Month: December 2016

Service air compressors on board ship

Service air compressor onboard is used for low pre

FUNCTION AND CONSTRUCTION
Service air compressor onboard is used for low pressure air compression (around 7bar) which is used as general purpose air( cleaning, filter cleaning, operating pneumatic hand tools and pumps, ship air horns)  and also for control air for different pneumatic control systems (blower dampers, E/R control air, air operated quick closing valve system, air for boiler burner etc.). It is the responsibility of fourth engineer to maintain  this to best of its effeciency. Screw compressors are very reliable and only timely maintanance routines such as filter and seperator change are enough to have smooth operation.
In this series we will discuss every aspect of service air compressor starting from general introduction to different case studies regarding malfunctioning of service air compressors on board ships. This series also includes FAQ regarding maintainance and construction of service air compressor.

FUNCTION: 
Air is taken in via suction air filter. The clean air, filtered of dirt and dust, is sucked into screw-end. This air is compressed at screw-end and transferred to oil separator, together with a lot of cooling oil, which has also been injected during the operation. Air and oil are separated within oil tank and oil separator. The separated air goes through minimum pressure valve and is transferred to the after cooler, which cools down the air (Please note that there is no separate oil pump in service air compressor, min pr. v/v holds the air till air pressure rises to a certain value inside the tank, after that it allows air to go through aftercooler. The compressed air inside oil tank provides required pressure to oil.)
The cooled air is then transferred to air reservoir. On the other hand, oil in separator element is transferred to oil filter and then to cooler, pushed by air pressure inside separator and finally reinjected to screw end. Here the oil is cooled by the cut in and cut out of oil/after cooler fan according to the temperature (some models also have thermostatic valve after oil tank which transfer the oil directly to air end if the oil temp is below certain temp e.g. 75°c. if temp is more thermostatic valve sent fraction of oil to oil/after cooler accordingly and finally oil is reinjected to screw end for lubrication and cooling.)
A branch is bled from oil/air tank as control air which is supplied to unloader or air control valve through separate piping.
When unloading inner pressure of oil tank, is exhaust to the atmosphere side of unloader.

DIFFERENT PARTS AND THEIR FUNCTION:
Suction filter– Its purpose is to remove dust from inlet air. It contains dry-type element to remove dust of more than about 10 µ. It is provided with maintenance indicator/ differential pressure indicator for suction filter.
Unloader-  It is mounted on air inlet of screw-end. This unloader functions to reduce load at starting and to regula
te pressure by automatically openingAnd closing inlet port during the operation and limiting the air flow. This is controlled by pressure switch and solenoid valve.

Screw-end (Compressor body)- Screw-end is composed of male rotor with n lobes and female rotor with n+1 sockets. Each rotor is supported by a roller bearing and 2 pieces of tapered roller bearing. As the rotor turns and air is sucked from upper inlet port and is compressed in the space between casing and rotors. Compression continues until the space comes to the outlet port at bottom side and the air is exhausted.

Screw-end (Compressor body)- Screw-end is composed of male rotor with n lobes and female rotor with n+1 sockets. Each rotor is supported bya roller bearing and 2 pieces of tapered roller bearing. As the rotor turns and air is sucked from upper inlet port and is compressed in the space between casing and rotors. Compression continues until the space comes to the outlet port at bottom side and the air is exhausted.

Oil separator element– The oil separator separates oil in the air discharged by screw-end. This machine has a cartridge style separator element. Air flows from the outside to the inside of separator element, and oil is separated. The oil which has been removed collects inside and is eventually reinjected into the screw-end.

Minimum pressure valve– it is mounted at separator outlet. This compressor has no oil pump.
Lubricating oil pressure is so designed as to be held by air pressure inside oil tank.
Accordingly, lubrication must be performed by raising lubricating oil pressure immediately after starting. On that account, minimum pressure valve installed so that air will not be discharged until separator inner pressure is approximately 0.5MPa(5kg/cm2). It  also  functions as check valve since it is closed at unloading and stop.

Oil Filter- it filters particle larger than 5-10 µ in oil. It is of cartridge type.
 
Air and oil cooler/ After cooler-  oil and after cooler are integrated into a single piece cooler made of Aluminum. One side of which acts as a oil cooler and other half as air/after cooler. Cooling air is blown with a fan towards the cooler.
 
Thermostatic valve– In order to prevent condensation of water in oil, oil flow in to oil
cooler is automatically regulated so that lubricant temperature will be kept constant.
In the case temperature is low, as bypass circuit of thermostatic valve is open, oil enter oil filter not going through oil cooler and transferred to screw end. When lubricating oil temperature rises and became 70°C, bypass circuit of thermostatic valve will close down and transferred to screw-end.

 1.  Valve position when lubricant temperature is low.  2. Valve position when lubricant temperature is high

Pressure Switch-Pressure switch is used turn capacity control solenoid valve on and off.

 

Points to be mentioned in a handing over note of a 4/E.

Sample copy of a handing over note for fourth engi

             SAMPLE COPY OF A HANDING OVER NOTE FOR FOURTH ENGINEER.                                                         
                                                        
                                                                          M.T. Vessel Name

                                                       FOURTH ENGINEER HANDING OVER NOTE
 
 PORT- SUEZ                                                                                                                                DATE- 01/11/2016
 

Welcome to M.T.XYZ, flag- S****, IMO no. 9*******, DW- 46791mt,
GRT-29168, built- South Korea, chemical ship type -2, main engine- MAN B&W 6S50MC-C,               

 
 
DURING UMS
If you are on duty, call to bridge at 18:00 hrs and put on UMS mode.
At 2200 to 2300hrs make safety round and inform bridge every 15 minutes during the rounds as no dead man alarm in engine room. At present E/R Kept manned
 
PUMPS
 All pumps working satisfactorily.
All maintenance jobs done according to PMS (PLANNED MAINTENANCE SCHEDULE)
During my contract period following pump overhauled:-

  1. Main cooling sea water pump no 1
  2. Main cooling sea water pump no 2
  3. Sludge pump
  4. Oily Bilge pump

                              
INCINERATOR
Incinerator is working satisfactory. But during burning garbage sluice door is malfunctioning sometime due to air cylinder seal leaking.
Burning of garbage must be recorded to GARBAGE INCINERATOR LOG for Chief Officer’s record in ECR computer. COMMON FOLDER.
Burning of sludge must be done whenever is possible/allowed. All oil transfer and burning activities should be recorded and chief engineer to be informed. Have to maintain the daily ER sounding book.
 
