The Failure Measure of the Hydraulic Tensioning System of Vertical Mill

Date: 2019-07-02 Views:

The fault of the hydraulic tensioning system of the vertical mill is mainly the failure of the accumulator nitrogen air bag, the frequent starting of the high-pressure oil pump of the hydraulic station, the hydraulic cylinder block strain or the oil leakage.

1. Damage of accumulator nitrogen airbag

When the pressure of the grinding roller is not balanced, the buffering force of each pull rod is different; and when the pressure is too large, the buffering capacity of the nitrogen is reduced, and the vibration of the grinding machine is caused.
The failure of the nitrogen bag can be found in time

A. Touching the temperature of the accumulator shell by hand, if it is close to the oil temperature, indicates that the accumulator is working normally; if it is obviously high or low, the accumulator should be suspected of damage and replace the airbag or one-way valve.

B. When the vertical mill is shut down, the pressure gauge is installed on the valve nozzle of the energy storage device after the hydraulic station is unloaded. If the pressure is close to the normal pressure of the nitrogen airbag, the accumulator is in good condition, otherwise the accumulator is damaged.

C. The field observation of whether the roller lifting or pressure time is obviously prolonged can indicate whether the accumulator nitrogen airbag is damaged or not.

D. Tensile rod and tensile rod bolt break frequently.

2 solution

A. The fundamental measure is to stabilize the operation condition of the mill and to avoid the sharp vibration of the mill.

B. the preloading pressure of each nitrogen airbag should be given strictly according to the set value, and check regularly, replenish nitrogen in time, and master the correct nitrogen filling method. Prevent oil leakage, leakage caused by abnormal pressure.

c. When it is found that the nitrogen airbag is damaged, the accumulator can not act as cushioning and damping shock. It cannot absorb the impact of material layer thickness change on the hydraulic system, resulting in continuous shock vibration, and also accelerates the damage of hydraulic cylinder seal and high-pressure rubber hose. At this time, replace the capsule as soon as possible.

2. The high-pressure oil pump of the hydraulic station is started frequently

When the pressure of the hydraulic system cannot be maintained during the vertical grinding operation, the high-pressure oil pump is started frequently, and the grinding efficiency of the grinder is reduced when the temperature of the hydraulic oil is increased. The cause is to be found at this time: either the rod seal of the hydraulic cylinder, the cylinder endoleak, or the internal leakage or damage of the return valve (or relief valve). In order to check whether the hydraulic cylinder has an internal leakage, the oil pump of the tensioning hydraulic station can be de-energized after the grinding is stopped, and the oil pressure of the hydraulic station is observed to be gradually reduced, and the internal leakage of the hydraulic cylinder is indicated, and the seal shall be replaced in time.

In order to prevent this kind of phenomenon, the pressure range of hydraulic station should be set reasonably. If the range is too narrow, it will not only weaken the cushioning capacity of nitrogen airbag, but also lead to frequent start and stop of high pressure oil pump in a short period of time, which will burn down the high voltage motor in serious cases. At the same time, it is necessary to regularly check and clean the hydraulic valve (and pressure relief valve) to prevent debris from blocking the valve.

3, hydraulic cylinder block strain or oil leakage

When there are impurities in hydraulic oil, fine particles are sandwiched between hydraulic cylinder and piston rod; or accumulator one-way valve handle breaks, bolts and washers enter hydraulic cylinder; all of them will pull cylinder block, piston ring, damage seal, resulting in external oil leakage. When the sealing ring of hydraulic cylinder is aging, or when the oil pressure of hydraulic cylinder continues to be high because of the high grinding pressure, oil leakage will occur when the sealing ring is damaged by high pressure for a long time.

For this reason, the hydraulic oil must be kept high cleanliness. In cylinder block inspection, pipeline cleaning, replacement of nitrogen airbag and hydraulic oil, the surrounding environment must be highly clean; the quality of hydraulic oil should be tested and checked every six months, and the oil should be replaced in time when the oil is emulsified and spoiled; reasonable setting grinding pressure, the actual operating pressure should generally be 70% of the maximum pressure limit; make a soft connection sheath outside the connecting part between the pull rod and the hydraulic cylinder to prevent the fine particle material from falling into.

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