Maintenance of the dredger

Maintenance and Repairing of Cutter Suction Dredger

Cutter suction dredger needs to be maintaining and repairing because of its working environment. Cutter suction dredger is working in water for river channel digging, desilting, sand mining, port building and reclamation. Because of its special working with water and mud, its workload is relatively heavy with open-air operations; after working years by years, will do some damage to dredger parts such as pontoons, machinery, engines, generators; in order to extend the life of the dredger, strengthen maintenance and repair is a must to dredger itself.

 

Dredger maintenance include: dredger pontoons maintenance, dredging machinery maintenance, engines maintenance, electrical system maintenance, hydraulic system maintenance and so on.

 

Dredger pontoons maintenance

The dredger is dismantling type and can be assembly in the working site; it is composed by several pontoons to connect each other with hooks, bolts and nuts. Dredger is in moving condition during work, so all connections should be checked and maintenance in regular; loosen connection should be tightened, fixed, or replaced in order to keep dredger in good working condition.

 

Surface of dredger pontoons are painting layers by layers, it is soaked by wind, sand, and rain, in order to prevent corrosion, every day the surface should be rushed and cleaned, and check the paint in regular. To extend dredger life, dredger pontoons’ surface should be repainted in one year; pontoons underwater should be repainted with corrosion preventive painting in 3 years according to working condition. Dredger minor repair in one year, general repair in three years, bigger repair in five years.

 

Dredging machinery maintenance and repairing

Dredging machinery is included: traversing winch, cutter ladder, cutter ladder winch, cutter head device, traversing winch pulleys, cutter ladder pulleys, spud devices and lifting devices. For these equipment, daily maintenance should be carried out, to inspect machinery lubrication is flexible or not, need oiling lubrication or not, if any machinery is oil leaking or loosened, should be tightened and fixed in time, to prevent any accident in the future.

 

Engines maintenance and repair

The engine is the heart of dredger, the engine does not work, and dredger will stop working, because engine provides power for various mechanical dredging, hydraulic transmission, and electricity. It is particularly important for engine maintenance and repair. We must take it seriously to keep the engine in good working so that to ensure dredger normal operation, and high working efficiency. Technical maintenance of the engine can reduce mechanical failures, and extend the life of the engines.

 

Technical maintenance of the engine is including day maintenance, primary maintenance, secondary maintenance and tertiary maintenance.

 

 

Daily Maintenance

Cleaning the dust and oil around engines, pumps and ancillary equipment, check the joints is loosening or not; if loosening, tighten bolts in time.

 

Check engine oil condition, oil quantity and oil quality inside oil shell, if oil suddenly reduced or increased is found, and there are metal shavings or other variation inside, the oil should be replaced with new oil.

 

Check and correct the valve clearance.

Check conditions of the electrical equipment, oil cleaning, water stains cleaning, dust cleaning, and joints fastening.

Check tightness conditions of all connections.

 

Check oil stock conditions of different oil supply system, connection of various components in order to refueling tighten connection in time.

Check conditions of cooling system: cooling pump is working or not, cooling water tank is adequate or not, cooling water is added in time or not.

 

Contents for primary maintenance after dredger working 100-150 hours

Daily maintenance work

Check crankshaft and other driven equipment is moved off-center or not, if moved, then corrected.

Check bolt connection and snap rings are loosened or not, if loosened, tighten them in time.

Cleaning oil tanks and oil filters, remove dirt from tanks and filters.

Checks rotate working parts of engines, filling lub. oil to all running parts.

Cleaning oil bottom parts, cleaning engine oil filter, after filtering engine oil, add new one.

Cleaning the air filter

Check the cooling system, and water pump bearings, and add butter to the place where should be.

 

Secondary Technical Maintenance after dredger running 300-400 hours

Second technical maintenance is based on primary maintenance is finished

Check the fuel system, cleaning the diesel tank, filters, oil pipelines, fuel pump and oil injectors, etc.

