An Overview of Common Rail System of Marine Engines

he common rail system, as the name suggest, is a system which is common for every cylinder or unit of the marine engine. Marine engines of the early times had a fuel system, wherein each unit had its own jerk pump and the oil pressure was supplied through the jerk pumps. 

However, in common rail system all the cylinders or units are connected to the rail and the fuel pressure is accumulated in the same. The supplied fuel pressure is thus provided through the rail. A similar type of common rail system is also there for servo oil system for opening of the exhaust valves.

Speaking about the fuel injection system, the common rail system was launched even before the jerk pumps, but was also not successful because of few drawbacks. However, because of some latest advancement in technology and electronics, the common rail system has gained popularity.

The common rail engines are also known as smokeless engines as fuel pressure required for combustion is same for all loads or rpm of the engine.

The common rail is employed in the following system:
1) for heated fuel oil at a pressure of 1000 bars.

2) for servo oil for opening and closing of exhaust valves at a pressure of 200 bars.

3) control oil for opening and closing of valve blocks at a pressure of 200 bars.

4) compressed air for starting main engine.

Main Components of Common Rail System

High pressure pump

The common rail system consists of a high pressure pump which can be cam driven or electrical driven or both. Pressure requirement will be different for different system. For fuel oil the pressure are as high as 1000 bars, for servo and control oil the pressure is about 200 bars. The high pressure pumps are driven by camshaft with three lobe cams. These pumps makes several stroke with the help of three lobe cams and speed increasing speed gear.

For fuel oil and servo oil the pumps are engine driven and for control oil it is motor driven.

Rail unit

A fuel oil rail.

B is the control oil rail.

C servo oil rail.

D Injection control unit(ICU)

E Valve control unit (VCU)

This is provided after the pumps where the accumulated pressure from the pumps is provided to the rail which supplies them to each unit when required. This is located at the engine,s top platform and just below the cylinder cover. These rail units extends to full length of the engine. These are enclosed in the case and have access from the top for maintenance and overhauls.

Valve Block and Electronic control system

This is required for the control of the flow of the fuel oil, servo oil, control oil and starting air from the rail to the cylinder. The valve block is operated by the electronic control which operates when it gets a signal indicating that this cylinder is at top dead centre (TDC) and fuel has to be injected and decides when exhaust valve has to be opened. With the help of electronics the injection can be controlled remotely from the computer. For e.g. if we want to cut off fuel to one of the unit, then we need to cut off the signal given from the control system so that the valve will not open.

The fuel oil system this block is known as ICU( Injection control Unit) and for exhaust valve it is known as VCU (Valve Control Unit). The control system for opening and closing of ICU and VCU is done by electro hydraulic control with which when the signal for open is present the valve for control oil opens and control oil pushes the valve of ICU and VCU to open. The signal for electronic control is given by crank angle sensor which senses about each cylinder and sends signal to system which decides whether to open a valve or close the valve.

The timing of the opening of the valve can also be controlled by the electronics, which means that if the signal is given to open the valve early it will open early and vice versa.

Advantages of Common Rail over Conventional Jerk Pump System

The following are the advantages of the common rail system:

1) Same injection pressure for the engine at all loads or rpm which is not possible in jerk pumps as the later is dependent on the engine speed.

2) Injection timing can be varied during running of the engine, whereas in conventional system the engine has to be stopped and setting for timing has to be changed.

3) The design of common rail is simple as there are no individual fuel pumps and cams for each fuel pump are also removed.

4) The common rail gives smokeless operation whereas in conventional system smokeless operation is only during high rpm.

5) Reduced maintenance is required because of less number of pumps and increased efficient combustion time between overhauls.

6) With this system control of variable opening of exhaust valve can also be done which is not there in traditional system.

Image Credit

Manual of RtFlex engine By Wartsila

Important Points Officer on Watch (OOW) Must Consider While Handling Ship’s Radar

The officer on watch (OOW) on the ship’s bridge should be familiar with the working of all navigational equipment used on the ship. He should also be aware of the procedure for trouble shooting in case any equipment fails.

The radar is one of the most important navigational tools used on the ship. It should be kept running all the time and must undergo periodic tests to check presence of any operational error.

