. Steering Gear integrated with the rudder system defines the complete ‘turning mechanism’ mandatory for each and every ship irrespective of size, type and operation. Malaysian Institute of Marine Engineering Technology (MIMET)

• The direction of the ship is controlled by the steering gear. As the ship moves through the water, the angle of the rudder at the stern determines the direction it will move. • Modern ships are so big that moving the rudder necessitates the use of hydraulics or electrical power. • The steering starts at the Bridge. The required rudder angle is transmitted hydraulically or electrically from the steering wheel at the Bridge to the telemotor at the steering gear, just above the rudder. • As ships continued to grow in size and became faster, modern systems easing human effort were incorporated. Basically, there are two types of commonly used steering gear systems present: a) Hydraulic b) Electro-hydraulic type Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

cont' Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

M a rl ia ny es Ai ua xn iI ln is at ri it eu st /e Wo Af SM /a Jr ai n 2e 0E 2n 1g i n e e

M a lr ai yn So, how does the steering gear se iA works? au nx Ii nl si The total system is made up of 3 parts; ta ir ti ue ts 1. The control system e/ oW fA 2. The power unit MS a/ 3. The power transmission system rJ ia n e2 E0 n2 g1 i n e e

STEERING GEAR SYSTEM TRANSMITTER Control System 1 RECEIVER Power System 2 POWER UNIT STEERING GEAR Power 3 Transmission System Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

M a Bridge steering wheel rl ia ny Remote control es Ai ua Electric motor xn iI ln Pressure is gauge at ri it Valve block ue st Hydraulic oil /e Telemotor Wo replenishing receiver/rudder Af tank indicator SM /a Hydraulic pipe Jr crosshead ai n 2e 0E n2 rudder g1 Hydraulic ram i n e e

Basic operation principle of the steering gear system Basic schematic diagram of steering gear system • The steering gear provides a movement of the rudder in response to a signal from the bridge. The total system may be considered made up of Marine Auxiliaries / WAS / Jan 2021 three parts, control equipment, a power unit and a transmission to rudderstock • The control system consist transmitter and receiver equipment, the equipment conveys a signal of desired rudder angle from the bridge and activates the power unit and transmission system until the desired angle is reached. • The power unit system consist hydraulic pump and hydraulic ram provides the force, when required and with immediate effect, to move the rudder to the desired angle. • The transmission system consist tiller, crosshead and rudder stock linked to rudder, the combination movement of this equipment where is force by power unit will moved the rudder. Malaysian Institute of Marine Engineering Technology (MIMET)

Steering gear failure to turns due to: •Hydraulic power unit leakage •Tele motor transmitter and receiver failure to communicate •Hydraulic pump failure •Hydraulic pipe leakage • Leakage hydraulic oil at hydraulic ram cylinder Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

M a lr Steering Gear Requirement By SOLAS ai yn se iA au For tankers of 10,000 ton gross tonnage and upwards: nx Ii nl Must have two independent steering gear control systems which are operated from the bridge. si Where one fails, changeover to the other must be immediate and achieved from the bridge ta position. ir ti ue The steering gear itself must comprise two independent systems where a failure of one results in ts automatic changeover to the other within 45 seconds.Any of these failure should result in audible e/ and visual alarms on the bridge. oW fA MS a/ 3. The system must be protected from shock loading (due to strong waves) and have pipework rJ which is exclusive / high class / special to it as well as be constructed from approved materials. ia n e2 4. Control of the steering gear must be provided in the steering gear compartment (room). E0 n2 g1 i n e e

M a lr ai yn se iA Main steering gear and rudder stock shall be: au nx Ii • Capable to place the rudder hard over from 35 deg. one side to 30 deg. another side not more than 28 nl second while running with full sea speed and full loaded draught. This should be done at maximum astern si ta speed as also. ir ti The auxiliary steering gear shall be: ue ts e/ • Appropriate strength and capable of steering the ship at navigational speed and could be brought to action oW in an emergency. fA MS • Capable to put rudder from 15 deg. one side to 15 deg. another side not more than 60 second with the ship a/ full loaded condition with speed not less than 7 knot. rJ ia n e2 E0 n2 g1 i n e e

M a rl ia ny cont' es Ai ua xn iI ln is at ri it eu st /e Wo Af SM /a Jr ai n 2e 0E 2n 1g i n e e

M a rl ia ny cont' es Ai ua xn iI ln is at ri it eu st /e Wo Af SM /a Jr ai n 2e 0E 2n 1g i n e e

Malaysian Institute of Marine Engineering Technology (MIMET) Marine Auxiliaries / WAS / Jan 2021

M a rl ia Power units ny es Ai ua xn iI ln is at There are two (2) types of hydraulically powered ri it eu steering gear are in common use, st e/ oW fA 1. The ram type steering gear MS a/ rJ 2. The rotary vane steering gear ia n e2 E0 n2 g1 i n e e