Checking spares on crank rod connection structure, gas system, cooling system, rotate adjust structure, if any is loosened, repairing and tightening on time.

Check cleaning lubrication system, crank tank, engine oil pipe, oil pump, and cooler. Change engine oil accordingly.

Washing cylinder covers, removing coke, grinding valves, cleaning exhaust pipe.

Check generator and start motor is normal or not, testing and maintaining accordingly.

 

Tertiary maintenance after dredger working 700-1000 hours

Tertiary maintenance is based on secondary maintenance is finished.

Cleaning and checking structures of main equipment parts, checking conditions of cylinders, pistons, piston rings, piston pins, as well as the mechanical linkage bearings, etc. in order to repair or replace damaged

parts in time and meet the technical requirements of the design, make engines work normally.

 

Maintenance and repairing of electrical systems

Electrical systems are including generators, motors, power distribution boxes, console panels in operating room, electric valves, batteries and so on.

 

For electrical equipment, it should be kept in clean, no dust, no oil, no water mark, check damaged and loosened joints in time to avoid short circuit and burn, so that can prevent any accidents.

 

Check belt tension by hand pressure, take bending to bottom at the center of belt by a distance of 10-15mm. Doing dust-protection work accordingly.

 

Check temperature of generator, if temperature is too high to stop for checking.

 

Check conditions of bearing lubrication, add new lubrication if needed.

 

After every 300 --- 400 hours working, open dust cover to remove dust and oil dirty.

 

Avoid putting generator in the moisture environment.

 

Check connections of regulator; interceptor; and wire rope in regular; if any problems among them identified, then maintenance in time.

 

Checking battery voltage, and charging condition in regular.

 

For electricity panel in operating room, need to keep it clean and no wire rope exposed, in order to prevent disconnection and short-circuiting. In daily operating, check wire rope is loosen, with barbed or not in regular is requirement to operator.

 

Fifth, hydraulic motor maintenance and repairing on dredger.

Hydraulic motor is the mayor machinery in the dredging process, should do a good job on maintaining.

 

Keep machines on dredger are clean, no loosing, and no oil is spilt.

Observe operating conditions of the motor, if there is any difference with normal working.

 

Head of oil spill tube up must be parallel to the surface of motor oil, It is does not be higher than the oil, nor less than the crankshaft end. Otherwise it will cause increased wear oil-free cavity, the cavity pressure above the oil level will rise prone top cylinder phenomenon, the link derailment accident. crankshaft.

 

Procedure for dredger testing in the shipyard launching site

Before 2 weeks of dredger testing, we will inform customers to our shipard for dredger testing; if customer cannot come, videos and pictures will be sent to them for references.

 

Preparing work before testing

After dredger assembly finished, cleaning the dredger deck and pontoons, if any parts are broken or painting are damaged, repairing and repainting before testing.

 

Moor dredger in a safe place before testing.

 

Check all conditions of machinery installation and connection. If any parts are install not reasonable; any connection parts are loosened and any parts are missed for installation.

 

Get all oil and cooling water ready and put into machines for testing.

 

Testing contents

Check working condition of electricity when all machines are working.

 

Using of the emergency pump to check conditions of hydraulic system operation, other systems, and mechanical dredging work.

 

After system working condition checked, will check engines running and power capacity.

 

After engine testing finished, dredging pump will be tested and rotates at different speed with clean water.

 

Upon testing completion of electricity system, hydraulic system, engines, and dredging pump, main pump hydraulic pump will be opened and hydraulic system load performance is tested to check operation of the work of the various hydraulic machinery and systems.

 

After testing

After testing finished, all equipment performances and testing recorded will be printed as report.

 

After all report finished, send to customer as review.

 

After testing, do a good job on dredger and workers safety.

 

After testing, all work about dredger dismantle should be prepared and let customer knows when and what time will do delivery.