Discussion on the management and maintenance exper

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Discussion on the experience of ship management and maintenance

ships will encounter various problems in the process of maintenance. How to solve the problem well and quickly? The author summed up a few small experiences in his work, and wrote them here, which can be regarded as a brick to attract jade, for your reference and discussion

1. Smart displacement saves the hook head lifting steel wire

the small "Le" size makes the hook head steel wire wound on the drum, and often the small steel wire in the outer skin is broken due to friction, but only about 20cm in each circle on the drum will be broken, while other parts will not. In order to save money, when a small number of small steel wires are broken, the whole steel wire can be pulled out, cut 30 cm at the root of the drum, and then fix the steel wire on the drum and wrap it. In this way, the friction part of the steel wire is displaced due to a short length of 30 cm. When rubbing again, the broken small steel wire will not be rubbed, but the steel wire that has not been rubbed. Because the lifting weight of the steel wire has a certain safety factor, it is still within the safety factor when grinding a part of the small steel wire, so it can continue to be used, but it will be replaced when it exceeds the quantity. When the steel wire on the drum is found to be partially broken again 4 Jinan assaying also reduces links and adds 1. The mechanical design is continuous and stable. The root of the steel wire can be cut off for 30 cm again and then fixed and reinstalled. It can still be used for a period of time, and the steel wire can be replaced after the third wear. In this way, one steel wire is almost used as three steel wires, which can undoubtedly save costs

2. Pay attention to the firmness of the current transformer during the inspection of Siemens generator

during the daily inspection, it is found that some of the fixing screws of the current transformer of Siemens generator are loose, and some are not loose, even the same generator. Therefore, it is not ruled out that the screws of the generator installed during shipbuilding have not been tightened. Those that were not tightened at that time have loosened in the later use process, and those that were tightened have no problem. In the CES screw, the nut of the screw (at the upper end and the nut at the lower end) and the fixed iron plate have long-term beneficial conditions for the export of China's extruder industry. There are many friction between the nut and the fixed iron plate. Some nuts grind the fixed iron plate into a 1-2 mm deep pit, and many nuts are also worn away, resulting in the sinking of the current transformer to varying degrees. Therefore, it is recommended to regularly check the fixing screws of Siemens generator current transformer to eliminate potential safety hazards; In addition, when replacing the screw, it is best to smear locking glue on the thread where the nut contacts the screw to prevent the nut from loosening

3. Analysis and suggestions on the causes of the fast failure of incandescent bulbs on board

most incandescent bulbs used on board have a short service life, and some even burn out within a day. There are three main reasons: the first is the poor quality of bulbs, the second is the high voltage of ships, and the third is the severe vibration of ships. Among the three reasons, one is beyond the control of the ship, and the other is inevitable. For the second point, we can lower the ship voltage slightly, because now some 220V lighting voltage has reached 235V or even higher, which speeds up the burning rate of bulbs. In addition, there is another way to use energy-saving lamps (7-watt energy-saving lamps with CCD lamps can be used, and 9-watt lamps are too long to fit). Although the price of energy-saving lamp is higher than that of bulb, its service life is also much longer, with strong vibration resistance and high cost performance. It can also greatly reduce the workload of changing bulbs, so it should be more suitable for ships

4. Heating is the best way to replace bearings and gears

the traditional way to replace bearings is to drive hard with copper rods in cold state, which inevitably causes damage to bearings. A better and easy way is to put the bearing on the cylinder head of the main engine or auxiliary engine for heating 1 hour before installation (it is best to reach about 80 ℃), so that it will be easier to install it on the shaft. Maybe it can be driven by tapping gently. It is better to use an iron pipe slightly larger than the shaft to drive the bearing medium. Although the iron pipe is harder than copper, it is still a soft material compared with bearing steel (the effect of hitting the bearing inner sleeve with an iron pipe is better), while hitting the bearing inner sleeve with a copper rod, the copper rod is easy to slide and hit other parts of the bearing, causing damage. The technical requirement for the disassembly and assembly of the bearings of the small "Le" Kling motor is 110 ℃, while the transmission gear on the motor shaft is required to be disassembled and assembled at 130 ℃. Therefore, heating is the best way to replace bearings and gears

