Cylinder Covers

DMI Dubai is a leader in the development of cost effective reconditioning methods for both conventional designs and latest generation of bore cooled cylinder covers in co-operation with OEMs and ship owners.

DMI Dubai's detailed inspection and 'Total Reconditioning System' are designed to bring components back to original dimensions and tolerances to provide a long and trouble free life. DMI Dubai uses the 'Calotte' method to recondition traditional B&W and Sulzer cast steel cylinder covers.

Bore Cooled Cylinder Cover

Modern bore cooled cylinder covers are manufactured from forged steel with cooling bores. Common engine types include MAN B&W, Sulzer & Mitsubishi. Failures during operation can be caused due to various problems, such as:

1. Erosion and corrosion of air starting and safely valves
2. Erosion and cracking in the area adjacent to fuel injector valves
3. Cracking from the cooling bores due to chock-up of cooling water inside the bore
4. Fretting of sealing faces and O-ring grooves.

Modern bore cooled MAN B&W, Sulzer and Mitsubishi covers can be reconditioned in a quick and cost effective manner to improve long term reliability of covers. DMI Dubai’s process involves following steps:

1. A detailed inspection of the cylinder cover, removal of cooling water shield (if required).
2. Removal of the combustion face and cooling water bores. The remaining material is further inspected to ensure that it is free of cracks.
3. Welding of the combustion face, O-ring grooves and landing faces.
4. Stress relieving under precise controlled conditions.
5. Machining to specified dimensions.
6. Re-drill the cooling water bores (if required).
7. Machine spots adjacent to the fuel valve pockets are welded with a special nickel alloy (hard facing).
8. Final machining.
9. Final inspection including a hydraulic test and certification.