Analysis of easy-to-see problems in hydraulics

Because of its simple structure, flexible layout, and good self-lubrication of components, the hydraulic system is easy to be combined with other transmission methods. Therefore, it has been widely used in most equipment of various enterprises at present. All key equipment such as electrolysis multi-function cranes, casting machines and tilting mixing furnaces in our factory use hydraulic transmission systems. The hydraulic system is generally a closed pipeline circulation system, and it is one of the main shortcomings of hydraulic transmission that the fault of the hydraulic system is hidden and difficult to find. Once the hydraulic system of the equipment fails, the cause of the failure should be determined as soon as possible and eliminated in time to reduce the economic loss caused by the shutdown of the equipment. Engineering and technical personnel need to rely on their own professional technical skills, basic knowledge of hydraulic transmission, hydraulic components principle structure and basic circuit knowledge to analyze the fault.



Abnormal pressure In general, many pressure measuring points are reserved in the design of the system pipeline. Use the pressure gauge to measure the reading, and compare and analyze with the normal value to determine the hydraulic components that cause the abnormal pressure. If the speed is abnormal, adjust the throttle valve, speed control valve and variable pump variable mechanism one by one, corresponding to the speed range value of the test actuator, which can be determined by comparing and analyzing with the design value. If the action is abnormal, switch each reversing valve, observe whether the action state of the relevant actuator is normal, and then find out the abnormal reversing valve, and then check the action sequence and stroke control to find out the abnormality. Others appear abnormal vibration, noise, oil leakage, heat, etc., do not rush to shut down, you should touch and see three to observe, determine the abnormal part and analyze and deal with it.






Comprehensive application of knowledge of hydraulic fluid mechanics can theoretically analyze any failure of hydraulic circuits and hydraulic components. The following example will illustrate the general search process for hydraulic faults. Fault name: hydraulic pump cavitation; fault phenomenon: vibration, noise, cavitation; main reason: the pump suction port pressure is lower than the gas separation pressure, or air is sucked in. Reasoning analysis: Use the energy equation and the flow continuity equation to analyze the oil suction process of the hydraulic pump, and determine the reason for the failure of the pump: the liquid surface pressure of the oil tank is too low --- the ventilation hole of the oil tank is blocked, and the liquid flow rate of the oil suction port of the pump is too high ;



The pressure loss of the oil filter is too large - the filter element is blocked, etc.; the resistance coefficient along the process is too large - the oil temperature is low, the viscosity is high, the total length of the oil suction pipe is too long; the inner diameter of the oil suction pipe is too small; the local resistance coefficient is too large - - The pipeline is bent, flattened, blocked, etc.; the oil suction height of the pump is too high, the pipeline is not tightly sealed, and the oil suction pipe is immersed in the liquid level of the oil tank too shallow.