Oral General

September 14, 2017 | Author: Prakhyati Raut | Category: Pump, Gas Compressor, Valve, Boiler, Refrigeration
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Oral General...


FUNCTION 1: MARINE ENGINEERING-GENERAL 1. Why is Boiler water treatment required? A) For efficient operation, minimum overhaul.Increase life of boiler and maintain quality of water. Reduce oxygen and carbon dioxide content. Reduce scale formation. Efficient heat transfer. Maintain alkalinity of water,counter effects of oil and sea water ingress. 2. What is the allowed chloride content? 3. Why is the boiler water circulating pump required for EGB? 4. How does a Bourdon pressure gauge work'? A) Elliptical pressure transducer, bourdon tube, open @ one end to pressure liquid. Other end closed, connected to a sector and pinion connected to the pointer which moves on a calibrated scale. Due to applied pressure the bourdon tube tends to become circular, which moves the free end and thus moves the pointer. 5. How do you blow through a boiler gauge glass? 6. Why is a hail given in the gauge glass? A)to protect the guage glass from accidental damage. 7. How do you tighten a gauge glass after assembly? Inward to outward moving in opposite steps.8. What is a setting of a boiler safety valve'? 9. What is the normally allowed chloride content in a water tube boiler? 10. How do you blow down a boiler and inspect it? A) C/O from HO to DO. Stop firing when on DO. Slowly blowdown in stages. Pr 5-7 Bar shut all steam valves. When pr 1 bar open vent to prevent vacuum formation. When Loaded or Draught high, drain remaining water into separate holding tank. Pr guage should show 0. Proceed for opening up. Open top manhole door with chain blocks. Slacken door n break joint make sure no pr inside. Remove door. Open bottom inspection door. Venting to be done. Enclosed space entry. 11. Why is pre purging necessary before firing boilers? A)Avoid blow back or back fire. 12. How does flame failure alarm come? A)flame eye consists of a photo electric cell which converts ir radiations into electric signal. Electron flow in the electric circuit can be measured and detected as a proof of flame. 13. Type of boiler burner on last ship. 14. What is the voltage used for the ignitor? 15. How will you know EGB is leaking?

A) When engine running, white smoke from funnel. When engine stopped, water accumulates in bottom of EGB. Sealing pots will overflow. Cascade tank low level alarm. 16. How will you stop the leak? A) Stop engine, or by pass EGB. Stop main steam stop valve. Run circulating pump for an hour. Stop circulating pump. Close inlet and outlet valve of EGB. Cut plates of the EGB casing. Find out leaky tube. Put plugs. 17. What is the purpose of soot blowing? A)Remove soot deposits from surface of EGB,efficient heat transfer, avoid melting of tubes, avoid uptake fire. 18. When do you start the circulating pump? A) Usually kept running, if shut to be started 1 hr before engine starts. 19. What is the temperature of steam in the boiler? 20. What is meant by superheated steam? 21. How is a boiler safety valve set? 22. What is the setting? 23. What is the meaning of accumulation pressure test? 24. How do you blow down a boiler and inspect? 25. How do you repair leaks? 26. How do you blow through gauge glasses? 27. What is the safety mechanism in case the glass breaks? 28. Which part of the ship's boiler has a higher safety valve setting? EGB or auxiliary 29. When is the pressure testing of boilers done? How is it done? 30. Why is Fridge compressor belt driven? 31. What is meant by 1 ton of refrigeration? Amount of heat removed by melting one ton of ice in 24 hrs. 32. Is there any difference in lubricating oil pressure reading of fridge compressors when compared to air compressors? 33. How do you read the lubricating oil pressure of fridge compressors?

