Hydraulic systems can be effectively divided into closed systems and open systems according to the oil circulation mode during operation.
A closed system mainly refers to the connection between the oil inlet pipe of the hydraulic pump and the oil return port of the actuating element. In this way, the hydraulic oil output from the oil outlet of the pump flows out through the outlet of the actuator and directly returns to the inlet of the pump, making the working fluid circulate in a closed manner in the pipelines of the system. In the closed system of the hydraulic system, the oil inlet pipe of the hydraulic pump is directly connected to the oil return pipe of the actuating element, and the working fluid circulates in a closed way in the pipelines of the system. It has a compact structure and little chance of contact with air, so air is not easy to infiltrate into the system, resulting in relatively stable transmission. Moreover, bidirectional movement can be realized without a reversing valve. In a closed hydraulic system, the entire loop is under pressure, and the elastic modulus of the hydraulic oil is high and relatively stable, which is conducive to improving the response speed and control accuracy of the system.
An open system mainly means that the hydraulic pump draws oil from the oil tank. After passing through various control valves, the oil drives the hydraulic actuating elements, and the return oil flows back to the oil tank through the reversing valve. The overall structure of the hydraulic system is very simple. During use, the oil tank can play the role of heat dissipation and impurity precipitation. However, because the oil is often in contact with air, air easily infiltrates into the system, leading to consequences such as unsteady movement of the mechanism. The open system has a large oil tank, and the self-priming performance of the oil pump is good. n be realized.
