Failure And Maintenance Of Ship Hydraulic System

1. Fault type

The frequent failures of marine hydraulic equipment include: action failure; pressure failure; noise and vibration; oil temperature is too high; oil pollution and so on. There are various reasons for the failure of marine hydraulic equipment. Failure to meet the specification requirements during design or installation, normal wear and tear of the equipment for long-term use, and improper operation of human factors may cause hydraulic equipment or hydraulic system failures.

2. Failure characteristics

1) Diversity and complexity of faults. Several faults are often intertwined. Some are caused by the failure of one hydraulic component, some are affected by the comprehensive factors of multiple hydraulic spare parts in the system, and some are caused by the simultaneous failure of hydraulic and electrical components.

2) Even if the ship hydraulic equipment has the same fault, the cause is different. In particular, the current ship hydraulic equipment is a common combination of mechanical, hydraulic, electrical and even microcomputers, and the causes of failures are more diverse. Even if it is the same reason, it may cause different failures.

3 Failure analysis and elimination of hydraulic equipment

Since hydraulic equipment failure has the above characteristics compared with other equipment failures, the method of dealing with hydraulic equipment failure and the method of dealing with other equipment failures have their own characteristics in addition to certain commonalities. To deal with hydraulic equipment failure, it is necessary to analyze the factors that cause the failure one by one. However, various components, auxiliary mechanisms and oil are mostly enclosed in the housing and pipeline, unlike mechanical transmission, which is directly observed from the outside, and the measurement is also It is not as convenient as the electrical system, and the hydraulic components are all working under sufficient lubrication conditions, and the system is equipped with overload protection devices, so there is little damage to parts. Therefore, when a hydraulic equipment fails, it often takes more time to find the cause, and it is more troublesome to troubleshoot. -In general, any failure will be accompanied by various abnormal phenomena before it evolves into a major failure. If the system has abnormal sound; the speed of the actuator decreases, the action is weak or does not work; the oil level drops; the oil deteriorates; the leakage increases; the oil temperature is too high; the burnt smell appears. The above-mentioned fault phenomena can be found through basic methods such as seeing, hearing, touching, sniffing and so on. Only by fully understanding the fault situation and carefully and scientifically analyzing the internal laws of the fault can we find out the real cause of the fault and deal with it reasonably. Next, the author will talk about the analysis and treatment methods of a few cases of failure based on the practice of working on the ship.

3.1Action failure

The speed of the traveling components is too slow or the operation instructions are not executed. This is the failure of the hydraulic device of the cabin cover that has more failures in the daily maintenance and management. The initial stage of the fault is the gradual decrease in speed during work until it fails to work normally. The result of the inspection found that the hydraulic gear pump I used in the system had been working for too long, and the oil temperature continued to rise with the extension of time during work; there were black debris on the inlet filter of the pump. After removing the black debris, the test found that although the speed increased slightly, it still could not meet the requirements of normal use, and the system oil temperature continued to rise. When it rises to 60~70°C, the opening and closing of the hatch will no longer act. The dismantling of the gear pump found that the gear pump was very severely worn, and the axial and radial clearances were much beyond the permitted range. After replacing the new gear pump, the equipment and system returned to normal. It can be seen that the failure is caused by the low volumetric efficiency of the pump after severe wear. At the beginning of work, the oil temperature is low, and the oil in the system has a high degree of stiffness, and it can work according to the design requirements. When the working time is long, the oil temperature is high, the stiffness decreases, and the internal leakage of the pump increases, causing the pump to work abnormally.

3.2Noise and vibration

The causes of noise and vibration failures are very complex. Not only the mechanical equipment and electrical appliances of the system can cause noise and vibration, but also within the hydraulic system, almost every link can cause noise and vibration. Air mixing in the system; mechanical vibration; failures of components such as hydraulic pumps, hydraulic motor and control valves; pressure and flow pulsations in the system, and the resulting resonances, are all causes of noise and vibration. It is very difficult to analyze and deal with this kind of fault. It is necessary to make a preliminary judgment based on the characteristics of the fault, which type of cause is caused, and then through oiling, sniffing, inspection, and even disintegration inspection, find the cause of the fault and eliminate it.

ELEPHANT FLUID POWER mainly focuses on Hydraulic parts, such as hydraulic pump, Hydraulic motor, Hydraulic valve. Service areas are heavy equipment and construction machinery, including the Mining machines, Earth Moving, Construction Vehicles…