A) Pressure gauge reading – suction pressure = L O pressure. 34. Some times the pressure gauges used in fridge systems also have temperature readings. What is the use of this? A)Compound pressure gauge gives pressure and corresponding saturation temperature. 35. How is the temperature of cold room maintained? 36. What is the role of the TEV? A)Regulate the flow of refrigerant in the refrigerant according to demand and maintain a constant degree of superheat. 37. What is mean effective pressure of diesel engine? A) Theoretical const pressure which can be assumed to be acting on the piston during the power stroke. Area of indicator diagram/length of dia. 38. What the cooling water treatment? A) Non nitrite. Nitrite borate. 39. What tests are done on L.O.? 40. What is the correct procedure for L.O. sample collection? After the filters when the engine is still running. 41. What are the COPT trips? 42. How will you test the working of a compressor safety valve? 43. Why is bursting disc provided in air compressor'? A) To avoid over pressure in casing due to tube leaks. 44. What is a lantern ring? A) Perforated hollow ring situated @ centre of stuffing box or gland packing. Cooling sealing and lubrication. 45. If a bursting disk ruptures, what will be your action? A) Stop Compressor immediately. Trouble shoot n overhaul. 46. What is a lantern ring? 47. If the inter-stage relief valve is lifting,what could be the reason? A) Intercooler tube leakage, HP suction valve leaking 48. Why is multistage compression used? A) Compression cycle as close as possible to Isothermal.

49. Why is deck seal used in IG systems? A) Prevent back flow of hydrocarbon gases into the engine room. 50. What is the allowed C02 content in IG? A) How is it controlled? Max 8%, Alarm @ 5%.Controlling air fuel ratio of the boiler. 51. Difference between purifier and clarifier? A) Purifier separates two liquids, clarifier separates solids and liquids. Gravity disc. Clarifier disc stack has no interphase holes. 52. What is the separation principle used in purifiers? A) Difference in density of oil and water. Means of separation by centrifugal force. 53. Types of fuel used on board ships A) flash point not less than 60 deg C. For Emg Gen.Not less than 43 deg C. HFO, DO, MGO, HSD. 54. Effects of contaminants in fuel oil. 55. Safety devices in setting tanks A) flame trap on vent, weighted cock on sounding pipe, overflow line with sight glass, high and low level alarms, spring loaded drain valves,Quick Closing Valve on Pump Suction. 56.What is a self-cleaning purifier? A)Solenoid valve on water outlet line. Water transducer in oil outlet line. Continuous feeding of oil and separated water and sludge collected inside bowl. Shifting of interphase towards oil side. When water detected by transducer,it opens the solenoid valve or closes sealing water for desludging. 57. State the safety features on an Air compressor? A)Busting disc/ relief valve. Relief valve on LP and HP side. Unloader, Motor High Current protection. High Air temp alarm and trip, LO low press alarm and trip. 58. What is the purpose of a bursting disc? 59. Causes, signs and action to he taken in case air starting line explodes? 60. Before starting an air compressor what is checked'? A)lube oil level in sump. JCW in/out v/v open. Cyl lub tk level. Compressor discharge valve fully open. If starting after overhauls then check direction of rotation. 61. State function of H.P. & L.P. Valves fitted on an air compressor? What types are these? 62. Why is a jacket necessary in air compressors? A)Cooling. Avoid burning of lube oil.Efficient lubrication and compression.

63. What is difference between isothermal and adiabatic compression? A)Isothermal constant temp, adiabatic- constant heat. 64. How to start an air compressor? What problems can he encountered? 65. What is the safety provide on an Intercoder? Bursting Disc/ Relief Valve. 66. Bumping clearance of air compressor? 67. What are different types of refrigerants used on ship? CFC 11, CFC 12, HCFC 22/ F22, HFC 123, HFC 134A 68. State the properties of F-12 gas. 69. Cause of frequent cut in- cut off at Refg. Plant Compressor. Causes/Effects and remedial actions to be taken. 70. What are the parameter you will check in a refrigeration compressor? 71. What will be the condition of a suction line hot or cold, Why'? 72. If there is frosting in suction line of compressor, what could be the causes'? 73. How different temperatures are maintained in different compartment of a refrigeration system? 74. What is back pressure valve and where is it used? Slow and controlled cooling by increasing pressure and reducing rate of evaporation. 75. What is a compound pressure gauge'? 76. What are the major components of a refrigeration plant? Compressor, hp cut out, condenser, receiver, oil separator, drier, solenoid valve, tev, evaporator, lp cut out, defrosting line. 77. Sketch Hydraulic steering gear system. What is the material of Ram'? 78. Why do we start second steering pump while manoeuvring? 79. How much time is taken for rudder to travel hard port to hard stbd with one pump/two pumps? 80. What do you mean by balanced rudder’?

