The cause and solution of partial failure of hydraulic system of vertical mill

Date: 2019-07-15 Views:

During the operation of the hydraulic system of the vertical mill, there will be all kinds of faults, such as the roller can not rise up or can not load the pressure, and the nitrogen airbag of the gas storage tank may be broken and damaged, and the vibration of the hydraulic system may be unstable and so on. This paper introduces some fault phenomena and corresponding solutions of vertical mill hydraulic system.

1. The nitrogen airbag of accumulator gas storage tank is damaged, the sound of banging appears, and the pipe produces impact vibration.


The special pressure gauge is used to detect whether the pressure of the nitrogen air bag of the gas storage tank is reduced or seriously is zero, and if the pressure is reduced or zero, the leakage of the nitrogen air bag is indicated.

The main reasons are as follows: the quality of nitrogen airbag is not good, the inlet and outlet valve of gas storage tank is damaged, and the impurities in hydraulic oil lead to the vibration impact and "banging" noise caused by the pressure fluctuation of nitrogen airbag breakage.

Solution: replace the high-quality nitrogen air bag made by the professional manufacturer or replace the damaged air storage tank inlet and outlet valve and improve the bacterial type valve structure to improve the strength of the valve stem, clean the impurity of the hydraulic pipeline and filter with the oil filter with the filtering precision of not more than 5 & mu; m, and add hydraulic oil to the NAS7 level.

 

2. Under the normal working condition of oil pump and filter, the roller lifting is normal, and the grinding roll does not drop or the lifting roll does not move when the roller falls.


Main reason: hydraulic oil does not enter the cylinder with rod cavity, resulting in unable to pressure, can not reduce grinding roller. The main reason is that the hydraulic oil does not enter the cylinder without rod cavity and rod cavity, resulting in unable to load, can not lift the roll.

Solution:After analysis, the three-position four-way solenoid valve can only work on one side, the other side cannot work, or both sides cannot work normally due to wear or oil dirt. Replace the worn three-position four-way solenoid valve;Oil dirt causes jamming, disassembly, cleaning three-position four-way solenoid valve, and filtering hydraulic oil, normal operation of oil cylinder, and normal lifting grinding roller.

 

3. Two of the four grinding rollers can be lifted to a defined position, and the other two grinding roller lifting rollers are slow in speed, and the roller can not be lifted in place during the set time (120s).


Main reason: According to the condition that the two grinding rollers can be raised, the diagnosis hydraulic system is free of problems, and the inspection is free of other mechanical problems. The main reason is that the oil in the other two grinding roller cylinders can also have a compression space, and the inside of the lifting roller slowly cylinder is caused by excessive gas.

Solution: After the oil cylinder has no rod cavity to be safely released, the oil cylinder exhaust plug is released by a spanner, the gas in the oil cylinder is released in time, the oil pump is opened again, and the four grinding rolls are in normal position at the same time.

4. The grinding roller is not raised.


The central control operation starts the roller lift command until the end of the program, the field roller does not rise. According to the operation experience and the principle of hydraulic control system, the comprehensive diagnosis is caused by the oil not entering the cylinder without rod cavity or leakage in the pipeline and hydraulic components.

Main reasons:

(1) blockage of system filter;

(2) the oil pump is damaged and no oil enters the rod-less cavity cylinder;

(3) leakage of pipe without rod cavity;

the stop valve on the non-rod-free cavity pipeline is not closed;

The valve core is not in place after the solenoid valve is still energized or de-energized;

The hydraulic control one-way valve is stuck.

Solution:

(1) cleaning blockage filter;

Replace the damaged oil pump;

(3) to deal with the flange seal of the pipe without rod cavity;

④ Close the stop valve connected to the pipe without rod cavity, and make sure there is no leakage;

(5) treatment of solenoid valve power outage or cleaning solenoid valve core;

Clean the hydraulic one-way valve controlled by the solenoid valve and filter the hydraulic oil.

After the above measures are adopted, the hydraulic system works normally, and the grinding roller lifting roller is normal.

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