SEWAGE SYSTEM
Sewage and Vacuum system are in good working order.
Recently received spares and all cabin vacuum related problem solved.
Gamazyme 700FN to be added weekly in one of the toilet (STBD/PORT) side to maintain aerobic bacteria in the system..
Both vacuum pumps are in good condition.
Before arrival in port Close SEWAGE OVER BOARD VALVE and put a seal and lock. Seal number must be recorded to ER daily logbook and seal log book including date.
Sewage holding tank to be used during the port and anchorage stays
Note- sewage plant & sewage holding tank should be flushed with sea water at appropriate intervals
  
WATER MAINTENANCE TEST
Water analysis for Boilers and Cooling water should be done regularly. Water proof should be filled up every day to record the analysis. And should generate the final report at every month end. Have all files in ECR computer common folder. Called "water proof" Boiler water p –alkalinity found to be low in both boiler due to heavy exchange of feed water during tank cleaning operation.
.
CHEMICALS
Inventory of chemical is taken at the end of every month. Same report to be given to     2nd engineer for PMS update, any chemical needs must be discussed with the other engineers and requisition to be raised thereafter.
 
BOILERS
Composite boiler water washing for both economizer and fire side last carried out on 13 oct 2016 Boiler swirler, burner, flame eye routine maintenance done 13 oct 2016 Before every port arrival and departure, composite boiler nozzle, flame eye, sight glass and electrodes to be cleanedAuxiliary Boiler now operated in emergency mode
Auxiliary boiler nozzle and swirler cleaned on 28/10/2016. Aux. boiler Chemical dosing pumps is faulty not functioning already ordered new one. Waiting to receive. Careful attention to be paid for the tank level as pump should not run dry.
Blow down should be carried out regularly for both the boilers
 
COMPRESSOR
Both main air compressors running good done all routine as per PMS.
Air filter recently received not of correct size. Same noted to C/E. Topping air compressor working satisfactory sump cleaning and oil change routine done in AUG 2016. Service Air Compressor oil filter, air filter, oil separator, belt, all renewed and oil cooler cleaned (AUG 2016), as per the PMS, working good.
 
FIRE FIGHTING AND LIFE SAVING EQUIPMENT
Fourth engineer is in charge for proper maintenance of fire extinguishers/fire hoses hydrants, foam applicators and EEBD in engine room.
Monthly inspection of fire extinguishers should be done and recorded, any abnormality to be reported to chief officer.
  
SATURDAY ROUTINE
Funnel flaps to be tired out
Engine Room vent fan flaps to be tired out
Emergency air compressor to be tired out. And to maintain emergency air bottle pressure
 
 
                                         
 Incoming 4th engineer                                                                                                 Outgoing 4th engineer                                                                                                                           
                                                   
                                                                                Chief Engineer
                                                
 
                                                               BON VOYAGE AND BEST OF LUCK

FAQ MEO Orals : Safety

Frequently asked questions in MEO Orals of functio

Q. Describe camber, sheer, tumble home, Rise of floor.
Ans.
Camber:-The transverse curvature of the deck from the centerline down to the sides. This camber is used on exposed deck to drive water to the sides of the ship.
Sheer: The curvature of the deck in a fore & aft directions, rising from mid-ship to the maximum at the ends. It makes a ship more seaworthy by raising the deck at the fore & after ends further from the water and by reducing the volume of water coming on the deck.
Tumble Home: In some ships, the mid-ship side shell in the region of the upper deck is curved slightly towards the center line, thus reducing the width of the upper deck & decks above.
Rise of Floor: The bottom shell of ship is sometimes sloped up from the keel to the bilge to facilitate drainage. The rise of floor is very small.

Q. What is freeboard and reserve buoyancy?
Freeboard: It is the distance from the waterline to the top of the deck plating at the side of the deck amidships.
Reserve Buoyancy: It is the potential buoyancy of a ship and depends upon the intact, watertight volume above the waterline.
When a mass is added to the ship, or buoyancy is lost due to bilging, the reserve buoyancy is converted into buoyancy by increasing the draught. If the loss in buoyancy exceeds the reserve buoyancy the vessel will sink.

Q. Why do tankers have less freeboard?
Ans. The value of GM is greater compared to other types of ships, the openings in the tankers are small than of other ship & also the permeability is more.
      
Q. what do u mean by the stability of ship? How does stable Ship returns to the upright position if heeled by an external force?
Ans. STABILITY OF SHIP: The tendency of the ship to come back to its upright position when healed by external force is defined as the stability of the ship.
When a ship is healed, the centre of buoyancy shifts, this forms a righting lever, thus acting in the opposite direction to upright the ship.  

Q.What are tender and stiff ships?
Ans. Tender Ship: The ship with a small Metacentric height has a small righting lever at any angle & will roll easily is said to be a tender ship. In a tender ship, th

e centre of gravity lies below the transverse metacentre.
The GM is more than GZ. & these kind of ship are more stable.
Stiff Ship: The ship with a large Metacentric height has a large righting lever at any angle & has considerable resistance to rolling. A stiff ship is very uncomfortable. In a stiff ship, the Centre o

f Gravity lies above the transverse metacentre.
      

Q. What is the free surface effect? How is knowledge of free surface effect useful?
Ans. Free Surface Effect: When a tank of liquid is partially filled & the mass of liquid is moved. This movement affects the Metacentric height. This is called free surface effect.If free surface effects become more, then ship may capsize.
Q. What is the purpose of Collision bulkhead and what is it's  location?
Ans. Purpose:-
o    Avoid flooding of the ship in case of damage to bows.
Location
   o    The location is such that it is not so much forward as to get damaged on 

impact , Neither it should be too far aft so that compartment flooded forward causes extensive trim by head. As a rule located at a minimum distance to get maximum space for cargo.
   o   Minimum at 1/20 of ships length from forward perpendicular 
   o The collision bulkhead is continuous to uppermost continuous deck
   o    The collision bulkhead is 20% stronger than other bulkheads
   o    Collision bulkhead is 5 to 8 percent of ships length from forward.
 
Q. What are the types of bulkheads?
Ans.
a. Flat Bulkhead
b. Corrugated Bulkhead
c. Longitudinal Bulkhead
d. Transverse Bulkhead.
e. Watertight Bulkheadf. Non-Watertight Bulkhead
g. Fire Class A Bulkhead
h. Fire Class B Bulkhead
i. Fire Class C Bulkhead
j. Collision Bulkhead.
k. insulated bulkhead
 

Q. What are the methods of reducing rolling?
Ans. Various Methods of Reducing Rolling are:-
a. Fin stabiliser
b. Bilge keel

Q. How much length does bilge keel extends to?

Ans. It is half of the length of the ship, starting from mid-ship to fore & aft.
 
 

Q. What is an angle of loll?
Ans.
Angle of LOL: It is the angle at which the ship with initial negative Metacentric height will lie at rest in still water.
If the ship is further inclined to an angle more than angle of loll, the ship will sink.

Q. What is margin line?
Ans. Margin Line: It is the imaginary line which is drawn 75mm below the uppermost continuous deck. It denotes the limit, up to which vessel can be flooded/ loaded without sinking.