However, there are certain points that the officer on watch (OOW) should be aware of while operating the radar. This would not only ensure smooth running of the radar but also prevent sacrificing ship’s safety.

Points to note while handling ship’s radar:

• The officer on watch should keep a close watch on the ship’s course as sometimes small vessels, objects, and ice may not be detected

• Shadow and blind sectors should also be taken care of while navigating by ship’s radar

• Plotting of targets should be done at longer range

• The officer must use multiple plotting to increase accuracy

• Detection of small targets is better at short range

• The officer on watch should know how to handle video processing techniques

• Long range should be used to get advance notice of approaching vessels, ports, and obstacles

• While deciding the range scale two things should be kept in mind –ship traffic in the region and ship’s speed

• Radar operation should be efficiently practiced in clear weather. This helps the operator to get a better idea about radar observations and target vectors during restricted visibility

• The officer on watch should also consider re-plotting or re-checking when there is a change in ship’s speed or course

• The officer should keep a watch on the variable range market, fixed range lines and electronic bearing lines

• Safe speed of the ship should be decided after using long range to detect approaching vessels and land

• The operating officer must know how to use clutter control to avoid unclear objects

• Heading marker should be properly aligned with the fore and aft of the ship and also with the compass heading

• The parallel index lines should be set correctly

• The officer on watch must check for any gyro error and accuracy of the heading line arrangement

• If a performance monitor is fitted, the quality of the performance must be checked at regular intervals of time

• The officer must check the identity of the fixed object under consideration

• While deciding the closest point of approach (CPA) to avoid collision of the ship, factors such as course, speed, and aspect of the target should be taken into account. Other important aspects of the ship should also be considered to mark the CPA correctly

This is not an exhaustive list, but the above mentioned points should be considered without fail while handling a ship’s radar. Do you know any other important points that should be taken into consideration?

8 Most Expansive Investments by Shipping Industry in Last Five Years

Shipping industry has seen a number of changes in the past few years. With maritime piracy at its all time high, green revolution spreading like wild fire, and new regulations waiting to be implemented, the maritime industry is transforming like never before.

However, go a layer beneath you will find that though a few of these changes have been well planed, most of them are need of the situation. Of these, measures to fight maritime piracy, methods to prevent marine pollution, and steps to reduce carbon footprints are few of the many areas where maximum investments are being seen.

We bring you eight areas of the shipping industry which have seen heavy investments in the last decade.

1.   Anti Piracy Equipment: Piracy at sea, one of the oldest crimes, was not something to fear of until the pirates of Somalia changed the entire scenario with modern speed boats, arms and ammunition, and support of some international terrorist organisations.  Now costing $7 billion to the industry, maritime piracy is the greatest threat to the shipping sector. To tackle this situation, shipping industry must have invested billions of dollars in anti piracy equipment, training, and ships in the last few years.

2.   Private Navy/ Armed Guard Escort: When investment in anti-piracy equipment didn’t bore results, millions of dollars were invested to keep armed guards on board ships.  Of course, anti-piracy equipment, which were not life threatening seemed too small in front of live weapons and ammunitions such as AK 47 rifles, rocket launchers, and grenades.  Ship owners had to ensure their crew’s safety to get their business going, and thus came in the requirement of armed guards and navy escorts. According to a survey, security on board ship costs minimum £8000 for private guards and USD 30000 for navy escorts – yet another huge investment by the shipping industry which is constantly on the rise.

3.   Complying Tier- II and III:  Recent spate of marine pollution incidents has led to tighter regulations regarding pollution at the sea. Pollution from oil spills and harmful emissions from ships have been the main reason for the increase in marine pollution. To control the effects of air pollution from the ship, the industry will now have to comply with Tier II, which puts an upper limit on SOx and NOx emissions coming from marine engine exhaust. This regulation will become more stringent by 2015 when Tier III comes into action. Shipping industry is contributing in its own way to reduce its carbon foot prints. Last few years have seen many new technologies and projects which help in reducing NOx , SOx, and Carbon emissions. Needless to say, massive investment is being considered for research and development of such systems.

