Hydraulic system的故障率75%以上是由于Hydraulic oil的污染引起的，在使用液压油时要把它看做像人的血液一样保持足够的清洁度才能确保液压系统的故障率降到低限度。在液压系统中，极易造成油液污染的地方是油箱。不少油箱，在结构设计和制造上存在缺陷。常见的是封闭性油箱设计的不合理，例如在连接处、接管处不加密封，导致污染参入油箱。污染的油液进入液压系统中，加速液压元件的磨损、锈浊、堵塞，后导致故障的行程。近几年来许多制造商在油箱结构设计上做了不少有益的探索和实践，以减少或杜绝污染物进入油箱
For example, using a fully enclosed fuel tank structure, except for leaving only one vent hole connected to the atmosphere, all fuel tanks adopt a closed structure, and all connections and connections are equipped with strict sealing devices. The refueling port is equipped with a filtering device to form a vent hole, which ensures that the liquid level in the fuel tank is the same as the atmosphere and ensures the normal operation of the system, while also preventing external pollutants from entering the fuel tank. Due to the fully sealed oil tank, a filter was removed from the suction port of the pump, and all circuits returned to the mailbox through the filter on the main return oil pipeline, ensuring the cleanliness of the entire hydraulic system oil. This structure not only avoids external pollution from contaminating the oil in the tank, but also removes the filtering device from the suction port, greatly reducing the suction resistance and avoiding the occurrence of cavitation