Q. What is block coefficient? If we say that block coefficient of one ship is 0.9 and the 0ther 0.95, what does it represent?
Ans. Block Coefficient:-It is the ratio of volume of displacement to the product of the length, breadth & draught.
Cb = Volume of displacement / (L x B x d)
When Block coefficient is more, it means Volume of displacement is more.

Q. What is the regulations for pumping out ER bilges in Special areas and outside special areas?

Ans. Pumping out ER Bilges outside special area:As per Marpol Annex I, Regulation 15.
Any discharge into the sea of oil or oily mixtures from ships of 400 GRT & above shall be prohibited except when all the following conditions are satisfied:-
1. The ship should be proceeding en route from Point A to point B.
2. The oily mixture is processed through an oil filtering equipment.
3. The oily content of the effluent without dilution does not exceed more than 15ppm.
4. The oily mixture does not originate from cargo pump room bilges on oil tankers.
5. The oily mixture, in case of oil tankers, is not mixed with oil cargo residues.
Pumping out ER Bilges inside special area.
1. The ship should be proceeding en route from Point A to Point B.
2. The oily mixture is processed through an Oil filtering Equipment approved by the Administration.
3. The oil content of the effluent without dilution does not exceed more than 15ppm.
4. The oily mixture does not originate from Cargo pump room bilges on oil tankers.
5. The oily mixture in the case of oil tankers, is not mixed with oil cargo residues.
6. Any discharge into the sea of oil or oily mixtures from any ship shall be prohibited in Antarctic area.
Q. Name special areas for MARPOL Annex I.
Ans. As Per MARPOL Annex 1, Regulation 1, the special areas are:-
1. Mediterranean Sea
2. Baltic sea
3. Black sea
4. Red Sea
5. Gulf area
6. Gulf of Aden area
7. Antarctic area.
8. North West European Waters
9. Oman area of the Arabian sea

5 Points all junior engineers must know before going to sea

The Most Important Thing That Will Help You Onboar

1. The Most Important Thing That Will Help You Onboard Is Your Knowledge, Hence  you Must Have Basic Knowledge Of IC Engines, Purifiers, Compressors, Refrigeration Cycle And Plant, Marine Boiler, Steering Gear, Auxilliary Machinery, Pumps, Framo (for Tankers), Basic Automation, Marine Electro Technology.

2. How Can You Acquire The  knowledge?
You Need To Read Books During Your Pre-sea Years, And Remember Just Getting Placements Is Not Enough, If You Are Not Good At Things, You Will Face A Lot Of Problems On Board. Mentioned Here Are The Books You Need Be Thorough With.
For Internal Combustion Engines:
(i)  Reeds 
(ii) D.K Sanyal
(iii) Lambs Question Answers

All Of These Books Are Good, But It Would Be Better If You Stick To One And Read It Thoroughly Before You Switch To Other, So That You Get The Grasp Of The Topics. In Case You Need Any Assistance Regarding Any Topic , Its Always Advised To Look Up To Internet Or Visit Marinelookout And Find Your Answers. 

For Marine Auxiliary Machinery:
(i) HD Mcgeorge.(it Is The Bible For This Subject)
(ii)J.K. Dhar (if You Find Difficulty With Any Topic In McGeorge)

For Marine Boilers: 
(i) GTH FLannagan(best Book Throughout Your Career)
(ii) Milton.

3. Things You Need To Learn Onboard.
Always Keep In Mind While Your Training You Are Onboard To First Learn Then Earn. Some Of The Things You Need To Learn Onboard.
(i) Pipe Line Tracing (eg.  Bilge , Sludge , Fuel Oil Transfer Line, Fuel Oil Service Line, Lub Oil Transfer Line, S.w.cooling Line, Starting Air Line, Fire Line, Bilge & Ballast Line, Ows Line)
(i) Starting And Stopping Of Every Machinery. For E.g Purifier, Compresser, Freshwater Generator, A/E Etc.
(iii) How To Take Bunker And Internal Transfers.
(iv) Sludge/ Bilge  transfer And Shore Discharge Procedores

4.You Should Be Familarised With Recordkeeping,
I) Engine Room Log Book
Ii) Garbage Record Book
Iii) Oil Record Book
Iv) 4/E And 3/E Paper Works

5. You Should Be Well Versed With Terms Like
I) Bunkering 
Ii) Sludge Transfer 
Iii) Bilge Transfer
Iv) Sounding

At Last, Follow Safety Procedures. Keep Your Mind Always Alert And Aware In The Engine Room To Avoid Any Accidents. 

​Mechanical Hydraulic Governor

The mechanical-hydraulic governor controls diesel

Q. Give a brief description for a Mechanical Hydraulic Governor?
Ans: The mechanical-hydraulic governor controls diesel gas or dual fuel engines or steam turbines. The governor is mechanically linked to the fuel racks or to the fuel valves, depending on the system. The maximum travel of the output (terminal) shaft is 42 deg .The recommended travel of the output shall is 28° from no load to full load, which allows sufficient over travel at each end so that the governor can shut down the prime mover and also give maximum fuel when required. Normally, Mechanical Hydraulic Governor operates isochronously (constant speed) regardless of load on the engine. The recommended rated speed range for the governor drive is 1000 to 1500 rpm. The drive power requirement is 249W (1/3 hp) at normal speed and operating temperature. The governor may be driven either clockwise or counterclockwise. Operating temperature range for the governor is -29 to +99 Deg C.
Basic operation is similar for all types. The only difference is in the method of setting the speed. Auxiliary devices provide different functions but do not alter the basic operation of the governor. This schematic shows a basic design and does not include any auxiliary equipment.

Q. Give a detailed Component Description for the Mechanical Hydraulic Governor?
Component Description 
Before getting into the operation, a brief description of the components will facilitate understanding the operation.
Oil Pump
The purpose of the oil pump (14) is to provide oil pressure for the governor. The pump gets its oil from    the self-contained sump (15). The oil pump is a positive displacement gear pump with four check valves   (13) for either direction of rotation. One pump gear is part of the rotating bushing and the other is part   of the laminated drive. The rotating bushing is driven by the governor drive shaft which is driven by the   prime mover. As the bushing rotates, it rotates the laminated drive. The oil pump gears can be driven   either clockwise or counter clockwise. Oil flow is directed through the check valve 

system into the  accumulator system(11).

Accumulator
The purpose of the accumulator (11) is to store oil under pressure for the operation of the UG governor. The accumulator (two cylinders) also acts as a pressure relief valve if oil pressure increases above 827 kpa/120 psi.The accumulator (11) consists of two spring loaded pistons. Oil is pumped into the cylinders and pressure is increased as the accumulator springs are compressed. When the oil pressure exceeds 827 kPa/120 psi ,oil is released back to sump through a relief port(12) in each cylinder. 
Oil flows franc the accumulator through passages to the top of the power piston and to the pilot valve system.
Power Piston

The purpose of the power piston (9) is to rotate the governor output shaft to the increase or decrease fuel position. The power piston is a differential type with oil pressure on both sides of the piston. The top end of the power piston is connected to the governor output shaft (6) through a power lever and link assembly. The bottom of the power piston has a larger area than the top of the piston. Therefore, less oil pressure is needed on the bottom than on the top to maintain the piston stationary. If the oil pressure is the same on both the top and bottom of the piston, the piston moves up to rotate the governor output shall in the increase fuel direction. The piston moves down only when oil under the piston is released to sump. Oil to and from the bottom of the power piston is regulated by the pilot valve system.