4.   Dual /Tri Fuel Engine Intelligent Engines and Scrubber Systems:  In order  to comply with the emission norms at several ports and coast lines, shipping companies are now opting for intelligent and low emission marine engines, which are driven by gas oil, heavy oil and LNG gas acting as dual/tri fuel engine. These engines are highly economical to operate when it comes to complying with MARPOL Annex VI for Air Pollution Prevention from Ships. Also to make sure that the ship engine’s emissions are cleaner, a huge amount of investment is also being seen in cleaning technology such as scrubber systems.

5.   The Craze of Going Green: As the craze of going green spreads like never before, every company wants to make its mark as a “green eco friendly company”. Green shipping is one area which has seen the maximum of investment in R&D, concept design and ship construction, and technologies providing green source of energy. Investments in such projects have seen a constant rise in the past few years.

6.   Ballast Water Treatment: While the Ballast Water Convention waits for implementation, several shipping companies have already started cleaning up their ballast tanks.  Moreover, several countries are imposing strict laws to protect their coastal marine life. This has lead to big investment in manufacturing IMO approved Ballast treatment systems and ballast management systems.

7.   Navigation, Tracking and Locating System: To ensure an accident-free voyage of ships at high seas and also to track ships during distress situation or piracy, ship monitoring and tracking systems are extensively used. With several new regulations from IMO, navigating and operating systems of the ship are getting sophisticated each day. Moreover, investment in Internet and satellite calling and data transferring facilities has seen a sudden rise in the past few years.

8.   Marine Insurance: With increase in global financial recession and sea piracy, the maritime industry has invested much more in insurance premium in the last decade when compared to that invested in early 90’s. Piracy at sea is one of the main reasons for the sudden demand of marine insurance in the last few years.

These are some of the main areas in the shipping industry where heavy investments have been seen.

Do you know any more sectors seeing huge amount of money coming in?

5 Important Energy Recovery Systems Used on Ships

Shipping companies depends on the efficiency with which their operations are carried out at the sea. With increase in fuel and operating costs of vessels, ship owners and operators are trying hard to maintain their profit levels.
Any ship depends on the quality of its crew and machinery onboard. Of all the machines, the main propulsion plant of the ship is of utmost importance as far as the overall efficiency is concerned.

It is a known fact that no machinery is 100% efficient i.e. when we give 100 % input or supply to run machinery, the output is less than that of the input. This is because of the loss of energy (mainly in the form of heat energy) while doing work.

In this article, we will discuss about five main types of waste energy utilisation systems which are fitted on ships and which use the lost energy from the machinery systems to perform other productive work, increasing the overall efficiency of the ship as a whole.

1)      Turbocharger 

Turbocharger is a type of super charging equipment which gives excess fresh air to the engine cylinder during combustion. Turbocharger consists of a blower and a turbine assembly mounted on two ends of a shaft. The hot waste exhaust gases from the engine cylinder are directed on the turbine, which rotates the latter.

The rotation enables the mounted blower to suck excess air from the atmosphere and supply it to combustion chamber via cooler. As the quantity of air is increased, the amount of fuel injection can be increased, which in turn will increase the power.

Read More About latest turbocharger by ABB here

2)      Economiser 

Economiser is a type of boiler which is installed in the exhaust passage of the main engine and where the exhaust heat energy is utilised to generate steam from fresh water.

The exhaust of all cylinders is sent to the turbocharger, where some heat enthalpy is utilized to supply fresh air as discussed above. After passing through turbocharger, the hot exhaust gas with temperature above 300 deg C is passed over stacks of tubes wherein heated water is passed through a forced pump.

3)      Steam Turbine Generator 

Steam generation on ships is done using boilers and economisers which are provided in all ships. Generally the excess steam is dumped in to a dumping condenser, which is technically a waste storage for steam and energy. This excess steam can be utilised to generate energy when supplied to a turbine generator.

The steam is supplied at a pressure to a high speed turbine which is connected to an alternator shaft. The shaft thus rotates and after achieving a rated rpm, electrical power is generated. To understand how turbine generator works read here.

4)      Fresh Water Generator 

As the name suggests, the fresh water generator generates drinking water from sea water. The fresh water generator works on the principle that the boiling point of water can be brought down to reduce the pressure of the atmosphere surrounding it. Maintaining a low pressure, water can be boiled at low temperatures say 50 degree Celsius.