5. Reasons and Countermeasures for the easy burning of Westfalia separator motor

the fuel oil separator used in the small "Le" brand made in Dalian is Westfalia separator, which requires laborious disassembly and maintenance, and has a high failure rate. Due to the small ventilation volume in the oil separator room, the ambient temperature in the oil separator room is high. Ships often sail in tropical areas. At this time, the temperature between oil separators can reach 55~57 degrees Celsius, and the motor must have a temperature rise when it is working. The motor surface temperature can reach 82 degrees Celsius during normal oil separation. In addition, the current during normal oil separation is about 12a, while during slag removal, the pointer of the ammeter is turned to the maximum, reaching more than 27a, and the duration is very long, and then the current drops to about 19A and runs for a period of time, and then it will be reduced to the normal current. Due to the large slag discharge current, the motor temperature will rise higher. The motor can't withstand such a large current and high temperature, so it is burnt out. Solutions: first, increase the air inlet and exhaust volume of the oil separation room; 2、 Open two large ventilation windows on the oil separation room wall to reduce its indoor temperature; 3、 Reduce the time of slag removal and the time interval of slag removal, so as to minimize the working time when the motor is in high current, so as to reduce the risk of burning out when the motor is in slag removal. The time interval of slag removal is 30 minutes, which should also be determined according to the quality of oil, and it is more appropriate to set the time of slag removal at 5 seconds each time

6. Explanation of the asynchronous phenomenon of the parallel lifting crane

relevant instructions for the use of the shoe material heat resistance testing machine when the large "Le" crane made by Guangzhou Shipyard is hoisted together, the phenomenon of asynchronous "high and low lifting" of the boom sometimes occurs, especially at high speed, while it is generally normal at low speed. In this case, the cut-off valve may be stuck. This valve is used to set the oil pressure. When this valve (hook head, boom, etc.) is stuck, the oil mainly returns to the oil tank, and the oil pressure cannot be established or when the oil pressure is low, the control command will not work or the speed will be slow. When the parallel crane works, because the "shut-off valve" of the other crane is normal and the speed is normal, it often shows that the two cranes are not synchronized (mainly refers to the lifting of the crane arm and hook head). If the lifting gear is out of synchronization, it is best to dismantle and check the "shut-off valve" of the slow moving gear to see whether it is normal. In addition, the problem of non operation, slow speed and no high speed may also occur when the single crane operates, which may also be caused by the failure of the "shut-off valve"

7. Suitable current amount of anti marine biological electrode

now some ships have installed anti marine biological electrode, and the current amount set by each wheel is different. Is there a reasonable current amount? Of course, but this is a dynamic quantity, which is related to the size of the electrode and the required replacement interval. Generally, the working current is between 0.65 ~ 1.2A, but now the ship generally docks once every two and a half years, and then the electrode can be replaced. In these 2.5 years, the electrode with current of 1.2A has been consumed long ago, and the electrode with current of 0.65a can be slightly left. Of course, the aluminum electrode used to protect the pipeline consumes faster than the copper electrode. Therefore, the author believes that it is more appropriate to set the current at 0.7A. No matter how large the current is, there will be no electrode material in less than 2.5 years. On the other hand, it is suggested that when customizing the electrode, the size of the electrode should be made slightly thicker or longer if the installation position allows, because sometimes the docking time of the ship will be delayed, which will be more conducive to the protection of the ship

8. Siemens generator bearing high temperature alarm problem

both big "Le" and small "Le" use Siemens generators. Recently, there has been a phenomenon of high temperature alarm of the bearing at the generator drive end. The replacement of the temperature measuring probe is still the same, and the exchange of the front and rear temperature measuring probes is the same, which eliminates the problem of the temperature measuring probe, and the replacement of bearing lubricating oil (generally 68 turbine oil) can not fundamentally eliminate the high temperature phenomenon. So, how to solve this problem? The high temperature is caused by the friction of the lubricating oil during the operation of the shaft. When the generator is running, the movement of the lubricating oil causes the sediment to be stirred up. These sediment not only makes the lubrication effect poor, but also increases the friction, which makes the oil temperature rise. When the temperature rises to the set limit of 80 ℃, it will cause a high temperature alarm. The solution is to replace the turbine oil: one of the methods is to drain the oil immediately when the generator just stops running, so that most of the stirred sediment can be discharged, so as to improve the temperature of the bearing; The second method is to remove the outer cover of the bearing, remove the upper and lower bearing shells, thoroughly clean them with kerosene or diesel oil, clean all sediments, and then replace them with new turbine oil, so that the high temperature phenomenon of the bearing during operation can be completely solved

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