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Q9. With respect to the operation of two stage reciprocating air compressor. Explain:

A. The causes of occasional lifting of 2nd stage relief valve.

B. Breakage of valve plates.

C. Puncture of bursting disc of 1st stage intercooler.

D. Noticeable reduction in capacity of the compressors over a period of time.

Q2.  Describe TWO methods of tracing a superficial crack in a marine machinery component; Explain the procedure for arresting propagation of a crack in a machinery component.

Q3. (a) With the aid of a simple sketch, explain the “trouble spots” in a basic air-conditioning unit and with reference to your sketch, explain the following: -

(a). How the problem of increase in humidity of cooled air is overcome?

(b). How discomfort caused by the excessive drying effect of heated air is overcome?

Q9. Abnormal vibration has been observed in an HFO purifier while in operation. Explain the areas you plan to investigate for rectifying the faults and put back the purifier back to normal operations keeping in view that no reduction in vibration has been noticed even after desludging the purifier couple of times.

Q5. A). Describe the procedure for overhauling a boiler safety valve and explain using sketches where necessary, those parts, which require close attention.

B). Describe the procedure for setting of boiler safety valves.

Q6. A. State the circumstances owing to which it may be necessary to renew a cylinder liner.

B. Explain how the liner is removed

C. Explain how the new liner is fitted; State the important checks to be made before and after fitting.

Q7. Describe with a neat sketch the principle and operation of Biological & Chemical Sewage treatment plant.

(a) What do you meant by B.O.D. What is the significance of B.O.D.

(b) What are the discharge criteria according to MARPOL Regulations?

(c) What routine maintenance is carried out on such Sewage treatment plant?

Q8. Describe the procedure to remove a seized fuel injector body from the cylinder head when it could not be removed by conventional means.

Q9. List the maintenance routines you plan to carry out on the deck hydraulic cranes, winches and mooring machineries before arrival port after a long voyage, considering the fact that cargo operation is solely dependent on the proper Functioning of the crane and winches.