Vertical Roller Mill Hydraulic System

Vertical Roller Mill Hydraulic System

Nine types of faults in vertical roller mill hydraulic system analysis and solutions

There are various faults in the operation of the vertical roller mill hydraulic system. For example, if the roller does not lift up or it cannot be pressurized, there is also a failure phenomenon such as the rupture of the nitrogen gas bladder of the gas storage tank and the unstable vibration of the hydraulic system. This article shares nine kinds of fault phenomena and corresponding solutions for vertical roller mill hydraulic system.

Accumulator gas storage tanks were damaged by nitrogen airbags, and there was a "squeaky" sound, and the pipes produced shock vibrations. Using a special pressure gauge to check if the pressure of the nitrogen bladder in the storage tank is reduced or severely zero. If the pressure is reduced or zero, the nitrogen balloon will be leaked and damaged.

Main reasons: The quality of the nitrogen air bag is not good, the inlet and outlet valves of the gas tank are damaged, and the impurities in the hydraulic oil cause the pressure fluctuation of the nitrogen air bag to cause vibration shocks and click noise.

Solution: Replace the nitrogen gas bags made by professional manufacturers or replace the damaged gas storage tank inlet and outlet valves and improve the bacteria valve structure to improve the stem strength, clean up the impurities in the hydraulic pipeline, and use the oil filter with filtration accuracy of no more than 5��m to filter , Add hydraulic oil to reach NAS7 level.

Hydraulic flange leak. The main reasons are: aging of seals, improper installation or extrusion of burrs, or unevenness of flanges, looseness of flange dislocation bolts, stress of flanged pipes, and misalignment of flanges. Solution: Regularly (12 months inspection) replace the aging seals; when installing the seals, correct and completely put them into the groove to prevent the force from damaging the seal and failure; adjust the two flanges of the pipe concentric and In parallel, evenly tighten the connecting bolts and secure the pipes to prevent oscillating oil leakage.

When the oil pump and filter are working normally, the roller lift roller is normal, the roller does not drop when the roller is lowered or the lifting roller does not move. The main reason: hydraulic oil does not enter the rod cavity of the oil cylinder, resulting in no pressure, and it is impossible to lower the grinding roller. The main reason why the lifting roller does not move is that the hydraulic oil does not enter the rodless cavity and the rod cavity of the oil cylinder, resulting in the inability to load and cannot lift the roller.

Solution: After analyzing and checking the three-position four-way electromagnetic valve, the spool can only work on one side, the other side can not work, or both sides can not normally switch to work due to wear or oil stuck. The worn three-position four-way solenoid valve replaced the new one; the dirty oil led to seizure, the three-position four-way solenoid valve was disassembled and cleaned, and the hydraulic oil was filtered. The cylinder was working normally and the lifting roller was normal.

Two of the four rollers can lift the roller to a defined position. The other two roller rollers have a slower speed and do not lift the roller in place for a set time (120 seconds). The main reason: According to the fact that there are already two rollers that can be lifted up, there is no problem in diagnosing the hydraulic system and there are no other mechanical problems to check. The main reason is that the internal oil of the other two grinding roller cylinders can also have a compression space, and the lift roller slowly has an excess gas inside the cylinder. Solution: After the rod cylinder chamber is safely depressurized, use a wrench to loosen the exhaust plug of the fuel tank. Discharge the gas in the cylinder in a timely manner, and then turn on the pump again. The four rollers simultaneously lift the roller in place.

Roller does not rise. The central control operation starts the lift roller command until the end of the program, and the on-site roller does not rise. According to operating experience, combined with the principle of hydraulic control system, comprehensive diagnosis is caused by oil not entering the cylinder without rod cavity or leakage in pipelines and hydraulic components. The main reason is that the system filter is clogged; the oil pump is not damaged and no oil enters the rodless cavity cylinder; no rod cavity pipeline leaks; the stop valve on the rodless cavity pipeline is not closed; the solenoid valve is still energized or the spool is not in place after the power is off; Control check valve stuck.

Solution: Clean the clogged filter; Replace the damaged oil pump; Handle flangeless pipe flange seals; Close the shut-off valve connected to the non-rod cavity piping, tightly leak-free; handle the solenoid valve off or clean the solenoid valve core Clean the hydraulic pilot check valve controlled by the solenoid valve and filter the hydraulic oil. After the above implementation method, the hydraulic system works normally and the roller lift roller is normal.

Roller load pressure does not rise and it cannot be pressurized. The roll cannot fall. The main reason is that: the oil stop valve is not closed; there is a leakage in the rod chamber; the solenoid valve is still live or after the power failure; the valve core is not in place; the solenoid-controlled check valve is stuck; the overflow valve jams. leakage. Solution: Close the corresponding oil stop valve; handle the leak in the rod chamber; solenoid valve power off or clean the valve core; clean the solenoid valve control hydraulic check valve; After the implementation method above, the hydraulic system works normally and the roller pressurization roll-down roller works normally.

The hydraulic oil pump and cylinder hydraulic system work normally. After a certain roller is pressurized, the piston of the cylinder increases and decreases at a smaller speed, and the piston rod is less flexible or does not move. The main reason: Check and found that the piston rod connecting the rod piston rod bearing broken crack damage; hanger rod from the screw position to produce old defects crack. Solution: Remove the broken rod bearing and replace it with a new one. The grinding mill will work normally. Replace the new lug lever assembly.

During the normal production and operation of the vertical roller mill, the hydraulic system of the hydraulic cylinder works normally, and when the flashing is loaded, the entire cylinder moves up and down.

The main reason is that the bearing of the cylinder base hanging ear is broken and broken, and the fixing of the cylinder is not reliable. Solution: Disassemble the broken joint bearing and replace the new joint bearing GEG200ES/2RS. After loading, the oil tank does not move up and down, and it is firmly fixed and works normally.

Hydraulic piston pump produces noise. Main reason: oil is mixed with air (formation of air bubbles); loosening of the fastening bolts of the axial piston pump or motor generates external force vibration; the oil level in the oil tank is too low; the oil temperature is too low and the viscosity resistance is large. Solution: Check the system pipeline leakage points and exhaust treatment; tighten the loose anchor bolts; add oil level to the scale marking position; check the temperature control system, heating system, cooling system to achieve a good normal work to ensure the oil temperature to achieve Automatic control, fuel tank temperature control: 25 C heater start, 25 C oil pump auto start, 38 C heater stop, running oil supply port temperature control: 25 C sound and light alarm (manually turn off cooling water), 43 C sound and light alarm (manually open the cooling water).

Some failures of the vertical roller mill hydraulic system are mostly caused by hydraulic pollution due to secondary pollution caused by maintenance, improper maintenance, etc., resulting in hydraulic valve jamming. Routine maintenance, regular maintenance, and timely detection of hidden troubles can effectively improve production efficiency. Messages are welcome to communicate your problems.

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