Skip to main content

Boiler safety valve setting

  • Take standard pressure gauge (approved by surveyor) for accuracy.  
  •  Fill up water up to ¼ of gauge glass level, and shut main steam stop valve, feed check valve. 
  •  Without compression rings, hoods and easing gears, reassembled the safety valves with  spring compression less than previous setting.  
  • Raise the boiler pressure to desired blow off pressure.  
  • Screw-down spring compression nuts of any lifting valves, until all are quite.  
  • Arrange to have the desired steam pressure  
  • Adjust each valve in turn: 
a. Slacken compression nut until the valve lifts. 
b. Screw-down compression nut sufficiently enough, so that when the valve spindle is
lightly tapped, valve return to its seat and remain seated
c. Measure gap between compression nut and spring casing. 
d. Make a compression ring equal to this gap, and insert under compression nut. 
e. Gag the spindle of this safety valve, to prevent opening, while remaining valve is being
set. 
  • Remaining valve is again set and insert compression ring.  
  • Remove gag and retest both valve to lift and close together.  
  • Cap, cotter and easing gear to be refitted  
  • Caps and cotter pins padlocked to prevent accidentally altering the setting.  
  • When the surveyor satisfied the setting pressure, easing gear should be tested. 
All safety valves set to lift at not greater than 3% above approved working pressure (design
pressure)

Comments

Post a Comment

If you have any doubts.Please let me know

Popular posts from this blog

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
9 comments
Read more

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.
21 comments
Read more

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.
20 comments
Read more