Pilot Valve System
The purpose of the pilot valve plunger and bushing is to control the flow of oil to or from the bottom of the power piston. The pilot valve system includes the rotating bushing (38) and the pilot valve plunger (39). The bushing (38) is rotated by the drive shaft (36) .while the pilot valve plunger is held stationary Through this rotation, fiction between the pilot valve and bushing is reduced. The pilot valve plunger has a control land that regulates oil flow through ports in the bushing. When the pilot valve plunger (39) is lowered, high pressure oil flows under the power piston (9), raising it. When the pilot valve plunger is raised, oil is released to yaw from under the power piston (9), lowering it. The higher pressure on top of the power piston(9) forces the piston down When the pilot valve plunger (39) is in its centered position the control land covers the control port as shown in the schematic (Figure 3-1), and there is no movement of the power piston. The movement of the pilot valve plunger (39) is controlled by the ballhead system (23) and the dashpot compensation pistons (34) and (35).

Ball head System
The purpose of the ballhead system (23) is to sense speed changes of the pine mover as compared to the speed setting reference given by the speeder spring(25) and to position the pilot valve plunger (39).The ballhead system includes a ballhead (23), flyweights (24), a speeder spring(25), a thrust bearing (30), a speeder plug (29),and a speed setting rod (21). As the governor drive shaft (36) rotates: the gear on the laminated drive (32) turns and rotates the ballhead gears (23). The flyweights (24) are attached to the ballhead with pivot pins and a thrust bearing (30) rides on the toes of the flyweights (24). The speeder spring (25) is held in position with the thrust bearing (30) by the speeder plug (N).The speeder plug (29) is used to set a pressure on the speeder spring (25).As the ballhead (23) rotates, the flyweights (24) pivot outward due to the centrifugal force. At the same time the speeder spring (25) forces the thrust bearing (30) downward on the flyweight toes. This downward force opposes the centrifugal force of the flyweights. Increasing the drive speed increases the centrifugal force. Compressing the speeder spring (25) with the speeder plug (29) increases the downward force applied to the flyweight toes, and in turn increases the governor speed setting. The prime mover must run faster to generate a centrifugal force greater than the speeder spring force to balance the system again.Speeder spring force or speed setting (25) is controlled manually through the synchronizer (speed setting) adjusting knob (5). It can also be controlled from a remote area if the governor is equipped with a speed setting motor (1).

Compensation System
The purpose of the compensation system is to give stability to the governor and obtain steady state speed control. Also, when correctly adjusted, the compensation system effectively regulates the amount of fuel necessary to bring the engine to the required output to adjust to a decrease or increase in load. The compensation system creates a mall temporary change of speed setting with governor output shaft movement to produce a stabilizing speed droop characteristic in the governor. The change of speed setting is followed by a slow return of speed setting to its original value. Compensation is simply another word for temporary speed droop characteristic. The compensation system includes a large dashpot compensation piston (34), a dashpot compensation piston (35), a floating lever (31), a compensation adjusting lever (22) with a pivotable fulcrum (18), and a needle valve (33), See Figure 3-1. The large dashpot compensation piston (34) is connected to the governor output shalt (6) by a compensation adjusting lever (22). A pivotable fulcrum (18) rides on the compensation adjusting lever (22). Changing the fulcrum's (18) position allows the compensation lever (22) to control the amount of stroke available for the large dashpot compensation piston (34).
The small dashpot compensation piston (35) is connected through. A floating lever (31) to the pilot valve plunger (39) and the speeder-rod (21).Moving the large dashpot compensation piston (34) down forces oil under the small dashpot compensation piston (35). As the small dashpot compensation piston (35) is forced upward, it lifts the pilot valve plunger (39) to close off the control port which stops the flow of oil to the bottom of the power piston (9).The needle valve (33) is a variable orifice which controls the flow of oil between both the large (34) and the small dashpot compensation (35) pistons, and the oil sump.

NOTE: Compensation must be properly adjusted to the particular engine and load to provide stable operation (see Chapter 4, Compensation Adjustments).

Load Limit Control
A load limit control is also a standard feature on the governor. It limits the amount of fuel supplied by restricting the travel of the governor output shaft.An indicator dial shows the governor output shaft limit position. The load limit control may also be used for shutting down the prime mover by turning it to zero.  The purpose of the load limit control is to hydraulically and mechanically limit the load that can be placed on the engine by restricting the travel of the governor output shaft in. the increase fuel direction and consequently the amount of fuel supplied to the engine. The load limit control may also be used for shutting down the engine by turning it to zero.

CAUTION
Do not manually force prime mover linkage to increase fuel without first turning the load limit control knob to maximum position (10). Failure to do so may cause damage and/or failure of governor internal parts.

The load limit control consists of an indicator disc (7) geared to a load limit rack(8). The control knob is also attached to the load Limit cam (16).Load is limited mechanically by positioning the load limit knob (cam 1.6). When the load indicator reaches the preset point, the pilot valve plunger (39) is Lifted, stopping any further increase in fuel Turning the load limit control to zero to shut down the engine turns the cam (16) forcing the load limit (shutdown) lever (20) and shutdown strap (17) clown As the right end of the load limit (shutdown) lever (20) is forced downward, it pivots about its fulcrum and lifts the pilot valve plunger (39), releasing oil from under the power piston (9). Pressure oil acting on top of the power piston (9) forces it downward, rotating the governor output shaft (6) to minimum fuel and causing the prime mover to shut down.

Synchronizer
The synchronizer is the speed adjusting control and is used to change engine speed for a single unit. On engines paralleled with other units it is used to change engine load. The upper knob (called -SYNCHRONIZER- knob on most models or 'SPEED SETTING KNOB' on later models) is the control models. The lower knob ("SYN. INDICATOR') has no function of its own but has an indicator disc which shows the number of revolutions of the synchronizer (speed setting) control knob.