This low temperature is provided by the jacket cooling water of the main engine in which a portion of Jacket Cooling Water (JCW) is diverted to Fresh Water Generator (FWG) to produce fresh water. For complete working of FWG read here

5)      Shaft Generator 

Shaft generator is yet another machinery system where an alternator is connected over the shaft of the main engine. When the main engine is brought to its sea going speed, the shaft generator connected to the main bus bars of the switch board, supplies power to the ship.

This reduces the use of extra fuel in auxiliary generators as they are turned off when the shaft generator is working. To understand the working of shaft generator read here.

Do you know any other important heat recovery system used on ships? We would love to hear about it in comments below.

What is Water Hammer and How to Prevent it?

High temperature steam is used in the engine room for several purposes such as heating fuel line and fuel tanks. Water hammer is a common phenomenon that occurs in steam lines because of water getting stuck in the pipes. Let’s find out how water hammer takes place and what can be done to avoid it.

How Water Hammer takes place?

When the steam lines are shut after use, water gets accumulated in the steam pipes mainly because of condensation of the trapped steam. When high temperature steam is again passed through the lines having water, the steam comes in contact with the water and pushes the water down the line

As the steam comes in contact with water, it eventually condenses and creates a vacuum, which forces the water towards the opened valve at high velocity. The water then hits the valve with high speed, damaging or breaking the valve or piping completely. Valve fracturing because of water hammer has resulted in to disastrous accidents in the past including loss of lives. It is therefore necessary to take every possible step to reduce the effects of water hammer.

How to Prevent Water Hammer?

The most important way to prevent water hammer is to remove the water from the steam lines before passing the steam again through them. Water is removed from the steam lines using drain connections.

All the water should be drained out to make the lines clear. Once this is done, the steam valve should be opened very slightly (cracked open) to heat the line and to bring it to working temperature. This also ensures that the condensate formed due to inlet of steam is removed through the already opened valve. The drain outlet should be continuously checked to ensure that all water is drained out.

Avoid Sharp bends in the steam pipes as sharp bends will help the steam to condense more.

When all the water is removed and the noise from the drain changes to steam blow, the steam valve should be opened further. This process has to be slow and extremely gradual.

After sometime the drain valve should be completely closed and the steam valve to be completely opened. This method prevents water from accumulating in the pipes and eventually stops water hammer.

6 Definitions Every Seafarer Must Know Under the ISM Code

The ISM code was brought into action to inculcate safety culture at the sea and at all levels of seafarers working on ships.

In order to understand ISM, it is important to know definitions of a few important terms which determine the whole structure of IMO’s ISM code.

If you are a seafarers working at the sea, then you must know these six definitions which forms the main structure of the ISM code.

1.       Safety Management System (SMS): The safety management system is a structured and documented system under the International Safety Management (ISM) code which enables shipping companies and its ship’s crew to effectively implement all safety policies regarding ship, crew, and environment while at sea.

2.       Document of Compliance: Document of compliance is a certificate issued to a shipping company which complies with all the requirements of the ISM code.

Document of compliance is one of the most important documents of the ship which are often checked during port state control survey.

3.       Safety Management Certificate (SMC): Safety management certificate (SMC) is a document provided to a ship signifying that the company and its ship personnel operate in accordance with the safety management system (SMS).

SMC should be produced by the ship whenever asked by a PSC.

4.       Objective Evidence: Objective evidence is any form of information, records, or statements of facts which indicates implementation of safe management system by the shipping company and its ships. The objective evidence is based on observations, measurements, or tests that are made during an audit and which can be verified.

5.       Non Conformity and Major Non-Conformity: When objective evidence indicates non fulfilment of a specific requirement stated by the safety management system, a situation of non conformity is considered to have occurred.

A major non-conformity is an extremely serious situation which poses serious threat to the safety of personnel, ship, or the environment. It indicates a major lapse in effective and systematic implementation of the ISM code. Major non conformity would require immediate corrective action to be taken by the ship’s management.

6.       Anniversary Date: Anniversary date can be defined as the day and month of each year which marks the expiry of a relevant certificate or document of the ship under the ISM code.

