Created on:2021-07-20 09:58

Failure of hydraulic pump and relief valve of coke oven hydraulic exchange

Failure of hydraulic pump and relief valve of coke oven hydraulic exchange

Metallurgical equipment is one of the key application fields of hydraulic technology. Hydraulic system is widely used in ironmaking, steelmaking and continuous casting, steel rolling, coiling and heating furnace.

Hydraulic fault diagnosis and maintenance of ironmaking and coking equipment

(1) Pressure fault of coke oven hydraulic system

The main equipment of coke oven in a factory is four cars and one machine (coke pushing car, coke blocking car, coal feeding car, coke quenching car, hydraulic switch).

All hydraulic pumps are. The hydraulic pump of the gas hydraulic exchange is inside the oil tank. Compared with the hydraulic pump outside the oil tank, it is not easy to find the fault in time.

① Fault I: the pressure of the switch doesn't go up, and the sound of the pump starting is particularly loud. It was found that the needle roller bearing of the hydraulic pump had been broken, resulting in high noise of the vane pump and the speed could not meet the requirements. This is due to the improper installation method of the hydraulic pump coupling and the excessive impact on the bearing of the hydraulic pump. Therefore, when installing the coupling, it is required to use a special press fitting tool or hot fitting method. After pressing, gently tap the coupling through the base plate to eliminate the jamming caused by inclination. It is forbidden to strike the end of coupling directly with hammer. Finally, check the radial and end run out at the flange.

② Fault II: after the installation of the hydraulic pump, the sound is louder than normal. After using for a period of time, the sound is louder and louder, and the final pressure can not meet the use requirements. The hydraulic pump was disassembled and inspected. It was found that the inlet pipe of the hydraulic pump was very loose. After the inlet pipe was fastened and installed, the fault disappeared. This is the inlet pipe seal is not tight, resulting in air into the fault. Treatment: when installing the hydraulic pump, carefully check the inlet and outlet oil pipe seal to avoid leakage, so as not to enter the air.

③ When replacing the motor of hydraulic pump with other faults, the wrong wire connection caused the reverse rotation of hydraulic pump; Abnormal changes of system pressure are caused by too low liquid level of oil tank or too low temperature in winter. For the reverse rotation of hydraulic pump, the measures taken are to adhere to the system of test run inspection after maintenance and deal with it in time. For the low oil level of the oil tank, the measure taken is to restore the level gauge of the oil tank. If there is no liquid level gauge, the oil level should be observed frequently through the oil filling port of the oil tank. For the problem of low temperature in winter, the solution is to turn on the heater if there is a heater, and turn on the hydraulic pump for half an hour before starting production if there is no heater.

(2) Overflow valve failure

The most common cause of no pressure in hydraulic system is that the electromagnetic relief valve does not act. The way to check this kind of fault is: press down the manual button of the overflow valve electromagnet, the system pressure will be normal immediately, then we can judge whether the electromagnet is burnt out or not energized, and then carry out the corresponding inspection and treatment; If the manual button can not be pressed, check whether the electromagnetic valve core is stuck; When the manual button of the overflow valve electromagnet is pressed down, the system pressure is still not available. At this time, it is necessary to check whether it is its own fault.

① Fault I there is no pressure in the hydraulic system of No.1 coke blocking car. After inspection, it was found that there was a broken sealing ring on the damping hole of the main valve core of the relief valve, which caused the hydraulic pressure could not be transmitted to the upper chamber of the main valve and the front chamber of the poppet valve, and the pilot valve lost its regulating effect on the pressure of the main valve. Because there is no pressure in the upper chamber of the main valve and the spring force is very small, the main valve becomes a direct acting relief valve with very low pressure. When the pressure in the oil inlet chamber is very low, the main valve core will open to overflow and the system will not be able to establish pressure. After the broken pieces of the sealing ring are removed and installed, the fault is eliminated.

② Fault II: the system pressure of the hydraulic station of No.2 coke pusher is relatively low, and the pressure of the pressure regulating hand wheel is still lower than the working pressure. The relief valve was disassembled. After inspection, it was found that the spring of the pilot valve was broken, so the spring pressure was very small, the pilot valve was in the open state, there was liquid flow in the damping hole of the pilot valve, and the pressure difference between the upper and lower cavities of the main valve piston caused the main valve to open and overflow. Because the spring of the pilot valve is broken, adjusting the pressure regulating hand wheel can not increase the stiffness of the spring, so that the pilot valve is closed, so the above fault occurs. The solution is to replace the pressure regulating spring.

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