The main performance of flow anomaly in hydraulic system is:

(1) Because of the blockage of the filter and so on, so that the hydraulic pump oil shortage, hydraulic system oil shortage, causing the work of slow or no action, resulting in the execution of the mechanism of the movement failure or even out of control.

(2) hydraulic pumps, hydraulic cylinders, hydraulic valves or pressure pipelines, such as leakage, not only to increase the consumption of fuel, but also caused by work pressure, so that the output of the work force is insufficient, leakage is not even form the pressure of serious. (3) The frequent fluctuation of flow intensifies the vibration and noise of the system, and the filtration performance of the filter is greatly reduced, the result is that the contamination degree of oil can not be controlled in the predetermined level, which threatens the normal operation of the hydraulic system seriously.

When the flow fluctuation is large, it will cause the hydraulic impact, which is the main reason for the damage of some hydraulic equipment. (4) When the leakage of some components in the power unit is too large, the pressure of the hydraulic oil can be converted into heat energy. If the radiator capacity is limited or the heat dissipation is poor, the hydraulic oil balance temperature rise, resulting in a short period of high oil temperature, oil viscosity drop, further increase the leakage, resulting in volumetric efficiency and the overall system efficiency significantly reduced, and caused rubber seals, hoses and other early aging, loss of function.

The movement speed of the actuator in the hydraulic system should meet the specified speed range, requiring no creeping phenomenon at low speeds, no hydraulic impact at high speed, smooth speed switching, small speed changes under variable load conditions, and so on. According to the actual use of hydraulic equipment in the field of statistics, the hydraulic system in the implementation of the failure phenomenon is often: no movement, instability, movement direction is not correct, the speed of movement is not in line with the requirements, Action sequence disorder, force output instability, crawling and other forms. These kinds of fault forms are closely related to flow anomaly.

Therefore, when the hydraulic actuator is not working properly, it is often possible to find out the cause of the malfunction by flow this working parameter and eliminate it. The flow anomaly of the hydraulic system refers to the 4 kinds of situations, such as no flow into the executive body, insufficient flow of supply executing agencies, unstable oil pump output flow and excessive flow of the actuator.