Pnsc Marine Engineer Apprentice by Zeeshan Ahmed, Marine Engineer

Pnsc Marine Engineer Apprentice 

• 1.  
• 2. IT IS THE ALLAH WHO SUBJECTED THE SEA TO YOU.THAT SHIP MAY SAIL THROUGH IT BY HIS COMMAND ,THAT YE MAY SEEK OF HIS BOUNTY,AND THAT YE MAY BE GRATEFUL (Al-Quran)
• 3. Pakistan National Shipping Corporation Marine Engineer Apprentice
• 4. PNSC WORKSHOP   Pakistan National Shipping Corporation has a marine engineering workshop to provide repair and maintenance services to its own fleet and foreign ships calling at the port of Karachi . Over the last two decades this workshop has gradually achieved international standards in Mechanical and Electrical repairs and steel fabrication works; duly approved by major Classification Societies of the world. The engineering services and expertise are also provided to Pakistan Navy, Karachi Port Trust, Port Qasim Authority and shore based industries. PNSC Workshop over the years has earned reputation for its high quality work offered by its Engineers, supervisory staff, workers. The workshop also provides training  to Marine Engineering and Trade apprentices  for necessary upgradation of their practical skills.  E-mail Address:   [email_address]        
• 5. PNSC M.E.A’s MEA’s sitpend is so much low comparing the apprentice of other organization MEA’s training time must be reduce. From 0830 to 1500 hours. MEA’s instructor arrange so that we learn about the modern practice. It may be our training incharge or any other person hire special for this purpose. MEA’s classes must be arranged and visiting faculty must be arranged to learn modern practice. It may be weekly or monthly.
• 6. PNSC M.E.A’s MEA’s on board cargo ship in group of 10 or 15. and person on ship or from workshop arrange to trained them for ship. Other MEA’s in workshop train of ship part which brought to workshop MEA’s on board on tanker ship in group of 2 or 4 and person on ship or from workshop arrange to trained them for ship. Senior Watchkeeper should tell MEA’s how a good watchkeeping carried out on ship.
• 7. PNSC M.E.A’s When the shops allocation is done. A instructor guide the group how to used the tools correctly and efficiently. At the end a test will carry out that a MEA’s learn the basic shop practice. Then he will transfer to other shop. Ship manual which is available in workshop lend to MEA who is interest one. A visit to industry is carried out. From the headoffice. To update the knowledge of shore industries.
• 8. Instruction to Marine Engineer Apprentices It is mandatory that all marine engineering apprentice maintain there work diaries throughout their prescribed industrial time at a marine engineering workshop. 2. All the entries will be in chronological orders and dates and places of duty must be clearly mentioned. 3. Foremen workshop instructor or the respective shop incharge or the engineering incharge of a ship must countersign the works-statement 4. The work diaries will be issued in a set of one for each engineering apprentice. One of these, when completed and inspection/scruting by the manager workshop will be conducted on quarterly basis 5. The diaries shall be submitted promptly to the officer incharge at the end of every working quarter of the year OIC training will endorse his remarks before the submission to the chief examiner m.o.c 6. Detailed description, lists of tools and gadgets, safety and precaution points and elaborate sketches will bring you much merit points. 7. Signatures of the apprentice and the supervisor must be affixed at the end of the description of the assignment. 8. No intershop transfers shall be made without submission of the work diaries complete in all respects for their respective allotted period. It is mandatory to clear shop test. 9. Unauthorized absence of more then three/week will call for extension/short service certificate. 10. On completion of apprenticeship, the work diary to be returned, if any one found failed to do so, their certificates shall not be is issued.
• 9. Author Introduction ZEESHAN AHMED , Marine Engineer . After doing FSc(pre-engineering) from PAF(fazaia) intermediate college Lahore cantt. I joined Pakistan Marine Academy and choose Marine engineering branch. Two years of training at academy (practical + theoretical) we learned a lot of thing like CNC (computerize numeric code), trained on various models (like control valve, solenoid valve, flow meter, refrigeration system, CPP propeller, Main engine model (TWO stroke), Boiler model (water tube) ……………………………….. in GEK (general engineering knowledge) lab, Mechanical and physics lab, Engineering workshop. ETC . After two years, we joined PNSC workshop for the training of ONE year Industrial training. That was also the golden time where we learnt a lot of things at different shops as well as onboard (repairing and watch keeping). I learn many thing on tanker E.g. MT Johar (learn how to dismantle turbine rotor from casing and what are the precautionary measurement while working on turbine, learn how to change the diaphragm(stationary blade) Plate type heat exchanger gasket change, shell and tube Cooler Anode replacement and (Cont.)
• 10. Introduction (cont.) cleaning of SALT WATER tubes etc.) , MT Swat (major thing which I learn in Swat is how to dismantle head of main unit and copper gasket replacement with a minor facing defect which is found during overhauling which is filled and faced by Belzona) , MT Lahore(About the DEAD MAN ALARM, Alpha lubricator for Cylinder Main Engine Unit, Pump operation and watch keeping), MT Quetta(Auto load sharing of Generator Set, MT Karachi (Dry washing of the main engine turbocharger with granules, water washing of IG Fan of Inert Gas system, sludge removal of from purifier(centrifuge) etc., . One thing I want to added is that the trend in ship building is more toward based on electronic and electrical application. So a marine engineer must strong in automation, instrumentation and control system. PLC (programmable and logic control) and SCADA (supervisory central access and data acquisition) are the upcoming technology that are using on modern ship. The latest engine of MAN B&W is based on Camless technology. Chain is removed ; fuel pump and exhaust valve actuation is control by hydraulic servo(lub) oil which is driven by Axial piston pump mounted on the Fly wheel. Regards, Z.A.
• 11. Author contact information zeetec4@yahoo/gmail/hotmail.com Social networking sites. Facebook: mariner46 Linkdln Orkut Website: zeetec4.googlepages.com Blogs: Any question and suggestion are welcome

