Sunrod boiler inspection and cleaning

1.Open furnace and confirm that the furnace drain pipe is clear.

   Wash furnace tubes and sunrod elements with HPWJ.(high pressure water jet)
   Confirm that water drains from the furnace instantly otherwise
   tubes will be corroded due to sulphuric acid attack.

2.HPWJ is not enough to clean the Sunrod elements.
   Clean sunrod elements gas side from top & bottom by constructing special
    tools.Confirm that the pins of the elements are clean.
   This is not an easy job and have to check many times that the pins
   are clean

3.Open steam drum and all the inspection doors of the water header.

4.Raise the angle bar on the top of the furnace pipe.
Flush with high pressure water one by one all the furnace tubes and confirm that
water is draining to the water header.
Replace angle bar in position confirming that all hinges are intact.

5.Confirm that all the connections of water low level shut down float switch
and water level transmitters are clear and overhaul all the small valves

6.Overhaul all the blowdown valves

7.Inspect condition of refractories inside the furnace and renew as necessary

8.Check furnace air tightness and repair accordingly.

Comments

Differences between MC/MC-C and ME/ME-C engines

The electrohydraulic control mechanisms of the ME engine replace the following components of the conventional MC engine: Chain drive for camshaft Camshaft with fuel cams, exhaust cams and indicator cams Fuel pump actuating gear, including roller guides and reversing mechanism Conventional fuel pressure booster and VIT system Exhaust valve actuating gear and roller guides Engine driven starting air distributor Electronic governor with actuator Regulating shaft Engine side control console Mechanical cylinder lubricators. The Engine Control System of the ME engine comprises: Control units Hydraulic power supply unit Hydraulic cylinder units, including: Electronically controlled fuel injection, and Electronically controlled exhaust valve activation Electronically controlled starting air valves Electronically controlled auxiliary blowers Integrated electronic governor functions Tacho system Electronically controlled Alpha lubricators

Why is a man hole door elliptical in shape?

Any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole is lesser in size than the corresponding circular hole. More over it is prime concern to have a smoothed generous radius at the corners to eliminate stress concentration. Hence other geometrical shapes like rectangle and square are ruled out. To compensate for the loss of material in the shell due to opening, a doubler ring has to be provided around the opening. The thickness of the ring depends on the axis length along the dirrection in which the stresses are maximum and the thickness of the shell. It is important to align the minor axis along the length of the vessel, as the stress in this direction is maximum. Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t= thickness of the shell plating Circumferential stress: Pd/4t More over a considerable material and weight saving is achieved as minor is along the direction of maximum stress.

Shell Expansion Plan

It is a two dimensional drawing of a three dimensional surface of the ship’s hull form. This plan is very useful for the following information:It is used for marking the location of a hull Damage on this plan by identifying the strake number , letter and frame number so that the exact location of the damage and also suggested repairs are marked in a localised copy. The shell expansion can be used for finding areas of painting surfaces such as topside, boot topping and bottom areas by applying Simpsons rules directly. In the shell expansion the vertical scale used is different from the horizontal scale and a suitable adjustment has to be made when calculating areas. This becomes useful in solving disputes concerning areas of preparation and painting. It gives information on the thickness of the original strake which is indicated by the number in the circle shown in the strake. The quality of steel used is also shown by letters A,B,D E and AH, BH,DH, EH.

MEOclassIIexamnotes

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