Speed Droop
Speed droop is incorporated in the governor to divide and balance load between units driving the same shaft of paralleled in an electrical system. Speed droop, or simply droop, is one method of creating stability in a governor. Droop is also used to divide and balance load between units driving the same shaft or paralleled in the electrical system. Droop is the decrease in speed that occurs when the governor output shaft moves from the minimum to the maximum fuel position in response to a load increase, expressed as a percentage of rated speed. If instead of a decrease in speed, an increase tales place, the governor shows a negative droop. Negative droop will cause instability in a governor. Too little droop can cause instability in the form of hunting, surging, or difficulty in response to a load change. Too much droop can result in slow governor response in picking up or dropping off a load.
Using au example where the governor speed is 1500 rpm at no load and 1450 rpm at full load.  Droop can be calculated with the formula:

     %Droop =   No load speed — full load speed   x 100   
    full load speed

     %Droop =     1500 rpm – 1450 rpm   x 100 = 3.5%
                                 1450 rpm

E the decrease in speed is greater than 50 rpm when the governor output shaft moves from the minimum to the maximum fuel position, droop greater that 3.5% is shown by the governor. If the decrease in speed is less than 50 rpm droop less than 3.5% is shown by the governor.

NOTE: If the governor output shaft does not use the full 30' of available travel from "NO LOAD' to "FULL LOAD", droop will also be reduced proportionately. Marks on the droop adjustment scale on the dial panel are reference numbers only and do not represent droop percentages. Thus the 100 mark does not represent 100% droop. It represents the maximum droop percentage available on that particular governor model.

Speed droop consists of a control knob, cam and linkage, which when preset, varies the compression of the speeder spring as the output shaft rotates. Increasing the fuel reduces speeder spring compression and, in turn, the governor speed setting. The unit gradually reduces its speed as load is applied. This relationship between load and speed acts as a resistance to load changes when the unit is interconnected with other units either mechanically or electrically.
    Reducing droop to zero allows the unit to change load without changing speed. Normally, set zero droop on units running alone. On interconnected units, set the least amount of droop possible to provide satisfactory load division.For ac generating units tied in with other units, set droop sufficiently high.
To prevent interchange of load between units. If one unit in the system has enough capacity, set its governor on zero droop and it will regulate the frequency of the prime mover system, If its capacity is not exceeded, this unit will handle all load changes. Operate the SYNCHRONIZER knob of the governor with zero droop to adjust the system's frequency. Operate the SYNCHRONIZER knob of the governors that have speed droop to distribute load between units.

Q. Describe the operation of a Mechanical Hydraulic Governor?
Operation of the Governor 
Refer to Figure with the text to better understand the operation of the governor. This schematic diagram is of a basic design and does not include any auxiliary equipment
Changes in governor speed setting produce the same governor movements as do changes in load on the engine. The description that follows is based upon speed changes caused by load changes.

Decrease in Load
When the prime mover is running on speed, the flyweights (24) are in a vertical position for normal steady state operation. The pilot valve plunger (39) is centered over the control port of the rotating bushing, and the control land stops the flow of pressure oil through the bushing (38) control port. There is no movement of the power piston (9), and no movement of the governor output shaft (6),When a decrease in load occurs and the same fuel setting is maintained speed increases. This generates the following sequence of governor movements:
1.As speed increases the centrifugal force of the flyweights (24) increases and becomes stronger than the force of the speeder spring (25).
2.The flyweights (24) tip outward and raise the speeder rod (21) and the tight end of the floating lever (31),
3. This raises the pilot valve plunger (39), opening the control port in the
rotating bushing (38). Oil is released from the bottom of the power piston
(9) to sump.
4. Pressure oil on the top side of the power piston (9) moves it downward,
rotating the governor output shaft in the decrease fuel direction.
5. Linkage from the governor output shalt (6) lowers the compensation adjusting lever (22) which rotates at the fulcrum (18), raising the large dashpot compensation piston (34).
6.Suction is thus applied to the chamber of the small dashpot compensation
piston (35), lowering the left end of the floating lever (31).
7.This lowers the pilot valve plunger (39) closing the control port (37).
8. As sump oil flows through the needle valve (33) from the sump into the
dashpot compensation piston assembly (34 and 35), the small dashpot
compensation piston (35) is returned to its normal centered position by the compensation spring at the same rate as the speeder rod (21). This keeps the pilot valve plunger (39) in its centered position
9. The control port in the rotating bushing (38) is kept closed by the land on
the pilot valve plunger (39).
10. This stops the governor output shalt and power piston movement in the new decreased fuel position. This is the position needed to run the prime mover at the selected speed setting with the new load.

Increase in Load
When an increase in load occurs and the same fuel setting is maintained, speed decreases. This generates the following sequence of governor movements:
1. As speed decreases, the centrifugal force of the flyweights (24) decreases
and the opposing speeder spring (25) force is now greater than the centrifugal force of the flyweights (24).
2. The flyweights (24) tip inward and lower the speeder rod (21) and the right
end of the floating lever (31).
 3. This lowers the pilot valve plunger (39), opening the control port in the
rotating bushing (38). Pressure oil is released through the control port into the lower cylinder of the power piston (9).
 4. The power piston is forced upward by the pressure oil acting on the larger lower surface area of          the power piston rind the governor output shaft is rotated in the increase fuel direction.
5. Linkage from the governor output shaft (6) lifts the compensating adjusting
lever (22), which rotates at the fulcrum(18), lowering the large dashpot compensation piston (34).
 6. Pressure oil is applied to the bottom side of the small dashpot compensation
piston (35), raising the left end of the floating lever (31).
7.This raises the pilot valve plunger (39) closing the control port (37).
8. As pressure oil flows through the needle valve (33) from the dashpot compensation piston     assembly (34 and 35), the small dashpot compensation piston (35) is returned to its normal centered    position by the compensation spring, at the same rate as the speeder rod (21). This keeps the pilot    valve plunger (39) in its centered position.
9. The control port in the rotating bushing (38) is kept closed by the land on the pilot valve plunger (39).
10. This stops the governor output shaft and power piston movement in the new increased fuel position. This is the position needed to run the prime mover at the selected speed setting with the new load.
  
In both cases, a decrease or increase in load, the compensation system operates in opposite     directions. The compensation or amount of movement of the large dashpot compensation piston    (34) is controlled by the compensation adjustment that is, the position of the fulcrum (18).

The rate at which the small dashpot compensation piston (35) is returned to
normal is controlled by the needle valve adjustment, that is, the rate of flow of oil through the needle valve (33).

The Incinerator

The Incinerator is designed according to the basic

INCINERATOR AND ITS USE ONBOARD
The Incinerator is designed according to the basic principles of ensuring a highly efficient combustion and a high degree of safety. It is a MARPOL equipment and is used to burn sludge/ waste oil and garbage onboard. 
The incinerator is designed with a primary combustion chamber for burning W.O oil and solid waste, and a secondary combustion chamber and an after-burning chamber for burning un-combusted exhaust gases.
The combustion chambers are equipped with diesel oil burners, called primary burner and secondary burner respectively.
The inner sluice door is automatically operated.

PRIMARY COMBUSTION CHAMBER
The incinerator is designed to combust solid waste and W.O oil. The heat from the primary burner will start burning the solid waste and the burner flame ignites the W.O oil. The very large heat transmission area in the combustion chamber optimizes the drying and burning of the solid waste.

