A hydraulic power system is made up of a pump, motor, actuators, hydraulic fluid, and valves that can be used in different applications to reduce mechanical complexity and transfer power. Proper maintenance of hydraulic systems is imperative in ensuring high machine reliability. Conversely, improper maintenance can result in excessive costs in repairs, depending on the application.
The hydraulic pump is the core of the hydraulic system and the most expensive when it comes to making replacements. Some of the symptoms of a faulty hydraulic system include extremely high temperatures, noise, and reduced operation speed, which can be erratic. These are mainly caused by thermal, hydro, and air contamination that cause poor operation of the hydraulic system.
Abnormal noises: This is caused by two factors; aeration and cavitation. Aeration involves air contaminating the hydraulic fluid. As a result, there is a knocking noise or an alarming banging that is heard during compression and decompression, as the fluid circulates through the system. Other signs of trouble include unpredictable actuator movement and foaming of the hydraulic fluid.
Cavitation, on the other hand, is caused by high demand of the fluid not being met by the supply of the same. This causes a drop in vapor pressure. As a result, the fluid creates vapor cavities that implode when compressed, causing an abnormal noise. Effects of aeration and cavitation can be detrimental as they cause loss of lubrication, burning of seals, overheating, metal erosion in case of cavitation and machine breakdown.
Litigation: Cavitation mostly occurs at the pump’s inlet and as such, seals should be tightened and the intake line in the middle of the pump and reservoir should not be restricted. It’s also imperative to replace suspect or old intake lines and carry out regular checkups and maintenance. Aeration can be dealt with by frequent unclogging of inlet strainers, and if gate type valves inlets are used, they should be fully opened.
High fluid temperatures: High fluid temperatures can accelerate degradation of the fluid and damage seals. This occurs when the optimum value of the system’s components is much higher than its viscosity. This can be caused by anything that affects the system’s ability to reduce heat or increases heat load. The systems heat is lost through the reservoir and therefore, the fluid should be constantly monitored in order to ensure that it is at the correct level.
The heat of the fluid is dependent on the flow rate of both the fluid and the water circulating through the exchanger. Compression process also cause high thermal conditions when aeration and cavitation is present in the system. The side effects of this are damaged seals, inefficient lubrication that causes damage to the hydraulic system and could cause a total shut down of the system.
Litigation: Temperature alarm systems should be installed in the hydraulic machine to notify the user of abnormal temperatures. In this case, when the optimum temperatures are exceeded, then the alarm goes off and you can be able to check the cause. Always ensure that the core is not blocked by regularly inspecting the heat exchanger. Monitor the performance of all cooling circuit components and if necessary, replace worn out or old components. In addition, it is important to check that there is no buildup of dirt or debris in order to ensure that there are no obstruction to airflow.
Slow operation: Reduced performance speed is a problem that arises when a hydraulic machine is faulty. It is usually evident when the system takes longer than usual to process, in addition to reduced actuator speed. Slow operation can be highly associated with leakages, both internal and external.
External leakages can be something like a burst hose, which is easy to detect and correct. Internal leakages occur inside the hydraulic system in valves and are tied to high fluid temperatures. Increase in heat load lowers pressure in the fluid flow, vice versa, and the cycle continues to affect the system, and can cause severe damage to it.
Litigation: periodic scheduled monitoring should be conducted often and a fluid flow tester used to ensure that the flow is seamless. Temperatures should also be kept within check. Proactive monitoring of noise is also a way of dealing with slow operation as it helps detect aeration and cavitation.
Workers operating hydraulic systems can threaten the safety of your facility. Educating your employees on safe operations of these systems can help reduce workplace accidents and injuries. Interested in enrolling your workers for safety training when operating hydraulic systems? Consider the Hydraulics Training & System Troubleshooting at NTT Training. Contact us today to learn more about the program.
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