tThe fault of coke oven hydraulic switch system
The fault of coke oven hydraulic switch system
① Fault I: the system pressure of No.1 coke pusher suddenly dropped to a very low level when it was moving forward. At this time, when the door trolley is at the rear limit position, the system pressure is also very low. The system pressure is normal when the action of the door taking trolley is stopped and other actions are carried out. According to this phenomenon, it should be the short circuit between the pressure oil circuit and the return oil circuit after the reversing valve of the trolley branch system. Open the oil return pipe joint of the forward cylinder of the door taking trolley to move forward. The phenomenon is that the hydraulic oil leaks from the oil return port of the cylinder, and there is no oil in the oil return pipeline. Therefore, it is considered that the front cylinder of the gantry crane is faulty. When the hydraulic cylinder was opened, it was found that the threaded connection between the piston rod and the piston was tripped, which caused the passage inside the cylinder. The problem is solved by connecting the piston rod with the piston again.
② Fault II: when the No.1 coke blocking car hooks, the system pressure suddenly decreases; However, when the hook is forced to drop, the system pressure is normal. As shown in figure a, although the hook dropping and hooking actions control the door cylinder to do opposite actions, it does not use a three position four-way directional valve, but uses two two position four-way directional valves to control; In addition, there are six two position four-way valves to control the same hydraulic cylinder. Drop the hook, drop the door, and then lift down to control the downward movement of the piston rod of the lifting door hydraulic cylinder; Hook, lift door, and then lift to control the upward movement of piston rod. They are opposite each other and jointly control the lifting cylinder. There are many reasons for this phenomenon, such as one-way valve failure, electrical control failure, pipeline leakage and so on. The situation is normal when the last cycle action is combined with the post; And at this time, the piston rod of the door cylinder has fallen to the bottom, which is almost the same as the position of the hook limit, so it is difficult to detect the abnormality.
When there is no action, the oil pipe in the upper chamber of the hydraulic cylinder also has pressure, so it is preliminarily determined that when the hook is dropped in the last action of the previous working cycle, the spool of the hook dropping directional valve is stuck or the return spring is broken, so that the hook dropping directional valve cannot be reset.
When other directional valves control the lifting cylinder to do the opposite action, the hydraulic pipeline is short circuited, and the hydraulic oil does not return to the oil tank directly through the actuator, resulting in a sudden drop in pressure. The hydraulic system returned to normal after the change-over valve was replaced.