SECONDARY COMBUSTION CHAMBER
The primary and secondary chamber are separated by a wall made of ceramic heavy duty refractory. In the secondary combustion chamber and after-burning chamber, any gases or particles not completely burned from the primary combustion chamber will be combusted definitively. 

COMPONENTS OF AN INCINERATOR:
1. Charging Door
2. Combustion Chamber
3. Afterburning Chamber
4. Second After burning Chamber     
5. Oil Burner with Built In Pump
6. Ash Cleaning Door
7. Air blower
8. Induced Draught Air Ejector
9. Damper
10. W.O burner
11. Double Wall for Air Cooling

12. Air Inlet nozzle
13. W.O supply tank
14. Mill pump15. Compressed Air
16. W.O Dosing Pump
17. Heating Element

18. Diesel Oil tank
19. Sluice

CONNECTIONS

a. W.O Oil Inlet
b. Steam Inlet
c. Steam Outlet
d. W.O Oil Ventilation Outlet
e. Diesel Oil Inlet
f. Diesel Oil Ventilation Outlet
g. Compressed Air Inlet
h. Electric Power Supply
i. Flue gas outlet
j. Drain W.O tank
k. Drain Diesel oil tank
l. – – –  yard pipe connection

The incinerator is designed to incinerate solid waste and all types of combustible non-explosive oil W.O with a flash point of min. 60°C, without being a nuisance to the surroundings. The incinerator is made as a compact plant of the multi-chamber design.
The incinerator is delivered with the following built-on main components:
– Air blower, supplying air for the induced draught air ejector, cooling air and combustion air.
– W.O burner
– W.O. dosing pump
– Primary D.O. burner for primary combustion chamber
– Secondary D.O. burner for secondary combustion chamber
– Control panel (CP1)
– Thermocouples for detecting primary and secondary combustion chamber temperatures and registering high temperature alarm
– Internal electric-cable, oil, air pipes and valves are factory installed
– Automatic built-on non-fire back sluice
– Supplied loose for installation in funnel:
– Thermocouple for detecting high flue gas temperature and alarm

PREPARATION FOR START-UP OF THE INCINERATOR
Before start-up of the incinerator, the following is to be carried out :
1. Open all inlet and outlet valves for diesel oil.
2. Open all inlet and outlet valves for waste oil and air.
3. Make sure that there are no hindrances for air admission to primary blower as well as
flue gas outlet.

START-UP OF THE INCINERATOR OP PROGRAM 'SOLID WASTE'
1. Make sure that the switch is turned to 'waste oil off'.
2. Activate the main switch on the control panel.
3. Reset the alarm lamps on the push button 'reset alarm'
4. Make sure that all the lamps are alight by pressing the button 'lamp test'
5. For starting of the incinerator, activate the switch for 'incinerator-start'
6. The incinerator will now start automatically by activating the secondary burner in the secondary combustion
chamber.
7. The secondary combustion chamber will have a temperature of 650℃, and the primary burner in the primary
combustion chamber will be activated. The incinerator the operate within set temperatures.
8. If the flame in the incinerator goes out, the incinerator is to be reset by means of "reset flame failure
primary and secondary burner"
9. If add solid waste to the primary combustion chamber using the sluice by activating the pushbutton on the
incinerator wall. 

START-UP OF THE INCINERATOR ON PROGRAM 'W. O'
1. Make sure that switch is turned to 'W.O on'
2. Before start-up of the incinerator, follow the incinerator given under point 'A', item 2 to 7.
When the temperature of the secondary combustion chamber is 650℃ the primary D.O burner in the primary
combustion chamber will be activated. After a preheating period of 25 seconds the W.O burner starts
automatically and operates within the set points.
(Please see the instruction manual).
When the 'delay burner' is switched to automatic 'AUT', the primary D.O burner operates for 25 seconds to
ignite the W.O burner automatically.
When the 'delay burner' is switched to manual 'MAN' the primary D.O burner operates all the time together
with the W.O burner.

ADDING OF SOLID WASTE
Before adding a new charge of solid waste, control whether the incinerator is ready to receive more waste or
not, by looking through the sight glass.

STOPING OF INCINERATOR
1. Activate the switch 'incinerator stop'
2. When the temperature in the incinerator drops to below 100℃, the incinerator stops automatically.
3. When the incinerator has stopped, switch off the main switch on control panel after the blower has been off for 30 minutes.

Maintenance and inspection : Marine Boilers

The boiler maintenance should always be executed w

Q. What are the maintenance to be carried out in boiler?
Ans : Boiler maintenance: The boiler maintenance should always be executed with skill and in accordance with valid rules and regulations from the authorities. Below some recommendations are given for periodical inspections and maintenance.
Daily operation : Daily normal operation of the boiler, some work and check procedures have to be considered every day.
Step A: Check the boiler steam pressure and the water level.
Step B: Check that the feed water control system is operational see separate instructions.
Step C: Check the boiler water condition and inquire necessary countermeasures with regard to the feed and boiler water treatment. If necessary, blow-down the boiler.
Step D: Check the function of the oil burner at different capacities through the inspection holes on the boiler.
Step E:  Check the flue gas temperature after and or the draft loss across the boiler. If either the temperature or the draft loss is too high the smoke tube section, for the oil fired as well as the exhaust gas part, must be cleaned.

Q. What are the weekly checks?
Ans : Weekly routine checks
Step A:  Drain each water level glass for about 10-15 seconds.In case of contaminated boiler water sufficient water treatment the draining of the water level glasses must be done more often.
Step B: Check the safety water level device.
Step C:  Depending on the boiler water tests, blow-down the boiler. Open the blowdown valves quickly for a few seconds, and then close and open for about 5-10 seconds. Repeat this operation when required according to the boiler water tests.
Step D:  Perform scum blow out by means of the scum valve when required. The scum blow out must be carried out until the drained water is clean.

Q. What are the monthly routines?
Ans : Monthly routine checks
Step A:  Test all stand-by pumps.
Step B:  Check all boiler mountings for damage or leaks and repair & replace if necessary. 
Incorrect feed water treatment is commonly causing hard deposits or corrosion. Insufficient blow-down will cause sludge deposits in the tubes and accumulation of sludge in the bottom of the boiler. If hard deposits are not removed.it may lead to overheating in the boiler plate material, which is exposed to the flame in the furnace wall area. This may cause material damages. Incorrect feed water- treatment does not always lead to hard deposits. For example, a too low or too high pH-value may give an electrolytic reaction causing corrosion in the boiler. When the boiler interior is inspected, examine all parts carefully and be attentive to deposits, corrosion, and cracks. It is advisable to pay special attention to this inspection.