81. What do you mean by semi-balanced rudder? 82. What do you mean by unbalanced rudder? 83. What should be area of the rudder’? 84. How does emergency steering work? 85. What safeties are provided on windlass machinery? 86. State the steering gear provided on your last ship. 87. Types of steering gear. Electric, electro-hydraulic, hydraulic 88. What is the purpose of a hunting gear? What is the purpose of Rudder Carrier Bearings? Takes weight of the rudder on grease lubricated thrust face. 89. State the principles of winches. 90. In a centrifugal pump, why wi1l starting torque he less when starting with discharge valve shut? Discharge of pump is minimum, discharge head maximum, power consumed minimum, thus torque minimum. 91 Why there are wear rings in a centrifugal pump? 92. Why is gear pump used for pumping oil? Positive displacement pumps. 93. How will you start a centrifugal pump? 94. Why relief valve is fitted on discharge side of a positive displacement pump? 95. Types of pumps positive displacement, rotodynamic. 96. Advantages and disadvantages of various pumps. 97. Sketch a Bilge system. 98. How is fresh water generated on board? What is reverse Osmosis’? 99. State the types of valves in Bilge Pump. What is the material of Bilge Piping? What is the safety feature provided on a Bilge Pump? 100. How will you test emergency Bilge suction?

101 What is the difference between an ordinary cooler and inter-cooler provided in a compressor’? 102. What material is used for stern pipes? 103. What types of valves are there in the Bilge and do you box them up? 104. What are the materials used in shipping industry? 105. What are the components in a valve? Valve body, bonnet, gland cover, gland, handwheel, spindle, valve, valve seat. 106. Safeties provided on Condensers? 107. Boiler blow down method. 108. What is hot well, If oil comes into hot well What action will you take and how to trace the leak? 109. Preparation for boiler survey. 110. Reasons for lifting relief v/v in air compressor. 111. How sludge effects overflow in purifier. 112.Adjustment of safety valve. Lifting press of safetyValve. 113.Types of T/C. radial flow, axial flow. Pulse type, constant pressure type. 114.Blanking of boiler tubes. 115. How to create vacuum in F. W. G.? 116. Type of condenser used in F. W. G.? surface contact 117.How many type of condenser? direct contact type and surface contact type. 118.How much salinity of F. W. G.?2-3 ppm 119.Type of steam used in COP? Superheated steam @ 14kg. 120.What is superheated steam and how to obtain it? 121. Boiler type on board.

122. In your ref. System, Freon is low pressure, what does it indicate? 123.What is short cycling in ref. System? 124. Construction of L.O. Cooler? 125. Boiler gauge glass on both sides, why not on single side ? Regulation 32.6 Solas. Two independent means of indicating its water level at least one of which shall be a direct reading gauge. 126.Charging of refrigerant. Charging line and valve after receiver outlet valve on the drier. Close receiver outlet valve. Pump down all refrigerant into the receiver. Purge air from receiver into recovery bottle. Connect refrigerant bottle to charging line. Run compressor, till level is ok. 127.Air Bottle not filling reasons. 128.Transducer [In purifier] water sensor in purified oil line 129.Relief v/v on which pumps to be provided? Positive disp pumps. 130. Air bottle, safeties. 131. Propeller drop? 132. Pump vibration, reasons. Misalignment between motor and pump shaft, impeller wear down, bearing broken, foundation bolts loose, foreign material inside casing, cavitation of impeller. 133.Air compressor motor amperage is hunting, what action to be taken? Unloader filter chocked. Liner leaking, suction filter chocked. 134.Boiler gauge glass (remote circuit)

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