Marine engineering pump

Marine engineering pump 

• 1.  
• 2. IT IS THE ALLAH WHO SUBJECTED THE SEA TO YOU.THAT SHIP MAY SAIL THROUGH IT BY HIS COMMAND ,THAT YE MAY SEEK OF HIS BOUNTY,AND THAT YE MAY BE GRATEFUL (Al-Quran)
• 3. Marine Engineering Pumps
• 4. Pumps There are two types of pumps mainly Nonpositive displacement(dynamic) Centrifugal pump Axial pump Positive displacement Rotary Multirotor Single rotor Reciprocating Diaphragm Piston/plunger
• 5. Centrifugal pumps These are nonpositive displacement pump These are categories non-positive because if the discharge is closed; and pump is running no effect on the pump as well as on the pipeline Different cofiguration of these pumps are Vertical Two stages (higher discharge usually) Double suction and single discharge(low disc. Usually) Doubleeeee Horizontal
• 6. Centrifugal pumps Vertical Two stages (higher discharge usually) Two stages give good higher discharge It is used as Fire and General service pump Abbrevation used in ship is F&GS P/P
• 7.  
• 8. Centrifugal pumps Vertical Double suction and single discharge(low disc. Usually low npdh) This pump have good suction and discharge pressure is not so much higher than previous pump This pump is used as Ballast p/p
• 9.  
• 10. Centrifugal pumps Vertical Two stages (higher discharge usually) Two stages give good higher discharge It is used as main sea water pump Abbrevation used in ship is MSW p/p Difference between this pump and the pump in slide #07 is that it is provided with bush instead of bearing.
• 11.  
• 12. Centrifugal pumps Horizontal Two stages (higher discharge usually) Two stages give good higher discharge It is used as boiler circulating pump Abbrevation used in ship is BLR CIRC. P/P The impeller used in this boiler made up of steel because of higher temperature.
• 13. Pump parts Fire and gs pump Parts of pumps body (CI) impeller (brass) 2no. bearing (ball) 1no. center bush (brass) 1no. h-ring (brass) 2no. end bush (brass) 2no. wear rings (brass) 2no. with steel hollow lock pin mostly this pump faces the end bush problem Ballast pump body (CI) wear ring (steel) 2no. o-ring (to separate) 2no. impeller (brass) (double suction single discharge) 1no. main problem is wear ring problem boiler feed pump body (CI)
• 14. Pump parts(contd) wear ring (brass) 2no. center bush ( brass) 1no. h.ring (brass)(with hole for cooling) 2no. gland (brass) 2no. bearing (……….)(ball bearing ) 2no. locking pin (steel)(to place the wear ring at its position) non ZZ if grease nipple is available(otherwise ZZ) main problem non ZZ if grease nipple is available(otherwise ZZ)
• 15. Pump parts(contd) bearing problem (humming sound ) gland packing leakage 3 will damage the bearing if wear ring cut out it will disturb the suction and discharge pressure. During watch we check the following parameter open the particular valve suc and dis for particular pump switch on the motor check the suc and discharge check for any leakage check the movement of fluid by touch hand with discharge pipe.
• 16. MT Quetta MT Quetta Crude oil pump turbine (centrifugal pump) Rpm 1200/1200 Upper bearing 50 Lower bearing 71 LO in 52/55 LO out 44/50 Gland steam 1MPa Exhaust steam 0.04 MPa/0.03 MPa Lub oil 0.12MPa/0.12 MPa Suction 0.01MPa / 0.02MPa Discharge 0.6MPa/0.7MPa Steam Chest 0.7MPa Ballast pump (1S) Suction : -0.1MPa Discharge: 0.25MPa P/P casing: 29 Upperside P/P brg 40 Lowerside P/P brg 46 Bulkhead Stuffing box The difference between mt johar and mt quetta boiler and economizer is that …….. In the johar the economizer getting the feed from the steam accumulator and the quetta getting the feed from the aux. boiler water drum.