Q. What are the procedure and remarks for Boiler inspection?
Ans : Procedure and remarks for Boiler inspection
Step A:  Shut off the boiler and allow it to cool (below 100 deg C).
Note: The boiler should NOT be depressurised by lifting the safety valves and then filled with cold feed water as the stress induced by too rapid cooling may cause damage.
Step B: Empty the boiler and close all valves. If the boiler is connected to a second boiler, check that the valves between them are closed.
Step C:  Unscrew and remove the manhole hatch(es) on the boiler and enter the boiler when it is sufficiently cold. Check the welding in the boiler. A careful examination should be carried out with respect to any possible corrosion or crack formation. Special care should be taken to the water line area in the pressure vessel where oxygen pitting may occur. lf deposits are forming in the boiler tubes, the boiler should be chemically cleaned.it is advisable to consult a company of cleaning specialists rho will examine the boiler deposits and treat the boiler accordingly.
Note: After chemical treatment the boiler should be blown-down at Least twice a day for approximately one week. This will ensure that excessive sludge deposits due to chemical treatment do not collect in the bottom of the pressure vessel.
Contamination If the boiler is contaminated with foreign substances like oil, chemicals corrosion products etc, it is very important to act immediately to avoid damage to the boiler.
Step C:  Check the function of the high steam pressure switch by lowering the set point or by raising the steam pressure, e.g  by closing the main steam valve slowly. The burner must stop automatically.

Inspection of the boiler
A. Inspection of furnace: The furnace should be inspected at least twice a 3 year. During this inspection, the following issues should be taken into consideration: Check for cracks at the refractory    and that the furnace walls are free from excessive soot deposits. Examine carefully the area opposite the burner. Too much soot deposits indicate that the burner should be adjusted. Check that the smoke and stay tubes are intact and that soot deposits are within normal limits.

B. Inspection of exhaust gas section: The exhaust gas section should be inspected at least twice a year. During this inspection, the following issues should be taken into consideration: Check the welding in the exhaust section. A careful examination should be carried out with respect to any possible corrosion or crack formation. Check that the inlet box and outlet box are intact and that soot deposits are within normal limits. Check that the smoke tubes and stay tubes are intact and that soot deposit are within normal limits.

C.Inspection of boiler water side 
The boiler water side (interior) must be carefully inspected at least twice a year. This inspection is of great importance and no doubt the most important of all the maintenance measures. Since it   has a direct influence on the boiler longevity and on the security. At these inspections, hard deposits, corrosion, and circulation disturbances can be found at an early stage, and preventive measures must be taken to avoid unexpected material damage and boiler break down. The presence of hard deposits at the furnace wall and the smoke tubes reduces their heat transfer properties and decreases, the capacity of the boiler. Further, it can be established whether the feed water treatment is satisfactory and whether the blow down is carried out sufficiently.
Layers of thin oil film are exposed to the heating surfaces cause a bad heat transfer in the boiler, leading to overheating followed by burned out pressure parts, In order to remove such contamination a boiling out or acid cleaning are performed immediately.
Note: Corrosion products from the pipe system or insufficient boiler water treatment may result in corrosion in the boiler itself. It is therefore important to observe that such circumstances do not occur in the system.

FAQ MEO Orals : Refrigeration

Refrigeration is a process of moving heat from one

Q. What do you mean by refrigeration? What is the principle of refrigeration?
Ans: Refrigeration is a process of moving heat from one location to another in controlled conditions. The work of heat transport is traditionally driven by mechanical work, but can also be driven by heat, magnetism, electricity, laser, or other means. 
The basic principle of refrigeration is simple. You simply pass a colder liquid continuously around the object that is to be cooled. This will take heat from the object due to the temperature difference.

Q. What is a thermostatic expansion valve?
Ans: A TEV is a regulator through which the refrigerant is metered from the high pressure side to the low pressure side of the system. The pressure drop causes the evaporating temperature (saturation temp.) of the refrigerant to fall below that of the evaporator.
a. Avoids liquid refrigerant return to the compressor suction.
b. Automatic expansion control and maintain 6~7 degree superheat.

Q. What is the function of an L.P controller?
Ans: It stops the compressor at low suction pressure caused by the closure of all compartmental solenoids. When the pressure in the compressors suction rises due solenoid opening, the LP controller restarts the compressor.

Q. What is the function of an L.P cutout?
Ans: To protect the compressor against the low suction pressure due to loss of refrigerant or blockage. If the a/c compressor suction pressure is allowed to fall below atmospheric pressure then there exists a risk of moisture and air ingress into the system.

Q. What is the function of a solenoid valve in the refrigeration system?
Ans: This is an electrical signal actuated v/v in the liquid line of the refrigeration system just before the TEV. This is being actuated by the thermostat in the refer compartment. The solenoid shuts off the refrigerant supply if the compartment is sufficiently cooled to the lower set point of the thermostat. Also it connects the supply when the temperature of the compartment goes high i.e. above the thermostat higher set point.

Q. What is the function of back pressure valve in the refrigeration system?
Ans: Back pressure valve is fitted just at the exit of the refrigerant from the evaporator coil in a multi temperature room system. This being fitted at the exit of the compartments whose temperature is set higher (usually at about4~5 degrees centigrade). The function of the v/v is to maintain equilibrium of the system as the pressure of the gas at the exit of each compartment differs. Moreover, the back pressure v/v creates a back pressure on the evaporator coil and ensures that most of the liquid refrigerant is made available to the lesser temperature requirement compartments as their demand for the refrigerant is higher than the compartments being maintained at a higher temperature. It is spring loaded non return valve.

Q. What is the function of a H.P cut out in a refrigeration system?
Ans: This is a safety device (trip) provided in the discharge of the compressor. It functions to trip the compressor if the pressure in the HP side goes high above the working level.

Q. What is the function of the driers in the refrigeration system?
Ans: The filter/drier is installed in the main liquid line of the system to absorb any moisture present in the refrigerant. It consists of activated alumina or silica gel in a renewable cartridge. It also accommodates the charging connection.

Q. Why is fridge compressor belt driven?
Ans:
a. A slight misalignment is a problem or vibration of the electric motor that may lead to shaft seal leakage, leading to loss of the refrigerant. So, to minimize this, fridge compressor is belt driven
b. In case of the liquid entry into the refrigeration compressor, the belt drive gives a limitation of the damage owing to the slip in the belt and flexibility of the belt material.

Q. What is the quality of the vapor coming back to the compressor suction in the refer system? In addition, how will you ensure that the vapor has adequate degree of superheat?
Ans:
a. The condition of the vapor coming to the compressor suction line should have adequate degree of superheat.
b. The condition is checked by reading the pressure of the returning vapor and its corresponding temperature from the P-T chart provided for the specific refrigerant. This temperature is compared with that of the evaporator outlet and the degree of super heat is expressed as the difference in the temperature.

