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8 Important Points For Inspection and Maintenance of Ship’s Engine Room Crane

TUEsday - 29/08/2017 21:04
8 Important Points For Inspection and Maintenance of Ship’s Engine Room Crane

8 Important Points For Inspection and Maintenance of Ship’s Engine Room Crane

Whether it’s overhauling of main engine/ machinery or shifting of heavy parts, the engine room crane is regularly used for “heavy-duty” jobs, which are usually beyond the physical capabilities of the engine room crew.

Th engine room personnel are qualified to operate the crane in a safe manner but as a machinery, the crane is subjected to breakdowns if proper maintenance and care is not taken. The scenario can be worse if the crane fails in the middle of lifting the load or while carrying out important machinery overhauling.

As a responsible officer on ship, the engineers using the crane must do regular inspection and scheduled maintenance to ensure the crane works safely without giving up at all times.

The engine room crane has a Safe Working Load (SWL) limit, which should never be crossed at all times. The crane manual is the best source to understand when and what inspections or maintenances are required.
Engine room crane
In our previous article on engine room crane, we discussed the safety features provided for operating engine room crane. In this article, we have mentioned eight important points on general maintenance and inspection requirements that must be carried out in an engine room crane:

1. “Not To Forget” Daily Checks: Prior carrying out any operation using engine room crane, a brief check on the following should be done:

    Check the lubrication
    Check the noise level by operating the crane without load
    Check the heat generation
    Check all the limits and trips are working properly
    Check the contact areas of electrical equipment
    Check the brake operation
    Check condition of clamp in the hook

2. Follow Proper Planned Maintenance: The planned maintenance of crane should be followed properly and the following inspections should be done as per the working hours prescribed by the makers:

    Overhauling of motor
    Greasing of wires
    Renewal of wire ropes
    Annual survey
    Load test
3. Ensure Adequate Lubrication: In an engine room crane system, two lubricants are used:

    Grease: Wire ropes, rollers, plain bearings are applied with grease for smooth working. Reduction gear for hoisting and sewing are not applied with grease. Check the greasing of these parts and replenish the grease every 2000 working hrs. or as prescribed by the makers. Ensure not to excessively apply the grease on moving parts as it may cause overheating at the time of rotation, which can have adverse affects.
    Oil: Lube oil is used for lubrication of ball bearing and roller bearing of hoisting and slewing gears. Check the oil level regularly and replenish once the level is below the mark. The condition of oil needs to observed for stain, foam and dust. Renew the oil if the condition is not up to the requirement

4. Check Minimum Requirements Of Wire Ropes: The wire rope of a crane is the main operational part of the system, which is responsible to lift and move the load f-rom one part of the engine room to another part. Following maintenance to be performed on wire rope:

    Wind the wire rope in correct way to prevent kink of the rope
    Lubricate the wire rope at regular interval to reduce internal friction and to prevent corrosion
    Before greasing the rope, clean it with a cloth to remove duct and foreign matter

Requirements for the renewal of wire rope:

    When diameter of rope is reduced by 7%
    When the number of visible wire fracture is 15 over length of 6 times the wire rope diameter
    When the number of visible wire fracture is 30 over length of 60 times the wire rope diameter
    When a kink caused at some part of the rope does not restore to its original shape
    When the rope is reduced in length
    When the rope is twisted out of shape
    When the rope is deemed unusable because of rust or corrosion

5. Inspect The Gears: Gears are used to hoist or slewing the crane to manoeuvre the load at the desired location. Following inspection and maintenance are carried on the gear assembly:

    Drain the gear case oil if the condition is not good and after cleaning the case, replenish it with fresh lube oil
    Keep a check on the gear case noise while the crane is in operation
    Measure the thickness of the gear teeth and if has decreased by 20-25% , renew it with new one
    Inspect the gear for damage of teeths and renew it with new one if the damage is more

6. Check Condition Of Sheave: Sheaves are used to carry the wire ropes f-rom gearing chamber to the hook of the crane. Numbers of sheaves are installed in the assembly for the wire to move smoothly for operation. Following inspection must be carried out:

    Inspect the groove which is in contact with the wire for wear down
    Check all the sheaves for freedom of rotation
    Check the trueness of sheaves. It may bend if the load is lifted obliquely
    Check for cracks and broken circumference on the face of the sheave
    Check the bearings provided in the sheave assembly
    Check the bolt and the pin holding the sheave in place are in good condition
    Check each sheave to insure rope groove is smooth and free f-rom burrs, or other surface defects

7. Carry Out Hook Maintenance: The hook assembly is such made that while the load is ON, it can rotate 360 degree to adjust the position of the load and it comprises of bearings and drums. Following maintenance and checks needs to carried out:

    Lubrication of bearing to be done regularly
    If the partial wear of the part to be suspended with rope is not much worn, use grinder to make it an even surface
    Never repair any crack by welding
    Make sure the dowel pin holding the hook is in position. Measure the pin diameter and replace if its worn out
    Ensure safety latch spring is in working condition to avoid jumping of load
    If rotation lock is provided, check its operation
    Check the material for brittleness, cracking and hardness during annual survey
    If the part used for rigging the rope has worn out, check its shape (concave) and repair or replace as per the condition
    Check throat opening of the hook and if the throat opening exceeds 15% of the original opening, or if the hook is twisted more than 10 degrees, replace the same

8.Check The Brake: The engine room crane is equipped with electromagnetic brake with fail-safe arrangement. This is the most important safety arrangement provided in the crane. Following maintenance and inspection needs to be carried out:

  • Measure the distance between magnet and armature. It should be approx. 0.5mm around the circumference(refer manual for exact value)
  • If the gap is more or less than the recommended value, adjust the braking power nut to reach the required gap
  • If any overhauling is carried out, supply the current tot the magnetic coil only to confirm that running shaft is operating without any resistance
  • The electromagnetic brake is operated by the brake lining. Check for the moisture on the surface of the lining to avoid slippage
  • Check for signs of overheating and mechanical damages
  • Check the tension of spring which carries the brake during overhauling of the brake assembly

The engine room crane is an assembly of various important parts, which need equal attention as any other machinery in the engine room. While the engineers and engine crew are responsible for operating the crane, it is the core responsibility of engineer officers to ensure no breakdown of crane occurs by following correct operating procedures and maintenance schedule.




 

Source: marineinsight

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