M a lr ai 1. Ram type Steering Gear. yn se iA au nx Ii TWO (2) types in use, depending upon torque requirements, the nl si two-ram and the four-ram. ta ir ti ue 2- Ram steering gear is shown in Figure 12.6. ts e/ The rams acting in hydraulic cylinders operate the tiller by means oW fA of a swivel crosshead carried in a fork of the rams. MS a/ rJ ia A variable delivery pump is mounted on each cylinder and the n e2 E0 slipper ring is linked by rods to the control spindle of the n2 g1 telemotor receiver. i n e e

M a lr ai The variable delivery pump is piped to each yn se cylinder to enable suction or discharge from either. A iA au replenishing tank is mounted nearby and arranged nx Ii nl with non-return suction valves which automatically si ta provide make-up fluid to the pumps. ir ti ue ts A bypass valve is combined with spring-loaded e/ oW shock valves which open in the event of a very heavy fA MS sea forcing the rudder over. a/ rJ ia n In moving over, the pump is actuated and the e2 E0 steering gear will return the rudder to its original n2 g1 position once the heavy sea has passed. i n e e

M a lr ai yn se iA au nx Ii nl si ta ir ti ue ts e/ oW fA MS a/ rJ ia n e2 E0 n2 g1 Figure 12.6(a) Diagrammatic arrangement of two-ram steering gear i (additional items for four-ram system shown dotted) n e e

M a lr ai yn se iA au A spring-loaded return linkage on the tiller will prevent damage to nx Ii the control gear during a shock movement. nl si ta During normal operation one pump will be running. ir ti ue ts If a faster response is required, such as in confined waters/ river / e/ oW cannel / lakes, both pumps may be in use. fA MS a/ rJ The pumps will be in the no-delivery state until a rudder ia movement is required by a signal from the bridge telemotor n e2 transmitter. E0 n2 g1 i n e e

M a lr ai The telemotor receiver cylinder will then move: this yn se iA will result in a movement of the floating lever which au nx will move the floating ring or slipper pad of the pump, Ii nl causing a pumping action. si ta ir ti Fluid will be drawn from one cylinder and pumped ue ts to the other, thus turning the tiller and the rudder. e/ oW fA MS A return linkage or hunting gear mounted on the a/ rJ tiller will reposition the floating lever so that no ia n pumping occurs when the required rudder angle is e2 E0 n2 reached. g1 i n e e

M a rl ia ny es Ai ua xn iI ln is at ri it eu st /e Wo Af SM /a Jr ai n 2e 0E 2n 1g i n e e

M a lr ai yn se iA au Figure 4 Single actuator with two nx Ii power units/piping systems nl The steering gear in Figure 4 si comprises two identical power units, ta ir which fulfil the requirements for main ti steering gear capacity with all power ue units running. Separate power piping ts e/ is provided for each power unit, oW and the piping systems may be fA separated by isolating valves directly MS a/ fitted onto the actuator. rJ Auxiliary steering gear is not required ia because the two identical power units n e2 fulfil the capacity requirements E0 when working together. n2 g1 i n e e

M a lr ai yn se iA 4-ram steering gear is shown in Figure 12.7. The basic principles of operation are similar to au nx the two-ram gear except that the pump will draw from two diagonally opposite cylinders and Ii discharge to the other two. nl si ta The four-ram arrangement provides greater torque and the flexibility of different arrangements ir ti in the event of component failure. ue ts e/ Either pump can be used with all cylinders or with either the two port or two starboard oW cylinders. fA MS a/ Various valves must be open or closed to provide these arrangements. rJ ia n e2 E0 n2 g1 i n e e

M a lr ai yn se iA au xn Ii nl si ta ir ti ue ts e/ oW fA MS a/ rJ ia n e2 E0 n2 g1 i Fig 12.7 four Ram steering gear – actual arrangement. n e e

M a lr ai yn se iA au Figure 1 Main and auxiliary steering gear nx Ii The arrangement in Figure 1 fulfils the nl minimum general requirements for si steering gears. It can be seen that ta ir there is a main and an auxiliary steering ti gear, each fulfilling their respective ue capacity requirements. Failure in ts e/ one steering gear does not render the oW other steering gear inoperative (in this fA MS respect tiller can be excluded). a/ Each steering gear is provided with rJ separate power piping. ia n e2 E0 n2 g1 i n e e

M a rl ia ny es Ai au nx Ii nl Rotary Vane type si ta ir ti ue Steering gear ts e/ Wo fA MS a/ rJ ia n e2 E0 n2 g1 i n e e

M a lr ai yn se • With this type of steering gear a vaned rotor is securely fastened onto the iA rudder stock (Figure 12.9). au nx Ii • The rotor is able to move in a housing which is solidly attached to the ship's structure. nl si ta • Chambers are formed between the vanes on the rotor and the vanes in ir the housing. ti ue ts • These chambers will vary in size as the rotor moves and can be pressurized since sealing strips are fitted on the moving faces. e/ oW fA MS • The chambers either side of the moving vane are connected to separate pipe systems or manifolds. Thus by supplying hydraulic fluid to all the a/ chambers to the left of the moving vane and drawing fluid from all the rJ chambers on the right, the rudder stock can be made to turn anti- ia clockwise. n e2 E0 n2 • Clockwise movement will occur if pressure and suction supplies are reversed. g1 Diagrammatic arrangement of rotary vane steering gear i n e e