Q. What are the safeties in the fridge system?
Ans: Safeties in fridge system are:
a. HP cut out
b. Differential lube oil pressure cutout
c. LP cutout
d. Relief valve in the condenser
e. Belt driven
f. Cylinder head relief valve
g. Cooling water low flow/high temperature alarm
h. Motor overload
i. Oil separator
j. Drier
k. Mech. Seal
l. Unloaders /capacity controllers
m. Non return shut off valves
n. Sensors – temperature, pressure

Q. How will you know the presence of air in the refrigeration system? Explain the procedure for purging air.
Ans:
a. High condenser pressure
b. Small bubbles in the sight glass
c. Compressor discharge pressure high/running hot
d. More superheat
e. Pressure fluctuations
f. Inefficient working

PROCEDURE FOR PURGING AIR
a. In the normal operation of the system, measure the liquid refrigerant pressure, temperature at the outlet of the condenser/reservoir.
b. Check the corresponding saturation temperature for the recorded pressure of the liquid refrigerant from the P-T chart for the same refrigerant.
c. Compare the measured temperature with the determined saturation temperature for sub-cooling and adjust the flow of the cooling water through the condenser to achieve near saturation condition inside the condenser,
Then,
d. With the condenser liquid refrigerant outlet valve closed, circulate cooling water, start the compressor and pump down the liquid to the condenser/reservoir, checking the pressure in the suction line. If this pressure is allowed to drop down below the atmospheric pressure then there could be chances of air ingress into the system..
e. Circulate the cooling water till the cooling water outlet and the inlet temperatures equal, a check to ensure complete pump down operation.
f. Check the condenser sea water out let temperature, check the refrigerant pressure corresponding to its temperature from the P-T chart of same refrigerant.

 

FAQ MEO Orals : Air Bottles

Regular inspection to ensure that the internal con

Q. What are the air bottle maintenance and inspections?
Ans: 
a. Regularly drain the bottle of water and oil
b. Regular inspection to ensure that the internal condition of the bottle is good
c. Check for corrosion both externally and internally
d. Inside coating, COPAL varnish condition to be checked to ensure that it is unbroken and no peeling is taking place
e. Welding seem to be checked, carry out dye-penetrant test at suspected areas.
The tell-tale hole between the lap welding seams of the doubler plate / ring to be checked for leaks in service to ensure that the internal welding is intact
g. Face of the man hole to be checked for pitting marks
h. Drain should be clear
i. All points of high stress and corrosion are to be thoroughly checked viz. welds, supports braces, the bottom of the bottle where water/oil is collected. Pay attention to the zone of water line.
j. Check for leaks at the mounted valve glands/flanges, carry out inspection of the valve face and seat for wire drawing effect
k. A timing check with the air bottle completely charged and isolated will give a good idea of the intactness of the pressure vessel
l. The safety/relief valve setting to be inspected as per the class requirement
m. Regularly check the alarms and monitoring equipment for proper functioning

Q. Explain the air bottle entry procedure.
Ans: 
a. Inspection is to be carried out when the receiver capacity is not required for maneuvering
b. Receiver properly isolated, depressurized and notice pasted
c. The internal pressure is to be checked by the pressure gauge and by opening the drain valve
d. Open the manhole door carefully and ventilate the air bottle
e. Obtain an enclosed space permit and comply with it
f. Ventilation is to be maintained during the entire time of enclosed space entry

Q. What action should be taken in case of corrosion/wasting observed on air bottle?
Ans:
MINOR: Clean the site of corrosion, observe the varnish manufacturer instructions for surface finishing prior applying the coat. Apply new coat of the varnish.

MAJOR: The site has to be cleaned and re-varnished as above. The air bottle has to be derated.
In case of excessive the entire bottle has to be replaced.
The derating procedure should be carried out as follows:
a. The extent of the derating is determined by the class surveyor to a value which ensures the safe limit of the hoop stress at this reduced thickness of the shell plating
b. The derating should not violate the starting air requirements for consecutive starts of the main propulsion engine
c. The setting of the safety/relief valve, should be set not exceeding 10% of the maximum working pressure after derating
d. The cut in and cut out pressure switches for compressor automation should be readjusted

For these reasons the air pressure vessels on board ship are fabricated to allow for derating in future still complying with the consecutive start requirements of the propulsion engine.

Emergency Generator Solas requirements, starting and running Procedures

Emergency Generator Is A Source Of Electrical Powe

Emergency Generator Is A Source Of Electrical Power Which Supply Power To All Those Essential Services Required For The Ship's Safety And Navigation In Emergency Condition Like Loss Of Main Power Supply.

Q.1 What Are The Main Requirements Of Solas For Emergency Generator?
I) It Be Driven By Aprime Mover Which Consumes Fuel Having Flash Point Not Less Than 43 Deg C.
II) It Should Start And Connect Automatically To Main Switch Board (MSB) In Case Of Main Power Failure In Not More Than 45 Sec.

Q2. What Checks Is To Be Done Before Starting EG?
Checks Before Starting
A) Check Oil Level In The Engine Crankcase Is Normal.
B) Check Oil Level In The Diesel Oil Tank And Ensure That The Tank Outlet Valve To The Engine Is Open.
C) Check That The Air Supply Flaps Are Open.
D) Check That The Battery Selection Switch Is On 'Battery 1' Or 'Battery 2'.
E) Check The Belt Tension For The Cooling Air Fan.

Q3. Explain The Starting Procedure Of Emergency Generator?
The Emergency Generator Is Always Kept In A Stand By Mode (auto). When A Black Out Takes Place Due To Some Reason And The Stand By Main Generators Could Not Come On Load The Emergency Generator Will Start Automatically At Its Set Time And The Breaker Will Come On And Supply The Emergency Power To The Concern Places.
         The Emergency Generator Are Tried Out Weekly For Their Normal Working Operations It Can Be Started By Two Means One By Battery Start And Other By Hydraulic Start. The Black Out Test Is Carried Once In 3 Months.  
Procedures For Starting Emergency Generator

Starting On Manual Mode
A) Change Over The Manual / Auto Switch To Manual. 
B) Press The 'Start' Button, And The Engine Starts

Starting On Auto
A) Ensure That The Manual / Auto Switch Is On Auto.
B) Turn The Normal / Test Key To Test Position. A Black Out Signal Is Initiated To The Emergency Switch Board.
C) The Emergency Generator Starts And Comes On Load.

Q4. What Should Be Checked During Running Operations Of EG?
Checks During Running
A) Check The Lube Oil Pressure For The Engine Is Normal.
B) Check That The Cylinder Head Temperature Is Within Limits.
C) Check For Any Abnormal Noise / Vibrations At The Engine / Alternator.
D) Check For Fuel / Lube Oil Leaks.
E) Check For Normal Voltage And Frequency.

Q5. How To Stop Emergency G/E & What Are The Post Stopping Checks?
A) Press The Stop Push Button On The Control Panel – The Engine Will Stop.
B) Change Over The Selector Switch Back To AUTO.

After The Generator Has Stopped Check The Battery Condition Check The Specific Gravity, Check The Charging Current Of The Battery Whether It Is Charging At Normal Current, And Check The Water Level. On Board Battery Maintenance Are Carried Out Weekly.

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