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The hydraulic pressure fluctuation and the surge of the roll-type vertical mill hydraulic system and the solution

Date:2019-07-15 12:51 Source:未知Views:

The present roll mill requires a hydraulic system to provide a grinding load pressure. The grinding roller is pressed on the material layer of the grinding disc, and the grinding disc is operated at a low speed under the driving of the speed reducer, so that the grinding effect of the material is achieved. In operation, that pressure fluctuation of the hydraulic system and the problem of the surge of the hydraulic system are often encountered. The following simple analysis is made from the angle of the hydraulic system:

I. Hydraulic fluctuation

 

The pressure fluctuation of the hydraulic system is generally divided into active and driven fluctuation.

 

1. Active fluctuation.

This is generally due to the decrease in the hydraulic pressure holding capacity of the hydraulic system (including the pump set, solenoid valve, cylinder system). For example, the lower limit of the constant fluctuation pressure on the regular habitual setting is 0.5 MPa of the set value. The oil pump below the lower limit hydraulic system will start automatically until the upper limit of 0.5 MPa is reached, and the pump will be stopped; when the pressure drop is lower than the set value of 0.5 MPa, the oil pump will start the pressure and pressure, resulting in the periodic pressure fluctuation of the hydraulic system. If the fluctuation is too frequent, the pressure of the grinding roller is not stable, and the vibration frequency of the grinding roller can be increased. in severe case, that oil will be cause The cylinder oil exchange is not enough, the shock absorption capacity of the accumulator group is not enough, and the vibration amplitude of the mill exceeds the standard and stops the grinding. And then affect the continuity and stability of production.

Solutions:


Check the viscosity and cleanliness of hydraulic oil regularly and control it within the national standard. After the hydraulic oil exceeds the standard, the high vacuum oil filter should be used to filter and maintain the hydraulic oil in time, and the rules and regulations of regular maintenance of the hydraulic oil should be done well.

Check the leakage and internal leakage of the cylinder.

Check the grinding conditions of the valve group and the pump. Prepare the spare parts reserve in advance, and replace the spare parts in time.

Regularly formulate cleaning tank bottom and magnetized rod iron powder cleaning and other maintenance measures.

2. Driven fluctuation.

In general, the grinding property of the material is poor (for example, the iron content of the water slag is increased), the dry humidity is poor, the material layer is not stable, the size of the raw material is increased, and the self-contained upper and lower cross-movement of the grinding roller is caused. And is characterized in that the expansion frequency of the piston rod of the oil cylinder is increased. The amount of oil exchange increases and the accumulator set is not sufficient to provide the corresponding hydraulic oil, then the loading station exhibits a hydraulic pointer swinging back and forth.

The pipe shook violently. When the exchange is insufficient, the bacterial valve core will be sucked to death by the negative pressure of the pipe after the valve core is closed, and the valve core will not be opened until the oil pump starts to replenish the pressure. The cylinder continues to vibrate, and the shielded accumulator no longer absorbs, so the vibration may continue to increase. It even causes the vibration amplitude of the mill to exceed the standard to stop grinding. In addition, the vibration amplitude of the powder separator is too large, the horizontal and vertical amplitude of the mill is larger, and the pressure fluctuation caused by the roller vibration is very small. This factor is relatively rare and can be ignored.

Solution:

the amount of iron contained in the control material is controlled, the thickness of the material layer is increased by proper water spraying, and the size of the abrasive is controlled. In addition, this also indicates that the shock-absorbing relief of the accumulator set is not sufficient. The damping capacity of the hydraulic system can be improved by basically increasing the number of the bacterial type valve and the leather bag in the existing pipeline. The stability of the hydraulic system is improved, the selection and the containing capacity of the mill to the material is enhanced or the tolerance is called, and the stability of the grinding machine is improved. Make sure that the production is continuous and stable. If the number and volume of the accumulator is too large, it may affect the lifting speed.

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