• 17. Domestic fridge and Air conditioning Today I am describing about the domestic refrigeration( DOM Fridge ) and as well as air conditioning plant ( A/C acc .)of tanker ship MT Johar . The parts which are I have seen in the refrigeration plant are: Compressor Condenser Thermostatic expansion valve Evaporator And other auxiliary components are Thermostat (operated on principal of expansion/contract : used to set the conditioning temperature) Sight glass Oil separator dryer We can divide the fridge or A/C system into Low pressure High pressure You can seen the block diagram for A/C system. The compressor we used on the board ship may be of y or w type
• 18. Author Introduction ZEESHAN AHMED , Marine Engineer . After doing FSc(pre-engineering) from PAF(fazaia) intermediate college Lahore cantt. I joined Pakistan Marine Academy and choose Marine engineering branch. Two years of training at academy (practical + theoretical) we learned a lot of thing like CNC (computerize numeric code), trained on various models (like control valve, solenoid valve, flow meter, refrigeration system, CPP propeller, Main engine model (TWO stroke), Boiler model (water tube) ……………………………….. in GEK (general engineering knowledge) lab, Mechanical and physics lab, Engineering workshop. ETC . After two years, we joined PNSC workshop for the training of ONE year Industrial training. That was also the golden time where we learnt a lot of things at different shops as well as onboard (repairing and watch keeping). I learn many thing on tanker E.g. MT Johar (learn how to dismantle turbine rotor from casing and what are the precautionary measurement while working on turbine, learn how to change the diaphragm(stationary blade) Plate type heat exchanger gasket change, shell and tube Cooler Anode replacement and (Cont.)
• 19. Introduction (cont.) cleaning of SALT WATER tubes etc.) , MT Swat (major thing which I learn in Swat is how to dismantle head of main unit and copper gasket replacement with a minor facing defect which is found during overhauling which is filled and faced by Belzona) , MT Lahore(About the DEAD MAN ALARM, Alpha lubricator for Cylinder Main Engine Unit, Pump operation and watch keeping), MT Quetta(Auto load sharing of Generator Set, MT Karachi (Dry washing of the main engine turbocharger with granules, water washing of IG Fan of Inert Gas system, sludge removal of from purifier(centrifuge) etc., . One thing I want to added is that the trend in ship building is more toward based on electronic and electrical application. So a marine engineer must strong in automation, instrumentation and control system. PLC (programmable and logic control) and SCADA (supervisory central access and data acquisition) are the upcoming technology that are using on modern ship. The latest engine of MAN B&W is based on Camless technology. Chain is removed ; fuel pump and exhaust valve actuation is control by hydraulic servo(lub) oil which is driven by Axial piston pump mounted on the Fly wheel. Regards, Z.A.
• 20. Author contact information zeetec4@yahoo/gmail/hotmail.com Social networking sites. Facebook: mariner46 Website: zeetec4.googlepages.com Any question and suggestion are welcome