Skip to main content

Rocking test of crane

The slewing bearing rocking test should be done periodically for the bearing wear tracking and early failure detection.The measurement could be done from the inside and outside of pedestal. Follow the maker's recommendations and conduct the test at the same check points as during the initial test during commissioning in order all subsequent measurements have the same reference 0.

The measurement should be done as follows:

Two checkpoints should be chosen on the pedestal at the circumference close to the revolving side shell of the crane (see the drawing above) normally at the FWD and AFT of pedestal. Some makers recommend to carry out measurements at four points: FWD, AFT, PORT and STBD of pedestal. Measurement points normally marked at the pedestal.

Measurement should be done by depth meter at four directions of boom: FWD, AFT, PORT and STBD. At each boom direction two or four readings must be taken (see item 1 above), check maker's recommendations for details. Record obtained figures on the log sheet. Result of periodic measurement record should be compared with the max. allowable deviation provided by the manufacturer.
Some rocking test procedures require to use a dial gauge instead of depth meter.In this case dial gauge set to 0 after installing at the measurement point and readings taken at four boom positions: FWD, AFT, PORT and STBD. Same procedure repeated for all measurement points as it was done during initial the rocking test.


Comments

  1. I admire this article for the well-researched content and excellent wording. electric chain hoist india. I got so involved in this material that I couldn’t stop reading. I am impressed with your work and skill. Thank you so much.

    ReplyDelete
  2. slewing bearing manufacturer I have read all the comments and suggestions posted by the visitors for this article are very fine,We will wait for your next article so only.Thanks!

    ReplyDelete
  3. Hi, I visited your website and I really like your website, The introduction given by you is very useful,

    ReplyDelete

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

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.